WorldWideScience

Sample records for total leaf water

  1. Dew water effects on leaf water using a stable isotope approach

    Science.gov (United States)

    Kim, K.; Lee, X.

    2009-12-01

    The presence of dew is a common meteorological phenomenon in field conditions and takes into account for significant portion of hydrologic processes in terrestrial ecosystems. The isotope composition of leaf water plays an important role in the isotopic water and carbon fluxes between terrestrial plants and the atmosphere. However, the consequence of dew formation in the plant-atmosphere relations has been ignored in many studies. The objective of this study is to improve our understanding of environmental and biological controls on the leaf water in equilibrium with dew water through laboratory experiments. Five species of plants (soybean, corn, sorghum, wheat, cotton) were grown hydroponically with water of a known isotopic content in a greenhouse. On the day of the experiment, they were first moved to ambient environment in full sunlight for at least 6 hr and then into a dark container inside the lab for up to 48 hr in which water vapor isotope ratios, temperature, and humidity were controlled. This arrangement created a step change in the forcing on the plant isotopic exchange. Leaves were sampled prior to the transfer to the dark container and 6 more times every 4 - 12 hr over the experiment. Humidity inside the container was saturated to mimic dew events in field conditions. Water from the leaf samples was extracted by a vacuum line and was analyzed for both δD and δ18O. The dataset will allow us to evaluate leaf water isotopic theories by exploring the transitions of the isotopic ratio of leaf water in response to the step change. Specifically, we are interested in whether the stomatal opening is an effective pathway for gaseous exchange in total darkness and how the transitional behaviors of the isotopic ratio of leaf water differ between the C3 and C4 photosynthesis pathways.

  2. The relationship between leaf water status, gas exchange, and spectral reflectance in cotton leaves

    Science.gov (United States)

    Bowman, William D.

    1989-01-01

    Measurements of leaf spectral reflectance, the components of water potential, and leaf gas exchanges as a function of leaf water content were made to evaluate the use of NIR reflectance as an indicator of plant water status. Significant correlations were determined between spectral reflectance at 810 nm, 1665 nm, and 2210 nm and leaf relative water content, total water potential, and turgor pressure. However, the slopes of these relationships were relatively shallow and, when evaluated over the range of leaf water contents in which physiological activity occurs (e.g., photosynthesis), had lower r-squared values, and some relationships were not statistically significant. NIR reflectance varied primarily as a function of leaf water content, and not independently as a function of turgor pressure, which is a sensitive indicator of leaf water status. The limitations of this approach to measuring plant water stress are discussed.

  3. Are leaf physiological traits related to leaf water isotopic enrichment in restinga woody species?

    Directory of Open Access Journals (Sweden)

    BRUNO H.P. ROSADO

    2013-09-01

    Full Text Available During plant-transpiration, water molecules having the lighter stable isotopes of oxygen and hydrogen evaporate and diffuse at a faster rate through the stomata than molecules having the heavier isotopes, which cause isotopic enrichment of leaf water. Although previous models have assumed that leaf water is well-mixed and isotopically uniform, non-uniform stomatal closure, promoting different enrichments between cells, and different pools of water within leaves, due to morpho-physiological traits, might lead to inaccuracies in isotopic models predicting leaf water enrichment. We evaluate the role of leaf morpho-physiological traits on leaf water isotopic enrichment in woody species occurring in a coastal vegetation of Brazil known as restinga. Hydrogen and oxygen stable isotope values of soil, plant stem and leaf water and leaf traits were measured in six species from restinga vegetation during a drought and a wet period. Leaf water isotopic enrichment relative to stem water was more homogeneous among species during the drought in contrast to the wet period suggesting convergent responses to deal to temporal heterogeneity in water availability. Average leaf water isotopic enrichment relative to stem water during the drought period was highly correlated with relative apoplastic water content. We discuss this observation in the context of current models of leaf water isotopic enrichment as a function of the Péclet effect. We suggest that future studies should include relative apoplastic water content in isotopic models.

  4. Are leaf physiological traits related to leaf water isotopic enrichment in restinga woody species?

    Science.gov (United States)

    Rosado, Bruno H P; De Mattos, Eduardo A; Sternberg, Leonel Da S L

    2013-09-01

    During plant-transpiration, water molecules having the lighter stable isotopes of oxygen and hydrogen evaporate and diffuse at a faster rate through the stomata than molecules having the heavier isotopes, which cause isotopic enrichment of leaf water. Although previous models have assumed that leaf water is well-mixed and isotopically uniform, non-uniform stomatal closure, promoting different enrichments between cells, and different pools of water within leaves, due to morpho-physiological traits, might lead to inaccuracies in isotopic models predicting leaf water enrichment. We evaluate the role of leaf morpho-physiological traits on leaf water isotopic enrichment in woody species occurring in a coastal vegetation of Brazil known as restinga. Hydrogen and oxygen stable isotope values of soil, plant stem and leaf water and leaf traits were measured in six species from restinga vegetation during a drought and a wet period. Leaf water isotopic enrichment relative to stem water was more homogeneous among species during the drought in contrast to the wet period suggesting convergent responses to deal to temporal heterogeneity in water availability. Average leaf water isotopic enrichment relative to stem water during the drought period was highly correlated with relative apoplastic water content. We discuss this observation in the context of current models of leaf water isotopic enrichment as a function of the Péclet effect. We suggest that future studies should include relative apoplastic water content in isotopic models.

  5. Spectral reflectance relationships to leaf water stress

    Science.gov (United States)

    Ripple, William J.

    1986-01-01

    Spectral reflectance data were collected from detached snapbean leaves in the laboratory with a multiband radiometer. Four experiments were designed to study the spectral response resulting from changes in leaf cover, relative water content of leaves, and leaf water potential. Spectral regions included in the analysis were red (630-690 nm), NIR (760-900 nm), and mid-IR (2.08-2.35 microns). The red and mid-IR bands showed sensitivity to changes in both leaf cover and relative water content of leaves. The NIR was only highly sensitive to changes in leaf cover. Results provided evidence that mid-IR reflectance was governed primarily by leaf moisture content, although soil reflectance was an important factor when leaf cover was less than 100 percent. High correlations between leaf water potentials and reflectance were attributed to covariances with relative water content of leaves and leaf cover.

  6. Wind increases leaf water use efficiency.

    Science.gov (United States)

    Schymanski, Stanislaus J; Or, Dani

    2016-07-01

    A widespread perception is that, with increasing wind speed, transpiration from plant leaves increases. However, evidence suggests that increasing wind speed enhances carbon dioxide (CO2 ) uptake while reducing transpiration because of more efficient convective cooling (under high solar radiation loads). We provide theoretical and experimental evidence that leaf water use efficiency (WUE, carbon uptake per water transpired) commonly increases with increasing wind speed, thus improving plants' ability to conserve water during photosynthesis. Our leaf-scale analysis suggests that the observed global decrease in near-surface wind speeds could have reduced WUE at a magnitude similar to the increase in WUE attributed to global rise in atmospheric CO2 concentrations. However, there is indication that the effect of long-term trends in wind speed on leaf gas exchange may be compensated for by the concurrent reduction in mean leaf sizes. These unintuitive feedbacks between wind, leaf size and water use efficiency call for re-evaluation of the role of wind in plant water relations and potential re-interpretation of temporal and geographic trends in leaf sizes. © 2015 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

  7. Seasonal patterns of leaf gas exchange and water relations in dry rain forest trees of contrasting leaf phenology.

    Science.gov (United States)

    Choat, Brendan; Ball, Marilyn C; Luly, Jon G; Donnelly, Christine F; Holtum, Joseph A M

    2006-05-01

    Diurnal and seasonal patterns of leaf gas exchange and water relations were examined in tree species of contrasting leaf phenology growing in a seasonally dry tropical rain forest in north-eastern Australia. Two drought-deciduous species, Brachychiton australis (Schott and Endl.) A. Terracc. and Cochlospermum gillivraei Benth., and two evergreen species, Alphitonia excelsa (Fenzal) Benth. and Austromyrtus bidwillii (Benth.) Burret. were studied. The deciduous species had higher specific leaf areas and maximum photosynthetic rates per leaf dry mass in the wet season than the evergreens. During the transition from wet season to dry season, total canopy area was reduced by 70-90% in the deciduous species and stomatal conductance (g(s)) and assimilation rate (A) were markedly lower in the remaining leaves. Deciduous species maintained daytime leaf water potentials (Psi(L)) at close to or above wet season values by a combination of stomatal regulation and reduction in leaf area. Thus, the timing of leaf drop in deciduous species was not associated with large negative values of daytime Psi(L) (greater than -1.6 MPa) or predawn Psi(L) (greater than -1.0 MPa). The deciduous species appeared sensitive to small perturbations in soil and leaf water status that signalled the onset of drought. The evergreen species were less sensitive to the onset of drought and g(s) values were not significantly lower during the transitional period. In the dry season, the evergreen species maintained their canopies despite increasing water-stress; however, unlike Eucalyptus species from northern Australian savannas, A and g(s) were significantly lower than wet season values.

  8. Effects of leaf movement on leaf temperature, transpiration and radiation interception in soybean under water stress conditions

    International Nuclear Information System (INIS)

    Isoda, A.; Wang, P.

    2001-01-01

    Varietal differences in leaf movement were examined in terms of radiation interception, leaf temperature and transpiration under water stressed conditions. Five cultivars (Qindou 7232, Gaofei 16, Dongnong 87 - 138, 8285 - 8 and 8874) were grown in a concrete frame field in Xinjiang, China. Irrigation treatments (irrigation and no irrigation) were made from the flowering to the pod filling stage. A leaflet in the uppermost layer of the canopy was restrained horizontally. Leaf temperatures, transpiration rate (stem sap flow rate of the main stem per unit leaf area) and intercepted radiation of each leaflet were measured. There were greater varietal differences in leaf movement, leaf temperature and transpiration rate. Leaf temperature seemed to be adjusted by leaf movement and transpiration. The extent to which is adjusted by leaf movement and transpiration differed among the cultivars; leaf temperature was influenced mainly by leaf movement for Gaofei 16 and Dongnong 87 - 138, mainly by transpiration for Qindou 7232 and 8874, and by both for 8285 - 8. Intercepted radiation in the upper two layers of the canopy (20 cm from the uppermost) was greater in the irrigated plot, although the mean values of total leaflets of the irrigated plot were not different as compared to the non-irrigated plot. Although paraheliotropic leaf movement decreased radiation interception, it offers some possibilities for the improvement in radiation penetration within a dense canopy. Cumulated amount of transpiration during a day was compared between the restrained-leaf and the non-leaf-restrained plants in 8874. Paraheliotropic leaf movement reduced water loss by 23% in the irrigated and 71% in the non-irrigated plots

  9. Leaf water stable isotopes and water transport outside the xylem.

    Science.gov (United States)

    Barbour, M M; Farquhar, G D; Buckley, T N

    2017-06-01

    How water moves through leaves, and where the phase change from liquid to vapour occurs within leaves, remain largely mysterious. Some time ago, we suggested that the stable isotope composition of leaf water may contain information on transport pathways beyond the xylem, through differences in the development of gradients in enrichment within the various pathways. Subsequent testing of this suggestion provided ambiguous results and even questioned the existence of gradients in enrichment within the mesophyll. In this review, we bring together recent theoretical developments in understanding leaf water transport pathways and stable isotope theory to map a path for future work into understanding pathways of water transport and leaf water stable isotope composition. We emphasize the need for a spatially, anatomically and isotopically explicit model of leaf water transport. © 2016 John Wiley & Sons Ltd.

  10. From leaf to whole-plant water use efficiency (WUE in complex canopies: Limitations of leaf WUE as a selection target

    Directory of Open Access Journals (Sweden)

    Hipólito Medrano

    2015-06-01

    Full Text Available Plant water use efficiency (WUE is becoming a key issue in semiarid areas, where crop production relies on the use of large volumes of water. Improving WUE is necessary for securing environmental sustainability of food production in these areas. Given that climate change predictions include increases in temperature and drought in semiarid regions, improving crop WUE is mandatory for global food production. WUE is commonly measured at the leaf level, because portable equipment for measuring leaf gas exchange rates facilitates the simultaneous measurement of photosynthesis and transpiration. However, when those measurements are compared with daily integrals or whole-plant estimates of WUE, the two sometimes do not agree. Scaling up from single-leaf to whole-plant WUE was tested in grapevines in different experiments by comparison of daily integrals of instantaneous water use efficiency [ratio between CO2 assimilation (AN and transpiration (E; AN/E] with midday AN/E measurements, showing a low correlation, being worse with increasing water stress. We sought to evaluate the importance of spatial and temporal variation in carbon and water balances at the leaf and plant levels. The leaf position (governing average light interception in the canopy showed a marked effect on instantaneous and daily integrals of leaf WUE. Night transpiration and respiration rates were also evaluated, as well as respiration contributions to total carbon balance. Two main components were identified as filling the gap between leaf and whole plant WUE: the large effect of leaf position on daily carbon gain and water loss and the large flux of carbon losses by dark respiration. These results show that WUE evaluation among genotypes or treatments needs to be revised.

  11. Leaf anatomical traits determine the 18O enrichment of leaf water in coastal halophytes

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    Liang, J.; Lin, G., Sr.; Sternberg, L. O.

    2017-12-01

    Foliar anatomical adaptations to high-salinity environment in mangroves may be recorded by leaf water isotopes. Recent studies observed that a few mangrove species have lower 18O enrichment of leaf water (ΔL) relative to source water than the adjacent terrestrial trees, but what factors actually control this phenomenon is still disputable at present. To resolve this issue, we collected 15 species of true mangrove plants, 14 species of adjacent freshwater trees and 4 species of semi-mangrove plants at five study sites on the southeastern coast of China. Leaf stomatal density and pore size, water content, ΔL and other related leaf physiological traits were determined for the selected leaves of these plants. Our results confirmed that ΔL values of mangroves were generally 3 4 ‰ lower than those of the adjacent freshwater or semi-mangrove species. Higher leaf water per area (LWC) and lower leaf stomatal density (LS) of mangroves played co-dominant roles in lowering ΔL through elongating effective leaf mixing length by about 20%. The Péclet model incorporated by LWC and LS performed well in predicting ΔL. The demonstrated general law between leaf anatomy and ΔL in this paper based on a large pool of species bridges the gap between leaf functional traits and metabolic proxies derived ΔL, which will have considerable potential applications in vegetation succession and reconstruction of paleoclimate research.

  12. Comparison of dwarf bamboos (Indocalamus sp.) leaf parameters to determine relationship between spatial density of plants and total leaf area per plant.

    Science.gov (United States)

    Shi, Pei-Jian; Xu, Qiang; Sandhu, Hardev S; Gielis, Johan; Ding, Yu-Long; Li, Hua-Rong; Dong, Xiao-Bo

    2015-10-01

    The relationship between spatial density and size of plants is an important topic in plant ecology. The self-thinning rule suggests a -3/2 power between average biomass and density or a -1/2 power between stand yield and density. However, the self-thinning rule based on total leaf area per plant and density of plants has been neglected presumably because of the lack of a method that can accurately estimate the total leaf area per plant. We aimed to find the relationship between spatial density of plants and total leaf area per plant. We also attempted to provide a novel model for accurately describing the leaf shape of bamboos. We proposed a simplified Gielis equation with only two parameters to describe the leaf shape of bamboos one model parameter represented the overall ratio of leaf width to leaf length. Using this method, we compared some leaf parameters (leaf shape, number of leaves per plant, ratio of total leaf weight to aboveground weight per plant, and total leaf area per plant) of four bamboo species of genus Indocalamus Nakai (I. pedalis (Keng) P.C. Keng, I. pumilus Q.H. Dai and C.F. Keng, I. barbatus McClure, and I. victorialis P.C. Keng). We also explored the possible correlation between spatial density and total leaf area per plant using log-linear regression. We found that the simplified Gielis equation fit the leaf shape of four bamboo species very well. Although all these four species belonged to the same genus, there were still significant differences in leaf shape. Significant differences also existed in leaf area per plant, ratio of leaf weight to aboveground weight per plant, and leaf length. In addition, we found that the total leaf area per plant decreased with increased spatial density. Therefore, we directly demonstrated the self-thinning rule to improve light interception.

  13. Seasonality of Leaf Carbon Isotopic Composition and Leaf Water Isotopic Enrichment in a Mixed Evergreen Forest in Southern California

    Science.gov (United States)

    Santiago, L. S.; Sickman, J. O.; Goulden, M.; DeVan, C.; Pasquini, S. C.; Pivovaroff, A. L.

    2011-12-01

    Leaf carbon isotopic composition and leaf water isotopic enrichment reflect physiological processes and are important for linking local and regional scale processes to global patterns. We investigated how seasonality affects the isotopic composition of bulk leaf carbon, leaf sugar carbon, and leaf water hydrogen under a Mediterranean climate. Leaf and stem samples were collected monthly from four tree species (Calocedrus decurrens, Pinus lambertiana, Pinus ponderosa, and Quercus chrysolepis) at the James San Jacinto Mountain Reserve in southern California. Mean monthly bulk leaf carbon isotopic composition varied from -34.5 % in P. ponderosa to -24.7 % in P. lambertiana and became more depleted in 13C from the spring to the summer. Mean monthly leaf sugar varied from -29.3 % in P. ponderosa to -21.8 % in P. lambertiana and was enriched in 13C during the winter, spring and autumn, but depleted during the mid-summer. Leaf water hydrogen isotopic composition was 28.4 to 68.8 % more enriched in deuterium than source water and this enrichment was greater as seasonal drought progressed. These data indicate that leaf carbon and leaf water hydrogen isotopic composition provide sensitive measures that connect plant physiological processes to short-term climatic variability.

  14. A hairy-leaf gene, BLANKET LEAF, of wild Oryza nivara increases photosynthetic water use efficiency in rice.

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    Hamaoka, Norimitsu; Yasui, Hideshi; Yamagata, Yoshiyuki; Inoue, Yoko; Furuya, Naruto; Araki, Takuya; Ueno, Osamu; Yoshimura, Atsushi

    2017-12-01

    High water use efficiency is essential to water-saving cropping. Morphological traits that affect photosynthetic water use efficiency are not well known. We examined whether leaf hairiness improves photosynthetic water use efficiency in rice. A chromosome segment introgression line (IL-hairy) of wild Oryza nivara (Acc. IRGC105715) with the genetic background of Oryza sativa cultivar 'IR24' had high leaf pubescence (hair). The leaf hairs developed along small vascular bundles. Linkage analysis in BC 5 F 2 and F 3 populations showed that the trait was governed by a single gene, designated BLANKET LEAF (BKL), on chromosome 6. IL-hairy plants had a warmer leaf surface in sunlight, probably due to increased boundary layer resistance. They had a lower transpiration rate under moderate and high light intensities, resulting in higher photosynthetic water use efficiency. Introgression of BKL on chromosome 6 from O. nivara improved photosynthetic water use efficiency in the genetic background of IR24.

  15. Leaf hydraulic conductance declines in coordination with photosynthesis, transpiration and leaf water status as soybean leaves age regardless of soil moisture

    Science.gov (United States)

    Locke, Anna M.; Ort, Donald R.

    2014-01-01

    Photosynthesis requires sufficient water transport through leaves for stomata to remain open as water transpires from the leaf, allowing CO2 to diffuse into the leaf. The leaf water needs of soybean change over time because of large microenvironment changes over their lifespan, as leaves mature in full sun at the top of the canopy and then become progressively shaded by younger leaves developing above. Leaf hydraulic conductance (K leaf), a measure of the leaf’s water transport capacity, can often be linked to changes in microenvironment and transpiration demand. In this study, we tested the hypothesis that K leaf would decline in coordination with transpiration demand as soybean leaves matured and aged. Photosynthesis (A), stomatal conductance (g s) and leaf water potential (Ψleaf) were also measured at various leaf ages with both field- and chamber-grown soybeans to assess transpiration demand. K leaf was found to decrease as soybean leaves aged from maturity to shading to senescence, and this decrease was strongly correlated with midday A. Decreases in K leaf were further correlated with decreases in g s, although the relationship was not as strong as that with A. Separate experiments investigating the response of K leaf to drought demonstrated no acclimation of K leaf to drought conditions to protect against cavitation or loss of g s during drought and confirmed the effect of leaf age in K leaf observed in the field. These results suggest that the decline of leaf hydraulic conductance as leaves age keeps hydraulic supply in balance with demand without K leaf becoming limiting to transpiration water flux. PMID:25281701

  16. Ozone exposure affects leaf wettability and tree water balance

    NARCIS (Netherlands)

    Schreuder, M.D.J.; Hove, van L.W.A.; Brewer, C.A.

    2001-01-01

    Relatively little is known about the influences of growing-season background ozone (O3) concentrations on leaf cuticles and foliar water loss. Using fumigation chambers, leaf wettability and foliar water loss were studied in two poplar species, Populus nigra and P. euramericana, and a conifer,

  17. [Spectrum Variance Analysis of Tree Leaves Under the Condition of Different Leaf water Content].

    Science.gov (United States)

    Wu, Jian; Chen, Tai-sheng; Pan, Li-xin

    2015-07-01

    Leaf water content is an important factor affecting tree spectral characteristics. So Exploring the leaf spectral characteristics change rule of the same tree under the condition of different leaf water content and the spectral differences of different tree leaves under the condition of the same leaf water content are not only the keys of hyperspectral vegetation remote sensing information identification but also the theoretical support of research on vegetation spectrum change as the differences in leaf water content. The spectrometer was used to observe six species of tree leaves, and the reflectivity and first order differential spectrum of different leaf water content were obtained. Then, the spectral characteristics of each tree species leaves under the condition of different leaf water content were analyzed, and the spectral differences of different tree species leaves under the condition of the same leaf water content were compared to explore possible bands of the leaf water content identification by hyperspectral remote sensing. Results show that the spectra of each tree leaf have changed a lot with the change of the leaf water content, but the change laws are different. Leaf spectral of different tree species has lager differences in some wavelength range under the condition of same leaf water content, and it provides some possibility for high precision identification of tree species.

  18. Ozone and sulphur dioxide effects on leaf water potential of Petunia

    Energy Technology Data Exchange (ETDEWEB)

    Elkiey, T.; Ormrod, D.P.

    1979-01-01

    Three cultivars of Petunia hydrida Vilm., of differing ozone visible injury sensitivity, were exposed to 40 parts per hundred million (pphm) ozone and/or 80 pphm SO/sub 2/ for 4 h to study the relationships of leaf water potential, pollutant exposure, and cultivar sensitivity. Ozone substantially decreased leaf water potential in cv White Cascade but not in cv Capri or White Magic. Sulphur dioxide did not affect leaf water potential but delayed ozone-induced changes. Cultivar sensitivity to ozone-induced changes in leaf water potential was not related to cultivar sensitivity to ozone-induced visible injury.

  19. Interacting Effects of Leaf Water Potential and Biomass on Vegetation Optical Depth

    Science.gov (United States)

    Momen, M.; Wood, J. D.; Novick, K. A.; Pockman, W.; Konings, A. G.

    2017-12-01

    Remotely-sensed microwave observations of vegetation optical depth (VOD) have been widely used to examine vegetation responses to climate. Such studies have alternately found that VOD is sensitive to both biomass and canopy water content. However, the relative impacts of changes in phenology or water stress on VOD have not been disentangled. In particular, understanding whether leaf water potential (LWP) affects VOD may permit the assimilation of satellite observations into new large-scale plant hydraulic models. Despite extensive validation of the relationship between satellite-derived VOD estimates and vegetation density, relatively few studies have explicitly sought to validate the sensitivity of VOD to canopy water status, and none have studied the effect of variations in LWP on VOD. In this work, we test the sensitivity of VOD to variations in LWP, and present a conceptual framework which relates VOD to a combination of leaf water potential and total biomass including leaves, whose dynamics can be measured through leaf area index, and woody biomass. We used in-situ measurements of LWP data to validate the conceptual model in mixed deciduous forests in Indiana and Missouri, as well as a pinion-juniper woodland in New Mexico. Observed X-band VOD from the AMSR-E and AMSR2 satellites showed dynamics similar to those reconstructed VOD signals based on the new conceptual model which employs in-situ LWP data (R2=0.60-0.80). Because LWP data are not available at global scales, we further estimated ecosystem LWP based on remotely sensed surface soil moisture to better understand the sensitivity of VOD across ecosystems. At the global scale, incorporating a combination of biomass and water potential in the reconstructed VOD signal increased correlations with VOD about 15% compared to biomass alone and about 30% compared to water potential alone. In wetter regions with denser and taller canopy heights, VOD has a higher correlation with leaf area index than with water

  20. MONITORING ON PLANT LEAF WATER POTENTIAL USING NIR SPECTROSCOPY FOR WATER STRESS MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Diding Suhandy

    2012-12-01

    Full Text Available The performance of the calibration model with temperature compensation for on-plant leaf water potential (LWP determination in tomato plants was evaluated. During a cycle of water stress, the on-plant LWP measurement was conducted. The result showed that the LWP values under water stress and recovery from water stress could be monitored well. It showed that a real time monitoring of the LWP values using NIR spectroscopy could be possible.   Keywords: water stress, real time monitoring of leaf water potential, NIR spectroscopy, plant response-based

  1. Response of nutrients, minerals, antioxidant leaf pigments, vitamins, polyphenol, flavonoid and antioxidant activity in selected vegetable amaranth under four soil water content.

    Science.gov (United States)

    Sarker, Umakanta; Oba, Shinya

    2018-06-30

    Four selected vegetable amaranths were grown under four soil water content to evaluate their response in nutrients, minerals, antioxidant leaf pigments, vitamins, polyphenol, flavonoid and total antioxidant activity (TAC). Vegetable amaranth was significantly affected by variety, soil water content and variety × soil water content interactions for all the traits studied. Increase in water stress, resulted in significant changes in proximate compositions, minerals (macro and micro), leaf pigments, vitamin, total polyphenol content (TPC), and total flavonoid content (TFC) of vegetable amaranth. Accessions VA14 and VA16 performed better for all the traits studied. Correlation study revealed a strong antioxidant scavenging activity of leaf pigments, ascorbic acid, TPC and TFC. Vegetable amaranth can tolerate soil water stress without compromising the high quality of the final product in terms of nutrients and antioxidant profiles. Therefore, it could be a promising alternative crop in semi-arid and dry areas and also during dry seasons. Copyright © 2018. Published by Elsevier Ltd.

  2. Estimates of Leaf Relative Water Content from Optical Polarization Measurements

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    Dahlgren, R. P.; Vanderbilt, V. C.; Daughtry, C. S. T.

    2017-12-01

    Remotely sensing the water status of plant canopies remains a long term goal of remote sensing research. Existing approaches to remotely sensing canopy water status, such as the Crop Water Stress Index (CWSI) and the Equivalent Water Thickness (EWT), have limitations. The CWSI, based upon remotely sensing canopy radiant temperature in the thermal infrared spectral region, does not work well in humid regions, requires estimates of the vapor pressure deficit near the canopy during the remote sensing over-flight and, once stomata close, provides little information regarding the canopy water status. The EWT is based upon the physics of water-light interaction in the 900-2000nm spectral region, not plant physiology. Our goal, development of a remote sensing technique for estimating plant water status based upon measurements in the VIS/NIR spectral region, would potentially provide remote sensing access to plant dehydration physiology - to the cellular photochemistry and structural changes associated with water deficits in leaves. In this research, we used optical, crossed polarization filters to measure the VIS/NIR light reflected from the leaf interior, R, as well as the leaf transmittance, T, for 78 corn (Zea mays) and soybean (Glycine max) leaves having relative water contents (RWC) between 0.60 and 0.98. Our results show that as RWC decreases R increases while T decreases. Our results tie R and T changes in the VIS/NIR to leaf physiological changes - linking the light scattered out of the drying leaf interior to its relative water content and to changes in leaf cellular structure and pigments. Our results suggest remotely sensing the physiological water status of a single leaf - and perhaps of a plant canopy - might be possible in the future.

  3. Estimating the total leaf area of the green dwarf coconut tree (Cocos nucifera L.

    Directory of Open Access Journals (Sweden)

    Sousa Elias Fernandes de

    2005-01-01

    Full Text Available Leaf area has significant effect on tree transpiration, and its measurement is important to many study areas. This work aimed at developing a non-destructive, practical, and empirical method to estimate the total leaf area of green dwarf coconut palms (Cocos nucifera L. in plantations located at the northern region of Rio de Janeiro state, Brazil. A mathematical model was developed to estimate total leaf area values (TLA as function of the average lengths of the last three leaf raquis (LR3, and of the number of leaves in the canopy (NL. The model has satisfactory degree of accuracy for agricultural engineering purposes.

  4. Chemical Composition and Water Permeability of Fruit and Leaf Cuticles of Olea europaea L.

    Science.gov (United States)

    Huang, Hua; Burghardt, Markus; Schuster, Ann-Christin; Leide, Jana; Lara, Isabel; Riederer, Markus

    2017-10-11

    The plant cuticle, protecting against uncontrolled water loss, covers olive (Olea europaea) fruits and leaves. The present study describes the organ-specific chemical composition of the cuticular waxes and the cutin and compares three developmental stages of fruits (green, turning, and black) with the leaf surface. Numerous organ-specific differences, such as the total coverage of cutin monomeric components (1034.4 μg cm -2 and 630.5 μg cm -2 ) and the cuticular waxes (201.6 μg cm -2 and 320.4 μg cm -2 ) among all three fruit stages and leaves, respectively, were detected. Water permeability as the main cuticular function was 5-fold lower in adaxial leaf cuticles (2.1 × 10 -5 m s -1 ) in comparison to all three fruit stages (9.5 × 10 -5 m s -1 ). The three fruit developmental stages have the same cuticular water permeability. It is hypothesized that a higher weighted average chain length of the acyclic cuticular components leads to a considerably lower permeability of the leaf as compared to the fruit cuticle.

  5. Final report on the safety assessment of AloeAndongensis Extract, Aloe Andongensis Leaf Juice,aloe Arborescens Leaf Extract, Aloe Arborescens Leaf Juice, Aloe Arborescens Leaf Protoplasts, Aloe Barbadensis Flower Extract, Aloe Barbadensis Leaf, Aloe Barbadensis Leaf Extract, Aloe Barbadensis Leaf Juice,aloe Barbadensis Leaf Polysaccharides, Aloe Barbadensis Leaf Water, Aloe Ferox Leaf Extract, Aloe Ferox Leaf Juice, and Aloe Ferox Leaf Juice Extract.

    Science.gov (United States)

    2007-01-01

    Plant materials derived from the Aloe plant are used as cosmetic ingredients, including Aloe Andongensis Extract, Aloe Andongensis Leaf Juice, Aloe Arborescens Leaf Extract, Aloe Arborescens Leaf Juice, Aloe Arborescens Leaf Protoplasts, Aloe Barbadensis Flower Extract, Aloe Barbadensis Leaf, Aloe Barbadensis Leaf Extract, Aloe Barbadensis Leaf Juice, Aloe Barbadensis Leaf Polysaccharides, Aloe Barbadensis Leaf Water, Aloe Ferox Leaf Extract, Aloe Ferox Leaf Juice, and Aloe Ferox Leaf Juice Extract. These ingredients function primarily as skin-conditioning agents and are included in cosmetics only at low concentrations. The Aloe leaf consists of the pericyclic cells, found just below the plant's skin, and the inner central area of the leaf, i.e., the gel, which is used for cosmetic products. The pericyclic cells produce a bitter, yellow latex containing a number of anthraquinones, phototoxic compounds that are also gastrointestinal irritants responsible for cathartic effects. The gel contains polysaccharides, which can be acetylated, partially acetylated, or not acetylated. An industry established limit for anthraquinones in aloe-derived material for nonmedicinal use is 50 ppm or lower. Aloe-derived ingredients are used in a wide variety of cosmetic product types at concentrations of raw material that are 0.1% or less, although can be as high as 20%. The concentration of Aloe in the raw material also may vary from 100% to a low of 0.0005%. Oral administration of various anthraquinone components results in a rise in their blood concentrations, wide systemic distribution, accumulation in the liver and kidneys, and excretion in urine and feces; polysaccharide components are distributed systemically and metabolized into smaller molecules. aloe-derived material has fungicidal, antimicrobial, and antiviral activities, and has been effective in wound healing and infection treatment in animals. Aloe barbadensis (also known as Aloe vera)-derived ingredients were not toxic

  6. Leaf water stress detection utilizing thematic mapper bands 3, 4 and 5 in soybean plants

    Science.gov (United States)

    Holben, B. N.; Schutt, J. B.; Mcmurtrey, J., III

    1983-01-01

    The total and diffuse radiance responses of Thematic Mapper bands 3 (0.63-0.69 microns), 4 (0.76-0.90 microns), and 5 (1.55-1.75 microns) to water stress in a soybean canopy are compared. Polarization measurements were used to separate the total from the diffuse reflectance; the reflectances were compared statistically at a variety of look angles at 15 min intervals from about 09.00 until 14.00 hrs EST. The results suggest that remotely sensed data collected in the photographic infrared region (TM4) are sensitive to leaf water stress in a 100 percent canopy cover of soybeans, and that TM3 is less sensitive than TM4 for detection of reversible foliar water stress. The mean values of TM5 reflectance data show similar trends to TM4. The primary implication of this study is that remote sensing of water stress in green plant canopies is possible in TM4 from ground-based observations primarily through the indirect link of leaf geometry.

  7. Temporal versus spatial variation in leaf reflectance under changing water stress conditions

    Science.gov (United States)

    Cohen, Warren B.

    1991-01-01

    Leaf reflectance changes associated with changes in water stress were analyzed in two separate experiments. Results indicate that the variation in reflectance among collections of leaves of a given species all at the same level of water stress is at least as great as the variation in reflectance associated with changes in water stress for a given leaf collection of that species. The implications is that results from leaf reflectance-water stress studies have only limited applicability to the remote sensing of plant canopy water stress.

  8. Estimating Leaf Water Potential of Giant Sequoia Trees from Airborne Hyperspectral Imagery

    Science.gov (United States)

    Francis, E. J.; Asner, G. P.

    2015-12-01

    Recent drought-induced forest dieback events have motivated research on the mechanisms of tree survival and mortality during drought. Leaf water potential, a measure of the force exerted by the evaporation of water from the leaf surface, is an indicator of plant water stress and can help predict tree mortality in response to drought. Scientists have traditionally measured water potentials on a tree-by-tree basis, but have not been able to produce maps of tree water potential at the scale of a whole forest, leaving forest managers unaware of forest drought stress patterns and their ecosystem-level consequences. Imaging spectroscopy, a technique for remote measurement of chemical properties, has been used to successfully estimate leaf water potentials in wheat and maize crops and pinyon-pine and juniper trees, but these estimates have never been scaled to the canopy level. We used hyperspectral reflectance data collected by the Carnegie Airborne Observatory (CAO) to map leaf water potentials of giant sequoia trees (Sequoiadendron giganteum) in an 800-hectare grove in Sequoia National Park. During the current severe drought in California, we measured predawn and midday leaf water potentials of 48 giant sequoia trees, using the pressure bomb method on treetop foliage samples collected with tree-climbing techniques. The CAO collected hyperspectral reflectance data at 1-meter resolution from the same grove within 1-2 weeks of the tree-level measurements. A partial least squares regression was used to correlate reflectance data extracted from the 48 focal trees with their water potentials, producing a model that predicts water potential of giant sequoia trees. Results show that giant sequoia trees can be mapped in the imagery with a classification accuracy of 0.94, and we predicted the water potential of the mapped trees to assess 1) similarities and differences between a leaf water potential map and a canopy water content map produced from airborne hyperspectral data, 2

  9. Seasonal changes in plant-water relations influence patterns of leaf display in Miombo woodlands: evidence of water conservative strategies.

    Science.gov (United States)

    Vinya, Royd; Malhi, Yadvinder; Brown, Nick D; Fisher, Joshua B; Brodribb, Timothy; Aragão, Luiz E O C

    2018-06-15

    Water availability has frequently been linked to seasonal leaf display in seasonally dry ecosystems, but there have been few ecohydrological investigations of this link. Miombo woodland is a dominant seasonally dry tropical forest ecosystem type in southern Africa; however, there are few data on the relationship between seasonal dynamics in plant-water relations and patterns of leaf display for Miombo woodland. Here we investigate this relationship among nine key Miombo woodland tree species differing in drought tolerance ability and leaf phenology. Results of this study showed that seasonal patterns of leaf phenology varied significantly with seasonal changes in stem water relations among the nine species. Leaf shedding coincided with the attainment of seasonal minimum stem water potential. Leaf flush occurred following xylem rehydration at the peak of the dry season suggesting that endogenous plant factors play a pivotal role in seasonal leaf display in this forest type. Drought-tolerant deciduous species suffered significantly higher seasonal losses in xylem hydraulic conductivity than the drought-intolerant semi-evergreen tree species (P water stress in seasonally dry tropical forests selects for water conservative traits that protect the vulnerable xylem transport system. Therefore, seasonal rhythms in xylem transport dictate patterns of leaf display in seasonally dry tropical forests.

  10. Leaf habit and woodiness regulate different leaf economy traits at a given nutrient supply.

    Science.gov (United States)

    Ordoñez, Jenny C; van Bodegom, Peter M; Witte, Jan-Philip M; Bartholomeus, Ruud P; van Dobben, Han F; Aerts, Rien

    2010-11-01

    The large variation in the relationships between environmental factors and plant traits observed in natural communities exemplifies the alternative solutions that plants have developed in response to the same environmental limitations. Qualitative attributes, such as growth form, woodiness, and leaf habit can be used to approximate these alternative solutions. Here, we quantified the extent to which these attributes affect leaf trait values at a given resource supply level, using measured plant traits from 105 different species (254 observations) distributed across 50 sites in mesic to wet plant communities in The Netherlands. For each site, soil total N, soil total P, and water supply estimates were obtained by field measurements and modeling. Effects of growth forms, woodiness, and leaf habit on relations between leaf traits (SLA, specific leaf area; LNC, leaf nitrogen concentration; and LPC, leaf phosphorus concentration) vs. nutrient and water supply were quantified using maximum-likelihood methods and Bonferroni post hoc tests. The qualitative attributes explained 8-23% of the variance within sites in leaf traits vs. soil fertility relationships, and therefore they can potentially be used to make better predictions of global patterns of leaf traits in relation to nutrient supply. However, at a given soil fertility, the strength of the effect of each qualitative attribute was not the same for all leaf traits. These differences may imply a differential regulation of the leaf economy traits at a given nutrient supply, in which SLA and LPC seem to be regulated in accordance to changes in plant size and architecture while LNC seems to be primarily regulated at the leaf level by factors related to leaf longevity.

  11. Effect of weed control treatments on total leaf area of plantation black walnut (Juglans nigra)

    Science.gov (United States)

    Jason Cook; Michael R. Saunders

    2013-01-01

    Determining total tree leaf area is necessary for describing tree carbon balance, growth efficiency, and other measures used in tree-level and stand-level physiological growth models. We examined the effects of vegetation control methods on the total leaf area of sapling-size plantation black walnut trees using allometric approaches. We found significant differences in...

  12. Assessment of nutritional quality of water hyacinth leaf protein concentrate

    Directory of Open Access Journals (Sweden)

    Oyeyemi Adeyemi

    2016-09-01

    Full Text Available This study was embarked upon to convert water hyacinth, an environmental nuisance, to a natural resource for economic development. Water hyacinth leaf protein concentrate (WHLPC was extracted in edible form and determination of its physicochemical characteristics, total alkaloids and phenolic compounds was done. Analysis of proximate composition and amino acid profile of the WHLPC was also done. The level of heavy metals (mg/kg in WHLPC was found to be Cd (0.02 ± 0.001, Cr (0.13 ± 0.001, Pd (0.003 ± 0.001 and Hg (0.02 ± 0.001 while concentrations of Pb, Pt, Sn, Fe, Cu, Zn, Ni and Co were found to be 0.001 ± 0.00. Level of all heavy metals was found to be within safe limit. Proximate analysis revealed that protein in WHLPC accounted for 50% of its nutrients, carbohydrate accounted for 33% of its nutrients while fat, ash and fibre made up the remaining nutrients. Amino acid analysis showed that WHLPC contained 17 out of 20 common amino acids, particularly, Phe (3.67%, Leu (5.01%. Level of total alkaloids and phenolic compounds was 16.6 mg/kg and 6.0 mg/kg respectively. Evidence from this study suggests that WHLPC is a good source of leaf protein concentrate (LPC; it is nutritious and acutely non toxic.

  13. Variation in leaf water delta D and delta 18O values during the evapotranspiration process

    International Nuclear Information System (INIS)

    Leopoldo, P.R.; Foloni, L.L.

    1984-01-01

    A theoretical model was developed to evaluate leaf water delta D and delta 18 O variation in relation to: leaf temperature, relative humidity converted to leaf temperature and delta D and delta 18 O values of atmospheric water vapour and soil water. (M.A.C.) [pt

  14. On the use of leaf spectral indices to assess water status and photosynthetic limitations in Olea europaea L. during water-stress and recovery.

    Science.gov (United States)

    Sun, Pengsen; Wahbi, Said; Tsonev, Tsonko; Haworth, Matthew; Liu, Shirong; Centritto, Mauro

    2014-01-01

    Diffusional limitations to photosynthesis, relative water content (RWC), pigment concentrations and their association with reflectance indices were studied in olive (Olea europaea) saplings subjected to water-stress and re-watering. RWC decreased sharply as drought progressed. Following rewatering, RWC gradually increased to pre-stress values. Photosynthesis (A), stomatal conductance (gs), mesophyll conductance (gm), total conductance (gt), photochemical reflectance index (PRI), water index (WI) and relative depth index (RDI) closely followed RWC. In contrast, carotenoid concentration, the carotenoid to chlorophyll ratio, water content reflectance index (WCRI) and structural independent pigment index (SIPI) showed an opposite trend to that of RWC. Photosynthesis scaled linearly with leaf conductance to CO2; however, A measured under non-photorespiratory conditions (A1%O2) was approximately two times greater than A measured at 21% [O2], indicating that photorespiration likely increased in response to drought. A1%O2 also significantly correlated with leaf conductance parameters. These relationships were apparent in saturation type curves, indicating that under non-photorespiratory conditions, CO2 conductance was not the major limitations to A. PRI was significant correlated with RWC. PRI was also very sensitive to pigment concentrations and photosynthesis, and significantly tracked all CO2 conductance parameters. WI, RDI and WCRI were all significantly correlated with RWC, and most notably to leaf transpiration. Overall, PRI correlated more closely with carotenoid concentration than SIPI; whereas WI tracked leaf transpiration more effectively than RDI and WCRI. This study clearly demonstrates that PRI and WI can be used for the fast detection of physiological traits of olive trees subjected to water-stress.

  15. Disruption of mycorrhizal extraradical mycelium and changes in leaf water status and soil aggregate stability in rootbox-grown trifoliate orange

    Directory of Open Access Journals (Sweden)

    Ying-Ning eZou

    2015-03-01

    Full Text Available Arbuscular mycorrhizas possess well developed extraradical mycelium (ERM network that enlarge the surrounding soil for better acquisition of water and nutrients, besides soil aggregation. Distinction in ERM functioning was studied under a rootbox system, which consisted of root+hyphae and root-free hyphae compartments separated by 37-μm nylon mesh with an air gap. Trifoliate orange (Poncirus trifoliata seedlings were inoculated with Funneliformis mosseae in root+hyphae compartment, and the ERM network was established between the two compartments. The ERM network of air gap was disrupted before 8 h of the harvest (one time disruption or multiple disruptions during seedlings acclimation. Our results showed that mycorrhizal inoculation induced a significant increase in growth (plant height, stem diameter, and leaf, stem, and root biomass and physiological characters (leaf relative water content, leaf water potential, and transpiration rate, irrespective of ERM status. Easily-extractable glomalin-related soil protein (EE-GRSP and total GRSP (T-GRSP concentration and mean weight diameter (MWD, an indicator of soil aggregate stability were significantly higher in mycorrhizosphere of root+hyphae and root-free hyphae compartments than non-mycorrhizosphere. One time disruption of ERM network did not influence plant growth and soil properties but only notably decreased leaf water. Periodical disruption of ERM network at weekly interval markedly inhibited the mycorrhizal roles on plant growth, leaf water, GRSP production, and MWD in root+hyphae and hyphae chambers. EE-GRSP was the most responsive GRSP fraction to changes in leaf water and MWD under root+hyphae and hyphae conditions. It suggests that effect of peridical disruption of ERM network was more impactful than one-time disruption of ERM network with regard to leaf water, plant growth, and aggregate stability responses, thereby, implying ERM network aided in developing the host plant metabolically

  16. Total Lactic Acid Bacteria (LAB), Antioxidant Activity, and Acceptance of Synbiotic Yoghurt with Binahong Leaf Extract (Anredera cordifolia (Ten.) Steenis)

    Science.gov (United States)

    Lestari, R. P.; Nissa, C.; Afifah, D. N.; Anjani, G.; Rustanti, N.

    2018-02-01

    Alternative treatment for metabolic syndrome can be done by providing a diet consist of functional foods or beverages. Synbiotic yoghurt containing binahong leaf extract which high in antioxidant, total LAB and fiber can be selected to reduce the risk of metabolic syndrome. The effect of binahong leaf extract in synbiotic yoghurt against total LAB, antioxidant activity, and acceptance were analyzed. The experiment was done with complete randomized design with addition of binahong leaf extract 0% (control); 0.12%; 0.25%; 0.5% in synbiotic yoghurt. Analysis of total LAB using Total Plate Count test, antioxidant activity using DPPH, and acceptance were analyzed by hedonic test. The addition of binahong leaf extract in various doses in synbiotic yoghurt decreased total LAB without significant effect (p=0,145). There was no effect of addition binahong leaf extract on antioxidant activity (p=0,297). The addition of binahong leaf extract had an effect on color, but not on aroma, texture and taste. The best result was yoghurt synbiotic with addition of 0,12% binahong leaf extract. Conclusion of the research was the addition of binahong leaf extract to synbiotic yogurt did not significantly affect total LAB, antioxidant activity, aroma, texture and taste; but had a significant effect on color.

  17. [Seasonal differences in the leaf hydraulic conductance of mature Acacia mangium in response to its leaf water use and photosynthesis].

    Science.gov (United States)

    Zhao, Ping; Sun, Gu-Chou; Ni, Guang-Yan; Zeng, Xiao-Ping

    2013-01-01

    In this study, measurements were made on the leaf water potential (psi1), stomatal conductance (g(s)), transpiration rate, leaf area index, and sapwood area of mature Acacia mangium, aimed to understand the relationships of the leaf hydraulic conductance (K1) with the leaf water use and photosynthetic characteristics of the A. mangium in wet season (May) and dry season (November). The ratio of sapwood area to leaf area (A(sp)/A(cl)) of the larger trees with an average height of 20 m and a diameter at breast height (DBH) of 0.26 m was 8.5% higher than that of the smaller trees with an average height of 14.5 m and a DBH of 0.19 m, suggesting that the larger trees had a higher water flux in their leaf xylem, which facilitated the water use of canopy leaf. The analysis on the vulnerability curve of the xylem showed that when the K1 decreased by 50%, the psi1 in wet season and dry season was -1.41 and -1.55 MPa, respectively, and the vulnerability of the xylem cavitation was higher in dry season than in wet season. The K1 peak value in wet season and dry season was 5.5 and 4.5 mmol x m(-2) x s(-1) x MPa(-1), and the maximum transpiration rate (T(r max)) was 3.6 and 1.8 mmol x m(-2) x s(-1), respectively. Both the K1 and T(r max), were obviously higher in wet season than in dry season. Within a day, the K1 and T(r), fluctuated many times, reflecting the reciprocated cycle of the xylem cavitation and refilling. The leaf stomatal closure occurred when the K1 declined over 50% or the psi1 reached -1.6 MPa. The g(s) would be maintained at a high level till the K1 declined over 50%. The correlation between the hydraulic conductance and photosynthetic rate was more significant in dry season than in wet season. The loss of leaf hydraulic conductance induced by seasonal change could be the causes of the decrease of T(r) and CO2 gas exchange.

  18. On the controls of leaf-water oxygen isotope ratios in the atmospheric Crassulacean acid metabolism epiphyte Tillandsia usneoides.

    Science.gov (United States)

    Helliker, Brent R

    2011-04-01

    Previous theoretical work showed that leaf-water isotope ratio (δ(18)O(L)) of Crassulacean acid metabolism epiphytes was controlled by the δ(18)O of atmospheric water vapor (δ(18)O(a)), and observed δ(18)O(L) could be explained by both a non-steady-state model and a "maximum enrichment" steady-state model (δ(18)O(L-M)), the latter requiring only δ(18)O(a) and relative humidity (h) as inputs. δ(18)O(L), therefore, should contain an extractable record of δ(18)O(a). Previous empirical work supported this hypothesis but raised many questions. How does changing δ(18)O(a) and h affect δ(18)O(L)? Do hygroscopic trichomes affect observed δ(18)O(L)? Are observations of changes in water content required for the prediction of δ(18)O(L)? Does the leaf need to be at full isotopic steady state for observed δ(18)O(L) to equal δ(18)O(L-M)? These questions were examined with a climate-controlled experimental system capable of holding δ(18)O(a) constant for several weeks. Water adsorbed to trichomes required a correction ranging from 0.5‰ to 1‰. δ(18)O(L) could be predicted using constant values of water content and even total conductance. Tissue rehydration caused a transitory change in δ(18)O(L), but the consequent increase in total conductance led to a tighter coupling with δ(18)O(a). The non-steady-state leaf water models explained observed δ(18)O(L) (y = 0.93*x - 0.07; r(2) = 0.98) over a wide range of δ(18)O(a) and h. Predictions of δ(18)O(L-M) agreed with observations of δ(18)O(L) (y = 0.87*x - 0.99; r(2) = 0.92), and when h > 0.9, the leaf did not need to be at isotopic steady state for the δ(18)O(L-M) model to predict δ(18)O(L) in the Crassulacean acid metabolism epiphyte Tillandsia usneoides.

  19. Does shoot water status limit leaf expansion of nitrogen-deprived barley?

    Science.gov (United States)

    Dodd, I C; Munns, Rana; Passioura, J B

    2002-08-01

    The role of shoot water status in mediating the decline in leaf elongation rate of nitrogen (N)-deprived barley plants was assessed. Plants were grown at two levels of N supply, with or without the application of pneumatic pressure to the roots. Applying enough pressure (balancing pressure) to keep xylem sap continuously bleeding from the cut surface of a leaf allowed the plants to remain at full turgor throughout the experiments. Plants from which N was withheld required a greater balancing pressure during both day and night. This difference in balancing pressure was greater at high (2.0 kPa) than low (1.2 kPa) atmospheric vapour pressure deficit (VPD). Pressurizing the roots did not prevent the decline in leaf elongation rate induced by withholding N at either high or low VPD. Thus low shoot water status did not limit leaf growth of N-deprived plants.

  20. Linkage between canopy water storage and drop size distributions of leaf drips

    Science.gov (United States)

    Nanko, Kazuki; Watanabe, Ai; Hotta, Norifumi; Suzuki, Masakazu

    2013-04-01

    Differences in drop size distribution (DSD) of leaf drips among tree species have been estimated and physically interpreted to clarify the leaf drip generation process. Leaf drip generation experiments for nine species were conducted in an indoor location without foliage vibration using an automatic mist spray. Broad-leaved species produced a similar DSD among species whose leaves had a matte surface and a second similar DSD among species whose leaves had a coated surface. The matte broad leaves produced a larger and wider range of DSDs than the coated broad leaves. Coated coniferous needles had a wider range of DSDs than the coated broad leaves and different DSDs were observed for different species. The species with shorter dense needles generated a larger DSD. The leaf drip diameter was calculated through the estimation of a state of equilibrium of a hanging drop on the leaves based on physical theory. The calculations indicated that the maximum diameter of leaf drips was determined by the contact angle, and the range of DSDs was determined by the variation in contact length and the contact diameter at the hanging points. The results revealed that leaf drip DSD changed due to variations in leaf hydrophobicity, leaf roughness, leaf geometry and leaf inclination among the different tree species. This study allows the modelization of throughfall DSD. Furthermore, it indicates the possibility of interpreting canopy water processes from canopy water storage to drainage through the contact angle and leaf drip DSD. The part of this study is published in Nanko et al. (2013, Agric. Forest. Meteorol. 169, 74-84).

  1. Sugar and hexokinase suppress expression of PIP aquaporins and reduce leaf hydraulics that preserves leaf water potential.

    Science.gov (United States)

    Kelly, Gilor; Sade, Nir; Doron-Faigenboim, Adi; Lerner, Stephen; Shatil-Cohen, Arava; Yeselson, Yelena; Egbaria, Aiman; Kottapalli, Jayaram; Schaffer, Arthur A; Moshelion, Menachem; Granot, David

    2017-07-01

    Sugars affect central aspects of plant physiology, including photosynthesis, stomatal behavior and the loss of water through the stomata. Yet, the potential effects of sugars on plant aquaporins (AQPs) and water conductance have not been examined. We used database and transcriptional analyses, as well as cellular and whole-plant functional techniques to examine the link between sugar-related genes and AQPs. Database analyses revealed a high level of correlation between the expression of AQPs and that of sugar-related genes, including the Arabidopsis hexokinases 1 (AtHXK1). Increased expression of AtHXK1, as well as the addition of its primary substrate, glucose (Glc), repressed the expression of 10 AQPs from the plasma membrane-intrinsic proteins (PIP) subfamily (PIP-AQPs) and induced the expression of two stress-related PIP-AQPs. The osmotic water permeability of mesophyll protoplasts of AtHXK1-expressing plants and the leaf hydraulic conductance of those plants were significantly reduced, in line with the decreased expression of PIP-AQPs. Conversely, hxk1 mutants demonstrated a higher level of hydraulic conductance, with increased water potential in their leaves. In addition, the presence of Glc reduced leaf water potential, as compared with an osmotic control, indicating that Glc reduces the movement of water from the xylem into the mesophyll. The production of sugars entails a significant loss of water and these results suggest that sugars and AtHXK1 affect the expression of AQP genes and reduce leaf water conductance, to coordinate sugar levels with the loss of water through transpiration. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  2. Effect of Leaf Water Potential on Internal Humidity and CO2 Dissolution: Reverse Transpiration and Improved Water Use Efficiency under Negative Pressure.

    Science.gov (United States)

    Vesala, Timo; Sevanto, Sanna; Grönholm, Tiia; Salmon, Yann; Nikinmaa, Eero; Hari, Pertti; Hölttä, Teemu

    2017-01-01

    The pull of water from the soil to the leaves causes water in the transpiration stream to be under negative pressure decreasing the water potential below zero. The osmotic concentration also contributes to the decrease in leaf water potential but with much lesser extent. Thus, the surface tension force is approximately balanced by a force induced by negative water potential resulting in concavely curved water-air interfaces in leaves. The lowered water potential causes a reduction in the equilibrium water vapor pressure in internal (sub-stomatal/intercellular) cavities in relation to that over water with the potential of zero, i.e., over the flat surface. The curved surface causes a reduction also in the equilibrium vapor pressure of dissolved CO 2 , thus enhancing its physical solubility to water. Although the water vapor reduction is acknowledged by plant physiologists its consequences for water vapor exchange at low water potential values have received very little attention. Consequences of the enhanced CO 2 solubility to a leaf water-carbon budget have not been considered at all before this study. We use theoretical calculations and modeling to show how the reduction in the vapor pressures affects transpiration and carbon assimilation rates. Our results indicate that the reduction in vapor pressures of water and CO 2 could enhance plant water use efficiency up to about 10% at a leaf water potential of -2 MPa, and much more when water potential decreases further. The low water potential allows for a direct stomatal water vapor uptake from the ambient air even at sub-100% relative humidity values. This alone could explain the observed rates of foliar water uptake by e.g., the coastal redwood in the fog belt region of coastal California provided the stomata are sufficiently open. The omission of the reduction in the water vapor pressure causes a bias in the estimates of the stomatal conductance and leaf internal CO 2 concentration based on leaf gas exchange

  3. Modelo matemático para estimativa da área foliar total de bananeira 'Prata-anã' Esteem method of total leaf area of 'Prata anã' banana tree

    Directory of Open Access Journals (Sweden)

    Moises Zucoloto

    2008-12-01

    Full Text Available O objetivo deste trabalho foi desenvolver um modelo para estimar a área foliar total de bananeira, cultivar Prata-Anã, utilizando dimensões lineares da terceira folha, como o comprimento, a largura e o número total de folhas na emissão da inflorescência. As regressões lineares foram determinadas considerando-se a área foliar total de cada planta (AFT como variável dependente e o comprimento (C e a largura (L da terceira folha, o produto de CxL, o número total de folhas por planta (N e o produto de CxLxN como variáveis independentes. O modelo linear que melhor estimou a área foliar total (AFTe da bananeira 'Prata-Anã', ao nível de 5% de significância com R² de 0,89, foi a equação AFTe = 0,5187(CxLxN + 9603,5.The objective of this work was to estimate the total leaf area of banana, cultivar Prata Anã, according to the linear dimensions of the third leaf, such as the length and the width and the total number of leves in the inflorescence emission. The linear regressions were determined considering total leaf area of each plant (AFT such as dependent variable and the length (C and the width (L of the third leaf, the product of CxL, the total number of leaf per plant (N and the product of CxLxN as independent variables. The best linear model that estimated the total leaf area (AFTe of banana 'Prata Anã' at the level of 5% of significance with R² of 0,89 was the equation AFTe = 0.5187 (CxLxN + 9603.5.

  4. The grapevine root-specific aquaporin VvPIP2;4N controls root hydraulic conductance and leaf gas exchange under well-watered conditions but not under water stress.

    Science.gov (United States)

    Perrone, Irene; Gambino, Giorgio; Chitarra, Walter; Vitali, Marco; Pagliarani, Chiara; Riccomagno, Nadia; Balestrini, Raffaella; Kaldenhoff, Ralf; Uehlein, Norbert; Gribaudo, Ivana; Schubert, Andrea; Lovisolo, Claudio

    2012-10-01

    We functionally characterized the grape (Vitis vinifera) VvPIP2;4N (for Plasma membrane Intrinsic Protein) aquaporin gene. Expression of VvPIP2;4N in Xenopus laevis oocytes increased their swelling rate 54-fold. Northern blot and quantitative reverse transcription-polymerase chain reaction analyses showed that VvPIP2;4N is the most expressed PIP2 gene in root. In situ hybridization confirmed root localization in the cortical parenchyma and close to the endodermis. We then constitutively overexpressed VvPIP2;4N in grape 'Brachetto', and in the resulting transgenic plants we analyzed (1) the expression of endogenous and transgenic VvPIP2;4N and of four other aquaporins, (2) whole-plant, root, and leaf ecophysiological parameters, and (3) leaf abscisic acid content. Expression of transgenic VvPIP2;4N inhibited neither the expression of the endogenous gene nor that of other PIP aquaporins in both root and leaf. Under well-watered conditions, transgenic plants showed higher stomatal conductance, gas exchange, and shoot growth. The expression level of VvPIP2;4N (endogenous + transgene) was inversely correlated to root hydraulic resistance. The leaf component of total plant hydraulic resistance was low and unaffected by overexpression of VvPIP2;4N. Upon water stress, the overexpression of VvPIP2;4N induced a surge in leaf abscisic acid content and a decrease in stomatal conductance and leaf gas exchange. Our results show that aquaporin-mediated modifications of root hydraulics play a substantial role in the regulation of water flow in well-watered grapevine plants, while they have a minor role upon drought, probably because other signals, such as abscisic acid, take over the control of water flow.

  5. Water stress-induced modifications of leaf hydraulic architecture in sunflower: co-ordination with gas exchange.

    Science.gov (United States)

    Nardini, Andrea; Salleo, Sebastiano

    2005-12-01

    The hydraulic architecture, water relationships, and gas exchange of leaves of sunflower plants, grown under different levels of water stress, were measured. Plants were either irrigated with tap water (controls) or with PEG600 solutions with osmotic potential of -0.4 and -0.8 MPa (PEG04 and PEG08 plants, respectively). Mature leaves were measured for hydraulic resistance (R(leaf)) before and after making several cuts across minor veins, thus getting the hydraulic resistance of the venation system (R(venation)). R(leaf) was nearly the same in controls and PEG04 plants but it was reduced by about 30% in PEG08 plants. On the contrary, R(venation) was lowest in controls and increased in PEG04 and PEG08 plants as a likely result of reduction in the diameter of the veins' conduits. As a consequence, the contribution of R(venation) to the overall R(leaf) markedly increased from controls to PEG08 plants. Leaf conductance to water vapour (g(L)) was highest in controls and significantly lower in PEG04 and PEG08 plants. Moreover, g(L) was correlated to R(venation) and to leaf water potential (psi(leaf)) with highly significant linear relationships. It is concluded that water stress has an important effect on the hydraulic construction of leaves. This, in turn, might prove to be a crucial factor in plant-water relationships and gas exchange under water stress conditions.

  6. Current progress and challenges in engineering viable artificial leaf for solar water splitting

    Directory of Open Access Journals (Sweden)

    Phuc D. Nguyen

    2017-12-01

    Full Text Available Large scale production of H2, a clean fuel, can be realized with just water and solar light energy by employing a viable energy conversion device called artificial leaf. In this tutorial review, we discuss on advances achieved recently and technical challenges remained toward the creation of such a leaf. Development of key components like catalysts for water electrolysis process and light harvester for harvesting solar energy as well as strategies being developed for assembling these components to create a complete artificial leaf will be highlighted.

  7. Homeostasis in leaf water potentials on leeward and windward sides of desert shrub crowns: water loss control vs. high hydraulic efficiency.

    Science.gov (United States)

    Iogna, Patricia A; Bucci, Sandra J; Scholz, Fabián G; Goldstein, Guillermo

    2013-11-01

    Phenotypic plasticity in morphophysiological leaf traits in response to wind was studied in two dominant shrub species of the Patagonian steppe, used as model systems for understanding effects of high wind speed on leaf water relations and hydraulic properties of small woody plants. Morpho-anatomical traits, hydraulic conductance and conductivity and water relations in leaves of wind-exposed and protected crown sides were examined during the summer with nearly continuous high winds. Although exposed sides of the crowns were subjected to higher wind speeds and air saturation deficits than the protected sides, leaves throughout the crown had similar minimum leaf water potential (ΨL). The two species were able to maintain homeostasis in minimum ΨL using different physiological mechanisms. Berberis microphylla avoided a decrease in the minimum ΨL in the exposed side of the crown by reducing water loss by stomatal control, loss of cell turgor and low epidermal conductance. Colliguaja integerrima increased leaf water transport efficiency to maintain transpiration rates without increasing the driving force for water loss in the wind-exposed crown side. Leaf physiological changes within the crown help to prevent the decrease of minimum ΨL and thus contribute to the maintenance of homeostasis, assuring the hydraulic integrity of the plant under unfavorable conditions. The responses of leaf traits that contribute to mechanical resistance (leaf mass per area and thickness) differed from those of large physiological traits by exhibiting low phenotypic plasticity. The results of this study help us to understand the unique properties of shrubs which have different hydraulic architecture compared to trees.

  8. Importance of water source in controlling leaf leaching losses in a dwarf red mangrove ( Rhizophora mangle L.) wetland

    Science.gov (United States)

    Davis, Stephen E., III; Childers, Daniel L.

    2007-01-01

    The southern Everglades mangrove ecotone is characterized by extensive dwarf Rhizophora mangle L. shrub forests with a seasonally variable water source (Everglades - NE Florida Bay) and residence times ranging from short to long. We conducted a leaf leaching experiment to understand the influence that water source and its corresponding water quality have on (1) the early decay of R. mangle leaves and (2) the early exchange of total organic carbon (TOC) and total phosphorus (TP) between leaves and the water column. Newly senesced leaves collected from lower Taylor River (FL) were incubated in bottles containing water from one of three sources (Everglades, ambient mangrove, and Florida Bay) that spanned a range of salinity from 0 to 32‰, [TOC] from 710 to 1400 μM, and [TP] from 0.17 to 0.33 μM. We poisoned half the bottles in order to quantify abiotic processes (i.e., leaching) and assumed that non-poisoned bottles represented both biotic (i.e., microbial) and abiotic processes. We sacrificed bottles after 1,2, 5, 10, and 21 days of incubation and quantified changes in leaf mass and changes in water column [TOC] and [TP]. We saw 10-20% loss of leaf mass after 24 h—independent of water treatment—that leveled off by Day 21. After 3 weeks, non-poisoned leaves lost more mass than poisoned leaves, and there was only an effect of salinity on mass loss in poisoned incubations—with greatest leaching-associated losses in Everglades freshwater. Normalized concentrations of TOC in the water column increased by more than two orders of magnitude after 21 days with no effect of salinity and no difference between poisoned and non-poisoned treatments. However, normalized [TP] was lower in non-poisoned incubations as a result of immobilization by epiphytic microbes. This immobilization was greatest in Everglades freshwater and reflects the high P demand in this ecosystem. Immobilization of leached P in mangrove water and Florida Bay water was delayed by several days and may

  9. Molluscicidal activity of crude water leaf extracts of Alternanthera ...

    African Journals Online (AJOL)

    mortality figures by the use of probit gave LC50 of 40.42 (35.15 – 46.47) for the unevaporated crude water while the evaporated crude water extract had LC50 of 48.07 (42.81 – 54.28) for the dried leaf extract. For the fresh leaves the unevaporated crude water extract had LC50 of 32.57 (27.15 – 39.08) and evaporated crude ...

  10. Response of vegetation indices to changes in three measures of leaf water stress

    Science.gov (United States)

    Cohen, Warren B.

    1991-01-01

    The responses of vegetation indices to changes in water stress were evaluated in two separate laboratory experiments. In one experiment the normalized difference vegetation index (NDVI), the near-IR to red ratio (near-IR/red), the Infrared Index (II), and the Moisture Stress Index (MSI) were more highly correlated to leaf water potential in lodgepole pine branches than were the Leaf Water Content Index (LWCI), the mid-IR ratio (Mid-IR), or any of the single Thematic Mapper (TM) bands. In the other experiment, these six indices and the TM Tasseled Cap brightness, greenness, and wetness indices responded to changes in leaf relative water content (RWC) differently than they responded to changes in leaf water content (WC) of three plant species, and the responses were dependent on how experimental replicates were pooled. With no pooling, the LWCI was the most highly correlated index to both RWC and WC among replications, followed by the II, MSI, and wetness. Only the LWCI was highly correlated to RWC and WC when replications were pooled within species. With among species pooling the LWCI was the only index highly correlated with RWC, while the II, MSI, Mid-IR, and wetness were most highly correlated with WC.

  11. Measurements methods and variability assesment of the Norway spruce total leaf area. Implications for remote sensing

    Czech Academy of Sciences Publication Activity Database

    Homolová, L.; Lukeš, Petr; Malenovský, Z.; Lhotáková, Z.; Kaplan, Věroslav; Hanuš, Jan

    2013-01-01

    Roč. 27, č. 1 (2013), s. 111-121 ISSN 0931-1890 R&D Projects: GA ČR GA205/09/ 1989 Institutional support: RVO:67179843 Keywords : chlorophyll content * conversion factor * Picea abies * projected leaf area * remote sensing * total leaf area Subject RIV: EH - Ecology, Behaviour Impact factor: 1.869, year: 2013

  12. Leaf water potential, gas exchange and chlorophyll a fluorescence in acariquara seedlings (Minquartia guianensis Aubl.) under water stress and recovery

    OpenAIRE

    Liberato, Maria Astrid Rocha; Gonçalves, José Francisco de Carvalho; Chevreuil, Larissa Ramos; Nina Junior, Adamir da Rocha; Fernandes, Andreia Varmes; Santos Junior, Ulysses Moreira dos

    2006-01-01

    The physiological performance of acariquara (Minquartia guianensis) seedlings submitted to water deficit and the recovery of physiological parameters during rehydration were investigated in a greenhouse experiment. The analyzed parameters were: leaf water potential, gas exchange and chlorophyll a fluorescence. After thirty-five days, non-irrigated plants exhibited a leaf water potential 70 % lower compared to control plants (irrigated daily) and the stomatal conductance reached values close t...

  13. The enigma of effective pathlength for 18O enrichment in leaf water of conifers

    Science.gov (United States)

    Roden, J. S.; Kahmen, A.; Buchmann, N. C.; Siegwolf, R. T.

    2013-12-01

    The stable isotopes of oxygen (δ18O) in tree ring cellulose provide valuable proxy information about past environments and climate. Mechanistic models have been used to clarify the important drivers of isotope fractionation and help interpret δ18O variation in tree rings. A critical component to these models is an estimate of leaf water enrichment. However, standard models seldom accurately predict 18O enrichment in conifer needles and Péclet corrections often require effective pathlengths (L) that seem unreasonable from the perspective of needle morphology (>0.5 m). To analyze the potential role of path length on the Péclet effect in conifers we carried out experiments in controlled environment chambers. We exposed seedlings of six species of conifer (Abies alba, Larix decidua, Picea abies, Pinus cembra, P. sylvestris, Taxus bacata), that differ in needle morphology, to four different vapor pressure deficits (VPD), in order to modify transpiration rates (E) and leaf water 18O enrichment. Environmental and δ18O data (leaf, stem and chamber water vapor) were collected to parameterize leaf water models. Cross-sections of needles were sampled for an analysis of needle anatomy. Conifer needles have a single strand of vascular tissue making pathlength determinations through anatomical assessments possible. The six species differed in mesophyll distance (measured from endodermis to epidermis) and cell number, with Pinus and Picea species having the shortest distance and Abies and Taxus the longest (flat needle morphology). Other anatomical measures (transfusion distance, cell size etc.) did not differ significantly. A suberized strip was apparent in the endodermis of all species except Taxus and Abies. Conifer needles have a large proportion (from 0.2 to 0.4) of needle cross-sectional area in vascular tissues that may not be subject to evaporative enrichment. As expected, leaf water δ18O and E responded strongly to VPD and standard models (Craig

  14. Herbivory mitigation through increased water-use efficiency in a leaf-mining moth-apple tree relationship.

    Science.gov (United States)

    Pincebourde, Sylvain; Frak, Ela; Sinoquet, Hervé; Regnard, Jean Luc; Casas, Jérôme

    2006-12-01

    Herbivory alters plant gas exchange but the effects depend on the type of leaf damage. In contrast to ectophagous insects, leaf miners, by living inside the leaf tissues, do not affect the integrity of the leaf surface. Thus, the effect of leaf miners on CO2 uptake and water-use efficiency by leaves remains unclear. We explored the impacts of the leaf-mining moth Phyllonorycter blancardella (Lepidoptera: Gracillariidae) on light responses of the apple leaf gas exchanges to determine the balance between the negative effects of reduced photosynthesis and potential positive impacts of increased water-use efficiency (WUE). Gas exchange in intact and mined leaf tissues was measured using an infrared gas analyser. The maximal assimilation rate was slightly reduced but the light response of net photosynthesis was not affected in mined leaf tissues. The transpiration rate was far more affected than the assimilation rate in the mine integument as a result of stomatal closure from moderate to high irradiance level. The WUE was about 200% higher in the mined leaf tissues than in intact leaf portions. Our results illustrate a novel mechanism by which plants might minimize losses from herbivore attacks; via trade-offs between the negative impacts on photosynthesis and the positive effects of increased WUE.

  15. Leaf water 18 O and 2 H enrichment along vertical canopy profiles in a broadleaved and a conifer forest tree.

    Science.gov (United States)

    Bögelein, Rebekka; Thomas, Frank M; Kahmen, Ansgar

    2017-07-01

    Distinguishing meteorological and plant-mediated drivers of leaf water isotopic enrichment is prerequisite for ecological interpretations of stable hydrogen and oxygen isotopes in plant tissue. We measured input and leaf water δ 2 H and δ 18 O as well as micrometeorological and leaf morpho-physiological variables along a vertical gradient in a mature angiosperm (European beech) and gymnosperm (Douglas fir) tree. We used these variables and different enrichment models to quantify the influence of Péclet and non-steady state effects and of the biophysical drivers on leaf water enrichment. The two-pool model accurately described the diurnal variation of leaf water enrichment. The estimated unenriched water fraction was linked to leaf dry matter content across the canopy heights. Non-steady state effects and reduced stomatal conductance caused a higher enrichment of Douglas fir compared to beech leaf water. A dynamic effect analyses revealed that the light-induced vertical gradients of stomatal conductance and leaf temperature outbalanced each other in their effects on evaporative enrichment. We conclude that neither vertical canopy gradients nor the Péclet effect is important for estimates and interpretation of isotopic leaf water enrichment in hypostomatous trees. Contrarily, species-specific non-steady state effects and leaf temperatures as well as the water vapour isotope composition need careful consideration. © 2017 John Wiley & Sons Ltd.

  16. Water use in forest canopy black cherry trees and its relationship to leaf gas exchange and environment

    Science.gov (United States)

    B. J. Joyce; K. C. Steiner; J. M. Skelly

    1996-01-01

    Models of canopy gas exchange are needed to connect leaf-level measurement to higher scales. Because of the correspondence between leaf gas exchange and water use, it may be possible to predict variation in leaf gas exchange at the canopy level by monitoring rates of branch water use.

  17. An extended PROSPECT: Advance in the leaf optical properties model separating total chlorophylls into chlorophyll a and b.

    Science.gov (United States)

    Zhang, Yao; Huang, Jingfeng; Wang, Fumin; Blackburn, George Alan; Zhang, Hankui K; Wang, Xiuzhen; Wei, Chuanwen; Zhang, Kangyu; Wei, Chen

    2017-07-25

    The PROSPECT leaf optical model has, to date, well-separated the effects of total chlorophyll and carotenoids on leaf reflectance and transmittance in the 400-800 nm. Considering variations in chlorophyll a:b ratio with leaf age and physiological stress, a further separation of total plant-based chlorophylls into chlorophyll a and chlorophyll b is necessary for advanced monitoring of plant growth. In this study, we present an extended version of PROSPECT model (hereafter referred to as PROSPECT-MP) that can combine the effects of chlorophyll a, chlorophyll b and carotenoids on leaf directional hemispherical reflectance and transmittance (DHR and DHT) in the 400-800 nm. The LOPEX93 dataset was used to evaluate the capabilities of PROSPECT-MP for spectra modelling and pigment retrieval. The results show that PROSPECT-MP can both simultaneously retrieve leaf chlorophyll a and b, and also performs better than PROSPECT-5 in retrieving carotenoids concentrations. As for the simulation of DHR and DHT, the performances of PROSPECT-MP are similar to that of PROSPECT-5. This study demonstrates the potential of PROSPECT-MP for improving capabilities of remote sensing of leaf photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids) and for providing a framework for future refinements in the modelling of leaf optical properties.

  18. Effect of water availability on tolerance of leaf damage in tall morning glory, Ipomoea purpurea

    Science.gov (United States)

    Atala, Cristian; Gianoli, Ernesto

    2009-03-01

    Resource availability may limit plant tolerance of herbivory. To predict the effect of differential resource availability on plant tolerance, the limiting resource model (LRM) considers which resource limits plant fitness and which resource is mostly affected by herbivore damage. We tested the effect of experimental drought on tolerance of leaf damage in Ipomoea purpurea, which is naturally exposed to both leaf damage and summer drought. To seek mechanistic explanations, we also measured several morphological, allocation and gas exchange traits. In this case, LRM predicts that tolerance would be the same in both water treatments. Plants were assigned to a combination of two water treatments (control and low water) and two damage treatments (50% defoliation and undamaged). Plants showed tolerance of leaf damage, i.e., a similar number of fruits were produced by damaged and undamaged plants, only in control water. Whereas experimental drought affected all plant traits, leaf damage caused plants to show a greater leaf trichome density and reduced shoot biomass, but only in low water. It is suggested that the reduced fitness (number of fruits) of damaged plants in low water was mediated by the differential reduction of shoot biomass, because the number of fruits per shoot biomass was similar in damaged and undamaged plants. Alternative but less likely explanations include the opposing direction of functional responses to drought and defoliation, and resource costs of the damage-induced leaf trichome density. Our results somewhat challenge the LRM predictions, but further research including field experiments is needed to validate some of the preliminary conclusions drawn.

  19. Towards Estimating Water Stress through Leaf and Canopy Water Content Derived from Optical and Thermal Hyperspectral Data

    Science.gov (United States)

    Corbin, Amie; Timmermans, Joris; van der Tol, Christiaan; Verhoef, Wout

    2015-04-01

    A competition for available (drinkable) water has arisen. This competition originated due to increasing global population and the respective needs of this population. The water demand for human consumption and irrigation of food producing crops and biofuel related vegetation, has led to early indication of drought as a key issue in many studies. However, while drought monitoring systems might provide some reasonable predictions, at the time of visible symptoms of plant stress, a plant may already be critically affected. Consequently, pre-symptomatic non-destructive monitoring of plants is needed. In many studies of plant stress, this is performed by examining internal plant physiology through existing remote sensing techniques, with varying applications. However, a uniform remote sensing method for identifying early plant stress under drought conditions is still developing. In some instances, observations of vegetation water content are used to assess the impact of soil water deficit on the health of a plant or canopy. When considering water content as an indicator of water stress in a plant, this comments not only on the condition of the plant itself, but also provides indicators of photosynthetic activity and the susceptibility to drought. Several indices of canopy health currently exists (NDVI, DVI, SAVI, etc.) using optical and near infrared reflectance bands. However, these are considered inadequate for vegetation health investigations because such semi-empirical models result in less accuracy for canopy measurements. In response, a large amount of research has been conducted to estimate canopy health directly from considering the full spectral behaviour. In these studies , the canopy reflectance has been coupled to leaf parameters, by using coupling leaf radiative transfer models (RTM), such as PROSPECT, to a canopy RTM such as SAIL. The major shortcomings of these researches is that they have been conducted primarily for optical remote sensing. Recently

  20. A 3-D functional-structural grapevine model that couples the dynamics of water transport with leaf gas exchange.

    Science.gov (United States)

    Zhu, Junqi; Dai, Zhanwu; Vivin, Philippe; Gambetta, Gregory A; Henke, Michael; Peccoux, Anthony; Ollat, Nathalie; Delrot, Serge

    2017-12-23

    Predicting both plant water status and leaf gas exchange under various environmental conditions is essential for anticipating the effects of climate change on plant growth and productivity. This study developed a functional-structural grapevine model which combines a mechanistic understanding of stomatal function and photosynthesis at the leaf level (i.e. extended Farqhuhar-von Caemmerer-Berry model) and the dynamics of water transport from soil to individual leaves (i.e. Tardieu-Davies model). The model included novel features that account for the effects of xylem embolism (fPLC) on leaf hydraulic conductance and residual stomatal conductance (g0), variable root and leaf hydraulic conductance, and the microclimate of individual organs. The model was calibrated with detailed datasets of leaf photosynthesis, leaf water potential, xylem sap abscisic acid (ABA) concentration and hourly whole-plant transpiration observed within a soil drying period, and validated with independent datasets of whole-plant transpiration under both well-watered and water-stressed conditions. The model well captured the effects of radiation, temperature, CO2 and vapour pressure deficit on leaf photosynthesis, transpiration, stomatal conductance and leaf water potential, and correctly reproduced the diurnal pattern and decline of water flux within the soil drying period. In silico analyses revealed that decreases in g0 with increasing fPLC were essential to avoid unrealistic drops in leaf water potential under severe water stress. Additionally, by varying the hydraulic conductance along the pathway (e.g. root and leaves) and changing the sensitivity of stomatal conductance to ABA and leaf water potential, the model can produce different water use behaviours (i.e. iso- and anisohydric). The robust performance of this model allows for modelling climate effects from individual plants to fields, and for modelling plants with complex, non-homogenous canopies. In addition, the model provides a

  1. DIURNAL CHANGES IN LEAF PHOTOSYNTHESIS AND RELATIVE WATER CONTENT OF GRAPEVINE

    Directory of Open Access Journals (Sweden)

    Monica Popescu

    2014-11-01

    Full Text Available Variation in light intensity, air temperature and relative air humidity leads to diurnal variations of photosynthetic rate and leaf relative water content. In order to determine the diurnal changes in net photosynthetic rate of vine plants and influence of the main environmental factors, gas exchange in the vine leaves were measure using a portable plant CO2 analysis package. The results show that diurnal changes in photosynthetic rate could be interpreted as single-peak curve, with a maximum at noon (10.794 μmol CO2 m-2 s-1. Leaf relative water content has maximum value in the morning; the values may slightly decrease during the day (day of June, with normal temperature, no rain, no water restriction in soil.

  2. In vitro antioxidant evaluation and total phenolics of methanolic leaf extracts of Nyctanthes arbor-tristis L.

    Science.gov (United States)

    Michael, J Savarimuthu; Kalirajan, A; Padmalatha, C; Singh, A J A Ranjit

    2013-09-01

    To investigate the in vitro antioxidant activity and total phenolic content of the methanolic leaf extract of Nyctanthes arbor-tristis L. (NA). The sample was tested using five in vitro antioxidant methods (1, 1-diphenyl-2-picryl hydrazine radical scavenging activity (DPPH), hydroxyl radical-scavenging activity (-OH), nitric oxide scavenging activity (NO), superoxide radical-scavenging activity, and total antioxidant activity) to evaluate the in vitro antioxidant potential of NA and the total phenolic content (Folin-Ciocalteu method). The extract showed good free radical scavenging property which was calculated as an IC50 value. IC50 (Half maximal inhibitory concentration) of the methanolic extract was found to be 57.93 μg·mL(-1) for DPPH, 98.61 μg·mL(-1) for -OH, 91.74 μg·mL(-1) for NO, and 196.07 μg·mL(-1) for superoxide radical scavenging activity. Total antioxidant capacity of the extract was found to be (1198 ± 24.05) mg ascorbic acid for the methanolic extract. Free radical scavenging activity observed in the extracts of NA showed a concentration-dependent reaction. The in vitro scavenging tested for free radicals was reported to be due to high phenolic content in the leaf extract. The leaf extract of NA showed the highest total phenolic content with a value of 78.48 ± 4.2 equivalent mg TAE/g (tannic acid equivalent). N. arbor-tristis leaf extract exhibited potent free radical scavenging activity. The finding suggests that N. arbor-tristis leaves could be a potential source of natural antioxidant. Copyright © 2013 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

  3. "Breath figures" on leaf surfaces-formation and effects of microscopic leaf wetness.

    Science.gov (United States)

    Burkhardt, Juergen; Hunsche, Mauricio

    2013-01-01

    "Microscopic leaf wetness" means minute amounts of persistent liquid water on leaf surfaces which are invisible to the naked eye. The water is mainly maintained by transpired water vapor condensing onto the leaf surface and to attached leaf surface particles. With an estimated average thickness of less than 1 μm, microscopic leaf wetness is about two orders of magnitude thinner than morning dewfall. The most important physical processes which reduce the saturation vapor pressure and promote condensation are cuticular absorption and the deliquescence of hygroscopic leaf surface particles. Deliquescent salts form highly concentrated solutions. Depending on the type and concentration of the dissolved ions, the physicochemical properties of microscopic leaf wetness can be considerably different from those of pure water. Microscopic leaf wetness can form continuous thin layers on hydrophobic leaf surfaces and in specific cases can act similar to surfactants, enabling a strong potential influence on the foliar exchange of ions. Microscopic leaf wetness can also enhance the dissolution, the emission, and the reaction of specific atmospheric trace gases e.g., ammonia, SO2, or ozone, leading to a strong potential role for microscopic leaf wetness in plant/atmosphere interaction. Due to its difficult detection, there is little knowledge about the occurrence and the properties of microscopic leaf wetness. However, based on the existing evidence and on physicochemical reasoning it can be hypothesized that microscopic leaf wetness occurs on almost any plant worldwide and often permanently, and that it significantly influences the exchange processes of the leaf surface with its neighboring compartments, i.e., the plant interior and the atmosphere. The omission of microscopic water in general leaf wetness concepts has caused far-reaching, misleading conclusions in the past.

  4. Difference in leaf water use efficiency/photosynthetic nitrogen use efficiency of Bt-cotton and its conventional peer.

    Science.gov (United States)

    Guo, Ruqing; Sun, Shucun; Liu, Biao

    2016-09-15

    This study is to test the effects of Bt gene introduction on the foliar water/nitrogen use efficiency in cotton. We measured leaf stomatal conductance, photosynthetic rate, and transpiration rate under light saturation condition at different stages of a conventional cultivar (zhongmian no. 16) and its counterpart Bt cultivar (zhongmian no. 30) that were cultured on three levels of fertilization, based on which leaf instantaneous water use efficiency was derived. Leaf nitrogen concentration was measured to calculate leaf photosynthetic nitrogen use efficiency, and leaf δ(13)C was used to characterize long term water use efficiency. Bt cultivar was found to have lower stomatal conductance, net photosynthetic rates and transpiration rates, but higher instantaneous and long time water use efficiency. In addition, foliar nitrogen concentration was found to be higher but net photosynthetic rate was lower in the mature leaves of Bt cultivar, which led to lower photosynthetic nitrogen use efficiency. This might result from the significant decrease of photosynthetic rate due to the decrease of stomatal conductance. In conclusion, our findings show that the introduction of Bt gene should significantly increase foliar water use efficiency but decrease leaf nitrogen use efficiency in cotton under no selective pressure.

  5. Effects of water stress on irradiance acclimation of leaf traits in almond trees.

    Science.gov (United States)

    Egea, Gregorio; González-Real, María M; Baille, Alain; Nortes, Pedro A; Conesa, María R; Ruiz-Salleres, Isabel

    2012-04-01

    Photosynthetic acclimation to highly variable local irradiance within the tree crown plays a primary role in determining tree carbon uptake. This study explores the plasticity of leaf structural and physiological traits in response to the interactive effects of ontogeny, water stress and irradiance in adult almond trees that have been subjected to three water regimes (full irrigation, deficit irrigation and rain-fed) for a 3-year period (2006-08) in a semiarid climate. Leaf structural (dry mass per unit area, N and chlorophyll content) and photosynthetic (maximum net CO(2) assimilation, A(max), maximum stomatal conductance, g(s,max), and mesophyll conductance, g(m)) traits and stem-to-leaf hydraulic conductance (K(s-l)) were determined throughout the 2008 growing season in leaves of outer south-facing (S-leaves) and inner northwest-facing (NW-leaves) shoots. Leaf plasticity was quantified by means of an exposure adjustment coefficient (ε=1-X(NW)/X(S)) for each trait (X) of S- and NW-leaves. Photosynthetic traits and K(s-l) exhibited higher irradiance-elicited plasticity (higher ε) than structural traits in all treatments, with the highest and lowest plasticity being observed in the fully irrigated and rain-fed trees, respectively. Our results suggest that water stress modulates the irradiance-elicited plasticity of almond leaves through changes in crown architecture. Such changes lead to a more even distribution of within-crown irradiance, and hence of the photosynthetic capacity, as water stress intensifies. Ontogeny drove seasonal changes only in the ε of area- and mass-based N content and mass-based chlorophyll content, while no leaf age-dependent effect was observed on ε as regards the physiological traits. Our results also indicate that the irradiance-elicited plasticity of A(max) is mainly driven by changes in leaf dry mass per unit area, in g(m) and, most likely, in the partitioning of the leaf N content.

  6. On the Controls of Leaf-Water Oxygen Isotope Ratios in the Atmospheric Crassulacean Acid Metabolism Epiphyte Tillandsia usneoides1[W][OA

    Science.gov (United States)

    Helliker, Brent R.

    2011-01-01

    Previous theoretical work showed that leaf-water isotope ratio (δ18OL) of Crassulacean acid metabolism epiphytes was controlled by the δ18O of atmospheric water vapor (δ18Oa), and observed δ18OL could be explained by both a non-steady-state model and a “maximum enrichment” steady-state model (δ18OL-M), the latter requiring only δ18Oa and relative humidity (h) as inputs. δ18OL, therefore, should contain an extractable record of δ18Oa. Previous empirical work supported this hypothesis but raised many questions. How does changing δ18Oa and h affect δ18OL? Do hygroscopic trichomes affect observed δ18OL? Are observations of changes in water content required for the prediction of δ18OL? Does the leaf need to be at full isotopic steady state for observed δ18OL to equal δ18OL-M? These questions were examined with a climate-controlled experimental system capable of holding δ18Oa constant for several weeks. Water adsorbed to trichomes required a correction ranging from 0.5‰ to 1‰. δ18OL could be predicted using constant values of water content and even total conductance. Tissue rehydration caused a transitory change in δ18OL, but the consequent increase in total conductance led to a tighter coupling with δ18Oa. The non-steady-state leaf water models explained observed δ18OL (y = 0.93*x − 0.07; r2 = 0.98) over a wide range of δ18Oa and h. Predictions of δ18OL-M agreed with observations of δ18OL (y = 0.87*x − 0.99; r2 = 0.92), and when h > 0.9, the leaf did not need to be at isotopic steady state for the δ18OL-M model to predict δ18OL in the Crassulacean acid metabolism epiphyte Tillandsia usneoides. PMID:21300917

  7. Interacting Effects of Leaf Water Potential and Biomass on Vegetation Optical Depth: Effects of LWP and Biomass on VOD

    Energy Technology Data Exchange (ETDEWEB)

    Momen, Mostafa [Department of Earth System Science, Stanford University, Stanford CA USA; Wood, Jeffrey D. [School of Natural Resources, University of Missouri, Columbia MO USA; Novick, Kimberly A. [School of Public and Environmental Affairs, Indiana University-Bloomington, Bloomington IN USA; Pangle, Robert [Department of Biology, University of New Mexico, Albuquerque NM USA; Pockman, William T. [Department of Biology, University of New Mexico, Albuquerque NM USA; McDowell, Nate G. [Pacific Northwest National Laboratory, Richland WA USA; Konings, Alexandra G. [Department of Earth System Science, Stanford University, Stanford CA USA

    2017-11-01

    Remotely sensed microwave observations of vegetation optical depth (VOD) have been widely used for examining vegetation responses to climate. Nevertheless, the relative impacts of phenological changes in leaf biomass and water stress on VOD have not been explicitly disentangled. In particular, determining whether leaf water potential (ψL) affects VOD may allow these data sets as a constraint for plant hydraulic models. Here we test the sensitivity of VOD to variations in ψL and present a conceptual framework that relates VOD to ψL and total biomass including leaves, whose dynamics are measured through leaf area index, and woody components. We used measurements of ψL from three sites across the US—a mixed deciduous forests in Indiana and Missouri and a piñon-juniper woodland in New Mexico—to validate the conceptual model. The temporal dynamics of X-band VOD were similar to those of the VOD signal estimated from the new conceptual model with observed ψL (R2 = 0.6–0.8). At the global scale, accounting for a combination of biomass and estimated ψL (based on satellite surface soil moisture data) increased correlations with VOD by ~ 15% and 30% compared to biomass and water potential, respectively. In wetter regions with denser and taller canopy heights, VOD has a higher correlation with leaf area index than with water stress and vice versa in drier regions. Our results demonstrate that variations in both phenology and ψL must be considered to accurately interpret the dynamics of VOD observations for ecological applications.

  8. Leaf and shoot water content and leaf dry matter content of Mediterranean woody species with different post-fire regenerative strategies.

    Science.gov (United States)

    Saura-Mas, S; Lloret, F

    2007-03-01

    Post-fire regeneration is a key process in Mediterranean shrubland dynamics, strongly determining the functional properties of the community. In this study, a test is carried out to determine whether there is co-variation between species regenerative types and functional attributes related to water use. An analysis was made of the seasonal variations in leaf relative water content (RWC), leaf dry matter content (LDMC), leaf moisture (LM) and live fine fuel moisture (LFFM) in 30 woody species of a coastal shrubland, with different post-fire regenerative strategies (seeding, resprouting or both). RWC results suggest that the studied resprouters have more efficient mechanisms to reduce water losses and maintain water supply between seasons. In contrast, seeders are more drought tolerant. LDMC is higher in resprouters over the course of the year, suggesting a more efficient conservation of nutrients. The weight of the phylogenetic constraint to understand differences between regenerative strategies tends to be important for LDMC, while it is not the case for variables such as RWC. Groups of species with different post-fire regenerative strategies (seeders and resprouters) have different functional traits related to water use. In addition to the role of phylogenetical constraints, these differences are also likely to be related to the respective life history characteristics. Therefore, the presence and abundance of species with different post-fire regenerative responses influence the functional properties of the communities.

  9. Characterization of a plant leaf cuticle model wax, phase behaviour of model wax–water systems

    International Nuclear Information System (INIS)

    Fagerström, Anton; Kocherbitov, Vitaly; Westbye, Peter; Bergström, Karin; Mamontova, Varvara; Engblom, Johan

    2013-01-01

    Highlights: • Four individual crystalline phases were discovered in the model wax–water system. • Eutectic melting occurred in both dry and hydrated model wax. • The total transition enthalpy is smaller for the cuticle wax than for the model wax. • Water has a large plasticizing effect on cuticle wax. • The thermotropic transitions of model wax fit in the window of extracted leaf waxes. - Abstract: We investigated the thermotropic phase behaviour of plant leaf intracuticular wax and two representatives of its main components, 1-docosanol (C 22 H 45 OH) and dotriacontane (C 32 H 66 ), in dry and hydrated state. One objective was to obtain a model wax, which can be used to estimate formulations effects on cuticle diffusivity in vitro. The two wax components were chosen based on results from Gas Chromatography coupled to Mass Spectrometry analysis of cuticular wax. The wax was extracted from Clivia Miniata Regel leaves and contained 68% primary alcohols (C 16 –C 32 ) and 16% n-alkanes (C 21 –C 33 ). Differential Scanning Calorimetry, Polarized Light Microscopy and Small- and Wide Angle X-ray Diffraction were used to characterize the cuticular extract and the phase behaviour of the C 22 H 45 OH/C 32 H 66 /H 2 O model system. Four individual crystalline phases were discovered in the model wax–water system and eutectic melting occurred in both dry and hydrated state. The thermotropic transitions of the model wax occur within the broader transition region of the extracted leaf wax

  10. Transition of the Isotopic Composition of Leaf Water to the Isotopic Steady State in Soybean and Corn

    Science.gov (United States)

    Kim, K.; Lee, X.; Welp, L. R.

    2007-12-01

    The isotope composition of leaf water (δL) plays an important role in the isotopic water and carbon fluxes between terrestrial plants and the atmosphere. The objective of this study is to improve our understanding of environmental and biological controls on the transition of δL to steady state through laboratory experiments. Plants (soybean, Glycine max; corn, Zea mays) were grown hydroponically with water of a known isotopic content in a greenhouse. On the day of the experiment, they were first moved to ambient environment in full sunlight for at least 6 hr and then into a dark container inside the lab for up to 48 hr in which water vapor isotope ratios, temperature, and humidity were controlled. This arrangement created a step change in the forcing on the plant isotopic exchange. Leaves were sampled prior to the transfer to the dark container and 6 more times every 4 - 12 hr over the experiment. In the first set of experiments, humidity inside the container was saturated to mimic dew events in field conditions. In the second set, humidity was controlled at approximately 95%. Water from the leaf samples was extracted by a vacuum line and was analyzed for both δD and δ18O. The dataset will allow us to evaluate leaf water isotopic theories by exploring the transitions of δL in response to the step change. Specifically, we are interested in whether the stomatal opening is an effective pathway for gaseous exchange in total darkness and how the transitional behaviors of δL differ between the C3 and C4 photosynthesis pathways.

  11. Up-scaling of water use efficiency from leaf to canopy as based on leaf gas exchange relationships and the modeled in-canopy light distribution

    DEFF Research Database (Denmark)

    Linderson, Maj-Lena; Mikkelsen, Teis Nørgaard; Ibrom, Andreas

    2012-01-01

    The aim of this study was to evaluate the extent to which water use efficiency (WUE) at leaf scale can be used to assess WUE at canopy scale, leaf WUE being assumed to be a constant function of vapor pressure deficit and to thus not be dependent upon other environmental factors or varying leaf...... properties. Leaf WUE and its variability and dependencies were assessed using leafgas-exchange measurements obtained during two growing seasons, 1999 and 2000, at the Soroe beech forest study site on Zealand in Denmark. It was found that the VPD-normalized leaf WUE, WUEnormleaf, although dependent...

  12. Spectroscopic determination of leaf water content using linear ...

    African Journals Online (AJOL)

    DR. NJ TONUKARI

    2012-02-02

    Feb 2, 2012 ... characteristics, this study measured 33 groups of peach tree leaf ... spectral absorption values were obtained from a total of 33 groups of leaves .... using the trial and error method, based on the following empirical ... be used as indicators for evaluation of prediction models. .... Comparison of the methods of.

  13. Leaf gas exchange, carbon isotope discrimination, and grain yield in contrasting rice genotypes subjected to water deficits during the reproductive stage.

    Science.gov (United States)

    Centritto, Mauro; Lauteri, Marco; Monteverdi, Maria Cristina; Serraj, Rachid

    2009-01-01

    Genotypic variations in leaf gas exchange and yield were analysed in five upland-adapted and three lowland rice cultivars subjected to a differential soil moisture gradient, varying from well-watered to severely water-stressed conditions. A reduction in the amount of water applied resulted in a significant decrease in leaf gas exchange and, subsequently, in above-ground dry mass and grain yield, that varied among genotypes and distance from the line source. The comparison between the variable J and the Delta values in recently synthesized sugars methods, yielded congruent estimations of mesophyll conductance (g(m)), confirming the reliability of these two techniques. Our data demonstrate that g(m) is a major determinant of photosynthesis (A), because rice genotypes with inherently higher g(m) were capable of keeping higher A in stressed conditions. Furthermore, A, g(s), and g(m) of water-stressed genotypes rapidly recovered to the well-watered values upon the relief of water stress, indicating that drought did not cause any lasting metabolic limitation to photosynthesis. The comparisons between the A/C(i) and corresponding A/C(c) curves, measured in the genotypes that showed intrinsically higher and lower instantaneous A, confirmed this finding. Moreover, the effect of drought stress on grain yield was correlated with the effects on both A and total diffusional limitations to photosynthesis. Overall, these data indicate that genotypes which showed higher photosynthesis and conductances were also generally more productive across the entire soil moisture gradient. The analysis of Delta revealed a substantial variation of water use efficiency among the genotypes, both on the long-term (leaf pellet analysis) and short-term scale (leaf soluble sugars analysis).

  14. Quantification of water uptake by arbuscular mycorrhizal hyphae and its significance for leaf growth, water relations, and gas exchange of barley subjected to drought stress.

    Science.gov (United States)

    Khalvati, M A; Hu, Y; Mozafar, A; Schmidhalter, U

    2005-11-01

    Arbuscular mycorrhizal fungi alleviate drought stress in their host plants via the direct uptake and transfer of water and nutrients through the fungal hyphae to the host plants. To quantify the contribution of the hyphae to plant water uptake, a new split-root hyphae system was designed and employed on barley grown in loamy soil inoculated with Glomus intraradices under well-watered and drought conditions in a growth chamber with a 14-h light period and a constant temperature (15 degrees C; day/night). Drought conditions were initiated 21 days after sowing, with a total of eight 7-day drying cycles applied. Leaf water relations, net photosynthesis rates, and stomatal conductance were measured at the end of each drying cycle. Plants were harvested 90 days after sowing. Compared to the control treatment, the leaf elongation rate and the dry weight of the shoots and roots were reduced in all plants under drought conditions. However, drought resistance was comparatively increased in the mycorrhizal host plants, which suffered smaller decreases in leaf elongation, net photosynthetic rate, stomatal conductance, and turgor pressure compared to the non-mycorrhizal plants. Quantification of the contribution of the arbuscular mycorrhizal hyphae to root water uptake showed that, compared to the non-mycorrhizal treatment, 4 % of water in the hyphal compartment was transferred to the root compartment through the arbuscular mycorrhizal hyphae under drought conditions. This indicates that there is indeed transport of water by the arbuscular mycorrhizal hyphae under drought conditions. Although only a small amount of water transport from the hyphal compartment was detected, the much higher hyphal density found in the root compartment than in the hyphal compartment suggests that a larger amount of water uptake by the arbuscular mycorrhizal hyphae may occur in the root compartment.

  15. Phytochemicals Screening, Total Phenol Estimation, Antioxidant Activity of Blainvillea Acmella Leaf and Stem Successive Extracts

    International Nuclear Information System (INIS)

    Sharma, P.; Sharma, G.N.; Shrivastava, B.; Jadhav, H.R.

    2014-01-01

    The aim of present work was to investigate antioxidant potential of different extracts of Blainvillea acmella leaf and stem. The successive extraction of individual plant part was carried out using solvents of different polarity viz. n-hexane, ethyl acetate, methanol and water. Preliminary phyto chemical screening of all the extracts was done. The present total phenolic contents were estimated by Folin-Ciocalteu reagent method and expressed as μg/ mg of gallic acid equivalent. The antioxidant potential and reducing power of all the prepared extracts were measured against DPPH, as compared to standard ascorbic acid, and BHA respectively. The result data indicate that the phenolic contents were higher in methanolic extracts of leaf (73.67 ± 0.38 mg/ g) followed by ethyl acetate (29.08 ± 0.38 mg/ g), aqueous (21.50 ± 0.28 mg/ g), and n-Hexane (9.29 ± 0.38 mg/ g); gallic acid equivalent. The similar pattern in stem part was also observed for example methanolic extracts (41.90 ± 0.45 mg/ g), ethyl acetate (21.92 ± 0.28 mg/ g), aqueous (15.13 ± 0.18 mg/ g), and n-Hexane (3.69 ± 0.28 mg/ g). The antioxidant capacity of methanolic extract of both the part for example leaf and stem was found to be maximum, as IC50 values were 226.49 ± 0.16, 402.05 ± 1.10 respectively. The reducing power was also highest in methanol extract of both parts. The result data conclude that the higher antioxidant as well as reducing power may be due to present phenolic contents. (author)

  16. Effects of leaf age within growth stages of pepper and sorghum plants on leaf thickness, water, chlorophyll, and light reflectance. [in spectral vegetation discrimination

    Science.gov (United States)

    Gausman, H. W.; Cardenas, R.; Berumen, A.

    1974-01-01

    Pepper and sorghum plants (characterized by porous and compact leaf mesophylls, respectively) were used to study the influence of leaf age on light reflectance. Measurements were limited to the upper five nodal positions within each growth stage, since upper leaves make up most of the reflectance surfaces remotely sensed. The increase in leaf thickness and water content with increasing leaf age was taken into consideration, since each of these factors affects the reflectance as well as the selection of spectral wavelength intervals for optimum discrimination of vegetation.

  17. Drought-Induced Leaf Proteome Changes in Switchgrass Seedlings

    Directory of Open Access Journals (Sweden)

    Zhujia Ye

    2016-08-01

    Full Text Available Switchgrass (Panicum virgatum is a perennial crop producing deep roots and thus highly tolerant to soil water deficit conditions. However, seedling establishment in the field is very susceptible to prolonged and periodic drought stress. In this study, a “sandwich” system simulating a gradual water deletion process was developed. Switchgrass seedlings were subjected to a 20-day gradual drought treatment process when soil water tension was increased to 0.05 MPa (moderate drought stress and leaf physiological properties had expressed significant alteration. Drought-induced changes in leaf proteomes were identified using the isobaric tags for relative and absolute quantitation (iTRAQ labeling method followed by nano-scale liquid chromatography mass spectrometry (nano-LC-MS/MS analysis. Additionally, total leaf proteins were processed using a combinatorial library of peptide ligands to enrich for lower abundance proteins. Both total proteins and those enriched samples were analyzed to increase the coverage of the quantitative proteomics analysis. A total of 7006 leaf proteins were identified, and 257 (4% of the leaf proteome expressed a significant difference (p < 0.05, fold change <0.6 or >1.7 from the non-treated control to drought-treated conditions. These proteins are involved in the regulation of transcription and translation, cell division, cell wall modification, phyto-hormone metabolism and signaling transduction pathways, and metabolic pathways of carbohydrates, amino acids, and fatty acids. A scheme of abscisic acid (ABA-biosynthesis and ABA responsive signal transduction pathway was reconstructed using these drought-induced significant proteins, showing systemic regulation at protein level to deploy the respective mechanism. Results from this study, in addition to revealing molecular responses to drought stress, provide a large number of proteins (candidate genes that can be employed to improve switchgrass seedling growth and

  18. Specific leaf areas of the tank bromeliad Guzmania monostachia perform distinct functions in response to water shortage.

    Science.gov (United States)

    Freschi, Luciano; Takahashi, Cassia Ayumi; Cambui, Camila Aguetoni; Semprebom, Thais Ribeiro; Cruz, Aline Bertinatto; Mioto, Paulo Tamoso; de Melo Versieux, Leonardo; Calvente, Alice; Latansio-Aidar, Sabrina Ribeiro; Aidar, Marcos Pereira Marinho; Mercier, Helenice

    2010-05-01

    Leaves comprise most of the vegetative body of tank bromeliads and are usually subjected to strong longitudinal gradients. For instance, while the leaf base is in contact with the water accumulated in the tank, the more light-exposed middle and upper leaf sections have no direct access to this water reservoir. Therefore, the present study attempted to investigate whether different leaf portions of Guzmania monostachia, a tank-forming C(3)-CAM bromeliad, play distinct physiological roles in response to water shortage, which is a major abiotic constraint in the epiphytic habitat. Internal and external morphological features, relative water content, pigment composition and the degree of CAM expression were evaluated in basal, middle and apical leaf portions in order to allow the establishment of correlations between the structure and the functional importance of each leaf region. Results indicated that besides marked structural differences, a high level of functional specialization is also present along the leaves of this bromeliad. When the tank water was depleted, the abundant hydrenchyma of basal leaf portions was the main reservoir for maintaining a stable water status in the photosynthetic tissues of the apical region. In contrast, the CAM pathway was intensified specifically in the upper leaf section, which is in agreement with the presence of features more suitable for the occurrence of photosynthesis at this portion. Gas exchange data indicated that internal recycling of respiratory CO(2) accounted for virtually all nighttime acid accumulation, characterizing a typical CAM-idling pathway in the drought-exposed plants. Altogether, these data reveal a remarkable physiological complexity along the leaves of G. monostachia, which might be a key adaptation to the intermittent water supply of the epiphytic niche. Copyright 2009 Elsevier GmbH. All rights reserved.

  19. The role of water channel proteins in facilitating recovery of leaf hydraulic conductance from water stress in Populus trichocarpa.

    Directory of Open Access Journals (Sweden)

    Joan Laur

    Full Text Available Gas exchange is constrained by the whole-plant hydraulic conductance (Kplant. Leaves account for an important fraction of Kplant and may therefore represent a major determinant of plant productivity. Leaf hydraulic conductance (Kleaf decreases with increasing water stress, which is due to xylem embolism in leaf veins and/or the properties of the extra-xylary pathway. Water flow through living tissues is facilitated and regulated by water channel proteins called aquaporins (AQPs. Here we assessed changes in the hydraulic conductance of Populus trichocarpa leaves during a dehydration-rewatering episode. While leaves were highly sensitive to drought, Kleaf recovered only 2 hours after plants were rewatered. Recovery of Kleaf was absent when excised leaves were bench-dried and subsequently xylem-perfused with a solution containing AQP inhibitors. We examined the expression patterns of 12 highly expressed AQP genes during a dehydration-rehydration episode to identify isoforms that may be involved in leaf hydraulic adjustments. Among the AQPs tested, several genes encoding tonoplast intrinsic proteins (TIPs showed large increases in expression in rehydrated leaves, suggesting that TIPs contribute to reversing drought-induced reductions in Kleaf. TIPs were localized in xylem parenchyma, consistent with a role in facilitating water exchange between xylem vessels and adjacent living cells. Dye uptake experiments suggested that reversible embolism formation in minor leaf veins contributed to the observed changes in Kleaf.

  20. The role of water channel proteins in facilitating recovery of leaf hydraulic conductance from water stress in Populus trichocarpa.

    Science.gov (United States)

    Laur, Joan; Hacke, Uwe G

    2014-01-01

    Gas exchange is constrained by the whole-plant hydraulic conductance (Kplant). Leaves account for an important fraction of Kplant and may therefore represent a major determinant of plant productivity. Leaf hydraulic conductance (Kleaf) decreases with increasing water stress, which is due to xylem embolism in leaf veins and/or the properties of the extra-xylary pathway. Water flow through living tissues is facilitated and regulated by water channel proteins called aquaporins (AQPs). Here we assessed changes in the hydraulic conductance of Populus trichocarpa leaves during a dehydration-rewatering episode. While leaves were highly sensitive to drought, Kleaf recovered only 2 hours after plants were rewatered. Recovery of Kleaf was absent when excised leaves were bench-dried and subsequently xylem-perfused with a solution containing AQP inhibitors. We examined the expression patterns of 12 highly expressed AQP genes during a dehydration-rehydration episode to identify isoforms that may be involved in leaf hydraulic adjustments. Among the AQPs tested, several genes encoding tonoplast intrinsic proteins (TIPs) showed large increases in expression in rehydrated leaves, suggesting that TIPs contribute to reversing drought-induced reductions in Kleaf. TIPs were localized in xylem parenchyma, consistent with a role in facilitating water exchange between xylem vessels and adjacent living cells. Dye uptake experiments suggested that reversible embolism formation in minor leaf veins contributed to the observed changes in Kleaf.

  1. Characterization of a plant leaf cuticle model wax, phase behaviour of model wax–water systems

    Energy Technology Data Exchange (ETDEWEB)

    Fagerström, Anton, E-mail: anton.fagerstrom@mah.se [Biomedical Science, Faculty of Health and Society, Malmö University, Malmö (Sweden); Kocherbitov, Vitaly [Biomedical Science, Faculty of Health and Society, Malmö University, Malmö (Sweden); Westbye, Peter; Bergström, Karin [Agro Applications Europe, AkzoNobel Surface Chemistry AB, Stenungsund (Sweden); Mamontova, Varvara [Ecological and Chemical Research, St. Petersburg Scientific Research Center for Ecological Safety, Russian Academy of Sciences, St. Petersburg (Russian Federation); Engblom, Johan [Biomedical Science, Faculty of Health and Society, Malmö University, Malmö (Sweden)

    2013-11-10

    Highlights: • Four individual crystalline phases were discovered in the model wax–water system. • Eutectic melting occurred in both dry and hydrated model wax. • The total transition enthalpy is smaller for the cuticle wax than for the model wax. • Water has a large plasticizing effect on cuticle wax. • The thermotropic transitions of model wax fit in the window of extracted leaf waxes. - Abstract: We investigated the thermotropic phase behaviour of plant leaf intracuticular wax and two representatives of its main components, 1-docosanol (C{sub 22}H{sub 45}OH) and dotriacontane (C{sub 32}H{sub 66}), in dry and hydrated state. One objective was to obtain a model wax, which can be used to estimate formulations effects on cuticle diffusivity in vitro. The two wax components were chosen based on results from Gas Chromatography coupled to Mass Spectrometry analysis of cuticular wax. The wax was extracted from Clivia Miniata Regel leaves and contained 68% primary alcohols (C{sub 16}–C{sub 32}) and 16% n-alkanes (C{sub 21}–C{sub 33}). Differential Scanning Calorimetry, Polarized Light Microscopy and Small- and Wide Angle X-ray Diffraction were used to characterize the cuticular extract and the phase behaviour of the C{sub 22}H{sub 45}OH/C{sub 32}H{sub 66}/H{sub 2}O model system. Four individual crystalline phases were discovered in the model wax–water system and eutectic melting occurred in both dry and hydrated state. The thermotropic transitions of the model wax occur within the broader transition region of the extracted leaf wax.

  2. Leaf water relations and net gas exchange responses of salinized Carrizo citrange seedlings during drought stress and recovery.

    Science.gov (United States)

    Pérez-Pérez, J G; Syvertsen, J P; Botía, P; García-Sánchez, F

    2007-08-01

    Since salinity and drought stress can occur together, an assessment was made of their interacting effects on leaf water relations, osmotic adjustment and net gas exchange in seedlings of the relatively chloride-sensitive Carrizo citrange, Citrus sinensis x Poncirus trifoliata. Plants were fertilized with nutrient solution with or without additional 100 mm NaCl (salt and no-salt treatments). After 7 d, half of the plants were drought stressed by withholding irrigation water for 10 d. Thus, there were four treatments: salinized and non-salinized plants under drought-stress or well-watered conditions. After the drought period, plants from all stressed treatments were re-watered with nutrient solution without salt for 8 d to study recovery. Leaf water relations, gas exchange parameters, chlorophyll fluorescence, proline, quaternary ammonium compounds and leaf and root concentrations of Cl(-) and Na(+) were measured. Salinity increased leaf Cl(-) and Na(+) concentrations and decreased osmotic potential (Psi(pi)) such that leaf relative water content (RWC) was maintained during drought stress. However, in non-salinized drought-stressed plants, osmotic adjustment did not occur and RWC decreased. The salinity-induced osmotic adjustment was not related to any accumulation of proline, quaternary ammonium compounds or soluble sugars. Net CO(2) assimilation rate (A(CO2)) was reduced in leaves from all stressed treatments but the mechanisms were different. In non-salinized drought-stressed plants, lower A(CO2) was related to low RWC, whereas in salinized plants decreased A(CO2) was related to high levels of leaf Cl(-) and Na(+). A(CO2) recovered after irrigation in all the treatments except in previously salinized drought-stressed leaves which had lower RWC and less chlorophyll but maintained high levels of Cl(-), Na(+) and quaternary ammonium compounds after recovery. High leaf levels of Cl(-) and Na(+) after recovery apparently came from the roots. Plants preconditioned by

  3. ‘Breath figures’ on leaf surfaces – formation and effects of microscopic leaf wetness

    Directory of Open Access Journals (Sweden)

    Jürgen eBurkhardt

    2013-10-01

    Full Text Available ‘Microscopic leaf wetness’ means minute amounts of persistent liquid water on leaf surfaces which are invisible to the naked eye. The water is mainly maintained by transpired water vapor condensing onto the leaf surface and to attached leaf surface particles. With an estimated average thickness of less than 1 µm, microscopic leaf wetness it is about 2 orders of magnitude thinner than morning dewfall. The most important physical processes which reduce the saturation vapor pressure and promote condensation are cuticular absorption and the deliquescence of hygroscopic leaf surface particles. Deliquescent salts form highly concentrated solutions. Depending on the amount and concentration of the dissolved ions, the physicochemical properties of microscopic leaf wetness can be considerably different from those of pure water. Microscopic leaf wetness can form continuous thin layers on hydrophobic leaf surfaces and in specific cases can act similar to surfactants, enabling a strong potential influence on the foliar exchange of ions. Microscopic leaf wetness can also enhance the dissolution, the emission, and the reaction of specific atmospheric trace gases e.g. ammonia, SO2, or ozone, leading to a strong potential role for microscopic leaf wetness in plant/atmosphere interaction. Due to its difficult detection, there is little knowledge about the occurrence and the properties of microscopic leaf wetness. However, based on the existing evidence and on physicochemical reasoning it can be hypothesized that microscopic leaf wetness occurs on almost any plant worldwide and often permanently, and that it significantly influences the exchange processes of the leaf surface with its neighboring compartments, i.e., the plant interior and the atmosphere. The omission of microscopic water in general leaf wetness concepts has caused far-reaching, misleading conclusions in the past.

  4. Leaf area compounds height-related hydraulic costs of water transport in Oregon White Oak trees.

    Science.gov (United States)

    N. Phillips; B. J. Bond; N. G. McDowell; Michael G. Ryan; A. Schauer

    2003-01-01

    The ratio of leaf to sapwood area generally decreases with tree size, presumably to moderate hydraulic costs of tree height. This study assessed consequences of tree size and leaf area on water flux in Quercus garryana Dougl. ex. Hook (Oregon White Oak), a species in which leaf to sapwood area ratio increases with tree size. We tested hypotheses that...

  5. CLD1/SRL1 modulates leaf rolling by affecting cell wall formation, epidermis integrity and water homeostasis in rice.

    Science.gov (United States)

    Li, Wen-Qiang; Zhang, Min-Juan; Gan, Peng-Fei; Qiao, Lei; Yang, Shuai-Qi; Miao, Hai; Wang, Gang-Feng; Zhang, Mao-Mao; Liu, Wen-Ting; Li, Hai-Feng; Shi, Chun-Hai; Chen, Kun-Ming

    2017-12-01

    Leaf rolling is considered as one of the most important agronomic traits in rice breeding. It has been previously reported that SEMI-ROLLED LEAF 1 (SRL1) modulates leaf rolling by regulating the formation of bulliform cells in rice (Oryza sativa); however, the regulatory mechanism underlying SRL1 has yet to be further elucidated. Here, we report the functional characterization of a novel leaf-rolling mutant, curled leaf and dwarf 1 (cld1), with multiple morphological defects. Map-based cloning revealed that CLD1 is allelic with SRL1, and loses function in cld1 through DNA methylation. CLD1/SRL1 encodes a glycophosphatidylinositol (GPI)-anchored membrane protein that modulates leaf rolling and other aspects of rice growth and development. The cld1 mutant exhibits significant decreases in cellulose and lignin contents in secondary cell walls of leaves, indicating that the loss of function of CLD1/SRL1 affects cell wall formation. Furthermore, the loss of CLD1/SRL1 function leads to defective leaf epidermis such as bulliform-like epidermal cells. The defects in leaf epidermis decrease the water-retaining capacity and lead to water deficits in cld1 leaves, which contribute to the main cause of leaf rolling. As a result of the more rapid water loss and lower water content in leaves, cld1 exhibits reduced drought tolerance. Accordingly, the loss of CLD1/SRL1 function causes abnormal expression of genes and proteins associated with cell wall formation, cuticle development and water stress. Taken together, these findings suggest that the functional roles of CLD1/SRL1 in leaf-rolling regulation are closely related to the maintenance of cell wall formation, epidermal integrity and water homeostasis. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  6. Photodegradation of Leaf Litter in Water-Limited Ecosystems

    Science.gov (United States)

    Cory, R. M.; Powers, H.; McDowell, N.; Rahn, T.

    2008-12-01

    The longstanding view of terrestrial decomposition holds that heterotrophic respiration drives release of CO2, but recent studies, such as Austin and Vivanco (2006) have shown that in water-limited environments, photochemical decomposition of leaf litter may be equally or more effective than microbial decomposition. Although initial studies have concluded that photochemical degradation can be important in some environments, it has been difficult to quantify and the oxidative mechanisms involved remain unknown. Thus, the objectives of our study were to (1) quantify the CO2 emitted during photochemical degradation of leaf litter and (2) use the stable isotopic signatures of evolved CO2 to elucidate pathways of production. Emitted CO2 and its isotopic signature were measured using a tunable diode laser (TDL) to assess the pool of photochemically-labile plant matter (δ13C-CO2) in a given sample and to assess the source of the oxygen (δ18O-CO2). We quantified the photochemical release of CO2 and its isotopic signature from dried leaf litter of 10 tree and grass species prevalent in major biotic zones of New Mexico. The cumulative CO2 released upon exposure of 0.1-0.3 g of dried leaf litter to three hours of simulated sunlight ranged from 8-25 mg CO2-C g-1 dried litter, corresponding to 1-2% mass loss. Generally, the δ13C-CO2 was more depleted (4-7 ± 2 per mil) than the average δ13C of the respective leaf litter sample. The δ18O-CO2 evolved is approximately equal to δ18O of atmospheric O2, suggesting that the oxidation mechanism involves direct reaction with atmospheric O2.

  7. Remote sensing of leaf, canopy and vegetation water contents for satellite climate data records

    Science.gov (United States)

    Foliar water content is a dynamic quantity depending on water losses from transpiration and water uptake from the soil. Absorption of shortwave radiation by water is determined by various frequency overtones of fundamental bending and stretching molecular transitions. Leaf water potential and rela...

  8. Determination of total phenolic content and antioxidant activitity of methanol extract of Maranta arundinacea L fresh leaf and tuber

    Science.gov (United States)

    Kusbandari, A.; Susanti, H.

    2017-11-01

    Maranta arundinacea L is one of herbaceous plants in Indonesia which have flavonoid content. Flavonoids has antioxidants activity by inhibition of free radical oxidation reactions. The study aims were to determination total phenolic content and antioxidant activity of methanol extract of fresh leaf and tuber of M. arundinacea L by UV-Vis spectrophotometer. The methanol extracts were obtained with maceration and remaseration method of fresh leaves and tubers. The total phenolic content was assayed with visible spectrophotometric using Folin Ciocalteau reagent. The antioxidant activity was assayed with 1,1-diphenyl-2-picrilhidrazil (DPPH) compared to gallic acid. The results showed that methanol extract of tuber and fresh leaf of M. arundinacea L contained phenolic compound with total phenolic content (TPC) in fresh tuber of 3.881±0.064 (% GAE) and fresh leaf is 6.518±0.163 (% b/b GAE). IC50 value from fresh tuber is 1.780±0.0005 μg/mL and IC50 fresh leaf values of 0.274±0.0004 μg/mL while the standard gallic acid is IC50 of 0.640±0.0002 μg/mL.

  9. Effect of drought stress on leaf soluble sugar content, leaf rolling index and relative water content of proso millet (Panicum miliaceum L. genotypes

    Directory of Open Access Journals (Sweden)

    mohamad javad seghatol eslami

    2009-06-01

    Full Text Available With respect to water shortage in arid and semi- arid regions, the study about drought stress effects on crop plants and selection of resistance cultivars, are among the most important goals in the agricultural researches. In order to examine drought stress effects on millet, an experiment was conducted in Birjand and Sarbisheh, simultaneously. In this experiment, five irrigation treatments (well-watered, drought stress in vegetative stage, in ear emergence stage, in seed filling stage and in vegetative and seed filling stage and five proso millet genotypes (Native, K-C-M.2, K-C-M.4, K-C-M.6 and K-C-M.9 were compared in a split plot design along with three replications. Drought stress increased grain protein content, leaf rolling index and soluble sugars concentration and decreased seed germination and leaf RWC. Although seed protein content and germination percentage of genotypes were not significantly different, there were some differences among leaf rolling index, RWC and soluble sugar content of these genotypes. The results of this study indicated that leaf sugar content, RWC and leaf rolling index can not be considered as the only parameters for selection of high yield genotypes. Therefore, it is recommended that some other factors should also be used apart from the above mentioned ones.

  10. Plasticity in the Huber value contributes to homeostasis in leaf water relations of a mallee Eucalypt with variation to groundwater depth.

    Science.gov (United States)

    Carter, Jennifer L; White, Donald A

    2009-11-01

    Information on how vegetation adapts to differences in water supply is critical for predicting vegetation survival, growth and water use, which, in turn, has important impacts on site hydrology. Many field studies assess adaptation to water stress by comparing between disparate sites, which makes it difficult to distinguish between physiological or morphological changes and long-term genetic adaptation. When planting trees into new environments, the phenotypic adaptations of a species to water stress will be of primary interest. This study examined the response to water availability of Eucalyptus kochii ssp. borealis (C. Gardner) D. Nicolle, commonly integrated with agriculture in south-western Australia for environmental and economic benefits. By choosing a site where the groundwater depth varied but where climate and soil type were the same, we were able to isolate tree response to water supply. Tree growth, leaf area and stand water use were much larger for trees over shallow groundwater than for trees over a deep water table below a silcrete hardpan. However, water use on a leaf area basis was similar in trees over deep and shallow groundwater, as were the minimum leaf water potential observed over different seasons and the turgor loss point. We conclude that homeostasis in leaf water use and water relations was maintained through a combination of stomatal control and adjustment of sapwood-to-leaf area ratios (Huber value). Differences in the Huber value with groundwater depth were associated with different sapwood-specific conductivity and water use on a sapwood area basis. Knowledge of the coordination between water supply, leaf area, sapwood area and leaf transpiration rate for different species will be important when predicting stand water use.

  11. Tuning Transpiration by Interfacial Solar Absorber-Leaf Engineering.

    Science.gov (United States)

    Zhuang, Shendong; Zhou, Lin; Xu, Weichao; Xu, Ning; Hu, Xiaozhen; Li, Xiuqiang; Lv, Guangxin; Zheng, Qinghui; Zhu, Shining; Wang, Zhenlin; Zhu, Jia

    2018-02-01

    Plant transpiration, a process of water movement through a plant and its evaporation from aerial parts especially leaves, consumes a large component of the total continental precipitation (≈48%) and significantly influences global water distribution and climate. To date, various chemical and/or biological explorations have been made to tune the transpiration but with uncertain environmental risks. In recent years, interfacial solar steam/vapor generation is attracting a lot of attention for achieving high energy transfer efficiency. Various optical and thermal designs at the solar absorber-water interface for potential applications in water purification, seawater desalination, and power generation appear. In this work, the concept of interfacial solar vapor generation is extended to tunable plant transpiration by showing for the first time that the transpiration efficiency can also be enhanced or suppressed through engineering the solar absorber-leaf interface. By tuning the solar absorption of membrane in direct touch with green leaf, surface temperature of green leaf will change accordingly because of photothermal effect, thus the transpiration efficiency as well as temperature and relative humidity in the surrounding environment will be tuned. This tunable transpiration by interfacial absorber-leaf engineering can open an alternative avenue to regulate local atmospheric temperature, humidity, and eventually hydrologic cycle.

  12. Tuning Transpiration by Interfacial Solar Absorber‐Leaf Engineering

    Science.gov (United States)

    Zhuang, Shendong; Zhou, Lin; Xu, Weichao; Xu, Ning; Hu, Xiaozhen; Li, Xiuqiang; Lv, Guangxin; Zheng, Qinghui; Zhu, Shining

    2017-01-01

    Abstract Plant transpiration, a process of water movement through a plant and its evaporation from aerial parts especially leaves, consumes a large component of the total continental precipitation (≈48%) and significantly influences global water distribution and climate. To date, various chemical and/or biological explorations have been made to tune the transpiration but with uncertain environmental risks. In recent years, interfacial solar steam/vapor generation is attracting a lot of attention for achieving high energy transfer efficiency. Various optical and thermal designs at the solar absorber–water interface for potential applications in water purification, seawater desalination, and power generation appear. In this work, the concept of interfacial solar vapor generation is extended to tunable plant transpiration by showing for the first time that the transpiration efficiency can also be enhanced or suppressed through engineering the solar absorber–leaf interface. By tuning the solar absorption of membrane in direct touch with green leaf, surface temperature of green leaf will change accordingly because of photothermal effect, thus the transpiration efficiency as well as temperature and relative humidity in the surrounding environment will be tuned. This tunable transpiration by interfacial absorber‐leaf engineering can open an alternative avenue to regulate local atmospheric temperature, humidity, and eventually hydrologic cycle. PMID:29619300

  13. Development of pressurised hot water extraction (PHWE) for essential compounds from Moringa oleifera leaf extracts.

    Science.gov (United States)

    Matshediso, Phatsimo G; Cukrowska, Ewa; Chimuka, Luke

    2015-04-01

    Pressurised hot water extraction (PHWE) is a "green" technology which can be used for the extraction of essential components in Moringa oleifera leaf extracts. The behaviour of three flavonols (myricetin, quercetin and kaempferol) and total phenolic content (TPC) in Moringa leaf powder were investigated at various temperatures using PHWE. The TPC of extracts from PHWE were investigated using two indicators. These are reducing activity and the radical scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH). Flavonols content in the PHWE extracts were analysed on high performance liquid chromatography with ultra violet (HPLC-UV) detection. The concentration of kaempferol and myricetin started decreasing at 150 °C while that of quercetin remained steady with extraction temperature. Optimum extraction temperature for flavonols and DPPH radical scavenging activity was found to be 100 °C. The TPC increased with temperature until 150 °C and then decreased while the reducing activity increased. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Factors controlling plasticity of leaf morphology in Robinia pseudoacacia: III. biophysical constraints on leaf expansion under long-term water stress

    Science.gov (United States)

    Yanxiang ​Zhang; Maria Alejandra Equiza; Quanshui Zheng; Melvin T. Tyree

    2011-01-01

    In this article, we measured the relative growth rate (RGR) of leaves of Robinia pseudoacacia seedlings under well-watered and water-stressed conditions (mid-day Ψw = leaf water potential estimated with a pressure bomb of −0.48 and −0.98 MPa, respectively). Pressure–volume (PV) curves were done on growing leaves at 25, 50 and 95% of the mature size...

  15. Transpiration and leaf growth of potato clones in response to soil water deficit

    Directory of Open Access Journals (Sweden)

    André Trevisan de Souza

    2014-04-01

    Full Text Available Potato (Solanum tuberosum ssp. Tuberosum crop is particularly susceptible to water deficit because of its small and shallow root system. The fraction of transpirable soil water (FTSW approach has been widely used in the evaluation of plant responses to water deficit in different crops. The FTSW 34 threshold (when stomatal closure starts is a trait of particular interest because it is an indicator of tolerance to water deficit. The FTSW threshold for decline in transpiration and leaf growth was evaluated in a drying soil to identify potato clones tolerant to water deficit. Two greenhouse experiments were carried out in pots, with three advanced clones and the cultivar Asterix. The FTSW, transpiration and leaf growth were measured on a daily basis, during the period of soil drying. FTSW was an efficient method to separate potato clones with regard to their response to water deficit. The advancedclones SMINIA 02106-11 and SMINIA 00017-6 are more tolerant to soil water deficit than the cultivar Asterix, and the clone SMINIA 793101-3 is more tolerant only under high solar radiation.

  16. Peach leaf responses to soil and cement dust pollution.

    Science.gov (United States)

    Maletsika, Persefoni A; Nanos, George D; Stavroulakis, George G

    2015-10-01

    Dust pollution can negatively affect plant productivity in hot, dry and with high irradiance areas during summer. Soil or cement dust were applied on peach trees growing in a Mediterranean area with the above climatic characteristics. Soil and cement dust accumulation onto the leaves decreased the photosynthetically active radiation (PAR) available to the leaves without causing any shade effect. Soil and mainly cement dust deposition onto the leaves decreased stomatal conductance, photosynthetic and transpiration rates, and water use efficiency due possibly to stomatal blockage and other leaf cellular effects. In early autumn, rain events removed soil dust and leaf functions partly recovered, while cement dust created a crust partially remaining onto the leaves and causing more permanent stress. Leaf characteristics were differentially affected by the two dusts studied due to their different hydraulic properties. Leaf total chlorophyll decreased and total phenol content increased with dust accumulation late in the summer compared to control leaves due to intense oxidative stress. The two dusts did not cause serious metal imbalances to the leaves, except of lower leaf K content.

  17. Stomatal closure of Pelargonium × hortorum in response to soil water deficit is associated with decreased leaf water potential only under rapid soil drying.

    Science.gov (United States)

    Boyle, Richard K A; McAinsh, Martin; Dodd, Ian C

    2016-01-01

    Soil water deficits applied at different rates and for different durations can decrease both stomatal conductance (gs ) and leaf water potential (Ψleaf ). Understanding the physiological mechanisms regulating these responses is important in sustainable irrigation scheduling. Glasshouse-grown, containerized Pelargonium × hortorum BullsEye plants were irrigated either daily at various fractions of plant evapotranspiration (100, 75 and 50% ET) for 20 days or irrigation was withheld for 4 days. Xylem sap was collected and gs and Ψleaf were measured on days 15 and 20, and on days 16-19 for the respective treatments. Xylem sap pH and NO3 (-) and Ca(2+) concentrations did not differ between irrigation treatments. Xylem abscisic acid (ABA) concentrations ([ABA]xyl ) increased within 24 h of irrigation being withheld whilst gs and Ψleaf decreased. Supplying irrigation at a fraction of daily ET produced a similar relationship between [ABA]xyl and gs , but did not change Ψleaf . Treatment differences occurred independently of whether Ψleaf was measured in whole leaves with a pressure chamber, or in the lamina with a thermocouple psychrometer. Plants that were irrigated daily showed lower [ABA]xyl than plants from which irrigation was withheld, even at comparable soil moisture content. This implies that regular re-watering attenuates ABA signaling due to maintenance of soil moisture in the upper soil levels. Crucially, detached leaves supplied with synthetic ABA showed a similar relationship between [ABA]xyl and gs as intact plants, suggesting that stomatal closure of P. hortorum in response to soil water deficit is primarily an ABA-induced response, independent of changes in Ψleaf . © 2015 Scandinavian Plant Physiology Society.

  18. Alpha-glucosidase Inhibitory and Antioxidant Potential of Antidiabetic Herb Alternanthera sessilis: Comparative Analyses of Leaf and Callus Solvent Fractions.

    Science.gov (United States)

    Chai, Tsun-Thai; Khoo, Chee-Siong; Tee, Chong-Siang; Wong, Fai-Chu

    2016-01-01

    Alternanthera sessilis is a medicinal herb which is consumed as vegetable and used as traditional remedies of various ailments in Asia and Africa. This study aimed to investigate the antiglucosidase and antioxidant activity of solvent fractions of A. sessilis leaf and callus. Leaf and callus methanol extracts were fractionated to produce hexane, chloroform, ethyl acetate, butanol, and water fractions. Antiglucosidase and 1,1-diphenyl-2-picrylhydrazyl scavenging activities as well as total phenolic (TP), total flavonoid (TF), and total coumarin (TC) contents were evaluated. Lineweaver-Burk plot analysis was performed on leaf and callus fractions with the strongest antiglucosidase activity. Leaf ethyl acetate fraction (LEF) had the strongest antiglucosidase (EC 50 0.55 mg/mL) and radical scavenging (EC 50 10.81 μg/mL) activity among leaf fractions. Callus ethyl acetate fraction (CEF) and chloroform fraction had the highest antiglucosidase (EC 50 0.25 mg/mL) and radical scavenging (EC 50 34.12 μg/mL) activity, respectively, among callus fractions. LEF and CEF were identified as noncompetitive and competitive α-glucosidase inhibitors, respectively. LEF and CEF had greater antiglucosidase activity than acarbose. Leaf fractions had higher phytochemical contents than callus fractions. LEF had the highest TP, TF, and TC contents. Antiglucosidase and antioxidant activities of leaf fractions correlated with phytochemical contents. LEF had potent antiglucosidase activity and concurrent antioxidant activity. CEF had the highest antiglucosidase activity among all fractions. Callus culture is a promising tool for enhancing production of potent α-glucosidase inhibitors. Leaf ethyl acetate fraction (LEF) had the strongest antiglucosidase (EC 50 0.55 mg/mL) and radical scavenging (EC 50 10.81 μg/mL) activity among leaf fractionsCallus ethyl acetate fraction (CEF) and chloroform fraction had the highest antiglucosidase (EC 50 0.25 mg/mL) and radical scavenging (EC 50 34.12

  19. Plasticity in leaf-level water relations of tropical rainforest trees in response to experimental drought.

    Science.gov (United States)

    Binks, Oliver; Meir, Patrick; Rowland, Lucy; da Costa, Antonio Carlos Lola; Vasconcelos, Steel Silva; de Oliveira, Alex Antonio Ribeiro; Ferreira, Leandro; Christoffersen, Bradley; Nardini, Andrea; Mencuccini, Maurizio

    2016-07-01

    The tropics are predicted to become warmer and drier, and understanding the sensitivity of tree species to drought is important for characterizing the risk to forests of climate change. This study makes use of a long-term drought experiment in the Amazon rainforest to evaluate the role of leaf-level water relations, leaf anatomy and their plasticity in response to drought in six tree genera. The variables (osmotic potential at full turgor, turgor loss point, capacitance, elastic modulus, relative water content and saturated water content) were compared between seasons and between plots (control and through-fall exclusion) enabling a comparison between short- and long-term plasticity in traits. Leaf anatomical traits were correlated with water relation parameters to determine whether water relations differed among tissues. The key findings were: osmotic adjustment occurred in response to the long-term drought treatment; species resistant to drought stress showed less osmotic adjustment than drought-sensitive species; and water relation traits were correlated with tissue properties, especially the thickness of the abaxial epidermis and the spongy mesophyll. These findings demonstrate that cell-level water relation traits can acclimate to long-term water stress, and highlight the limitations of extrapolating the results of short-term studies to temporal scales associated with climate change. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  20. Diurnal depression in leaf hydraulic conductance at ambient and elevated [CO2] and reveals anisohydric water management in field-grown soybean

    Science.gov (United States)

    Diurnal cycles of photosynthesis and water use in field-grown soybean (Glycine max) are tied to light intensity and vapor pressure deficit (VPD). At high mid-day VPD, transpiration rates can lead to a decline in leaf water potential ('leaf) if leaf hydraulic conductance (Kleaf) is insufficient to su...

  1. Modeling stomatal conductance in the earth system: linking leaf water-use efficiency and water transport along the soil-plant-atmosphere continuum

    Science.gov (United States)

    Bonan, G. B.; Williams, M.; Fisher, R. A.; Oleson, K. W.

    2014-09-01

    The Ball-Berry stomatal conductance model is commonly used in earth system models to simulate biotic regulation of evapotranspiration. However, the dependence of stomatal conductance (gs) on vapor pressure deficit (Ds) and soil moisture must be empirically parameterized. We evaluated the Ball-Berry model used in the Community Land Model version 4.5 (CLM4.5) and an alternative stomatal conductance model that links leaf gas exchange, plant hydraulic constraints, and the soil-plant-atmosphere continuum (SPA). The SPA model simulates stomatal conductance numerically by (1) optimizing photosynthetic carbon gain per unit water loss while (2) constraining stomatal opening to prevent leaf water potential from dropping below a critical minimum. We evaluated two optimization algorithms: intrinsic water-use efficiency (ΔAn /Δgs, the marginal carbon gain of stomatal opening) and water-use efficiency (ΔAn /ΔEl, the marginal carbon gain of transpiration water loss). We implemented the stomatal models in a multi-layer plant canopy model to resolve profiles of gas exchange, leaf water potential, and plant hydraulics within the canopy, and evaluated the simulations using leaf analyses, eddy covariance fluxes at six forest sites, and parameter sensitivity analyses. The primary differences among stomatal models relate to soil moisture stress and vapor pressure deficit responses. Without soil moisture stress, the performance of the SPA stomatal model was comparable to or slightly better than the CLM Ball-Berry model in flux tower simulations, but was significantly better than the CLM Ball-Berry model when there was soil moisture stress. Functional dependence of gs on soil moisture emerged from water flow along the soil-to-leaf pathway rather than being imposed a priori, as in the CLM Ball-Berry model. Similar functional dependence of gs on Ds emerged from the ΔAn/ΔEl optimization, but not the ΔAn /gs optimization. Two parameters (stomatal efficiency and root hydraulic

  2. Leaf size indices and structure of the peat swamp forest

    Directory of Open Access Journals (Sweden)

    L.G. Aribal

    2017-12-01

    Full Text Available Leaf size indices of the tree species in the peatland of Agusan del Sur in Mindanao in Philippines was examined to deduce the variation of forest structure and observed forest zonation.  Using raunkiaer and webb’s leaf size classification, the leaf morphometrics of seven tree species consistently found on the established sampling plots were determined.  The species includes Ternstroemia philippinensis Merr., Polyscias aherniana Merr. Lowry and G.M. Plunkett, Calophyllum sclerophyllum Vesque, Fagraea racemosa Jack, Ilex cymosa Blume, Syzygium tenuirame (Miq. Merr. and Tristaniopsis micrantha Merr. Peter G.Wilson and J.T.Waterh.The LSI were correlated against the variables of the peat physico-chemical properties (such as bulk density, acrotelm thickness, peat depth, total organic carbon, nitrogen, phosphorus, and potassium, pH; water (pH, ammonium, nitrate, phosphate; and leaf tissue elements (nitrogen, phosphorus and potassium.  Result showed a decreasing leaf size indices and a three leaf size category consisting of mesophyllous, mesophyllous-notophyllous and microphyllous were observed which corresponds to the structure of vegetation i.e., from the tall-pole forest having the biggest average leaf area of 6,142.29 mm2 to the pygmy forest with average leaf area of 1,670.10 mm2.  Such decreased leaf size indices were strongly correlated to soil nitrogen, acrotelm thickness, peat depth, phosphate in water, nitrogen and phosphorus in the plant tissue.

  3. Modelling non-steady-state isotope enrichment of leaf water in a gas-exchange cuvette environment.

    Science.gov (United States)

    Song, Xin; Simonin, Kevin A; Loucos, Karen E; Barbour, Margaret M

    2015-12-01

    The combined use of a gas-exchange system and laser-based isotope measurement is a tool of growing interest in plant ecophysiological studies, owing to its relevance for assessing isotopic variability in leaf water and/or transpiration under non-steady-state (NSS) conditions. However, the current Farquhar & Cernusak (F&C) NSS leaf water model, originally developed for open-field scenarios, is unsuited for use in a gas-exchange cuvette environment where isotope composition of water vapour (δv ) is intrinsically linked to that of transpiration (δE ). Here, we modified the F&C model to make it directly compatible with the δv -δE dynamic characteristic of a typical cuvette setting. The resultant new model suggests a role of 'net-flux' (rather than 'gross-flux' as suggested by the original F&C model)-based leaf water turnover rate in controlling the time constant (τ) for the approach to steady sate. The validity of the new model was subsequently confirmed in a cuvette experiment involving cotton leaves, for which we demonstrated close agreement between τ values predicted from the model and those measured from NSS variations in isotope enrichment of transpiration. Hence, we recommend that our new model be incorporated into future isotope studies involving a cuvette condition where the transpiration flux directly influences δv . There is an increasing popularity among plant ecophysiologists to use a gas-exchange system coupled to laser-based isotope measurement for investigating non-steady state (NSS) isotopic variability in leaf water (and/or transpiration); however, the current Farquhar & Cernusak (F&C) NSS leaf water model is unsuited for use in a gas-exchange cuvette environment due to its implicit assumption of isotope composition of water vapor (δv ) being constant and independent of that of transpiration (δE ). In the present study, we modified the F&C model to make it compatible with the dynamic relationship between δv and δE as is typically associated

  4. Compared leaf anatomy and water relations of commercial and traditional Prunus dulcis (Mill.) cultivars under rain-fed conditions

    DEFF Research Database (Denmark)

    Oliveira, I.; Meyer, A.; Afonso, S.

    2018-01-01

    Leaf anatomy and water relations of seven almond (Prunus dulcis Mill.) cultivars, traditional (Bonita, Casanova, Parada, Pegarinhos and Verdeal) and commercial (Ferragnès and Glorieta), grown under rain-fed conditions, were studied. The performed measurements included thickness of leaf tissues...... cuticle thickness, while Pegarinhos adds a thicker epidermis and palisade parenchyma to increase protection to water loss. These data is one of the first comparative approaches to the leaf characterization of these cultivars, and should now be combined with physiological and biochemical studies...

  5. Leaf gas exchange performance and the lethal water potential of five European species during drought.

    Science.gov (United States)

    Li, Shan; Feifel, Marion; Karimi, Zohreh; Schuldt, Bernhard; Choat, Brendan; Jansen, Steven

    2016-02-01

    Establishing physiological thresholds to drought-induced mortality in a range of plant species is crucial in understanding how plants respond to severe drought. Here, five common European tree species were selected (Acer campestre L., Acer pseudoplatanus L., Carpinus betulus L., Corylus avellana L. and Fraxinus excelsior L.) to study their hydraulic thresholds to mortality. Photosynthetic parameters during desiccation and the recovery of leaf gas exchange after rewatering were measured. Stem vulnerability curves and leaf pressure-volume curves were investigated to understand the hydraulic coordination of stem and leaf tissue traits. Stem and root samples from well-watered and severely drought-stressed plants of two species were observed using transmission electron microscopy to visualize mortality of cambial cells. The lethal water potential (ψlethal) correlated with stem P99 (i.e., the xylem water potential at 99% loss of hydraulic conductivity, PLC). However, several plants that were stressed beyond the water potential at 100% PLC showed complete recovery during the next spring, which suggests that the ψlethal values were underestimated. Moreover, we observed a 1 : 1 relationship between the xylem water potential at the onset of embolism and stomatal closure, confirming hydraulic coordination between leaf and stem tissues. Finally, ultrastructural changes in the cytoplasm of cambium tissue and mortality of cambial cells are proposed to provide an alternative approach to investigate the point of no return associated with plant death. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Diurnal depression in leaf hydraulic conductance at ambient and elevated [CO2] reveals anisohydric water management in field-grown soybean

    Science.gov (United States)

    Diurnal cycles of photosynthesis and water use in field-grown soybean (Glycine max) are tied to light intensity and vapor pressure deficit (VPD). At high mid-day VPD, transpiration rates can lead to a decline in leaf water potential if leaf hydraulic conductance is insufficient to supply water to in...

  7. Effects of spring prescribed fire on short-term, leaf-level photosynthesis and water use efficiency in longleaf pine

    Science.gov (United States)

    John K. Jackson; Dylan N. Dillaway; Michael C. Tyree; Mary Anne Sword Sayer

    2015-01-01

    Fire is a natural and important environmental disturbance influencing the structure, function, and composition of longleaf pine (Pinus palustris Mill.) ecosystems. However, recovery of young pines to leaf scorch may involve changes in leaf physiology, which could influence leaf water-use efficiency (WUE). This work is part of a larger seasonal...

  8. Can Leaf Spectroscopy Predict Leaf and Forest Traits Along a Peruvian Tropical Forest Elevation Gradient?

    Science.gov (United States)

    Doughty, Christopher E.; Santos-Andrade, P. E.; Goldsmith, G. R.; Blonder, B.; Shenkin, A.; Bentley, L. P.; Chavana-Bryant, C.; Huaraca-Huasco, W.; Díaz, S.; Salinas, N.; Enquist, B. J.; Martin, R.; Asner, G. P.; Malhi, Y.

    2017-11-01

    High-resolution spectroscopy can be used to measure leaf chemical and structural traits. Such leaf traits are often highly correlated to other traits, such as photosynthesis, through the leaf economics spectrum. We measured VNIR (visible-near infrared) leaf reflectance (400-1,075 nm) of sunlit and shaded leaves in 150 dominant species across ten, 1 ha plots along a 3,300 m elevation gradient in Peru (on 4,284 individual leaves). We used partial least squares (PLS) regression to compare leaf reflectance to chemical traits, such as nitrogen and phosphorus, structural traits, including leaf mass per area (LMA), branch wood density and leaf venation, and "higher-level" traits such as leaf photosynthetic capacity, leaf water repellency, and woody growth rates. Empirical models using leaf reflectance predicted leaf N and LMA (r2 > 30% and %RMSE < 30%), weakly predicted leaf venation, photosynthesis, and branch density (r2 between 10 and 35% and %RMSE between 10% and 65%), and did not predict leaf water repellency or woody growth rates (r2<5%). Prediction of higher-level traits such as photosynthesis and branch density is likely due to these traits correlations with LMA, a trait readily predicted with leaf spectroscopy.

  9. Plumbing the depths: extracellular water storage in specialized leaf structures and its functional expression in a three-domain pressure -volume relationship.

    Science.gov (United States)

    Nguyen, Hoa T; Meir, Patrick; Wolfe, Joe; Mencuccini, Maurizio; Ball, Marilyn C

    2017-07-01

    A three-domain pressure-volume relationship (PV curve) was studied in relation to leaf anatomical structure during dehydration in the grey mangrove, Avicennia marina. In domain 1, relative water content (RWC) declined 13% with 0.85 MPa decrease in leaf water potential, reflecting a decrease in extracellular water stored primarily in trichomes and petiolar cisternae. In domain 2, RWC decreased by another 12% with a further reduction in leaf water potential to -5.1 MPa, the turgor loss point. Given the osmotic potential at full turgor (-4.2 MPa) and the effective modulus of elasticity (~40 MPa), domain 2 emphasized the role of cell wall elasticity in conserving cellular hydration during leaf water loss. Domain 3 was dominated by osmotic effects and characterized by plasmolysis in most tissues and cell types without cell wall collapse. Extracellular and cellular water storage could support an evaporation rate of 1 mmol m -2 s -1 for up to 54 and 50 min, respectively, before turgor loss was reached. This study emphasized the importance of leaf anatomy for the interpretation of PV curves, and identified extracellular water storage sites that enable transient water use without substantive turgor loss when other factors, such as high soil salinity, constrain rates of water transport. © 2016 John Wiley & Sons Ltd.

  10. Accumulation of three different sizes of particulate matter on plant leaf surfaces: Effect on leaf traits

    Directory of Open Access Journals (Sweden)

    Chen Xiaoping

    2015-01-01

    Full Text Available Plants not only improve air quality by adsorbing particulate matter (PM on leaf surfaces but can also be affected by their accumulation. In this study, a field investigation was performed in Wuhan, China, into the relationship between seven leaf traits and the accumulation of three different sizes of PM (PM11, PM2.5 and PM0.2 on leaves. The retention abilities of plant leaves with respect to the three sizes of PM differed significantly at different sites and species. The average PM retention capabilities of plant leaves and specific leaf area (SLA were significantly greater in a seriously polluted area, whereas the average values of chlorophyll a (Chl a, chlorophyll b (Chl b, total chlorophyll, carotenoid, pH and relative water content (RWC were greater at the control site. SLA significantly positively correlated with the size of PM, but Chl a, Chl b, total chlorophyll, RWC significantly negatively correlated with the size of PM, whereas the pH did not correlate significantly with the the PM fractions. Additionally, SLA was found to be affected by large particles (PM11, p<0.01; PM2.5 had a more obvious effect on plant leaf traits than the other PM (p<0.05. Overall, the findings from this study provide useful information regarding the selection of plants to reduce atmospheric pollution.

  11. Algorithm for retrieving vegetative canopy and leaf parameters from multi- and hyperspectral imagery

    Science.gov (United States)

    Borel, Christoph

    2009-05-01

    In recent years hyper-spectral data has been used to retrieve information about vegetative canopies such as leaf area index and canopy water content. For the environmental scientist these two parameters are valuable, but there is potentially more information to be gained as high spatial resolution data becomes available. We developed an Amoeba (Nelder-Mead or Simplex) based program to invert a vegetative canopy radiosity model coupled with a leaf (PROSPECT5) reflectance model and modeled for the background reflectance (e.g. soil, water, leaf litter) to a measured reflectance spectrum. The PROSPECT5 leaf model has five parameters: leaf structure parameter Nstru, chlorophyll a+b concentration Cab, carotenoids content Car, equivalent water thickness Cw and dry matter content Cm. The canopy model has two parameters: total leaf area index (LAI) and number of layers. The background reflectance model is either a single reflectance spectrum from a spectral library() derived from a bare area pixel on an image or a linear mixture of soil spectra. We summarize the radiosity model of a layered canopy and give references to the leaf/needle models. The method is then tested on simulated and measured data. We investigate the uniqueness, limitations and accuracy of the retrieved parameters on canopy parameters (low, medium and high leaf area index) spectral resolution (32 to 211 band hyperspectral), sensor noise and initial conditions.

  12. Effect of Mild Water Stress and Enhanced Ultraviolet-B Irradiation on Leaf Growth of Rumex obtusifolius L. and Rumex patientia L. (Polygonaceae).

    OpenAIRE

    Holman, Steven R.

    1981-01-01

    Leaves of Rumex obtusifolius L. and R. patientia L.were exposed to combinations of mild water stress and enhanced ultraviolet-B irradiation during their ontogeny. Two UV-B treatments (enhanced UV-B and control) and three water stress treatments (-0.0 MPa, -0.2 MPa and -0.4 MPa rooting medium matric potentials) were employed. The impact of the stress interaction was assessed on the basis of changes in leaf area, average adaxial epidermal cell size, and total number of adaxial epidermal cells p...

  13. Measurement methods and variability assessment of the Norway spruce total leaf area: Implications for remote sensing

    NARCIS (Netherlands)

    Homolova, L.; Lukes, P.; Malenovsky, Z.; Lhotakova, Z.; Kaplan, V.; Hanus, J.

    2013-01-01

    Estimation of total leaf area (LAT) is important to express biochemical properties in plant ecology and remote sensing studies. A measurement of LAT is easy in broadleaf species, but it remains challenging in coniferous canopies. We proposed a new geometrical model to estimate Norway spruce LAT and

  14. The ability of Abelmoschus manihot L. leaf extract in scavenging of free radical DPPH and total flavonoid determination

    Science.gov (United States)

    Sudewi, S.; Lolo, W. A.; Warongan, M.; Rifai, Y.; Rante, H.

    2017-11-01

    Abelmoschus manihot L. has reported to have flavonoids content. This study aims were to determine the ability of A. manihot extract in counteracting free radical DPPH and determine the content of total flavonoids. A. manihot leaf was taken from 2 regions in North Sulawesi, namely Tomohon and Kotamobagu. The maceration was carried out to extract the active compound in a 96% ethanol solvent. Free radical scavenging analysis was carried out by DPPH and determination of its total flavonoid in the extract was measured using spectrophotometri method. The results showed that A. manihot extract from Tomohon and Kotamobagu could counteract free radical of DPPH with value of free radical activity of 88.151 and 88.801 %, respectively. A. manihot leaf from Kotamobagu has higher total flavonoids content 61.763 mg/g compare to Tomohon 46.679 mg/g which presented as quercetin. A. manihot has antioxidant activity.

  15. Impacts of water stress, environment and rootstock on the diurnal behaviour of stem water potential and leaf conductance in pistachio (Pistacia vera L.)

    International Nuclear Information System (INIS)

    Memmi, H.; Couceiro, J.F.; Gijón, C.; Pérez-López, D.

    2016-01-01

    Little information is available on the diurnal behaviour of water potential and leaf conductance on pistachio trees despite their relevance to fine tune irrigation strategies. Mature pistachio trees were subject to simultaneous measurements of stem water potential (Ψx) and leaf conductance (gl) during the day, at three important periods of the irrigation season. Trees were grown on three different rootstocks and water regimes. An initial baseline relating Ψx to air vapor pressure deficit (VPD) is presented for irrigation scheduling in pistachio. Ψx was closely correlated with VPD but with a different fit according to the degree of water stress. No evidence of the variation of Ψx in relation to the phenology of the tree was observed. Furthermore, midday Ψx showed more accuracy to indicate a situation of water stress than predawn water potential. Under well irrigated conditions, gl was positively correlated with VPD during stage II of growth reaching its peak when VPD reached its maximum value (around 4 kPa). This behaviour changed during stage III of fruit growth suggesting a reliance of stomatal behaviour to the phenological stage independently to the tree water status. The levels of water stress reached were translated in a slow recovery of tree water status and leaf conductance (more than 40 days). Regarding rootstocks, P. integerrima showed little adaptation to water shortage compared to the two other rootstocks under the studied conditions. (Author)

  16. Impacts of water stress, environment and rootstock on the diurnal behaviour of stem water potential and leaf conductance in pistachio (Pistacia vera L.

    Directory of Open Access Journals (Sweden)

    Houssem Memmi

    2016-06-01

    Full Text Available Little information is available on the diurnal behaviour of water potential and leaf conductance on pistachio trees despite their relevance to fine tune irrigation strategies. Mature pistachio trees were subject to simultaneous measurements of stem water potential (Ψx and leaf conductance (gl during the day, at three important periods of the irrigation season. Trees were grown on three different rootstocks and water regimes. An initial baseline relating Ψx to air vapor pressure deficit (VPD is presented for irrigation scheduling in pistachio. Ψx was closely correlated with VPD but with a different fit according to the degree of water stress. No evidence of the variation of Ψx in relation to the phenology of the tree was observed. Furthermore, midday Ψx showed more accuracy to indicate a situation of water stress than predawn water potential. Under well irrigated conditions, gl was positively correlated with VPD during stage II of growth reaching its peak when VPD reached its maximum value (around 4 kPa. This behaviour changed during stage III of fruit growth suggesting a reliance of stomatal behaviour to the phenological stage independently to the tree water status. The levels of water stress reached were translated in a slow recovery of tree water status and leaf conductance (more than 40 days. Regarding rootstocks, P. integerrima showed little adaptation to water shortage compared to the two other rootstocks under the studied conditions.

  17. Impacts of water stress, environment and rootstock on the diurnal behaviour of stem water potential and leaf conductance in pistachio (Pistacia vera L.)

    Energy Technology Data Exchange (ETDEWEB)

    Memmi, H.; Couceiro, J.F.; Gijón, C.; Pérez-López, D.

    2016-11-01

    Little information is available on the diurnal behaviour of water potential and leaf conductance on pistachio trees despite their relevance to fine tune irrigation strategies. Mature pistachio trees were subject to simultaneous measurements of stem water potential (Ψx) and leaf conductance (gl) during the day, at three important periods of the irrigation season. Trees were grown on three different rootstocks and water regimes. An initial baseline relating Ψx to air vapor pressure deficit (VPD) is presented for irrigation scheduling in pistachio. Ψx was closely correlated with VPD but with a different fit according to the degree of water stress. No evidence of the variation of Ψx in relation to the phenology of the tree was observed. Furthermore, midday Ψx showed more accuracy to indicate a situation of water stress than predawn water potential. Under well irrigated conditions, gl was positively correlated with VPD during stage II of growth reaching its peak when VPD reached its maximum value (around 4 kPa). This behaviour changed during stage III of fruit growth suggesting a reliance of stomatal behaviour to the phenological stage independently to the tree water status. The levels of water stress reached were translated in a slow recovery of tree water status and leaf conductance (more than 40 days). Regarding rootstocks, P. integerrima showed little adaptation to water shortage compared to the two other rootstocks under the studied conditions. (Author)

  18. MEASURING LEAF WATER CONTENT USING MULTISPECTRAL TERRESTRIAL LASER SCANNING

    Directory of Open Access Journals (Sweden)

    S. Junttila

    2017-10-01

    Full Text Available Climate change is increasing the amount and intensity of disturbance events, i.e. drought, pest insect outbreaks and fungal pathogens, in forests worldwide. Leaf water content (LWC is an early indicator of tree stress that can be measured remotely using multispectral terrestrial laser scanning (MS-TLS. LWC affects leaf reflectance in the shortwave infrared spectrum which can be used to predict LWC from spatially explicit MS-TLS intensity data. Here, we investigated the relationship between LWC and MS-TLS intensity features at 690 nm, 905 nm and 1550 nm wavelengths with Norway spruce seedlings in greenhouse conditions. We found that a simple ratio of 905 nm and 1550 nm wavelengths was able to explain 84 % of the variation (R2 in LWC with a respective prediction accuracy of 0.0041 g/cm2. Our results showed that MS-TLS can be used to estimate LWC with a reasonable accuracy in environmentally stable conditions.

  19. Measuring Leaf Water Content Using Multispectral Terrestrial Laser Scanning

    Science.gov (United States)

    Junttila, S.; Vastaranta, M.; Linnakoski, R.; Sugano, J.; Kaartinen, H.; Kukko, A.; Holopainen, M.; Hyyppä, H.; Hyyppä, J.

    2017-10-01

    Climate change is increasing the amount and intensity of disturbance events, i.e. drought, pest insect outbreaks and fungal pathogens, in forests worldwide. Leaf water content (LWC) is an early indicator of tree stress that can be measured remotely using multispectral terrestrial laser scanning (MS-TLS). LWC affects leaf reflectance in the shortwave infrared spectrum which can be used to predict LWC from spatially explicit MS-TLS intensity data. Here, we investigated the relationship between LWC and MS-TLS intensity features at 690 nm, 905 nm and 1550 nm wavelengths with Norway spruce seedlings in greenhouse conditions. We found that a simple ratio of 905 nm and 1550 nm wavelengths was able to explain 84 % of the variation (R2) in LWC with a respective prediction accuracy of 0.0041 g/cm2. Our results showed that MS-TLS can be used to estimate LWC with a reasonable accuracy in environmentally stable conditions.

  20. Plant traits and environment: floating leaf blade production and turnover of waterlilies.

    Science.gov (United States)

    Klok, Peter F; van der Velde, Gerard

    2017-01-01

    Floating leaf blades of waterlilies fulfill several functions in wetland ecosystems by production, decomposition and turnover as well as exchange processes. Production and turnover rates of floating leaf blades of three waterlily species, Nuphar lutea (L.) Sm., Nymphaea alba L. and Nymphaea candida Presl, were studied in three freshwater bodies, differing in trophic status, pH and alkalinity. Length and percentages of leaf loss of marked leaf blades were measured weekly during the growing season. Area and biomass were calculated based on leaf length and were used to calculate the turnover rate of floating leaf blades. Seasonal changes in floating leaf production showed that values decreased in the order: Nymphaea alba , Nuphar lutea , Nymphaea candida . The highest production was reached for Nuphar lutea and Nymphaea alba in alkaline, eutrophic water bodies. The production per leaf was relatively high for both species in the acid water body. Nymphaea candida showed a very short vegetation period and low turnover rates. The ratio Total potential leaf biomass/Maximum potential leaf biomass (P/B max ) of the three species ranged from 1.35-2.25. The ratio Vegetation period (Period with floating leaves)/Mean leaf life span ranged from 2.94-4.63, the ratio Growth period (Period with appearance of new floating leaves)/Vegetation period from 0.53-0.73. The clear differences between Nymphaea candida versus Nuphar lutea and Nymphaea alba , may be due to adaptations of Nymphaea candida to an Euro-Siberic climate with short-lasting summer conditions.

  1. Total Water Management - Report

    Science.gov (United States)

    There is a growing need for urban water managers to take a more holistic view of their water resource systems as population growth, urbanization, and current operations put different stresses on the environment and urban infrastructure. Total Water Management (TWM) is an approac...

  2. The Temporal Variation of Leaf Water Potential in Pistachio under Irrigated and Non-Irrigated Conditions

    Directory of Open Access Journals (Sweden)

    Yusuf AYDIN

    2014-09-01

    Full Text Available The present study was carried out in the experimental field of Pistachio Research Institute on pistachio trees which has uzun variety that was 30 years old. The aim of this research was to determine the Leaf Water Potential (LWP of Pistacia vera L. under irrigated and non-irrigated conditions. In the study, the leaf water potential of pistachio was investigated under fully irrigated and non irrigated conditions. The leaf water potential values were measured one day before and after irrigation by using pressure chamber technique at the beginning, mid and end of irrigation season. According to the results obtained from measurements, the LWP value at the beginning of the irrigation season was -3.7 MPa at noon time due to relatively high temperature for both treatments. At the time of pre-dawn and sunset, this value increased and reached to - 1.6 MPa due to relatively low temperature. In general, the LWP values during the mid of irrigation season, in the irrigated treatments, reached to almost -2.5 MPa in the non-irrigated treatment and the value was measured as -3.68 MPa.

  3. Symbiosis with AMF and leaf Pi supply increases water deficit tolerance of woody species from seasonal dry tropical forest.

    Science.gov (United States)

    Frosi, Gabriella; Barros, Vanessa A; Oliveira, Marciel T; Santos, Mariana; Ramos, Diego G; Maia, Leonor C; Santos, Mauro G

    2016-12-01

    In seasonal dry tropical forests, plants are subjected to severe water deficit, and the arbuscular mycorrhizal fungi (AMF) or inorganic phosphorus supply (P i ) can mitigate the effects of water deficit. This study aimed to assess the physiological performance of Poincianella pyramidalis subjected to water deficit in combination with arbuscular mycorrhizal fungi (AMF) and leaf inorganic phosphorus (P i ) supply. The experiment was conducted in a factorial arrangement of 2 water levels (+H 2 O and -H 2 O), 2 AMF levels (+AMF and -AMF) and 2P i levels (+P i and -P i ). Leaf primary metabolism, dry shoot biomass and leaf mineral nutrients were evaluated. Inoculated AMF plants under well-watered and drought conditions had higher photosynthesis and higher shoot biomass. Under drought, AMF, P i or AMF+P i plants showed metabolic improvements in photosynthesis, leaf biochemistry and higher biomass compared to the plants under water deficit without AMF or P i . After rehydration, those plants submitted to drought with AMF, P i or AMF+P i showed a faster recovery of photosynthesis compared to treatment under water deficit without AMF or P i . However, plants under the drought condition with AMF showed a higher net photosynthesis rate. These findings suggest that AMF, P i or AMF+P i increase the drought tolerance in P. pyramidalis, and AMF associations under well-watered conditions increase shoot biomass and, under drought, promoted faster recovery of photosynthesis. Copyright © 2016 Elsevier GmbH. All rights reserved.

  4. Validation of an O-18 leaf water enrichment model

    Energy Technology Data Exchange (ETDEWEB)

    Jaeggi, M.; Saurer, M.; Siegwolf, R.

    2002-03-01

    The seasonal trend in {delta}{sup 18}O{sub ol} in leaf organic matter of spruce needles of mature trees could be modelled for two years. The seasonality was mainly explained by the {delta}{sup 18}O of top-soil water, whereas between years differences were due to variation in air humidity. Application of a third year's data set improved the correlation between modelled and measured {delta}{sup 18}O{sub ol} and thus validated our extended Dongmann model. (author)

  5. Apparent over-investment in leaf venation relaxes leaf morphological constraints on photosynthesis in arid habitats

    Science.gov (United States)

    de Boer, Hugo; Drake, Paul; Veneklaas, Erik

    2017-04-01

    The close relationship between leaf water status and stomatal conductance implies that the hydraulic architecture of leaves poses an important constraint on transpiration, specifically in arid environments with high evaporative demands. However, it remains uncertain how morphological, hydraulic and photosynthetic traits are coordinated to achieve optimal leaf functioning in arid environments. Critical is that leaf veins supply the mesophyll with water that evaporates when stomata are open to allow CO2 uptake for photosynthesis. Theoretical analyses suggest that water is optimally distributed in the mesophyll when the lateral distance between veins (dx) is equal to the distance from these veins to the epidermis (dy), expressed as dx:dy≈1. Although this theory is supported by observations on many derived angiosperms, we hypothesize that plants in arid environments may reduce dx:dy below unity owing to climate-specific functional adaptations of increased leaf thickness and increased vein density. To test our hypothesis we assembled leaf hydraulic, morphological and photosynthetic traits of 68 species from the Eucalyptus and Corymbia genera (termed eucalypts) along an aridity gradient in southwestern Australia. We inferred the potential gas exchange advantage of reducing dx beyond dy using a model that links leaf morphology and hydraulics to photosynthesis. Our observations reveal that eucalypts in arid environments have thick amphistomatous leaves with high vein densities, resulting in dx:dy ratios that range from 1.6 to 0.15 along the aridity gradient. Our model suggests that as leaves become thicker, the effect of reducing dx beyond dy is to offset the reduction in leaf gas exchange that would result from maintaining dx:dy at unity. This apparent over-investment in leaf venation may be explained from the selective pressure of aridity, under which traits associated with long leaf lifespan, high hydraulic and thermal capacitances, and high potential rates of leaf

  6. Induced resistance and gene expression in wheat against leaf rust ...

    African Journals Online (AJOL)

    uvp

    2013-05-15

    associated molecular .... Total RNA was extracted from approximately 0.1 g ground leaf tissue harvested at 0, 24, 48, 72, 96 and ... The RNA was finally dissolved in 100 µl 0.1% (v/v) DMPC treated water. Residual DNA was eliminated ...

  7. Identification of new SSR markers linked to leaf chlorophyll content, flag leaf senescence and cell membrane stability traits in wheat under water stressed condition.

    Science.gov (United States)

    Barakat, Mohamed N; Saleh, Mohamed; Al-Doss, Abdullah A; Moustafa, Khaled A; Elshafei, Adel A; Al-Qurainy, Fahed H

    2015-03-01

    Segregating F4 families from the cross between drought sensitive (Yecora Rojo) and drought tolerant (Pavon 76) genotypes were made to identify SSR markers linked to leaf chlorophyll content, flag leaf senescence and cell membrane stability traits in wheat (Triticum aestivum L.) under water-stressed condition and to map quantitative trait locus (QTL) for the three physiological traits. The parents and 150 F4 families were evaluated phenotypically for drought tolerance using two irrigation treatments (2500 and 7500 m3/ha). Using 400 SSR primers tested for polymorphism in testing parental and F4 families genotypes, the results revealed that QTL for leaf chlorophyll content, flag leaf senescence and cell membrane stability traits were associated with 12, 5 and 12 SSR markers, respectively and explained phenotypic variation ranged from 6 to 42%. The SSR markers for physiological traits had genetic distances ranged from 12.5 to 25.5 cM. These SSR markers can be further used in breeding programs for drought tolerance in wheat.

  8. Leaf water enrichment of stable water isotopes (δ18O and δD) in a mature oil palm plantation in Jambi province, Indonesia.

    Science.gov (United States)

    Bonazza, Mattia; Tjoa, Aiyen; Knohl, Alexander

    2017-04-01

    During the last few decades, Indonesia experienced rapid and large scale land-use change towards intensively managed crops, one of them is oil palm. This transition results in warmer and dryer conditions in microclimate. The impacts on the hydrological cycle and on water-use by plants are, however, not yet completely clear. Water stable isotopes are useful tracers of the hydrological processes and can provide means to partition evapotranspiration into evaporation and transpiration. A key parameter, however, is the enrichment of water stable isotope in plant tissue such as leaves that can provide estimates on the isotopic composition of transpiration. Here we present the results of a field campaign conducted in a mature oil palm plantation in Jambi province, Indonesia. We combined continuous measurements of water vapor isotopic composition and mixing ratio with isotopic analysis of water stored in different pools like oil palm leaves, epiphytes, trunk organic matter and soil collected over a three days period. Leaf enrichment varied from -2 ‰ to 10 ‰ relative to source (ground) water. The temporal variability followed Craig and Gordon model predictions for leaf water enrichment. An improved agreement was reached after considering the Péclet effect with an appropriate value of the characteristic length (L). Measured stomatal conductance (gs) on two different sets of leaves (top and bottom canopy) was mainly controlled by radiation (photosynthetically active radiation) and vapor pressure deficit. We assume that this control could be explained in conditions where soil water content is not representing a limiting factor. Understanding leaf water enrichment provides one step towards partitioning ET.

  9. Plant traits and environment: floating leaf blade production and turnover of waterlilies

    Directory of Open Access Journals (Sweden)

    Peter F. Klok

    2017-04-01

    Full Text Available Floating leaf blades of waterlilies fulfill several functions in wetland ecosystems by production, decomposition and turnover as well as exchange processes. Production and turnover rates of floating leaf blades of three waterlily species, Nuphar lutea (L. Sm., Nymphaea alba L. and Nymphaea candida Presl, were studied in three freshwater bodies, differing in trophic status, pH and alkalinity. Length and percentages of leaf loss of marked leaf blades were measured weekly during the growing season. Area and biomass were calculated based on leaf length and were used to calculate the turnover rate of floating leaf blades. Seasonal changes in floating leaf production showed that values decreased in the order: Nymphaea alba, Nuphar lutea, Nymphaea candida. The highest production was reached for Nuphar lutea and Nymphaea alba in alkaline, eutrophic water bodies. The production per leaf was relatively high for both species in the acid water body. Nymphaea candida showed a very short vegetation period and low turnover rates. The ratio Total potential leaf biomass/Maximum potential leaf biomass (P/Bmax of the three species ranged from 1.35–2.25. The ratio Vegetation period (Period with floating leaves/Mean leaf life span ranged from 2.94–4.63, the ratio Growth period (Period with appearance of new floating leaves/Vegetation period from 0.53–0.73. The clear differences between Nymphaea candida versus Nuphar lutea and Nymphaea alba, may be due to adaptations of Nymphaea candida to an Euro-Siberic climate with short-lasting summer conditions.

  10. Growth and yield response to plant density of water leaf ( Talinum ...

    African Journals Online (AJOL)

    The effects of different planting spaces (15cm x 15cm, 20cm x 20cm, 25cm x 25cm and 30cm x 30cm) on the growth and yield of Talinum triangulare (Water leaf) were investigated in two cropping seasons from 2012 to 2013 (rainy and dry seasons) at University of Port Harcourt Teaching and Research farm, Port Harcourt, ...

  11. Association Mapping of Total Carotenoids in Diverse Soybean Genotypes Based on Leaf Extracts and High-Throughput Canopy Spectral Reflectance Measurements.

    Directory of Open Access Journals (Sweden)

    Arun Prabhu Dhanapal

    Full Text Available Carotenoids are organic pigments that are produced predominantly by photosynthetic organisms and provide antioxidant activity to a wide variety of plants, animals, bacteria, and fungi. The carotenoid biosynthetic pathway is highly conserved in plants and occurs mostly in chromoplasts and chloroplasts. Leaf carotenoids play important photoprotective roles and targeted selection for leaf carotenoids may offer avenues to improve abiotic stress tolerance. A collection of 332 soybean [Glycine max (L. Merr.] genotypes was grown in two years and total leaf carotenoid content was determined using three different methods. The first method was based on extraction and spectrophotometric determination of carotenoid content (eCaro in leaf tissue, whereas the other two methods were derived from high-throughput canopy spectral reflectance measurements using wavelet transformed reflectance spectra (tCaro and a spectral reflectance index (iCaro. An association mapping approach was employed using 31,253 single nucleotide polymorphisms (SNPs to identify SNPs associated with total carotenoid content using a mixed linear model based on data from two growing seasons. A total of 28 SNPs showed a significant association with total carotenoid content in at least one of the three approaches. These 28 SNPs likely tagged 14 putative loci for carotenoid content. Six putative loci were identified using eCaro, five loci with tCaro, and nine loci with iCaro. Three of these putative loci were detected by all three carotenoid determination methods. All but four putative loci were located near a known carotenoid-related gene. These results showed that carotenoid markers can be identified in soybean using extract-based as well as by high-throughput canopy spectral reflectance-based approaches, demonstrating the utility of field-based canopy spectral reflectance phenotypes for association mapping.

  12. Coordination of leaf and stem water transport properties in tropical forest trees

    Science.gov (United States)

    Frederick C. Meinzer; David R. Woodruff; Jean-Christophe Domec; Guillermo Goldstein; Paula I. Campanello; Genoveva M. Gatti; Randol Villalobos-Vega

    2008-01-01

    Stomatal regulation of transpiration constrains leaf water potential (ψ l) within species-specific ranges that presumably avoid excessive tension and embolism in the stem xylem upstream. However, the hydraulic resistance of leaves can be highly variable over short time scales, uncoupling tension in the xylem of leaves from that in the...

  13. Fusaric acid is a crucial factor in the disturbance of leaf water imbalance in Fusarium-infected banana plants.

    Science.gov (United States)

    Dong, Xian; Ling, Ning; Wang, Min; Shen, Qirong; Guo, Shiwei

    2012-11-01

    Fusarium wilt of banana is caused by Fusarium oxysporum f. sp. cubense infection. The initial chlorosis symptoms occur progressively from lower to upper leaves, with wilt symptoms subsequently occurring in the whole plant. To determine the effect of the pathogen infection on the gas exchange characteristics and water content in banana leaves, hydroponic experiments with pathogen inoculation were conducted in a greenhouse. Compared with control plants, infected banana seedlings showed a higher leaf temperature as determined by thermal imaging. Reduced stomatal conductance (g(s)) and transpiration rate (E) in infected plants resulted in lower levels of water loss than in control plants. Water potential in heavily diseased plants (II) was significantly reduced and the E/g(s) ratio was higher than in noninfected plants, indicating the occurrence of uncontrolled water loss not regulated by stomata in diseased plants. As no pathogen colonies were detected from the infected plant leaves, the crude toxin was extracted from the pathogen culture and evaluated about the effect on banana plant to further investigate the probable reason of these physiological changes in Fusarium-infected banana leaf. The phytotoxin fusaric acid (FA) was found in the crude toxin, and both crude toxin and pure FA had similar effects as the pathogen infection on the physiological changes in banana leaf. Additionally, FA was present at all positions in diseased plants and its concentration was positively correlated with the incidence of disease symptoms. Taken together, these observations indicated that FA secreted by the pathogen is an important factor involved in the disturbance of leaf temperature, resulting in uncontrolled leaf water loss and electrolyte leakage due to damaging the cell membrane. In conclusion, FA plays a critical role in accelerating the development of Fusarium wilt in banana plants by acting as a phytotoxin. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  14. Photosynthate partitioning in basal zones of tall fescue leaf blades

    International Nuclear Information System (INIS)

    Allard, G.; Nelson, C.J.

    1991-01-01

    Elongating grass leaves have successive zones of cell division, cell elongation, and cell maturation in the basal portion of the blade and are a strong sink for photosynthate. Our objective was to determine dry matter (DM) deposition and partitioning in basal zones of elongating tall fescue (Festuca arundinacea Schreb.) leaf blades. Vegetative tall fescue plants were grown in continuous light (350 micromoles per square meter per second photosynthetic photon flux density) to obtain a constant spatial distribution of elongation growth with time. Content and net deposition rates of water-soluble carbohydrates (WSC) and DM along elongating leaf blades were determined. These data were compared with accumulation of 14 C in the basal zones following leaf-labeling with 14 CO 2 . Net deposition of DM was highest in the active cell elongation zone, due mainly to deposition of WSC. The maturation zone, just distal to the elongation zone, accounted for 22% of total net deposition of DM in elongating leaves. However, the spatial profile of 14 C accumulation suggested that the elongation zone and the maturation zone were sinks of equal strength. WSC-free DM accounted for 55% of the total net DM deposition in elongating leaf blades, but only 10% of incoming 14 C-photosynthate accumulated in the water-insoluble fraction (WIF ∼ WSC-free DM) after 2 hours. In the maturation zone, more WSC was used for synthesis of WSC-free DM than was imported as recent photosynthate

  15. The effect of strobilurins on leaf gas exchange, water use efficiency and ABA content in grapevine under field conditions.

    Science.gov (United States)

    Diaz-Espejo, Antonio; Cuevas, María Victoria; Ribas-Carbo, Miquel; Flexas, Jaume; Martorell, Sebastian; Fernández, José Enrique

    2012-03-01

    Strobilurins are one of the most important classes of agricultural fungicides. In addition to their anti-fungal effect, strobilurins have been reported to produce simultaneous effects in plant physiology. This study investigated whether the use of strobilurin fungicide improved water use efficiency in leaves of grapevines grown under field conditions in a Mediterranean climate in southern Spain. Fungicide was applied three times in the vineyard and measurements of leaf gas exchange, plant water status, abscisic acid concentration in sap ([ABA]), and carbon isotope composition in leaves were performed before and after applications. No clear effect on stomatal conductance, leaf water potential and intrinsic water use efficiency was found after three fungicide applications. ABA concentration was observed to increase after fungicide application on the first day, vanishing three days later. Despite this transient effect, evolution of [ABA] matched well with the evolution of leaf carbon isotope ratio, which can be used as a surrogate for plant water use efficiency. Morning stomatal conductance was negatively correlated to [ABA]. Yield was enhanced in strobilurin treated plants, whereas fruit quality remained unaltered. Published by Elsevier GmbH.

  16. Beyond leaf color: Comparing camera-based phenological metrics with leaf biochemical, biophysical, and spectral properties throughout the growing season of a temperate deciduous forest

    Science.gov (United States)

    Yang, Xi; Tang, Jianwu; Mustard, John F.

    2014-03-01

    Plant phenology, a sensitive indicator of climate change, influences vegetation-atmosphere interactions by changing the carbon and water cycles from local to global scales. Camera-based phenological observations of the color changes of the vegetation canopy throughout the growing season have become popular in recent years. However, the linkages between camera phenological metrics and leaf biochemical, biophysical, and spectral properties are elusive. We measured key leaf properties including chlorophyll concentration and leaf reflectance on a weekly basis from June to November 2011 in a white oak forest on the island of Martha's Vineyard, Massachusetts, USA. Concurrently, we used a digital camera to automatically acquire daily pictures of the tree canopies. We found that there was a mismatch between the camera-based phenological metric for the canopy greenness (green chromatic coordinate, gcc) and the total chlorophyll and carotenoids concentration and leaf mass per area during late spring/early summer. The seasonal peak of gcc is approximately 20 days earlier than the peak of the total chlorophyll concentration. During the fall, both canopy and leaf redness were significantly correlated with the vegetation index for anthocyanin concentration, opening a new window to quantify vegetation senescence remotely. Satellite- and camera-based vegetation indices agreed well, suggesting that camera-based observations can be used as the ground validation for satellites. Using the high-temporal resolution dataset of leaf biochemical, biophysical, and spectral properties, our results show the strengths and potential uncertainties to use canopy color as the proxy of ecosystem functioning.

  17. Leaf gas exchange, fv/fm ratio, ion content and growth conditions of the two moringa species under magnetic water treatment

    International Nuclear Information System (INIS)

    Hasan, M.M.; Alharby, H.F.; Hajar, A.; Hakeem, K.R.

    2017-01-01

    The current greenhouse experiment investigates the role of magnetic water on the two Moringa species (Moringa oleifera and Moringa peregrina). Both species were exposed to the magnetic field (30 mT). The magnetic water increased the plant height, leaf number, leaflet number, and internode distances in both the species, respectively. Relative water content (RWC) and leaf area in both the species showed changes under magnetic water treatment. The results showed in magnetic water treatment, the leaf gas exchange parameters such as assimilation (A), stomatal conductance (gs), transpiration rate (E), and vapor pressure deficit (VPD) were increased. Similarly, Photosynthetic pigments (Chl a, Chl b, Chl (a+b), Carotenoids), photosynthetic water use efficiency (WUE) were also increased significantly. Magnetized water had also significant effects on the maximal efficiency of PSII photochemistry (Fv/Fm). Our study suggested that magnetic water treatment could be used as an environment-friendly technology for improving the growth and physiology of Moringa species. In addition, this technology could be further incorporated into the traditional methods of agriculture for the improvement of crop plants, particularly in the arid and sub-arid areas of the world. (author)

  18. Determination of dew absorption by coffee plant through deuterium concentrations in leaf water

    Energy Technology Data Exchange (ETDEWEB)

    Leopoldo, P R [Faculdade de Ciencias Medicas e Biologicas de Botucatu (Brazil); Salati, E; Matsui, E [Centro de Energia Nuclear na Agricultura, Piracicaba (Brazil)

    1975-12-01

    The effect of dew falling on leaves on the water metabolism of the coffee plant (Coffea arabica) is examined. The use of natural stable isotopes variations in plant physiological studies is demonstrated. Water extracted from leaf samples is analysed by mass spectrometry. Analyses of deuterium concentrations in water extracted from plant leaves, dew and nutrient solutions are made. Determination of changes in deuterium concentration in the water of leaves from plants exposed to dew, compared with leaves not exposed to dew, is carried out. Results show that during daytime there is an enrichment in deuterium in water contained in the leaves, while at night the opposite occurs.

  19. Determination of dew absorption by coffee plant through deuterium concentrations in leaf water

    International Nuclear Information System (INIS)

    Leopoldo, P.R.; Salati, E.; Matsui, E.

    1975-01-01

    The effect of dew falling on leaves on the water metabolism of the coffee plant (Coffea arabica) is examined. The use of natural stable isotopes variations in plant physiological studies is demonstrated. Water extracted from leaf samples is analysed by mass spectrometry. Analyses of deuterium concentrations in water extracted from plant leaves, dew and nutrient solutions are made. Determination of changes in deuterium concentration in the water of leaves from plants exposed to dew, compared with leaves not exposed to dew, is carried out. Results show that during daytime there is an enrichment in deuterium in water contained in the leaves, while at night the opposite occurs [pt

  20. Leaf gas films delay salt entry and enhance underwater photosynthesis and internal aeration of Melilotus siculus submerged in saline water

    DEFF Research Database (Denmark)

    Teakle, Natasha Lea; Colmer, Timothy David; Pedersen, Ole

    2014-01-01

    A combination of flooding and salinity is detrimental to most plants. We studied tolerance of complete submergence in saline water for Melilotus siculus, an annual legume with superhydrophobic leaf surfaces that retain gas films when under water. M. siculus survived complete submergence of 1 week...... at low salinity (up to 50 mol m(-3) NaCl), but did not recover following de-submergence from 100 mol m(-3) NaCl. The leaf gas films protected against direct salt ingress into the leaves when submerged in saline water, enabling underwater photosynthesis even after 3 d of complete submergence. By contrast......, leaves with the gas films experimentally removed suffered from substantial Na(+) and Cl(-) intrusion and lost the capacity for underwater photosynthesis. Similarly, plants in saline water and without gas films lost more K(+) than those with intact gas films. This study has demonstrated that leaf gas...

  1. Water- and nitrogen-dependent alterations in the inheritance mode of transpiration efficiency in winter wheat at the leaf and whole-plant level.

    Science.gov (United States)

    Ratajczak, Dominika; Górny, Andrzej G

    2012-11-01

    The effects of contrasting water and nitrogen (N) supply on the observed inheritance mode of transpiration efficiency (TE) at the flag-leaf and whole-season levels were examined in winter wheat. Major components of the photosynthetic capacity of leaves and the season-integrated efficiency of water use in vegetative and grain mass formation were evaluated in parental lines of various origins and their diallel F(2)-hybrids grown in a factorial experiment under different moisture and N status of the soil. A broad genetic variation was mainly found for the season-long TE measures. The variation range in the leaf photosynthetic indices was usually narrow, but tended to slightly enhance under water and N shortage. Genotype-treatment interaction effects were significant for most characters. No consistency between the leaf- and season-long TE measures was observed. Preponderance of additivity-dependent variance was mainly identified for the season-integrated TE and leaf CO(2) assimilation rate. Soil treatments exhibited considerable influence on the phenotypic expression of gene action for the residual leaf measures. The contribution of non-additive gene effects and degree of dominance tended to increase in water- and N-limited plants, especially for the leaf transpiration rate and stomatal conductance. The results indicate that promise exists to improve the season-integrated TE. However, selection for TE components should be prolonged for later hybrid generations to eliminate the masking of non-additive causes. Such evaluation among families grown under sub-optimal water and nitrogen supply seems to be the most promising strategy in winter wheat.

  2. Specific leaf area estimation from leaf and canopy reflectance through optimization and validation of vegetation indices

    NARCIS (Netherlands)

    Ali, A.M.; Darvishzadeh, R.; Skidmore, A.K.; van Duren, I.C.

    2017-01-01

    Specific leaf area (SLA), which is defined as the leaf area per unit of dry leaf mass is an important component when assessing functional diversity and plays a key role in ecosystem modeling, linking plant carbon and water cycles as well as quantifying plant physiological processes. However, studies

  3. Joint Leaf chlorophyll and leaf area index retrieval from Landsat data using a regularized model inversion system

    Science.gov (United States)

    Leaf area index (LAI) and leaf chlorophyll (Chl) content represent key biophysical and biochemical controls on water, energy and carbon exchange processes in the terrestrial biosphere. In combination, LAI and leaf Chl content provide critical information on vegetation density, vitality and photosynt...

  4. Apparent Overinvestment in Leaf Venation Relaxes Leaf Morphological Constraints on Photosynthesis in Arid Habitats1[OPEN

    Science.gov (United States)

    de Boer, Hugo J.; Drake, Paul L.; Wendt, Erin; Price, Charles A.; Schulze, Ernst-Detlef; Turner, Neil C.; Nicolle, Dean

    2016-01-01

    Leaf veins supply the mesophyll with water that evaporates when stomata are open to allow CO2 uptake for photosynthesis. Theoretical analyses suggest that water is optimally distributed in the mesophyll when the lateral distance between veins (dx) is equal to the distance from these veins to the epidermis (dy), expressed as dx:dy ≈ 1. Although this theory is supported by observations of many derived angiosperms, we hypothesize that plants in arid environments may reduce dx:dy below unity owing to climate-specific functional adaptations of increased leaf thickness and increased vein density. To test our hypothesis, we assembled leaf hydraulic, morphological, and photosynthetic traits of 68 species from the Eucalyptus and Corymbia genera (termed eucalypts) along an aridity gradient in southwestern Australia. We inferred the potential gas-exchange advantage of reducing dx beyond dy using a model that links leaf morphology and hydraulics to photosynthesis. Our observations reveal that eucalypts in arid environments have thick amphistomatous leaves with high vein densities, resulting in dx:dy ratios that range from 1.6 to 0.15 along the aridity gradient. Our model suggests that, as leaves become thicker, the effect of reducing dx beyond dy is to offset the reduction in leaf gas exchange that would result from maintaining dx:dy at unity. This apparent overinvestment in leaf venation may be explained from the selective pressure of aridity, under which traits associated with long leaf life span, high hydraulic and thermal capacitances, and high potential rates of leaf water transport confer a competitive advantage. PMID:27784769

  5. Phytochemical screening, total phenolics and antioxidant activities of bark and leaf extracts of Goniothalamus velutinus (Airy Shaw from Brunei Darussalam

    Directory of Open Access Journals (Sweden)

    Erum Iqbal

    2015-07-01

    Full Text Available Goniothalamus velutinus Airy Shaw belongs to the family Annonaceae which is known to have anticancer, antitumor and many other bioactivities. Natives of Sabah and Sarawak use root decoction of G. velutinus for the treatment of headache and food poisoning while the bark was used as a mosquito repellent. Bark and leaf extracts of this plant, obtained from Brunei Darussalam, were tested for phytochemical and antioxidant activities. Phytochemical screening of plant extracts revealed the presence of alkaloids, steroids, terpenoids and cardiac glycosides. Quantitative determination of total phenolics, total flavonoids, and various in vitro antioxidant activities (DPPH, ABTS and FRAP of methanolic extract was carried out using colorimetric methods. The total phenolic content, expressed as mg of gallic acid equivalent (GAE per gram of extract, was found to be 68 mg GAE/g and 78 mg GAE/g for bark and leaves respectively. The radical scavenging activity measurement, expressed in terms of EC50 (effective concentration of extract in μg/mL that reduces DPPH absorbance to 50% as compared to negative control, for leaf and bark extracts was found to be 155 μg/mL and 204 μg/mL respectively. Standards trolox and ascorbic acid show EC50 value of 5 μg/mL and 4 μg/mL respectively. Trolox equivalent antioxidant capacity (TEAC was measured using the ABTS and FRAP method. Result for bark and leaf extracts was 79 mg and 106 mg trolox equivalent (TE/g respectively for the ABTS method. For FRAP assay, results for bark and leaf extracts were 80 and 89 mg TE/g respectively.

  6. Penumbra measurements of BeamModulatorTM multi leaf collimator

    International Nuclear Information System (INIS)

    Lu Xiaoguang; Wang Yunlai; Huo Xiaoqing; Sha Xiangyan; Miao Xiongfei

    2010-01-01

    Objective: To evaluate the penumbra of a new multileaf collimator equipped with Elekta Synergy accelerator. Methods: The penumbra were derived from beam profiles measured in air and water using PinPoint ion chamber with PTW MP3 water phantom. Variations of penumbra with X-ray beam energy, depth in water, and leaf position were investigated. Results: The penumbra in air for 6 MV X-ray was 2 mm less than that at depth of maximal dose in water. The penumbra of leaf side was 1 mm less than that of the leaf end. The penumbra had close relationship with beam energy, depth in water and leaf position. penumbra increased with beam quality and water depth. The leaf position had great influence on the penumbra. Conclusions: The penumbra of the multileaf collimator is related to its original design and radiation delivery technique. Special considerations should be taken into during treatment planning. Regular measurement should be performed to guarantee the delivery quality. (authors)

  7. Potencial da água na folha como um indicador de déficit hídrico em milho Leaf water potential as an indicator of water deficit in maize

    Directory of Open Access Journals (Sweden)

    JOÃO ITO BERGONCI

    2000-08-01

    Full Text Available Este trabalho foi desenvolvido na Estação Experimental Agronômica da Universidade Federal do Rio Grande do Sul, localizada no município de Eldorado do Sul, nos anos agrícolas de 1993/94 e 1994/95. O objetivo foi avaliar o potencial da água na folha como indicador do déficit hídrico, em milho (Zea mays L., relacionando-o ao potencial da água no solo. O experimento constou de três níveis de irrigação, desde a capacidade de campo até a ausência de irrigação. Os valores do potencial mínimo da água na folha foram desde -1,2 a -1,5 MPa em plantas irrigadas (na capacidade de campo e de -1,6 a -2,0 MPa em plantas não irrigadas. O potencial mínimo da água na folha correlacionou-se com o potencial matricial da água no solo a 45 cm de profundidade (r² = 0,73, e mostrou ser um indicador adequado de déficit hídrico. O potencial da água na folha ao entardecer mostrou relação com o potencial mínimo da água na folha, indicando, assim, que pode ser utilizado como indicador de déficit hídrico. O potencial foliar de base apresentou diferenças evidentes entre os tratamentos extremos, mas não teve relação consistente com o potencial mínimo da água na folha.This study was carried out at the Agronomic Experimental Station of the Federal University of Rio Grande do Sul, in Eldorado do Sul, RS, Brazil, during the agricultural seasons of 1993/94 and 1994/95. The objective was to evaluate the leaf water potential as an indicator of the water deficit in maize (Zea mays L., and its relation with the soil water potential. The experiment comprised three levels of irrigation, from field capacity to absence of irrigation. The values of the minimum leaf water potential ranged from -1.2 to -1.5 MPa in irrigated plants (field capacity and from -1.6 to -2.0 MPa in nonirrigated plants. The minimum leaf water potential was well correlated to the matric water potential measured at 45 cm deep (r² = 0.73. The sunset leaf water potential showed

  8. Tamarisk Water Flux Patterns Before, During and After Episodic Defoliation by the Salt Cedar Leaf Beetle on the Colorado Plateau, USA

    Science.gov (United States)

    Hultine, K. R.; Nagler, P. L.; Dennison, P. E.

    2008-12-01

    Tamarisk (Tamarix) species are among the most successful plant invaders in the western United States, and has had significant impacts on watershed hydrology and water resources. Accordingly, local, state and federal agencies have undertaken considerable efforts to eradicate tamarisk and restore riparian habitats to pre-invasion status. A biological control - the saltcedar leaf beetle (Diorhabda elongata) - was released in the summer of 2004 at several locations in eastern Utah, USA to control the spread and impact of tamarisk within the Colorado River watershed. Beginning in April of 2008, sap flux techniques were used to monitor changes in transpiration fluxes in response to canopy defoliation by the beetle. Specifically we installed modified (10 mm length) heat dissipation probes into the main stem of 20 mature tamarisk trees within a single stand on the Colorado Plateau. In July, the saltcedar leaf beetle reduced the total leaf area to near 0% of pre-beetle invasion status. Consequently, sap flux declined by up to 80% compared to pre-beetle invasion fluxes. By mid-August, refoliation of the canopy occurred, and sap flux rates returned to pre- defoliation status. Sap flux rates prior to defoliation were modeled against atmospheric vapor pressure deficit in order to predict the amount of water salvage from defoliation. Sap flux from June 1 through September 1 was on average 36% lower than predicted values. Combined with scaling techniques, the heat dissipation approach shows a high potential for monitoring changes in watershed hydrology in response to tamarisk defoliation by the saltcedar leaf beetle. Nevertheless, tamarisk sap flux studies with heat dissipation probes presents several challenges, including, narrow sapwood depth, low flux rates in response to defoliation, and large thermal gradients that are inevitable in warm climates (particularly after defoliation removes canopy shading). We will present results from ongoing research to address these potential

  9. Effect of root pruning and irrigation regimes on leaf water relations and xylem ABA and ionic concentrations in pear trees

    DEFF Research Database (Denmark)

    Wang, Yufei; Bertelsen, Marianne G.; Petersen, Karen Koefoed

    2014-01-01

    relation characteristics, stomatal conductance and xylem sap abscisic acid (ABA) and ionic concentrations. Results showed that leaf water potential, leaf turgor and stomatal conductance of root pruning (RP) treatment was significantly lower than those of non-root pruning (NP) treatment indicating that root...

  10. CDOM PRODUCTION BY MANGROVE LEAF LITTER AND SARGASSUM COLONIES IN FLORIDA KEYS COASTAL WATERS

    Science.gov (United States)

    We have investigated the importance of leaf litter from red mangroves (Rhizophora mangle) and living Sargassum plants as sources of chromophoric dissolved organic matter (CDOM) to the coastal ocean waters and coral reef system of the Florida Keys. The magnitude of UVB exposure t...

  11. Correlated evolution of stem and leaf hydraulic traits in Pereskia (Cactaceae).

    Science.gov (United States)

    Edwards, Erika J

    2006-01-01

    Recent studies have demonstrated significant correlations between stem and leaf hydraulic properties when comparing across species within ecological communities. This implies that these traits are co-evolving, but there have been few studies addressing plant water relations within an explicitly evolutionary framework. This study tests for correlated evolution among a suite of plant water-use traits and environmental parameters in seven species of Pereskia (Cactaceae), using phylogenetically independent contrasts. There were significant evolutionary correlations between leaf-specific xylem hydraulic conductivity, Huber Value, leaf stomatal pore index, leaf venation density and leaf size, but none of these traits appeared to be correlated with environmental water availability; only two water relations traits - mid-day leaf water potentials and photosynthetic water use efficiency - correlated with estimates of moisture regime. In Pereskia, it appears that many stem and leaf hydraulic properties thought to be critical to whole-plant water use have not evolved in response to habitat shifts in water availability. This may be because of the extremely conservative stomatal behavior and particular rooting strategy demonstrated by all Pereskia species investigated. These results highlight the need for a lineage-based approach to understand the relative roles of functional traits in ecological adaptation.

  12. Coordination and transport of water and carbohydrates in the coupled soil-root-xylem-phloem leaf system

    Science.gov (United States)

    Katul, Gabriel; Huang, Cheng-Wei

    2017-04-01

    In response to varying environmental conditions, stomatal pores act as biological valves that dynamically adjust their size thereby determining the rate of CO2 assimilation and water loss (i.e., transpiration) to the atmosphere. Although the significance of this biotic control on gas exchange is rarely disputed, representing parsimoniously all the underlying mechanisms responsible for stomatal kinetics remain a subject of some debate. It has been conjectured that stomatal control in seed plants (i.e., angiosperm and gymnosperm) represents a compromise between biochemical demand for CO2 and prevention of excessive water loss. This view has been amended at the whole-plant level, where xylem hydraulics and sucrose transport efficiency in phloem appear to impose additional constraints on gas exchange. If such additional constraints impact stomatal opening and closure, then seed plants may have evolved coordinated photosynthetic-hydraulic-sugar transporting machinery that confers some competitive advantages in fluctuating environmental conditions. Thus, a stomatal optimization model that explicitly considers xylem hydraulics and maximum sucrose transport is developed to explore this coordination in the leaf-xylem-phloem system. The model is then applied to progressive drought conditions. The main findings from the model calculations are that (1) the predicted stomatal conductance from the conventional stomatal optimization theory at the leaf and the newly proposed models converge, suggesting a tight coordination in the leaf-xylem-phloem system; (2) stomatal control is mainly limited by the water supply function of the soil-xylem hydraulic system especially when the water flux through the transpiration stream is significantly larger than water exchange between xylem and phloem; (3) thus, xylem limitation imposed on the supply function can be used to differentiate species with different water use strategy across the spectrum of isohydric to anisohydric behavior.

  13. Quantitative variation in water-use efficiency across water regimes and its relationship with circadian, vegetative, reproductive, and leaf gas-exchange traits.

    Science.gov (United States)

    Edwards, Christine E; Ewers, Brent E; McClung, C Robertson; Lou, Ping; Weinig, Cynthia

    2012-05-01

    Drought limits light harvesting, resulting in lower plant growth and reproduction. One trait important for plant drought response is water-use efficiency (WUE). We investigated (1) how the joint genetic architecture of WUE, reproductive characters, and vegetative traits changed across drought and well-watered conditions, (2) whether traits with distinct developmental bases (e.g. leaf gas exchange versus reproduction) differed in the environmental sensitivity of their genetic architecture, and (3) whether quantitative variation in circadian period was related to drought response in Brassica rapa. Overall, WUE increased in drought, primarily because stomatal conductance, and thus water loss, declined more than carbon fixation. Genotypes with the highest WUE in drought expressed the lowest WUE in well-watered conditions, and had the largest vegetative and floral organs in both treatments. Thus, large changes in WUE enabled some genotypes to approach vegetative and reproductive trait optima across environments. The genetic architecture differed for gas-exchange and vegetative traits across drought and well-watered conditions, but not for floral traits. Correlations between circadian and leaf gas-exchange traits were significant but did not vary across treatments, indicating that circadian period affects physiological function regardless of water availability. These results suggest that WUE is important for drought tolerance in Brassica rapa and that artificial selection for increased WUE in drought will not result in maladaptive expression of other traits that are correlated with WUE.

  14. Influence of leaf vein density and thickness on hydraulic conductance and photosynthesis in rice (Oryza sativa L.) during water stress.

    Science.gov (United States)

    Tabassum, Muhammad Adnan; Zhu, Guanglong; Hafeez, Abdul; Wahid, Muhammad Atif; Shaban, Muhammad; Li, Yong

    2016-11-16

    The leaf venation architecture is an ideal, highly structured and efficient irrigation system in plant leaves. Leaf vein density (LVD) and vein thickness are the two major properties of this system. Leaf laminae carry out photosynthesis to harvest the maximum biological yield. It is still unknown whether the LVD and/or leaf vein thickness determines the plant hydraulic conductance (K plant ) and leaf photosynthetic rate (A). To investigate this topic, the current study was conducted with two varieties under three PEG-induced water deficit stress (PEG-IWDS) levels. The results showed that PEG-IWDS significantly decreased A, stomatal conductance (g s ), and K plant in both cultivars, though the IR-64 strain showed more severe decreases than the Hanyou-3 strain. PEG-IWDS significantly decreased the major vein thickness, while it had no significant effect on LVD. A, g s and K plant were positively correlated with each other, and they were negatively correlated with LVD. A, g s and K plant were positively correlated with the inter-vein distance and major vein thickness. Therefore, the decreased photosynthesis and hydraulic conductance in rice plants under water deficit conditions are related to the decrease in the major vein thickness.

  15. Effects of species-specific leaf characteristics and reduced water availability on fine particle capture efficiency of trees

    International Nuclear Information System (INIS)

    Räsänen, Janne V.; Holopainen, Toini; Joutsensaari, Jorma; Ndam, Collins; Pasanen, Pertti; Rinnan, Åsmund; Kivimäenpää, Minna

    2013-01-01

    Trees can improve air quality by capturing particles in their foliage. We determined the particle capture efficiencies of coniferous Pinus sylvestris and three broadleaved species: Betula pendula, Betula pubescens and Tilia vulgaris in a wind tunnel using NaCl particles. The importance of leaf surface structure, physiology and moderate soil drought on the particle capture efficiencies of the trees were determined. The results confirm earlier findings of more efficient particle capture by conifers compared to broadleaved plants. The particle capture efficiency of P. sylvestris (0.21%) was significantly higher than those of B. pubescens, T. vulgaris and B. pendula (0.083%, 0.047%, 0.043%, respectively). The small leaf size of P. sylvestris was the major characteristic that increased particle capture. Among the broadleaved species, low leaf wettability, low stomatal density and leaf hairiness increased particle capture. Moderate soil drought tended to increase particle capture efficiency of P. sylvestris. -- Highlights: • Coniferous Scots pine was the most efficient particle collector. • Decreasing single leaf size increases particle deposition of the total leaf area. • Hairiness of the leaf increases particle deposition. -- Trees can improve air quality by removing PM 2.5 pollutants carried on the wind at a velocity of 3 m s −1 , the efficiency of which depends on species leaf characteristics and physical factors

  16. Phenotypic selection on leaf water use efficiency and related ecophysiological traits for natural populations of desert sunflowers.

    Science.gov (United States)

    Donovan, Lisa A; Dudley, Susan A; Rosenthal, David M; Ludwig, Fulco

    2007-05-01

    Plant water-use efficiency (WUE) is expected to affect plant fitness and thus be under natural selection in arid habitats. Although many natural population studies have assessed plant WUE, only a few related WUE to fitness. The further determination of whether selection on WUE is direct or indirect through functionally related traits has yielded no consistent results. For natural populations of two desert annual sunflowers, Helianthus anomalus and H. deserticola, we used phenotypic selection analysis with vegetative biomass as the proxy for fitness to test (1) whether there was direct and indirect selection on WUE (carbon isotope ratio) and related traits (leaf N, area, succulence) and (2) whether direct selection was consistent with hypothesized drought/dehydration escape and avoidance strategies. There was direct selection for lower WUE in mesic and dry H. anomalus populations, consistent with dehydration escape, even though it is the longer lived of the two species. For mesic H. anomalus, direct selection favored lower WUE and higher N, suggesting that plants may be "wasting water" to increase N delivery via the transpiration stream. For the shorter lived H. deserticola in the direr habitat, there was indirect selection for lower WUE, inconsistent with drought escape. There was also direct selection for higher leaf N, succulence and leaf size. There was no direct selection for higher WUE consistent with dehydration avoidance in either species. Thus, in these natural populations of two desert dune species higher fitness was associated with some combination direct and indirect selection for lower WUE, higher leaf N and larger leaf size. Our understanding of the adaptive value of plant ecophysiological traits will benefit from further consideration of related traits such as leaf nitrogen and more tests in natural populations.

  17. Climatic Controls on Leaf Nitrogen Content and Implications for Biochemical Modeling.

    Science.gov (United States)

    Tcherednichenko, I. A.; White, M.; Bastidas, L.

    2007-12-01

    Leaf nitrogen (N) content, expressed as percent total nitrogen per unit of leaf dry mass, is a widely used parameter in biochemical modeling, due mainly to its role as a potentially limiting factor for photosynthesis. The amount of nitrogen, however, does not occur in a fixed amount in every leaf, but rather varies continuously with the leaf life cycle, in constant response to soil-root-stem-leaf-climate interactions and demand for growth. Moreover, while broad data on leaf N has become available it is normally measured under ambient conditions with consequent difficulty for distinguishing between genetic and time specific environmental effects. In the present work we: 1) Investigate the theoretical variation of leaf mass, specific heat capacity and leaf thickness of full sun-expanded leaves as a regulatory mechanism to ensure thermal survival along with long-term climatic radiation/temperature gradient; and discuss nitrogen and carbon controls on leaf thickness. 2) Based on possible states of partition between nitrogenous and non-nitrogenous components of a leaf we further derive probability density functions (PDFs) of nitrogen and carbon content and assess the effect of water and nutrient uptake on the PDFs. 3) Translate the results to spatially explicit representation over the conterminous USA at 1 km spatial resolution by providing maximum potential values of leaf N of fully expanded leaf optimally suited for long term climatic averages values and soils conditions. Implications for potential presence of inherently slow/fast growing species are discussed along with suitability of results for use by biochemical models.

  18. Comparison of leaf gas exchange and stable isotope signature of water-soluble compounds along canopy gradients of co-occurring Douglas-fir and European beech.

    Science.gov (United States)

    Bögelein, Rebekka; Hassdenteufel, Martin; Thomas, Frank M; Werner, Willy

    2012-07-01

    Combined δ(13) C and δ(18) O analyses of water-soluble leaf and twig phloem material were used to determine intrinsic water-use efficiency (iWUE) and variability of stomatal conductance at different crown positions in adult European beech (Fagus sylvatica) and Douglas-fir (Pseudotsuga menziesii) trees. Simultaneous gas exchange measurements allowed evaluation of the differences in calculating iWUE from leaf or phloem water-soluble compounds, and comparison with a semi-quantitative dual isotope model to infer variability of net photosynthesis (A(n) ) between the investigated crown positions. Estimates of iWUE from δ(13) C of leaf water-soluble organic matter (WSOM) outperformed the estimates from phloem compounds. In the beech crown, δ(13) C of leaf WSOM coincided clearly with gas exchange measurements. The relationship was not as reliable in the Douglas-fir. The differences in δ(18) O between leaf and phloem material were found to correlate with stomatal conductance. The semi-quantitative model approach was applicable for comparisons of daily average A(n) between different crown positions and trees. Intracanopy gradients were more pronounced in the beech than in the Douglas-fir, which reached higher values of iWUE at the respective positions, particularly under dry air conditions. © 2012 Blackwell Publishing Ltd.

  19. Use of total body electrical conductivity (TOBEC) to determine total body water

    International Nuclear Information System (INIS)

    Cochran, W.; Wong, W.; Sheng, H.P.; Klein, P.; Klish, W.

    1986-01-01

    Total body electrical conductivity (TOBEC) has been introduced as a safe and rapid method to estimate body composition in infants and adults. Recently, a second generation instrument that operates in a scanning mode has been developed. A study was undertaken to calibrate this new instrument and to assess the feasibility of its use in estimating total body water. Six healthy adults, 3 males and 3 females, ranging in age from 25 to 57 years, and in weight from 43.3 to 104.7 kg were analyzed. Simultaneously, determinations of total body water were made by standard dilutional techniques using H 2 18 O. A baseline plasma sample was obtained and 60 mg 18 O/kg was given orally as H 2 18 O. Five hr later, a postdose plasma sample was obtained. The 18 O/ 16 O ratio in the plasma samples was determined as CO 2 by gas-isotope-ratio mass spectrometry and used to calculate the H 2 18 O volume of distribution. The total body water values ranged from 26.35 to 58.02 and represented 51 to 58% of body weight. There was good linear correlation between the total body water measurement and its phase average (TOBEC number) with a linear correlation coefficient of 0.998. The standard error of the estimate was 0.98. In addition to estimating fat and fat-free mass, the TOBEC method also estimates total body water with excellent correlation to physical dilutions methods

  20. Leaf and stem water potential as vine water status indicators, in Tempranillo grapevine, under different water regimes in the Duero valley

    Directory of Open Access Journals (Sweden)

    Jesús Yuste

    2004-03-01

    The measurement of water potential of the leaf has been easier to take, because it is not necessary to cover the leaves prior to taking the measurement (except in the measurement before dawn, in which case one must be in the vineyard at an unpleasant hour. However, using the potential of the xylem it has been possible to make better observations of the differences between treatments, when these differences are not very important.

  1. Acclimation to high CO2 in maize is related to water status and dependent on leaf rank.

    Science.gov (United States)

    Prins, Anneke; Mukubi, Josephine Muchwesi; Pellny, Till K; Verrier, Paul J; Beyene, Getu; Lopes, Marta Silva; Emami, Kaveh; Treumann, Achim; Lelarge-Trouverie, Caroline; Noctor, Graham; Kunert, Karl J; Kerchev, Pavel; Foyer, Christine H

    2011-02-01

    The responses of C(3) plants to rising atmospheric CO(2) levels are considered to be largely dependent on effects exerted through altered photosynthesis. In contrast, the nature of the responses of C(4) plants to high CO(2) remains controversial because of the absence of CO(2) -dependent effects on photosynthesis. In this study, the effects of atmospheric CO(2) availability on the transcriptome, proteome and metabolome profiles of two ranks of source leaves in maize (Zea mays L.) were studied in plants grown under ambient CO(2) conditions (350 +/- 20 µL L(-1) CO(2) ) or with CO(2) enrichment (700 +/- 20 µL L(-1) CO(2) ). Growth at high CO(2) had no effect on photosynthesis, photorespiration, leaf C/N ratios or anthocyanin contents. However, leaf transpiration rates, carbohydrate metabolism and protein carbonyl accumulation were altered at high CO(2) in a leaf-rank specific manner. Although no significant CO(2) -dependent changes in the leaf transcriptome were observed, qPCR analysis revealed that the abundance of transcripts encoding a Bowman-Birk protease inhibitor and a serpin were changed by the growth CO(2) level in a leaf rank specific manner. Moreover, CO(2) -dependent changes in the leaf proteome were most evident in the oldest source leaves. Small changes in water status may be responsible for the observed responses to high CO(2,) particularly in the older leaf ranks. © 2010 Blackwell Publishing Ltd.

  2. On the temporal variation of leaf magnetic parameters: seasonal accumulation of leaf-deposited and leaf-encapsulated particles of a roadside tree crown.

    Science.gov (United States)

    Hofman, Jelle; Wuyts, Karen; Van Wittenberghe, Shari; Samson, Roeland

    2014-09-15

    Understanding the accumulation behaviour of atmospheric particles inside tree leaves is of great importance for the interpretation of biomagnetic monitoring results. In this study, we evaluated the temporal variation of the saturation isothermal remanent magnetisation (SIRM) of leaves of a roadside urban Platanus × acerifolia Willd. tree in Antwerp, Belgium. We hereby examined the seasonal development of the total leaf SIRM signal as well as the leaf-encapsulated fraction of the deposited dust, by washing the leaves before biomagnetic analysis. On average 38% of the leaf SIRM signal was exhibited by the leaf-encapsulated particles. Significant correlations were found between the SIRM and the cumulative daily average atmospheric PM10 and PM2.5 measurements. Moreover, a steady increase of the SIRM throughout the in-leaf season was observed endorsing the applicability of biomagnetic monitoring as a proxy for the time-integrated PM exposure of urban tree leaves. Strongest correlations were obtained for the SIRM of the leaf-encapsulated particles which confirms the dynamic nature of the leaf surface-accumulated particles. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Response of three broccoli cultivars to salt stress, in relation to water status and expression of two leaf aquaporins.

    Science.gov (United States)

    Muries, Beatriz; Carvajal, Micaela; Martínez-Ballesta, María Del Carmen

    2013-05-01

    The aim of this study was to compare differences in water relations in the leaves of three broccoli cultivars and differential induction of the expression of PIP2 aquaporin isoforms under salt stress. Although broccoli is known to be moderately tolerant to salinity, scarce information exists about the involvement of leaf aquaporins in its adaptation to salinity. Thus, leaf water relations, leaf cell hydraulic conductivity (Lpc), gas exchange parameters and the PIP2 expression pattern were determined for short- (15 h) and long- (15 days) term NaCl treatments. In the long term, the lower half-time of water exchange in the cells of cv. Naxos, compared with Parthenon and Chronos, and its increased PIP2 abundance may have contributed to its Lpc maintenance. This unmodified Lpc in cv. Naxos under prolonged salinity may have diluted NaCl in the leaves, as suggested by lower Na(+) concentrations in the leaf sap. By contrast, the increase in the half-time of water exchange and the lower PIP2 abundance in cvs. Chronos and Parthenon would have contributed to the reduced Lpc values. In cv. Parthenon, there were no differences between the ε values of control and salt-stressed plants; in consequence, cell turgor was enhanced. Also, the increases in BoPIP2;2 and BoPIP2;3 expression in cv. Chronos for the short-term NaCl treatment suggest that these isoforms are involved in osmotic regulation as downstream factors in this cultivar, in fact, in the short-term, Chronos had a significantly reduced osmotic potential and higher PIP2 isoforms expression.

  4. Activity-Guided Isolation of Antioxidant Compounds from Andrographis stenophylla Leaf

    Directory of Open Access Journals (Sweden)

    Neelaveni Thangavel

    2010-01-01

    Full Text Available The antioxidant potency of various extracts of Andrographis stenophylla leaf was evaluated in vitro using ferric thiocyanate method. Reductive ability and free radical scavenging activity of the extracts were also investigated. Amounts of phenolic compounds in each of the extracts were determined using Folin-Ciocalteau reagent and compared to observe the correlation between antioxidant activities and total phenolic content. Methanol extract exhibited maximum antioxidant activity and was found to contain 2% of total phenolic compounds. Methanol extract was subjected to column chromatographic separation over silica gel G using ethyl acetate: formic acid: acetic acid: water. Fractions thus obtained were screened for their antioxidant activity. Among the eleven fractions screened, fraction C was more active than the standard butylated hydroxyanisole. Fraction C on further fractionation with n-butanol: acetic acid: water afforded two flavanoids namely acacetine and isosakuranetine. Fraction A was also shown to possess good antioxidant activity which was developed using TLC and indicated the presence of a terpenoid, Andrographolide. The structures of the isolated compounds were confirmed by UV, IR, MS, 1H and 13C NMR spectral data. This is the first report wherein Andrographolide, Acacetine and Isosakuranetine are isolated from Andrographis stenophylla leaf.

  5. A Simple Paper-Based Microfluidic Device for the Determination of the Total Amino Acid Content in a Tea Leaf Extract

    Science.gov (United States)

    Cai, Longfei; Wu, Yunying; Xu, Chunxiu; Chen, Zefeng

    2013-01-01

    An experiment was developed to demonstrate a microfluidic device in the analytical chemistry (instrumental analysis) laboratory. Students made the paper-based microfluidic device with a wax pen and a piece of filter paper and used it to determine the total quantity of amino acids in a green tea leaf

  6. Total Water Management, the New Paradigm for Urban Water Systems

    Science.gov (United States)

    There is a growing need for urban water managers to take a more holistic view of their water resource systems as population growth, urbanization, and current resource management practices put different stresses on local water resources and urban infrastructure. Total Water Manag...

  7. Leaf physiology and biomass allocation of backcross hybrid American chestnut (Castanea dentata) seedlings in response to light and water availability.

    Science.gov (United States)

    Brown, Caleb E; Mickelbart, Michael V; Jacobs, Douglass F

    2014-12-01

    Partial canopy cover promotes regeneration of many temperate forest trees, but the consequences of shading on seedling drought resistance are unclear. Reintroduction of blight-resistant American chestnut (Castanea dentata (Marsh.) Borkh.) into eastern North American forests will often occur on water-limited sites and under partial canopy cover. We measured leaf pre-dawn water potential (Ψpd), leaf gas exchange, and growth and biomass allocation of backcross hybrid American chestnut seedlings from three orchard sources grown under different light intensities (76, 26 and 8% full photosynthetically active radiation (PAR)) and subjected to well-watered or mid-season water-stressed conditions. Seedlings in the water-stress treatment were returned to well-watered conditions after wilting to examine recovery. Seedlings growing under medium- and high-light conditions wilted at lower leaf Ψpd than low-light seedlings. Recovery of net photosynthesis (Anet) and stomatal conductance (gs) was greater in low and medium light than in high light. Seed source did not affect the response to water stress or light level in most cases. Between 26 and 8% full PAR, light became limiting to the extent that the effects of water stress had no impact on some growth and morphological traits. We conclude that positive and negative aspects of shading on seedling drought tolerance and recovery are not mutually exclusive. Partial shade may help American chestnut tolerate drought during early establishment through effects on physiological conditioning. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Integrating satellite retrieved leaf chlorophyll into land surface models for constraining simulations of water and carbon fluxes

    KAUST Repository

    Houborg, Rasmus

    2013-07-01

    In terrestrial biosphere models, key biochemical controls on carbon uptake by vegetation canopies are typically assigned fixed literature-based values for broad categories of vegetation types although in reality significant spatial and temporal variability exists. Satellite remote sensing can support modeling efforts by offering distributed information on important land surface characteristics, which would be very difficult to obtain otherwise. This study investigates the utility of satellite based retrievals of leaf chlorophyll for estimating leaf photosynthetic capacity and for constraining model simulations of water and carbon fluxes. © 2013 IEEE.

  9. Effects of drought on leaf gas exchange in an eastern broadleaf deciduous forest

    Science.gov (United States)

    Roman, D. T.; Brzostek, E. R.; Dragoni, D.; Rahman, A. F.; Novick, K. A.; Phillips, R.

    2013-12-01

    Understanding plant physiological adaptations to drought is critical for predicting changes in ecosystem productivity that result from climate variability and future climate change. From 2011-2013, southern Indiana experienced a late growing season drought in 2011, a severe early season drought in 2012, and a wet growing season in 2013 characterized by an absence of water stress with frequent precipitation and milder temperatures. The 2012 drought was unique due to the severity and early onset drought conditions (compared to the more frequent late season drought) and was characterized by a Palmer Drought severity index below -4 and precipitation totals from May - July that were 70% less than the long-term (2000 - 2010) mean. During the 2012 drought, an 11% decline in net ecosystem productivity relative to the long-term mean was observed at the AmeriFlux tower in Morgan Monroe State Forest despite a growing season that started ~25 days earlier. Thus, the objective of this study is to evaluate species-specific contributions to the canopy-scale response to inter-annual variability in water stress. We investigated differences between tree species in their response to climate variability using weekly leaf gas exchange and leaf water potential measurements during the growing seasons of 2011-2013. We used this unique dataset, collected at the top of the canopy with a 25 m boom lift, to evaluate changes in leaf water status and maximum assimilation capacity in the drought versus non-drought years. The leaf-level physiology of oak (Quercus) species appears to be less sensitive to drought than other species (tulip poplar [Liriodendron tulipifera], sassafras [Sassafras albidum] and sugar maple [Acer saccharum]). Preliminary data shows mean canopy leaf water potential for oaks was 30.5% more negative in May-July 2012 versus the same time period in 2013. During these same periods the rate of C assimilation in oaks was reduced by only 3%, whereas other species were reduced by

  10. Leaf morphophysiology of a Neotropical mistletoe is shaped by seasonal patterns of host leaf phenology.

    Science.gov (United States)

    Scalon, Marina Corrêa; Rossatto, Davi Rodrigo; Domingos, Fabricius Maia Chaves Bicalho; Franco, Augusto Cesar

    2016-04-01

    Several mistletoe species are able to grow and reproduce on both deciduous and evergreen hosts, suggesting a degree of plasticity in their ability to cope with differences in intrinsic host functions. The aim of this study was to investigate the influence of host phenology on mistletoe water relations and leaf gas exchange. Mistletoe Passovia ovata parasitizing evergreen (Miconia albicans) hosts and P. ovata parasitizing deciduous (Byrsonima verbascifolia) hosts were sampled in a Neotropical savanna. Photosynthetic parameters, diurnal cycles of stomatal conductance, pre-dawn and midday leaf water potential, and stomatal anatomical traits were measured during the peak of the dry and wet seasons, respectively. P. ovata showed distinct water-use strategies that were dependent on host phenology. For P. ovata parasitizing the deciduous host, water use efficiency (WUE; ratio of photosynthetic rate to transpirational water loss) was 2-fold lower in the dry season than in the wet season; in contrast, WUE was maintained at the same level during the wet and dry seasons in P. ovata parasitizing the evergreen host. Generally, mistletoe and host diurnal cycles of stomatal conductance were linked, although there were clear differences in leaf water potential, with mistletoe showing anisohydric behaviour and the host showing isohydric behaviour. Compared to mistletoes attached to evergreen hosts, those parasitizing deciduous hosts had a 1.4-fold lower stomatal density and 1.2-fold wider stomata on both leaf surfaces, suggesting that the latter suffered less intense drought stress. This is the first study to show morphophysiological differences in the same mistletoe species parasitizing hosts of different phenological groups. Our results provide evidence that phenotypical plasticity (anatomical and physiological) might be essential to favour the use of a greater range of hosts.

  11. FEASIBILITY STUDY OF ANAEROBIC DIGESTION OF OCIMUM SANCTUM LEAF WASTE GENERATED FROM SANCTUM SANCTORUM

    Directory of Open Access Journals (Sweden)

    Korla Swapnavahini

    2010-02-01

    Full Text Available The waste originated in temples is presently piled up at one place and then disposed off in water bodies or dumped on land to decay, leading to water and soil pollution. The present work aims to determine the biogas yield and nutrient reduction potential of Ocimum sanctum (basil leaf waste obtained from temples. Laboratory scale digesters of 2.5 L capacity were used and fed with basil leaf waste, which was digested in a batch reactor for a retention period of 30 days at room temperature. Preliminary results indicate that the process is effective in reducing the pollution potential of the basil waste. The process removed up to 73% and 42% of total solids and BOD, respectively, along with biogas production.

  12. Oxygen isotope fractionations across individual leaf carbohydrates in grass and tree species.

    Science.gov (United States)

    Lehmann, Marco M; Gamarra, Bruno; Kahmen, Ansgar; Siegwolf, Rolf T W; Saurer, Matthias

    2017-08-01

    Almost no δ 18 O data are available for leaf carbohydrates, leaving a gap in the understanding of the δ 18 O relationship between leaf water and cellulose. We measured δ 18 O values of bulk leaf water (δ 18 O LW ) and individual leaf carbohydrates (e.g. fructose, glucose and sucrose) in grass and tree species and δ 18 O of leaf cellulose in grasses. The grasses were grown under two relative humidity (rH) conditions. Sucrose was generally 18 O-enriched compared with hexoses across all species with an apparent biosynthetic fractionation factor (ε bio ) of more than 27‰ relative to δ 18 O LW , which might be explained by isotopic leaf water and sucrose synthesis gradients. δ 18 O LW and δ 18 O values of carbohydrates and cellulose in grasses were strongly related, indicating that the leaf water signal in carbohydrates was transferred to cellulose (ε bio  = 25.1‰). Interestingly, damping factor p ex p x , which reflects oxygen isotope exchange with less enriched water during cellulose synthesis, responded to rH conditions if modelled from δ 18 O LW but not if modelled directly from δ 18 O of individual carbohydrates. We conclude that δ 18 O LW is not always a good substitute for δ 18 O of synthesis water due to isotopic leaf water gradients. Thus, compound-specific δ 18 O analyses of individual carbohydrates are helpful to better constrain (post-)photosynthetic isotope fractionation processes in plants. © 2017 John Wiley & Sons Ltd.

  13. Thermal conductivity of leaf compost used in biofilters: An experimental and theoretical investigation

    International Nuclear Information System (INIS)

    Chandrakanthi, M.; Mehrotra, A.K.; Hettiaratchi, J.P.A.

    2005-01-01

    Thermal conductivity is an important property that governs the behaviour of leaf compost biofilters used in treating gaseous pollutants. Measurements were carried out for the thermal conductivity (K) of 44 samples of leaf compost, covering wide ranges of the volume fractions of water (ξ w ), solids (ξ s ) and air (ξ a ), at 20 deg. C using an unsteady state thermal probe. The results indicated that the compost thermal conductivity increased with an increase in ξ w , with a decrease in ξ a , and with an increase in the degree of saturation (defined as the volumetric fraction of water in the total void space). The predictions from the Woodside-Messmer quadratic parallel (QP) model for the thermal conductivity of leaf compost were higher than the experimental values. A simple linear relationship was developed between the thermal conductivity and the degree of saturation, which provided a satisfactory correlation for the data measured in this study as well as those reported recently for sandy and clay loams. -Thermal conductivity of compost exhibits a linear relationship with the degree of saturation of the matrix

  14. Effects of ultraviolet-B radiation on plants during mild water stress, 4: The insensitivity of soybean internal water relations to ultraviolet-B radiation

    International Nuclear Information System (INIS)

    Teramura, A.H.; Forseth, I.N.; Lydon, J.

    1984-01-01

    The combined effects of ultraviolet-B (UV-B, 280–320 nm) radiation and water stress were investigated on the water relations of greenhouse grown soybean [Glycine max (L.) Merr. cv. Essex]. On a weighted (Caldwell 1971), total daily dose basis, plants received either 0 or 3 000 effective J m 2 UV-B BE supplied by filtered FS-40 sunlamps. The latter dose simulated the solar UV-B radiation anticipated at College Park, Maryland, U.S.A. (39°N latitude) in the event that the global stratospheric ozone column is reduced by 25%. Plants were either well-watered or preconditioned by drought stress cycles. Diurnal measurements of water potential and stomatal conductance were made on the youngest fully expanded leaf. Various internal water relations parameters were determined for detached leaves. Plants were monitored before, during and after water stress. There were no significant differences in leaf water potential or stomatal conductance between treatments before plants were preconditioned to water stress. However, drought stress resulted in significantly lower midday and afternoon leaf water potentials and lower leaf conductances as compared to well-watered plants. UV-B radiation had no additional effect on leaf water potential; however, UV did result in lower leaf conductances in plants preconditioned to water stress. Turgid weight:dry weight ratio, elastic modulus, bound water and relative water content were unaffected by UV-B radiation. Osmotic potentials at full and zero turgor were significantly lower in the drought stressed treatments as compared to well-watered plants. (author)

  15. Effects of mechanical stress or abscisic acid on growth, water status and leaf abscisic acid content of eggplant seedlings

    Science.gov (United States)

    Latimer, J. G.; Mitchell, C. A.

    1988-01-01

    Container-grown eggplant (Solanum melongena L. var esculentum Nees. 'Burpee's Black Beauty') seedlings were conditioned with brief, periodic mechanical stress or abscisic acid (ABA) in a greenhouse prior to outdoor exposure. Mechanical stress consisted of seismic (shaking) or thigmic (stem flexing) treatment. Exogenous ABA (10(-3) or 10(-4)M) was applied as a soil drench 3 days prior to outdoor transfer. During conditioning, only thigmic stress reduced stem elongation and only 10(-3) M ABA reduced relative growth rate (RGR). Both conditioning treatments increased leaf specific chlorophyll content, but mechanical stress did not affect leaf ABA content. Outdoor exposure of unconditioned eggplant seedlings decreased RGR and leaf-specific chlorophyll content, but tended to increase leaf ABA content relative to that of plants maintained in the greenhouse. Conditioning did not affect RGR of plants subsequently transferred outdoors, but did reduce stem growth. Seismic stress applied in the greenhouse reduced dry weight gain by plants subsequently transferred outdoors. Mechanical stress treatments increased leaf water potential by 18-25% relative to that of untreated plants.

  16. Measurement for the MLC leaf velocity profile by considering the leaf leakage using a radiographic film

    International Nuclear Information System (INIS)

    Chow, James C L; Grigorov, Grigor N

    2006-01-01

    A method to measure the velocity profile of a multi-leaf collimator (MLC) leaf along its travel range using a radiographic film is reported by considering the intra-leaf leakage. A specific dynamic MLC field with leaves travelling from the field edge to the isocentre line was designed. The field was used to expose a radiographic film, which was then scanned, and the dose profile along the horizontal leaf axis was measured. The velocity at a sampling point on the film can be calculated by considering the horizontal distance between the sampling point and the isocentre line, dose at the sampling point, dose rate of the linear accelerator, the total leaf travel time from the field edge to isocentre line and the pre-measured dose rate of leaf leakage. With the leaf velocities and velocity profiles for all MLC leaves measured routinely, a comprehensive and simple QA for the MLC can be set up to test the consistency of the leaf velocity performance which is essential to the IMRT delivery using a sliding window technique. (note)

  17. An ATP-binding cassette subfamily G full transporter is essential for the retention of leaf water in both wild barley and rice.

    Science.gov (United States)

    Chen, Guoxiong; Komatsuda, Takao; Ma, Jian Feng; Nawrath, Christiane; Pourkheirandish, Mohammad; Tagiri, Akemi; Hu, Yin-Gang; Sameri, Mohammad; Li, Xinrong; Zhao, Xin; Liu, Yubing; Li, Chao; Ma, Xiaoying; Wang, Aidong; Nair, Sudha; Wang, Ning; Miyao, Akio; Sakuma, Shun; Yamaji, Naoki; Zheng, Xiuting; Nevo, Eviatar

    2011-07-26

    Land plants have developed a cuticle preventing uncontrolled water loss. Here we report that an ATP-binding cassette (ABC) subfamily G (ABCG) full transporter is required for leaf water conservation in both wild barley and rice. A spontaneous mutation, eibi1.b, in wild barley has a low capacity to retain leaf water, a phenotype associated with reduced cutin deposition and a thin cuticle. Map-based cloning revealed that Eibi1 encodes an HvABCG31 full transporter. The gene was highly expressed in the elongation zone of a growing leaf (the site of cutin synthesis), and its gene product also was localized in developing, but not in mature tissue. A de novo wild barley mutant named "eibi1.c," along with two transposon insertion lines of rice mutated in the ortholog of HvABCG31 also were unable to restrict water loss from detached leaves. HvABCG31 is hypothesized to function as a transporter involved in cutin formation. Homologs of HvABCG31 were found in green algae, moss, and lycopods, indicating that this full transporter is highly conserved in the evolution of land plants.

  18. DIFFERENCES IN LEAF GAS EXCHANGE AND LEAF CHARACTERISTICS BETWEEN TWO ALMOND CULTIVARS

    Directory of Open Access Journals (Sweden)

    George D. Nanos

    2013-12-01

    Full Text Available Leaf chlorophyll content, specific leaf weight (SLW, photosynthetic and transpiration rates, stomatal functioning, water use efficiency and quantum yield were assessed during the kernel filling period for two consecutive years in order to understand tissue-centered physiological profile differences between two commercial almond cultivars, ‘Ferragnès’ and ‘Texas’. Similar SLWs were observed on the studied cultivars; however, chlorophyll content, net photosynthetic and transpiration rates and stomatal functioning demonstrated statistically significant differences. In both cultivars, an overall decline in the examined parameters towards fruit maturation (i.e. end of the summer was recorded. ‘Ferragnès’ leaves were found to be more efficient in leaf photosynthesis related performance during kernel filling, when irrigated sufficiently, in comparison to ‘Texas’ leaves. Low average values of leaf conductance during summer in ‘Texas’ leaves revealed its potential for adaptation in cool climates and increased carbon assimilation therein for high kernel yield.

  19. Identification and characterization of hydrocolloid from Cordia myxa leaf.

    Science.gov (United States)

    Samavati, Vahid; Lorestani, Mohammad; Joolazadeh, Sajjad

    2014-04-01

    Hot water extraction technique was employed to extract the hydrocolloid from Cordia myxa leaf (PCM). The optimal conditions for extraction of PCM were determined using response surface methodology. A Box-Behnken design (BBD) was applied to evaluate the effects of three independent variables (extraction time (X1: 1-4 h), extraction temperature (X2: 55-95 °C), and water to raw material ratio (X3: 5-30 ml/g) on the extraction yield of PCM. The content of moisture, water-soluble and water-insoluble ash, crude protein and total phenol were determined in the extracted hydrocolloid by standard methods. The maximum hydrocolloid extraction yield (9.501±0.15%) was achieved by using extraction time of 4.94 h, extraction temperature of 94.91 °C and water to raw material ratio of 21.74 ml/g. The contents of moisture, crude protein, water-soluble and water-insoluble ash and total phenol were 21.63±0.94%, 14.27±0.55%, 3.07±0.16% and 2.61±0.19 mg galic acid/g, respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Total Water Management: The New Paradigm for Urban Water Resources Planning

    Science.gov (United States)

    There is a growing need for urban water managers to take a more holistic view of their water resource systems as population growth, urbanization, and current resource management practices put different stresses on local water resources and urban infrastructure. Total Water Manag...

  1. Retrieval of leaf water content spanning the visible to thermal infrared spectra

    CSIR Research Space (South Africa)

    Ullah, S

    2014-05-01

    Full Text Available ; Hunt and Rock 1989; Sepulcre-Cantó et al. 2006). 45 Retrieving leaf water content using remote sensing data, has been widely investigated in the 46 visible near infrared (VNIR) and shortwave infrared (SWIR) spectra (Thomas et al. 1971; 47 Danson et..., USA: NASA / GSFC 400 Savitzky, A., & Golay, M.J.E. (1964). Smoothing and differentiation of data by simplified Least 401 squares procedures. Analytical Chemistry, 36, 1627-1639 402 Sepulcre-Cantó, G., Zarco-Tejada, P.J., Jiménez-Muñoz, J.C., Sobrino...

  2. Role of soil-to-leaf tritium transfer in controlling leaf tritium dynamics: Comparison of experimental garden and tritium-transfer model results.

    Science.gov (United States)

    Ota, Masakazu; Kwamena, Nana-Owusua A; Mihok, Steve; Korolevych, Volodymyr

    2017-11-01

    Environmental transfer models assume that organically-bound tritium (OBT) is formed directly from tissue-free water tritium (TFWT) in environmental compartments. Nevertheless, studies in the literature have shown that measured OBT/HTO ratios in environmental samples are variable and generally higher than expected. The importance of soil-to-leaf HTO transfer pathway in controlling the leaf tritium dynamics is not well understood. A model inter-comparison of two tritium transfer models (CTEM-CLASS-TT and SOLVEG-II) was carried out with measured environmental samples from an experimental garden plot set up next to a tritium-processing facility. The garden plot received one of three different irrigation treatments - no external irrigation, irrigation with low tritium water and irrigation with high tritium water. The contrast between the results obtained with the different irrigation treatments provided insights into the impact of soil-to-leaf HTO transfer on the leaf tritium dynamics. Concentrations of TFWT and OBT in the garden plots that were not irrigated or irrigated with low tritium water were variable, responding to the arrival of the HTO-plume from the tritium-processing facility. In contrast, for the plants irrigated with high tritium water, the TFWT concentration remained elevated during the entire experimental period due to a continuous source of high HTO in the soil. Calculated concentrations of OBT in the leaves showed an initial increase followed by quasi-equilibration with the TFWT concentration. In this quasi-equilibrium state, concentrations of OBT remained elevated and unchanged despite the arrivals of the plume. These results from the model inter-comparison demonstrate that soil-to-leaf HTO transfer significantly affects tritium dynamics in leaves and thereby OBT/HTO ratio in the leaf regardless of the atmospheric HTO concentration, only if there is elevated HTO concentrations in the soil. The results of this work indicate that assessment models

  3. A non-destructive method for estimating onion leaf area

    Directory of Open Access Journals (Sweden)

    Córcoles J.I.

    2015-06-01

    Full Text Available Leaf area is one of the most important parameters for characterizing crop growth and development, and its measurement is useful for examining the effects of agronomic management on crop production. It is related to interception of radiation, photosynthesis, biomass accumulation, transpiration and gas exchange in crop canopies. Several direct and indirect methods have been developed for determining leaf area. The aim of this study is to develop an indirect method, based on the use of a mathematical model, to compute leaf area in an onion crop using non-destructive measurements with the condition that the model must be practical and useful as a Decision Support System tool to improve crop management. A field experiment was conducted in a 4.75 ha commercial onion plot irrigated with a centre pivot system in Aguas Nuevas (Albacete, Spain, during the 2010 irrigation season. To determine onion crop leaf area in the laboratory, the crop was sampled on four occasions between 15 June and 15 September. At each sampling event, eight experimental plots of 1 m2 were used and the leaf area for individual leaves was computed using two indirect methods, one based on the use of an automated infrared imaging system, LI-COR-3100C, and the other using a digital scanner EPSON GT-8000, obtaining several images that were processed using Image J v 1.43 software. A total of 1146 leaves were used. Before measuring the leaf area, 25 parameters related to leaf length and width were determined for each leaf. The combined application of principal components analysis and cluster analysis for grouping leaf parameters was used to reduce the number of variables from 25 to 12. The parameter derived from the product of the total leaf length (L and the leaf diameter at a distance of 25% of the total leaf length (A25 gave the best results for estimating leaf area using a simple linear regression model. The model obtained was useful for computing leaf area using a non

  4. The effect of vapour pressure deficit on stomatal conductance, sap pH and leaf-specific hydraulic conductance in Eucalyptus globulus clones grown under two watering regimes.

    Science.gov (United States)

    Hernandez, Maria Jose; Montes, Fernando; Ruiz, Federico; Lopez, Gustavo; Pita, Pilar

    2016-05-01

    Stomatal conductance has long been considered of key interest in the study of plant adaptation to water stress. The expected increase in extreme meteorological events under a climate change scenario may compromise survival in Eucalyptus globulus plantations established in south-western Spain. We investigated to what extent changes in stomatal conductance in response to high vapour pressure deficits and water shortage are mediated by hydraulic and chemical signals in greenhouse-grown E. globulus clones. Rooted cuttings were grown in pots and submitted to two watering regimes. Stomatal conductance, shoot water potential, sap pH and hydraulic conductance were measured consecutively in each plant over 4 weeks under vapour pressure deficits ranging 0·42 to 2·25 kPa. Evapotranspiration, growth in leaf area and shoot biomass were also determined. There was a significant effect of both clone and watering regime in stomatal conductance and leaf-specific hydraulic conductance, but not in sap pH. Sap pH decreased as water potential and stomatal conductance decreased under increasing vapour pressure deficit. There was no significant relationship between stomatal conductance and leaf-specific hydraulic conductance. Stomata closure precluded shoot water potential from falling below -1·8 MPa. The percentage loss of hydraulic conductance ranged from 40 to 85 %. The highest and lowest leaf-specific hydraulic conductances were measured in clones from the same half-sib families. Water shortage reduced growth and evapotranspiration, decreases in evapotranspiration ranging from 14 to 32 % in the five clones tested. Changes in sap pH seemed to be a response to changes in atmospheric conditions rather than soil water in the species. Stomata closed after a considerable amount of hydraulic conductance was lost, although intraspecific differences in leaf-specific hydraulic conductance suggest the possibility of selection for improved productivity under water-limiting conditions

  5. Effects of some growth regulating applications on leaf yield, raw ...

    African Journals Online (AJOL)

    This study investigated the effects of repetitive applications of herbagreen (HG), humic acid (HA), combined foliar fertilizer (CFF) and HG+CFF performed in the Müsküle grape variety grafted on 5 BB rootstock on fresh or pickled leaf size and leaf raw cellulose content. HA application increased leaf area and leaf water ...

  6. Short-term responses of leaf growth rate to water deficit scale up to whole-plant and crop levels: an integrated modelling approach in maize.

    Science.gov (United States)

    Chenu, Karine; Chapman, Scott C; Hammer, Graeme L; McLean, Greg; Salah, Halim Ben Haj; Tardieu, François

    2008-03-01

    Physiological and genetic studies of leaf growth often focus on short-term responses, leaving a gap to whole-plant models that predict biomass accumulation, transpiration and yield at crop scale. To bridge this gap, we developed a model that combines an existing model of leaf 6 expansion in response to short-term environmental variations with a model coordinating the development of all leaves of a plant. The latter was based on: (1) rates of leaf initiation, appearance and end of elongation measured in field experiments; and (2) the hypothesis of an independence of the growth between leaves. The resulting whole-plant leaf model was integrated into the generic crop model APSIM which provided dynamic feedback of environmental conditions to the leaf model and allowed simulation of crop growth at canopy level. The model was tested in 12 field situations with contrasting temperature, evaporative demand and soil water status. In observed and simulated data, high evaporative demand reduced leaf area at the whole-plant level, and short water deficits affected only leaves developing during the stress, either visible or still hidden in the whorl. The model adequately simulated whole-plant profiles of leaf area with a single set of parameters that applied to the same hybrid in all experiments. It was also suitable to predict biomass accumulation and yield of a similar hybrid grown in different conditions. This model extends to field conditions existing knowledge of the environmental controls of leaf elongation, and can be used to simulate how their genetic controls flow through to yield.

  7. Does homeostasis or disturbance of homeostasis in minimum leaf water potential explain the isohydric versus anisohydric behavior of Vitis vinifera L. cultivars?

    Science.gov (United States)

    Jean-Christophe Domec; Daniel M. Johnson

    2012-01-01

    Due to the diurnal and seasonal fluctuations in leaf-to-air vapor pressure deficit (D), one of the key regulatory roles played by stomata is to limit transpiration-induced leaf water deficit. Different types of plants are known to vary in the sensitivity of stomatal conductance (gs) to D with important consequences for their survival and growth. Plants that minimize...

  8. In vitro safety assessment of the strawberry tree (Arbutus unedo L.) water leaf extract and arbutin in human peripheral blood lymphocytes.

    Science.gov (United States)

    Jurica, K; Brčić Karačonji, I; Mikolić, A; Milojković-Opsenica, D; Benković, V; Kopjar, N

    2018-04-25

    Strawberry tree (Arbutus unedo L.) leaves have long been used in the traditional medicine of the Mediterranean region. One of their most bioactive constituents is the glycoside arbutin, whose presence makes A. unedo suitable as a potential substitute for bearberry [Arctostaphylos uva ursi (L.) Spreng] leaves, an herbal preparation widely used for treating urinary tract infections. The safety and biocompatibility of strawberry tree water leaf extract have not yet been documented well. This study estimated arbutin content in strawberry tree water leaf extract (STE) using high performance liquid chromatography. Furthermore, we performed an in vitro safety assessment of the 24 h exposure to three presumably non-toxic concentrations of standardized STE and arbutin in human peripheral blood lymphocytes using the apoptosis/necrosis assay, the alkaline comet assay, and the cytokinesis-block micronucleus cytome assay. The STE was also tested for total antioxidant capacity and lipid peroxidation. At a concentration corresponding to the maximum allowable daily intake of arbutin, the tested extract was not cytotoxic, had a negligible potential for causing primary DNA damage and even hindered micronuclei formation in lymphocytes. It also showed a valuable antioxidant capacity, and did not exert marked lipid peroxidation. These promising results represent a solid frame for further development of STE-based herbal preparations. Although arbutin generally had a low DNA damaging potential, the slowing down of lymphocyte proliferation observed after 24 h of exposure points to a cytostatic effect, which merits further research.

  9. Water, gravity and trees: Relationship of tree-ring widths and total water storage dynamics

    Science.gov (United States)

    Creutzfeldt, B.; Heinrich, I.; Merz, B.; Blume, T.; Güntner, A.

    2012-04-01

    Water stored in the subsurface as groundwater or soil moisture is the main fresh water source not only for drinking water and food production but also for the natural vegetation. In a changing environment water availability becomes a critical issue in many different regions. Long-term observations of the past are needed to improve the understanding of the hydrological system and the prediction of future developments. Tree ring data have repeatedly proved to be valuable sources for reconstructing long-term climate dynamics, e.g. temperature, precipitation and different hydrological variables. In water-limited environments, tree growth is primarily influenced by total water stored in the subsurface and hence, tree-ring records usually contain information about subsurface water storage. The challenge is to retrieve the information on total water storage from tree rings, because a training dataset of water stored in the sub-surface is required for calibration against the tree-ring series. However, measuring water stored in the subsurface is notoriously difficult. We here present high-precision temporal gravimeter measurements which allow for the depth-integrated quantification of total water storage dynamics at the field scale. In this study, we evaluate the relationship of total water storage change and tree ring growth also in the context of the complex interactions of other meteorological forcing factors. A tree-ring chronology was derived from a Norway spruce stand in the Bavarian Forest, Germany. Total water storage dynamics were measured directly by the superconducting gravimeter of the Geodetic Observatory Wettzell for a 9-years period. Time series were extended to 63-years period by a hydrological model using gravity data as the only calibration constrain. Finally, water storage changes were reconstructed based on the relationship between the hydrological model and the tree-ring chronology. Measurement results indicate that tree-ring growth is primarily

  10. [Effects of soil moisture content and light intensity on the plant growth and leaf physiological characteristics of squash].

    Science.gov (United States)

    Du, She-ni; Bai, Gang-shuan; Liang, Yin-li

    2011-04-01

    A pot experiment with artificial shading was conducted to study the effects of soil moisture content and light intensity on the plant growth and leaf physiological characteristics of squash variety "Jingyingyihao". Under all test soil moisture conditions, 30% shading promoted the growth of "Jingyingyihao", with the highest yield at 70% - 80% soil relative moisture contents. 70% shading inhibited plant growth severely, only flowering and not bearing fruits, no economic yield produced. In all treatments, there was a similar water consumption trend, i. e., both the daily and the total water consumption decreased with increasing shading and decreasing soil moisture content. Among all treatments, 30% shading and 70% - 80% soil relative moisture contents had the highest water use efficiency (2.36 kg mm(-1) hm(-2)) and water output rate (1.57 kg mm(-1) hm(-2)). The net photosynthetic rate, transpiration rate, stomatal conductance, and chlorophyll content of squash leaves decreased with increasing shading, whereas the intercellular CO2 concentration was in adverse. The leaf protective enzyme activity and proline content decreased with increasing shading, and the leaf MAD content decreased in the order of 70% shading, natural radiation, and 30% shading. Under the three light intensities, the change characteristics of squash leaf photosynthesis, protective enzyme activity, and proline and MAD contents differed with the increase of soil relative moisture content.

  11. Calcium oxalate druses affect leaf optical properties in selenium-treated Fagopyrum tataricum.

    Science.gov (United States)

    Golob, Aleksandra; Stibilj, Vekoslava; Nečemer, Marijan; Kump, Peter; Kreft, Ivan; Hočevar, Anja; Gaberščik, Alenka; Germ, Mateja

    2018-03-01

    Plants of the genus Fagopyrum contain high levels of crystalline calcium oxalate (CaOx) deposits, or druses, that can affect the leaf optical properties. As selenium has been shown to modify the uptake and accumulation of metabolically important elements such as calcium, we hypothesised that the numbers of druses can be altered by selenium treatment, and this would affect the leaf optical properties. Tartary buckwheat (Fagopyrum tataricum Gaertn.) was grown outdoors in an experimental field. At the beginning of flowering, plants were foliarly sprayed with sodium selenate solution at 10 mg selenium L -1 or only with water. Plant morphological, biochemical, physiological and optical properties were examined, along with leaf elemental composition and content. Se spraying did not affect leaf biochemical and functional properties. However, it increased leaf thickness and the contents of Se in the leaves, and decreased the density of calcium oxalate druses in the leaves. Except Se content, Se spraying did not affect contents of other elements in leaves, including total calcium per dry mass of leaf tissue. Redundancy analysis showed that of all parameters tested, only the calcium oxalate druses parameters were significant in explaining the variability of the leaf reflectance and transmittance spectra. The density of CaOx druses positively correlated with the reflectance in the blue, green, yellow and UV-B regions of the spectrum, while the area of CaOx druses per mm 2 of leaf transection area positively correlated with the transmittance in the green and yellow regions of the spectrum. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Seasonal Canopy Temperatures for Normal and Okra Leaf Cotton under Variable Irrigation in the Field

    Directory of Open Access Journals (Sweden)

    James R. Mahan

    2016-11-01

    Full Text Available Temperature affects a number of physiological factors in plants and is related to water use, yield and quality in many crop species. Seasonal canopy temperature, measured with infrared thermometers, is often used in conjunction with environmental factors (e.g., air temperature, humidity, solar radiation to assess crop stress and management actions in cotton. Normal and okra leaf shapes in cotton have been associated with differences in water use and canopy temperature. The okra leaf shape in cotton is generally expected to result in lower water use and lower canopy temperatures, relative to normal leaf, under water deficits. In this study canopy temperatures were monitored in okra and normal leaf varieties for a growing season at four irrigation levels. Differences in canopy temperature (<2 °C were measured between the two leaf shapes. As irrigation levels increased, canopy temperature differences between the leaf shapes declined. At the lowest irrigation level, when differences in sensible energy exchanges due to the okra leaf shape would be enhanced, the canopy temperature of the okra leaf was warmer than the normal leaf. This suggests that varietal differences that are not related to leaf shape may have more than compensated for leaf shape differences in the canopy temperature.

  13. Thermal-based modeling of coupled carbon, water, and energy fluxes using nominal light use efficiencies constrained by leaf chlorophyll observations

    KAUST Repository

    Schull, M. A.

    2015-03-11

    Recent studies have shown that estimates of leaf chlorophyll content (Chl), defined as the combined mass of chlorophyll a and chlorophyll b per unit leaf area, can be useful for constraining estimates of canopy light use efficiency (LUE). Canopy LUE describes the amount of carbon assimilated by a vegetative canopy for a given amount of absorbed photosynthetically active radiation (APAR) and is a key parameter for modeling land-surface carbon fluxes. A carbon-enabled version of the remote-sensing-based two-source energy balance (TSEB) model simulates coupled canopy transpiration and carbon assimilation using an analytical sub-model of canopy resistance constrained by inputs of nominal LUE (βn), which is modulated within the model in response to varying conditions in light, humidity, ambient CO2 concentration, and temperature. Soil moisture constraints on water and carbon exchange are conveyed to the TSEB-LUE indirectly through thermal infrared measurements of land-surface temperature. We investigate the capability of using Chl estimates for capturing seasonal trends in the canopy βn from in situ measurements of Chl acquired in irrigated and rain-fed fields of soybean and maize near Mead, Nebraska. The results show that field-measured Chl is nonlinearly related to βn, with variability primarily related to phenological changes during early growth and senescence. Utilizing seasonally varying βn inputs based on an empirical relationship with in situ measured Chl resulted in improvements in carbon flux estimates from the TSEB model, while adjusting the partitioning of total water loss between plant transpiration and soil evaporation. The observed Chl-βn relationship provides a functional mechanism for integrating remotely sensed Chl into the TSEB model, with the potential for improved mapping of coupled carbon, water, and energy fluxes across vegetated landscapes.

  14. Antimicrobial activity of medicinal plant leaf extracts against pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Atikya Farjana

    2014-09-01

    Full Text Available Objective: To determine antibacterial activity of water, oil and methanol extracts of guava (Psidium guajava, green tea (Camellia sinensis, neem (Azadirachta indica and marigold (Calendula officinalis against different species of bacteria, Pseudomonas spp., Vibrio cholerae, Vibrio parahaemolyticus (V. parahaemolyticus, Klebsiella spp., Escherichia coli, Salmonella spp. and Staphylococcus aureus (S. aureus. Methods: Antibacterial activity of plant extracts was measured by agar well diffusion method. Results: Boiled water extracts of guava leaf showed the largest zone of inhibition (22 mm against V. parahaemolyticus. Water extracts of green tea leaf at boiling and room temperature showed 17.5 mm and 19 mm zone of inhibitions against V. parahaemolyticus and S. aureus, respectively. Boiled water extract of neem leaf showed moderate zone of inhibition against Escherichia coli (10 mm and Klebsiella spp. (11 mm. Water and oil extracts of marigold leaf at both boiling and room temperature did not show any zone of inhibition against any of the tested microorganisms. Methanol extracts of both guava and green tea leaves showed same zone of inhibition against Pseudomonus spp. (18 mm. Methanol extract of neem leaf showed antibacterial acitivity against Klebsiella spp. (16 mm and Vibrio cholerae (14 mm and that of marigold leaf showed antimicrobial activity against S. aureus (18 mm and Klebsiella spp. (12 mm. Conclusions: The results from the study suggest that the leaves of guava, green tea, neem and marigold show anibacterial activity against different bacterial species. They could be used as alternatives to common antimicrobial agents for treatment of bacterial infections.

  15. A phylogenetic approach to total evaporative water loss in mammals.

    Science.gov (United States)

    Van Sant, Matthew J; Oufiero, Christopher E; Muñoz-Garcia, Agustí; Hammond, Kimberly A; Williams, Joseph B

    2012-01-01

    Maintaining appropriate water balance is a constant challenge for terrestrial mammals, and this problem can be exacerbated in desiccating environments. It has been proposed that natural selection has provided desert-dwelling mammals physiological mechanisms to reduce rates of total evaporative water loss. In this study, we evaluated the relationship between total evaporative water loss and body mass in mammals by using a recent phylogenetic hypothesis. We compared total evaporative water loss in 80 species of arid-zone mammals to that in 56 species that inhabit mesic regions, ranging in size from 4 g to 3,500 kg, to test the hypothesis that mammals from arid environments have lower rates of total evaporative water loss than mammals from mesic environments once phylogeny is taken into account. We found that arid species had lower rates of total evaporative water loss than mesic species when using a dichotomous variable to describe habitat (arid or mesic). We also found that total evaporative water loss was negatively correlated with the average maximum and minimum environmental temperature as well as the maximum vapor pressure deficit of the environment. Annual precipitation and the variable Q (a measure of habitat aridity) were positively correlated with total evaporative water loss. These results support the hypothesis that desert-dwelling mammals have lower rates of total evaporative water loss than mesic species after controlling for body mass and evolutionary relatedness regardless of whether categorical or continuous variables are used to describe habitat.

  16. Tamarisk (Tamarix spp.) water fluxes before, during and after episodic defoliation by the saltcedar leaf beetle

    Science.gov (United States)

    Hultine, K.R.; Nagler, P.L.; Dennison, P.E.; Bush, S.E.; Ehleringer, J.R.

    2009-01-01

    Tamarisk (Tamarix) species are among the most successful and economically costly plant invaders in the western United States, in part due to its potential to remove large amounts of water from shallow aquifers. Accordingly, local, state and federal agencies have released a new biological control - the saltcedar leaf beetle (Diorhabda elongata) along many watersheds in the western United States to reduce the spread of tamarisk. The beetle defoliates tamarisk for much of the growing season resulting in potentially large seasonal declines in productivity, fitness, and water loss from tamarisk stands. We measured sap flux density (Js) using heat dissipation sensors to investigate water use patterns of tamarisk before, during and after a single, six week beetle-induced defoliation event in southeastern, Utah, USA. Granier-style probes were installed on 20 dominant trees from May through September 2008, a period that covers almost the entire growing season. As the beetle emerged from dormancy in mid-June, daytime and nighttime Js measurably increased for approximately two weeks before declining to less than 20% of predicted values (predicted by modeling Js with atmospheric vapor pressure deficit in May and June before defoliation). Tamarisk trees in mid-August produced new leaves and Js returned to pre-defoliation levels. Total Js, summed over the duration of the study was 13% lower than predicted values. These data suggest that defoliation results in only small changes in seasonal water loss from tamarisk stands. Current research is focusing on long-term ecohydrological impacts of tamarisk defoliation over multiple growing seasons.

  17. Estimation of leaf water content from far infrared (2.5-14µm) spectra using continuous wavelet analysis

    NARCIS (Netherlands)

    Ullah, S.; Skidmore, A.K.; Naeem, M.; Schlerf, M.

    2012-01-01

    The objective of this study was to estimate leaf water content based on continuous wavelet analysis from the far infrared (2.5 - 14.0 μm) spectra. The entire dataset comprised of 394 far infrared spectra which were divided into calibration (262 spectra) and validation (132 spectra) subsets. The far

  18. Soil and water warming accelerates phenology and down-regulation of leaf photosynthesis of rice plants grown under free-air CO2 enrichment (FACE).

    Science.gov (United States)

    Adachi, Minaco; Hasegawa, Toshihiro; Fukayama, Hiroshi; Tokida, Takeshi; Sakai, Hidemitsu; Matsunami, Toshinori; Nakamura, Hirofumi; Sameshima, Ryoji; Okada, Masumi

    2014-02-01

    To enable prediction of future rice production in a changing climate, we need to understand the interactive effects of temperature and elevated [CO2] (E[CO2]). We therefore examined if the effect of E[CO2] on the light-saturated leaf photosynthetic rate (Asat) was affected by soil and water temperature (NT, normal; ET, elevated) under open-field conditions at the rice free-air CO2 enrichment (FACE) facility in Shizukuishi, Japan, in 2007 and 2008. Season-long E[CO2] (+200 µmol mol(-1)) increased Asat by 26%, when averaged over two years, temperature regimes and growth stages. The effect of ET (+2°C) on Asat was not significant at active tillering and heading, but became negative and significant at mid-grain filling; Asat in E[CO2]-ET was higher than in ambient [CO2] (A[CO2])-NT by only 4%. Photosynthetic down-regulation at E[CO2] also became apparent at mid-grain filling; Asat compared at the same [CO2] in the leaf cuvette was significantly lower in plants grown in E[CO2] than in those grown in A[CO2]. The additive effects of E[CO2] and ET decreased Asat by 23% compared with that of A[CO2]-NT plants. Although total crop nitrogen (N) uptake was increased by ET, N allocation to the leaves and to Rubisco was reduced under ET and E[CO2] at mid-grain filling, which resulted in a significant decrease (32%) in the maximum rate of ribulose-1,5-bisphosphate carboxylation on a leaf area basis. Because the change in N allocation was associated with the accelerated phenology in E[CO2]-ET plants, we conclude that soil and water warming accelerates photosynthetic down-regulation at E[CO2].

  19. cassava brown streak disease effects on leaf metabolites

    African Journals Online (AJOL)

    USER

    Plate 1. Progression of CBSD in cassava leaves with scores 1= leaf from clean plant, no CBSD, 2 = Mild CBSD leaf veinal ... absorb the excess water, after which they were rolled ..... to low carbon dioxide exchange, as observed in sugar cane ...

  20. Peach water relations, gas exchange, growth and shoot mortality under water deficit in semi-arid weather conditions.

    Science.gov (United States)

    Rahmati, Mitra; Davarynejad, Gholam Hossein; Génard, Michel; Bannayan, Mohammad; Azizi, Majid; Vercambre, Gilles

    2015-01-01

    In this study the sensitivity of peach tree (Prunus persica L.) to three water stress levels from mid-pit hardening until harvest was assessed. Seasonal patterns of shoot and fruit growth, gas exchange (leaf photosynthesis, stomatal conductance and transpiration) as well as carbon (C) storage/mobilization were evaluated in relation to plant water status. A simple C balance model was also developed to investigate sink-source relationship in relation to plant water status at the tree level. The C source was estimated through the leaf area dynamics and leaf photosynthesis rate along the season. The C sink was estimated for maintenance respiration and growth of shoots and fruits. Water stress significantly reduced gas exchange, and fruit, and shoot growth, but increased fruit dry matter concentration. Growth was more affected by water deficit than photosynthesis, and shoot growth was more sensitive to water deficit than fruit growth. Reduction of shoot growth was associated with a decrease of shoot elongation, emergence, and high shoot mortality. Water scarcity affected tree C assimilation due to two interacting factors: (i) reduction in leaf photosynthesis (-23% and -50% under moderate (MS) and severe (SS) water stress compared to low (LS) stress during growth season) and (ii) reduction in total leaf area (-57% and -79% under MS and SS compared to LS at harvest). Our field data analysis suggested a Ψstem threshold of -1.5 MPa below which daily net C gain became negative, i.e. C assimilation became lower than C needed for respiration and growth. Negative C balance under MS and SS associated with decline of trunk carbohydrate reserves--may have led to drought-induced vegetative mortality.

  1. Biophysical control of leaf temperature

    Science.gov (United States)

    Dong, N.; Prentice, I. C.; Wright, I. J.

    2014-12-01

    In principle sunlit leaves can maintain their temperatures within a narrower range than ambient temperatures. This is an important and long-known (but now overlooked) prediction of energy balance theory. Net radiation at leaf surface in steady state (which is reached rapidly) must be equal to the combination of sensible and latent heat exchanges with surrounding air, the former being proportional to leaf-to-air temperature difference (ΔT), the latter to the transpiration rate. We present field measurements of ΔT which confirm the existence of a 'crossover temperature' in the 25-30˚C range for species in a tropical savanna and a tropical rainforest environment. This finding is consistent with a simple representation of transpiration as a function of net radiation and temperature (Priestley-Taylor relationship) assuming an entrainment factor (ω) somewhat greater than the canonical value of 0.26. The fact that leaves in tropical forests are typically cooler than surrounding air, often already by solar noon, is consistent with a recently published comparison of MODIS day-time land-surface temperatures with air temperatures. Theory further predicts a strong dependence of leaf size (which is inversely related to leaf boundary-layer conductance, and therefore to absolute magnitude of ΔT) on moisture availability. Theoretically, leaf size should be determined by either night-time constraints (risk of frost damage to active leaves) or day-time constraints (risk of heat stress damage),with the former likely to predominate - thereby restricting the occurrence of large leaves - at high latitudes. In low latitudes, daytime maximum leaf size is predicted to increase with temperature, provided that water is plentiful. If water is restricted, however, transpiration cannot proceed at the Priestley-Taylor rate, and it quickly becomes advantageous for plants to have small leaves, which do not heat up much above the temperature of their surroundings. The difference between leaf

  2. BOREAS TE-9 NSA Leaf Chlorophyll Density

    Science.gov (United States)

    Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Margolis, Hank; Sy, Mikailou

    2000-01-01

    The BOREAS TE-9 team collected several data sets related to chemical and photosynthetic properties of leaves in boreal forest tree species. These data were collected to help provide an explanation of potential seasonal and spatial changes of leaf pigment properties in boreal forest species at the NSA. At different dates (FFC-Winter, FFC-Thaw, IFC-1, IFC-2, and IMC-3), foliage samples were collected from the upper third of the canopy for five NSA sites (YJP, OJP, OBS, UBS, and OA) near Thompson, Manitoba. Subsamples of 100 needles for black spruce, 20 needles for jack pine, and single leaf for trembling aspen were cut into pieces and immersed in a 20-mL DMF aliquot in a Nalgene test tube. The extracted foliage materials were then oven-dried at 68 C for 48 hours and weighed. Extracted leaf dry weight was converted to a total leaf area basis to express the chlorophyll content in mg/sq cm of total leaf area. The data are provided in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  3. Rapid, high-resolution measurement of leaf area and leaf orientation using terrestrial LiDAR scanning data

    International Nuclear Information System (INIS)

    Bailey, Brian N; Mahaffee, Walter F

    2017-01-01

    The rapid evolution of high performance computing technology has allowed for the development of extremely detailed models of the urban and natural environment. Although models can now represent sub-meter-scale variability in environmental geometry, model users are often unable to specify the geometry of real domains at this scale given available measurements. An emerging technology in this field has been the use of terrestrial LiDAR scanning data to rapidly measure the three-dimensional geometry of trees, such as the distribution of leaf area. However, current LiDAR methods suffer from the limitation that they require detailed knowledge of leaf orientation in order to translate projected leaf area into actual leaf area. Common methods for measuring leaf orientation are often tedious or inaccurate, which places constraints on the LiDAR measurement technique. This work presents a new method to simultaneously measure leaf orientation and leaf area within an arbitrarily defined volume using terrestrial LiDAR data. The novelty of the method lies in the direct measurement of the fraction of projected leaf area G from the LiDAR data which is required to relate projected leaf area to total leaf area, and in the new way in which radiation transfer theory is used to calculate leaf area from the LiDAR data. The method was validated by comparing LiDAR-measured leaf area to (1) ‘synthetic’ or computer-generated LiDAR data where the exact area was known, and (2) direct measurements of leaf area in the field using destructive sampling. Overall, agreement between the LiDAR and reference measurements was very good, showing a normalized root-mean-squared-error of about 15% for the synthetic tests, and 13% in the field. (paper)

  4. Leaf-jams - A new and unique leaf deposit in the ephemeral Hoanib River, NW Namibia: Origin and plant taphonomic implications

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Christa-Ch. [University of Vienna, Department of Palaeontology, Palaeobotany Studies Group, Althanstrasse 14, 1090, Vienna (Austria); Rice, A. Hugh N. [University of Vienna, Department of Geodynamics and Sedimentology, Althanstrasse 14, 1090, Vienna (Austria)

    2010-08-01

    This paper documents a previously unrecorded type of leaf deposit, comprising essentially monospecific linear accumulations of Colophospermum mopane leaves on a point bar of the ephemeral Hoanib River, NW Namibia. In these 'leaf-jams', leaf laminae stand on edge, orientated more-or-less normal to bedding. Leaf-jams, which formed upstream of cobbles, clumps of grass and sticks wedged against the former two, were orientated subparallel to the adjacent meandering river-bed, such that over the 40 m of their occurrence, their mean azimuth changed by 59 anticlockwise downstream. The longest leaf-jam was 50 cm and contained approximately 500 leaves, as well as grass culms, twigs (C. mopane, Tamarix usneoides and unidentified) and medium- to fine-grained sand and silt. Individual leaf-jams were partially buried in the point bar sediments up to a depth of 3 cm. Leaf-jam formation occurred in the austral summer of 2006, during the waning stage of a major flood caused by anomalous tropical to extra-tropical storms. Their monospecifity is due to the overwhelming preponderance of the zonal taxon C. mopane in the catchment area, although the Khowarib Gorge contains a quite diverse azonal plant association due to the presence of a permanent water-seep. During leaf-jam formation, the water depth was less than the height of the cobbles (0.1 m), with stream flow-rates competent to transport medium-grained sand (velocity estimated at 0.5 m s{sup -} {sup 1}). Leaves must have been partially or fully waterlogged to inhibit buoyancy forces tending to lift them out of the developing leaf-jams, which propagated upstream in a manner comparable to longitudinal bars in a braided river. If fossilised, such deposits would probably lead to a very biased interpretation of the composition of the surrounding flora; the correct interpretation would be the one least favoured by palaeobotanists. (author)

  5. Potencial de água no solo e na folha da videira "Sugraone" sob déficit hídrico Soil and leaf water potential of "Sugraone" grape under water deficit

    Directory of Open Access Journals (Sweden)

    Lígia B. Marinho

    2011-11-01

    Full Text Available Propôs-se com este estudo conhecer a variação do potencial da água no solo e na folha da videira "Superior Seedless", tal como o crescimento da baga da uva sob diferentes condições de irrigação na fase de maturação da uva, na Fazenda Agrobrás Tropical do Brasil S/A, em Casa Nova, BA, em outubro de 2007. A videira foi irrigada nas épocas 21, 13 e 5 dias antes da colheita, com lâminas de 100, 50 e 0% da evapotranspiração da cultura e um tratamento adicional ("manejo do produtor". O potencial da água na folha e no solo foi aferido com a câmara de pressão e tensiômetros, respectivamente. O potencial da água da folha variou de -0,95 a -1,80 MPa, ao meio- dia e de -0,10 a -0,27 MPa, ao alvorecer. O potencial mátrico da água do solo atingiu valores de -5 a -79,5 kPa para os tratamentos menos e mais deficitários. O potencial da água na folha ao meio-dia sugere que, em alguns dias, o parreiral se encontrava sob estresse moderado e, em outros, sob estresse severo, independendo dos tratamentos de déficit hídrico. Ao alvorecer, o potencial indicou que as videiras estavam sob estresse suave ou em condições adequadas de manejo de água, mesmo a potencial matricial do solo elevado, em que não houve redução significativa no crescimento das bagas das uvas.This study aimed to measure the variation of soil and leaf water potential in the Sugraone (Superior Seedless grape, as well as the berry growth, under different irrigation conditions in the Fazenda Agrobrás Tropical do Brazil S/A, in Casa Nova, BA, in October, 2007 during maturation stage. The Superior Seedless cultivar was irrigated at 21, 13 e 5 days before harvest with water depths of 100, 50 e 0% of crop evapotranspiration (ETc and an additional treatment consisting of the farmer management. The results of leaf water potential using a pressure chamber and the respective soil matric potential from tensiometric readings are shown. Measurements of leaf water potential reached

  6. Inferring foliar water uptake using stable isotopes of water.

    Science.gov (United States)

    Goldsmith, Gregory R; Lehmann, Marco M; Cernusak, Lucas A; Arend, Matthias; Siegwolf, Rolf T W

    2017-08-01

    A growing number of studies have described the direct absorption of water into leaves, a phenomenon known as foliar water uptake. The resultant increase in the amount of water in the leaf can be important for plant function. Exposing leaves to isotopically enriched or depleted water sources has become a common method for establishing whether or not a plant is capable of carrying out foliar water uptake. However, a careful inspection of our understanding of the fluxes of water isotopes between leaves and the atmosphere under high humidity conditions shows that there can clearly be isotopic exchange between the two pools even in the absence of a change in the mass of water in the leaf. We provide experimental evidence that while leaf water isotope ratios may change following exposure to a fog event using water with a depleted oxygen isotope ratio, leaf mass only changes when leaves are experiencing a water deficit that creates a driving gradient for the uptake of water by the leaf. Studies that rely on stable isotopes of water as a means of studying plant water use, particularly with respect to foliar water uptake, must consider the effects of these isotopic exchange processes.

  7. Leaf Composition of American Bur-Reed (Sparganium americanum Nutt.) to Determine Pesticide Mitigation Capability.

    Science.gov (United States)

    Alsharekh, Anfal; Swatzell, Lucinda J; Moore, Matthew T

    2018-04-01

    American bur-reed (Sparganium americanum Nutt.), a common aquatic plant in the middle and eastern United States and Canada, is often located in water-retaining drainage areas. The purpose of this study was to determine the leaf composition of S. americanum, paying attention to the cuticular waxes and the epidermis, and its ability to sorb pesticides. S. americanum leaves (n = 100) were collected in both early (June) and late (August) summer. Transverse sections of S. americanum were stained and studied with brightfield and fluorescence microscopy to estimate the structural and chemical nature of the leaf tissues cross sections. Mean total lipid content in early summer leaf samples (1.47 ± 0.83 mg mL -1 ) was significantly greater (alpha 0.05) than late summer leaves (0.15 ± 0.36 mg mL -1 ). In vitro analysis of epidermal peel permeability exposed to atrazine and malathion determined little to no sorption by the plant. Therefore, the structure of S. americanum leaves suggest this species does not have the capacity of sorbing these pesticides from runoff water.

  8. Stomatal clustering in Begonia associates with the kinetics of leaf gaseous exchange and influences water use efficiency.

    Science.gov (United States)

    Papanatsiou, Maria; Amtmann, Anna; Blatt, Michael R

    2017-04-01

    Stomata are microscopic pores formed by specialized cells in the leaf epidermis and permit gaseous exchange between the interior of the leaf and the atmosphere. Stomata in most plants are separated by at least one epidermal pavement cell and, individually, overlay a single substomatal cavity within the leaf. This spacing is thought to enhance stomatal function. Yet, there are several genera naturally exhibiting stomata in clusters and therefore deviating from the one-cell spacing rule with multiple stomata overlaying a single substomatal cavity. We made use of two Begonia species to investigate whether clustering of stomata alters guard cell dynamics and gas exchange under different light and dark treatments. Begonia plebeja, which forms stomatal clusters, exhibited enhanced kinetics of stomatal conductance and CO2 assimilation upon light stimuli that in turn were translated into greater water use efficiency. Our findings emphasize the importance of spacing in stomatal clusters for gaseous exchange and plant performance under environmentally limited conditions. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  9. Genotype differences in 13C discrimination between atmosphere and leaf matter match differences in transpiration efficiency at leaf and whole-plant levels in hybrid Populus deltoides x nigra.

    Science.gov (United States)

    Rasheed, Fahad; Dreyer, Erwin; Richard, Béatrice; Brignolas, Franck; Montpied, Pierre; Le Thiec, Didier

    2013-01-01

    (13) C discrimination between atmosphere and bulk leaf matter (Δ(13) C(lb) ) is frequently used as a proxy for transpiration efficiency (TE). Nevertheless, its relevance is challenged due to: (1) potential deviations from the theoretical discrimination model, and (2) complex time integration and upscaling from leaf to whole plant. Six hybrid genotypes of Populus deltoides×nigra genotypes were grown in climate chambers and tested for whole-plant TE (i.e. accumulated biomass/water transpired). Net CO(2) assimilation rates (A) and stomatal conductance (g(s) ) were recorded in parallel to: (1) (13) C in leaf bulk material (δ(13) C(lb) ) and in soluble sugars (δ(13) C(ss) ) and (2) (18) O in leaf water and bulk leaf material. Genotypic means of δ(13) C(lb) and δ(13) C(ss) were tightly correlated. Discrimination between atmosphere and soluble sugars was correlated with daily intrinsic TE at leaf level (daily mean A/g(s) ), and with whole-plant TE. Finally, g(s) was positively correlated to (18) O enrichment of bulk matter or water of leaves at individual level, but not at genotype level. We conclude that Δ(13) C(lb) captures efficiently the genetic variability of whole-plant TE in poplar. Nevertheless, scaling from leaf level to whole-plant TE requires to take into account water losses and respiration independent of photosynthesis, which remain poorly documented. © 2012 Blackwell Publishing Ltd.

  10. Extraction Optimization and Antioxidant Properties of African Eggplant (Solanum macrocarpon Leaf Polyphenols

    Directory of Open Access Journals (Sweden)

    A. A. Famuwagun

    2017-01-01

    Full Text Available Optimization of the yield, total phenolic content (TPC, and total antioxidant activities (TAA of polyphenol concentrates extracted from Solanum macrocarpon leaves was studied using response surface methodology. The process variables investigated included extraction temperature (30, 50, and 70°C, extraction time (2, 4, and 6 h, and dried leaf powder : water ratio (1 : 10, 1 : 20, and 1 : 30 w/v. Box–Behnken design resulted in 15 experimental runs. The results showed the following optimum extraction conditions: temperature, 49.05°C; extraction time, 243 min; leaf powder : water ratio, 1 : 22 w/v. The optimized extraction conditions gave polyphenol concentrate yield, TPC, and TAA values of 24.94%, 421.09 mg GAE/g, and 23.81 mg AAE/g, respectively. Results of the in vitro antioxidant activities of the polyphenol concentrate showed 2, 2-diphenyl-2-picrylhydrazyl hydrate, metal chelating ability, and ferric reducing ability values of 76.78%, 80.22%, and 56.46 mg AAE/g, respectively. The study concludes that the experimental values compared closely with the predicted values, which indicates suitability of the model employed for polyphenol extraction optimization from dried S. macrocarpon leaves.

  11. Measurement of leaf hydraulic conductance and stomatal conductance and their responses to irradiance and dehydration using the Evaporative Flux Method (EFM).

    Science.gov (United States)

    Sack, Lawren; Scoffoni, Christine

    2012-12-31

    Water is a key resource, and the plant water transport system sets limits on maximum growth and drought tolerance. When plants open their stomata to achieve a high stomatal conductance (gs) to capture CO2 for photosynthesis, water is lost by transpiration(1,2). Water evaporating from the airspaces is replaced from cell walls, in turn drawing water from the xylem of leaf veins, in turn drawing from xylem in the stems and roots. As water is pulled through the system, it experiences hydraulic resistance, creating tension throughout the system and a low leaf water potential (Ψ(leaf)). The leaf itself is a critical bottleneck in the whole plant system, accounting for on average 30% of the plant hydraulic resistance(3). Leaf hydraulic conductance (K(leaf) = 1/ leaf hydraulic resistance) is the ratio of the water flow rate to the water potential gradient across the leaf, and summarizes the behavior of a complex system: water moves through the petiole and through several orders of veins, exits into the bundle sheath and passes through or around mesophyll cells before evaporating into the airspace and being transpired from the stomata. K(leaf) is of strong interest as an important physiological trait to compare species, quantifying the effectiveness of the leaf structure and physiology for water transport, and a key variable to investigate for its relationship to variation in structure (e.g., in leaf venation architecture) and its impacts on photosynthetic gas exchange. Further, K(leaf) responds strongly to the internal and external leaf environment(3). K(leaf) can increase dramatically with irradiance apparently due to changes in the expression and activation of aquaporins, the proteins involved in water transport through membranes(4), and K(leaf) declines strongly during drought, due to cavitation and/or collapse of xylem conduits, and/or loss of permeability in the extra-xylem tissues due to mesophyll and bundle sheath cell shrinkage or aquaporin deactivation(5

  12. Optimal ship forms for minimum total resistance in shallow water

    OpenAIRE

    Zhao, Lian-en

    1984-01-01

    Optimal ship forms for minimum total resistance in shallow water Optimal ship forms for minimum total resistance in shallow water: An attempt is made to obtain shallow-water optimal ship forms for total resistance by means of "tent" function representation under the constraints that the main dimensions of the ship and the water-line area were kept constant. The objective function in the quadratic programming is the sum of wave-making resistance calculated by Sretenski's formula and viscou...

  13. Leaf d15N as a physiological indicator of the responsiveness of N2-fixing alfalfa plants to elevated [CO2], temperature and low water availability

    Directory of Open Access Journals (Sweden)

    Idoia eAriz

    2015-08-01

    Full Text Available The natural 15N/14N isotope composition (δ15N of a tissue is a consequence of its N source and N physiological mechanisms in response to the environment. It could potentially be used as a tracer of N metabolism in plants under changing environmental conditions, where primary N metabolism may be complex, and losses and gains of N fluctuate over time. In order to test the utility of δ15N as an indicator of plant N status in N2-fixing plants grown under various environmental conditions, alfalfa (Medicago sativa L. plants were subjected to distinct conditions of [CO2] (400 versus 700 mol mol-1, temperature (ambient versus ambient + 4ºC and water availability (fully watered versus water deficiency - WD. As expected, increased [CO2] and temperature stimulated photosynthetic rates and plant growth, whereas these parameters were negatively affected by WD. The determination of δ15N in leaves, stems, roots and nodules showed that leaves were the most representative organs of the plant response to increased [CO2] and WD. Depletion of heavier N isotopes in plants grown under higher [CO2] and WD conditions reflected decreased transpiration rates, but could also be related to a higher N demand in leaves, as suggested by the decreased leaf N and total soluble protein (TSP contents detected at 700 mol mol-1 [CO2] and WD conditions. In summary, leaf δ15N provides relevant information integrating parameters which condition plant responsiveness (e.g. photosynthesis, TSP, N demand and water transpiration to environmental conditions.

  14. Physical properties of snacks made from cassava leaf flour

    Directory of Open Access Journals (Sweden)

    Adriana Cristina Ferrari

    2014-02-01

    Full Text Available The food industry is continually growing with new products becoming available every year. Extrusion combines a number of unit operations in one energy efficient rapid continuous process and can be used to produce a wide variety of snacks foods. The objective of this study was to evaluate the effect of extrusion temperature, screw speed, and amount of cassava leaf flour mixed with cassava starch on the physical properties of extruded snacks processed using a single screw extruder. A central composite rotational design, including three factors with 20 treatments, was used in the experimental design. Dependent variables included the expansion index, specific volume, color, water absorption index, and water solubility index. Among the parameters examined, the amount of cassava leaf flour and extrusion temperature showed significant effects on extruded snack characteristics. Mixtures containing 10% of cassava leaf flour extruded at 100°C and 255 rpm shows favorable levels of expansion, color, water absorption index, and water solubility index.

  15. Total alkaloid content in various fractions of Tabernaemonata sphaerocarpa Bl. (Jembirit) leaves

    Science.gov (United States)

    Salamah, N.; Ningsih, D. S.

    2017-11-01

    Tabernaemontana sphaerocarpa Bl. (Jembirit) is one of the Apocynaceae family plants containing alkaloid compound. Traditionally, it is used as an anti-inflammatory medicine. It is found to have a new bisindole alkaloid compound that shows a potent cytotoxic activity in human cancer. This study aimed to know the total alkaloid content in some fractions of ethanolic extract of T. sphaerocarpa Bl. leaf powder was extracted by maceration method in 70% ethanol solvent. Then, the extract was fractionated in a separatory funnel using water, ethyl acetate, and hexane. The total alkaloid content in each fraction was analyzed with visible spectrophotometric methods based on the reaction with Bromocresol Green (BCG). The total alkaloids in water fraction and ethyl acetate fraction were (0.0312±0.0009)% and (0.0281±0.0014)%, respectively. Meanwhile, the total alkaloid content in hexane was not detected. The statistical analysis, performed in SPSS, resulted in a significant difference between the total alkaloids in water fraction and ethyl acetate fraction. The total alkaloid in water fraction of T. sphaerocarpa Bl. was higher than the one in ethyl acetate fraction.

  16. Effects of Water Solutions on Extracting Green Tea Leaves

    Directory of Open Access Journals (Sweden)

    Wen-Ying Huang

    2013-01-01

    Full Text Available This study investigates the effects of water solutions on the antioxidant content of green tea leaf extracts. Green teas prepared with tap water and distilled water were compared with respect to four antioxidant assays: total phenol content, reducing power, DMPD assay, and trolox equivalent antioxidant capacity assay. The results indicate that green tea prepared with distilled water exhibits higher antioxidant activity than that made with tap water. The high performance liquid chromatography showed that major constituents of green tea were found in higher concentrations in tea made with distilled water than in that made with tap water. This could be due to less calcium fixation in leaves and small water clusters. Water solutions composed of less mineralisation are more effective in promoting the quality of green tea leaf extracts.

  17. MALDI-MS Imaging Analysis of Fungicide Residue Distributions on Wheat Leaf Surfaces.

    Science.gov (United States)

    Annangudi, Suresh P; Myung, Kyung; Avila Adame, Cruz; Gilbert, Jeffrey R

    2015-05-05

    Improved retention and distribution of agrochemicals on plant surfaces is an important attribute in the biological activity of pesticide. Although retention of agrochemicals on plants after spray application can be quantified using traditional analytical techniques including LC or GC, the spatial distribution of agrochemicals on the plants surfaces has received little attention. Matrix assisted laser desorption/ionization (MALDI) imaging technology has been widely used to determine the distribution of proteins, peptides and metabolites in different tissue sections, but its application to environmental research has been limited. Herein, we probed the potential utility of MALDI imaging in characterizing the distribution of three commercial fungicides on wheat leaf surfaces. Using this MALDI imaging method, we were able to detect 500 ng of epoxiconazole, azoxystrobin, and pyraclostrobin applied in 1 μL drop on the leaf surfaces using MALDI-MS. Subsequent dilutions of pyraclostrobin revealed that the compound can be chemically imaged on the leaf surfaces at levels as low as 60 ng of total applied in the area of 1 μL droplet. After application of epoxiconazole, azoxystrobin, and pyraclostrobin at a field rate of 100 gai/ha in 200 L water using a track sprayer system, residues of these fungicides on the leaf surfaces were sufficiently visualized. These results suggest that MALDI imaging can be used to monitor spatial distribution of agrochemicals on leaf samples after pesticide application.

  18. Frost and leaf-size gradients in forests: global patterns and experimental evidence.

    Science.gov (United States)

    Lusk, Christopher H; Clearwater, Michael J; Laughlin, Daniel C; Harrison, Sandy P; Prentice, Iain Colin; Nordenstahl, Marisa; Smith, Benjamin

    2018-05-16

    Explanations of leaf size variation commonly focus on water availability, yet leaf size also varies with latitude and elevation in environments where water is not strongly limiting. We provide the first conclusive test of a prediction of leaf energy balance theory that may explain this pattern: large leaves are more vulnerable to night-time chilling, because their thick boundary layers impede convective exchange with the surrounding air. Seedlings of 15 New Zealand evergreens spanning 12-fold variation in leaf width were exposed to clear night skies, and leaf temperatures were measured with thermocouples. We then used a global dataset to assess several climate variables as predictors of leaf size in forest assemblages. Leaf minus air temperature was strongly correlated with leaf width, ranging from -0.9 to -3.2°C in the smallest- and largest-leaved species, respectively. Mean annual temperature and frost-free period were good predictors of evergreen angiosperm leaf size in forest assemblages, but no climate variable predicted deciduous leaf size. Although winter deciduousness makes large leaves possible in strongly seasonal climates, large-leaved evergreens are largely confined to frost-free climates because of their susceptibility to radiative cooling. Evergreen leaf size data can therefore be used to enhance vegetation models, and to infer palaeotemperatures from fossil leaf assemblages. © 2018 The Authors New Phytologist © 2018 New Phytologist Trust.

  19. On the global relationships between photosynthetic water-use efficiency, leaf mass per unit area and atmospheric demand in woody and herbaceous plants

    Science.gov (United States)

    Letts, M. G.; Fox, T. A.; Gulias, J.; Galmes, J.; Hikosaka, K.; Wright, I.; Flexas, J.; Awada, T.; Rodriguez-Calcerrada, J.; Tobita, H.

    2013-12-01

    A global dataset was compiled including woody and herbaceous C3 species from forest, Mediterranean and grassland-shrubland ecosystems, to elucidate the dependency of photosynthetic water-use efficiency on vapour pressure deficit (D) and leaf traits. Mean leaf mass per unit area (LMA) was lower and mass-based leaf nitrogen content (Nmass) was higher in herbaceous species. Higher mean stomatal conductance (gs), transpiration rate (E) and net CO2 assimilation rate under light saturating conditions (Amax) were observed in herbs, but photosynthetic and intrinsic water-use efficiencies (WUE = Amax/E and WUEi = Amax/gs) were lower than in woody plants. Woody species maintained stricter stomatal regulation of water loss at low D, resulting in a steeper positive and linear relationship between log D and log E. Herbaceous species possessed very high gs at low D, resulting in higher ratio of substomatal to atmospheric CO2 concentrations (ci/ca) and E, but lower WUE and WUEi than woody plants, despite higher Amax. The lower WUE and higher rates of gas exchange were most pronounced in herbs with low LMA and high Nmass. Photosynthetic water use also differed between species from grassland-shrubland and Mediterranean or forest environments. Water-use efficiency showed no relationship with either D or LMA in grassland-shrubland species, but showed a negative relationship with D in forest and chaparral. The distinct photosynthetic water-use of woody and herbaceous plants is consistent with the opportunistic growth strategy of herbs and the more conservative growth strategy of woody species. Further research is recommended to examine the implications of these functional group and ecosystem differences in the contexts of climate and atmospheric change.

  20. Biophysical constraints on leaf expansion in a tall conifer.

    Science.gov (United States)

    Fredrick C. Meinzer; Barbara J. Bond; Jennifer A. Karanian

    2008-01-01

    The physiological mechanisms responsible for reduced extension growth as trees increase in height remain elusive. We evaluated biophysical constraints on leaf expansion in old-growth Douglas-fir (Psuedotsuga menziesii (Mirb.) Franco) trees. Needle elongation rates, plastic and elastic extensibility, bulk leaf water, (L...

  1. Leaf nutrient resorption, leaf lifespan and the retention of nutrients in seagrass systems

    NARCIS (Netherlands)

    Hemminga, M.A.; Marbà, N.; Stapel, J.

    1999-01-01

    Efficient nutrient resorption from senescing leaves, and extended leaf life spans are important strategies in order to conserve nutrients for plants in general. Despite the fact that seagrasses often grow in oligotrophic waters, these conservation strategies are not strongly developed in seagrasses.

  2. Effect of the extraction solvent on the oleuropein content and antioxidant properties of olive leaf (cv. Oblica, Lastovka and Levantinka extracts

    Directory of Open Access Journals (Sweden)

    M. Gotovac

    2014-01-01

    Full Text Available In the last few decades numerous studies have proved that an olive leaf is a rich source of bioactive phenolic compounds, mainly oleuropein and its derivatives. The aim of this study was to investigate the influence of the extraction solvent on the phenolic and oleuropein content in the leaf extracts of Dalmatian autochthonic olive cultivars: Oblica, Lastovka and Levantinka. The antioxidant activity of leaf extracts was determined using FRAP method and by metal chelating activity evaluation. The recovery obtained using methanol and ethanol (50:50, v/v was higher than by use of water solvents. The highest share of total phenols and oleuropein was detected in ethanolic extract of Lastovka, while almost two-fold lower amounts were obtained using water extracts, both hot water and room temperature water. The extremely significant correlation between the FRAP and oleuropein/phenolic content points out the importance of these compounds in the total reducing activity of the extracts. All tested extracts provided good chelating activity probably due to the high concentrations of oleuropein but also the presence of other compounds with catechol structure, which is the most important structural feature of strong chelating activity. According to the obtained results it can be concluded that the extraction of polyphenols from olive leaves, especially from Lastovka cultivar, could present an interesting means of increasing the value of this cheap plant material that often remains unused after the harvest.

  3. The narrow-leaf syndrome: a functional and evolutionary approach to the form of fog-harvesting rosette plants.

    Science.gov (United States)

    Martorell, Carlos; Ezcurra, Exequiel

    2007-04-01

    Plants that use fog as an important water-source frequently have a rosette growth habit. The performance of this morphology in relation to fog interception has not been studied. Some first-principles from physics predict that narrow leaves, together with other ancillary traits (large number and high flexibility of leaves, caudices, and/or epiphytism) which constitute the "narrow-leaf syndrome" should increase fog-interception efficiency. This was tested using aluminum models of rosettes that differed in leaf length, width and number and were exposed to artificial fog. The results were validated using seven species of Tillandsia and four species of xerophytic rosettes. The total amount of fog intercepted in rosette plants increased with total leaf area, while narrow leaves maximized interception efficiency (measured as interception per unit area). The number of leaves in the rosettes is physically constrained because wide-leafed plants can only have a few blades. At the limits of this constraint, net fog interception was independent of leaf form, but interception efficiency was maximized by large numbers of narrow leaves. Atmospheric Tillandsia species show the narrow-leaf syndrome. Their fog interception efficiencies were correlated to the ones predicted from aluminum-model data. In the larger xerophytic rosette species, the interception efficiency was greatest in plants showing the narrow-leaf syndrome. The adaptation to fog-harvesting in several narrow-leaved rosettes was tested for evolutionary convergence in 30 xerophytic rosette species using a comparative method. There was a significant evolutionary tendency towards the development of the narrow-leaf syndrome the closer the species grew to areas where fog is frequently available. This study establishes convergence in a very wide group of plants encompassing genera as contrasting as Tillandsia and Agave as a result of their dependence on fog.

  4. Remote Sensing of Vegetation Nitrogen Content for Spatially Explicit Carbon and Water Cycle Estimation

    Science.gov (United States)

    Zhang, Y. L.; Miller, J. R.; Chen, J. M.

    2009-05-01

    Foliage nitrogen concentration is a determinant of photosynthetic capacity of leaves, thereby an important input to ecological models for estimating terrestrial carbon and water budgets. Recently, spectrally continuous airborne hyperspectral remote sensing imagery has proven to be useful for retrieving an important related parameter, total chlorophyll content at both leaf and canopy scales. Thus remote sensing of vegetation biochemical parameters has promising potential for improving the prediction of global carbon and water balance patterns. In this research, we explored the feasibility of estimating leaf nitrogen content using hyperspectral remote sensing data for spatially explicit estimation of carbon and water budgets. Multi-year measurements of leaf biochemical contents of seven major boreal forest species were carried out in northeastern Ontario, Canada. The variation of leaf chlorophyll and nitrogen content in response to various growth conditions, and the relationship between them,were investigated. Despite differences in plant type (deciduous and evergreen), leaf age, stand growth conditions and developmental stages, leaf nitrogen content was strongly correlated with leaf chlorophyll content on a mass basis during the active growing season (r2=0.78). With this general correlation, leaf nitrogen content was estimated from leaf chlorophyll content at an accuracy of RMSE=2.2 mg/g, equivalent to 20.5% of the average measured leaf nitrogen content. Based on this correlation and a hyperspectral remote sensing algorithm for leaf chlorophyll content retrieval, the spatial variation of leaf nitrogen content was inferred from the airborne hyperspectral remote sensing imagery acquired by Compact Airborne Spectrographic Imager (CASI). A process-based ecological model Boreal Ecosystem Productivity Simulator (BEPS) was used for estimating terrestrial carbon and water budgets. In contrast to the scenario with leaf nitrogen content assigned as a constant value without

  5. A meta-analysis of leaf gas exchange and water status responses to drought.

    Science.gov (United States)

    Yan, Weiming; Zhong, Yangquanwei; Shangguan, Zhouping

    2016-02-12

    Drought is considered to be one of the most devastating natural hazards, and it is predicted to become increasingly frequent and severe in the future. Understanding the plant gas exchange and water status response to drought is very important with regard to future climate change. We conducted a meta-analysis based on studies of plants worldwide and aimed to determine the changes in gas exchange and water status under different drought intensities (mild, moderate and severe), different photosynthetic pathways (C3 and C4) and growth forms (herbs, shrubs, trees and lianas). Our results were as follows: 1) drought negatively impacted gas exchange and water status, and stomatal conductance (gs) decreased more than other physiological traits and declined to the greatest extent in shrubs and C3 plants. Furthermore, C4 plants had an advantage compared to C3 plants under the same drought conditions. 2) The decrease in gs mainly reduced the transpiration rate (Tr), and gs could explain 55% of the decrease in the photosynthesis (A) and 74% of the decline in Tr. 3). Finally, gas exchange showed a close relationship with the leaf water status. Our study provides comprehensive information about the changes in plant gas exchange and water status under drought.

  6. Distribution of leaf characteristics in relation to orientation within the canopy of woody species

    Science.gov (United States)

    Escudero, Alfonso; Fernández, José; Cordero, Angel; Mediavilla, Sonia

    2013-04-01

    Over the last few decades considerable effort has been devoted to research of leaf adaptations to environmental conditions. Many studies have reported strong differences in leaf mass per unit area (LMA) within a single tree depending on the photosynthetic photon flux density (PPFD) incident on different locations in the crown. There are fewer studies, however, of the effects of differences in the timing of light incidence during the day on different crown orientations. Leaves from isolated trees of Quercus suber and Quercus ilex in a cold Mediterranean climate were sampled to analyze differences in LMA and other leaf traits among different crown orientations. Gas-exchange rates, leaf water potentials, leaf temperatures and PPFD incident on leaf surfaces in different crown orientations were also measured throughout one entire summer day for each species. Mean daily PPFD values were similar for the leaves from the eastern and western sides of the canopy. On the western side, PPFD reached maximum values during the afternoon. Maximum leaf temperatures were approximately 10-20% higher on the west side, whereas minimum leaf water potentials were between 10 and 24% higher on the east side. Maximum transpiration rates were approximately 22% greater on the west, because of the greater leaf-to-air vapor pressure deficits (LAVPD). Mean individual leaf area was around 10% larger on the east than on the west side of the trees. In contrast, there were no significant differences in LMA between east and west sides of the crown. Contrary to our expectations, more severe water stress on the west side did not result in increases in LMA, although it was associated with lower individual leaf area. We conclude that increases in LMA measured by other authors along gradients of water stress would be due to differences in light intensity between dry and humid sites.

  7. Nutritive Value of Fermented Water Hyacinth (Eichornia crassipes Leaf with Aspergillus niger in Tegal Duck

    Directory of Open Access Journals (Sweden)

    I Mangisah

    2010-05-01

    Full Text Available Two steps of experiment were conducted to evaluate the proximate composition and nutritive value of fermented water hyacinth leaf (WHL with Aspergillus niger in Tegal duck. Twenty two heads of eight-week Tegal ducks with an average body weight of 1202.55 + 111.14 g were used in this experiment. There were two treatments namely: non-fermented (NFWH and fermented with Aspergillus niger (FWHAN. Each treatment was replicated 10 times. Data gathered were analyzed using t-student test. The proximate composition between NFWH and FWHAN showed an increase in crude protein/CP (11.44 vs 16.09% and ash (12.76 vs 22.37% but a decrease in crude fiber/CF (21.51 vs 16.62% and nitrogen free extract/NFE (53.20 vs 43.59%. The nutritive value of diet for eight-week Tegal ducks showed that fermentation of WHL with Aspergillus niger significantly increased CP digestibility, true metabolizable energy (TME and nitrogen retention (NR, but not for CF digestibility. It could be concluded that fermentation of WHL with Aspergillus niger increases the nutrient quality and the nutritive value of diet for eight-week Tegal ducks in term of CP digestibility, TME and NR. (Animal Production 12(2: 100-104 (2010Key Words: water hyacinth leaf, fermentation, Aspergillus niger, biological value, Tegal ducks

  8. Infrared remote sensing for canopy temperature in paddy field and relationship between leaf temperature and leaf color

    International Nuclear Information System (INIS)

    Wakiyama, Y.

    2002-01-01

    Infrared remote sensing is used for crop monitoring, for example evaluation of water stress, detection of infected crops and estimation of transpiration and photosynthetic rates. This study was conducted to show another application of remote sensing information. The relationship between rice leaf temperature and chlorophyll content in the leaf blade was investigated by using thermography during the ripening period. The canopy of a rice community fertilized by top dressing was cooler than that not fertilized in a 1999 field experiment. In an experiment using thermocouples to measure leaf temperature, a rice leaf with high chlorophyll content was also cooler than that with a low chlorophyll content. Transpiration resistance and transpiration rate were measured with a porometer. Transpiration rate was higher with increasing chlorophyll content in the leaf blade. Stomatal aperture is related to chlorophyll content in the leaf blade. High degree of stomatal aperture is caused by high chlorophyll content in the leaf blade. As degree of stomatal aperture increases, transpiration rate increases. Therefore the rice leaf got cooler with increasing chlorophyll content in leaf blade. Paddy rice communities with different chlorophyll contents were provided with fertilization of different nitrogen levels on basal and top dressing in a 2000 field experiment. Canopy temperature of the rice community with high chlorophyll content was 0.85°C cooler than that of the rice community with low chlorophyll content. Results of this study revealed that infrared remote sensing could detect difference in chlorophyll contents in rice communities and could be used in fertilizer management in paddy fields. (author)

  9. Scaling up stomatal conductance from leaf to canopy using a dual-leaf model for estimating crop evapotranspiration.

    Directory of Open Access Journals (Sweden)

    Risheng Ding

    Full Text Available The dual-source Shuttleworth-Wallace model has been widely used to estimate and partition crop evapotranspiration (λET. Canopy stomatal conductance (Gsc, an essential parameter of the model, is often calculated by scaling up leaf stomatal conductance, considering the canopy as one single leaf in a so-called "big-leaf" model. However, Gsc can be overestimated or underestimated depending on leaf area index level in the big-leaf model, due to a non-linear stomatal response to light. A dual-leaf model, scaling up Gsc from leaf to canopy, was developed in this study. The non-linear stomata-light relationship was incorporated by dividing the canopy into sunlit and shaded fractions and calculating each fraction separately according to absorbed irradiances. The model includes: (1 the absorbed irradiance, determined by separately integrating the sunlit and shaded leaves with consideration of both beam and diffuse radiation; (2 leaf area for the sunlit and shaded fractions; and (3 a leaf conductance model that accounts for the response of stomata to PAR, vapor pressure deficit and available soil water. In contrast to the significant errors of Gsc in the big-leaf model, the predicted Gsc using the dual-leaf model had a high degree of data-model agreement; the slope of the linear regression between daytime predictions and measurements was 1.01 (R2 = 0.98, with RMSE of 0.6120 mm s-1 for four clear-sky days in different growth stages. The estimates of half-hourly λET using the dual-source dual-leaf model (DSDL agreed well with measurements and the error was within 5% during two growing seasons of maize with differing hydrometeorological and management strategies. Moreover, the estimates of soil evaporation using the DSDL model closely matched actual measurements. Our results indicate that the DSDL model can produce more accurate estimation of Gsc and λET, compared to the big-leaf model, and thus is an effective alternative approach for estimating and

  10. Monitoring leaf photosynthesis with canopy spectral reflectance in rice

    International Nuclear Information System (INIS)

    Tian, Y.; Zhu, Y.; Cao, W.

    2005-01-01

    We determined the quantitative relationships between leaf photosynthetic characteristics (LPC) and canopy spectral reflectance under different water supply and nitrogen application rates in rice plants. The responses of reflectance at red radiation (680 nm) to different water contents and N rates were parallel to those of leaf net photosynthetic rate (PN). The relationships of reflectance at 680 nm and ratio index of R(810,680) (near infrared/red) to PN of different leaf positions and layers indicated that the top two full leaves were the best positions for quantitative monitoring of PN with remote sensing technique, and the index R(810,680) was the best ratio index for evaluating LPC. Testing of the models with independent data sets indicated that R(810,680) could well estimate PN of the top two leaves and canopy leaf photosynthetic potential. Hence R(810,680) can be used to monitor LPC in rice under diverse growing conditions

  11. Gas exchange and leaf contents in bell pepper under energized water and biofertilizer doses

    Directory of Open Access Journals (Sweden)

    Francisca R. M. Borges

    2016-06-01

    Full Text Available ABSTRACT The objective of this study was to evaluate the effect of energized water and bovine biofertilizer doses on the gas exchange and NPK contents in leaves of yellow bell pepper plants. The experiment was conducted at the experimental area of the Federal University of Ceará, in Fortaleza-CE, Brazil, from June to November 2011. The experiment was set in a randomized block design, in a split-plot scheme; the plots were composed of treatments with energized and non-energized water and the subplots of five doses of liquid biofertilizer (0, 250, 500, 750 and 1000 mL plant-1 week-1. The following variables were analyzed: transpiration, stomatal conductance, photosynthesis and leaf contents of nitrogen (N, phosphorus (P and potassium (K. Water energization did not allow significant increases in the analyzed variables. The use of biofertilizer as the only source of fertilization was sufficient to provide the nutrients N, P and K at appropriate levels for the bell pepper crop.

  12. [Effects of water table manipulation on leaf photosynthesis, morphology and growth of Phragmites australis and Imperata cylindrica in the reclaimed tidal wetland at Dongtan of Chongming Island, China].

    Science.gov (United States)

    Zhong, Qi-Cheng; Wang, Jiang-Tao; Zhou, Jian-Hong; Ou, Qiang; Wang, Kai-Yun

    2014-02-01

    During the growing season of 2011, the leaf photosynthesis, morphological and growth traits of Phragmites australis and Imperata cylindrica were investigated along a gradient of water table (low, medium and high) in the reclaimed tidal wetland at the Dongtan of Chongming Island in the Yangtze Estuary of China. A series of soil factors, i. e., soil temperature, moisture, salinity and inorganic nitrogen content, were also measured. During the peak growing season, leaf photosynthetic capacity of P. australis in the wetland with high water table was significantly lower than those in the wetland with low and medium water tables, and no difference was observed in leaf photosynthetic capacity of I. cylindrica at the three water tables. During the entire growing season, at the shoot level, the morphological and growth traits of P. australis got the optimum in the wetland with medium water table, but most of the morphological and growth traits of I. cylindrica had no significant differences at the three water tables. At the population level, the shoot density, leaf area index and aboveground biomass per unit area were the highest in the wetland with high water table for P. australis, but all of the three traits were the highest in the wetland with low water table for I. cylindrica. At the early growing season, the rhizome biomass of P. australis in the 0-20 cm soil layer had no difference at the three water tables, and the rhizome biomass of I. cylindrica in the 0-20 cm soil layer in the wetland with high water table was significantly lower than those in the wetland with low and medium water table. As a native hygrophyte before the reclamation, the variations of performances of P. australis at the three water tables were probably attributed to the differences in the soil factors as well as the intensity of competition from I. cylindrica. To appropriately manipulate water table in the reclaimed tidal wetland may restrict the growth and propagation of the mesophyte I

  13. Supercritical Water Oxidation Total Organic Carbon (TOC) Analysis

    Science.gov (United States)

    The work presented here is the evaluation of the modified wet‐oxidation method described as Supercritical Water Oxidation (SCWO) for the analysis of total organic carbon (TOC) in very difficult oil/gas produced water sample matrices.

  14. The Nissan LEAF electric powertrain

    Energy Technology Data Exchange (ETDEWEB)

    Nakazawa, Shinsuke [Nissan Motor Co., Ltd. (Japan)

    2011-07-01

    The need for CO{sub 2} reduction as a countermeasure to global warming, and to move away from our dependence on fossil fuels as a countermeasure to energy security are urgent issues. One of the ultimate goals to achieving these targets is to develop a 'Zero emission car' such as an electric vehicle or a fuel cell vehicle, along with the manufacturing of clean energy. Nissan have developed a new powertrain for the electric vehicle, and have installed it in the Nissan LEAF. Sales of the Nissan LEAF started in North America, Europe and Japan in 2010, with plans to sell it globally by 2012. In order to achieve an improved driving range, power performance and drivability performance, Nissan have adapted a high efficiency synchronous motor, a water-cooled inverter, and reducer. Moreover, the Nissan LEAF has the capability of a 3.3kW AC charge and a 50kW DC quick charge. This presentation will introduce the features of the electric powertrain adopted for Nissan LEAF. (orig.)

  15. Outside-xylem pathways, not xylem embolism, drive leaf hydraulic decline with dehydration

    Science.gov (United States)

    Leaf hydraulic supply is crucial to enable the maintenance of open stomata for CO2 capture and plant growth. During drought-induced leaf dehydration, the capacity for water flow through the leaf (Kleaf) declines, a phenomenon surprisingly attributed for the past fifty years solely to the formation o...

  16. Molecular, physiological and biochemical responses of Theobroma cacao L. genotypes to soil water deficit.

    Science.gov (United States)

    Santos, Ivanildes C Dos; Almeida, Alex-Alan Furtado de; Anhert, Dário; Conceição, Alessandro S da; Pirovani, Carlos P; Pires, José L; Valle, Raúl René; Baligar, Virupax C

    2014-01-01

    Six months-old seminal plants of 36 cacao genotypes grown under greenhouse conditions were subjected to two soil water regimes (control and drought) to assess, the effects of water deficit on growth, chemical composition and oxidative stress. In the control, soil moisture was maintained near field capacity with leaf water potentials (ΨWL) ranging from -0.1 to -0.5 MPa. In the drought treatment, the soil moisture was reduced gradually by withholding additional water until ΨWL reached values of between -2.0 to -2.5 MPa. The tolerant genotypes PS-1319, MO-20 and MA-15 recorded significant increases in guaiacol peroxidase activity reflecting a more efficient antioxidant metabolism. In relation to drought tolerance, the most important variables in the distinguishing contrasting groups were: total leaf area per plant; leaf, stem and total dry biomass; relative growth rate; plant shoot biomass and leaf content of N, Ca, and Mg. From the results of these analyses, six genotypes were selected with contrasting characteristics for tolerance to soil water deficit [CC-40, C. SUL-4 and SIC-2 (non-tolerant) and MA-15, MO-20, and PA-13 (tolerant)] for further assessment of the expression of genes NCED5, PP2C, psbA and psbO to water deficit. Increased expression of NCED5, PP2C, psbA and psbO genes were found for non-tolerant genotypes, while in the majority of tolerant genotypes there was repression of these genes, with the exception of PA-13 that showed an increased expression of psbA. Mutivariate analysis showed that growth variables, leaf and total dry biomass, relative growth rate as well as Mg content of the leaves were the most important factor in the classification of the genotypes as tolerant, moderately tolerant and sensitive to water deficit. Therefore these variables are reliable plant traits in the selection of plants tolerant to drought.

  17. The Role of Plant Water Storage on Water Fluxes within the Coupled Soil-Plant-Atmosphere System

    Science.gov (United States)

    Huang, C. W.; Duman, T.; Parolari, A.; Katul, G. G.

    2015-12-01

    Plant water storage (PWS) contributes to whole-plant transpiration (up to 50%), especially in large trees and during severe drought conditions. PWS also can impact water-carbon economy as well as the degree of resistance to drought. A 1-D porous media model is employed to accommodate transient water flow through the plant hydraulic system. This model provides a mechanistic representation of biophysical processes constraining water transport, accounting for plant hydraulic architecture and the nonlinear relation between stomatal aperture and leaf water potential when limited by soil water availability. Water transport within the vascular system from the stem base to the leaf-lamina is modeled using Richards's equation, parameterized with the hydraulic properties of the plant tissues. For simplicity, the conducting flow in the radial direction is not considered here and the capacitance at the leaf-lamina is assumed to be independent of leaf water potential. The water mass balance in the leaf lamina sets the upper boundary condition for the flow system, which links the leaf-level transpiration to the leaf water potential. Thus, the leaf-level gas exchange can be impacted by soil water availability through the water potential gradient from the leaf lamina to the soil, and vice versa. The root water uptake is modeled by a multi-layered macroscopic scheme to account for possible hydraulic redistribution (HR) in certain conditions. The main findings from the model calculations are that (1) HR can be diminished by the residual water potential gradient from roots to leaves at night due to aboveground capacitance, tree height, nocturnal transpiration or the combination of the three. The degree of reduction depends on the magnitude of residual water potential gradient; (2) nocturnal refilling to PWS elevates the leaf water potential that subsequently delays the onset of drought stress at the leaf; (3) Lifting water into the PWS instead of HR can be an advantageous strategy

  18. Natural recovery and leaf water potential after fire influenced by salvage logging and induced drought stress

    Directory of Open Access Journals (Sweden)

    D. Moya

    2013-01-01

    Full Text Available Salvage logging is one of the most common emergency actions in the short-term management after a fire. Several studies have been carried out and some obtained positive results which incite to carry it out but other, found negative effects on seedling establishment and regeneration. In addition, climatic changes will have large impacts on vegetation productivity and resilience since the regional models for south-eastern Spain predicts a rainfall decrease of about 20% and temperature increase of 4.5 ºC. Our aim was to determine how short-term forest management and induced drought affect the ecosystem recovery in Aleppo pine stands naturally recovered after a fire.In summer 2009, a mid-high severity fire burned 968 ha of Aleppo pine (Pinus halepensis Mill. forest in south-eastern Spain. Six months later, a salvage logging was carried out. The Aleppo pine recruitment was negligible. During summer 2010, twelve square plots (2m x 2m were set in the three scenarios: control, salvaged and drought induced. The surface cover and soil water availability for three dominant understory species were recorded in four field campaigns: Spring-2010, Fall-2010, Spring-2011 and Fall-2011.The season, management and the target species showed significant differences in growing and water stress. In general, Esparto grass showed lower water stress, mainly in Fall, a higher increase of total coverage. Both effects were showing their highest values in non-salvaged areas and no drought. Changes in leaf water potential and soil water content after the drought season influence the survival and development of individuals.Our results indicate that soil water content and ecosystem response can be modified by short-term silvicultural treatments. Therefore, management after fire could cause opposite effects to those initially foreseen, since they depend on fire severity, and type of ecosystem management response. So, their application must be evaluated and assessed before

  19. Fast-growing Acer rubrum differs from slow-growing Quercus alba in leaf, xylem and hydraulic trait coordination responses to simulated acid rain.

    Science.gov (United States)

    Medeiros, Juliana S; Tomeo, Nicholas J; Hewins, Charlotte R; Rosenthal, David M

    2016-08-01

    We investigated the effects of historic soil chemistry changes associated with acid rain, i.e., reduced soil pH and a shift from nitrogen (N)- to phosphorus (P)-limitation, on the coordination of leaf water demand and xylem hydraulic supply traits in two co-occurring temperate tree species differing in growth rate. Using a full-factorial design (N × P × pH), we measured leaf nutrient content, water relations, leaf-level and canopy-level gas exchange, total biomass and allocation, as well as stem xylem anatomy and hydraulic function for greenhouse-grown saplings of fast-growing Acer rubrum (L.) and slow-growing Quercus alba (L.). We used principle component analysis to characterize trait coordination. We found that N-limitation, but not P-limitation, had a significant impact on plant water relations and hydraulic coordination of both species. Fast-growing A. rubrum made hydraulic adjustments in response to N-limitation, but trait coordination was variable within treatments and did not fully compensate for changing allocation across N-availability. For slow-growing Q. alba, N-limitation engendered more strict coordination of leaf and xylem traits, resulting in similar leaf water content and hydraulic function across all treatments. Finally, low pH reduced the propensity of both species to adjust leaf water relations and xylem anatomical traits in response to nutrient manipulations. Our data suggest that a shift from N- to P-limitation has had a negative impact on the water relations and hydraulic function of A. rubrum to a greater extent than for Q. alba We suggest that current expansion of A. rubrum populations could be tempered by acidic N-deposition, which may restrict it to more mesic microsites. The disruption of hydraulic acclimation and coordination at low pH is emphasized as an interesting area of future study. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. An analytical approach for optimizing the leaf design of a multi-leaf collimator in a linear accelerator

    International Nuclear Information System (INIS)

    Topolnjak, R; Heide, U A van der

    2008-01-01

    In this study, we present an analytical approach for optimizing the leaf design of a multi-leaf collimator (MLC) in a linear accelerator. Because leaf designs vary between vendors, our goal is to characterize and quantify the effects of different compromises which have to be made between performance parameters. Subsequently, an optimal leaf design for an earlier proposed six-bank MLC which combines a high-resolution field-shaping ability with a large field size is determined. To this end a model of the linac is created that includes the following parameters: the source size, the maximum field size, the distance between source and isocenter, and the leaf's design parameters. First, the optimal radius of the leaf tip was found. This optimum was defined by the requirement that the fluence intensity should fall from 80% of the maximum value to 20% in a minimal distance, defining the width of the fluence penumbra. A second requirement was that this penumbra width should be constant when a leaf moves from one side of the field to the other. The geometric, transmission and total penumbra width (80-20%) were calculated depending on the design parameters. The analytical model is in agreement with Elekta, Varian and Siemens collimator designs. For leaves thinner than 4 cm, the transmission penumbra becomes dominant, and for leaves close to the source the geometric penumbra plays a role. Finally, by choosing the leaf thickness of 3.5 cm, 4 cm and 5 cm from the lowest to the highest bank, respectively, an optimal leaf design for a six-bank MLC is achieved

  1. Effects of light quality on leaf morphogenesis of a heterophyllous amphibious plant, Rotala hippuris.

    Science.gov (United States)

    Momokawa, Naoko; Kadono, Yasuro; Kudoh, Hiroshi

    2011-11-01

    For heterophyllous amphibious plants that experience fluctuating water levels, it is critical to control leaf development precisely in response to environmental cues that can serve as a quantitative index of water depth. Light quality can serve as such a cue because the ratio of red light relative to far-red light (R/FR) increases and blue-light intensity decreases with increasing water depth. Growth experiments were conducted to examine how R/FR and blue-light intensity alter leaf morphology of a heterophyllous amphibious plant, Rotala hippuris. Using combinations of far red (730 nm), red (660 nm) and blue (470 nm) light-emitting diodes (LEDs), growth experiments were used to quantitatively evaluate the effects of the R/FR ratio and blue-light intensity on leaf morphology. Under the natural light regime in an outside growth garden, R. hippuris produced distinct leaves under submerged and aerial conditions. R/FR and blue-light intensity were found to markedly affect heterophyllous leaf formation. Higher and lower R/FR caused leaf characters more typical of submerged and aerial leaves, respectively, in both aerial and submerged conditions, in accordance with natural distribution of leaf types and light under water. High blue light caused a shift of trait values toward those of typical aerial leaves, and the response was most prominent under conditions of R/FR that were expected near the water surface. R/FR and blue-light intensity provides quantitative cues for R. hippuris to detect water depth and determine the developmental fates of leaves, especially near the water surface. The utilization of these quantitative cues is expected to be important in habitats where plants experience water-level fluctuation.

  2. SUNLIT AND SHADED MAIZE CANOPY WATER LOSS UNDER VARIED WATER STRESS

    Directory of Open Access Journals (Sweden)

    Antonio Odair Santos

    1999-12-01

    Full Text Available ABSTRACT The precise estimation of transpiration from plant canopies is important for the monitoring of crop water use and management of many agricultural operations related to water use planning. The aim of this study was to estimate transpiration from sunlit and shaded fractions of a maize ( Zea mays L. canopy, using the Penman-Monteith energy balance equation with modifications introduced by Fuchs et al. (1987 and Fuchs & Cohen (1989. Estimated values were validated by a heat pulse system, which was used to measure stem sap flow and by a weighing lysimeter. A relationship between incident radiation and leaf stomatal conductance for critical levels of leaf water potential was used to estimate transpiration. Results showed that computed transpiration of the shaded canopy ranged from 27 to 45% of the total transpiration when fluctuations in atmospheric demand and the level of water stress were taken in account. Hourly and daily estimates of transpiration showed agreement with lysimeter and heat pulse measurements on the well-watered plots. For the water-limited plots the precision of the estimate decreased due to difficulties in simulating the canopy stomatal conductance.

  3. How Does Temperature Impact Leaf Size and Shape in Four Woody Dicot Species? Testing the Assumptions of Leaf Physiognomy-Climate Models

    Science.gov (United States)

    McKee, M.; Royer, D. L.

    2017-12-01

    The physiognomy (size and shape) of fossilized leaves has been used to reconstruct the mean annual temperature of ancient environments. Colder temperatures often select for larger and more abundant leaf teeth—serrated edges on leaf margins—as well as a greater degree of leaf dissection. However, to be able to accurately predict paleotemperature from the morphology of fossilized leaves, leaves must be able to react quickly and in a predictable manner to changes in temperature. We examined the extent to which temperature affects leaf morphology in four tree species: Carpinus caroliniana, Acer negundo, Ilex opaca, and Ostrya virginiana. Saplings of these species were grown in two growth cabinets under contrasting temperatures (17 and 25 °C). Compared to the cool treatment, in the warm treatment Carpinus caroliniana leaves had significantly fewer leaf teeth and a lower ratio of total number of leaf teeth to internal perimeter; and Acer negundo leaves had a significantly lower feret diameter ratio (a measure of leaf dissection). In addition, a two-way ANOVA tested the influence of temperature and species on leaf physiognomy. This analysis revealed that all plants, regardless of species, tended to develop more highly dissected leaves with more leaf teeth in the cool treatment. Because the cabinets maintained equivalent moisture, humidity, and CO2 concentration between the two treatments, these results demonstrate that these species could rapidly adapt to changes in temperature. However, not all of the species reacted identically to temperature changes. For example, Acer negundo, Carpinus caroliniana, and Ostrya virginiana all had a higher number of total teeth in the cool treatment compared to the warm treatment, but the opposite was true for Ilex opaca. Our work questions a fundamental assumption common to all models predicting paleotemperature from the physiognomy of fossilized leaves: a given climate will inevitably select for the same leaf physiognomy

  4. Betel leaf in stoma care.

    Science.gov (United States)

    Banu, Tahmina; Talukder, Rupom; Chowdhury, Tanvir Kabir; Hoque, Mozammel

    2007-07-01

    Construction of a stoma is a common procedure in pediatric surgical practice. For care of these stomas, commercially available devices such as ostomy bag, either disposable or of longer duration are usually used. These are expensive, particularly in countries like Bangladesh, and proper-sized ones are not always available. We have found an alternative for stoma care, betel leaf, which is suitable for Bangladeshis. We report the outcome of its use. After construction of stoma, at first zinc oxide paste was applied on the peristomal skin. A betel leaf with shiny, smooth surface outwards and rough surface inwards was put over the stoma with a hole made in the center according to the size of stoma. Another intact leaf covers the stomal opening. When bowel movement occurs, the overlying intact leaf was removed and the fecal matter was washed away from both. The leaves were reused after cleaning. Leaves were changed every 2 to 3 days. From June 1998 to December 2005, in the department of pediatric surgery, Chittagong Medical College and Hospital, Chittagong, Bangladesh, a total of 623 patients had exteriorization of bowel. Of this total, 495 stomas were cared for with betel leaves and 128 with ostomy bags. Of 623 children, 287 had sigmoid colostomy, 211 had transverse colostomy, 105 had ileostomy, and 20 had jejunostomy. Of the 495 children under betel leaf stoma care, 13 patients (2.6%) developed skin excoriation. There were no allergic reactions. Of the 128 patients using ostomy bag, 52 (40.65%) had skin excoriation. Twenty-four (18.75%) children developed some allergic reactions to adhesive. Monthly costs for betel leaves were 15 cents (10 BDT), whereas ostomy bags cost about US$24. In the care of stoma, betel leaves are cheap, easy to handle, nonirritant, and nonallergic.

  5. Nonmutagenicity of betel leaf and its antimutagenic action against environmental mutagens.

    Science.gov (United States)

    Nagabhushan, M; Amonkar, A J; D'Souza, A V; Bhide, S V

    1987-01-01

    Betel leaf (Piper betel) water and acetone extract are nonmutagenic in S. typhimurium strains with and without S9 mix. Both the extracts suppress the mutagenicity of betel quid mutagens in a dose dependent manner. Moreover both the extracts of betel leaf reduce the mutagenicity of benzo(a)pyrene and dimethylbenzanthracene. Acetone extract is more potent than water extract in inhibiting mutagenicity of environmental mutagens.

  6. Oreganum vulgare Linn. leaf: An Extensive Pharmacognostical and Phytochemical Quality Assessment

    Directory of Open Access Journals (Sweden)

    Veni Bharti

    2013-08-01

    Full Text Available Purpose: Standardization and detailed pharmacognostical studies of Oreganum vulgare Linn. leaf for authentication and commercial utilization. Methods: Oreganum vulgare Linn. leaf was with standardization according to standard procedures described in WHO, 2011 and I.P. 1996. Results: The physicochemical parameters total ash, acid insoluble ash, water soluble ash and sulphated ash were found to be 11.5%, 11%, 5, 10.5% w/w respectively. Foaming index was found be <100. The trace elements were found to be copper, lead, cadmium, zinc, cobalt, manganese, nickel and copper in ethanol extract and phytochemical screening of aqueous and ethanol extract showed the presence of carbohydrates, flavonoids, anthocyanins, phenolic compounds etc. Conclusion: The standardization parameters viz. physico-chemical parameters, macroscopy, microscopy, taxonomy, anatomy and preliminary phytochemical screening, microbial and aflatoxin count, HPTLC profile is being reported to help in authentication and development of monograph of this plant.

  7. [Study on membrane type leaf water evaporation inhibitors for improving effect of preventing diseases and pest controlling of Lycium barbarum].

    Science.gov (United States)

    Wang, Dan-Dan; Lv, Zhe; Xu, Chang-Qing; Liu, Sai; Chen, Jun; Peng, Xiao; Wu, Yan

    2018-01-01

    Through indoor and field comparative experiments, the properties of membrane type leaf evaporation inhibitors and its effects on photosynthesis of Lycium barbarum and compatibility and synergistic of pesticide were studied. The evaporation inhibitors and L. barbarum were chosen to investigate the suppression of water evaporation and the compatibility with pesticides. The effect of evaporation inhibitors on photosynthesis of L. barbarum leaves was determined by the chlorophyll fluorescence imaging system. The results showed that water evaporation of L. barbarum leaves of different leaf age were evidently suppressed after treated with evaporation inhibitor. The inhibitor was well compatible with pesticide and effectively improved the pesticide efficacy,and had no significant effect on chlorophyll fluorescence parameters. It is concluded that the evaporation inhibitor has good compatibility with the pesticide, and has remarkable effect of restraining moisture evaporation, which make it can be used for reducing the dosage and improving the efficacy of the pesticide in the field of L. barbarum. Copyright© by the Chinese Pharmaceutical Association.

  8. Foliar uptake of fog water and transport belowground alleviates drought effects in the cloud forest tree species, Drimys brasiliensis (Winteraceae).

    Science.gov (United States)

    Eller, Cleiton B; Lima, Aline L; Oliveira, Rafael S

    2013-07-01

    Foliar water uptake (FWU) is a common water acquisition mechanism for plants inhabiting temperate fog-affected ecosystems, but the prevalence and consequences of this process for the water and carbon balance of tropical cloud forest species are unknown. We performed a series of experiments under field and glasshouse conditions using a combination of methods (sap flow, fluorescent apoplastic tracers and stable isotopes) to trace fog water movement from foliage to belowground components of Drimys brasiliensis. In addition, we measured leaf water potential, leaf gas exchange, leaf water repellency and growth of plants under contrasting soil water availabilities and fog exposure in glasshouse experiments to evaluate FWU effects on the water and carbon balance of D. brasiliensis saplings. Fog water diffused directly through leaf cuticles and contributed up to 42% of total foliar water content. FWU caused reversals in sap flow in stems and roots of up to 26% of daily maximum transpiration. Fog water transported through the xylem reached belowground pools and enhanced leaf water potential, photosynthesis, stomatal conductance and growth relative to plants sheltered from fog. Foliar uptake of fog water is an important water acquisition mechanism that can mitigate the deleterious effects of soil water deficits for D. brasiliensis. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  9. Relationships of leaf dark respiration to leaf nitrogen, specific leaf area and leaf life-span: a test across biomes and functional groups.

    Science.gov (United States)

    Reich, Peter B; Walters, Michael B; Ellsworth, David S; Vose, James M; Volin, John C; Gresham, Charles; Bowman, William D

    1998-05-01

    Based on prior evidence of coordinated multiple leaf trait scaling, we hypothesized that variation among species in leaf dark respiration rate (R d ) should scale with variation in traits such as leaf nitrogen (N), leaf life-span, specific leaf area (SLA), and net photosynthetic capacity (A max ). However, it is not known whether such scaling, if it exists, is similar among disparate biomes and plant functional types. We tested this idea by examining the interspecific relationships between R d measured at a standard temperature and leaf life-span, N, SLA and A max for 69 species from four functional groups (forbs, broad-leafed trees and shrubs, and needle-leafed conifers) in six biomes traversing the Americas: alpine tundra/subalpine forest, Colorado; cold temperate forest/grassland, Wisconsin; cool temperate forest, North Carolina; desert/shrubland, New Mexico; subtropical forest, South Carolina; and tropical rain forest, Amazonas, Venezuela. Area-based R d was positively related to area-based leaf N within functional groups and for all species pooled, but not when comparing among species within any site. At all sites, mass-based R d (R d-mass ) decreased sharply with increasing leaf life-span and was positively related to SLA and mass-based A max and leaf N (leaf N mass ). These intra-biome relationships were similar in shape and slope among sites, where in each case we compared species belonging to different plant functional groups. Significant R d-mass -N mass relationships were observed in all functional groups (pooled across sites), but the relationships differed, with higher R d at any given leaf N in functional groups (such as forbs) with higher SLA and shorter leaf life-span. Regardless of biome or functional group, R d-mass was well predicted by all combinations of leaf life-span, N mass and/or SLA (r 2 ≥ 0.79, P morphological, chemical and metabolic traits.

  10. Climate influences the leaf area/sapwood area ratio in Scots pine.

    Science.gov (United States)

    Mencuccini, M; Grace, J

    1995-01-01

    We tested the hypothesis that the leaf area/sapwood area ratio in Scots pine (Pinus sylvestris L.) is influenced by site differences in water vapor pressure deficit of the air (D). Two stands of the same provenance were selected, one in western Scotland and one in eastern England, so that effects resulting from age, genetic variability, density and fertility were minimized. Compared with the Scots pine trees at the cooler and wetter site in Scotland, the trees at the warmer and drier site in England produced less leaf area per unit of conducting sapwood area both at a stem height of 1.3 m and at the base of the live crown, whereas stem permeability was similar at both sites. Also, trees at the drier site had less leaf area per unit branch cross-sectional area at the branch base than trees at the wetter site. For each site, the average values for leaf area, sapwood area and permeability were used, together with values of transpiration rates at different D, to calculate average stem water potential gradients. Changes in the leaf area/sapwood area ratio acted to maintain a similar water potential gradient in the stems of trees at both sites despite climatic differences between the sites.

  11. Leaf-IT: An Android application for measuring leaf area.

    Science.gov (United States)

    Schrader, Julian; Pillar, Giso; Kreft, Holger

    2017-11-01

    The use of plant functional traits has become increasingly popular in ecological studies because plant functional traits help to understand key ecological processes in plant species and communities. This also includes changes in diversity, inter- and intraspecific interactions, and relationships of species at different spatiotemporal scales. Leaf traits are among the most important traits as they describe key dimensions of a plant's life history strategy. Further, leaf area is a key parameter with relevance for other traits such as specific leaf area, which in turn correlates with leaf chemical composition, photosynthetic rate, leaf longevity, and carbon investment. Measuring leaf area usually involves the use of scanners and commercial software and can be difficult under field conditions. We present Leaf-IT, a new smartphone application for measuring leaf area and other trait-related areas. Leaf-IT is free, designed for scientific purposes, and runs on Android 4 or higher. We tested the precision and accuracy using objects with standardized area and compared the area measurements of real leaves with the well-established, commercial software WinFOLIA using the Altman-Bland method. Area measurements of standardized objects show that Leaf-IT measures area with high accuracy and precision. Area measurements with Leaf-IT of real leaves are comparable to those of WinFOLIA. Leaf-IT is an easy-to-use application running on a wide range of smartphones. That increases the portability and use of Leaf-IT and makes it possible to measure leaf area under field conditions typical for remote locations. Its high accuracy and precision are similar to WinFOLIA. Currently, its main limitation is margin detection of damaged leaves or complex leaf morphologies.

  12. Investigation of the influence of liquid water films on O3 and PAN deposition on plant leaf surfaces treated with organic / inorganic compounds

    Science.gov (United States)

    Sun, Shang; Moravek, Alexander; von der Heyden, Lisa; Held, Andreas; Kesselmeier, Jürgen; Sörgel, Matthias

    2016-04-01

    Liquid water films on environmental surfaces play an important role in various fields of interest (Burkhardt and Eiden, 1994). For example, the deposition of water soluble trace gases could be increased by surface moisture. Chameides and Stelson (1992) found out that the dissolution of trace gases in airborne particulate matter increases with rising water/solid ratio of the particles. Further, Flechard et al. (1999) concluded that deliquescent salt particles represent a potential sink for trace gases, depending on their chemical property. The formation of surface water films and its influence on the gas deposition was proposed by many previous studies (Fuentes and Gillespie, 1992, Burkhardt and Eiden, 1994, van Hove et al., 1989, Burkhardt et al., 1999, Flechard et al., 1999). In this study we investigate the influence of leaf surface water films on the deposition of O3 and PAN under controlled laboratory conditions. A twin cuvette system described in Sun et al. (2015) was used to control the environmental parameters such as light, temperature, trace gas mixing ratio and humidity. Furthermore, the leaf surface was treated with various organic and inorganic solutions to investigate the influence of deposited compounds on the electrical surface conductance of the leaves and the surface deposition of O3 and PAN at various relative humidities. The result shows that RHcrit, where the electrical surface conductance (G) increases exponentially, was 40 % during the light period and 50 % during the dark period. Furthermore, we observed that the formation of the leaf surface liquid film was depended on the deposited compounds on the leaf cuticles. For the O3 deposition on plants (Quercus ilex) a clear enhancement at rising environmental air humidity under light and dark condition was found. The increase during light conditions can be related partly to increasing stomatal conductance with higher RH. From the non-stomatal deposition measured in dark experiments, we could

  13. A comprehensive analysis of the physiological and anatomical components involved in higher water loss rates after leaf development at high humidity

    NARCIS (Netherlands)

    Fanourakis, D.; Heuvelink, E.; Pinto De Carvalho, S.M.

    2013-01-01

    To better understand the poor regulation of water loss after leaf development at high relative air humidity (RH), the relative importance of the physiological and anatomical components was analyzed focusing on cultivars with a contrasting sensitivity to elevated RH. The stomatal responsiveness to

  14. Cassava brown streak disease effects on leaf metabolites and ...

    African Journals Online (AJOL)

    Cassava brown streak disease effects on leaf metabolites and pigment accumulation. ... Total reducing sugar and starch content also dropped significantly (-30 and -60%, respectively), much as NASE 14 maintained a relatively higher amount of carbohydrates. Leaf protein levels were significantly reduced at a rate of 0.07 ...

  15. Leaf gas exchange of understory spruce-fir saplings in relict cloud forests, southern Appalachian Mountains, USA

    Energy Technology Data Exchange (ETDEWEB)

    Reinhardt, K.; Smith, W.K. [Wake Forest Univ., Winston-Salem, NC (United States). Dept. of Biology

    2008-01-15

    Global climate change is expected to increase regional cloud ceiling levels in many mountainous forested areas of the world. This study investigated environmental influences on the gas exchange physiology of understory red spruce and Fraser fir trees at 2 sites in the Appalachian mountains. The study hypothesized that the humid, cloudy environment would influence the photosynthetic performance of the trees, and that the species would adapt to low, diffuse light. The study also predicted that leaf conductance to carbon dioxide (CO{sub 2}) would be high as a result of low leaf-to-air-vapour pressure deficit (LAVD). The study demonstrated that leaf conductance decreased exponentially as LAVD increased. Predawn leaf water potentials remained stable, while late afternoon values declined. It was concluded that leaf gas exchange was correlated with the response of leaf conductance and LAVD. The cloudy, humid environment strongly influenced tree leaf gas exchange and water relations. It was suggested that further research is needed to investigate cloud impacts on carbon gain and water relations. 72 refs., 1 tab., 8 figs.

  16. Inheritance of okra leaf type in different genetic backgrounds and its ...

    African Journals Online (AJOL)

    use

    2011-11-21

    Nov 21, 2011 ... trait was studied in three cross combinations involving a common okra leaf parent ... pests with reduced leaf area allowing better air flow and maximum sunlight .... Irrigation both by canal and turbine water was applied to the.

  17. Limited acclimation in leaf anatomy to experimental drought in tropical rainforest trees.

    Science.gov (United States)

    Binks, Oliver; Meir, Patrick; Rowland, Lucy; da Costa, Antonio Carlos Lola; Vasconcelos, Steel Silva; de Oliveira, Alex Antonio Ribeiro; Ferreira, Leandro; Mencuccini, Maurizio

    2016-12-01

    Dry periods are predicted to become more frequent and severe in the future in some parts of the tropics, including Amazonia, potentially causing reduced productivity, higher tree mortality and increased emissions of stored carbon. Using a long-term (12 year) through-fall exclusion (TFE) experiment in the tropics, we test the hypothesis that trees produce leaves adapted to cope with higher levels of water stress, by examining the following leaf characteristics: area, thickness, leaf mass per area, vein density, stomatal density, the thickness of palisade mesophyll, spongy mesophyll and both of the epidermal layers, internal cavity volume and the average cell sizes of the palisade and spongy mesophyll. We also test whether differences in leaf anatomy are consistent with observed differential drought-induced mortality responses among taxa, and look for relationships between leaf anatomy, and leaf water relations and gas exchange parameters. Our data show that trees do not produce leaves that are more xeromorphic in response to 12 years of soil moisture deficit. However, the drought treatment did result in increases in the thickness of the adaxial epidermis (TFE: 20.5 ± 1.5 µm, control: 16.7 ± 1.0 µm) and the internal cavity volume (TFE: 2.43 ± 0.50 mm 3 cm -2 , control: 1.77 ± 0.30 mm 3 cm -2 ). No consistent differences were detected between drought-resistant and drought-sensitive taxa, although interactions occurred between drought-sensitivity status and drought treatment for the palisade mesophyll thickness (P = 0.034) and the cavity volume of the leaves (P = 0.025). The limited response to water deficit probably reflects a tight co-ordination between leaf morphology, water relations and photosynthetic properties. This suggests that there is little plasticity in these aspects of plant anatomy in these taxa, and that phenotypic plasticity in leaf traits may not facilitate the acclimation of Amazonian trees to the predicted future reductions in dry

  18. Shrub type dominates the vertical distribution of leaf C : N : P stoichiometry across an extensive altitudinal gradient

    Science.gov (United States)

    Zhao, Wenqiang; Reich, Peter B.; Yu, Qiannan; Zhao, Ning; Yin, Chunying; Zhao, Chunzhang; Li, Dandan; Hu, Jun; Li, Ting; Yin, Huajun; Liu, Qing

    2018-04-01

    Understanding leaf stoichiometric patterns is crucial for improving predictions of plant responses to environmental changes. Leaf stoichiometry of terrestrial ecosystems has been widely investigated along latitudinal and longitudinal gradients. However, very little is known about the vertical distribution of leaf C : N : P and the relative effects of environmental parameters, especially for shrubs. Here, we analyzed the shrub leaf C, N and P patterns in 125 mountainous sites over an extensive altitudinal gradient (523-4685 m) on the Tibetan Plateau. Results showed that the shrub leaf C and C : N were 7.3-47.5 % higher than those of other regional and global flora, whereas the leaf N and N : P were 10.2-75.8 % lower. Leaf C increased with rising altitude and decreasing temperature, supporting the physiological acclimation mechanism that high leaf C (e.g., alpine or evergreen shrub) could balance the cell osmotic pressure and resist freezing. The largest leaf N and high leaf P occurred in valley region (altitude 1500 m), likely due to the large nutrient leaching from higher elevations, faster litter decomposition and nutrient resorption ability of deciduous broadleaf shrub. Leaf N : P ratio further indicated increasing N limitation at higher altitudes. Interestingly, drought severity was the only climatic factor positively correlated with leaf N and P, which was more appropriate for evaluating the impact of water status than precipitation. Among the shrub ecosystem and functional types (alpine, subalpine, montane, valley, evergreen, deciduous, broadleaf, and conifer), their leaf element contents and responses to environments were remarkably different. Shrub type was the largest contributor to the total variations in leaf stoichiometry, while climate indirectly affected the leaf C : N : P via its interactive effects on shrub type or soil. Collectively, the large heterogeneity in shrub type was the most important factor explaining the overall leaf C : N : P variations

  19. Effect of progressive drought stress on growth, leaf gas exchange, and antioxidant production in two maize cultivars.

    Science.gov (United States)

    Anjum, Shakeel Ahmad; Tanveer, Mohsin; Ashraf, Umair; Hussain, Saddam; Shahzad, Babar; Khan, Imran; Wang, Longchang

    2016-09-01

    Drought stress is one of the major environmental factors responsible for reduction in crop productivity. In the present study, responses of two maize cultivars (Rung Nong 35 and Dong Dan 80) were examined to explicate the growth, yield, leaf gas exchange, leaf water contents, osmolyte accumulation, membrane lipid peroxidation, and antioxidant activity under progressive drought stress. Maize cultivars were subjected to varying field capacities (FC) viz., well-watered (80 % FC) and drought-stressed (35 % FC) at 45 days after sowing. The effects of drought stress were analyzed at 5, 10, 15, 20, ad 25 days after drought stress (DAS) imposition. Under prolonged drought stress, Rung Nong 35 exhibited higher reduction in growth and yield as compared to Dong Dan 80. Maize cultivar Dong Dan 80 showed higher leaf relative water content (RWC), free proline, and total carbohydrate accumulation than Run Nong 35. Malondialdehyde (MDA) and superoxide anion were increased with prolongation of drought stress, with higher rates in cultivar Run Nong 35 than cultivar Dong Dan 80. Higher production of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) and glutathione reductase (GR) resulted in improved growth and yield in Dong Dan 80. Overall, the cultivar Dong Dan 80 was better able to resist the detrimental effects of progressive drought stress as indicated by better growth and yield due to higher antioxidant enzymes, reduced lipid peroxidation, better accumulation of osmolytes, and maintenance of tissue water contents.

  20. The dosimetric impact of leaf interdigitation and leaf width on VMAT treatment planning in Pinnacle: comparing Pareto fronts

    International Nuclear Information System (INIS)

    Van Kesteren, Z; Janssen, T M; Damen, E; Van Vliet-Vroegindeweij, C

    2012-01-01

    To evaluate in an objective way the effect of leaf interdigitation and leaf width on volumetric modulated arc therapy plans in Pinnacle. Three multileaf collimators (MLCs) were modeled: two 10 mm leaf width MLCs, with and without interdigitating leafs, and a 5 mm leaf width MLC with interdigitating leafs. Three rectum patients and three prostate patients were used for the planning study. In order to compare treatment techniques in an objective way, a Pareto front comparison was carried out. 200 plans were generated in an automated way, per patient per MLC model, resulting in a total of 3600 plans. From these plans, Pareto-optimal plans were selected which were evaluated for various dosimetric variables. The capability of leaf interdigitation showed little dosimetric impact on the treatment plans, when comparing the 10 mm leaf width MLC with and without leaf interdigitation. When comparing the 10 mm leaf width MLC with the 5 mm leaf width MLC, both with interdigitating leafs, improvement in plan quality was observed. For both patient groups, the integral dose was reduced by 0.6 J for the thin MLC. For the prostate patients, the mean dose to the anal sphincter was reduced by 1.8 Gy and the conformity of the V 95% was reduced by 0.02 using the thin MLC. The V 65% of the rectum was reduced by 0.1% and the dose homogeneity with 1.5%. For rectum patients, the mean dose to the bowel was reduced by 1.4 Gy and the mean dose to the bladder with 0.8 Gy for the thin MLC. The conformity of the V 95% was equivalent for the 10 and 5 mm leaf width MLCs for the rectum patients. We have objectively compared three types of MLCs in a planning study for prostate and rectum patients by analyzing Pareto-optimal plans which were generated in an automated way. Interdigitation of MLC leafs does not generate better plans using the SmartArc algorithm in Pinnacle. Changing the MLC leaf width from 10 to 5 mm generates better treatment plans although the clinical relevance remains to be proven

  1. The dosimetric impact of leaf interdigitation and leaf width on VMAT treatment planning in Pinnacle: comparing Pareto fronts.

    Science.gov (United States)

    van Kesteren, Z; Janssen, T M; Damen, E; van Vliet-Vroegindeweij, C

    2012-05-21

    To evaluate in an objective way the effect of leaf interdigitation and leaf width on volumetric modulated arc therapy plans in Pinnacle. Three multileaf collimators (MLCs) were modeled: two 10 mm leaf width MLCs, with and without interdigitating leafs, and a 5 mm leaf width MLC with interdigitating leafs. Three rectum patients and three prostate patients were used for the planning study. In order to compare treatment techniques in an objective way, a Pareto front comparison was carried out. 200 plans were generated in an automated way, per patient per MLC model, resulting in a total of 3600 plans. From these plans, Pareto-optimal plans were selected which were evaluated for various dosimetric variables. The capability of leaf interdigitation showed little dosimetric impact on the treatment plans, when comparing the 10 mm leaf width MLC with and without leaf interdigitation. When comparing the 10 mm leaf width MLC with the 5 mm leaf width MLC, both with interdigitating leafs, improvement in plan quality was observed. For both patient groups, the integral dose was reduced by 0.6 J for the thin MLC. For the prostate patients, the mean dose to the anal sphincter was reduced by 1.8 Gy and the conformity of the V(95%) was reduced by 0.02 using the thin MLC. The V(65%) of the rectum was reduced by 0.1% and the dose homogeneity with 1.5%. For rectum patients, the mean dose to the bowel was reduced by 1.4 Gy and the mean dose to the bladder with 0.8 Gy for the thin MLC. The conformity of the V(95%) was equivalent for the 10 and 5 mm leaf width MLCs for the rectum patients. We have objectively compared three types of MLCs in a planning study for prostate and rectum patients by analyzing Pareto-optimal plans which were generated in an automated way. Interdigitation of MLC leafs does not generate better plans using the SmartArc algorithm in Pinnacle. Changing the MLC leaf width from 10 to 5 mm generates better treatment plans although the clinical relevance remains

  2. NESDIS Blended Total Precipitable Water (TPW) Products

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The blended Total Precipitable Water (TPW) product is derived from multiple sensors/satellites. The Percentage of TPW normal (PCT), or TPW anomaly, shows the...

  3. The effect of water deficit stress and nitrogen fertilizer levels on morphology traits, yield and leaf area index in maize

    International Nuclear Information System (INIS)

    Moosavi, S.G.

    2012-01-01

    In order to study the effect of water deficit stress at different growth stages and N fertilizer levels on morphological traits, yield and yield components of maize cv. Single Cross 704, an experiment was conducted as a split-plot based on a Randomized Complete Block Design with three replications. The main plot included irrigation at four levels (irrigation stop at 10-leaf, tasselling and grain-filling stages and optimum irrigation) and the sub-plot was N fertilizer at three levels (75, 150 and 225 kg N/ha). The results of analysis of variance showed that water-deficit stress and N fertilizer level significantly affected leaf area index at silking stage, ear length, grain number per ear, 1000-grain weight and grain yield. Stem diameter, ear diameter and harvest index were only affected by irrigation treatments and the interaction between irrigation and N level did not significantly affect the studied traits. Means comparison indicated that ear diameter under optimum irrigation was higher than that under the treatments of irrigation stop at 8-leaf, tasselling and grain-filling stages by 29.9, 19.1 and 33.5%, respectively; and ear length was higher than them by 38.1, 28.9 and 25.2%, respectively. Moreover, the highest grain number per ear, 1000-grain weight and grain yield were obtained under optimum irrigation treatment, and irrigation stop at 10-leaf, tasselling and grain-filling stages decreased grain yield by 52.8, 66.4 and 44.9%, respectively; and it decreased grain number/ear by 45.9, 59.3 and 30.1%, respectively. In addition, optimum irrigation treatment with mean 1000-grain weight of 289.2 g was significantly superior over other irrigation stop treatments by 27.6-42.8% and produced the highest leaf area index at silking stage (4.1). Means comparison of traits at different N levels indicated that N level of 225 kg/ha produced the highest ear length (17.82 cm), grain number per ear (401.9), 1000-grain weight (258.8 g), leaf area index at silking stage (4

  4. Method for continuous measurement of export from a leaf

    International Nuclear Information System (INIS)

    Geiger, D.R.; Fondy, B.R.

    1979-01-01

    Export of labeled material derived by continuous photosynthesis in 14 CO 2 was monitored with a Geiger-Mueller detector positioned next to an exporting leaf blade. Rate of export of labeled material was calculated from the difference between rates of retention and net photosynthesis of labeled carbon for the observed leaf. Given certain conditions, including nearly constant distribution of labeled material among minor veins and various types of cells, count rate data for the source leaf can be coverted to rate of export of carbon. Changes in counting efficiency resulting from changes in leaf water status can be corrected for with data from a transducer which measures leaf thickness. Export data agreed with data obtained by monitoring the arrival of 14 C in the sink region; isolated leaves gave values near zero for export of labeled carbon from a given leaf on an intact plant. The technique detects changes in export with a resolution of 10 to 20 minutes

  5. Dynamics of leaf gas exchange, xylem and phloem transport, water potential and carbohydrate concentration in a realistic 3-D model tree crown.

    Science.gov (United States)

    Nikinmaa, Eero; Sievänen, Risto; Hölttä, Teemu

    2014-09-01

    Tree models simulate productivity using general gas exchange responses and structural relationships, but they rarely check whether leaf gas exchange and resulting water and assimilate transport and driving pressure gradients remain within acceptable physical boundaries. This study presents an implementation of the cohesion-tension theory of xylem transport and the Münch hypothesis of phloem transport in a realistic 3-D tree structure and assesses the gas exchange and transport dynamics. A mechanistic model of xylem and phloem transport was used, together with a tested leaf assimilation and transpiration model in a realistic tree architecture to simulate leaf gas exchange and water and carbohydrate transport within an 8-year-old Scots pine tree. The model solved the dynamics of the amounts of water and sucrose solute in the xylem, cambium and phloem using a fine-grained mesh with a system of coupled ordinary differential equations. The simulations predicted the observed patterns of pressure gradients and sugar concentration. Diurnal variation of environmental conditions influenced tree-level gradients in turgor pressure and sugar concentration, which are important drivers of carbon allocation. The results and between-shoot variation were sensitive to structural and functional parameters such as tree-level scaling of conduit size and phloem unloading. Linking whole-tree-level water and assimilate transport, gas exchange and sink activity opens a new avenue for plant studies, as features that are difficult to measure can be studied dynamically with the model. Tree-level responses to local and external conditions can be tested, thus making the approach described here a good test-bench for studies of whole-tree physiology.

  6. Characterization, antibacterial, total antioxidant, scavenging, reducing power and ion chelating activities of green synthesized silver, copper and titanium dioxide nanoparticles using Artemisia haussknechtii leaf extract.

    Science.gov (United States)

    Alavi, Mehran; Karimi, Naser

    2017-12-12

    Recently, major problem related to pathogenic bacteria is augmentation of antibiotic resistance which has been changed treatment and recovery of millions of infectious patients. The present study reports an eco-friendly, rapid and easy method for synthesis of silver (Ag), copper (Cu) and titanium dioxide (TiO 2 ) nanoparticles (NPs) using Artemisia haussknechtii leaf aqueous extract with antibacterial activities against multi-drug resistance (MDR) bacteria species. Three different concentrations (0.001, 0.01 and 0.1 M) of AgNO 3 , CuSO 4 and TiO (OH) 2 were investigated for obtaining optimum NPs green synthesis. Total phenolic content, total flavonoid content of leaf extract and total antioxidant activity (DPPH) assay were determined as radical scavenging methods. UV-Visible spectroscopy, Fourier transform infrared spectroscopy analysis, X-ray diffraction, energy dispersive X-ray spectroscopy, field emission scanning electron microscope and atomic force microscopy (AFM) were used due to NPs characterization. The size average of the Ag, Cu and TiO 2 NPs obtained were respectively 10.69 ± 5.55, 35.36 ± 44.4 and 92.58 ± 56.98 nm. In the case of antibacterial assay, disc diffusion assay, minimum inhibitory concentration, minimum bactericidal concentration, bacterial growth and morphology of four MDR species Staphylococcus aureus ATCC 43300, Staphylococcus epidermidis ATCC 12258, Serratia marcescens ATTC13880 and Escherichia coli ATCC 25922 were evaluated. Results of this study demonstrated that A. haussknechtii leaf extract with various groups of phytochemicals such as phenols and flavonoids had suitable ability in green synthesis of Ag, Cu and TiO 2 NPs. Also, Ag and Cu NPs had more antibacterial activities compared to TiO 2 NPs.

  7. Molecular modeling of the green leaf volatile methyl salicylate on atmospheric air/water interfaces.

    Science.gov (United States)

    Liyana-Arachchi, Thilanga P; Hansel, Amie K; Stevens, Christopher; Ehrenhauser, Franz S; Valsaraj, Kalliat T; Hung, Francisco R

    2013-05-30

    Methyl salicylate (MeSA) is a green leaf volatile (GLV) compound that is emitted in significant amounts by plants, especially when they are under stress conditions. GLVs can then undergo chemical reactions with atmospheric oxidants, yielding compounds that contribute to the formation of secondary organic aerosols (SOAs). We investigated the adsorption of MeSA on atmospheric air/water interfaces at 298 K using thermodynamic integration (TI), potential of mean force (PMF) calculations, and classical molecular dynamics (MD) simulations. Our molecular models can reproduce experimental results of the 1-octanol/water partition coefficient of MeSA. A deep free energy minimum was found for MeSA at the air/water interface, which is mainly driven by energetic interactions between MeSA and water. At the interface, the oxygenated groups in MeSA tend to point toward the water side of the interface, with the aromatic group of MeSA lying farther away from water. Increases in the concentrations of MeSA lead to reductions in the height of the peaks in the MeSA-MeSA g(r) functions, a slowing down of the dynamics of both MeSA and water at the interface, and a reduction in the interfacial surface tension. Our results indicate that MeSA has a strong thermodynamic preference to remain at the air/water interface, and thus chemical reactions with atmospheric oxidants are more likely to take place at this interface, rather than in the water phase of atmospheric water droplets or in the gas phase.

  8. Total body water and total body potassium in anorexia nervosa

    Energy Technology Data Exchange (ETDEWEB)

    Dempsey, D.T.; Crosby, L.O.; Lusk, E.; Oberlander, J.L.; Pertschuk, M.J.; Mullen, J.L.

    1984-08-01

    In the ill hospitalized patient with clinically relevant malnutrition, there is a measurable decrease in the ratio of the total body potassium to total body water (TBK/TBW) and a detectable increase in the ratio of total exchangeable sodium to total exchangeable potassium (Nae/Ke). To evaluate body composition analyses in anorexia nervosa patients with chronic uncomplicated semistarvation, TBK and TBW were measured by whole body K40 counting and deuterium oxide dilution in 10 females with stable anorexia nervosa and 10 age-matched female controls. The ratio of TBK/TBW was significantly (p less than 0.05) higher in anorexia nervosa patients than controls. The close inverse correlation found in published studies between TBK/TBW and Nae/Ke together with our results suggest that in anorexia nervosa, Nae/Ke may be low or normal. A decreased TBK/TBW is not a good indicator of malnutrition in the anorexia nervosa patient. The use of a decreased TBK/TBW ratio or an elevated Nae/Ke ratio as a definition of malnutrition may result in inappropriate nutritional management in the patient with severe nonstressed chronic semistarvation.

  9. Total body water and total body potassium in anorexia nervosa

    International Nuclear Information System (INIS)

    Dempsey, D.T.; Crosby, L.O.; Lusk, E.; Oberlander, J.L.; Pertschuk, M.J.; Mullen, J.L.

    1984-01-01

    In the ill hospitalized patient with clinically relevant malnutrition, there is a measurable decrease in the ratio of the total body potassium to total body water (TBK/TBW) and a detectable increase in the ratio of total exchangeable sodium to total exchangeable potassium (Nae/Ke). To evaluate body composition analyses in anorexia nervosa patients with chronic uncomplicated semistarvation, TBK and TBW were measured by whole body K40 counting and deuterium oxide dilution in 10 females with stable anorexia nervosa and 10 age-matched female controls. The ratio of TBK/TBW was significantly (p less than 0.05) higher in anorexia nervosa patients than controls. The close inverse correlation found in published studies between TBK/TBW and Nae/Ke together with our results suggest that in anorexia nervosa, Nae/Ke may be low or normal. A decreased TBK/TBW is not a good indicator of malnutrition in the anorexia nervosa patient. The use of a decreased TBK/TBW ratio or an elevated Nae/Ke ratio as a definition of malnutrition may result in inappropriate nutritional management in the patient with severe nonstressed chronic semistarvation

  10. [Characterization of kale (Brassica oberacea var acephala) under thallium stress by in situ attenuated total reflection FTIR].

    Science.gov (United States)

    Yao, Yan; Zhang, Ping; Wang, Zhen-Chun; Chen, Yong-Heng

    2009-01-01

    The experiment was designed based on consumption of carbon dioxide through the photosynthesis of Brassica oberacea var acephala leaf, and the photosynthesis of kale leaf under thallium stress was investigated by in situ attenuated total reflection FTIR (in situ ATR-FTIR). The ATR-FTIR showed that the absorption peaks of leaves had no obvious difference between plants growing in thallium stress soil and plants growing in non-thallium pollution soil, and the strong peaks at 3,380 cm(-1) could be assigned to the absorption of water, carbohydrate, protein or amide; the strong peaks at 2,916 and 2,850 cm(-1) assigned to the absorption of carbohydrate or aliphatic compound; the peaks at 1,640 cm(-1) assigned to the absorption of water. However, as detected by the in situ ATR-FTIR, the double peaks (negative peaks) at 2,360 and 2,340 cm(-1) that are assigned to the absorption of CO2 appeared and became high gradually. It was showed that kale was carrying photosynthesis. At the same time, the carbon dioxide consumption speed of leaf under thallium stress was obviously larger than that of the blank It was expressed that photosynthesis under thallium stress was stronger than the blank All these represented that kale had certain tolerance to the heavy metal thallium. Meanwhile, the carbon dioxide consumption of grown-up leaf was more than that of young leaf whether or not under thallium stress. It was also indicated that the intensity of photosynthesis in grown-up leaf is higher than that in young leaf.

  11. The effects of strawberry tree water leaf extract, arbutin and hydroquinone on haematological parameters and levels of primary DNA damage in white blood cells of rats.

    Science.gov (United States)

    Jurica, Karlo; Brčić Karačonji, Irena; Kopjar, Nevenka; Shek-Vugrovečki, Ana; Cikač, Tihana; Benković, Vesna

    2018-04-06

    Strawberry tree (Arbutus unedo L., Ericaceae) leaves represent a potent source of biologically active compounds and have been used for a long to relieve symptoms of various health impairments and diseases. Two major compounds related to their beneficial activities in animals and humans are arbutin and hydroquinone. To establish potential benefit/risk ratio associated with daily oral administration of strawberry tree water leaf extract, arbutin and hydroquinone in doses expected to be non-toxic. We performed a 14-day and a 28-day study on male and female Lewis rats and evaluated main haematological parameters and the effects of treatments on the levels of primary DNA damage in white blood cells (WBC) using the alkaline comet assay. Our findings suggest no significant changes in the haematological parameters following prolonged exposure to strawberry tree water leaf extract, arbutin, and hydroquinone. However, hydroquinone causes increased, and extract as well as arbutin decreased WBC count in male rats compared to control after 14 days of treatment. DNA damage measured in WBC of rats treated with all compounds was below 10% of the DNA in the comet tail, which indicates low genotoxicity. The genotoxic potential of strawberry water leaf extract was within acceptable limits and reflected effects of a complex chemical composition upon DNA. We also observed slight gender- and exposure time- related differences in primary DNA damage in the leucocytes of control and treated rats. Future studies should investigate which doses of strawberry tree water leaf extract would be most promising for the potential use as a substitute for bearberry leaves for treatment of urinary infection. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Transcriptional analyses of natural leaf senescence in maize.

    Directory of Open Access Journals (Sweden)

    Wei Yang Zhang

    Full Text Available Leaf senescence is an important biological process that contributes to grain yield in crops. To study the molecular mechanisms underlying natural leaf senescence, we harvested three different developmental ear leaves of maize, mature leaves (ML, early senescent leaves (ESL, and later senescent leaves (LSL, and analyzed transcriptional changes using RNA-sequencing. Three sets of data, ESL vs. ML, LSL vs. ML, and LSL vs. ESL, were compared, respectively. In total, 4,552 genes were identified as differentially expressed. Functional classification placed these genes into 18 categories including protein metabolism, transporters, and signal transduction. At the early stage of leaf senescence, genes involved in aromatic amino acids (AAAs biosynthetic process and transport, cellular polysaccharide biosynthetic process, and the cell wall macromolecule catabolic process, were up-regulated. Whereas, genes involved in amino acid metabolism, transport, apoptosis, and response to stimulus were up-regulated at the late stage of leaf senescence. Further analyses reveals that the transport-related genes at the early stage of leaf senescence potentially take part in enzyme and amino acid transport and the genes upregulated at the late stage are involved in sugar transport, indicating nutrient recycling mainly takes place at the late stage of leaf senescence. Comparison between the data of natural leaf senescence in this study and previously reported data for Arabidopsis implies that the mechanisms of leaf senescence in maize are basically similar to those in Arabidopsis. A comparison of natural and induced leaf senescence in maize was performed. Athough many basic biological processes involved in senescence occur in both types of leaf senescence, 78.07% of differentially expressed genes in natural leaf senescence were not identifiable in induced leaf senescence, suggesting that differences in gene regulatory network may exist between these two leaf senescence

  13. Parameterization of Leaf-Level Gas Exchange for Plant Functional Groups From Amazonian Seasonal Tropical Rain Forest

    Science.gov (United States)

    Domingues, T. F.; Berry, J. A.; Ometto, J. P.; Martinelli, L. A.; Ehleringer, J. R.

    2004-12-01

    Plant communities exert strong influence over the magnitude of carbon and water cycling through ecosystems by controlling photosynthetic gas exchange and respiratory processes. Leaf-level gas exchange fluxes result from a combination of physiological properties, such as carboxylation capacity, respiration rates and hydraulic conductivity, interacting with environmental drivers such as water and light availability, leaf-to-air vapor pressure deficit, and temperature. Carbon balance models concerned with ecosystem-scale responses have as a common feature the description of eco-physiological properties of vegetation. Here we focus on the parameterization of ecophysiological gas-exchange properties of plant functional groups from a pristine Amazonian seasonally dry tropical rain forest ecosystem (FLONA-Tapajós, Santarém, PA, Brazil). The parameters were specific leaf weight, leaf nitrogen content, leaf carbon isotope ratio, maximum photosynthetic assimilation rate, photosynthetic carboxylation capacity, dark respiration rates, and stomatal conductance to water vapor. Our plant functional groupings were lianas at the top of the canopy, trees at the top of the canopy, mid-canopy trees and undestory trees. Within the functional groups, we found no evidence that leaves acclimated to seasonal changes in precipitation. However, there were life-form dependent distinctions when a combination of parameters was included. Top-canopy lianas were statistically different from top-canopy trees for leaf carbon isotope ratio, maximum photosynthetic assimilation rate, and stomatal conductance to water vapor, suggesting that lianas are more conservative in the use of water, causing a stomatal limitation on photosynthetic assimilation. Top-canopy, mid canopy and understory groupings were distinct for specific leaf weight, leaf nitrogen content, leaf carbon isotope ratio, maximum photosynthetic assimilation rate, and photosynthetic carboxylation capacity. The recognition that plant

  14. Leaf optical properties with explicit description of its biochemical composition: direct and inverse problems

    Energy Technology Data Exchange (ETDEWEB)

    Fourty, T. [INRA, Avignon (France); Baret, F.; Jacquemoud, S.; Schmuck, G.; Verdebout, J.

    1996-05-15

    This study presents a methodology to estimate the leaf biochemical compounds specific absorption coefficients and to use them to predict leaf biochemistry. A wide range of leaves was collected including variations in species and leaf status. All the leaves were dried out. The biochemical composition was measured using classical wet chemistry techniques to determine lignin, cellulose, hemicellulose, starch, and protein contents. Concurrently, leaf reflectance and transmittance were measured with a high spectral resolution spectrophotometer in the 800–2500 nm range with approximately 1 nm spectral resolution and sampling interval. In addition, infinite reflectance achieved by stacking leaves was also measured. The PROSPECT leaf optical properties model was first inverted over a selection of wavebands in the 800–2400 nm domain to provide estimates of the scattering characteristics using leaf reflectance, transmittance, and infinite reflectance data. Then, the model was inverted again over all the wavelengths to estimate the global absorption coefficient, using the previously estimated scattering properties. The global absorption coefficient was eventually explained using the measured biochemical composition by fitting the corresponding specific absorption coefficients after substraction of the measured contribution of the residual structural water absorption. Results show that the derived specific absorption coefficients are quite robustly estimated. Further, they are in good agreement with known absorption features of each biochemical compound. The average contribution of each biochemical compound to leaf absorption feature is also evaluated. Sugar, cellulose, and hemicellulose are the main compounds that contribute to absorption. Results demonstrate the possibility of modeling leaf optical properties of dry leaves with explicit description of leaf biochemistry. Estimates of the detailed biochemical composition obtained by model inversion over the 1300–2400 nm

  15. Relating Stomatal Conductance to Leaf Functional Traits.

    Science.gov (United States)

    Kröber, Wenzel; Plath, Isa; Heklau, Heike; Bruelheide, Helge

    2015-10-12

    Leaf functional traits are important because they reflect physiological functions, such as transpiration and carbon assimilation. In particular, morphological leaf traits have the potential to summarize plants strategies in terms of water use efficiency, growth pattern and nutrient use. The leaf economics spectrum (LES) is a recognized framework in functional plant ecology and reflects a gradient of increasing specific leaf area (SLA), leaf nitrogen, phosphorus and cation content, and decreasing leaf dry matter content (LDMC) and carbon nitrogen ratio (CN). The LES describes different strategies ranging from that of short-lived leaves with high photosynthetic capacity per leaf mass to long-lived leaves with low mass-based carbon assimilation rates. However, traits that are not included in the LES might provide additional information on the species' physiology, such as those related to stomatal control. Protocols are presented for a wide range of leaf functional traits, including traits of the LES, but also traits that are independent of the LES. In particular, a new method is introduced that relates the plants' regulatory behavior in stomatal conductance to vapor pressure deficit. The resulting parameters of stomatal regulation can then be compared to the LES and other plant functional traits. The results show that functional leaf traits of the LES were also valid predictors for the parameters of stomatal regulation. For example, leaf carbon concentration was positively related to the vapor pressure deficit (vpd) at the point of inflection and the maximum of the conductance-vpd curve. However, traits that are not included in the LES added information in explaining parameters of stomatal control: the vpd at the point of inflection of the conductance-vpd curve was lower for species with higher stomatal density and higher stomatal index. Overall, stomata and vein traits were more powerful predictors for explaining stomatal regulation than traits used in the LES.

  16. Tree differences in primary and secondary growth drive convergent scaling in leaf area to sapwood area across Europe.

    Science.gov (United States)

    Petit, Giai; von Arx, Georg; Kiorapostolou, Natasa; Lechthaler, Silvia; Prendin, Angela Luisa; Anfodillo, Tommaso; Caldeira, Maria C; Cochard, Hervé; Copini, Paul; Crivellaro, Alan; Delzon, Sylvain; Gebauer, Roman; Gričar, Jožica; Grönholm, Leila; Hölttä, Teemu; Jyske, Tuula; Lavrič, Martina; Lintunen, Anna; Lobo-do-Vale, Raquel; Peltoniemi, Mikko; Peters, Richard L; Robert, Elisabeth M R; Roig Juan, Sílvia; Senfeldr, Martin; Steppe, Kathy; Urban, Josef; Van Camp, Janne; Sterck, Frank

    2018-06-01

    Trees scale leaf (A L ) and xylem (A X ) areas to couple leaf transpiration and carbon gain with xylem water transport. Some species are known to acclimate in A L  : A X balance in response to climate conditions, but whether trees of different species acclimate in A L  : A X in similar ways over their entire (continental) distributions is unknown. We analyzed the species and climate effects on the scaling of A L vs A X in branches of conifers (Pinus sylvestris, Picea abies) and broadleaved (Betula pendula, Populus tremula) sampled across a continental wide transect in Europe. Along the branch axis, A L and A X change in equal proportion (isometric scaling: b ˜ 1) as for trees. Branches of similar length converged in the scaling of A L vs A X with an exponent of b = 0.58 across European climates irrespective of species. Branches of slow-growing trees from Northern and Southern regions preferentially allocated into new leaf rather than xylem area, with older xylem rings contributing to maintaining total xylem conductivity. In conclusion, trees in contrasting climates adjust their functional balance between water transport and leaf transpiration by maintaining biomass allocation to leaves, and adjusting their growth rate and xylem production to maintain xylem conductance. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  17. Juvenile tree growth correlates with photosynthesis and leaf phosphorus content in central Amazonia

    Directory of Open Access Journals (Sweden)

    Ricardo Antonio Marenco

    2015-04-01

    Full Text Available Light and soil water availability may limit carbon uptake of trees in tropical rainforests. The objective of this work was to determine how photosynthetic traits of juvenile trees respond to variations in rainfall seasonality, leaf nutrient content, and opening of the forest canopy. The correlation between leaf nutrient content and annual growth rate of saplings was also assessed. In a terra firme rainforest of the central Amazon, leaf nutrient content and gas exchange parameters were measured in five sapling tree species in the dry and rainy season of 2008. Sapling growth was measured in 2008 and 2009. Rainfall seasonality led to variations in soil water content, but it did not affect leaf gas exchange parameters. Subtle changes in the canopy opening affected CO2 saturated photosynthesis (A pot, p = 0.04. Although A pot was affected by leaf nutrient content (as follows: P > Mg > Ca > N > K, the relative growth rate of saplings correlated solely with leaf P content (r = 0.52, p = 0.003. At present, reduction in soil water content during the dry season does not seem to be strong enough to cause any effect on photosynthesis of saplings in central Amazonia. This study shows that leaf P content is positively correlated with sapling growth in the central Amazon. Therefore, the positive effect of atmospheric CO2 fertilization on long-term tree growth will depend on the ability of trees to absorb additional amount of P

  18. (238)U and total radioactivity in drinking waters in Van province, Turkey.

    Science.gov (United States)

    Selçuk Zorer, Özlem; Dağ, Beşir

    2014-06-01

    As part of the national survey to evaluate natural radioactivity in the environment, concentration levels of total radioactivity and natural uranium have been analysed in drinking water samples. A survey to study natural radioactivity in drinking waters was carried out in the Van province, East Turkey. Twenty-three samples of drinking water were collected in the Van province and analysed for total α, total β and (238)U activity. The total α and total β activities were counted by using the α/β counter of the multi-detector low background system (PIC MPC-9604), and the (238)U concentrations were determined by inductively coupled plasma-mass spectrometry (Thermo Scientific Element 2). The samples were categorised according to origin: tap, spring or mineral supply. The activity concentrations for total α were found to range from 0.002 to 0.030 Bq L(-1) and for total β from 0.023 to 1.351 Bq L(-1). Uranium concentrations ranging from 0.562 to 14.710 μg L(-1) were observed in drinking waters. Following the World Health Organisation rules, all investigated waters can be used as drinking water.

  19. A finger leaf design for dual layer MLCs

    International Nuclear Information System (INIS)

    Cui Weijie; Dai Jianrong

    2010-01-01

    Objective: To introduce a finger leaf design that is applied to dual layer MLCs. Methods: An optimization model was firstly constructed to describe the problem of determining leaf end shapes,and the corresponding problems were then solved by the simplex search method or the simulated annealing technique. Optimal parameters for arc shapes of leaf end projections were obtained, and a comparison was done between optimized MLCs and conventional MLCs in terms of field conformity. The optimization process was based on 634 target fields selected from the patient data base of a treatment planning system. Areas of these fields ranged from 20.0 to 602.7 cm with a mean and its standard deviation of (125.7 ± 0.0) cm 2 . Results: The optimized leaf end shapes projected to the isocenter plane were semicircles. With the finger leaf design, the total area of discrepancy regions between MLC fields and target fields was reduced by 32.3%. Conclusions: The finger leaf design improves the conformity of the MLC shaped fields to the desired target fields. (authors)

  20. Faba Bean Can Adapt to Chocolate Spot Disease by Pretreatment with Shikimic and Salicylic Acids through Osmotic Adjustment, Solutes Allocation and Leaf Turgidity

    Directory of Open Access Journals (Sweden)

    Heshmat S. Aldesuquy

    2014-03-01

    Full Text Available This study investigated the effect of shikimic and salicylic acids at the concentrations of 0.4 and 0.7 mM, respectively, or their combination as phenolic compounds and Ridomil MZ at the concentration of 250 g/100 L as a fungicide on osmotic pressure (OP, solutes allocation, organic acids, inorganic ions and relative water content were quantified in Vicia faba leaves infected by Botrytis fabae. Pathogen induced noticeable decrease in osmotic pressure, total soluble sugar (TSS and inorganic osmolytes (i.e. Na+, K+, Ca2+, Mg2+ and Cl- while caused obvious increase in proline, total soluble nitrogen (TSN and organic acids (i.e. Keto and citric acids in water extract of the leaf of faba bean plants. Furthermore, pathogen caused marked decrease in relative water content (RWC of infected leaves and as a consequence the saturation water deficit (SWD was increased. Exogenous application of shikimic acid, salicylic acid or their combination could counteract the adverse effects of B. fabae on osmotic adjustment by inducing additional increase in proline, total soluble sugars, total soluble nitrogen and organic acids which in turn increase the osmotic pressure as well as relative water content in leaves of infected plants. Recovery of osmotic adjustment as well as leaf turgidity of infected host by using these chemical inducers may encourage the using of them as protective control means. The results of the present study showed also that the application of chemical inducers such as shikimic and salicylic acids or their interaction increased the resistance of Vicia faba against the chocolate spot disease.

  1. Calcium Ion Removal by KMnO4 Modified Pineapple Leaf Waste Carbon Prepared from Waste of Pineapple Leaf Fiber Production Processing

    Directory of Open Access Journals (Sweden)

    Sumrit Mopoung

    2016-12-01

    Full Text Available Pineapple leaf fiber waste carbon, modified with 3% KMnO4, was used for Ca2+ removal from aqueous solution. The effects of contact time, loading, water hardness, and isotherms on Ca2+ adsorption were studied. The results show that the Ca2+ ion removal by pineapple leaf fiber waste carbon could be improved by modification with KMnO4. The adsorption would reach equilibrium state at about 60 min for a water source with hardness values of 40-200 mg/dm3. Increases in total hardness (40 to 200 mg/dm3 lead to a decrease in Ca2+ ion removal efficiency (90.05% to 37.65% and an increase in Ca2+ ion adsorption capacity at equilibrium (4.37 mg/g to 8.95 mg/g. The Ca2+ removal efficiencies increase with increasing loading of modified waste carbon. The equilibrium data were fitted well by both the Langmuir isotherm and the Freundlich isotherm. For the Langmuir isotherm model, the values of the maximum Ca2+ adsorption capacity and Langmuir constant being 2.81 mg/g and 0.9262 dm3 /g, respectively. On the other hand for the Freundlich isotherm model, the KF and n values are 1.374 dm3 (1/n mg (1-1/n/g and 4.671, respectively. These results indicate that modified pineapple fiber waste carbon is a material with high Ca2+ ion adsorption capacity, heterogeneity, and high affinity.

  2. within plant resistance to water flow in tomato and sweet melons

    African Journals Online (AJOL)

    Administrator

    high pressure flow meter (HPFM) and evaporative flux (EF) methods. In the evaporative flux method, measure- ments of transpiration flux and leaf water potential were used to calculate the total resistance to water flow using. Ohm's law analogy. Measurements of tranpiration flux (Q) relationship, plant resistance calculated ...

  3. Leaf-to-branch scaling of C-gain in field-grown almond trees under different soil moisture regimes.

    Science.gov (United States)

    Egea, Gregorio; González-Real, María M; Martin-Gorriz, Bernardo; Baille, Alain

    2014-06-01

    Branch/tree-level measurements of carbon (C)-acquisition provide an integration of the physical and biological processes driving the C gain of all individual leaves. Most research dealing with the interacting effects of high-irradiance environments and soil-induced water stress on the C-gain of fruit tree species has focused on leaf-level measurements. The C-gain of both sun-exposed leaves and branches of adult almond trees growing in a semi-arid climate was investigated to determine the respective costs of structural and biochemical/physiological protective mechanisms involved in the behaviour at branch scale. Measurements were performed on well-watered (fully irrigated, FI) and drought-stressed (deficit irrigated, DI) trees. Leaf-to-branch scaling for net CO2 assimilation was quantified by a global scaling factor (fg), defined as the product of two specific scaling factors: (i) a structural scaling factor (fs), determined under well-watered conditions, mainly involving leaf mutual shading; and (ii) a water stress scaling factor (fws,b) involving the limitations in C-acquisition due to soil water deficit. The contribution of structural mechanisms to limiting branch net C-gain was high (mean fs ∼0.33) and close to the projected-to-total leaf area ratio of almond branches (ε = 0.31), while the contribution of water stress mechanisms was moderate (mean fws,b ∼0.85), thus supplying an fg ranging between 0.25 and 0.33 with slightly higher values for FI trees with respect to DI trees. These results suggest that the almond tree (a drought-tolerant species) has acquired mechanisms of defensive strategy (survival) mainly based on a specific branch architectural design. This strategy allows the potential for C-gain to be preserved at branch scale under a large range of soil water deficits. In other words, almond tree branches exhibit an architecture that is suboptimal for C-acquisition under well-watered conditions, but remarkably efficient to counteract the impact

  4. Total flavonoid and phenolic contents of n-butanol extract of Samanea saman leaf and the antibacterial activity towards Escherichia coli and Staphylococcus aureus

    Science.gov (United States)

    Rita, Wiwik Susanah; Swantara, I. Made Dira; Asih, I. A. Raka Astiti; Sinarsih, Ni Ketut; Suteja, I. Kadek Pater

    2016-03-01

    Total flavonoid and phenolic contents in some natural products was suspected of having a positive correlation to its activity in inhibiting the growth of bacteria. The aim of this study was to determine the total flavonoid and phenolic contents of n-butanol extract of Samanea saman leaf, and to evaluate the antibacterial activity towards Escherechia coli and Staphylococcus aureus. Extraction of compounds was done by ethanol 96%, followed by fractionation into n-hexane, ethyl acetate, and n-butanol. Determination of total flavonoid and phenolic contents was done by UV-Vis Spectrophotometer using standard of quersetin and galic acid respectively. In addition, antibacterial activity was evaluated by agar disc diffusion method. Extraction of 1000 g of Samanea saman leaf was obtained 80 g of ethanol extracts, fractionation of the extract was obtained 8.02 g of n-hexane extracts, 7.11 g of ethyl acetate extracts, 13.5 g of n-butanol extracts, and 14.16 g of aqueous extracts. Phytochemical screening of the n-butanol extracts revealed the presence of flavonoid and phenolic compounds. Total flavonoid and phenolic contents were successively 43.5798 mg QE/100g and 34.0180 mg GAE/100g. The butanol extracts inhibited the growth of S.aureus higher than the growth of E.coli. At the concentration of 2, 4, 6, 8 % (b/v), and positive control (meropenem μg/disc), inhibition zone towards S. aureus was successively 5.67, 9.33, 10.33, 12.00, and 32.33 mm, while the inhibition zone towards E. coli was1.33, 3.33, 4.33, 5.43, and 34.00 mm.

  5. Effects of wind and simulated acid mist on leaf cuticles

    International Nuclear Information System (INIS)

    Hoad, S.P.; Jeffree, C.E.; Grace, J.

    1994-01-01

    The combined effect of wind and simulated acid mist on leaf cuticles was investigated in beech (Fagus sylvatica L.) and birch (Betula pubescens Ehr.). Macroscopic and microscopic features of wind damage are described. Visibly damaged leaf area and the numbers of microscopic cuticular lesions were measured. The cuticular conductance to water vapour (g c ) of the astomatous adaxial surfaces of the leaves was measured by a gravimetric method. Field experimenntal sites were selected to provide either: 1. Direct wind action on widely-spaced plants caused by high speed and impaction of wind-blown particles, but with minimal mutual leaf abrasion 2. Indirect wind action via a high degree of mutual abrasion between closely-spaced plants. Direct wind action increased water loss via the leaf adaxial cuticle two- to three-fold in each species, by increasing the numbers of microscopic cuticular lesions. Indirect wind action caused more visible damage to leaves than direct wind action, increased g c by about threefold compared with complete shelter, and induced the most cuticular lesions. Acid mists at pH 3 or pH 5 were applied to the plants in situ at weekly intervals over a 100-day period. In sheltered plants, no effect of acid mist was detected on visibly damaged leaf area, the numbers of microscopic cuticular lesions, or on g c . However, acid mists in combination with wind exposure caused significant effects on cuticular integrity that were dependent on the type of wind action. Direct wind action combined with pH 3 acid mist resulted in the largest numbers of microscopic cuticular lesions, and the highest g c . By contrast, indirect wind action combined with pH 3 acid mist caused most visible damage to leaf tissue, but fewer microscopic lesions, and lower g c , than in plants treated with water mist. In severely-abraded leaves exposed to indirect wind action and low-pH acid rain, g c may be reduced by wound-isolation of blocks of non-functional leaf tissue. (orig.)

  6. Inverse gradients in leaf wax δD and δ13C values along grass blades of Miscanthus sinensis: implications for leaf wax reproduction and plant physiology.

    Science.gov (United States)

    Gao, Li; Huang, Yongsong

    2013-06-01

    Compound specific hydrogen and carbon isotopic ratios of higher plant leaf waxes have been extensively used in paleoclimate and paleoenvironmental reconstructions. However, studies so far have focused on the comparison of leaf wax isotopic differences in bulk leaf samples between different plant species. We sampled three different varieties of tall grasses (Miscanthus sinensis) in six segments from base to tip and determined hydrogen and carbon isotopic ratios of leaf waxes, as well as hydrogen and oxygen isotopic ratios of leaf water samples. We found an increasing, base-to-tip hydrogen isotopic gradient along the grass blades that can probably be attributed to active leaf wax regeneration over the growth season. Carbon isotopic ratios, on the other hand, show opposite trends to hydrogen isotopic ratios along the grass blades, which may reflect different photosynthetic efficiencies at different blade locales.

  7. Leaf physico-chemical and physiological properties of maize (Zea mays L.) populations from different origins.

    Science.gov (United States)

    Revilla, Pedro; Fernández, Victoria; Álvarez-Iglesias, Lorena; Medina, Eva T; Cavero, José

    2016-10-01

    In this study we evaluated the leaf surface properties of maize populations native to different water availability environments. Leaf surface topography, wettability and gas exchange performance of five maize populations from the Sahara desert, dry (south) and humid (north-western) areas of Spain were analysed. Differences in wettability, stomatal and trichome densities, surface free energy and solubility parameter values were recorded between populations and leaf sides. Leaves from the humid Spanish population with special regard to the abaxial side, were less wettable and less susceptible to polar interactions. The higher wettability and hydrophilicity of Sahara populations with emphasis on the abaxial leaf surfaces, may favour dew deposition and foliar water absorption, hence improving water use efficiency under extremely dry conditions. Compared to the other Saharan populations, the dwarf one had a higher photosynthesis rate suggesting that dwarfism may be a strategy for improving plant tolerance to arid conditions. The results obtained for different maize populations suggest that leaf surfaces may vary in response to drought, but further studies will be required to examine the potential relationship between leaf surface properties and plant stress tolerance. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  8. Within plant resistance to water flow in tomato and sweet melons ...

    African Journals Online (AJOL)

    In the evaporative flux method, measurements of transpiration flux and leaf water potential were used to calculate the total resistance to water flow using Ohm's law analogy. Measurements of tranpiration flux (Q) relationship, plant resistance calculated from the slope of their relationship, ranged from 6.57x10-01 to ...

  9. Leaf turgor loss point is correlated with drought tolerance and leaf carbon economics traits.

    Science.gov (United States)

    Zhu, Shi-Dan; Chen, Ya-Jun; Ye, Qing; He, Peng-Cheng; Liu, Hui; Li, Rong-Hua; Fu, Pei-Li; Jiang, Guo-Feng; Cao, Kun-Fang

    2018-05-01

    Leaf turgor loss point (πtlp) indicates the capacity of a plant to maintain cell turgor pressure during dehydration, which has been proven to be strongly predictive of the plant response to drought. In this study, we compiled a data set of πtlp for 1752 woody plant individuals belonging to 389 species from nine major woody biomes in China, along with reduced sample size of hydraulic and leaf carbon economics data. We aimed to investigate the variation of πtlp across biomes varying in water availability. We also tested two hypotheses: (i) πtlp predicts leaf hydraulic safety margins and (ii) it is correlated with leaf carbon economics traits. Our results showed that there was a positive relationship between πtlp and aridity index: biomes from humid regions had less negative values than those from arid regions. This supports the idea that πtlp may reflect drought tolerance at the scale of woody biomes. As expected, πtlp was significantly positively correlated with leaf hydraulic safety margins that varied significantly across biomes, indicating that this trait may be useful in modelling changes of forest components in response to increasing drought. Moreover, πtlp was correlated with a suite of coordinated hydraulic and economics traits; therefore, it can be used to predict the position of a given species along the 'fast-slow' whole-plant economics spectrum. This study expands our understanding of the biological significance of πtlp not only in drought tolerance, but also in the plant economics spectrum.

  10. Dependence of fluence errors in dynamic IMRT on leaf-positional errors varying with time and leaf number

    International Nuclear Information System (INIS)

    Zygmanski, Piotr; Kung, Jong H.; Jiang, Steve B.; Chin, Lee

    2003-01-01

    ALPO is an Average Leaf Pair Opening (the concept of ALPO was previously introduced by us in Med. Phys. 28, 2220-2226 (2001). Therefore, dose errors associated with RLP errors are larger for fields requiring small leaf gaps. For an N-field IMRT plan, we demonstrate that the total fluence error (if we neglect inhomogeneities and scatter) is proportional to 1/√(N), where N is the number of fields, which slightly reduces the impact of RLP errors of individual fields on the total fluence error. We tested and applied the analytical apparatus in the context of commercial inverse treatment planning systems used in our clinics (Helios TM and BrainScan TM ). We determined the actual distribution of leaf-positional errors by studying MLC controller (Varian Mark II and Brainlab Novalis MLCs) log files created by the controller after each field delivery. The analytically derived relationship between fluence error and RLP errors was confirmed by numerical simulations. The equivalence of relative fluence error to relative dose error was verified by a direct dose calculation. We also experimentally verified the truthfulness of fluences derived from the log file data by comparing them to film data

  11. Fagus sylvatica L. provenances maintain different leaf metabolic profiles and functional response

    Science.gov (United States)

    Aranda, Ismael; Sánchez-Gómez, David; de Miguel, Marina; Mancha, Jose Antonio; Guevara, María Angeles; Cadahía, Estrella; Fernández de Simón, María Brígida

    2017-07-01

    Most temperate forest tree species will suffer important environmental changes as result of the climate change. Adaptiveness to local conditions could change at different sites in the future. In this context, the study of intra-specific variability is important to clarify the singularity of different local populations. Phenotypic differentiation between three beech provenances covering a wide latitudinal range (Spain/ES, Germany/DE and Sweden/SE), was studied in a greenhouse experiment. Non-target leaf metabolite profiles and ecophysiological response was analyzed in well-watered and water stressed seedlings. There was a provenance-specific pattern in the relative concentrations of some leaf metabolites regardless watering treatment. The DE and SE from the center and north of the distribution area of the species showed a clear differentiation from the ES provenance in the relative concentration of some metabolites. Thus the ES provenance from the south maintained larger relative concentration of some organic and amino acids (e.g. fumaric and succinic acids or valine and isoleucine), and in some secondary metabolites (e.g. kaempferol, caffeic and ferulic acids). The ecophysiological response to mild water stress was similar among the three provenances as a consequence of the moderate water stress applied to seedlings, although leaf N isotope composition (δ15N) and leaf C:N ratio were higher and lower respectively in DE than in the other two provenances. This would suggest potential differences in the capacity to uptake and post-process nitrogen according to provenance. An important focus of the study was to address for the first time inter-provenance leaf metabolic diversity in beech from a non-targeted metabolic profiling approach that allowed differentiation of the three studied provenances.

  12. An evolutionary attractor model for sapwood cross section in relation to leaf area.

    Science.gov (United States)

    Westoby, Mark; Cornwell, William K; Falster, Daniel S

    2012-06-21

    Sapwood cross-sectional area per unit leaf area (SA:LA) is an influential trait that plants coordinate with physical environment and with other traits. We develop theory for SA:LA and also for root surface area per leaf area (RA:LA) on the premise that plants maximizing the surplus of revenue over costs should have competitive advantage. SA:LA is predicted to increase in water-relations environments that reduce photosynthetic revenue, including low soil water potential, high water vapor pressure deficit (VPD), and low atmospheric CO(2). Because sapwood has costs, SA:LA adjustment does not completely offset difficult water relations. Where sapwood costs are large, as in tall plants, optimal SA:LA may actually decline with (say) high VPD. Large soil-to-root resistance caps the benefits that can be obtained from increasing SA:LA. Where a plant can adjust water-absorbing surface area of root per leaf area (RA:LA) as well as SA:LA, optimal RA:SA is not affected by VPD, CO(2) or plant height. If selection favours increased height more so than increased revenue-minus-cost, then height is predicted to rise substantially under improved water-relations environments such as high-CO(2) atmospheres. Evolutionary-attractor theory for SA:LA and RA:LA complements models that take whole-plant conductivity per leaf area as a parameter. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Water relation, leaf gas exchange and chlorophyll a fluorescence imaging of soybean leaves infected with Colletotrichum truncatum.

    Science.gov (United States)

    Dias, Carla Silva; Araujo, Leonardo; Alves Chaves, Joicy Aparecida; DaMatta, Fábio M; Rodrigues, Fabrício A

    2018-06-01

    Considering the potential of anthracnose to decrease soybean yield and the need to gain more information regarding its effect on soybean physiology, the present study performed an in-depth analysis of the photosynthetic performance of soybean leaflets challenged with Colletotrichum truncatum by combining chlorophyll a fluorescence images with gas-exchange measurements and photosynthetic pigment pools. There were no significant differences between non-inoculated and inoculated plants in leaf water potential, apparent hydraulic conductance, net CO 2 assimilation rate, stomatal conductance to water vapor and transpiration rate. For internal CO 2 concentration, significant difference between non-inoculated and inoculated plants occurred only at 36 h after inoculation. Reductions in the values of the chlorophyll a fluorescence parameters [initial fluorescence (F 0 ), maximal fluorescence (F m ), maximal photosystem II quantum yield (F v /F m ), quantum yield of regulated energy dissipation (Y(NPQ))] and increases in effective PS II quantum yield (Y(II)), quantum yield of non-regulated energy dissipation Y(NO) and photochemical quenching coefficient (q P ) were noticed on the necrotic vein tissue in contrast to the surrounding leaf tissue. It appears that the impact of the infection by C. truncatum on the photosynthetic performance of the leaflets was minimal considering the preference of the fungus to colonize the veins. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  14. Using a Chlorophyll Meter to Evaluate the Nitrogen Leaf Content in Flue-Cured Tobacco (Nicotiana tabacum L.

    Directory of Open Access Journals (Sweden)

    Fabio Castelli

    2009-06-01

    Full Text Available In flue-cured tobacco N fertilizer is commonly applied during pre-planting, and very often applied again later as a growth-starter. It is generally held that the efficiency of N-fertilizer use can be improved by evaluating the leaf Nstatus after transplanting and until flowering stage. N use efficiency in this context does not refer merely to the yield but also to the quality, in the meanwhile minimizing the negative effects on the environment. To investigate these aspects, we evaluated the capacity of a Minolta model SPAD-502 chlorophyll meter to estimate the N-status in flue-cured tobacco. The aims was to verify if a relationship exists between SPAD readings and leaf N content, and if a single leaf, in a well defined stalk position, could represent the nitrogen content of the whole plant. During the years 1995 and 1996, a pot experiment was conducted using two flue-cured tobacco varieties. SPAD values, total chlorophyll, total N contents and leaf area were measured throughout the growing season, on each odd leaf stalk position. SPAD values were well-correlated with both total chlorophyll and total N leaf concentration, and the regression coefficients were higher when relationships were calculated on a leaf-area basis. For both relationships, SPAD-total chlorophyll and SPAD-total N, the best fittings were obtained with quadratic equations. One leaf stalk position alone is able to monitor the N-status of the whole plant during the first six weeks after transplanting, without distinction of year and variety effects. The SPAD measurement of one leaf per plant, throughout the vegetative growing season, is therefore a valid tool to test the N-status of the crop in a period when a required N supply is still effective.

  15. Effect of urdbean leaf crinkle virus infection on total soluble protein and antioxidant enzymes in blackgram plants

    International Nuclear Information System (INIS)

    Ashfaq, M.; Mughal, S.M.; Khan, A.; Javed, N.; Sahi, S.T.; Shahid, M.

    2010-01-01

    Urdbean leaf crinkle virus (ULCV) is a common, wide spread, destructive and economically important disease causing systemic infection in blackgram (Vigna mungo (L.) Hepper), resulting in extreme crinkling, curling, puckering and rugosity of leaves, and yield reductions. Effect of viral infection was investigated on total soluble proteins and antioxidant enzymes activity in two genotypes viz., Mash-88-susceptible and CM-2002-resistant, at different growth stages under both the inoculated and un-inoculated conditions. ULCV infection resulted in significant increase in total soluble protein contents of the leaves in both genotypes. In healthy plant, super oxide dismutase (SOD), catalase (CAT) and peroxidase (PO) showed similar activity levels. In inoculated plants of Mash-88, SOD and PO activities decreased and increased non-significantly at all growth stages, respectively. The activities of PO and SOD increased and decreased significantly after 15 and 30 days of inoculation in resistant genotype, respectively. No significant changes in catalase (CAT) activity were detected in ULCV-infected leaves over the control. It was concluded that the super oxide dismutase and peroxidases might be associated with resistance/susceptibility to ULCV infection. (author)

  16. A New Method to Quantify the Isotopic Signature of Leaf Transpiration: Implications for Landscape-Scale Evapotranspiration Partitioning Studies

    Science.gov (United States)

    Wang, L.; Good, S. P.; Caylor, K. K.

    2010-12-01

    Characterizing the constituent components of evapotranspiration is crucial to better understand ecosystem-level water budgets and water use dynamics. Isotope based evapotranspiration partitioning methods are promising but their utility lies in the accurate estimation of the isotopic composition of underlying transpiration and evaporation. Here we report a new method to quantify the isotopic signature of leaf transpiration under field conditions. This method utilizes a commercially available laser-based isotope analyzer and a transparent leaf chamber, modified from Licor conifer leaf chamber. The method is based on the water mass balance in ambient air and leaf transpired air. We verified the method using “artificial leaves” and glassline extracted samples. The method provides a new and direct way to estimate leaf transpiration isotopic signatures and it has wide applications in ecology, hydrology and plant physiology.

  17. Maize YABBY genes drooping leaf1 and drooping leaf2 affect agronomic traits by regulating leaf architecture

    Science.gov (United States)

    Leaf architectural traits, such as length, width and angle, directly influence canopy structure and light penetration, photosynthate production and overall yield. We discovered and characterized a maize (Zea mays) mutant with aberrant leaf architecture we named drooping leaf1 (drl1), as leaf blades ...

  18. The effect of electron collimator leaf shape on the build-up dose in narrow electron MLC fields

    International Nuclear Information System (INIS)

    Vatanen, T; Vaeaenaenen, A; Lahtinen, T; Traneus, E

    2009-01-01

    Previously, we have found that the build-up dose from abutting narrow electron beams formed with unfocussed electron multi-leaf collimator (eMLC) steal leaves was higher than with the respective open field. To investigate more closely the effect of leaf material and shape on dose in the build-up region, straight, round (radius 1.5 cm) and leaf ends with a different front face angle of α (leaf front face pointing towards the beam axis at an angle of 90 - α) made of steel, brass and tungsten were modelled using the BEAMnrc code. Based on a treatment head simulation of a Varian 2100 C/D linac, depth-dose curves and profiles in water were calculated for narrow 6, 12 and 20 MeV eMLC beams (width 1.0 cm, length 10 cm) at source-to-surface distances (SSD) of 102 and 105 cm. The effects of leaf material and front face angle were evaluated based on electron fluence, angle and energy spectra. With a leaf front face angle of 15 deg., the dose in the build-up region of the 6 MeV field varied between 91 and 100%, while for straight and round leaf shapes the dose varied between 89 and 100%. The variation was between 94 and 100% for 12 and 20 MeV. For abutting narrow 6 MeV fields with total field size 5 x 10 cm 2 , the build-up doses at 5 mm depth for the face angle 15 deg. and straight and round leaf shapes were 96% and 86% (SSD 102 cm) and 89% and 85% (SSD 105 cm). With higher energies, the effect of eMLC leaf shape on dose at 5 mm was slight (3-4% units with 12 MeV) and marginal with 20 MeV. The fluence, energy and angle spectra for total and leaf scattered electrons were practically the same for different leaf materials with 6 MeV. With high energies, the spectra for tungsten were more peaked due to lower leaf transmission. Compared with straight leaf ends, the face angle of 15 deg. and round leaf ends led to a 1 mm (for 6 MeV) and between 1 and 5 mm (12 and 20 MeV at a SSD of 105 cm) decrease of therapeutic range and increase of the field size, respectively. However

  19. Leaf structural characteristics are less important than leaf chemical properties in determining the response of leaf mass per area and photosynthesis of Eucalyptus saligna to industrial-age changes in [CO2] and temperature.

    Science.gov (United States)

    Xu, Cheng-Yuan; Salih, Anya; Ghannoum, Oula; Tissue, David T

    2012-10-01

    The rise in atmospheric [CO(2)] is associated with increasing air temperature. However, studies on plant responses to interactive effects of [CO(2)] and temperature are limited, particularly for leaf structural attributes. In this study, Eucalyptus saligna plants were grown in sun-lit glasshouses differing in [CO(2)] (290, 400, and 650 µmol mol(-1)) and temperature (26 °C and 30 °C). Leaf anatomy and chloroplast parameters were assessed with three-dimensional confocal microscopy, and the interactive effects of [CO(2)] and temperature were quantified. The relative influence of leaf structural attributes and chemical properties on the variation of leaf mass per area (LMA) and photosynthesis within these climate regimes was also determined. Leaf thickness and mesophyll size increased in higher [CO(2)] but decreased at the warmer temperature; no treatment interaction was observed. In pre-industrial [CO(2)], warming reduced chloroplast diameter without altering chloroplast number per cell, but the opposite pattern (reduced chloroplast number per cell and unchanged chloroplast diameter) was observed in both current and projected [CO(2)]. The variation of LMA was primarily explained by total non-structural carbohydrate (TNC) concentration rather than leaf thickness. Leaf photosynthetic capacity (light- and [CO(2)]-saturated rate at 28 °C) and light-saturated photosynthesis (under growth [CO(2)] and temperature) were primarily determined by leaf nitrogen contents, while secondarily affected by chloroplast gas exchange surface area and chloroplast number per cell, respectively. In conclusion, leaf structural attributes are less important than TNC and nitrogen in affecting LMA and photosynthesis responses to the studied climate regimes, indicating that leaf structural attributes have limited capacity to adjust these functional traits in a changing climate.

  20. Root morphology, hydraulic conductivity and plant water relations of high-yielding rice grown under aerobic conditions.

    Science.gov (United States)

    Kato, Yoichiro; Okami, Midori

    2011-09-01

    Increasing physical water scarcity is a major constraint for irrigated rice (Oryza sativa) production. 'Aerobic rice culture' aims to maximize yield per unit water input by growing plants in aerobic soil without flooding or puddling. The objective was to determine (a) the effect of water management on root morphology and hydraulic conductance, and (b) their roles in plant-water relationships and stomatal conductance in aerobic culture. Root system development, stomatal conductance (g(s)) and leaf water potential (Ψ(leaf)) were monitored in a high-yielding rice cultivar ('Takanari') under flooded and aerobic conditions at two soil moisture levels [nearly saturated (> -10 kPa) and mildly dry (> -30 kPa)] over 2 years. In an ancillary pot experiment, whole-plant hydraulic conductivity (soil-leaf hydraulic conductance; K(pa)) was measured under flooded and aerobic conditions. Adventitious root emergence and lateral root proliferation were restricted even under nearly saturated conditions, resulting in a 72-85 % reduction in total root length under aerobic culture conditions. Because of their reduced rooting size, plants grown under aerobic conditions tended to have lower K(pa) than plants grown under flooded conditions. Ψ(leaf) was always significantly lower in aerobic culture than in flooded culture, while g(s) was unchanged when the soil moisture was at around field capacity. g(s) was inevitably reduced when the soil water potential at 20-cm depth reached -20 kPa. Unstable performance of rice in water-saving cultivations is often associated with reduction in Ψ(leaf). Ψ(leaf) may reduce even if K(pa) is not significantly changed, but the lower Ψ(leaf) would certainly occur in case K(pa) reduces as a result of lower water-uptake capacity under aerobic conditions. Rice performance in aerobic culture might be improved through genetic manipulation that promotes lateral root branching and rhizogenesis as well as deep rooting.

  1. Water relations and microclimate around the upper limit of a cloud forest in Maui, Hawai'i.

    Science.gov (United States)

    Gotsch, Sybil G; Crausbay, Shelley D; Giambelluca, Thomas W; Weintraub, Alexis E; Longman, Ryan J; Asbjornsen, Heidi; Hotchkiss, Sara C; Dawson, Todd E

    2014-07-01

    The goal of this study was to determine the effects of atmospheric demand on both plant water relations and daily whole-tree water balance across the upper limit of a cloud forest at the mean base height of the trade wind inversion in the tropical trade wind belt. We measured the microclimate and water relations (sap flow, water potential, stomatal conductance, pressure-volume relations) of Metrosideros polymorpha Gaudich. var. polymorpha in three habitats bracketing the cloud forest's upper limit in Hawai'i to understand the role of water relations in determining ecotone position. The subalpine shrubland site, located 100 m above the cloud forest boundary, had the highest vapor pressure deficit, the least amount of rainfall and the highest levels of nighttime transpiration (EN) of all three sites. In the shrubland site, on average, 29% of daily whole-tree transpiration occurred at night, while on the driest day of the study 50% of total daily transpiration occurred at night. While EN occurred in the cloud forest habitat, the proportion of total daily transpiration that occurred at night was much lower (4%). The average leaf water potential (Ψleaf) was above the water potential at the turgor loss point (ΨTLP) on both sides of the ecotone due to strong stomatal regulation. While stomatal closure maintained a high Ψleaf, the minimum leaf water potential (Ψleafmin) was close to ΨTLP, indicating that drier conditions may cause drought stress in these habitats and may be an important driver of current landscape patterns in stand density. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Water-deficit tolerant classification in mutant lines of indica rice

    Directory of Open Access Journals (Sweden)

    Suriyan Cha-um

    2012-04-01

    Full Text Available Water shortage is a major abiotic stress for crop production worldwide, limiting the productivity of crop species, especially in dry-land agricultural areas. This investigation aimed to classify the water-deficit tolerance in mutant rice (Oryza sativa L. spp. indica genotypes during the reproductive stage. Proline content in the flag leaf of mutant lines increased when plants were subjected to water deficit. Relative water content (RWC in the flag leaf of different mutant lines dropped in relation to water deficit stress. A decrease RWC was positively related to chlorophyll a degradation. Chlorophyll a , chlorophyll b , total chlorophyll , total carotenoids , maximum quantum yield of PSII , stomatal conductance , transpiration rate and water use efficiency in mutant lines grown under water deficit conditions declined in comparison to the well-watered, leading to a reduction in net-photosynthetic rate. In addition, when exposed to water deficit, panicle traits, including panicle length and fertile grains were dropped. The biochemical and physiological data were subjected to classify the water deficit tolerance. NSG19 (positive control and DD14 were identified as water deficit tolerant, and AA11, AA12, AA16, BB13, BB16, CC12, CC15, EE12, FF15, FF17, G11 and IR20 (negative control as water deficit sensitive, using Ward's method.

  3. Variation in the carbon and oxygen isotope composition of plant biomass and its relationship to water-use efficiency at the leaf- and ecosystem-scales in a northern Great Plains grassland.

    Science.gov (United States)

    Flanagan, Lawrence B; Farquhar, Graham D

    2014-02-01

    Measurements of the carbon (δ(13) Cm ) and oxygen (δ(18) Om ) isotope composition of C3 plant tissue provide important insights into controls on water-use efficiency. We investigated the causes of seasonal and inter-annual variability in water-use efficiency in a grassland near Lethbridge, Canada using stable isotope (leaf-scale) and eddy covariance measurements (ecosystem-scale). The positive relationship between δ(13) Cm and δ(18) Om values for samples collected during 1998-2001 indicated that variation in stomatal conductance and water stress-induced changes in the degree of stomatal limitation of net photosynthesis were the major controls on variation in δ(13) Cm and biomass production during this time. By comparison, the lack of a significant relationship between δ(13) Cm and δ(18) Om values during 2002, 2003 and 2006 demonstrated that water stress was not a significant limitation on photosynthesis and biomass production in these years. Water-use efficiency was higher in 2000 than 1999, consistent with expectations because of greater stomatal limitation of photosynthesis and lower leaf ci /ca during the drier conditions of 2000. Calculated values of leaf-scale water-use efficiency were 2-3 times higher than ecosystem-scale water-use efficiency, a difference that was likely due to carbon lost in root respiration and water lost during soil evaporation that was not accounted for by the stable isotope measurements. © 2013 John Wiley & Sons Ltd.

  4. Water Quality Assessment and Total Maximum Daily Loads Information (ATTAINS)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Water Quality Assessment TMDL Tracking And Implementation System (ATTAINS) stores and tracks state water quality assessment decisions, Total Maximum Daily Loads...

  5. Effects of leaf hair points of a desert moss on water retention and dew formation: implications for desiccation tolerance.

    Science.gov (United States)

    Tao, Ye; Zhang, Yuan Ming

    2012-05-01

    Leaf hair points (LHPs) are important morphological structures in many desiccation-tolerant mosses, but study of their functions has been limited. A desert moss, Syntrichia caninervis, was chosen for examination of the ecological effects of LHPs on water retention and dew formation at individual and population (patch) levels. Although LHPs were only 4.77% of shoot weight, they were able to increase absolute water content (AWC) by 24.87%. The AWC of samples with LHPs was always greater than for those without LHPs during dehydration. The accumulative evaporation ratio (AER) showed an opposite trend. AWC, evaporation ratio and AER of shoots with LHPs took 20 min longer to reach a completely dehydrated state than shoots without LHPs. At the population level, dew formation on moss crusts with LHPs was faster than on crusts without LHPs, and the former had higher daily and total dew amounts. LHPs were able to improve dew amounts on crusts by 10.26%. Following three simulated rainfall events (1, 3 and 6 mm), AERs from crusts with LHPs were always lower than from crusts without LHPs. LHPs can therefore significantly delay and reduce evaporation. We confirm that LHPs are important desiccation-tolerant features of S. caninervis at both individual and population levels. LHPs greatly aid moss crusts in adapting to arid conditions.

  6. Leaf photosynthetic traits scale with hydraulic conductivity and wood density in Panamanian forest canopy trees.

    Science.gov (United States)

    L.S. Santiago; G. Goldstein; F.C. Meinzer; J.B. Fisher; K. Maehado; D. Woodruff; T. Jones

    2004-01-01

    We investigated how water transport capacity, wood density and wood anatomy were related to leaf photosynthetic traits in two lowland forests in Panama. Leaf-specific hydraulic conductivity (kL) of upper branches was positively correlated with maximum rates of net CO2, assimilation per unit leaf area (Aarea...

  7. Oxygen isotope analysis of plant water without extraction procedure

    International Nuclear Information System (INIS)

    Gan, K.S.; Wong, S.C.; Farquhar, G.D.; Yong, J.W.H.

    2001-01-01

    Isotopic analyses of plant water (mainly xylem, phloem and leaf water) are gaming importance as the isotopic signals reflect plant-environment interactions, affect the oxygen isotopic composition of atmospheric O 2 and CO 2 and are eventually incorporated into plant organic matter. Conventionally, such isotopic measurements require a time-consuming process of isolating the plant water by azeotropic distillation or vacuum extraction, which would not complement the speed of isotope analysis provided by continuous-flow IRMS (Isotope-Ratio Mass Spectrometry), especially when large data sets are needed for statistical calculations in biological studies. Further, a substantial amount of plant material is needed for water extraction and leaf samples would invariably include unenriched water from the fine veins. To measure sub-microlitre amount of leaf mesophyll water, a new approach is undertaken where a small disc of fresh leaf is cut using a specially designed leaf punch, and pyrolysed directly in an IRMS. By comparing with results from pyrolysis of the dry matter of the same leaf, the 18 O content of leaf water can be determined without extraction from fresh leaves. This method is validated using a range of cellulose-water mixtures to simulate the constituents of fresh leaf. Cotton leaf water δ 18 O obtained from both methods of fresh leaf pyrolysis and azeotropic distillation will be compared. The pyrolysis technique provides a robust approach to measure the isotopic content of water or any volatile present in a homogeneous solution or solid hydrous substance

  8. Comparison of total body water determinations in lactating women by anthropometry, water displacement, and deuterium isotope dilution

    International Nuclear Information System (INIS)

    Wong, W.; Butte, N.; Lee, L.; Garza, C.; Klein, P.

    1986-01-01

    To expand the limited data on the total body water in lactating women, the authors have determined total body water contents, in eight subjects from anthropometric measurements, water displacement, and isotope dilution of deuterium oxide. On the day of the study, their skinfold thicknesses were measured over the biceps and triceps muscles and at the suprailiac and subscapular areas. Their body densities were measured by water displacement. Deuterium oxide was administered orally at 100 mg/kg of body weight. One predose milk sample was collected from each subject. The milk samples were defatted by centrifugation and the milk water was reduced to hydrogen gas for hydrogen isotope ratio measurements by gas-isotope-ratio mass spectrometry. The results indicated that total body water in lactating women estimated from anthropometric measurements was 49.7 +/- 3.3% of body weight, by water displacement was 54.9 +/- 7.2%, and by isotope dilution was 50.8 +/- 3.7%

  9. The Stimulation Effects of N+ Ion Beam on Liquorice and Its Influence on Water Stress

    International Nuclear Information System (INIS)

    Wei Shenglin; Liu Jingnan; Wu Lijun; Wang Jiabao; Yu Zengliang

    2006-01-01

    We have developed a large number of exocrine glands on liquorice leaves and facilitated polysaccharide secretion. Liquorice polysaccharide possesses stronger bound water affinity to gaseous water compared with sucrose and glucose. Our results show that the bound water affinity of liquorice polysaccharide to gaseous water is 49.75% higher than glucose (p + implantation (total dosage of 4.68x10 16 ions/cm 2 and energy of 20 keV) into dry liquorice seeds, both the bound water affinity to gaseous water and the bound water content of dry liquorice leaf can be significantly increased 30.24% ( p + implantation into dry liquorice seeds, the leaf polysaccharide content under water stress (ψ w = -1.5 MPa) can increase significantly (p<0.05) and the plant growth can also improve significantly (p<0.05)

  10. Determination of the total indicative dose in drinking and mineral waters

    International Nuclear Information System (INIS)

    Flesch, K.; Schulz, H.; Knappik, R.; Koehler, M.

    2006-01-01

    In Europe and Germany administrative regulations exist for the surveillance of the total indicative dose of water supplied for human consumption. This parameter, which cannot be analyzed directly, has to be calculated using nuclide specific activity concentration and age specific dose conversion factors and consumption rates. Available calculation methods differ regarding the used radionuclides, consumption rates and whether they use age specific dose conversion factors or not. In Germany administrative guidelines for the determination of the total indicative dose are still not available. As they have analyzed a large number of waters in the past, the authors derive a praxis orientated concept for the determination of the total indicative dose which respects radiological, analytical and hydrochemical aspects as well. Finally it is suggested to handle sparkling waters in the same manner as drinking waters. (orig.)

  11. Ozone Flux Measurement and Modelling on Leaf/Shoot and Canopy Scale

    Directory of Open Access Journals (Sweden)

    Ludger Grünhage

    Full Text Available The quantitative study of the ozone effects on agricultural and forest vegetation requires the knowledge of the pollutant dose absorbed by plants via leaf stomata, i.e. the stomatal flux. Nevertheless, the toxicologically effective dose can differ from the stomatal flux because a pool of scavenging and detoxification processes reduce the amount of pollutant responsible of the expression of the harmful effects. The measurement of the stomatal flux is not immediate and the quantification of the effective dose is still troublesome. The paper examines the conceptual aspects of ozone flux measurement and modelling in agricultural and ecological research. The ozone flux paradigm is conceptualized into a toxicological frame and faced at two different scales: leaf/shoot and canopy scales. Leaf and shoot scale flux measurements require gas-exchange enclosure techniques, while canopy scale flux measurements need a micrometeorological approach including techniques such as eddy covariance and the aerodynamical gradient. At both scales, not all the measured ozone flux is stomatal flux. In fact, a not negligible amount of ozone is destroyed on external plant surfaces, like leaf cuticles, or by gas phase reaction with biogenic volatile compounds. The stomatal portion of flux can be calculated from concurrent measurements of water vapour fluxes at both scales. Canopy level flux measurements require very fast sensors and the fulfilment of many conditions to ensure that the measurements made above the canopy really reflect the canopy fluxes (constant flux hypothesis. Again, adjustments are necessary in order to correct for air density fluctuations and sensor-surface alignment break. As far as regards flux modelling, at leaf level the stomatal flux is simply obtained by multiplying the ozone concentration on the leaf with the stomatal conductance predicted by means of physiological models fed by meteorological parameter. At canopy level the stomatal flux is

  12. Gauging leaf-level contributions to landscape-level water loss within a Western US dryland fores

    Science.gov (United States)

    Murphy, P.; Potts, D. L.; Minor, R. L.; Hamerlynck, E. P.; Sutter, L., Jr.; Barron-Gafford, G.

    2017-12-01

    Western US forests represent a large constituent of the North American water and carbon cycles, yet the primary controls on water loss from these ecosystems remains unknown. In dryland forests, such as those found in the Southwestern US, water availability is key to ecosystem function, and the timing and magnitude of water loss can have lasting effects on the health of these communities. One poorly defined part of the water balance in these forests is the partitioning of evapotranspiration (ET) into evaporation (E; blue flow) to transpiration (T; green flow). A study of water fluxes at multiple scales in a semiarid montane forest in Southern Arizona speaks to the partitioning of these two water flows. Within the footprint of an eddy covariance system, which estimates ecosystem ET, we have examined the impacts of variation in climate, species makeup, and topographic position on E and T. This was done using leaf-level measures of T, pedon-scale measures of E, and whole-tree water loss by way of sap flux sensors. Where available, we have examined E, T, and ET fluxes across multiple seasons and years of highly variable precipitation records. Understanding the partitioning of ET is crucial, considering that projected changes to dryland ecosystems include longer periods of drought separated by heavier precipitation events. At a moment when potential impacts of changing climate on dryland structure and function are poorly understood, a stronger comprehension of these blue and green water flows is necessary to forecast the productivity of Western US forests into the future.

  13. Interspecific variations in mangrove leaf litter decomposition are related to labile nitrogenous compounds

    Science.gov (United States)

    Nordhaus, Inga; Salewski, Tabea; Jennerjahn, Tim C.

    2017-06-01

    Mangrove leaves form a large pool of carbon, nitrogen and energy that is a major driver of element cycles and detrital food webs inside mangrove forests as well as in adjacent coastal waters. However, there are large gaps in knowledge on the transformation pathways and ultimate fate of leaf nitrogen. Therefore, the main objective of this study was to determine the amount and composition of nitrogenous organic matter and possible species-specific differences during the decomposition of mangrove leaf litter. For that purpose a three month decomposition experiment with litterbags was conducted using leaves of Aegiceras corniculatum, Avicennia alba, Ceriops decandra, Rhizophora apiculata, and Sonneratia caseolaris in the mangrove forest of the Segara Anakan Lagoon, Java, Indonesia. Detrital leaves were analyzed for bulk carbon and total nitrogen (N), stable carbon and nitrogen isotope composition (δ13C, δ15N), total hydrolyzable amino acids (THAA) and total hydrolyzable hexosamines (THHA). Decomposition rates (k d-1) were highest and tM50 values (when 50% of the original mass had been degraded) lowest in S. caseolaris (k = 0.0382 d-1; tM50 = 18 days), followed by A. alba, C. decandra, A. corniculatum, and R. apiculata (k = 0.0098 d-1; tM50 = 71 days). The biochemical composition of detrital leaves differed significantly among species and over time. S. caseolaris and A. alba had higher concentrations of N, THAA and THHA and a lower C/N ratio than the other three species. For most of the species concentrations of N, THAA and THHA increased during decomposition. The hexosamine galactosamine, indicative of bacterial cell walls, was first found in leaves after 5-7 days of decomposition and increased afterwards. Our findings suggest an increasing, but species-specific varying, portion of labile nitrogenous OM and total N in decomposing leaves over time that is partly related to the activity of leaf-colonizing bacteria. Despite a higher relative nitrogen content in the

  14. Leaf Surface Effects on Retrieving Chlorophyll Content from Hyperspectral Remote Sensing

    Science.gov (United States)

    Qiu, Feng; Chen, JingMing; Ju, Weimin; Wang, Jun; Zhang, Qian

    2017-04-01

    Light reflected directly from the leaf surface without entering the surface layer is not influenced by leaf internal biochemical content. Leaf surface reflectance varies from leaf to leaf due to differences in the surface roughness features and is relatively more important in strong absorption spectral regions. Therefore it introduces dispersion of data points in the relationship between biochemical concentration and reflectance (especially in the visible region). Separation of surface from total leaf reflection is important to improve the link between leaf pigments content and remote sensing data. This study aims to estimate leaf surface reflectance from hyperspectral remote sensing data and retrieve chlorophyll content by inverting a modified PROSPECT model. Considering leaf surface reflectance is almost the same in the visible and near infrared spectral regions, a surface layer with a reflectance independent of wavelength but varying from leaf to leaf was added to the PROSPECT model. The specific absorption coefficients of pigments were recalibrated. Then the modified model was inverted on independent datasets to check the performance of the model in predicting the chlorophyll content. Results show that differences in estimated surface layer reflectance of various species are noticeable. Surface reflectance of leaves with epicuticular waxes and trichomes is usually higher than other samples. Reconstruction of leaf reflectance and transmittance in the 400-1000 nm wavelength region using the modified PROSPECT model is excellent with low root mean square error (RMSE) and bias. Improvements for samples with high surface reflectance (e.g. maize) are significant, especially for high pigment leaves. Moreover, chlorophyll retrieved from inversion of the modified model is consequently improved (RMSE from 5.9-13.3 ug/cm2 with mean value 8.1 ug/cm2, while mean correlation coefficient is 0.90) compared to results of PROSPECT-5 (RMSE from 9.6-20.2 ug/cm2 with mean value 13

  15. Impact of Vertical Canopy Position on Leaf Spectral Properties and Traits across Multiple Species

    Directory of Open Access Journals (Sweden)

    Tawanda W. Gara

    2018-02-01

    Full Text Available Understanding the vertical pattern of leaf traits across plant canopies provide critical information on plant physiology, ecosystem functioning and structure and vegetation response to climate change. However, the impact of vertical canopy position on leaf spectral properties and subsequently leaf traits across the entire spectrum for multiple species is poorly understood. In this study, we examined the ability of leaf optical properties to track variability in leaf traits across the vertical canopy profile using Partial Least Square Discriminatory Analysis (PLS-DA. Leaf spectral measurements together with leaf traits (nitrogen, carbon, chlorophyll, equivalent water thickness and specific leaf area were studied at three vertical canopy positions along the plant stem: lower, middle and upper. We observed that foliar nitrogen (N, chlorophyll (Cab, carbon (C, and equivalent water thickness (EWT were higher in the upper canopy leaves compared with lower shaded leaves, while specific leaf area (SLA increased from upper to lower canopy leaves. We found that leaf spectral reflectance significantly (P ≤ 0.05 shifted to longer wavelengths in the ‘red edge’ spectrum (685–701 nm in the order of lower > middle > upper for the pooled dataset. We report that spectral bands that are influential in the discrimination of leaf samples into the three groups of canopy position, based on the PLS-DA variable importance projection (VIP score, match with wavelength regions of foliar traits observed to vary across the canopy vertical profile. This observation demonstrated that both leaf traits and leaf reflectance co-vary across the vertical canopy profile in multiple species. We conclude that canopy vertical position has a significant impact on leaf spectral properties of an individual plant’s traits, and this finding holds for multiple species. These findings have important implications on field sampling protocols, upscaling leaf traits to canopy level

  16. Evaluating water deficit and glyphosate treatment on the accumulation of phenolic compounds and photosynthesis rate in transgenic Codonopsis lanceolata (Siebold & Zucc.) Trautv. over-expressing γ-tocopherol methyltransferase (γ-tmt) gene.

    Science.gov (United States)

    Ghimire, Bimal Kumar; Son, Na-Young; Kim, Seung-Hyun; Yu, Chang Yeon; Chung, Ill-Min

    2017-07-01

    The effect of water stress and herbicide treatment on the phenolic compound concentration and photosynthesis rate in transgenic Codonopsis lanceolata plants over-expressing the γ-tmt gene was investigated and compared to that in control non-transgenic C. lanceolata plants. The total phenolic compound content was investigated using high-performance liquid chromatography combined with diode array detection in C. lanceolata seedlings 3 weeks after water stress and treatment with glyphosate. Changes in the composition of phenolic compounds were observed in leaf and root extracts from transformed C. lanceolata plants following water stress and treatment with glyphosate. The total concentration of phenolic compounds in the leaf extracts of transgenic samples after water stress ranged from 3455.13 ± 40.48 to 8695.00 ± 45.44 µg g -1 dry weight (DW), whereas the total concentration phenolic compound in the leaf extracts of non-transgenic control samples was 5630.83 ± 45.91 µg g -1  DW. The predominant phenolic compounds that increased after the water stress in the transgenic leaf were (+) catechin, benzoic acid, chlorogenic acid, ferulic acid, gallic acid, rutin, vanillic acid, and veratric acid. The total concentration of phenolic compounds in the leaf extracts of transgenic samples after glyphosate treatment ranged from 4744.37 ± 81.81 to 12,051.02 ± 75.00 µg g -1 DW, whereas the total concentration of the leaf extracts of non-transgenic control samples after glyphosate treatment was 3778.28 ± 59.73 µg g -1 DW. Major phenolic compounds that increased in the transgenic C. lanceolata plants after glyphosate treatment included kaempherol, gallic acid, myricetin, p-hydroxybenzjoic acid, quercetin, salicylic acid, t-cinnamic acid, catechin, benzoicacid, ferulic acid, protocatechuic acid, veratric acid, and vanillic acid. Among these, vanillic acid showed the greatest increase in both leaf and root extracts from transgenic plants relative to

  17. Relationship of leaf oxygen and carbon isotopic composition with transpiration efficiency in the C4 grasses Setaria viridis and Setaria italica.

    Science.gov (United States)

    Ellsworth, Patrick Z; Ellsworth, Patrícia V; Cousins, Asaph B

    2017-06-15

    Leaf carbon and oxygen isotope ratios can potentially provide a time-integrated proxy for stomatal conductance (gs) and transpiration rate (E), and can be used to estimate transpiration efficiency (TE). In this study, we found significant relationships of bulk leaf carbon isotopic signature (δ13CBL) and bulk leaf oxygen enrichment above source water (Δ18OBL) with gas exchange and TE in the model C4 grasses Setaria viridis and S. italica. Leaf δ13C had strong relationships with E, gs, water use, biomass, and TE. Additionally, the consistent difference in δ13CBL between well-watered and water-limited plants suggests that δ13CBL is effective in separating C4 plants with different availability of water. Alternatively, the use of Δ18OBL as a proxy for E and TE in S. viridis and S. italica was problematic. First, the oxygen isotopic composition of source water, used to calculate leaf water enrichment (Δ18OLW), was variable with time and differed across water treatments. Second, water limitations changed leaf size and masked the relationship of Δ18OLW and Δ18OBL with E. Therefore, the data collected here suggest that δ13CBL but not Δ18OBL may be an effective proxy for TE in C4 grasses. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  18. Leaf movement, photosynthesis and resource use efficiency responses to multiple environmental stress in Glycine max (soybean)

    International Nuclear Information System (INIS)

    Rosa, L.M.G.

    1993-01-01

    Increases in the concentration of greenhouse gases in the atmosphere, may cause a significant increase in temperature, with implications for general wind patterns and precipitation. Reductions in stratospheric ozone will result in increased levels of UV-B reaching earth's surface. During their lifetime plants must deal with a variety of co-occurring environmental stresses. Accordingly, studies into plant responses to multiple environmental factors is important to our understanding of limits to their growth, productivity, and distribution. Heliotropic leaf movements are a generalized plant response to environmental stresses, and the pattern of these movements can be altered by resource availability (e.g., water, and nitrogen). Previous greenhouse and field studies have demonstrated damaging effects of UV-B radiation in crop species, including soybean. Documented in this paper are Leaf movement and gas exchange responses of four soybean cultivars with different sensitivity to UV-B radiation to enhanced levels of UV-B, and modifications of these responses caused by water stress and nitrogen fertilization. UV-B radiation had no effect on the patterns of leaf orientation in soybean; however, a ranking of the cultivars based on midday leaf angles was the same as the ranking of these cultivars based on their sensitivity to UV-B radiation. Water and nitrogen altered the leaf movement patterns of soybeans. Gas exchange parameters in all four cultivars responded in a similar fashion to changes in leaf water potential. Reductions in water availability resulted in lower discrimination. Nitrogen fertilization in cv Forrest, also resulted in lower discrimination, especially under low water regimes, indicating a higher water use efficiency for fertilized plants. UV-B radiation resulted in lower discrimination in the UV-B sensitive CNS cultivar, indicating a stronger stomatal limitation to photosynthesis under increased UV-B levels

  19. Evaluating a tobacco leaf humidification system involving nebulisation

    Directory of Open Access Journals (Sweden)

    Néstor Enrique Cerquera Peña

    2010-05-01

    Full Text Available A tobacco leaf humidifying system involving nebulisation was designned, implemented and evaluated; it had a system for monitoring and recording environmental conditions thereby producing an environment having more homogeneous relative humidity, ensuring better water use, better control of relative humidity and better control in managing cured tobacco leaf moisture content, thereby leading to a consequent improvement in final product quality. 55% to 75% relative humidity and 4 to 6 hour working ranges were obtained to en- sure leaf humidification reached 16% humidity on a wet basis. Two new designs are proposed for the conditioning stage regarding this conditioning chamber’s operational management, based on the results and field observations, which would allow better leaf management, thereby avoiding the risk of losses due to manipulation and over-humidification. This work strengthens research in the field of tobacco pos- tharvest technology, complementing other research projects which have been carried out in Colombia.

  20. CAMEX-4 DC-8 NEVZOROV TOTAL CONDENSED WATER CONTENT SENSOR V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The CAMEX-4 DC-8 Nevzorov Total Condensed Water Content Sensor dataset was collected by the Nevzorov total condensed water content sensor which was used to measure...

  1. Evaluation of Microdesmis puberula leaf meal as feed ingredient in ...

    African Journals Online (AJOL)

    The material was milled using a hammer mill to produce the leaf meal. Microdesmis puberula leaf meal contain 17.32% crude protein, 6.52% ether extract, 12.25% total ash, 24.84% crude fibre, 24.06% NFE and an appreciable percent of minerals. Three broiler starter diets were formulated to contain the meal at dietary ...

  2. Water-borne hyphomycetes in tree canopies of Kaiga (Western Ghats, India

    Directory of Open Access Journals (Sweden)

    Naga M. Sudheep

    2013-12-01

    Full Text Available The canopy samples such as trapped leaf litter, trapped sediment (during summer, stemflow and throughfall (during monsoon from five common riparian tree species (Artocarpus heterophyllus, Cassia fistula, Ficus recemosa, Syzygium caryophyllatum and Xylia xylocarpa in Kaiga forest stand of the Western Ghats of southwest India were evaluated for the occurrence of water-borne hyphomycetes. Partially decomposed trapped leaf litter was incubated in bubble chambers followed by filtration to assess conidial output. Sediments accumulated in tree holes or junction of branches were shaken with sterile leaf disks in distilled water followed by incubation of leaf disks in bubble chamber and filtration to find out colonized fungi. Stemflow and throughfall samples were filtered directly to collect free conidia. From five canopy niches, a total of 29 water-borne hyphomycetes were recovered. The species richness was higher in stemflow and throughfall than trapped leaf litter and sediments (14-16 vs. 6-10 species. Although sediments of Syzygium caryophyllatum were acidic (5.1, the conidial output was higher than other tree species. Stemflow and throughfall of Xylea xylocarpa even though alkaline (8.5-8.7 showed higher species richness (6-12 species as well as conidial load than rest of the tree species. Flagellospora curvula and Triscelophorus acuminatus were common in trapped leaf litter and sediments respectively, while conidia of Anguillospora crassa and A. longissima were frequent in stemflow and throughfall. Diversity of water-borne hyphomycetes was highest in throughfall of Xylea xylocarpa followed by throughfall of Ficus recemosa. Our study reconfirms the occurrence and survival of diverse water-borne hyphomycetes in different niches of riparian tree canopies of the Western Ghats during wet and dry regimes and predicts their possible role in canopy as saprophytes, endophytes and alternation of life cycle between canopy and aquatic habitats.

  3. Optimal allocation of leaf epidermal area for gas exchange

    OpenAIRE

    de Boer, Hugo J.; Price, Charles A.; Wagner-Cremer, Friederike; Dekker, Stefan C.; Franks, Peter J.; Veneklaas, Erik J.

    2016-01-01

    Summary A long?standing research focus in phytology has been to understand how plants allocate leaf epidermal space to stomata in order to achieve an economic balance between the plant's carbon needs and water use. Here, we present a quantitative theoretical framework to predict allometric relationships between morphological stomatal traits in relation to leaf gas exchange and the required allocation of epidermal area to stomata. Our theoretical framework was derived from first principles of ...

  4. Tamarix and Diorhabda leaf beetle interactions: implications for Tamarix water use and riparian habitat

    Science.gov (United States)

    Nagler, Pamela; Glenn, Edward P.

    2013-01-01

    Tamarix leaf beetles (Diorhabda carinulata) have been widely released on western United States rivers to control introduced shrubs in the genus Tamarix, with the goals of saving water through removal of an assumed high water-use plant, and of improving habitat value by removing a competitor of native riparian trees. We review recent studies addressing three questions: (1) to what extent are Tamarix weakened or killed by recurrent cycles of defoliation; (2) can significant water salvage be expected from defoliation; and (3) what are the effects of defoliation on riparian ecology, particularly on avian habit? Defoliation has been patchy at many sites, and shrubs at some sites recover each year even after multiple years of defoliation. Tamarix evapotranspiration (ET) is much lower than originally assumed in estimates of potential water savings, and are the same or lower than possible replacement plants. There is concern that the endangered southwestern willow flycatcher (Empidonax trailli extimus) will be negatively affected by defoliation because the birds build nests early in the season when Tamarix is still green, but are still on their nests during the period of summer defoliation. Affected river systems will require continued monitoring and development of adaptive management practices to maintain or enhance riparian habitat values. Multiplatform remote sensing methods are playing an essential role in monitoring defoliation and rates of ET on affected river systems.

  5. Extraction of antioxidant pigments from dye sorghum leaf sheaths

    NARCIS (Netherlands)

    Kayode, A.P.P.; Bara, C.A.; Dalode-Vieira, G.; Linnemann, A.R.; Nout, M.J.R.

    2012-01-01

    Extraction of antioxidant biocolorant pigments from leaf sheaths of dye sorghum was optimized. Effects of temperature and ethanol concentration of the extraction solvent on the concentrations of the 3-deoxyanthocyanidins, total phenolics and total anthocyanins, and the colour parameters of the

  6. A Two-Big-Leaf Model for Canopy Temperature, Photosynthesis, and Stomatal Conductance.

    Science.gov (United States)

    Dai, Yongjiu; Dickinson, Robert E.; Wang, Ying-Ping

    2004-06-01

    The energy exchange, evapotranspiration, and carbon exchange by plant canopies depend on leaf stomatal control. The treatment of this control has been required by land components of climate and carbon models. Physiological models can be used to simulate the responses of stomatal conductance to changes in atmospheric and soil environments. Big-leaf models that treat a canopy as a single leaf tend to overestimate fluxes of CO2 and water vapor. Models that differentiate between sunlit and shaded leaves largely overcome these problems.A one-layered, two-big-leaf submodel for photosynthesis, stomatal conductance, leaf temperature, and energy fluxes is presented in this paper. It includes 1) an improved two stream approximation model of radiation transfer of the canopy, with attention to singularities in its solution and with separate integrations of radiation absorption by sunlit and shaded fractions of canopy; 2) a photosynthesis stomatal conductance model for sunlit and shaded leaves separately, and for the simultaneous transfers of CO2 and water vapor into and out of the leaf—leaf physiological properties (i.e., leaf nitrogen concentration, maximum potential electron transport rate, and hence photosynthetic capacity) vary throughout the plant canopy in response to the radiation weight time-mean profile of photosynthetically active radiation (PAR), and the soil water limitation is applied to both maximum rates of leaf carbon uptake by Rubisco and electron transport, and the model scales up from leaf to canopy separately for all sunlit and shaded leaves; 3) a well-built quasi-Newton Raphson method for simultaneous solution of temperatures of the sunlit and shaded leaves.The model was incorporated into the Common Land Model (CLM) and is denoted CLM 2L. It was driven with observational atmospheric forcing from two forest sites [Anglo-Brazilian Amazonian Climate Observation Study (ABRACOS) and Boreal Ecosystem Atmosphere Study (BOREAS)] for 2 yr of simulation. The

  7. Persisting soil drought reduces leaf specific conductivity in Scots pine (Pinus sylvestris) and pubescent oak (Quercus pubescens)

    NARCIS (Netherlands)

    Sterck, F.J.; Zweifel, R.; Sass-Klaassen, U.; Qumruzzaman, C.

    2008-01-01

    Summary Leaf specific conductivity (LSC; the ratio of stem conductivity (KP) to leaf area (AL)), a measure of the hydraulic capacity of the stem to supply leaves with water, varies with soil water content. Empirical evidence for LSC responses to drought is ambiguous, because previously published

  8. Genetic variation in a grapevine progeny (Vitis vinifera L. cvs Grenache×Syrah) reveals inconsistencies between maintenance of daytime leaf water potential and response of transpiration rate under drought

    Science.gov (United States)

    Coupel-Ledru, Aude; Lebon, Éric; Christophe, Angélique; Doligez, Agnès; Cabrera-Bosquet, Llorenç; Péchier, Philippe; Hamard, Philippe; This, Patrice; Simonneau, Thierry

    2014-01-01

    In the face of water stress, plants evolved with different abilities to limit the decrease in leaf water potential, notably in the daytime (ΨM). So-called isohydric species efficiently maintain high ΨM, whereas anisohydric species cannot prevent ΨM from dropping as soil water deficit develops. The genetic and physiological origins of these differences in (an)isohydric behaviours remain to be clarified. This is of particular interest within species such as Vitis vinifera L. where continuous variation in the level of isohydry has been observed among cultivars. With this objective, a 2 year experiment was conducted on the pseudo-F1 progeny from a cross between the two widespread cultivars Syrah and Grenache using a phenotyping platform coupled to a controlled-environment chamber. Potted plants of all the progeny were analysed for ΨM, transpiration rate, and soil-to-leaf hydraulic conductance, under both well-watered and water deficit conditions. A high genetic variability was found for all the above traits. Four quantitative trait loci (QTLs) were detected for ΨM under water deficit conditions, and 28 other QTLs were detected for the different traits in either condition. Genetic variation in ΨM maintenance under water deficit weakly correlated with drought-induced reduction in transpiration rate in the progeny, and QTLs for both traits did not completely co-localize. This indicates that genetic variation in the control of ΨM under water deficit was not due simply to variation in transpiration sensitivity to soil drying. Possible origins of the diversity in (an)isohydric behaviours in grapevine are discussed on the basis of concurrent variations in soil-to-leaf hydraulic conductance and stomatal control of transpiration. PMID:25381432

  9. Exogenous nitric oxide improves sugarcane growth and photosynthesis under water deficit.

    Science.gov (United States)

    Silveira, Neidiquele M; Frungillo, Lucas; Marcos, Fernanda C C; Pelegrino, Milena T; Miranda, Marcela T; Seabra, Amedea B; Salgado, Ione; Machado, Eduardo C; Ribeiro, Rafael V

    2016-07-01

    Nitric oxide (NO)-mediated redox signaling plays a role in alleviating the negative impact of water stress in sugarcane plants by improving root growth and photosynthesis. Drought is an environmental limitation affecting sugarcane growth and yield. The redox-active molecule nitric oxide (NO) is known to modulate plant responses to stressful conditions. NO may react with glutathione (GSH) to form S-nitrosoglutathione (GSNO), which is considered the main reservoir of NO in cells. Here, we investigate the role of NO in alleviating the effects of water deficit on growth and photosynthesis of sugarcane plants. Well-hydrated plants were compared to plants under drought and sprayed with mock (water) or GSNO at concentrations ranging from 10 to 1000 μM. Leaf GSNO sprayed plants showed significant improvement of relative water content and leaf and root dry matter under drought compared to mock-sprayed plants. Additionally, plants sprayed with GSNO (≥ 100 μM) showed higher leaf gas exchange and photochemical activity as compared to mock-sprayed plants under water deficit and after rehydration. Surprisingly, a raise in the total S-nitrosothiols content was observed in leaves sprayed with GSH or GSNO, suggesting a long-term role of NO-mediated responses to water deficit. Experiments with leaf discs fumigated with NO gas also suggested a role of NO in drought tolerance of sugarcane plants. Overall, our data indicate that the NO-mediated redox signaling plays a role in alleviating the negative effects of water stress in sugarcane plants by protecting the photosynthetic apparatus and improving shoot and root growth.

  10. Leaf Dynamics of Panicum maximum under Future Climatic Changes.

    Science.gov (United States)

    Britto de Assis Prado, Carlos Henrique; Haik Guedes de Camargo-Bortolin, Lívia; Castro, Érique; Martinez, Carlos Alberto

    2016-01-01

    Panicum maximum Jacq. 'Mombaça' (C4) was grown in field conditions with sufficient water and nutrients to examine the effects of warming and elevated CO2 concentrations during the winter. Plants were exposed to either the ambient temperature and regular atmospheric CO2 (Control); elevated CO2 (600 ppm, eC); canopy warming (+2°C above regular canopy temperature, eT); or elevated CO2 and canopy warming (eC+eT). The temperatures and CO2 in the field were controlled by temperature free-air controlled enhancement (T-FACE) and mini free-air CO2 enrichment (miniFACE) facilities. The most green, expanding, and expanded leaves and the highest leaf appearance rate (LAR, leaves day(-1)) and leaf elongation rate (LER, cm day(-1)) were observed under eT. Leaf area and leaf biomass were higher in the eT and eC+eT treatments. The higher LER and LAR without significant differences in the number of senescent leaves could explain why tillers had higher foliage area and leaf biomass in the eT treatment. The eC treatment had the lowest LER and the fewest expanded and green leaves, similar to Control. The inhibitory effect of eC on foliage development in winter was indicated by the fewer green, expanded, and expanding leaves under eC+eT than eT. The stimulatory and inhibitory effects of the eT and eC treatments, respectively, on foliage raised and lowered, respectively, the foliar nitrogen concentration. The inhibition of foliage by eC was confirmed by the eC treatment having the lowest leaf/stem biomass ratio and by the change in leaf biomass-area relationships from linear or exponential growth to rectangular hyperbolic growth under eC. Besides, eC+eT had a synergist effect, speeding up leaf maturation. Therefore, with sufficient water and nutrients in winter, the inhibitory effect of elevated CO2 on foliage could be partially offset by elevated temperatures and relatively high P. maximum foliage production could be achieved under future climatic change.

  11. Soil water effect on crop growth, leaf gas exchange, water and radiation use efficiency of Saccharum spontaneum L. ssp. aegyptiacum (Willd. Hackel in semi-arid Mediterranean environment

    Directory of Open Access Journals (Sweden)

    Danilo Scordia

    2015-12-01

    Full Text Available Great effort has been placed to identify the most suited bioenergy crop under different environments and management practices, however, there is still need to find new genetic resources for constrained areas. For instance, South Mediterranean area is strongly affected by prolonged drought, high vapour pressure deficit (VPD and extremely high temperatures during summertime. In the present work we investigated the soil water effect on crop growth and leaf gas exchange of Saccharum spontaneum L. ssp. aegyptiacum (Willd. Hackel, a perennial, rhizomatous, herbaceous grass. Furthermore, the net increase of biomass production per unit light intercepted [radiation use efficiency (RUE] and per unit water transpired [water use efficiency (WUE] was also studied. To this end a field trial was carried out imposing three levels of soil water availability (I100, I50 and I0, corresponding to 100%, 50% and 0% of ETm restutition under a semi-arid Mediterranean environment. Leaf area index (LAI, stem height, biomass dry matter yield, CO2 assimilation rate, and transpiration rate resulted significantly affected by measurement time and irrigation treatment, with the highest values in I100 and the lowest in I0. RUE was the highest in I100 followed by I50 and I0; on the other hand, WUE was higher in I0 than I50 and I100. At LAI values greater than 2.0, 85% photosynthetically active radiation was intercepted by the Saccharum stand, irrespective of the irrigation treatment. Saccharum spontaneum spp. aegyptiacum is a potential species for biomass production in environment characterized by drought stress, high temperatures and high VPD, as those of Southern Europe and similar semi-arid areas.

  12. Antimicrobial olive leaf gelatin films for enhancing the quality of cold smoked salmon

    Science.gov (United States)

    Olive leaf products were evaluated as antimicrobial/antioxidant ingredients in edible films for smoked fish preservation. Olive leaf powder (OLP) and its water/ethanol extract (OLE) were tested against Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella enterica using agar diffusion test...

  13. Effect of water deficit on growth and photosynthetic characteristics of ...

    African Journals Online (AJOL)

    Water deficit decreased total leaf area, above-ground biomass, net photosynthesis, stomatal conductance, internal CO2 concentration and the actual quantum yield of PS II electron transport relative to cultivars that were grown under control condition. Measurement of stomatal conductance provided useful information to ...

  14. Shrub type dominates the vertical distribution of leaf C : N : P stoichiometry across an extensive altitudinal gradient

    Directory of Open Access Journals (Sweden)

    W. Zhao

    2018-04-01

    Full Text Available Understanding leaf stoichiometric patterns is crucial for improving predictions of plant responses to environmental changes. Leaf stoichiometry of terrestrial ecosystems has been widely investigated along latitudinal and longitudinal gradients. However, very little is known about the vertical distribution of leaf C : N : P and the relative effects of environmental parameters, especially for shrubs. Here, we analyzed the shrub leaf C, N and P patterns in 125 mountainous sites over an extensive altitudinal gradient (523–4685 m on the Tibetan Plateau. Results showed that the shrub leaf C and C : N were 7.3–47.5 % higher than those of other regional and global flora, whereas the leaf N and N : P were 10.2–75.8 % lower. Leaf C increased with rising altitude and decreasing temperature, supporting the physiological acclimation mechanism that high leaf C (e.g., alpine or evergreen shrub could balance the cell osmotic pressure and resist freezing. The largest leaf N and high leaf P occurred in valley region (altitude 1500 m, likely due to the large nutrient leaching from higher elevations, faster litter decomposition and nutrient resorption ability of deciduous broadleaf shrub. Leaf N : P ratio further indicated increasing N limitation at higher altitudes. Interestingly, drought severity was the only climatic factor positively correlated with leaf N and P, which was more appropriate for evaluating the impact of water status than precipitation. Among the shrub ecosystem and functional types (alpine, subalpine, montane, valley, evergreen, deciduous, broadleaf, and conifer, their leaf element contents and responses to environments were remarkably different. Shrub type was the largest contributor to the total variations in leaf stoichiometry, while climate indirectly affected the leaf C : N : P via its interactive effects on shrub type or soil. Collectively, the large heterogeneity in shrub type was the most

  15. Genetic control and combining ability of flag leaf area and relative water content traits of bread wheat cultivars under drought stress condition

    Directory of Open Access Journals (Sweden)

    Golparvar Ahmad Reza

    2013-01-01

    Full Text Available In order to compare mode of inheritance, combining ability, heterosis and gene action in genetic control of traits flag leaf area, relative water content and grain filling rate of bread wheat under drought stress, a study was conducted on 8 cultivars using of Griffing’s method2 in fixed model. Mean square of general combining ability was significant also for all traits and mean square of specific combining ability was significant also for all traits except relative water content of leaf which show importance of both additive and dominant effects of genes in heredity of these traits under stress. GCA to SCA mean square ratio was significant for none of traits. Results of this study showed that non additive effects of genes were more important than additive effect for all traits. According to results we can understand that genetic improvement of mentioned traits will have low genetic efficiency by selection from the best crosses of early generations. Then it is better to delay selection until advanced generations and increase in heritability of these traits.

  16. The leaf size-twig size spectrum in evergreen broadleaved forest of ...

    African Journals Online (AJOL)

    Compared to deciduous broad-leaved species, the evergreen broad-leaved species were smaller in total leaf area for a given cross-sectional area or stem mass. This suggests that the species would support less leaf area at a given twig cross-sectional area with increasing environmental stress. And the life form can modify ...

  17. Sheep fed with banana leaf hay reduce ruminal protozoa population.

    Science.gov (United States)

    Freitas, Cláudio Eduardo Silva; Duarte, Eduardo Robson; Alves, Dorismar David; Martinele, Isabel; D'Agosto, Marta; Cedrola, Franciane; de Moura Freitas, Angélica Alves; Dos Santos Soares, Franklin Delano; Beltran, Makenzi

    2017-04-01

    A ciliate protozoa suppression can reduce methane production increasing the energy efficiency utilization by ruminants. The physicochemical characteristics of rumen fluid and the profile of the rumen protozoa populations were evaluated for sheep fed banana leaf hay in replacement of the Cynodon dactylon cv. vaqueiro hay. A total of 30 male sheep were raised in intensive system during 15 days of adaptation and 63 days of experimental period. The animals were distributed in a completely randomized design that included six replicates of five treatments with replacement levels (0, 25, 50, 75, and 100%) of the grass vaquero for the banana leaf hay. Samples of fluid were collected directly from the rumen with sterile catheters. Color, odor, viscosity, and the methylene blue reduction potential (MBRP) were evaluated and pH estimated using a digital potentiometer. After decimal dilutions, counts of genus protozoa were performed in Sedgewick Rafter chambers. The averages of pH, MBRP, color, odor, and viscosity were not influenced by the inclusion of the banana leaf hay. However, the total number of protozoa and Entodinium spp. population significantly decreased at 75 and 100% inclusions of banana leaf hay as roughage.

  18. Effect of Plant Growth Regulators on Leaf Number, Leaf Area and Leaf Dry Matter in Grape

    Directory of Open Access Journals (Sweden)

    Zahoor Ahmad BHAT

    2011-03-01

    Full Text Available Influence of phenylureas (CPPU and brassinosteriod (BR along with GA (gibberellic acid were studied on seedless grape vegetative characteristics like leaf number, leaf area and leaf dry matter. Growth regulators were sprayed on the vines either once (7 days after fruit set or 15 days after fruit set or twice (7+15 days after fruit set. CPPU 2 ppm+BR 0.4 ppm+GA 25 ppm produced maximum number of leaves (18.78 while as untreated vines produced least leaf number (16.22 per shoot. Maximum leaf area (129.70 cm2 and dry matter content (26.51% was obtained with higher CPPU (3 ppm and BR (0.4 ppm combination along with GA 25 ppm. Plant growth regulators whether naturally derived or synthetic are used to improve the productivity and quality of grapes. The relatively high value of grapes justifies more expensive inputs. A relatively small improvement in yield or fruit quality can justify the field application of a very costly product. Application of new generation growth regulators like brassinosteroids and phenylureas like CPPU have been reported to increase the leaf number as well as leaf area and dry matter thereby indirectly influencing the fruit yield and quality in grapes.

  19. EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2014. Scientific Opinion on the substantiation of a health claim related to olive leaf (Olea europaea L.) water extract and increase in glucose tolerance pursuant to Article 13(5) of Regulation (EC) No 1924/2006

    DEFF Research Database (Denmark)

    Tetens, Inge

    substantiation of a health claim related to olive (Olea europaea L.) leaf water extract and increase in glucose tolerance. The food that is the subject of the health claim, olive leaf water extract standardised by its content of oleuropein, is sufficiently characterised. The claimed effect, an increase...... is insufficient to establish a cause and effect relationship between the consumption of olive leaf water extract and an increase in glucose tolerance....... in glucose tolerance, is a beneficial physiological effect as long as serum insulin concentrations are not disproportionately increased. One human intervention study showed an increase in glucose tolerance without disproportionate increase in insulin concentrations after daily consumption of the olive leaf...

  20. Models for leaf area estimation in dwarf pigeon pea by leaf dimensions

    Directory of Open Access Journals (Sweden)

    Rafael Vieira Pezzini

    2018-03-01

    Full Text Available ABSTRACT This study aims to determine the most suitable model to estimate the leaf area of dwarf pigeon pea in function of the leaf central leaflet dimension. Six samplings of 200 leaves were performed in the first experiment, at 36, 42, 50, 56, 64, and 72 days after emergence (DAE. In the second experiment, seven samplings of 200 leaves were performed at 29, 36, 43, 49, 57, 65, and 70 DAE, totaling 2600 leaves. The length (L and width (W of the central leaflet were measured in all leaves composed by left, central, and right leaflets, the product of length times width (LW was calculated, and the leaf area (Y – sum of left, central, and right leaflet areas was determined by digital images. Linear, power, quadratic, and cubic models of Y as function of L, W, and LW were built using data from the second experiment. Leaves from the first experiment were used to validate the models. In dwarf pigeon pea, the linear (Ŷ = – 0.4088 + 1.6669x, R2 = 0.9790 is preferable, but power (Ŷ = 1.6097x1.0065, R2 = 0.9766, quadratic (Ŷ = – 0.3625 + 1.663x + 0.00007x2, R2 = 0.9790, and cubic (Ŷ = 0.7216 + 1.522x + 0.005x2 – 5E–05x3, R2 = 0.9791 models in function of LW are also suitable to estimate the leaf area obtained by digital images. The power model (Ŷ = 5.2508x1.7868, R2 = 0.95 based on the central leaflet width is less laborious because requires only one variable, but it presents accuracy reduction.

  1. The effect of air pollution and other environmental stressors on leaf fluctuating asymmetry and specific leaf area of Salix alba L

    Energy Technology Data Exchange (ETDEWEB)

    Wuytack, Tatiana, E-mail: tatiana.wuytack@ua.ac.be [Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Wuyts, Karen, E-mail: karen.wuyts@ugent.be [Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Laboratory of Forestry, Department of Forest and Water Management, Ghent University, Geraardsbergsesteenweg 267, B-9090 Gontrode (Melle) (Belgium); Van Dongen, Stefan, E-mail: stefan.vandongen@ua.ac.be [Department of Biology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Baeten, Lander, E-mail: lander.baeten@ugent.be [Laboratory of Forestry, Department of Forest and Water Management, Ghent University, Geraardsbergsesteenweg 267, B-9090 Gontrode (Melle) (Belgium); Kardel, Fatemeh, E-mail: fatemeh.kardel@ua.ac.be [Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Verheyen, Kris, E-mail: kris.verheyen@ugent.be [Laboratory of Forestry, Department of Forest and Water Management, Ghent University, Geraardsbergsesteenweg 267, B-9090 Gontrode, Melle (Belgium); Samson, Roeland, E-mail: roeland.samson@ua.ac.be [Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)

    2011-10-15

    We aimed at evaluating the effect of low-level air pollution on leaf area fluctuating asymmetry (FAA) and specific leaf area (SLA) of Salix alba L., taking into account other environmental factors. Cuttings were grown in standardized conditions in the near vicinity of air quality measuring stations in Belgium. Variability of SLA and FAA between measuring stations explained 83% and 7.26%, respectively, of the total variability. FAA was not influenced by air pollution or environmental factors such as shading, herbivory, air temperature and humidity. SLA was increased by an increase in shadow, while NO{sub x} and O{sub 3} concentrations had only a marginal influence. The influence of SO{sub 2} concentration was negligible. Although our data analysis suggests a relationship between SLA and NO{sub x}/O{sub 3} concentration, the absence of a straightforward relationship between FAA and SLA and air pollution still questions the usefulness of these bio-indicators for monitoring air pollution. - Highlights: > Leaf characteristics of white willow as possible bio-indicators for air quality. > Fluctuating asymmetry is not a good bio-indicator for monitoring the air quality. > Shadow increases specific leaf area. > NO{sub x} and O{sub 3} change specific leaf area of white willow. - Specific leaf area of S. alba increased with increasing shade and, in less extent, with increasing NO{sub x} and decreasing O{sub 3} concentration, while leaf asymmetry did not respond to air pollution

  2. The effect of air pollution and other environmental stressors on leaf fluctuating asymmetry and specific leaf area of Salix alba L

    International Nuclear Information System (INIS)

    Wuytack, Tatiana; Wuyts, Karen; Van Dongen, Stefan; Baeten, Lander; Kardel, Fatemeh; Verheyen, Kris; Samson, Roeland

    2011-01-01

    We aimed at evaluating the effect of low-level air pollution on leaf area fluctuating asymmetry (FAA) and specific leaf area (SLA) of Salix alba L., taking into account other environmental factors. Cuttings were grown in standardized conditions in the near vicinity of air quality measuring stations in Belgium. Variability of SLA and FAA between measuring stations explained 83% and 7.26%, respectively, of the total variability. FAA was not influenced by air pollution or environmental factors such as shading, herbivory, air temperature and humidity. SLA was increased by an increase in shadow, while NO x and O 3 concentrations had only a marginal influence. The influence of SO 2 concentration was negligible. Although our data analysis suggests a relationship between SLA and NO x /O 3 concentration, the absence of a straightforward relationship between FAA and SLA and air pollution still questions the usefulness of these bio-indicators for monitoring air pollution. - Highlights: → Leaf characteristics of white willow as possible bio-indicators for air quality. → Fluctuating asymmetry is not a good bio-indicator for monitoring the air quality. → Shadow increases specific leaf area. → NO x and O 3 change specific leaf area of white willow. - Specific leaf area of S. alba increased with increasing shade and, in less extent, with increasing NO x and decreasing O 3 concentration, while leaf asymmetry did not respond to air pollution

  3. Leucocyte profile and offspring production of guinea pig (Cavia cobaya given Anredera cordifolia leaf extract

    Directory of Open Access Journals (Sweden)

    D. Wijayanti

    2018-03-01

    Full Text Available The objective of this study was to determine leucocyte and offspring production of guinea pig (Cavia cobaya giving Anredera cordifolia leaf extract. Materials used were female 16 heads of guinea pig with body weight of 425g. The treatments were an extract of A. cordifolia leaf at doses of 0, 10, 50 and 90 mg/head, designated as T0, T1, T2 and T3, respectively. A. cordifolia leaf extract was administered orally from 10 days prepartum to 10 days postpartum. Blood was taken at 10 days prepartum and 10 days postpartum. Total birth of the offspring was observed. Data were analyzed by analysis of variance and if there was effect of treatment, then continued with Duncan multiple range test and Chi-Square test for fetal production between the given A. cordifolia leaf extract and control. The result showed that there was no significant difference for 10 days prepartum after addition of A cordifolia leaf extract treatment. The postpartum treated showed a total 50 mg/head level increaed for monocytes than that of level 0, 10 and 90 mg/head. Ten days postpartum treatment showed the total increase for leucocyte and monocytes total were 50 and 90 mg/head, respectively compared to 10 mg/head level. Total lymphocyte of 90 mg/head increased compared to level 10 and 50 mg/head. The highest total neutrophil as found at level of 50 mg/head which increased compared to the level of 0 and 10 mg/head. ProvisioningA. cordifolialeaf extract at doses level of 50 and 90 mg/head could increase litter size (P<0.05; χ2=9.267 and decreased offspring mortality (P<0.05; χ2=6.4. In conclusion, by giving 50 mg/head A. cordifolia leaf extract could increase leucocyte profile and offspring production of guinea pig.

  4. Leaf Physiological and Morphological Responses to Shade in Grass-Stage Seedlings and Young Trees of Longleaf Pine

    Directory of Open Access Journals (Sweden)

    Lisa J. Samuelson

    2012-08-01

    Full Text Available Longleaf pine has been classified as very shade intolerant but leaf physiological plasticity to light is not well understood, especially given longleaf pine’s persistent seedling grass stage. We examined leaf morphological and physiological responses to light in one-year-old grass-stage seedlings and young trees ranging in height from 4.6 m to 6.3 m to test the hypothesis that young longleaf pine would demonstrate leaf phenotypic plasticity to light environment. Seedlings were grown in a greenhouse under ambient levels of photosynthetically active radiation (PAR or a 50% reduction in ambient PAR and whole branches of trees were shaded to provide a 50% reduction in ambient PAR. In seedlings, shading reduced leaf mass per unit area (LMA, the light compensation point, and leaf dark respiration (RD, and increased the ratio of light-saturated photosynthesis to RD and chlorophyll b and total chlorophyll expressed per unit leaf dry weight. In trees, shading reduced LMA, increased chlorophyll a, chlorophyll b and total chlorophyll on a leaf dry weight basis, and increased allocation of total foliar nitrogen to chlorophyll nitrogen. Changes in leaf morphological and physiological traits indicate a degree of shade tolerance that may have implications for even and uneven-aged management of longleaf pine.

  5. Timing and duration of autumn leaf development in Sweden

    Science.gov (United States)

    Bolmgren, Kjell

    2014-05-01

    The growing season is changing in both ends and autumn phases seem to be responding in more diverse ways than spring events. Indeed, we know little about autumn leaf phenological strategies and how they are correlated with fitness components or ecosystem properties, and how they vary between species and over bioclimatic gradients. In this study more than 10 000 students were involved in observing autumn leaf development at 378 sites all over Sweden (55-68°N). They followed an image based observation protocol classifying autumn leaf development into five levels, from summer green (level 0) to 100% autumn leaf colored (level 4) canopy. In total, they submitted almost 12 000 observations between August 9 and November 15. 75% of the observations were made on the common species of Populus tremula, Betula pendula/pubescens and Sorbus aucuparia. The expected (negative) correlation between latitude and start of leaf senescence (level 2) was found in Populus and Betula, but not in Sorbus. The duration of the leaf senescence period, defined as the period between 1/3 (level 2) and 100% (level 4) of the canopy autumn leaf colored, was negatively correlated with latitude in Populus and Betula, but not in Sorbus. There was also a strong (negative) correlation of the start (level 2) and the duration of the leaf senescence in the early senescing Sorbus and Betula, while this effect was weaker in the late senescing Populus.

  6. Leaf area index from litter collection: impact of specific leaf area variability within a beech stand

    Energy Technology Data Exchange (ETDEWEB)

    Bouriaud, O. [Inst. National de la Recherche Agronomique, Centre de Recherches Forestieres de Nancy, Champenoux (France); Soudani, K. [Univ. Paris-Sud XI, Dept. d' Ecophysiologie Vegetale, Lab. Ecologie Systematique et Evolution, Orsay Cedex (France); Breda, N. [Inst. National de la Recherche Agronomique, Centre de Recherches Forestieres de Nancy, Champenoux (France)

    2003-06-01

    Litter fall collection is a direct method widely used to estimate leaf area index (LAI) in broad-leaved forest stands. Indirect measurements using radiation transmittance and gap fraction theory are often compared and calibrated against litter fall, which is considered as a reference method, but few studies address the question of litter specific leaf area (SLA) measurement and variability. SLA (leaf area per unit of dry weight, m{sup 2}{center_dot}g{sup -1}) is used to convert dry leaf litter biomass (g .m{sup -}2) into leaf area per ground unit area (m{sup 2}{center_dot}m{sup -2}). We paid special attention to this parameter in two young beech stands (dense and thinned) in northeastern France. The variability of both canopy (closure, LAI) and site conditions (soil properties, vegetation) was investigated as potential contributing factors to beech SLA variability. A systematic description of soil and floristic composition was performed and three types of soil were identified. Ellenberg's indicator values were averaged for each plot to assess nitrogen soil content. SLA of beech litter was measured three times during the fall in 23 plots in the stands (40 ha). Litter was collected bimonthly in square-shaped traps (0.5 m{sup 2}) and dried. Before drying, 30 leaves per plot and for each date were sampled, and leaf length, width, and area were measured with the help of a LI-COR areameter. SLA was calculated as the ratio of cumulated leaf area to total dry weight of the 30 leaves. Leaves characteristics per plot were averaged for the three dates of litter collection. Plant area index (PAI), estimated using the LAI-2000 plant canopy analyser and considering only the upper three rings, ranged from 2.9 to 8.1. Specific leaf area of beech litter was also highly different from one plot to the other, ranging from 150 to 320 cm{sup 2}{center_dot}g{sup -1}. Nevertheless, no relationship was found between SLA and stand canopy closure or PAI On the contrary, a significant

  7. Leaf area index from litter collection: impact of specific leaf area variability within a beech stand

    International Nuclear Information System (INIS)

    Bouriaud, O.; Soudani, K.; Breda, N.

    2003-01-01

    Litter fall collection is a direct method widely used to estimate leaf area index (LAI) in broad-leaved forest stands. Indirect measurements using radiation transmittance and gap fraction theory are often compared and calibrated against litter fall, which is considered as a reference method, but few studies address the question of litter specific leaf area (SLA) measurement and variability. SLA (leaf area per unit of dry weight, m 2 ·g -1 ) is used to convert dry leaf litter biomass (g .m - 2) into leaf area per ground unit area (m 2 ·m -2 ). We paid special attention to this parameter in two young beech stands (dense and thinned) in northeastern France. The variability of both canopy (closure, LAI) and site conditions (soil properties, vegetation) was investigated as potential contributing factors to beech SLA variability. A systematic description of soil and floristic composition was performed and three types of soil were identified. Ellenberg's indicator values were averaged for each plot to assess nitrogen soil content. SLA of beech litter was measured three times during the fall in 23 plots in the stands (40 ha). Litter was collected bimonthly in square-shaped traps (0.5 m 2 ) and dried. Before drying, 30 leaves per plot and for each date were sampled, and leaf length, width, and area were measured with the help of a LI-COR areameter. SLA was calculated as the ratio of cumulated leaf area to total dry weight of the 30 leaves. Leaves characteristics per plot were averaged for the three dates of litter collection. Plant area index (PAI), estimated using the LAI-2000 plant canopy analyser and considering only the upper three rings, ranged from 2.9 to 8.1. Specific leaf area of beech litter was also highly different from one plot to the other, ranging from 150 to 320 cm 2 ·g -1 . Nevertheless, no relationship was found between SLA and stand canopy closure or PAI On the contrary, a significant relationship between SLA and soil properties was observed. Both SLA

  8. From leaf longevity to canopy seasonality: a carbon optimality phenology model for tropical evergreen forests

    Science.gov (United States)

    Xu, X.; Medvigy, D.; Wu, J.; Wright, S. J.; Kitajima, K.; Pacala, S. W.

    2016-12-01

    Tropical evergreen forests play a key role in the global carbon, water and energy cycles. Despite apparent evergreenness, this biome shows strong seasonality in leaf litter and photosynthesis. Recent studies have suggested that this seasonality is not directly related to environmental variability but is dominated by seasonal changes of leaf development and senescence. Meanwhile, current terrestrial biosphere models (TBMs) can not capture this pattern because leaf life cycle is highly underrepresented. One challenge to model this leaf life cycle is the remarkable diversity in leaf longevity, ranging from several weeks to multiple years. Ecologists have proposed models where leaf longevity is regarded as a strategy to optimize carbon gain. However previous optimality models can not be readily integrated into TBMs because (i) there are still large biases in predicted leaf longevity and (ii) it is never tested whether the carbon optimality model can capture the observed seasonality in leaf demography and canopy photosynthesis. In this study, we develop a new carbon optimality model for leaf demography. The novelty of our approach is two-fold. First, we incorporate a mechanistic photosynthesis model that can better estimate leaf carbon gain. Second, we consider the interspecific variations in leaf senescence rate, which strongly influence the modelled optimal carbon gain. We test our model with a leaf trait database for Panamanian evergreen forests. Then, we apply the model at seasonal scale and compare simulated seasonality of leaf litter and canopy photosynthesis with in-situ observations from several Amazonian forest sites. We find that (i) compared with original optimality model, the regression slope between observed and predicted leaf longevity increases from 0.15 to 1.04 in our new model and (ii) that our new model can capture the observed seasonal variations of leaf demography and canopy photosynthesis. Our results suggest that the phenology in tropical evergreen

  9. Phenotypic plasticity and local adaptation in leaf ecophysiological traits of 13 contrasting cork oak populations under different water availabilities.

    Science.gov (United States)

    Ramírez-Valiente, Jose Alberto; Sánchez-Gómez, David; Aranda, Ismael; Valladares, Fernando

    2010-05-01

    Plants distributed across a wide range of environmental conditions are submitted to differential selective pressures. Long-term selection can lead to the development of adaptations to the local environment, generating ecotypic differentiation. Additionally, plant species can cope with this environmental variability by phenotypic plasticity. In this study, we examine the importance of both processes in coping with environmental heterogeneity in the Mediterranean sclerophyllous cork oak Quercus suber. For this purpose, we measured growth and key functional traits at the leaf level in 9-year-old plants across 2 years of contrasting precipitation (2005 and 2006) in a common garden. Plants were grown from acorns originated from 13 populations spanning a wide range of climates along the distribution range of the species. The traits measured were: leaf size (LS), specific leaf area (SLA), carbon isotope discrimination (Delta(13)C) and leaf nitrogen content per unit mass (N(mass)). Inter-population differences in LS, SLA and Delta(13)C were found. These differences were associated with rainfall and temperature at the sites of origin, suggesting local adaptation in response to diverging climates. Additionally, SLA and LS exhibited positive responses to the increase in annual rainfall. Year effect explained 28% of the total phenotypic variance in LS and 2.7% in SLA. There was a significant genotype x environment interaction for shoot growth and a phenotypic correlation between the difference in shoot growth among years and the annual mean temperature at origin. This suggests that populations originating from warm sites can benefit more from wet conditions than populations from cool sites. Finally, we investigated the relationships between functional traits and aboveground growth by several regression models. Our results showed that plants with lower SLA presented larger aboveground growth in a dry year and plants with larger leaf sizes displayed larger growth rates in both

  10. Phytochemical Analysis, Antifungal and Antioxidant Activity of Leaf ...

    African Journals Online (AJOL)

    Science, Technology and Arts Research Journal ... of total phenolics, antifungal and antioxidant activity of leaf and fruit extract of Zizyphus xylopyrus (Retz.) ... Flavonoids, saponins, terpenoids, tannins and phenols were found in both extracts.

  11. Characterization and genetic mapping of eceriferum-ym (cer-ym), a cutin deficient barley mutant with impaired leaf water retention capacity.

    Science.gov (United States)

    Li, Chao; Liu, Cheng; Ma, Xiaoying; Wang, Aidong; Duan, Ruijun; Nawrath, Christiane; Komatsuda, Takao; Chen, Guoxiong

    2015-09-01

    The cuticle covers the aerial parts of land plants, where it serves many important functions, including water retention. Here, a recessive cuticle mutant, eceriferum-ym (cer-ym), of Hordeum vulgare L. (barley) showed abnormally glossy spikes, sheaths, and leaves. The cer-ym mutant plant detached from its root system was hypersensitive to desiccation treatment compared with wild type plants, and detached leaves of mutant lost 41.8% of their initial weight after 1 h of dehydration under laboratory conditions, while that of the wild type plants lost only 7.1%. Stomata function was not affected by the mutation, but the mutant leaves showed increased cuticular permeability to water, suggesting a defective leaf cuticle, which was confirmed by toluidine blue staining. The mutant leaves showed a substantial reduction in the amounts of the major cutin monomers and a slight increase in the main wax component, suggesting that the enhanced cuticle permeability was a consequence of cutin deficiency. cer-ym was mapped within a 0.8 cM interval between EST marker AK370363 and AK251484, a pericentromeric region on chromosome 4H. The results indicate that the desiccation sensitivity of cer-ym is caused by a defect in leaf cutin, and that cer-ym is located in a chromosome 4H pericentromeric region.

  12. Response of the water status of soybean to changes in soil water potentials controlled by the water pressure in microporous tubes

    Science.gov (United States)

    Steinberg, S. L.; Henninger, D. L.

    1997-01-01

    Water transport through a microporous tube-soil-plant system was investigated by measuring the response of soil and plant water status to step change reductions in the water pressure within the tubes. Soybeans were germinated and grown in a porous ceramic 'soil' at a porous tube water pressure of -0.5 kpa for 28 d. During this time, the soil matric potential was nearly in equilibrium with tube water pressure. Water pressure in the porous tubes was then reduced to either -1.0, -1.5 or -2.0 kPa. Sap flow rates, leaf conductance and soil, root and leaf water potentials were measured before and after this change. A reduction in porous tube water pressure from -0.5 to -1.0 or -1.5 kPa did not result in any significant change in soil or plant water status. A reduction in porous tube water pressure to -2.0 kPa resulted in significant reductions in sap flow, leaf conductance, and soil, root and leaf water potentials. Hydraulic conductance, calculated as the transpiration rate/delta psi between two points in the water transport pathway, was used to analyse water transport through the tube-soil-plant continuum. At porous tube water pressures of -0.5 to-1.5 kPa soil moisture was readily available and hydraulic conductance of the plant limited water transport. At -2.0 kPa, hydraulic conductance of the bulk soil was the dominant factor in water movement.

  13. Edge type affects leaf-level water relations and estimated transpiration of Eucalyptus arenacea.

    Science.gov (United States)

    Wright, Thomas E; Tausz, Michael; Kasel, Sabine; Volkova, Liubov; Merchant, Andrew; Bennett, Lauren T

    2012-03-01

    While edge effects on tree water relations are well described for closed forests, they remain under-examined in more open forest types. Similarly, there has been minimal evaluation of the effects of contrasting land uses on the water relations of open forest types in highly fragmented landscapes. We examined edge effects on the water relations and gas exchange of a dominant tree (Eucalyptus arenacea Marginson & Ladiges) in an open forest type (temperate woodland) of south-eastern Australia. Edge effects in replicate woodlands adjoined by cleared agricultural land (pasture edges) were compared with those adjoined by 7- to 9-year-old eucalypt plantation with a 25m fire break (plantation edges). Consistent with studies in closed forest types, edge effects were pronounced at pasture edges where photosynthesis, transpiration and stomatal conductance were greater for edge trees than interior trees (75m into woodlands), and were related to greater light availability and significantly higher branch water potentials at woodland edges than interiors. Nonetheless, gas exchange values were only ∼50% greater for edge than interior trees, compared with ∼200% previously found in closed forest types. In contrast to woodlands adjoined by pasture, gas exchange in winter was significantly lower for edge than interior trees in woodlands adjoined by plantations, consistent with shading and buffering effects of plantations on edge microclimate. Plantation edge effects were less pronounced in summer, although higher water use efficiency of edge than interior woodland trees indicated possible competition for water between plantation trees and woodland edge trees in the drier months (an effect that might have been more pronounced were there no firebreak between the two land uses). Scaling up of leaf-level water relations to stand transpiration using a Jarvis-type phenomenological model indicated similar differences between edge types. That is, transpiration was greater at pasture than

  14. Convergence of tree water use within an arid-zone woodland.

    Science.gov (United States)

    O'Grady, A P; Cook, P G; Eamus, D; Duguid, A; Wischusen, J D H; Fass, T; Worldege, D

    2009-07-01

    We examined spatial and temporal patterns of tree water use and aspects of hydraulic architecture in four common tree species of central Australia--Corymbia opaca, Eucalyptus victrix, E. camaldulensis and Acacia aneura--to better understand processes that constrain water use in these environments. These four widely distributed species occupy contrasting niches within arid environments including woodlands, floodplains and riparian environments. Measurements of tree water use and leaf water potential were made at two sites with contrasting water table depths during a period of high soil water availability following summer rainfall and during a period of low soil water availability following 7 months of very little rainfall during 2007. There were significant differences in specific leaf area (SLA), sapwood area to leaf area ratios and sapwood density between species. Sapwood to leaf area ratio increased in all species from April to November indicating a decline in leaf area per unit sapwood area. Despite very little rainfall in the intervening period three species, C. opaca, E. victrix and E. camaldulensis maintained high leaf water potentials and tree water use during both periods. In contrast, leaf water potential and water use in the A. aneura were significantly reduced in November compared to April. Despite contrasting morphology and water use strategies, we observed considerable convergence in water use among the four species. Wood density in particular was strongly related to SLA, sapwood area to leaf area ratios and soil to leaf conductance, with all four species converging on a common relationship. Identifying convergence in hydraulic traits can potentially provide powerful tools for scaling physiological processes in natural ecosystems.

  15. Comparative Study on the Antioxidant Activity of Leaf Extract and Carotenoids Extract from Ipomoea batatas var. Oren (Sweetpotato) Leaves

    OpenAIRE

    Seow-Mun Hue; Amru Nasrulhaq Boyce; Chandran Somasundram

    2011-01-01

    Ipomoea batatas (Sweetpotato) is currently ranked sixth in the total world food production and are planted mainly for their storage roots. The present study was undertaken to evaluate and compare the antioxidant properties of the leaf and carotenoids extract from the Ipomoea batatas var. Oren leaves. Total flavonoids in the leaf extract was 144.6 ± 40.5 μg/g compared to 114.86 ± 4.35 μg/g catechin equivalent in the carotenoids extract. Total polyphenols in the leaf extrac...

  16. Measured and modelled leaf and stand-scale productivity across a soil moisture gradient and a severe drought.

    Science.gov (United States)

    Wright, J K; Williams, M; Starr, G; McGee, J; Mitchell, R J

    2013-02-01

    Environmental controls on carbon dynamics operate at a range of interacting scales from the leaf to landscape. The key questions of this study addressed the influence of water and nitrogen (N) availability on Pinus palustris (Mill.) physiology and primary productivity across leaf and canopy scales, linking the soil-plant-atmosphere (SPA) model to leaf and stand-scale flux and leaf trait/canopy data. We present previously unreported ecophysiological parameters (e.g. V(cmax) and J(max)) for P. palustris and the first modelled estimates of its annual gross primary productivity (GPP) across xeric and mesic sites and under extreme drought. Annual mesic site P. palustris GPP was ∼23% greater than at the xeric site. However, at the leaf level, xeric trees had higher net photosynthetic rates, and water and light use efficiency. At the canopy scale, GPP was limited by light interception (canopy level), but co-limited by nitrogen and water at the leaf level. Contrary to expectations, the impacts of an intense growing season drought were greater at the mesic site. Modelling indicated a 10% greater decrease in mesic GPP compared with the xeric site. Xeric P. palustris trees exhibited drought-tolerant behaviour that contrasted with mesic trees' drought-avoidance behaviour. © 2012 Blackwell Publishing Ltd.

  17. Why do leaf-tying caterpillars abandon their leaf ties?

    Directory of Open Access Journals (Sweden)

    Michelle Sliwinski

    2013-09-01

    Full Text Available Leaf-tying caterpillars act as ecosystem engineers by building shelters between overlapping leaves, which are inhabited by other arthropods. Leaf-tiers have been observed to leave their ties and create new shelters (and thus additional microhabitats, but the ecological factors affecting shelter fidelity are poorly known. For this study, we explored the effects of resource limitation and occupant density on shelter fidelity and assessed the consequences of shelter abandonment. We first quantified the area of leaf material required for a caterpillar to fully develop for two of the most common leaf-tiers that feed on white oak, Quercus alba. On average, Psilocorsis spp. caterpillars consumed 21.65 ± 0.67 cm2 leaf material to complete development. We also measured the area of natural leaf ties found in a Maryland forest, to determine the distribution of resources available to caterpillars in situ. Of 158 natural leaf ties examined, 47% were too small to sustain an average Psilocorsis spp. caterpillar for the entirety of its development. We also manipulated caterpillar densities within experimental ties on potted trees to determine the effects of cohabitants on the likelihood of a caterpillar to leave its tie. We placed 1, 2, or 4 caterpillars in ties of a standard size and monitored the caterpillars twice daily to track their movement. In ties with more than one occupant, caterpillars showed a significantly greater propensity to leave their tie, and left sooner and at a faster rate than those in ties as single occupants. To understand the consequences of leaf tie abandonment, we observed caterpillars searching a tree for a site to build a shelter in the field. This is a risky behavior, as 17% of the caterpillars observed died while searching for a shelter site. Caterpillars that successfully built a shelter traveled 110 ± 20 cm and took 28 ± 7 min to find a suitable site to build a shelter. In conclusion, leaf-tying caterpillars must frequently

  18. 78 FR 10269 - National Primary Drinking Water Regulations: Revisions to the Total Coliform Rule

    Science.gov (United States)

    2013-02-13

    ... Illness CWS--Community Water System DBP--Disinfection Byproduct DWC--Drinking Water Committee EA--Economic... 141 and 142 National Primary Drinking Water Regulations: Revisions to the Total Coliform Rule; Final...-9684-8] RIN 2040-AD94 National Primary Drinking Water Regulations: Revisions to the Total Coliform Rule...

  19. Leaf nutrient contents and morphology of invasive tamarisk in different soil conditions in the lower Virgin River

    Science.gov (United States)

    Imada, S.; Acharya, K.; Tateno, R.; Yamanaka, N.

    2012-12-01

    Invasive plants can alter ecosystem nitrogen (N) cycling. To increase our understanding of nutrient use strategy of invasive tamarisk (Tamarix spp.) on an arid riparian ecosystem, we examined leaf nutrient contents and morphology of Tamarix ramosissima and its relationship with soil properties in the lower Virgin River floodplain, Nevada, U.S. Leaves were collected in three different locations; near the river, near the stand edge (60-70 m from the river edge) and at 30-40 m from the river edge in the summer of 2011. Leaves were analyzed for carbon (C) and N contents, and specific leaf area (SLA). Soil samples at 10-20 cm depths and under the canopy were also collected for soil water, pH, electrical conductivity (EC) and inorganic nitrogen (NO3- and NH4+) analysis. Results suggested that tree size and SLA increased with decreasing distance from the river, whereas C isotope discrimination did not differ among the samples based on distance from the river. Nitrogen content per unit mass and N isotope discrimination (δ15N) were significantly higher in the trees near the river. Soil NO3- and total inorganic N had positive relationships with δ15N in leaves, which suggests that leaf δ15N may be influenced by N concentrations on the soil surface. Negative correlations were found between soil EC and leaf N contents, suggesting that high soil salinity may decrease Tamarix leaf N and thus limit tree growth.

  20. Growth form and seasonal variation in leaf gas exchange of Colophospermum mopane savanna trees in northwest Botswana.

    Science.gov (United States)

    Veenendaal, Elmar M; Mantlana, Khanyisa B; Pammenter, Norman W; Weber, Piet; Huntsman-Mapila, Phillipa; Lloyd, Jon

    2008-03-01

    We investigated differences in physiological and morphological traits between the tall and short forms of mopane (Colophospermum mopane (Kirk ex Benth.) Kirk ex J. Léonard) trees growing near Maun, Botswana on a Kalahari sandveld overlying an impermeable calcrete duricrust. We sought to determine if differences between the two physiognomic types are attributable to the way they exploit available soil water. The tall form, which was located on deeper soil than the short form (5.5 versus 1.6 m), had a lower leaf:fine root biomass ratio (1:20 versus 1:6), but a similar leaf area index (0.9-1.0). Leaf nitrogen concentrations varied between 18 and 27 mg g(-1) and were about 20% higher in the tall form than in the short form. Maximum net assimilation rates (A sat) occurred during the rainy seasons (March-April 2000 and January-February 2001) and were similar in the tall and short forms (15-22 micromol m(-2) s(-1)) before declining to less than 10 micromol m(-2) s(-1) at the end of the rainy season in late April. As the dry season progressed, A sat, soil water content, predawn leaf water potential (Psi pd) and leaf nitrogen concentration declined rapidly. Before leaf abscission, Psi pd was more negative in the short form (-3.4 MPa) than in the tall form (-2.7 MPa) despite the greater availability of soil water beneath the short form trees. This difference appeared attributable to differences in root depth and density between the physiognomic types. Stomatal regulation of water use and carbon assimilation differed between years, with the tall form having a consistently more conservative water-use strategy as the dry season progressed than the short form.

  1. Gas exchange recovery following natural drought is rapid unless limited by loss of leaf hydraulic conductance: evidence from an evergreen woodland.

    Science.gov (United States)

    Skelton, Robert P; Brodribb, Timothy J; McAdam, Scott A M; Mitchell, Patrick J

    2017-09-01

    Drought can cause major damage to plant communities, but species damage thresholds and postdrought recovery of forest productivity are not yet predictable. We used an El Niño drought event as a natural experiment to test whether postdrought recovery of gas exchange could be predicted by properties of the water transport system, or if metabolism, primarily high abscisic acid concentration, might delay recovery. We monitored detailed physiological responses, including shoot sapflow, leaf gas exchange, leaf water potential and foliar abscisic acid (ABA), during drought and through the subsequent rehydration period for a sample of eight canopy and understory species. Severe drought caused major declines in leaf water potential, elevated foliar ABA concentrations and reduced stomatal conductance and assimilation rates in our eight sample species. Leaf water potential surpassed levels associated with incipient loss of leaf hydraulic conductance in four species. Following heavy rainfall gas exchange in all species, except those trees predicted to have suffered hydraulic impairment, recovered to prestressed rates within 1 d. Recovery of plant gas exchange was rapid and could be predicted by the hydraulic safety margin, providing strong support for leaf vulnerability to water deficit as an index of damage under natural drought conditions. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  2. Physiological basis of genetic variation in leaf photosynthesis among rice (Oryza sativa L.) introgression lines under drought and well-watered conditions

    Science.gov (United States)

    Yin, Xinyou

    2012-01-01

    To understand the physiological basis of genetic variation and resulting quantitative trait loci (QTLs) for photosynthesis in a rice (Oryza sativa L.) introgression line population, 13 lines were studied under drought and well-watered conditions, at flowering and grain filling. Simultaneous gas exchange and chlorophyll fluorescence measurements were conducted at various levels of incident irradiance and ambient CO2 to estimate parameters of a model that dissects photosynthesis into stomatal conductance (g s), mesophyll conductance (g m), electron transport capacity (J max), and Rubisco carboxylation capacity (V cmax). Significant genetic variation in these parameters was found, although drought and leaf age accounted for larger proportions of the total variation. Genetic variation in light-saturated photosynthesis and transpiration efficiency (TE) were mainly associated with variation in g s and g m. One previously mapped major QTL of photosynthesis was associated with variation in g s and g m, but also in J max and V cmax at flowering. Thus, g s and g m, which were demonstrated in the literature to be responsible for environmental variation in photosynthesis, were found also to be associated with genetic variation in photosynthesis. Furthermore, relationships between these parameters and leaf nitrogen or dry matter per unit area, which were previously found across environmental treatments, were shown to be valid for variation across genotypes. Finally, the extent to which photosynthesis rate and TE can be improved was evaluated. Virtual ideotypes were estimated to have 17.0% higher photosynthesis and 25.1% higher TE compared with the best genotype investigated. This analysis using introgression lines highlights possibilities of improving both photosynthesis and TE within the same genetic background. PMID:22888131

  3. Bacteriological (fecal and total coliform) quality of Pakistani coastal water

    International Nuclear Information System (INIS)

    Mashiatullah, A.; Qureshi, R.M.; Javed, T.; Khan, M.S.; Chaudhary, M.Z.; Khalid, F.

    2010-01-01

    The coliform bacteria group consists of several genera of bacteria belonging to the family enterobacteriaceae. These are harmless bacteria, mostly live in soil, water, and digestive system of animals. Fecal coliform bacteria, which belongs to this group, are present in large numbers in feces and intestinal tract of human beings and other warm-blooded animals which can enter into water bodies from human and animal waste. Swimming in water having high levels of Fecal coliform bacteria increases the chance of developing illness (fever, nausea or stomach cramps) from pathogens entering the body through mouth, nose, ears or cuts in the skin. The objective of the present study was to characterize the bathing quality of Pakistani coastal water with respect to coliform bacteria. Total and Fecal coliform bacteria were determined at seven different locations along Pakistan coast using membrane filtration (MF) technique. 100 ml of water was passed through 0.45 micron (mu) filter paper. These filter papers were put on pads, soaked in Lauryle sulphate broth in petri-dishes and incubated at 44 deg. C for Fecal and 37 deg. for Total coliform for 24 hours. Significantly high population of Fecal and Total coliform bacteria was recorded at Karachi harbour area and Indus delta region. Results indicate that a large amount of domestically originated waste is being discharged into these locations without any pre-treatment (e.g., screening, activated sludge, by using filtration beds etc.) resulting in a poor seawater quality making it unfit for bathing. (author)

  4. Height-related changes in leaf photosynthetic traits in diverse Bornean tropical rain forest trees.

    Science.gov (United States)

    Kenzo, Tanaka; Inoue, Yuta; Yoshimura, Mitsunori; Yamashita, Megumi; Tanaka-Oda, Ayumi; Ichie, Tomoaki

    2015-01-01

    Knowledge of variations in morphophysiological leaf traits with forest height is essential for quantifying carbon and water fluxes from forest ecosystems. Here, we examined changes in leaf traits with forest height in diverse tree species and their role in environmental acclimation in a tropical rain forest in Borneo that does not experience dry spells. Height-related changes in leaf physiological and morphological traits [e.g., maximum photosynthetic rate (Amax), stomatal conductance (gs), dark respiration rate (Rd), carbon isotope ratio (δ(13)C), nitrogen (N) content, and leaf mass per area (LMA)] from understory to emergent trees were investigated in 104 species in 29 families. We found that many leaf area-based physiological traits (e.g., A(max-area), Rd, gs), N, δ(13)C, and LMA increased linearly with tree height, while leaf mass-based physiological traits (e.g., A(max-mass)) only increased slightly. These patterns differed from other biomes such as temperate and tropical dry forests, where trees usually show decreased photosynthetic capacity (e.g., A(max-area), A(max-mass)) with height. Increases in photosynthetic capacity, LMA, and δ(13)C are favored under bright and dry upper canopy conditions with higher photosynthetic productivity and drought tolerance, whereas lower R d and LMA may improve shade tolerance in lower canopy trees. Rapid recovery of leaf midday water potential to theoretical gravity potential during the night supports the idea that the majority of trees do not suffer from strong drought stress. Overall, leaf area-based photosynthetic traits were associated with tree height and the degree of leaf drought stress, even in diverse tropical rain forest trees.

  5. Lipid peroxidation inhibition and antiradical activities of some leaf fractions of Mangifera indica.

    Science.gov (United States)

    Badmus, Jelili A; Adedosu, Temitope O; Fatoki, John O; Adegbite, Victor A; Adaramoye, Oluwatosin A; Odunola, Oyeronke A

    2011-01-01

    This study was undertaken to assess in vitro lipid peroxidation inhibitions and anti-radical activities of methanolic, chloroform, ethyl acetate and water fractions of Mangifera indica leaf. Inhibition of Fe(2+)-induced lipid peroxidation (LPO) in egg, brain, and liver homogenates, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl (OH-) radical scavenging activities were evaluated. Total phenol was assessed in all fractions, and the reducing power of methanolic fraction was compared to gallic acid and ascorbic acid. The results showed that Fe2+ induced significant lipid peroxidation (LPO) in all the homogenates. Ethyl acetate fraction showed the highest percentage inhibition of LPO in both egg yolk (68.3%) and brain (66.3%), while the aqueous fraction exerted the highest inhibition in liver homogenate (89.1%) at a concentration of 10 microg/mL. These observed inhibitions of LPO by these fractions were higher than that of ascorbic acid used as a standard. The DPPH radical scavenging ability exhibited by ethyl acetate fraction was found to be the highest with IC50 value of 1.5 microg/mL. The ethyl acetate and methanolic fractions had the highest OH- radical scavenging ability with the same IC50 value of 5 microg/mL. The total phenol content of ethyl acetate fraction was the highest with 0.127 microg/mg gallic acid equivalent (GAE). The reductive potential of methanolic fraction showed a concentration-dependent increase. This study showed that inhibition of LPO and the DPPH and OH- radicals scavenging abilities of Mangifera indica leaf could be related to the presence of phenolic compounds. Therefore, the ethyl acetate fraction of the leaf may be a good source of natural antioxidative agent.

  6. Does oolong tea (Camellia sinensis) made from a combination of leaf and stem smell more aromatic than leaf-only tea? Contribution of the stem to oolong tea aroma.

    Science.gov (United States)

    Zeng, Lanting; Zhou, Ying; Fu, Xiumin; Mei, Xin; Cheng, Sihua; Gui, Jiadong; Dong, Fang; Tang, Jinchi; Ma, Shengzhou; Yang, Ziyin

    2017-12-15

    The raw materials used to make oolong tea (Camellia sinensis) are a combination of leaf and stem. Oolong tea made from leaf and stem is thought to have a more aromatic smell than leaf-only tea. However, there is no available evidence to support the viewpoint. In this study, sensory evaluation and detailed characterization of emitted and internal volatiles (not readily emitted, but stored in samples) of dry oolong teas and infusions indicated that the presence of stem did not significantly improve the total aroma characteristics. During the enzyme-active processes, volatile monoterpenes and theanine were accumulated more abundantly in stem than in leaf, while jasmine lactone, indole, and trans-nerolidol were lower in stem than in leaf. Tissue-specific aroma-related gene expression and availability of precursors of aroma compounds resulted in different aroma distributions in leaf and stem. This study presents the first determination of the contribution of stem to oolong tea aroma. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Effect of litter, leaf cover and cover of basal internodes of the dominant species Molinia caerulea on seedling recruitment and established vegetation

    Science.gov (United States)

    Janeček, Štěpán; Lepš, Jan

    2005-09-01

    The effects of litter removal, leaf cover of established plants and cover of basal internodes of a dominant species Molinia caerulea on seedling germination and the dynamics of established plants were studied in a field experiment in an oligotrophic wet meadow. Although the negative influence of litter on total seedling number and seedling species composition was non-significant, litter significantly affected the dynamics of the established vegetation and caused inhibition of total leaf cover development. The effects of total leaf cover of established plants on seedling establishment changed during the vegetation season. Whereas the effect of total leaf cover was positive at the start and in the middle of the vegetation season, at the end the total leaf cover negatively affected seedling establishment. Both total leaf cover and cover of basal internodes affected seedling composition. Effects of these two variables were statistically separable suggesting that they are based on different mechanisms. The response of seedling establishment to these factors was species specific and, consequently, our data support the hypothesis that that biotically generated spatial heterogeneity can promote species co-existence through the differentiation of species regeneration niches.

  8. Elimination of 137Cs from trefoil (leaf and stem), ''Mitsuba'', cryptotaenia japonica hassk, boiled in a distilled and salted waters

    International Nuclear Information System (INIS)

    Motegi, Misako; Miyake, Sadaaki; Ohsawa, Takashi; Nakazawa, Kiyoaki; Izumo, Yoshiro

    1999-01-01

    Elimination of 137 Cs from highly accumulated trefoil (leaf and stem) through boiling in distilled and salted water were investigated in relation to study the effect of cooking and processing on biochemical states of radionuclides (RI) contaminating in foods. 137 Cs was hardly eliminated from the trefoil immersed in a distilled water at room temperature (about 15degC) during 10 min. 137 Cs was considerably eliminated from the trefoil when boiled in a distilled water, 0.3-3.0% salt concentration of the water and soy sauce: about 40-60% (after 2 min), 70-85% (5 min) and 80-90% (10 min), respectively. Elimination of 137 Cs in the soy sauce (e.g. 77.0±2.9%, at 1% salt concentration after 10 min) was restrictive comparing to that in the salt water (93.4±2.3%). These results are expected to contribute to evaluate the radiation exposure to man when a boiled trefoil contaminating with 137 Cs was ingested. (author)

  9. Immobilization and mineralization of N and P by heterotrophic microbes during leaf decomposition

    Science.gov (United States)

    Beth Cheever; Erika Kratzer; Jackson Webster

    2012-01-01

    According to theory, the rate and stoichiometry of microbial mineralization depend, in part, on nutrient availability. For microbes associated with leaves in streams, nutrients are available from both the water column and the leaf. Therefore, microbial nutrient cycling may change with nutrient availability and during leaf decomposition. We explored spatial and temporal...

  10. Coordination of Leaf Photosynthesis, Transpiration, and Structural Traits in Rice and Wild Relatives (Genus Oryza).

    Science.gov (United States)

    Giuliani, Rita; Koteyeva, Nuria; Voznesenskaya, Elena; Evans, Marc A; Cousins, Asaph B; Edwards, Gerald E

    2013-07-01

    The genus Oryza, which includes rice (Oryza sativa and Oryza glaberrima) and wild relatives, is a useful genus to study leaf properties in order to identify structural features that control CO(2) access to chloroplasts, photosynthesis, water use efficiency, and drought tolerance. Traits, 26 structural and 17 functional, associated with photosynthesis and transpiration were quantified on 24 accessions (representatives of 17 species and eight genomes). Hypotheses of associations within, and between, structure, photosynthesis, and transpiration were tested. Two main clusters of positively interrelated leaf traits were identified: in the first cluster were structural features, leaf thickness (Thick(leaf)), mesophyll (M) cell surface area exposed to intercellular air space per unit of leaf surface area (S(mes)), and M cell size; a second group included functional traits, net photosynthetic rate, transpiration rate, M conductance to CO(2) diffusion (g(m)), stomatal conductance to gas diffusion (g(s)), and the g(m)/g(s) ratio.While net photosynthetic rate was positively correlated with gm, neither was significantly linked with any individual structural traits. The results suggest that changes in gm depend on covariations of multiple leaf (S(mes)) and M cell (including cell wall thickness) structural traits. There was an inverse relationship between Thick(leaf) and transpiration rate and a significant positive association between Thick(leaf) and leaf transpiration efficiency. Interestingly, high g(m) together with high g(m)/g(s) and a low S(mes)/g(m) ratio (M resistance to CO(2) diffusion per unit of cell surface area exposed to intercellular air space) appear to be ideal for supporting leaf photosynthesis while preserving water; in addition, thick M cell walls may be beneficial for plant drought tolerance.

  11. Detecting leaf pulvinar movements on NDVI time series of desert trees: a new approach for water stress detection.

    Directory of Open Access Journals (Sweden)

    Roberto O Chávez

    Full Text Available Heliotropic leaf movement or leaf 'solar tracking' occurs for a wide variety of plants, including many desert species and some crops. This has an important effect on the canopy spectral reflectance as measured from satellites. For this reason, monitoring systems based on spectral vegetation indices, such as the normalized difference vegetation index (NDVI, should account for heliotropic movements when evaluating the health condition of such species. In the hyper-arid Atacama Desert, Northern Chile, we studied seasonal and diurnal variations of MODIS and Landsat NDVI time series of plantation stands of the endemic species Prosopis tamarugo Phil., subject to different levels of groundwater depletion. As solar irradiation increased during the day and also during the summer, the paraheliotropic leaves of Tamarugo moved to an erectophile position (parallel to the sun rays making the NDVI signal to drop. This way, Tamarugo stands with no water stress showed a positive NDVI difference between morning and midday (ΔNDVI mo-mi and between winter and summer (ΔNDVI W-S. In this paper, we showed that the ΔNDVI mo-mi of Tamarugo stands can be detected using MODIS Terra and Aqua images, and the ΔNDVI W-S using Landsat or MODIS Terra images. Because pulvinar movement is triggered by changes in cell turgor, the effects of water stress caused by groundwater depletion can be assessed and monitored using ΔNDVI mo-mi and ΔNDVI W-S. For an 11-year time series without rainfall events, Landsat ΔNDVI W-S of Tamarugo stands showed a positive linear relationship with cumulative groundwater depletion. We conclude that both ΔNDVI mo-mi and ΔNDVI W-S have potential to detect early water stress of paraheliotropic vegetation.

  12. Detecting leaf pulvinar movements on NDVI time series of desert trees: a new approach for water stress detection.

    Science.gov (United States)

    Chávez, Roberto O; Clevers, Jan G P W; Verbesselt, Jan; Naulin, Paulette I; Herold, Martin

    2014-01-01

    Heliotropic leaf movement or leaf 'solar tracking' occurs for a wide variety of plants, including many desert species and some crops. This has an important effect on the canopy spectral reflectance as measured from satellites. For this reason, monitoring systems based on spectral vegetation indices, such as the normalized difference vegetation index (NDVI), should account for heliotropic movements when evaluating the health condition of such species. In the hyper-arid Atacama Desert, Northern Chile, we studied seasonal and diurnal variations of MODIS and Landsat NDVI time series of plantation stands of the endemic species Prosopis tamarugo Phil., subject to different levels of groundwater depletion. As solar irradiation increased during the day and also during the summer, the paraheliotropic leaves of Tamarugo moved to an erectophile position (parallel to the sun rays) making the NDVI signal to drop. This way, Tamarugo stands with no water stress showed a positive NDVI difference between morning and midday (ΔNDVI mo-mi) and between winter and summer (ΔNDVI W-S). In this paper, we showed that the ΔNDVI mo-mi of Tamarugo stands can be detected using MODIS Terra and Aqua images, and the ΔNDVI W-S using Landsat or MODIS Terra images. Because pulvinar movement is triggered by changes in cell turgor, the effects of water stress caused by groundwater depletion can be assessed and monitored using ΔNDVI mo-mi and ΔNDVI W-S. For an 11-year time series without rainfall events, Landsat ΔNDVI W-S of Tamarugo stands showed a positive linear relationship with cumulative groundwater depletion. We conclude that both ΔNDVI mo-mi and ΔNDVI W-S have potential to detect early water stress of paraheliotropic vegetation.

  13. A comparison of step-and-shoot leaf sequencing algorithms that eliminate tongue-and-groove effects

    Energy Technology Data Exchange (ETDEWEB)

    Kamath, Srijit [Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL (United States); Sahni, Sartaj [Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL (United States); Ranka, Sanjay [Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL (United States); Li, Jonathan [Department of Radiation Oncology, University of Florida, Gainesville, FL (United States); Palta, Jatinder [Department of Radiation Oncology, University of Florida, Gainesville, FL (United States)

    2004-07-21

    The performances of three recently published leaf sequencing algorithms for step-and-shoot intensity-modulated radiation therapy delivery that eliminates tongue-and-groove underdosage are evaluated. Proofs are given to show that the algorithm of Que et al (2004 Phys. Med. Biol. 49 399-405) generates leaf sequences free of tongue-and-groove underdosage and interdigitation. However, the total beam-on times could be up to n times those of the sequences generated by the algorithms of Kamath et al (2004 Phys. Med. Biol. 49 N7-N19), which are optimal in beam-on time for unidirectional leaf movement under the same constraints, where n is the total number of involved leaf pairs. Using 19 clinical fluence matrices and 100 000 randomly generated 15 x 15 matrices, the average monitor units and number of segments of the leaf sequences generated using the algorithm of Que et al are about two to four times those generated by the algorithm of Kamath et al.

  14. A comparison of step-and-shoot leaf sequencing algorithms that eliminate tongue-and-groove effects

    International Nuclear Information System (INIS)

    Kamath, Srijit; Sahni, Sartaj; Ranka, Sanjay; Li, Jonathan; Palta, Jatinder

    2004-01-01

    The performances of three recently published leaf sequencing algorithms for step-and-shoot intensity-modulated radiation therapy delivery that eliminates tongue-and-groove underdosage are evaluated. Proofs are given to show that the algorithm of Que et al (2004 Phys. Med. Biol. 49 399-405) generates leaf sequences free of tongue-and-groove underdosage and interdigitation. However, the total beam-on times could be up to n times those of the sequences generated by the algorithms of Kamath et al (2004 Phys. Med. Biol. 49 N7-N19), which are optimal in beam-on time for unidirectional leaf movement under the same constraints, where n is the total number of involved leaf pairs. Using 19 clinical fluence matrices and 100 000 randomly generated 15 x 15 matrices, the average monitor units and number of segments of the leaf sequences generated using the algorithm of Que et al are about two to four times those generated by the algorithm of Kamath et al

  15. Leaf Epidermis of the Rheophyte Dyckia brevifolia Baker (Bromeliaceae

    Directory of Open Access Journals (Sweden)

    Ghislaine Maria Lobo

    2013-01-01

    Full Text Available Some species of Dyckia Schult. f., including Dyckia brevifolia Baker, are rheophytes that live in the fast-moving water currents of streams and rivers which are subject to frequent flooding, but also period of low water. This study aimed to analyze the leaf epidermis of D. brevifolia in the context of epidermal adaptation to this aquatic plant’s rheophytic habitat. The epidermis is uniseriate, and the cuticle is thickened. The inner periclinal and anticlinal walls of the epidermal cells are thickened and lignified. Stomata are tetracytic, located in the depressions in relation to the surrounding epidermal cells, and covered by peltate trichomes. While the epidermal characteristics of D. brevifolia are similar to those of Bromeliaceae species, this species has made particular adaptations of leaf epidermis in response to its rheophytic environment.

  16. Towards a unified model for leaf trait and trait-environment relationships

    Science.gov (United States)

    Wang, H.; Harrison, S. P.; Prentice, I. C.; Peng, C.; Yang, Y.

    2016-12-01

    A widely accepted core set of leaf traits describes key aspects of plant function including the coupling among carbon, nitrogen and water cycles at the leaf, plant and ecosystem scales. Our current research focuses on two questions: (1) what dimensions of correlated variation among traits apply across all vascular plants irrespective of environment; (2) how, and to what extent, can variations in community mean values of leaf traits be predicted along environmental gradients? Based on a large quantitative trait data set covering the major environmental gradients across China, we are tackling these questions via two complementary approaches: multivariate analysis of trait-trait, trait-site, and trait-environment relationships, and the development of conceptual models and testable hypotheses for the dependencies of each trait on other traits and/or specific environmental predictors. Preliminary multivariate analyses suggest the existence of at least two independent axes of variation in leaf traits, and show robust relationships between trait syndromes and growing-season climate variables. A minimal conceptual model then considers nitrogen per unit leaf area (Narea) as a function of leaf mass per unit area (LMA) and carboxylation capacity (Vcmax); LMA as a function of irradiance, temperature and water and/or nutrient stress; Vcmax as a function of irradiance, temperature and the long-term ci:ca ratio (indexed by δ13C); and the ci:ca ratio as a function of vapour pressure deficit, temperature and atmospheric pressure. Each of these dependencies has support from observations, pointing the way towards a comprehensive set of equations to predict community-mean values of core traits in next-generation terrestrial ecosystem models.

  17. Leaf absorbance and photosynthesis

    Science.gov (United States)

    Schurer, Kees

    1994-01-01

    The absorption spectrum of a leaf is often thought to contain some clues to the photosynthetic action spectrum of chlorophyll. Of course, absorption of photons is needed for photosynthesis, but the reverse, photosynthesis when there is absorption, is not necessarily true. As a check on the existence of absorption limits we measured spectra for a few different leaves. Two techniques for measuring absorption have been used, viz. the separate determination of the diffuse reflectance and the diffuse transmittance with the leaf at a port of an integrating sphere and the direct determination of the non-absorbed fraction with the leaf in the sphere. In a cross-check both methods yielded the same results for the absorption spectrum. The spectrum of a Fuchsia leaf, covering the short-wave region from 350 to 2500 nm, shows a high absorption in UV, blue and red, the well known dip in the green and a steep fall-off at 700 nm. Absorption drops to virtually zero in the near infrared, with subsequent absorptions, corresponding to the water absorption bands. In more detailed spectra, taken at 5 nm intervals with a 5 nm bandwidth, differences in chlorophyll content show in the different depths of the dip around 550 nm and in a small shift of the absorption edge at 700 nm. Spectra for Geranium (Pelargonium zonale) and Hibiscus (with a higher chlorophyll content) show that the upper limit for photosynthesis can not be much above 700 nm. No evidence, however, is to be seen of a lower limit for photosynthesis and, in fact, some experiments down to 300 nm still did not show a decrease of the absorption although it is well recognized that no photosynthesis results with 300 nm wavelengths.

  18. Effects of terrestrial isopods (Crustacea: Oniscidea on leaf litter decomposition processes

    Directory of Open Access Journals (Sweden)

    Khaleid F. Abd El-Wakeil

    2015-03-01

    Full Text Available The leaf litter decomposition is carried out by the combined action of microorganisms and decomposer invertebrates such as earthworms, diplopods and isopods. The present work aimed to evaluate the impact of terrestrial isopod on leaf litter decomposition process. In Lab experimental food sources from oak and magnolia leaves litter were prepared. Air dried leaf litter were cut to 9 mm discs and sterilized in an autoclave then soaked in distilled water or water percolated through soil and left to decompose for 2, 4 and 6 weeks. 12 groups from two isopods species Porcellio scaber and Armadillidium vulgare, were prepared with each one containing 9 isopods. They were fed individually on the prepared food for 2 weeks. The prepared food differed in Carbon stable isotope ratio (δ13C, C%, N% and C/N ratios. At the end of the experiment, isopods were dissected and separated into gut, gut content and rest of the body. The δ13C for the prepared food, faecal pellets, remaining food, gut content, gut and rest of isopod were compared. The feeding activities of the two isopods were significantly different among isopods groups. Consumption and egestion ratios of magnolia leaf were higher than oak leaf. P. scaber consumed and egested litter higher than A. vulgare. The present results suggested that the impact of isopods and decomposition processes is species and litter specific.

  19. Leaf surface structures enable the endemic Namib desert grass Stipagrostis sabulicola to irrigate itself with fog water.

    Science.gov (United States)

    Roth-Nebelsick, A; Ebner, M; Miranda, T; Gottschalk, V; Voigt, D; Gorb, S; Stegmaier, T; Sarsour, J; Linke, M; Konrad, W

    2012-08-07

    The Namib grass Stipagrostis sabulicola relies, to a large degree, upon fog for its water supply and is able to guide collected water towards the plant base. This directed irrigation of the plant base allows an efficient and rapid uptake of the fog water by the shallow roots. In this contribution, the mechanisms for this directed water flow are analysed. Stipagrostis sabulicola has a highly irregular surface. Advancing contact angle is 98° ± 5° and the receding angle is 56° ± 9°, with a mean of both values of approximately 77°. The surface is thus not hydrophobic, shows a substantial contact angle hysteresis and therefore, allows the development of pinned drops of a substantial size. The key factor for the water conduction is the presence of grooves within the leaf surface that run parallel to the long axis of the plant. These grooves provide a guided downslide of drops that have exceeded the maximum size for attachment. It also leads to a minimum of inefficient drop scattering around the plant. The combination of these surface traits together with the tall and upright stature of S. sabulicola contributes to a highly efficient natural fog-collecting system that enables this species to thrive in a hyperarid environment.

  20. Leaf surface structures enable the endemic Namib desert grass Stipagrostis sabulicola to irrigate itself with fog water

    Science.gov (United States)

    Roth-Nebelsick, A.; Ebner, M.; Miranda, T.; Gottschalk, V.; Voigt, D.; Gorb, S.; Stegmaier, T.; Sarsour, J.; Linke, M.; Konrad, W.

    2012-01-01

    The Namib grass Stipagrostis sabulicola relies, to a large degree, upon fog for its water supply and is able to guide collected water towards the plant base. This directed irrigation of the plant base allows an efficient and rapid uptake of the fog water by the shallow roots. In this contribution, the mechanisms for this directed water flow are analysed. Stipagrostis sabulicola has a highly irregular surface. Advancing contact angle is 98° ± 5° and the receding angle is 56° ± 9°, with a mean of both values of approximately 77°. The surface is thus not hydrophobic, shows a substantial contact angle hysteresis and therefore, allows the development of pinned drops of a substantial size. The key factor for the water conduction is the presence of grooves within the leaf surface that run parallel to the long axis of the plant. These grooves provide a guided downslide of drops that have exceeded the maximum size for attachment. It also leads to a minimum of inefficient drop scattering around the plant. The combination of these surface traits together with the tall and upright stature of S. sabulicola contributes to a highly efficient natural fog-collecting system that enables this species to thrive in a hyperarid environment. PMID:22356817

  1. Rapid hydraulic recovery in Eucalyptus pauciflora after drought: linkages between stem hydraulics and leaf gas exchange.

    Science.gov (United States)

    Martorell, Sebastià; Diaz-Espejo, Antonio; Medrano, Hipólito; Ball, Marilyn C; Choat, Brendan

    2014-03-01

    In woody plants, photosynthetic capacity is closely linked to rates at which the plant hydraulic system can supply water to the leaf surface. Drought-induced embolism can cause sharp declines in xylem hydraulic conductivity that coincide with stomatal closure and reduced photosynthesis. Recovery of photosynthetic capacity after drought is dependent on restored xylem function, although few data exist to elucidate this coordination. We examined the dynamics of leaf gas exchange and xylem function in Eucalyptus pauciflora seedlings exposed to a cycle of severe water stress and recovery after re-watering. Stomatal closure and leaf turgor loss occurred at water potentials that delayed the extensive spread of embolism through the stem xylem. Stem hydraulic conductance recovered to control levels within 6 h after re-watering despite a severe drought treatment, suggesting an active mechanism embolism repair. However, stomatal conductance did not recover after 10 d of re-watering, effecting tighter control of transpiration post drought. The dynamics of recovery suggest that a combination of hydraulic and non-hydraulic factors influenced stomatal behaviour post drought. © 2013 John Wiley & Sons Ltd.

  2. Estimating leaf photosynthetic pigments information by stepwise multiple linear regression analysis and a leaf optical model

    Science.gov (United States)

    Liu, Pudong; Shi, Runhe; Wang, Hong; Bai, Kaixu; Gao, Wei

    2014-10-01

    Leaf pigments are key elements for plant photosynthesis and growth. Traditional manual sampling of these pigments is labor-intensive and costly, which also has the difficulty in capturing their temporal and spatial characteristics. The aim of this work is to estimate photosynthetic pigments at large scale by remote sensing. For this purpose, inverse model were proposed with the aid of stepwise multiple linear regression (SMLR) analysis. Furthermore, a leaf radiative transfer model (i.e. PROSPECT model) was employed to simulate the leaf reflectance where wavelength varies from 400 to 780 nm at 1 nm interval, and then these values were treated as the data from remote sensing observations. Meanwhile, simulated chlorophyll concentration (Cab), carotenoid concentration (Car) and their ratio (Cab/Car) were taken as target to build the regression model respectively. In this study, a total of 4000 samples were simulated via PROSPECT with different Cab, Car and leaf mesophyll structures as 70% of these samples were applied for training while the last 30% for model validation. Reflectance (r) and its mathematic transformations (1/r and log (1/r)) were all employed to build regression model respectively. Results showed fair agreements between pigments and simulated reflectance with all adjusted coefficients of determination (R2) larger than 0.8 as 6 wavebands were selected to build the SMLR model. The largest value of R2 for Cab, Car and Cab/Car are 0.8845, 0.876 and 0.8765, respectively. Meanwhile, mathematic transformations of reflectance showed little influence on regression accuracy. We concluded that it was feasible to estimate the chlorophyll and carotenoids and their ratio based on statistical model with leaf reflectance data.

  3. Environmental Monitoring, Water Quality - Total Maximum Daily Load (TMDL)

    Data.gov (United States)

    NSGIC Education | GIS Inventory — The Clean Water Act Section 303(d) establishes the Total Maximum Daily Load (TMDL) program. The purpose of the TMDL program is to identify sources of pollution and...

  4. Mosquitocidal and water purification properties of Cynodon dactylon, Aloe vera, Hemidesmus indicus and Coleus amboinicus leaf extracts against the mosquito vectors.

    Science.gov (United States)

    Arjunan, Nareshkumar; Murugan, Kadarkarai; Madhiyazhagan, Pari; Kovendan, Kalimuthu; Prasannakumar, Kanagarajan; Thangamani, Sundaram; Barnard, Donald R

    2012-04-01

    Ethanolic extracts of Cynodon dactylon, Aloe vera, Hemidesmus indicus and Coleus amboinicus were tested for their toxicity effect on the third-instar larvae of Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti. The leaves of C. dactylon, A. vera, H. indicus and C. amboinicus were collected from natural habitats (forests) in Western Ghats, Tamil Nadu, India. A total of 250 g of fresh, mature leaves were rinsed with distilled water and dried in shade. The dried leaves were put in Soxhlet apparatus and extract prepared using 100% ethanol for 72 h at 30-40°C. Dried residues were obtained from 100 g of extract evaporated to dryness in rotary vacuum evaporator. Larvicidal properties of ethanolic leaf extracts showed that the extracts are effective as mosquito control agents. The larval mortality was observed after 24 h exposure. No mortality was observed in the control. The median lethal concentration (LC(50)) values observed for the larvicidal activities are 0.44%, 0.51%, 0.59% and 0.68% for extracts of C. dactylon, A. vera, H. indicus and C. amboinicus, respectively. The observed mortality were statistically significant at P < 0.05 level. C. dactylon showed the highest mortality rate against the three species of mosquito larvae in laboratory and field. The selected plants were shown to exhibit water purification properties. Water quality parameters such as turbidity, pH and water clarity were analyzed in the water samples (pre-treatment and post-treatment of plant extracts) taken from the different breeding sites of mosquitoes. Water colour, turbidity and pH were reduced significantly after treatment with C. dactylon (13 HU, 31.5 mg/l and 6.9), H. indicus (13.8 HU, 33 mg/l and 7.1), A. vera (16 HU, 33.8 mg/l and 7.4) and C. amboinicus (21 HU, 35 mg/l and 7.5) extracts. The study proved that the extracts of C. dactylon, A. vera, H. indicus and C. amboinicus have both mosquitocidal and water sedimentation properties.

  5. Phytochemical and analgesic evaluation of methanol leaf extract of ...

    African Journals Online (AJOL)

    Phytochemical and analgesic evaluation of methanol leaf extract of ... Thirty minutes prior to intraperitoneal injection with 2 ml of 0.1% acetic acid, animals in groups ... (acetaminophen), aspirin and indomethacin while VII received saline water.

  6. Physiological response to drought in radiata pine: phytohormone implication at leaf level.

    Science.gov (United States)

    De Diego, N; Pérez-Alfocea, F; Cantero, E; Lacuesta, M; Moncaleán, P

    2012-04-01

    Pinus radiata D. Don is one of the most abundant species in the north of Spain. Knowledge of drought response mechanisms is essential to guarantee plantation survival under reduced water supply as predicted in the future. Tolerance mechanisms are being studied in breeding programs, because information on such mechanisms can be used for genotype selection. In this paper, we analyze the changes of leaf water potential, hydraulic conductance (K(leaf)), stomatal conductance and phytohormones under drought in P. radiata breeds (O1, O2, O3, O4, O5 and O6) from different climatology areas, hypothesizing that they could show variable drought tolerance. As a primary signal, drought decreased cytokinin (zeatin and zeatin riboside-Z + ZR) levels in needles parallel to K(leaf) and gas exchange. When Z + ZR decreased by 65%, indole-3-acetic acid (IAA) and abscisic acid (ABA) accumulation started as a second signal and increments were higher for IAA than for ABA. When plants decreased by 80%, Z + ZR and K(leaf) doubled their ABA and IAA levels, the photosystem II yield decreased and the electrolyte leakage increased. At the end of the drought period, less tolerant breeds increased IAA over 10-fold compared with controls. External damage also induced jasmonic acid accumulation in all breeds except in O5 (P. radiata var. radiata × var. cedrosensis), which accumulated salicylic acid as a defense mechanism. After rewatering, only the most tolerant plants recovered their K(leaf,) perhaps due to an IAA decrease and 1-aminocyclopropane-1-carboxylic acid maintenance. From all phytohormones, IAA was the most representative 'water deficit signal' in P. radiata.

  7. Is the lotus leaf superhydrophobic?

    Science.gov (United States)

    Cheng, Yang-Tse; Rodak, Daniel E.

    2005-04-01

    Superhydrophobic surfaces have important technical applications ranging from self-cleaning window glasses, paints, and fabrics to low-friction surfaces. The archetype superhydrophobic surface is that of the lotus leaf. When rain falls on lotus leaves, water beads up with a contact angle in the superhydrophobic range of about 160°. The water drops promptly roll off the leaves collecting dirt along the way. This lotus effect has, in recent years, stimulated much research effort worldwide in the fabrication of surfaces with superhydrophobicity. But, is the lotus surface truly superhydrophobic? This work shows that the lotus leaves can be either hydrophobic or hydrophilic, depending on how the water gets on to their surfaces. This finding has significant ramifications on how to make and use superhydrophobic surfaces.

  8. Restoration thinning and influence of tree size and leaf area to sapwood area ratio on water relations of Pinus ponderosa.

    Science.gov (United States)

    Simonin, K; Kolb, T E; Montes-Helu, M; Koch, G W

    2006-04-01

    Ponderosa pine (Pinus ponderosa Dougl. ex P. Laws) forest stand density has increased significantly over the last century (Covington et al. 1997). To understand the effect of increased intraspecific competition, tree size (height and diameter at breast height (DBH)) and leaf area to sapwood area ratio (A(L):A(S)) on water relations, we compared hydraulic conductance from soil to leaf (kl) and transpiration per unit leaf area (Q(L)) of ponderosa pine trees in an unthinned plot to trees in a thinned plot in the first and second years after thinning in a dense Arizona forest. We calculated kl and Q(L) based on whole- tree sap flux measured with heat dissipation sensors. Thinning increased tree predawn water potential within two weeks of treatment. Effects of thinning on kl and Q(L) depended on DBH, A(L):A(S) and drought severity. During severe drought in the first growing season after thinning, kl and Q(L) of trees with low A(L):A(S) (160-250 mm DBH; 9-11 m height) were lower in the thinned plot than the unthinned plot, suggesting a reduction in stomatal conductance (g(s)) or reduced sapwood specific conductivity (K(S)), or both, in response to thinning. In contrast kl and Q(L) were similar in the thinned plot and unthinned plot for trees with high A(L):A(S) (260-360 mm DBH; 13-16 m height). During non-drought periods, kl and Q(L) were greater in the thinned plot than in the unthinned plot for all but the largest trees. Contrary to previous studies of ponderosa pine, A(L):A(S) was positively correlated with tree height and DBH. Furthermore, kl and Q(L) showed a weak negative correlation with tree height and a strong negative correlation with A(S) and thus A(L):A(S) in both the thinned and unthinned plots, suggesting that trees with high A(L):A(S) had lower g(s). Our results highlight the important influence of stand competitive environment on tree-size-related variation in A(L):A(S) and the roles of A(L):A(S) and drought on whole-tree water relations in response to

  9. Evaluation of Cytotoxicity and Genotoxicity of Inula viscosa Leaf Extracts with Allium Test

    Directory of Open Access Journals (Sweden)

    Tülay Aşkin Çelik

    2010-01-01

    Full Text Available I. viscosa has been used for years in folk medicine for its anti-inflammatory, antipyretic, antiseptic, and paper antiphlogistic activities. In this study, cytotoxic and genotoxic effects of I. viscosa leaf extracts on the root meristem cells of Allium cepa have been examined. Onion bulbs were exposed to 2.5 mg/ml, 5 mg/ml, and 10 mg/ml concentrations of the extracts for macroscopic and microscopic analysis. Tap water has been used as a negative control and Ethyl methanesulfonate (EMS (2⋅10−2 M has been used as a positive control. The test concentrations have been determined according to doses which are recommended for use in alternative medicine. There has been statistically significant (P<.05 inhibition of root growth depending on concentration by the extracts when compared with the control groups. All the tested extracts have been observed to have cytotoxic effects on cell division in A. cepa. I. viscosa leaf extract induces the total number of chromosomal aberrations and micronuclei (MNC formations in A. cepa root tip cells significantly when compared with control groups. Also, this paper shows for the first time the induction of cell death, ghost cells, cells with membrane damage, and binucleated cells by extract treatment. These results suggest the cytotoxic and genotoxic effects of the I. viscosa leaf extracts on A. cepa.

  10. Regulation and acclimation of leaf gas exchange in a piñon-juniper woodland exposed to three different precipitation regimes.

    Science.gov (United States)

    Limousin, Jean-Marc; Bickford, Christopher P; Dickman, Lee T; Pangle, Robert E; Hudson, Patrick J; Boutz, Amanda L; Gehres, Nathan; Osuna, Jessica L; Pockman, William T; McDowell, Nate G

    2013-10-01

    Leaf gas-exchange regulation plays a central role in the ability of trees to survive drought, but forecasting the future response of gas exchange to prolonged drought is hampered by our lack of knowledge regarding potential acclimation. To investigate whether leaf gas-exchange rates and sensitivity to drought acclimate to precipitation regimes, we measured the seasonal variations of leaf gas exchange in a mature piñon-juniper Pinus edulis-Juniperus monosperma woodland after 3 years of precipitation manipulation. We compared trees receiving ambient precipitation with those in an irrigated treatment (+30% of ambient precipitation) and a partial rainfall exclusion (-45%). Treatments significantly affected leaf water potential, stomatal conductance and photosynthesis for both isohydric piñon and anisohydric juniper. Leaf gas exchange acclimated to the precipitation regimes in both species. Maximum gas-exchange rates under well-watered conditions, leaf-specific hydraulic conductance and leaf water potential at zero photosynthetic assimilation all decreased with decreasing precipitation. Despite their distinct drought resistance and stomatal regulation strategies, both species experienced hydraulic limitation on leaf gas exchange when precipitation decreased, leading to an intraspecific trade-off between maximum photosynthetic assimilation and resistance of photosynthesis to drought. This response will be most detrimental to the carbon balance of piñon under predicted increases in aridity in the southwestern USA. © 2013 John Wiley & Sons Ltd.

  11. Covariance of oxygen and hydrogen isotopic compositions in plant water: species effects

    International Nuclear Information System (INIS)

    Cooper, L.W.; DeNiro, M.J.

    1989-01-01

    Leaf water becomes enriched in the heavy isotopes of oxygen and hydrogen during evapotranspiration. The magnitude of the enrichment has been shown to be influenced by temperature and humidity, but the effects of species—specific factors on leaf water enrichment of D and 18 O have not been studied for different plants growing together. Accordingly, to learn whether leaf water enrichment patterns and processes for D and 18 O are different for individual species growing under the same environmental conditions we tested the proposal that leaf waters in plants with crassulacean acid metabolism (CAM) show higher slopes (m in the leaf water equation °D = m ° 18 O + b) than in C 3 plants. We determined the relationships between the stable hydrogen (°D) and oxygen (° 18 O) isotope ratios of leaf waters collected during the diurnal cycle of evapotranspiration for Yucca schidigera, Ephedra aspera, Agave deserti, Prunus ilicifolia, Yucca whipplei, Heteromeles arbutifolia, Dyckia fosteriana, Simmondsia chinensis, and Encelia farinosa growing at two sites in southern California. Slopes (m in the above leaf water equation) ranged from 1.50 to 3.21, compared to °8 for meteoric water, but differences in slope could not be attributed to carboxylation pathway (CAM vs. C 3 ) nor climate (coastal California vs. Sonoran Desert). Higher slopes were correlated with greater overall ranges of leaf water enrichment of D and 18 O. Water in plants with higher slopes also differed most from unaltered meteoric water. Leaf water isotope ratios in plants with lower slopes were better correlated with temperature and humidity. The findings indicate that m in the aforementioned equation is related to the overall residence time for water in the leaf and proportions of water subjected to repeated evapotranspiration enrichments of heavy isotopes

  12. Allometric relationships predicting foliar biomass and leaf area:sapwood area ratio from tree height in five Costa Rican rain forest species.

    Science.gov (United States)

    Calvo-Alvarado, J C; McDowell, N G; Waring, R H

    2008-11-01

    We developed allometric equations to predict whole-tree leaf area (A(l)), leaf biomass (M(l)) and leaf area to sapwood area ratio (A(l):A(s)) in five rain forest tree species of Costa Rica: Pentaclethra macroloba (Willd.) Kuntze (Fabaceae/Mim), Carapa guianensis Aubl. (Meliaceae), Vochysia ferru-gi-nea Mart. (Vochysiaceae), Virola koshnii Warb. (Myristicaceae) and Tetragastris panamensis (Engl.) Kuntze (Burseraceae). By destructive analyses (n = 11-14 trees per species), we observed strong nonlinear allometric relationships (r(2) > or = 0.9) for predicting A(l) or M(l) from stem diameters or A(s) measured at breast height. Linear relationships were less accurate. In general, A(l):A(s) at breast height increased linearly with tree height except for Penta-clethra, which showed a negative trend. All species, however, showed increased total A(l) with height. The observation that four of the five species increased in A(l):A(s) with height is consistent with hypotheses about trade--offs between morphological and anatomical adaptations that favor efficient water flow through variation in the amount of leaf area supported by sapwood and those imposed by the need to respond quickly to light gaps in the canopy.

  13. Leaf optical system modeled as a stochastic process. [solar radiation interaction with terrestrial vegetation

    Science.gov (United States)

    Tucker, C. J.; Garratt, M. W.

    1977-01-01

    A stochastic leaf radiation model based upon physical and physiological properties of dicot leaves has been developed. The model accurately predicts the absorbed, reflected, and transmitted radiation of normal incidence as a function of wavelength resulting from the leaf-irradiance interaction over the spectral interval of 0.40-2.50 micron. The leaf optical system has been represented as Markov process with a unique transition matrix at each 0.01-micron increment between 0.40 micron and 2.50 micron. Probabilities are calculated at every wavelength interval from leaf thickness, structure, pigment composition, and water content. Simulation results indicate that this approach gives accurate estimations of actual measured values for dicot leaf absorption, reflection, and transmission as a function of wavelength.

  14. Leaf size and leaf display of thirty-eight tropical tree species

    NARCIS (Netherlands)

    Poorter, L.; Rozendaal, D.M.A.

    2008-01-01

    Trees forage for light through optimal leaf display. Effective leaf display is determined by metamer traits (i.e., the internode, petiole, and corresponding leaf), and thus these traits strongly co-determine carbon gain and as a result competitive advantage in a light-limited environment. We

  15. Psidium guajava and Piper betle leaf extracts prolong vase life of cut carnation (Dianthus caryophyllus) flowers.

    Science.gov (United States)

    Rahman, M M; Ahmad, S H; Lgu, K S

    2012-01-01

    The effect of leaf extracts of Psidium guajava and Piper betle on prolonging vase life of cut carnation flowers was studied. "Carola" and "Pallas Orange" carnation flowers, at bud stage, were pulsed 24 hours with a floral preservative. Then, flowers were placed in a vase solution containing sprite and a "germicide" (leaf extracts of P. guajava and P. betle, 8-HQC, or a copper coin). Flowers treated with 8-HQC, copper coin, and leaf extracts had longer vase life, larger flower diameter, and higher rate of water uptake compared to control (tap water). The leaf extracts of P. guajava and P. betle showed highest antibacterial and antifungal activities compared to the other treatments. Both showed similar effects on flower quality as the synthetic germicide, 8-HQC. Therefore, these extracts are likely natural germicides to prolong vase life of cut flowers.

  16. Simultaneous minimizing monitor units and number of segments without leaf end abutment for segmental intensity modulated radiation therapy delivery

    International Nuclear Information System (INIS)

    Li Kaile; Dai Jianrong; Ma Lijun

    2004-01-01

    Leaf end abutment is seldom studied when delivering segmental intensity modulated radiation therapy (IMRT) fields. We developed an efficient leaf sequencing method to eliminate leaf end abutment for segmental IMRT delivery. Our method uses simple matrix and sorting operations to obtain a solution that simultaneously minimizes total monitor units and number of segments without leaf end abutment between segments. We implemented and demonstrated our method for multiple clinical cases. We compared the results of our method with the results from exhaustive search method. We found that our solution without leaf end abutment produced equivalent results to the unconstrained solutions in terms of minimum total monitor units and minimum number of leaf segments. We conclude that the leaf end abutment fields can be avoided without affecting the efficiency of segmental IMRT delivery. The major strength of our method is its simplicity and high computing speed. This potentially provides a useful means for generating segmental IMRT fields that require high spatial resolution or complex intensity distributions

  17. Evaluation of Methane from Sisal Leaf Residue and Palash Leaf Litter

    Science.gov (United States)

    Arisutha, S.; Baredar, P.; Deshpande, D. M.; Suresh, S.

    2014-12-01

    The aim of this study is to evaluate methane production from sisal leaf residue and palash leaf litter mixed with different bulky materials such as vegetable market waste, hostel kitchen waste and digested biogas slurry in a laboratory scale anaerobic reactor. The mixture was prepared with 1:1 proportion. Maximum methane content of 320 ml/day was observed in the case of sisal leaf residue mixed with vegetable market waste as the feed. Methane content was minimum (47 ml/day), when palash leaf litter was used as feed. This was due to the increased content of lignin and polyphenol in the feedstock which were of complex structure and did not get degraded directly by microorganisms. Sisal leaf residue mixtures also showed highest content of volatile fatty acids (VFAs) as compared to palash leaf litter mixtures. It was observed that VFA concentration in the digester first increased, reached maximum (when pH was minimum) and then decreased.

  18. Leaf appearance rate and final main stem leaf number as affected by temperature and photoperiod in cereals grown in Mediterranean environment

    Directory of Open Access Journals (Sweden)

    Ezio Riggi

    2017-09-01

    Full Text Available In the present study, a two-year field trial was carried out with the aim to evaluate daylength and air temperature effects on leaf appearance and related rates in two durum wheat (Triticum durum Desf., two bread wheat (Triticum aestivum L. and two barley (Hordeum vulgare L. cultivars, using six different sowing dates (SD. Significant effects of SD on final main stem leaf number (FLN, thermal leaf appearance rate (TLAR, daily leaf appearance rate (DLAR and phyllochron (PhL were found. Cultivars resulted inversely correlated to mean air temperature in the interval emergence - fifth leaf full expansion (E-V. Linear response of leaf number over days after sowing was shown for all SD and cultivars, with R2 higher than 0.95. FLN linearly decreased from the first to the last SD for durum wheat, while more variable behaviour was observed in bread wheat. TLAR and DLAR showed a linear increment of the rate from the first to the last SD in durum wheat, while did not for bread wheat and barley. PhL in durum wheat decreased from the first to the last SD. Barley and bread wheat showed the highest values on those SDs which did not reach flowering. The increase of TLAR was affected by photoperiod and photothermal units in durum wheat, while by temperatures only in barley and bread wheat. Present results might find practical application in the improvement of phenology simulation models for durum wheat, bread wheat and barley grown in Mediterranean area in absence of water and nutrient stress.

  19. Repeated Dose 28-Days Oral Toxicity Study of Carica papaya L. Leaf Extract in Sprague Dawley Rats

    Directory of Open Access Journals (Sweden)

    Hussin Muhammad

    2012-04-01

    Full Text Available Carica papaya L. leaves have been used in ethnomedicine for the treatment of fevers and cancers. Despite its benefits, very few studies on their potential toxicity have been described. The aim of the present study was to characterize the chemical composition of the leaf extract from ‘Sekaki’ C. papaya cultivar by UPLC-TripleTOF-ESI-MS and to investigate the sub-acute oral toxicity in Sprague Dawley rats at doses of 0.01, 0.14 and 2 g/kg by examining the general behavior, clinical signs, hematological parameters, serum biochemistry and histopathology changes. A total of twelve compounds consisting of one piperidine alkaloid, two organic acids, six malic acid derivatives, and four flavonol glycosides were characterized or tentatively identified in the C. papaya leaf extract. In the sub-acute study, the C. papaya extract did not cause mortality nor were treatment-related changes in body weight, food intake, water level, and hematological parameters observed between treatment and control groups. Some biochemical parameters such as the total protein, HDL-cholesterol, AST, ALT and ALP were elevated in a non-dose dependent manner. Histopathological examination of all organs including liver did not reveal morphological alteration. Other parameters showed non-significant differences between treatment and control groups. The present results suggest that C. papaya leaf extract at a dose up to fourteen times the levels employed in practical use in traditional medicine in Malaysia could be considered safe as a medicinal agent.

  20. CO2 and temperature effects on leaf area production in two annual plant species

    International Nuclear Information System (INIS)

    Ackerly, D.D.; Coleman, J.S.; Morse, S.R.; Bazzaz, F.A.

    1992-01-01

    The authors studied leaf area production in two annual plant species, Abutilon theophrasti and Amaranthus retroflexus, under three day/night temperature regimes and two concentrations of carbon dioxide. The production of whole-plant leaf area during the first 30 d of growth was analyzed in terms of the leaf initiation rate, leaf expansion, individual leaf area, and, in Amaranthus, production of branch leaves. Temperature and CO 2 influenced leaf area production through effects on the rate of development, determined by the production of nodes on the main stem, and through shifts in the relationship between whole-plant leaf area and the number of main stem nodes. In Abutilon, leaf initiation rate was highest at 38 degree, but area of individual leaves was greatest at 28 degree. Total leaf area was greatly reduced at 18 degree due to slow leaf initiation rates. Elevated CO 2 concentration increased leaf initiation rate at 28 degree, resulting in an increase in whole-part leaf area. In Amaranthus, leaf initiation rate increased with temperature, and was increased by elevated CO 2 at 28 degree. Individual leaf area was greatest at 28 degree, and was increased by elevated CO 2 at 28 degree but decreased at 38 degree. Branch leaf area displayed a similar response to CO 2 , butt was greater at 38 degree. Overall, wholeplant leaf area was slightly increased at 38 degree relative to 28 degree, and elevated CO 2 levels resulted in increased leaf area at 28 degree but decreased leaf area at 38 degree

  1. Discovering the Importance of Bi-directional Water Fluxes in Leaves

    Science.gov (United States)

    Kayler, Z. E.; Saurer, M.; Siegwolf, R.

    2007-12-01

    The stable isotope ratio 18O/16O is used for constraining climate change models, partitioning ecosystem water fluxes and for studies of plant ecophysiology. Leaf water enrichment is an essential starting point for each of these applications. In order to obtain a complete picture of the role leaf water plays, not only the 18O values from leaf water but also the signature of transpired water must be accurately predicted for plants under varying environmental conditions. We used a novel chamber approach using highly depleted water (-330 ‰) as a vapor source to leaves of the velvet bean (Mucuna pruriens). We used a Walz gas exchange system consisting of a chamber that is controlled for humidity, light, and temperature. Water and carbon dioxide fluxes were measured by an infrared gas analyzer and chamber vapor was collected in cold traps chilled to - 60°C. Three leaves were collected after 2 hours to insure isotopic steady-state followed by leaf water extraction and isotope analysis. From this experiment we were able to measure the outward flux of soil source water and the inward flux of ambient vapor over a range of environments that varied in relative humidity (80%, 45%, 20%), light (50, 1000 μmolm-2s-1) and CO2 (50, 800 ppm). Leaf water isotopic values were below the source water values reflecting the influx of the labeled vapor. The degree to which leaf water values were depleted was strongly related to the relative humidity. The Craig-Gordon model overestimated depletion of leaf water under high relative humidity and predictions were improved with the Péclet correction. However, our initial analysis indicates that these models may not fully account for stomatal conductance in predicting leaf water isotopic values.

  2. Adaptation of European beech (Fagus silvatica L.) to different ecological conditions: leaf size variation

    International Nuclear Information System (INIS)

    Barna, M.

    2004-01-01

    In beech trees, both leaf morphology and leaf area show considerable adaptation capabilities to the local radiation climate. The plants adapting to shade conditions create large leaf area with high chlorophyll concentration and high water content in the living tissues. On the other hand, the leaves of plants exposed to radiation of higher intensity have smaller area, several layers of mesophyll, thick epidermis and cuticle, higher dry weight, higher energy potential of the dry mass and several other characteristic properties

  3. Nutritional evaluation of bitter leaf meal ( Vernonia amygdalina ...

    African Journals Online (AJOL)

    Nutritional evaluation of bitter leaf meal ( Vernonia amygdalina ): effects on ... A total of 72 one-day-old broiler chicks of Abor-acre breed were used for the trial and ... reduced the level of cholesterol, triglyceride, glucose, low density lipoprotein, ...

  4. Monocot leaves are eaten less than dicot leaves in tropical lowland rain forests: correlations with toughness and leaf presentation

    DEFF Research Database (Denmark)

    Grubb, P.J.; Jackson, R.V.; Barberis, I.M.

    2008-01-01

    . It was hypothesized that (a) losses of leaf area to herbivorous invertebrates are generally greatest during leaf expansion and smaller for monocots than for dicots, and (b) where losses after expansion are appreciable any difference between monocots and dicots then is smaller than that found during expansion. Methods......: At six sites on four continents, estimates were made of lamina area loss from the four most recently mature leaves of focal monocots and of the nearest dicot shoot. Measurements of leaf mass per unit area, and the concentrations of water and nitrogen were made for many of the species. In Panama...... of leaf mass per unit area, or concentrations of water or nitrogen. At only one site was the increase in loss from first to fourth mature leaf significant (also large and the same in monocots and dicots), but the losses sustained during expansion were much smaller in the monocots. In the leaf-cutter ant...

  5. The global distribution of leaf chlorophyll content and seasonal controls on carbon uptake

    Science.gov (United States)

    Croft, H.; Chen, J. M.; Luo, X.; Bartlett, P. A.; Staebler, R. M.; He, L.; Mo, G.; Luo, S.; Simic, A.; Arabian, J.; He, Y.; Zhang, Y.; Beringer, J.; Hutley, L. B.; Noland, T. L.; Arellano, P.; Stahl, C.; Homolová, L.; Bonal, D.; Malenovský, Z.; Yi, Q.; Amiri, R.

    2017-12-01

    Leaf chlorophyll (ChlLeaf) is crucial to biosphere-atmosphere exchanges of carbon and water, and the functioning of terrestrial ecosystems. Improving the accuracy of modelled photosynthetic carbon uptake is a central priority for understanding ecosystem response to a changing climate. A source of uncertainty within gross primary productivity (GPP) estimates is the failure to explicitly consider seasonal controls on leaf photosynthetic potential. Whilst the inclusion of ChlLeafinto carbon models has shown potential to provide a physiological constraint, progress has been hampered by the absence of a spatially-gridded, global chlorophyll product. Here, we present the first spatially-continuous, global view of terrestrial ChlLeaf, at weekly intervals. Satellite-derived ChlLeaf was modelled using a physically-based radiative transfer modelling approach, with a two stage model inversion method. 4-Scale and SAIL canopy models were first used to model leaf-level reflectance from ENIVSAT MERIS 300m satellite data. The PROSPECT leaf model was then used to derive ChlLeaf from the modelled leaf reflectance. This algorithm was validated using measured ChlLeaf data from 248 measurements within 26 field locations, covering six plant functional types (PFTs). Modelled results show very good relationships with measured data, particularly for deciduous broadleaf forests (R2 = 0.67; pmake an important step towards improving the accuracy of global carbon budgets.

  6. Accumulation of Pb and Cu heavy metals in sea water, sediment, and leaf and root tissue of Enhalus sp. in the seagrass bed of Banten Bay

    Energy Technology Data Exchange (ETDEWEB)

    Fauziah, Faiza, E-mail: faiza.fauziah@gmail.com; Choesin, Devi N., E-mail: faiza.fauziah@gmail.com [School of Life Sciences and Technology, Institut Teknologi Bandung, Jalan Ganeca 10, Bandung 40132 (Indonesia)

    2014-03-24

    Banten Bay in Indonesia is a coastal area which has been highly affected by human activity. Previous studies have reported the presence of lead (Pb) and copper (Cu) heavy metals in the seawater of this area. This study was conducted to measure the accumulation of Pb and Cu in seawater, sediment, leaf tissue, and root tissue of the seagrass species Enhalus sp. Sampling was conducted at two observation stations in Banten Bay: Station 1 (St.1) was located closer to the coastline and to industrial plants as source of pollution, while Station 2 (St.2) was located farther away offshore. At each station, three sampling points were established by random sampling. Field sampling was conducted at two different dates, i.e., on 29 May 2012 and 30 June 2012. Samples were processed by wet ashing using concentrated HNO{sub 3} acid and measured using Atomic Absorption Spectrometry (AAS). Accumulation of Pb was only detected in sediment samples in St.1, while Cu was detected in all samples. Average concentrations of Cu in May were as follows: sediment St.1 = 0.731 ppm, sediment St.2 = 0.383 ppm, seawater St.1 = 0.163 ppm, seawater St.2 = 0.174 ppm, leaf St.1 = 0.102 ppm, leaf St.2 = 0.132 ppm, root St.1= 0.139 ppm, and root St.2 = 0.075 ppm. Average measurements of Cu in June were: sediment St.1 = 0.260 ppm, leaf St.1 = 0.335 ppm, leaf St.2 = 0.301 ppm, root St.1= 0.047 ppm, and root St.2 = 0.060 ppm. In June, Cu was undetected in St.2 sediment and seawater at both stations. In May, Cu concentration in seawater exceeded the maximum allowable threshold for water as determined by the Ministry of the Environment. Spatial and temporal variation in Pb and Cu accumulation were most probably affected by distance from source and physical conditions of the environment (e.g., water current and mixing)

  7. Phytochemical analysis and gastroprotective activity of an olive leaf extract

    Directory of Open Access Journals (Sweden)

    IVANA ARSIĆ

    2009-04-01

    Full Text Available Some medicinal features of olive leaf have been known for centuries. It has been traditionally used as an antimicrobial and to prevent and treat diabetes mellitus and heart disease. Whether olive leaf, a natural antioxidant, influences the gastric defense mechanism and exhibits gastroprotection against experimentally-induced gastric lesions remains unknown. In this study, the content of total phenols, total flavonoids and tannins in olive leaf extract (OLE were determined. Seven phenolic compounds were identified and quantified (oleuropein, caffeic acid, luteolin, luteolin-7-O-glucoside, apigenin-7-O-glucoside, quercetin, and chryseriol. Furthermore, the protective activity of the OLE in gastric mucosal injury induced by a corrosive concentration of ethanol was investigated. In relation to the control group, pretreatment with OLE (40, 80 and 120 mg kg-1 significantly (p < 0.001 attenuated the gastric lesions induced by absolute ethanol. The protective effect of the OLE was similar to that obtained with a reference drug, ranitidine. The results obtained indicate that OLE possesses significant gastroprotective activity, and that the presence of compounds with antioxidative properties would probably explain this effect.

  8. Elimination of {sup 137}Cs from trefoil (leaf and stem), ``Mitsuba``, cryptotaenia japonica hassk, boiled in a distilled and salted waters

    Energy Technology Data Exchange (ETDEWEB)

    Motegi, Misako; Miyake, Sadaaki; Ohsawa, Takashi; Nakazawa, Kiyoaki [Saitama Inst. of Public Health (Japan); Izumo, Yoshiro

    1999-07-01

    Elimination of {sup 137}Cs from highly accumulated trefoil (leaf and stem) through boiling in distilled and salted water were investigated in relation to study the effect of cooking and processing on biochemical states of radionuclides (RI) contaminating in foods. {sup 137}Cs was hardly eliminated from the trefoil immersed in a distilled water at room temperature (about 15degC) during 10 min. {sup 137}Cs was considerably eliminated from the trefoil when boiled in a distilled water, 0.3-3.0% salt concentration of the water and soy sauce: about 40-60% (after 2 min), 70-85% (5 min) and 80-90% (10 min), respectively. Elimination of {sup 137}Cs in the soy sauce (e.g. 77.0{+-}2.9%, at 1% salt concentration after 10 min) was restrictive comparing to that in the salt water (93.4{+-}2.3%). These results are expected to contribute to evaluate the radiation exposure to man when a boiled trefoil contaminating with {sup 137}Cs was ingested. (author)

  9. Effect of subchronic administration of ethanolic leaf extract of croton ...

    African Journals Online (AJOL)

    The biochemical effcts of ethanolic leaf extract of Croton zambesicus on serum alkaline phosphatase(SAP),aspartate aminotransferase (AST) ,alanine aminotransferase(ALT),serum total protein and albumin were studied.The levels of these enzymes and that of total protein and albumin in the extract treated rats were not ...

  10. Antioxidant effect of betel leaf extract on dry-cured fish

    OpenAIRE

    Kalaimani, N.; Muraleedharan, V.; Joseph, K.G.; Unnikrishnan Nair, T.S.

    1984-01-01

    The effect of betel leaf (Piper betle Linn.) extract on control of autoxidation of fat in dry fish has been studied. Oil sardine has been selected for experiments since it contains very high amount of fat. The treatments were given with 5% (w/v) betel leaf extract in water at different stages of salt curing. FFA, PV and TVN values of the samples were determined periodically to assess the keeping quality and autoxidation. The sample, prepared by dipping the fish in the extract immediately afte...

  11. Total mercury in water, sediments, and animals along the Indian Coast

    Digital Repository Service at National Institute of Oceanography (India)

    Sanzgiri, S.; Mesquita, A.; Kureishy, T.W.

    Total mercury (Hg) in water, sediments and animals along the coast of India is estimated. Water samples were collected on board of R.V. Gaveshani.The zooplankton samples were collected by Indian Ocean Standard Net and Heron Tranter nets of 500 mesh...

  12. Combined effects of leaf litter and soil microsite on decomposition process in arid rangelands.

    Science.gov (United States)

    Carrera, Analía Lorena; Bertiller, Mónica Beatriz

    2013-01-15

    The objective of this study was to analyze the combined effects of leaf litter quality and soil properties on litter decomposition and soil nitrogen (N) mineralization at conserved (C) and disturbed by sheep grazing (D) vegetation states in arid rangelands of the Patagonian Monte. It was hypothesized that spatial differences in soil inorganic-N levels have larger impact on decomposition processes of non-recalcitrant than recalcitrant leaf litter (low and high concentration of secondary compounds, respectively). Leaf litter and upper soil were extracted from modal size plant patches (patch microsite) and the associated inter-patch area (inter-patch microsite) in C and D. Leaf litter was pooled per vegetation state and soil was pooled combining vegetation state and microsite. Concentrations of N and secondary compounds in leaf litter and total and inorganic-N in soil were assessed at each pooled sample. Leaf litter decay and soil N mineralization at microsites of C and D were estimated in 160 microcosms incubated at field capacity (16 month). C soils had higher total N than D soils (0.58 and 0.41 mg/g, respectively). Patch soil of C and inter-patch soil of D exhibited the highest values of inorganic-N (8.8 and 8.4 μg/g, respectively). Leaf litter of C was less recalcitrant and decomposed faster than that of D. Non-recalcitrant leaf litter decay and induced soil N mineralization had larger variation among microsites (coefficients of variation = 25 and 41%, respectively) than recalcitrant leaf litter (coefficients of variation = 12 and 32%, respectively). Changes in the canopy structure induced by grazing disturbance increased leaf litter recalcitrance, and reduced litter decay and soil N mineralization, independently of soil N levels. This highlights the importance of the combined effects of soil and leaf litter properties on N cycling probably with consequences for vegetation reestablishment and dynamics, rangeland resistance and resilience with implications

  13. Effect of Different Levels of Artichoke (Cynara scolymus L. Leaf Powder on the Performance and Meat Quality of Japanese Quail

    Directory of Open Access Journals (Sweden)

    Abbasi F

    2014-12-01

    Full Text Available A total of 240 Japanese quail chicks (1 d old were used in a 42-d trial to study the effects of Artichoke leaf powder and vitamin E on growth performance and meat quality. This experiment was performed as a completely randomized design with 4 replicates of 15 quails in each, using a 4×2 factorial arrangement with diet and gender as the main effects. Four dietary treatments were formulated by addition of 2 levels (1.5 and 3 percent of Artichoke leaf powder and 300 mg/Kg vitamin E to the basal diet. Results showed that supplementing the basal diet with Artichoke leaf powder and vitamin E significantly affected growth performance at 21 d of age (P. Dietary treatments significantly affected 2-thiobarbituric acid-reactive substance (TBARS and water holding capacity (WHC values of breast meat (P. The value of TBARS in breast meat was not affected by dietary levels of Artichoke leaf powder, whereas the value decreased significantly by vitamin E treatment (P. Quails receiving 1.5 percent Artichoke leaf powder and 300 mg/Kg vitamin E had significantly lower breast meat WHC than those  receiving the basal diet (P. Breast meat crude fat and WHC were affected by gender (P. Dietary 3 percent Artichoke leaf powder increased the b* values of thigh meat compared with the control. The lightness of thigh and breast meat and also redness of thigh meat were affected by gender (P. In general, the results indicated that supplementation of diet by Artichoke leaf powder did not improve growth performance of quails, but may have a potential to improve the oxidative stability and meat quality.

  14. Assessment of hepatoprotective role of Eucalyptus tereticornis leaf extract in Rattus norvegicus after vanadium intoxication

    International Nuclear Information System (INIS)

    Saxena, Prabhu N.; Shukla, Aparna; Saxena, Nishi; Arya, Jyoti

    2010-01-01

    The protective effect of Eucalyptus tereticornis leaf extract and its potency has been compared with Liv.52 following V 2 O 5 , induced hepatotoxicity in albino rats. LD 50 estimated for V 2 O 5 , was 69.6 mg/kg b.wt. The administered doses of V 2 O 5 , were LD 50 /10 th for acute and 1/7 th , 1/14 th and 1/21 th of sublethal dose for subacute (7, 14 and 21 ds) respectively. Body weight, liver weight and hepatosomatic index were assessed. Hepatotoxicity was assessed in terms of hepatic total proteins, total lipids and total cholesterol. V 2 O 5 intoxication significantly increased liver weight, hepatosomatic index, total lipids and total cholesterol, while significantly decreased body weight and total proteins. Pretreatment with dose of 100 mg/kg b.wt of Eucalyptus tereticornis leaf extract and 0.125 ml/kg b.wt. of Liv.52 syrup restored the increased liver weight, hepatosomatic index, total lipids and total cholesterol and decreased parameters like body weight and total proteins toward normalcy. The results reveal that Eucalyptus tereticornis leaf extract modulates V 2 O 5 toxicity like well known hepatoprotectant, however the modulation is less than Liv.52. (author)

  15. Interactive effects of UV radiation and reduced precipitation on the seasonal leaf phenolic content/composition and the antioxidant activity of naturally growing Arbutus unedo plants.

    Science.gov (United States)

    Nenadis, Nikolaos; Llorens, Laura; Koufogianni, Agathi; Díaz, Laura; Font, Joan; Gonzalez, Josep Abel; Verdaguer, Dolors

    2015-12-01

    The effects of UV radiation and rainfall reduction on the seasonal leaf phenolic content/composition and antioxidant activity of the Mediterranean shrub Arbutus unedo were studied. Naturally growing plants of A. unedo were submitted to 97% UV-B reduction (UVA), 95% UV-A+UV-B reduction (UV0) or near-ambient UV levels (UVBA) under two precipitation regimes (natural rainfall or 10-30% rainfall reduction). Total phenol, flavonol and flavanol contents, levels of eight phenols and antioxidant activity [DPPH(●) radical scavenging and Cu (II) reducing capacity] were measured in sun-exposed leaves at the end of four consecutive seasons. Results showed a significant seasonal variation in the leaf content of phenols of A. unedo, with the lowest values found in spring and the highest in autumn and/or winter. Leaf ontogenetic development and/or a possible effect of low temperatures in autumn/winter may account for such findings. Regardless of the watering regime and the sampling date, plant exposure to UV-B radiation decreased the total flavanol content of leaves, while it increased the leaf content in quercitrin (the most abundant quercetin derivative identified). By contrast, UV-A radiation increased the leaf content of theogallin, a gallic acid derivative. Other phenolic compounds (two quercetin derivatives, one of them being avicularin, and one kaempferol derivative, juglanin), as well as the antioxidant activity of the leaves, showed different responses to UV radiation depending on the precipitation regime. Surprisingly, reduced rainfall significantly decreased the total amount of quantified quercetin derivatives as well as the DPPH scavenging activity in A. unedo leaves. To conclude, present findings indicate that leaves of A. unedo can be a good source of antioxidants throughout the year, but especially in autumn and winter. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Influence of spectral properties on cassava leaf development and ...

    African Journals Online (AJOL)

    sunny t

    2014-02-12

    Feb 12, 2014 ... changes in leaf spectral characteristics were studied using Digimizer ... main wavelengths used by plants (blue, green and red) with the blue being the most preferred. Total ...... differences observed allude to plant behavior.

  17. Leaf rust of cultivated barley: pathology and control.

    Science.gov (United States)

    Park, Robert F; Golegaonkar, Prashant G; Derevnina, Lida; Sandhu, Karanjeet S; Karaoglu, Haydar; Elmansour, Huda M; Dracatos, Peter M; Singh, Davinder

    2015-01-01

    Leaf rust of barley is caused by the macrocyclic, heteroecious rust pathogen Puccinia hordei, with aecia reported from selected species of the genera Ornithogalum, Leopoldia, and Dipcadi, and uredinia and telia occurring on Hordeum vulgare, H. vulgare ssp. spontaneum, Hordeum bulbosum, and Hordeum murinum, on which distinct parasitic specialization occurs. Although Puccinia hordei is sporadic in its occurrence, it is probably the most common and widely distributed rust disease of barley. Leaf rust has increased in importance in recent decades in temperate barley-growing regions, presumably because of more intensive agricultural practices. Although total crop loss does not occur, under epidemic conditions yield reductions of up to 62% have been reported in susceptible varieties. Leaf rust is primarily controlled by the use of resistant cultivars, and, to date, 21 seedling resistance genes and two adult plant resistance (APR) genes have been identified. Virulence has been detected for most seedling resistance genes but is unknown for the APR genes Rph20 and Rph23. Other potentially new sources of APR have been reported, and additivity has been described for some of these resistances. Approaches to achieving durable resistance to leaf rust in barley are discussed.

  18. Psidium guajava and Piper betle Leaf Extracts Prolong Vase Life of Cut Carnation (Dianthus caryophyllus Flowers

    Directory of Open Access Journals (Sweden)

    M. M. Rahman

    2012-01-01

    Full Text Available The effect of leaf extracts of Psidium guajava and Piper betle on prolonging vase life of cut carnation flowers was studied. “Carola” and “Pallas Orange” carnation flowers, at bud stage, were pulsed 24 hours with a floral preservative. Then, flowers were placed in a vase solution containing sprite and a “germicide” (leaf extracts of P. guajava and P. betle, 8-HQC, or a copper coin. Flowers treated with 8-HQC, copper coin, and leaf extracts had longer vase life, larger flower diameter, and higher rate of water uptake compared to control (tap water. The leaf extracts of P. guajava and P. betle showed highest antibacterial and antifungal activities compared to the other treatments. Both showed similar effects on flower quality as the synthetic germicide, 8-HQC. Therefore, these extracts are likely natural germicides to prolong vase life of cut flowers.

  19. Supplementation of Red Betel Leaf (Piper crocatum in Dairy Cattle Feed on Fermentation Characteristics by in Vitro

    Directory of Open Access Journals (Sweden)

    Caribu Hadi Prayitno

    2016-05-01

    Full Text Available The aim of this study was to assess the impact and efficiency of red betel leaf’s extract supplementation in the diet of dairy cattle on fermentation characteristics by in vitro.  The research method was experiment by using completely randomized design.  The treatments that were tested were R1: basal feed, R2:  R1 + 15 ppm of  red betel  leaf (Piper crocatum extract, R3: R1 + 30 ppm of  red betel leaf (Piper crocatum extract, R4: R1 + 45 ppm of red betel leaf (Piper crocatum extract, R5: R1 + 60 ppm of red betel leaf (Piper crocatum extract. The parameters measured in this study were (1Dry MatterDigestibility (DMD,(2Organic Matter Digestibility (OMD  (3 total gas production  (4 methane production (CH4 and (5  total Volatille Fatty Acid (VFA.  The data were analyzed using analysis of variance followed Orthogonal Polynomial Test.The results showed that the suplementation red batel extract in the diet of dairy cow was significant (P < 0.01 on DMD, OMD, total gas production, methane production (CH4  and total VFA.Orthogonal Polynomial test showed the effect of treatment on Dry MatterDigestibility (DMD, total gas and CH4 gas production were in the form of cubic curve, as well as Organic Matter Digestibility (OMD and Volatille Fatty Acid (VFA in the form of quadrate curvewith supplementation of red betel leaf.

  20. Estimating the Relative Water Content of Single Leaves from Optical Polarization Measurements

    Science.gov (United States)

    Vanderbilt, Vern; Daughtry, Craig; Dahlgren, Robert

    2016-01-01

    Remotely sensing the water status of plants and the water content of canopies remain long-term goals of remote sensing research. For monitoring canopy water status, existing approaches such as the Crop Water Stress Index and the Equivalent Water Thickness have limitations. The CWSI does not work well in humid regions, requires estimates of the vapor pressure deficit near the canopy during the remote sensing over-flight and, once stomata close, provides little information regarding the canopy water status. The EWI is based upon the physics of water-light interaction, not plant physiology. In this research, we applied optical polarization techniques to monitor the VISNIR light reflected from the leaf interior, R, as well as the leaf transmittance, T, as the relative water content (RWC) of corn (Zea mays) leaves decreased. Our results show that R and T both changed nonlinearly as each leaf dried, R increasing and T decreasing. Our results tie changes in the VISNIR R and T to leaf physiological changes linking the light scattered out of the drying leaf interior to its relative water content and to changes in leaf cellular structure and pigments. Our results suggest remotely sensing the physiological water status of a single leaf and perhaps of a plant canopy might be possible in the future. However, using our approach to estimate the water status of a leaf does not appear possible at present, because our results display too much variability that we do not yet understand.

  1. Effects of combination of leaf resources on competition in container mosquito larvae.

    Science.gov (United States)

    Reiskind, M H; Zarrabi, A A; Lounibos, L P

    2012-08-01

    Resource diversity is critical to fitness in many insect species, and may determine the coexistence of competitive species and the function of ecosystems. Plant material provides the nutritional base for numerous aquatic systems, yet the consequences of diversity of plant material have not been studied in aquatic container systems important for the production of mosquitoes. To address how diversity in leaf detritus affects container-inhabiting mosquitoes, we examined how leaf species affect competition between two container inhabiting mosquito larvae, Aedes aegypti and Aedes albopictus, that co-occur in many parts of the world. We tested the hypotheses that leaf species changes the outcome of intra- and interspecific competition between these mosquito species, and that combinations of leaf species affect competition in a manner not predictable based upon the response to each leaf species alone (i.e. the response to leaf combinations is non-additive). We find support for our first hypothesis that leaf species can affect competition, evidence that, in general, leaf combination alters competitive interactions, and no support that leaf combination impacts interspecific competition differently than intraspecific competition. We conclude that combinations of leaves increase mosquito production non-additively such that combinations of leaves act synergistically, in general, and result in higher total yield of adult mosquitoes in most cases, although certain leaf combinations for A. albopictus are antagonistic. We also conclude that leaf diversity does not have a different effect on interspecific competition between A. aegypti and A. albopictus, relative to intraspecific competition for each mosquito.

  2. Assessment of Toxicity Profile of Lasianthera Africana Leaf ...

    African Journals Online (AJOL)

    ALICE

    2015-04-15

    Apr 15, 2015 ... intraperitoneal, intravenous or intramuscular routes of .... Effect of oral administration of doses of Lasianthera africana leaf extract on body weight of normal rat ... drinking water and treated with metformin (anti-diabetic drug) at a dose level ... glucometer (One Touch Ultra 2 Blood Glucose Monitoring System,.

  3. Effect of Addition of Moringa Leaf By-Product (Leaf-Waste) on ...

    African Journals Online (AJOL)

    The effects of incorporation of Moringa leaf fibre (a by-product of leaf processing which contains 24% Crude Fibre by dry weight at 0, 5 and 10 % substitution of wheat flour in cookies was investigated. Three products containing wheat flour: Moringa leaf fibre ratios of 100:0, 95:5, and 90:10 respectively were prepared, and a ...

  4. Can tritiated water-dilution space accurately predict total body water in chukar partridges

    International Nuclear Information System (INIS)

    Crum, B.G.; Williams, J.B.; Nagy, K.A.

    1985-01-01

    Total body water (TBW) volumes determined from the dilution space of injected tritiated water have consistently overestimated actual water volumes (determined by desiccation to constant mass) in reptiles and mammals, but results for birds are controversial. We investigated potential errors in both the dilution method and the desiccation method in an attempt to resolve this controversy. Tritiated water dilution yielded an accurate measurement of water mass in vitro. However, in vivo, this method yielded a 4.6% overestimate of the amount of water (3.1% of live body mass) in chukar partridges, apparently largely because of loss of tritium from body water to sites of dissociable hydrogens on body solids. An additional source of overestimation (approximately 2% of body mass) was loss of tritium to the solids in blood samples during distillation of blood to obtain pure water for tritium analysis. Measuring tritium activity in plasma samples avoided this problem but required measurement of, and correction for, the dry matter content in plasma. Desiccation to constant mass by lyophilization or oven-drying also overestimated the amount of water actually in the bodies of chukar partridges by 1.4% of body mass, because these values included water adsorbed onto the outside of feathers. When desiccating defeathered carcasses, oven-drying at 70 degrees C yielded TBW values identical to those obtained from lyophilization, but TBW was overestimated (0.5% of body mass) by drying at 100 degrees C due to loss of organic substances as well as water

  5. Water requirement and total body water estimation as affected by species, pregnancy and lactation using tritiated water

    International Nuclear Information System (INIS)

    Kamal, T.H.; El Banna, I.M.; Ayad, M.A.; Kotby, E.A.

    1978-01-01

    Radiotracer dilution technique was used to determine total body water (TBW) and the water turnover rate (WTR) estimate of water requirements in water buffaloe, Red Dannish cattle, fat tailed Osemi sheep and Camellus Dromedarius. Water buffaloes were found to have highest TBW, followed by camels, sheep and cattle in a descending order. The WTR ranking was highest for sheep followed by water buffaloe endurance to heat was found inseperable to high water usage, while in camels, an intericate water retention mechanism help animals to thrive in deserts. Fat tailled Osemi sheep and cattle failed to cope with high environmental temperature resulting in temporary dehydration. TBW was 17% and 6% higher in pregnant cattle and sheep than non-pregnant animals respectively, while there was no observed change in pregnant buffaloes. Water retention of pregnant cattle was associated with an appriciable increase in WTR, which was not noticable in buffaloe or sheep. Lactating buffaloe have had a higher TBW and WTR than lactating cattle. Milk yield per day during the period of measurement was higher in buffalo than cattle. Wallowing of buffalo in water pools during grazing, represents a behavioural adaptation for life in hot regions, aside of tendency for higher WTR with concomitant water retention

  6. Optimal balance of water use efficiency and leaf construction cost with a link to the drought threshold of the desert steppe ecotone in northern China.

    Science.gov (United States)

    Wei, Haixia; Luo, Tianxiang; Wu, Bo

    2016-09-01

    In arid environments, a high nitrogen content per leaf area (Narea) induced by drought can enhance water use efficiency (WUE) of photosynthesis, but may also lead to high leaf construction cost (CC). Our aim was to investigate how maximizing Narea could balance WUE and CC in an arid-adapted, widespread species along a rainfall gradient, and how such a process may be related to the drought threshold of the desert-steppe ecotone in northern China. Along rainfall gradients with a moisture index (MI) of 0·17-0·41 in northern China and the northern Tibetan Plateau, we measured leaf traits and stand variables including specific leaf area (SLA), nitrogen content relative to leaf mass and area (Nmass, Narea) and construction cost (CCmass, CCarea), δ(13)C (indicator of WUE), leaf area index (LAI) and foliage N-pool across populations of Artemisia ordosica In samples from northern China, a continuous increase of Narea with decreasing MI was achieved by a higher Nmass and constant SLA (reduced LAI and constant N-pool) in high-rainfall areas (MI > 0·29), but by a lower SLA and Nmass (reduced LAI and N-pool) in low-rainfall areas (MI ≤ 0·29). While δ(13)C, CCmass and CCarea continuously increased with decreasing MI, the low-rainfall group had higher Narea and δ(13)C at a given CCarea, compared with the high-rainfall group. Similar patterns were also found in additional data for the same species in the northern Tibetan Plateau. The observed drought threshold where MI = 0·29 corresponded well to the zonal boundary between typical and desert steppes in northern China. Our data indicated that below a climatic drought threshold, drought-resistant plants tend to maximize their intrinsic WUE through increased Narea at a given CCarea, which suggests a linkage between leaf functional traits and arid vegetation zonation. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please

  7. Detritivores enhance the mobilization of {sup 137}Cs from leaf-litter

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Masashi; Suzuki, Takahiro [Community Ecology Lab., Biology Course, Faculty of Science, Chiba University, Chiba, 263-8522 (Japan); Ishii, Nobuyoshi [National Institute of Radiological Sciences, Chiba, 263-8555 (Japan); Ohte, Nobuhito [Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657 (Japan)

    2014-07-01

    A large amount of radioactive material was released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident after the disastrous earthquake and subsequent tsunami of March 2011. Since most of the Japanese land area is covered by forest ecosystems, {sup 137}Cs was mostly deposited and accumulated on the land surface of forest. The fate of radioactive materials accumulated on the leaf litters should be conscientiously monitored to understand the future distribution and the spread to the surrounding landscapes. Because the accident took place on 11 March 2011, just before the bud-break of deciduous trees, the {sup 137}Cs are highly accumulated on the surface of leaf litter on the forest floor. This accumulated {sup 137}Cs had transferred to higher trophic organisms mainly through the detritus food chain. However, on the litter surface, {sup 137}Cs considered to be strongly and immediately fixed and highly immobilized. Decomposition processes in the forest floor can re-mobilise the nutritional elements which are contained within detritus and make them available for the organisms. In the present study, the feeding effect of detritivore soil arthropods on the mobilization of {sup 137}Cs from leaf litter was experimentally examined. Furthermore, the effect of detritivores on the plant uptake of {sup 137}Cs was examined by small-scale nursery experiment. Decomposition experiment in the small microcosms was performed using a larvae of Trypoxylus dichotomus, whichis a detritivores feeding on dead plant materials such as wood debris and leaf litters. Contaminated leaf litters were collected in a forest of the Kami-Oguni River catchment in the northern part of Fukushima Prefecture. The leaf litters at A0 layers which are highly contaminated by {sup 137}Cs were utilized for the experiment. The contaminated leaf litter was fed to the larvae for ten days. The litter with larvae excreta was washed by 2 M KCl and deionized water. The {sup 137}Cs concentration was measured

  8. Cytotoxicity testing of aqueous extract of bitter leaf (Vernonia ...

    African Journals Online (AJOL)

    Cytotoxicity testing of aqueous extract of bitter leaf (Vernonia amygdalina Del) and sniper. 1000EC (2,3 ... man and animals.1 It is estimated that 80% of the popula- ..... evaluation of waste, surface and ground water quality using the Allium test ...

  9. Vapour pressure deficit during growth has little impact on genotypic differences of transpiration efficiency at leaf and whole-plant level: an example from Populus nigra L.

    Science.gov (United States)

    Rasheed, Fahad; Dreyer, Erwin; Richard, Béatrice; Brignolas, Franck; Brendel, Oliver; Le Thiec, Didier

    2015-04-01

    Poplar genotypes differ in transpiration efficiency (TE) at leaf and whole-plant level under similar conditions. We tested whether atmospheric vapour pressure deficit (VPD) affected TE to the same extent across genotypes. Six Populus nigra genotypes were grown under two VPD. We recorded (1) (13)C content in soluble sugars; (2) (18)O enrichment in leaf water; (3) leaf-level gas exchange; and (4) whole-plant biomass accumulation and water use. Whole-plant and intrinsic leaf TE and (13)C content in soluble sugars differed significantly among genotypes. Stomatal conductance contributed more to these differences than net CO2 assimilation rate. VPD increased water use and reduced whole-plant TE. It increased intrinsic leaf-level TE due to a decline in stomatal conductance. It also promoted higher (18)O enrichment in leaf water. VPD had no genotype-specific effect. We detected a deviation in the relationship between (13)C in leaf sugars and (13)C predicted from gas exchange and the standard discrimination model. This may be partly due to genotypic differences in mesophyll conductance, and to its lack of sensitivity to VPD. Leaf-level (13)C discrimination was a powerful predictor of the genetic variability of whole-plant TE irrespective of VPD during growth. © 2014 John Wiley & Sons Ltd.

  10. Global variability in leaf respiration in relation to climate and leaf traits

    Science.gov (United States)

    Atkin, Owen K.

    2015-04-01

    Leaf respiration plays a vital role in regulating ecosystem functioning and the Earth's climate. Because of this, it is imperative that that Earth-system, climate and ecosystem-level models be able to accurately predict variations in rates of leaf respiration. In the field of photosynthesis research, the F/vC/B model has enabled modellers to accurately predict variations in photosynthesis through time and space. By contrast, we lack an equivalent biochemical model to predict variations in leaf respiration. Consequently, we need to rely on phenomenological approaches to model variations in respiration across the Earth's surface. Such approaches require that we develop a thorough understanding of how rates of respiration vary among species and whether global environmental gradients play a role in determining variations in leaf respiration. Dealing with these issues requires that data sets be assembled on rates of leaf respiration in biomes across the Earth's surface. In this talk, I will use a newly-assembled global database on leaf respiration and associated traits (including photosynthesis) to highlight variation in leaf respiration (and the balance between respiration and photosynthesis) across global gradients in growth temperature and aridity.

  11. Effect of nitrogen supply on leaf appearance, leaf growth, leaf nitrogen economy and photosynthetic capacity in maize (Zea mays L.)

    NARCIS (Netherlands)

    Vos, J.; Putten, van der P.E.L.; Birch, C.J.

    2005-01-01

    Leaf area growth and nitrogen concentration per unit leaf area, Na (g m-2 N) are two options plants can use to adapt to nitrogen limitation. Previous work indicated that potato (Solanum tuberosum L.) adapts the size of leaves to maintain Na and photosynthetic capacity per unit leaf area. This paper

  12. Overproduction of abscisic acid in tomato increases transpiration efficiency and root hydraulic conductivity and influences leaf expansion.

    Science.gov (United States)

    Thompson, Andrew J; Andrews, John; Mulholland, Barry J; McKee, John M T; Hilton, Howard W; Horridge, Jon S; Farquhar, Graham D; Smeeton, Rachel C; Smillie, Ian R A; Black, Colin R; Taylor, Ian B

    2007-04-01

    Overexpression of genes that respond to drought stress is a seemingly attractive approach for improving drought resistance in crops. However, the consequences for both water-use efficiency and productivity must be considered if agronomic utility is sought. Here, we characterize two tomato (Solanum lycopersicum) lines (sp12 and sp5) that overexpress a gene encoding 9-cis-epoxycarotenoid dioxygenase, the enzyme that catalyzes a key rate-limiting step in abscisic acid (ABA) biosynthesis. Both lines contained more ABA than the wild type, with sp5 accumulating more than sp12. Both had higher transpiration efficiency because of their lower stomatal conductance, as demonstrated by increases in delta(13)C and delta(18)O, and also by gravimetric and gas-exchange methods. They also had greater root hydraulic conductivity. Under well-watered glasshouse conditions, mature sp5 plants were found to have a shoot biomass equal to the wild type despite their lower assimilation rate per unit leaf area. These plants also had longer petioles, larger leaf area, increased specific leaf area, and reduced leaf epinasty. When exposed to root-zone water deficits, line sp12 showed an increase in xylem ABA concentration and a reduction in stomatal conductance to the same final levels as the wild type, but from a different basal level. Indeed, the main difference between the high ABA plants and the wild type was their performance under well-watered conditions: the former conserved soil water by limiting maximum stomatal conductance per unit leaf area, but also, at least in the case of sp5, developed a canopy more suited to light interception, maximizing assimilation per plant, possibly due to improved turgor or suppression of epinasty.

  13. Results and Conclusions from the NASA Isokinetic Total Water Content Probe 2009 IRT Test

    Science.gov (United States)

    Reehorst, Andrew; Brinker, David

    2010-01-01

    The NASA Glenn Research Center has developed and tested a Total Water Content Isokinetic Sampling Probe. Since, by its nature, it is not sensitive to cloud water particle phase nor size, it is particularly attractive to support super-cooled large droplet and high ice water content aircraft icing studies. The instrument comprises the Sampling Probe, Sample Flow Control, and Water Vapor Measurement subsystems. Results and conclusions are presented from probe tests in the NASA Glenn Icing Research Tunnel (IRT) during January and February 2009. The use of reference probe heat and the control of air pressure in the water vapor measurement subsystem are discussed. Several run-time error sources were found to produce identifiable signatures that are presented and discussed. Some of the differences between measured Isokinetic Total Water Content Probe and IRT calibration seems to be caused by tunnel humidification and moisture/ice crystal blow around. Droplet size, airspeed, and liquid water content effects also appear to be present in the IRT calibration. Based upon test results, the authors provide recommendations for future Isokinetic Total Water Content Probe development.

  14. SU-F-T-350: Continuous Leaf Optimization (CLO) for IMRT Leaf Sequencing

    Energy Technology Data Exchange (ETDEWEB)

    Long, T; Chen, M; Jiang, S; Lu, W [UT Southwestern Medical Center, Dallas, TX (United States)

    2016-06-15

    Purpose: To study a new step-and-shoot IMRT leaf sequencing model that avoids the two main pitfalls of conventional leaf sequencing: (1) target fluence being stratified into a fixed number of discrete levels and/or (2) aperture leaf positions being restricted to a discrete set of locations. These assumptions induce error into the sequence or reduce the feasible region of potential plans, respectively. Methods: We develop a one-dimensional (single leaf pair) methodology that does not make assumptions (1) or (2) that can be easily extended to a multi-row model. The proposed continuous leaf optimization (CLO) methodology takes in an existing set of apertures and associated intensities, or solution “seed,” and improves the plan without the restrictiveness of 1or (2). It then uses a first-order descent algorithm to converge onto a locally optimal solution. A seed solution can come from models that assume (1) and (2), thus allowing the CLO model to improve upon existing leaf sequencing methodologies. Results: The CLO model was applied to 208 generated target fluence maps in one dimension. In all cases for all tested sequencing strategies, the CLO model made improvements on the starting seed objective function. The CLO model also was able to keep MUs low. Conclusion: The CLO model can improve upon existing leaf sequencing methods by avoiding the restrictions of (1) and (2). By allowing for more flexible leaf positioning, error can be reduced when matching some target fluence. This study lays the foundation for future models and solution methodologies that can incorporate continuous leaf positions explicitly into the IMRT treatment planning model. Supported by Cancer Prevention & Research Institute of Texas (CPRIT) - ID RP150485.

  15. Evaluation of banana hybrids for tolerance to black leaf streak (Mycosphaerella fijiensis Morelet) in Puerto Rico

    Science.gov (United States)

    In Puerto Rico, bananas (including plantains) are important agricultural commodities; their combined production totaled 133,500 tons in 2008. Black leaf streak (BLS) and Sigatoka leaf spot diseases, caused by Mycosphaerella fijiensis and M. musicola, respectively, are responsible for significant los...

  16. Evidence for mild sediment Pb contamination affecting leaf-litter decomposition in a lake.

    Science.gov (United States)

    Oguma, Andrew Y; Klerks, Paul L

    2015-08-01

    Much work has focused on the effects of metal-contaminated sediment on benthic community structure, but effects on ecosystem functions have received far less attention. Decomposition has been widely used as an integrating metric of ecosystem function in lotic systems, but not for lentic ones. We assessed the relationship between low-level sediment lead (Pb) contamination and leaf-litter decomposition in a lentic system. We measured 30-day weight loss in 30 litter-bags that were deployed along a Pb-contamination gradient in a cypress-forested lake. At each deployment site we also quantified macrobenthos abundance, dissolved oxygen, water depth, sediment organic content, sediment silt/clay content, and both total sediment and porewater concentrations of Cd, Cu, Ni, Pb and Zn. Principal components (PC) analysis revealed a negative relationship between Pb concentration and benthic macroinvertebrate abundance, and this covariation dominated the first PC axis (PC1). Subsequent correlation analyses revealed a negative relationship between PC1 and percent leaf-litter loss. Our results indicate that leaf-litter decomposition was related to sediment Pb and benthic macroinvertebrate abundance. They also showed that ecosystem function may be affected even where sediment Pb concentrations are mostly below threshold-effects sediment quality guidelines--a finding with potential implications for sediment risk assessment. Additionally, the litter-bag technique used in this study showed promise as a tool in risk assessments of metal-contaminated sediments in lentic systems.

  17. Remote sensing of LAI, chlorophyll and leaf nitrogen pools of crop- and grasslands in five European landscapes

    DEFF Research Database (Denmark)

    Bøgh, Eva; Houborg, R; Bienkowski, J

    2013-01-01

    Leaf nitrogen and leaf surface area influence the exchange of gases between terrestrial ecosystems and the atmosphere, and they play a significant role in the global cycles of carbon, nitrogen and water. Remote sensing data from satellites can be used to estimate leaf area index (LAI), leaf......). Predictabilities of SVIs and REGFLEC simulations generally improved when constrained to single land use categories (wheat, maize, barley, grass) across the European landscapes, reflecting sensitivity to canopy structures. Predictability further improved when constrained to local (10 × 10 km2) landscapes, thereby...

  18. Identification of Alfalfa Leaf Diseases Using Image Recognition Technology.

    Directory of Open Access Journals (Sweden)

    Feng Qin

    Full Text Available Common leaf spot (caused by Pseudopeziza medicaginis, rust (caused by Uromyces striatus, Leptosphaerulina leaf spot (caused by Leptosphaerulina briosiana and Cercospora leaf spot (caused by Cercospora medicaginis are the four common types of alfalfa leaf diseases. Timely and accurate diagnoses of these diseases are critical for disease management, alfalfa quality control and the healthy development of the alfalfa industry. In this study, the identification and diagnosis of the four types of alfalfa leaf diseases were investigated using pattern recognition algorithms based on image-processing technology. A sub-image with one or multiple typical lesions was obtained by artificial cutting from each acquired digital disease image. Then the sub-images were segmented using twelve lesion segmentation methods integrated with clustering algorithms (including K_means clustering, fuzzy C-means clustering and K_median clustering and supervised classification algorithms (including logistic regression analysis, Naive Bayes algorithm, classification and regression tree, and linear discriminant analysis. After a comprehensive comparison, the segmentation method integrating the K_median clustering algorithm and linear discriminant analysis was chosen to obtain lesion images. After the lesion segmentation using this method, a total of 129 texture, color and shape features were extracted from the lesion images. Based on the features selected using three methods (ReliefF, 1R and correlation-based feature selection, disease recognition models were built using three supervised learning methods, including the random forest, support vector machine (SVM and K-nearest neighbor methods. A comparison of the recognition results of the models was conducted. The results showed that when the ReliefF method was used for feature selection, the SVM model built with the most important 45 features (selected from a total of 129 features was the optimal model. For this SVM model, the

  19. Identification of Alfalfa Leaf Diseases Using Image Recognition Technology

    Science.gov (United States)

    Qin, Feng; Liu, Dongxia; Sun, Bingda; Ruan, Liu; Ma, Zhanhong; Wang, Haiguang

    2016-01-01

    Common leaf spot (caused by Pseudopeziza medicaginis), rust (caused by Uromyces striatus), Leptosphaerulina leaf spot (caused by Leptosphaerulina briosiana) and Cercospora leaf spot (caused by Cercospora medicaginis) are the four common types of alfalfa leaf diseases. Timely and accurate diagnoses of these diseases are critical for disease management, alfalfa quality control and the healthy development of the alfalfa industry. In this study, the identification and diagnosis of the four types of alfalfa leaf diseases were investigated using pattern recognition algorithms based on image-processing technology. A sub-image with one or multiple typical lesions was obtained by artificial cutting from each acquired digital disease image. Then the sub-images were segmented using twelve lesion segmentation methods integrated with clustering algorithms (including K_means clustering, fuzzy C-means clustering and K_median clustering) and supervised classification algorithms (including logistic regression analysis, Naive Bayes algorithm, classification and regression tree, and linear discriminant analysis). After a comprehensive comparison, the segmentation method integrating the K_median clustering algorithm and linear discriminant analysis was chosen to obtain lesion images. After the lesion segmentation using this method, a total of 129 texture, color and shape features were extracted from the lesion images. Based on the features selected using three methods (ReliefF, 1R and correlation-based feature selection), disease recognition models were built using three supervised learning methods, including the random forest, support vector machine (SVM) and K-nearest neighbor methods. A comparison of the recognition results of the models was conducted. The results showed that when the ReliefF method was used for feature selection, the SVM model built with the most important 45 features (selected from a total of 129 features) was the optimal model. For this SVM model, the

  20. Covariance of oxygen and hydrogen isotopic composition in plant water: Species effects

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, L.W.; DeNiro, M.J. (Univ. of California, Los Angeles (United States))

    1989-12-01

    Leaf water becomes enriched in the heavy isotopes of oxygen and hydrogen during evapotranspiration. The magnitude of the enrichment has been shown to be influenced by temperature and humidity, but the effects of species-specific factors on leaf water enrichment of D and {sup 18}O have not been studied for different plants growing together. To learn whether leaf water enrichment patterns and processes for D and {sup 18}O are different for individual species growing under the same environmental conditions the authors tested the proposal that leaf waters in plants with crassulacean acid metabolism (CAM) show high sloped (m in the leaf water equation {delta}D = m {delta}{sup 18}O + b) than in C{sub 3} plants. They determined the relationships between the stable hydrogen ({delta}D) and oxygen ({delta}{sup 18}O) isotope ratios of leaf waters collected during the diurnal cycle of evapotranspiration for Yucca schidigera, Ephedra aspera, Agave deserti, Prunus ilicifolia, Yucca whipplei, Heteromeles arbutifolia, Dyckia fosteriana, Simmondsia chinensis, and Encelia farinosa growing at two sites in southern California. The findings indicate that m in the aforementioned equation is related to the overall residence time for water in the leaf and proportions of water subjected to repeated evapotranspiration enrichments of heavy isotopes.

  1. Antimicrobial compounds from leaf extracts of Jatropha curcas, Psidium guajava, and Andrographis paniculata.

    Science.gov (United States)

    Rahman, M M; Ahmad, S H; Mohamed, M T M; Ab Rahman, M Z

    2014-01-01

    The present research was conducted to discover antimicrobial compounds in methanolic leaf extracts of Jatropha curcas and Andrographis paniculata and ethanolic leaf extract of Psidium guajava and the effectiveness against microbes on flower preservative solution of cut Mokara Red orchid flowers was evaluated. The leaves were analyzed using gas chromatography-mass spectrometry. A total of nine, 66, and 29 compounds were identified in J. curcas, P. guajava, and A. paniculata leaf extracts, with five (88.18%), four (34.66%), and three (50.47%) having unique antimicrobial compounds, respectively. The experimental design on vase life was conducted using a completely randomized design with 10 replications. The flower vase life was about 6 days in the solution containing the P. guajava and A. paniculata leaf extracts at 15 mg/L. Moreover, solution with leaf extracts of A. paniculata had the lowest bacterial count compared to P. guajava and J. curcas. Thus, these leaf extracts revealed the presence of relevant antimicrobial compounds. The leaf extracts have the potential as a cut flower solution to minimize microbial populations and extend flower vase life. However, the activities of specific antimicrobial compounds and double or triple combination leaf extracts to enhance the effectiveness to extend the vase life need to be tested.

  2. Combined preharvest and postharvest treatments affect rapid leaf wilting in Bouvardia cut flowers

    NARCIS (Netherlands)

    Schouten, Rob E.; Dien, van Luka; Shahin, Arwa; Heimovaara, Sjoukje; Meeteren, van Uulke; Verdonk, Julian C.

    2018-01-01

    Bouvardia is an ornamental shrub, commercially cultivated as flowering stem. Occasionally, negative water balance, which leads to rapid leaf wilting, ends vase life immediately. This work studies the effect of preharvest and postharvest conditions on vase life, water uptake and transpiration.

  3. Water stress drastically reduces root growth and inulin yield in Cichorium intybus (var. sativum) independently of photosynthesis

    Science.gov (United States)

    Vandoorne, B.; Mathieu, A.-S.; Van den Ende, W.; Vergauwen, R.; Périlleux, C.; Javaux, M.; Lutts, S.

    2012-01-01

    Root chicory (Cichorium intybus var. sativum) is a cash crop cultivated for inulin production in Western Europe. This plant can be exposed to severe water stress during the last 3 months of its 6-month growing period. The aim of this study was to quantify the effect of a progressive decline in water availability on plant growth, photosynthesis, and sugar metabolism and to determine its impact on inulin production. Water stress drastically decreased fresh and dry root weight, leaf number, total leaf area, and stomatal conductance. Stressed plants, however, increased their water-use efficiency and leaf soluble sugar concentration, decreased the shoot-to-root ratio and lowered their osmotic potential. Despite a decrease in photosynthetic pigments, the photosynthesis light phase remained unaffected under water stress. Water stress increased sucrose phosphate synthase activity in the leaves but not in the roots. Water stress inhibited sucrose:sucrose 1-fructosyltransferase and fructan:fructan 1 fructosyltransferase after 19 weeks of culture and slightly increased fructan 1-exohydrolase activity. The root inulin concentration, expressed on a dry-weight basis, and the mean degree of polymerization of the inulin chain remained unaffected by water stress. Root chicory displayed resistance to water stress, but that resistance was obtained at the expense of growth, which in turn led to a significant decrease in inulin production. PMID:22577185

  4. Effect of Wind on the Relation of Leaf N, P Stoichiometry with Leaf Morphology in Quercus Species

    Directory of Open Access Journals (Sweden)

    Peng Zhang

    2018-02-01

    Full Text Available Leaf nitrogen (N and phosphorus (P stoichiometry correlates closely to leaf morphology, which is strongly impacted by wind at multiple scales. However, it is not clear how leaf N, P stoichiometry and its relationship to leaf morphology changes with wind load. We determined the leaf N and P concentrations and leaf morphology—including specific leaf area (SLA and leaf dissection index (LDI—for eight Quercus species under a simulated wind load for seven months. Leaf N and P concentrations increased significantly under these conditions for Quercus acutissima, Quercus rubra, Quercus texana, and Quercus palustris—which have elliptic leaves—due to their higher N, P requirements and a resultant leaf biomass decrease, which is a tolerance strategy for Quercus species under a wind load. Leaf N:P was relatively stable under wind for all species, which supports stoichiometric homeostasis. Leaf N concentrations showed a positive correlation to SLA, leaf N and P concentrations showed positive correlations to LDI under each wind treatment, and the slope of correlations was not affected by wind, which indicates synchronous variations between leaf stoichiometry and leaf morphology under wind. However, the intercept of correlations was affected by wind, and leaf N and P use efficiency decreased under the wind load, which suggests that the Quercus species changes from “fast investment-return” in the control to “slow investment-return” under windy conditions. These results will be valuable to understanding functional strategies for plants under varying wind loads, especially synchronous variations in leaf traits along a wind gradient.

  5. Response Surface Optimized Extraction of Total Triterpene Acids ...

    African Journals Online (AJOL)

    Purpose: To optimize extraction of total triterpene acids from loquat leaf and evaluate their in vitro antioxidant activities. Methods: The independent variables were ethanol concentration, extraction time, and solvent ratio, while the dependent variable was content of total triterpene acids. Composite design and response ...

  6. Infidelity in the outback: climate signal recorded in Δ18O of leaf but not branch cellulose of eucalypts across an Australian aridity gradient.

    Science.gov (United States)

    Cheesman, Alexander W; Cernusak, Lucas A

    2017-05-01

    The isotopic composition of leaf water in terrestrial plants is highly dependent upon a plant's environment. This isotopic signature can become integrated into organic molecules, allowing the isotopic composition of biomarkers such as cellulose to be used as sensitive paleo and climatic proxies. However, the mechanisms by which cellulose isotopic composition reflect environmental conditions are complex, and may vary between leaf and woody tissues. To date few empirical tests have been made on the relative roles of leaf-water enrichment and source water on the isotopic composition of leaf and wood cellulose within the same plant. Here, we study both leaf and branch wood cellulose, as well as xylem/source water of eucalypts across a 900 km aridity gradient in NE Australia. Across 11 sites, spanning average annual precipitation of 235-1400 mm and average relative humidity of 33-70%, we found a strong and consistent trend in leaf cellulose. However, once the effect of altered source water was considered we found wood cellulose to show no trend across this environmental gradient. We consider potential mechanisms that could explain the 'damping' of a climatic signal within wood cellulose and consider the implication and limitations on the use of tree-ring cellulose as a climate proxy. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Impacts of leaf age and heat stress duration on photosynthetic gas exchange and foliar nonstructural carbohydrates in Coffea arabica.

    Science.gov (United States)

    Marias, Danielle E; Meinzer, Frederick C; Still, Christopher

    2017-02-01

    Given future climate predictions of increased temperature, and frequency and intensity of heat waves in the tropics, suitable habitat to grow ecologically, economically, and socially valuable Coffea arabica is severely threatened. We investigated how leaf age and heat stress duration impact recovery from heat stress in C. arabica . Treated plants were heated in a growth chamber at 49°C for 45 or 90 min. Physiological recovery was monitored in situ using gas exchange, chlorophyll fluorescence (the ratio of variable to maximum fluorescence, F V / F M ), and leaf nonstructural carbohydrate (NSC) on mature and expanding leaves before and 2, 15, 25, and 50 days after treatment. Regardless of leaf age, the 90-min treatment resulted in greater F V / F M reduction 2 days after treatment and slower recovery than the 45-min treatment. In both treatments, photosynthesis of expanding leaves recovered more slowly than in mature leaves. Stomatal conductance ( g s ) decreased in expanding leaves but did not change in mature leaves. These responses led to reduced intrinsic water-use efficiency with increasing heat stress duration in both age classes. Based on a leaf energy balance model, aftereffects of heat stress would be exacerbated by increases in leaf temperature at low g s under full sunlight where C. arabica is often grown, but also under partial sunlight. Starch and total NSC content of the 45-min group significantly decreased 2 days after treatment and then accumulated 15 and 25 days after treatment coinciding with recovery of photosynthesis and F V / F M . In contrast, sucrose of the 90-min group accumulated at day 2 suggesting that phloem transport was inhibited. Both treatment group responses contrasted with control plant total NSC and starch, which declined with time associated with subsequent flower and fruit production. No treated plants produced flowers or fruits, suggesting that short duration heat stress can lead to crop failure.

  8. Differences in the environmental control of leaf senescence of four Quercus species coexisting in a Mediterranean environment

    Directory of Open Access Journals (Sweden)

    Teresa del Río-García

    2015-08-01

    Full Text Available Aims of study: Our aim is to check the effect of different environmental factors on the leaf senescence of four Quercus species with different leaf longevities, to help us better understand the implications of climate change on leaf demography. Area of study: The study was carried out in two sites of the province of Salamanca (central-western Spain, both sites showing differences in their temperatures and soil water availability. Material and Methods: Over four years (2007-2010 we monitored the number of leaves of the different cohorts labelled on five specimens of each species at both sites to elaborate life-tables and calculate mortality rates. Mortality rates were then related to several other variables measured during the same period: air temperature, soil water availability, precipitation, predawn water potentials (Ψpd and leaf N resorption. Main results: In the two deciduous species maximum daily temperatures and the time during which their values remain above a certain threshold (between 11 and 12ºC of maximum daily temperature are the main factors controlling the timing of leaf abscission. In the evergreen species abscission of old leaves showed no relationship with the environmental factors analyzed. By contrast, mortality rates of old leaves were related to seasonal N resorption values, with the maximum mortality of old leaves coinciding in time with the maximum withdrawal of N from shed leaves and also with the emergence of the new leaf cohort. Research highlights: The increase in the duration of the leaves of the two deciduous species, as a result of the delayed senescence by warmer autumnal temperatures, could contribute to reducing the differences in the length of the productive leaf life with respect to the evergreen species. This could improve the competitive capacity of deciduous species as opposed to that of evergreen species, and thus alter their respective distribution patterns.

  9. Drought limitations to leaf-level gas exchange: results from a model linking stomatal optimization and cohesion-tension theory.

    Science.gov (United States)

    Novick, Kimberly A; Miniat, Chelcy F; Vose, James M

    2016-03-01

    We merge concepts from stomatal optimization theory and cohesion-tension theory to examine the dynamics of three mechanisms that are potentially limiting to leaf-level gas exchange in trees during drought: (1) a 'demand limitation' driven by an assumption of optimal stomatal functioning; (2) 'hydraulic limitation' of water movement from the roots to the leaves; and (3) 'non-stomatal' limitations imposed by declining leaf water status within the leaf. Model results suggest that species-specific 'economics' of stomatal behaviour may play an important role in differentiating species along the continuum of isohydric to anisohydric behaviour; specifically, we show that non-stomatal and demand limitations may reduce stomatal conductance and increase leaf water potential, promoting wide safety margins characteristic of isohydric species. We used model results to develop a diagnostic framework to identify the most likely limiting mechanism to stomatal functioning during drought and showed that many of those features were commonly observed in field observations of tree water use dynamics. Direct comparisons of modelled and measured stomatal conductance further indicated that non-stomatal and demand limitations reproduced observed patterns of tree water use well for an isohydric species but that a hydraulic limitation likely applies in the case of an anisohydric species. Published 2015. This article is a US Government work and is in the public domain in the USA.

  10. Rates of nocturnal transpiration in two evergreen temperate woodland species with differing water-use strategies.

    Science.gov (United States)

    Zeppel, Melanie; Tissue, David; Taylor, Daniel; Macinnis-Ng, Catriona; Eamus, Derek

    2010-08-01

    Nocturnal fluxes may be a significant factor in the annual water budget of forested ecosystems. Here, we assessed sap flow in two co-occurring evergreen species (Eucalyptus parramattensis and Angophora bakeri) in a temperate woodland for 2 years in order to quantify the magnitude of seasonal nocturnal sap flow (E(n)) under different environmental conditions. The two species showed different diurnal water relations, demonstrated by different diurnal curves of stomatal conductance, sap flow and leaf water potential. The relative influence of several microclimatic variables, including wind speed (U), vapour pressure deficit (D), the product of U and D (UD) and soil moisture content, were quantified. D exerted the strongest influence on E(n) (r² = 0.59-0.86), soil moisture content influenced E(n) when D was constant, but U and UD did not generally influence E(n). In both species, cuticular conductance (G(c)) was a small proportion of total leaf conductance (G(s)) and was not a major pathway for E(n). We found that E(n) was primarily a function of transpiration from the canopy rather than refilling of stem storage, with canopy transpiration accounting for 50-70% of nocturnal flows. Mean E(n) was 6-8% of the 24-h flux across seasons (spring, summer and winter), but was up to 19% of the 24-h flux on some days in both species. Despite different daytime strategies in water use of the two species, both species demonstrated low night-time water loss, suggesting similar controls on water loss at night. In order to account for the impact of E(n) on pre-dawn leaf water potential arising from the influence of disequilibria between root zone and leaf water potential, we also developed a simple model to more accurately predict soil water potential (ψ(s)).

  11. How do leaf veins influence the worldwide leaf economic spectrum? Review and synthesis.

    Science.gov (United States)

    Sack, Lawren; Scoffoni, Christine; John, Grace P; Poorter, Hendrik; Mason, Chase M; Mendez-Alonzo, Rodrigo; Donovan, Lisa A

    2013-10-01

    Leaf vein traits are implicated in the determination of gas exchange rates and plant performance. These traits are increasingly considered as causal factors affecting the 'leaf economic spectrum' (LES), which includes the light-saturated rate of photosynthesis, dark respiration, foliar nitrogen concentration, leaf dry mass per area (LMA) and leaf longevity. This article reviews the support for two contrasting hypotheses regarding a key vein trait, vein length per unit leaf area (VLA). Recently, Blonder et al. (2011, 2013) proposed that vein traits, including VLA, can be described as the 'origin' of the LES by structurally determining LMA and leaf thickness, and thereby vein traits would predict LES traits according to specific equations. Careful re-examination of leaf anatomy, published datasets, and a newly compiled global database for diverse species did not support the 'vein origin' hypothesis, and moreover showed that the apparent power of those equations to predict LES traits arose from circularity. This review provides a 'flux trait network' hypothesis for the effects of vein traits on the LES and on plant performance, based on a synthesis of the previous literature. According to this hypothesis, VLA, while virtually independent of LMA, strongly influences hydraulic conductance, and thus stomatal conductance and photosynthetic rate. We also review (i) the specific physiological roles of VLA; (ii) the role of leaf major veins in influencing LES traits; and (iii) the role of VLA in determining photosynthetic rate per leaf dry mass and plant relative growth rate. A clear understanding of leaf vein traits provides a new perspective on plant function independently of the LES and can enhance the ability to explain and predict whole plant performance under dynamic conditions, with applications towards breeding improved crop varieties.

  12. 75 FR 14607 - Small Entity Compliance Guide: Bottled Water: Total Coliform and E. coli

    Science.gov (United States)

    2010-03-26

    ...] Small Entity Compliance Guide: Bottled Water: Total Coliform and E. coli; Availability AGENCY: Food and... the availability of a guidance for industry entitled ``Bottled Water: Total Coliform and E. coli... determine whether any of the coliform organisms are Escherichia coli (E. coli), an indicator of fecal...

  13. Coordination of stem and leaf hydraulic conductance in southern California shrubs: a test of the hydraulic segmentation hypothesis.

    Science.gov (United States)

    Pivovaroff, Alexandria L; Sack, Lawren; Santiago, Louis S

    2014-08-01

    Coordination of water movement among plant organs is important for understanding plant water use strategies. The hydraulic segmentation hypothesis (HSH) proposes that hydraulic conductance in shorter lived, 'expendable' organs such as leaves and longer lived, more 'expensive' organs such as stems may be decoupled, with resistance in leaves acting as a bottleneck or 'safety valve'. We tested the HSH in woody species from a Mediterranean-type ecosystem by measuring leaf hydraulic conductance (Kleaf) and stem hydraulic conductivity (KS). We also investigated whether leaves function as safety valves by relating Kleaf and the hydraulic safety margin (stem water potential minus the water potential at which 50% of conductivity is lost (Ψstem-Ψ50)). We also examined related plant traits including the operating range of water potentials, wood density, leaf mass per area, and leaf area to sapwood area ratio to provide insight into whole-plant water use strategies. For hydrated shoots, Kleaf was negatively correlated with KS , supporting the HSH. Additionally, Kleaf was positively correlated with the hydraulic safety margin and negatively correlated with the leaf area to sapwood area ratio. Consistent with the HSH, our data indicate that leaves may act as control valves for species with high KS , or a low safety margin. This critical role of leaves appears to contribute importantly to plant ecological specialization in a drought-prone environment. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  14. Height is more important than light in determining leaf morphology in a tropical forest.

    Science.gov (United States)

    Cavaleri, Molly A; Oberbauer, Steven F; Clark, David B; Clark, Deborah A; Ryan, Michael G

    2010-06-01

    Both within and between species, leaf physiological parameters are strongly related to leaf dry mass per area (LMA, g/m2), which has been found to increase from forest floor to canopy top in every forest where it has been measured. Although vertical LMA gradients in forests have historically been attributed to a direct phenotypic response to light, an increasing number of recent studies have provided evidence that water limitation in the upper canopy can constrain foliar morphological adaptations to higher light levels. We measured height, light, and LMA of all species encountered along 45 vertical canopy transects across a Costa Rican tropical rain forest. LMA was correlated with light levels in the lower canopy until approximately 18 m sample height and 22% diffuse transmittance. Height showed a remarkably linear relationship with LMA throughout the entire vertical canopy profile for all species pooled and for each functional group individually (except epiphytes), possibly through the influence of gravity on leaf water potential and turgor pressure. Models of forest function may be greatly simplified by estimating LMA-correlated leaf physiological parameters solely from foliage height profiles, which in turn can be assessed with satellite- and aircraft-based remote sensing.

  15. Seasonal changes in total body water; body composition and water turnover in reindeer

    Directory of Open Access Journals (Sweden)

    Terje S. Larsen

    1985-05-01

    Full Text Available Total body water and water turnover were measured at different times throughout the year in 3 captive Norwegian reindeer, using a tritiated water dilution method (Holleman et al. 1982. Total body water (percent of body weight increased during late autumn and winter, from 59.1 ± 1.5 % in October to 72.5 ± 2.0 % in April. Using the equatation by Pace and Rathbun (1945 for predicting total body fat (% fat = 100 - % water/0.732, this increase in total body water indicates a concomitant reduction in body fat, from a maximum value of 18.9 ± 2.6 % (of body weight in October to a minimum of 0.9 ± 2.7 % in April. During summer, on the other hand, fat content increased at the expense of a reduced percentage of body water. Water turnover was low in winter (December - April, ranging between 30.8 ± 5.2and43.6 ± 13.5ml.d-'. kg-1, but increased nearly fourfold during summer (June-August with a maximum of 117.7 ± 5.9 ml.d-1. kg-1 in August. Positive correlations between water turnover and food intake and between water turnover and ambient temperature were found, the latter probably resulting from an incidental correlation between food intake and ambient temperature.Sesongmessige forandringer i totalt kroppsvann, kropps-sammensetning og vannomsetning hos reinsdyr.Abstract in Norwegian / Sammendrag: Totalt kroppsvann og vannomsetning av vann ble målt til forskjellige årstider i 3 norske reinsdyr ved hjelp av utvasking av tritiert vann (Holleman et al. 1982. Totalt kroppsvann (prosent av kroppsvekt økte utover høsten og vinteren, fra 59.1 ± 1.5 % i oktober til 72.5 ± 2.0 % i april. Ved hjelp av en ligning som er gitt av Pace og Rathbun (1945 for beregning av totalt kroppsfett (% fett = 100 - % vann/0.732, fant en at denne økningen i vanninnhold tilsvarte en samtidig reduksjon i fettinnhold, fra en maksimums-verdi på 18.9 ± 2.6 % av kroppsvekt i oktober til et minimum på 0.9 ± 2.7 % i april. Utover sommeren økte derimot innholdet av fett p

  16. Organic compounds leached from fast pyrolysis mallee leaf and bark biochars.

    Science.gov (United States)

    Lievens, Caroline; Mourant, Daniel; Gunawan, Richard; Hu, Xun; Wang, Yi

    2015-11-01

    Characterization of organic compounds leached from biochars is essential in assessing the possible toxicity of the biochar to the soils' biota. In this study the nature of the leached organic compounds from Mallee biochars, produced from pyrolysis of Mallee leaf and bark in a fluidised-bed pyrolyser at 400 and 580°C was investigated. Light bio-oil compounds and aromatic organic compounds were investigated. The 'bio-oil like' light compounds from leaf and bark biochars 'surfaces were obtained after leaching the chars with a solvent, suitable to dissolve the respective bio-oils. GC/MS was implemented to investigate the leachates. Phenolics, which are potentially harmful toxins, were detected and their concentration shown to be dependent on the char's origin and the char production temperature. Further, to simulate biochars amendment to soils, the chars were leached with water. The water-leached aromatic compounds from leaf and bark biochars were characterized using UV-fluorescence spectroscopy. Those results suggested that biochars contain leachable compounds of which the nature and amount is dependent on the biomass feedstock, pyrolysis temperature and leaching time. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Allelopathic effects of leaf and corm water extract of saffron (Crocus sativus L. on germination and seedling growth of flixweed (Descurainia sophia L. and downy brome (Bromus tectorum L.

    Directory of Open Access Journals (Sweden)

    Zeinab Alipoor

    2015-04-01

    Full Text Available This study was conducted in two factorial experiment based on completely randomized design with three replications at research laboratory of faculty of agriculture in University of Birjand in 2013. Factors included saffron organs at 2 levels (leaves and corms and water extract concentrations at 5 levels (0, 0.5, 1, 1.5 and 2 percent.The allelopathic effects of saffron leaves and corms on seed germination and seedling growth characteristics of flixweed (Descurainia sophia L. and downy brome (Bromus tectorum L. were studied in two separate experiments. Results indicated lowest seed germination percentage of downy brome and flixweed were observed at concentration of 2% of corm extract (by 65% and 66% reduce compared to control, respectively. The rate of germination of downy brome decreased (by 71% compared to control with concentration of 2% of leaf extract but the rate of germination on flixweed was not significantly affected by extract concentrations. Different concentrations of leaf and corm extracts significantly decreased length and weight of plumule and radicals of two weeds. A logistic model provided a successful estimation of relationship between leaf water extract and germination percentage of two weeds. Based on orthogonal comparison tests, the allelopathic inhibition effects of saffron leaves and corms were more on downy brome and flixweed, respectively.

  18. Leaf area index drives soil water availability and extreme drought-related mortality under elevated CO2 in a temperate grassland model system.

    Science.gov (United States)

    Manea, Anthony; Leishman, Michelle R

    2014-01-01

    The magnitude and frequency of climatic extremes, such as drought, are predicted to increase under future climate change conditions. However, little is known about how other factors such as CO2 concentration will modify plant community responses to these extreme climatic events, even though such modifications are highly likely. We asked whether the response of grasslands to repeat extreme drought events is modified by elevated CO2, and if so, what are the underlying mechanisms? We grew grassland mesocosms consisting of 10 co-occurring grass species common to the Cumberland Plain Woodland of western Sydney under ambient and elevated CO2 and subjected them to repeated extreme drought treatments. The 10 species included a mix of C3, C4, native and exotic species. We hypothesized that a reduction in the stomatal conductance of the grasses under elevated CO2 would be offset by increases in the leaf area index thus the retention of soil water and the consequent vulnerability of the grasses to extreme drought would not differ between the CO2 treatments. Our results did not support this hypothesis: soil water content was significantly lower in the mesocosms grown under elevated CO2 and extreme drought-related mortality of the grasses was greater. The C4 and native grasses had significantly higher leaf area index under elevated CO2 levels. This offset the reduction in the stomatal conductance of the exotic grasses as well as increased rainfall interception, resulting in reduced soil water content in the elevated CO2 mesocosms. Our results suggest that projected increases in net primary productivity globally of grasslands in a high CO2 world may be limited by reduced soil water availability in the future.

  19. An evolutionary perspective on leaf economics : Phylogenetics of leaf mass per area in vascular plants

    NARCIS (Netherlands)

    Flores, Olivier; Garnier, Eric; Wright, Ian J.; Reich, Peter B.; Pierce, Simon; Diaz, Sandra; Pakeman, Robin J.; Rusch, Graciela M.; Bernard-Verdier, Maud; Testi, Baptiste; Bakker, Jan P.; Bekker, Renee M.; Cerabolini, Bruno E. L.; Ceriani, Roberta M.; Cornu, Guillaume; Cruz, Pablo; Delcamp, Matthieu; Dolezal, Jiri; Eriksson, Ove; Fayolle, Adeline; Freitas, Helena; Golodets, Carly; Gourlet-Fleury, Sylvie; Hodgson, John G.; Brusa, Guido; Kleyer, Michael; Kunzmann, Dieter; Lavorel, Sandra; Papanastasis, Vasilios P.; Perez-Harguindeguy, Natalia; Vendramini, Fernanda; Weiher, Evan

    In plant leaves, resource use follows a trade-off between rapid resource capture and conservative storage. This "worldwide leaf economics spectrum" consists of a suite of intercorrelated leaf traits, among which leaf mass per area, LMA, is one of the most fundamental as it indicates the cost of leaf

  20. The heterogeneity and spatial patterning of structure and physiology across the leaf surface in giant leaves of Alocasia macrorrhiza.

    Directory of Open Access Journals (Sweden)

    Shuai Li

    Full Text Available Leaf physiology determines the carbon acquisition of the whole plant, but there can be considerable variation in physiology and carbon acquisition within individual leaves. Alocasia macrorrhiza (L. Schott is an herbaceous species that can develop very large leaves of up to 1 m in length. However, little is known about the hydraulic and photosynthetic design of such giant leaves. Based on previous studies of smaller leaves, and on the greater surface area for trait variation in large leaves, we hypothesized that A. macrorrhiza leaves would exhibit significant heterogeneity in structure and function. We found evidence of reduced hydraulic supply and demand in the outer leaf regions; leaf mass per area, chlorophyll concentration, and guard cell length decreased, as did stomatal conductance, net photosynthetic rate and quantum efficiency of photosystem II. This heterogeneity in physiology was opposite to that expected from a thinner boundary layer at the leaf edge, which would have led to greater rates of gas exchange. Leaf temperature was 8.8°C higher in the outer than in the central region in the afternoon, consistent with reduced stomatal conductance and transpiration caused by a hydraulic limitation to the outer lamina. The reduced stomatal conductance in the outer regions would explain the observed homogeneous distribution of leaf water potential across the leaf surface. These findings indicate substantial heterogeneity in gas exchange across the leaf surface in large leaves, greater than that reported for smaller-leafed species, though the observed structural differences across the lamina were within the range reported for smaller-leafed species. Future work will determine whether the challenge of transporting water to the outer regions can limit leaf size for plants experiencing drought, and whether the heterogeneity of function across the leaf surface represents a particular disadvantage for large simple leaves that might explain their

  1. Procedures for extraction and purification of leaf wax biomarkers from peats

    Directory of Open Access Journals (Sweden)

    J.E. Nichols

    2011-12-01

    Full Text Available Palaeoecological and palaeoclimate reconstruction, using leaf wax biomarkers, is a relatively new sub-discipline of peatland science. The ability to process large numbers of samples rapidly for biomarkers makes this type of analysis particularly appealing. This review is a guide to the preparation of leaf waxes for analysis by gas chromatography. The main phases of preparation are extraction of soluble organic compounds from sediment, separation of the total extract into fractions of differing polarity, and the derivatisation of polar functional groups. The procedures described here are not meant be exhaustive of all organic geochemical possibilities in peatlands, but a distillation of methods for the preparation of leaf waxes that are commonly and increasingly being used in palaeoecological and palaeoclimatological studies.

  2. [Total drinking water intake and sources of children and adolescent in one district of Shenzhen].

    Science.gov (United States)

    Du, Songming; Hu, Xiaoqi; Zhang, Qian; Wang, Xiaojun; Liu, Ailing; Pan, Hui; He, Shuang; Ma, Guansheng

    2013-05-01

    To describe total drinking water intake among primary and middle school students in one district of Shenzhen and to provide scientific evidence for adequate intakes of drinking water for different people in China. A total of 816 students from three primary and middle schools of Shenzhen was selected using three-stage random sampling method. The information on amounts and types of daily drinking water was recorded by subjects for seven consecutive days using a 24 hours measurement. The amounts and types of daily drinking water among different ages and between boys and girls were analyzed. The average total drinking water of subjects was (1225+/-557) ml/d, and the consumption of total drinking water in boys ((1303+/-639) ml/d) was significantly higher than that in girls ((1134+/-478) ml/d, Pwater of secondary school students ((1389+/-541) ml/d) and high school student ((1318+/-641) ml/d) was no statistically difference, but was higher than primary school students ((1097+/-525) ml/d, Pwater and beverages of the subjects was (818+/-541) ml/d and (407+/-294) ml/d respectively. Major of fluid intake comes from drinking water in children and adolescenct of Shenzhen. The knowledge of drinking water of primary school students is need to comprehensive enough.

  3. Response of leaf and whole-tree canopy conductance to wet conditions within a mature premontane tropical forest in Costa Rica

    Science.gov (United States)

    Aparecido, L. M. T.; Miller, G. R.; Cahill, A. T.; Andrews, R.; Moore, G. W.

    2017-12-01

    Tropical water recycling and carbon storage are dependent on canopy-atmosphere dynamics, which are substantially altered when rainfall occurs. However, models only indirectly consider leaf wetness as a driving factor for carbon and water fluxes. To better understand how leaf wetness condition affects stomatal and canopy conductance to water vapor, we tested a set of widely used models for a mature tropical forest of Costa Rica with prolonged periods of wet leaves. We relied on a year of sap flux measurements from 26 trees to estimate transpiration (Ec) and multiple micrometeorological profile measurements from a 40-m tower to be used in the models. Stomatal conductance (gs) models included those proposed by Jones (1992) (gs-J), using shaded and sunlit leaf temperatures, and Monteith and Unsworth (1990) (gs-MU), using air temperature. Canopy conductance (gc) models included those proposed by McNaughton and Jarvis (1983) (gc-MJ) and Penman-Monteith (gc-PM). Between gs and gc, gc had the largest differences within models during dry periods; while estimates were most similar during wet periods. Yet, all gc and gs estimates on wet days were at least as high as on dry days, indicative of their insensitivity to leaf wetness. Shaded leaf gs averaged 26% higher than in sunlit leaves. Additionally, the highly decoupled interface (Ω>0.90) reflected multiple environmental drivers that may influence conductance (e.g. vapor pressure deficit and leaf temperature). This was also seen through large shifts of diurnal peaks of gs and gc (up to 2 hours earlier than Ec) associated with the daily variation of air temperature and net radiation. Overall, this study led to three major insights: 1) gc and gs cannot accurately be predicted under wet conditions without accounting for leaf wetness, 2) even during dry days, low vapor pressure deficits interfere with model accuracy, and 3) intermittent rain during semi-dry and wet days cause large fluctuations in gc and gs estimates. Thus, it

  4. Hypolipidemic Effect of Psidium guajava Leaf Extract Against Hepatotoxicity in Rats.

    Science.gov (United States)

    Vijayakumar, K; Rengarajan, R L; Radhakrishnan, R; Anand, A Vijaya

    2018-01-01

    Plant-based natural extracts cure several diseases in human. However, the extract of Psidium guajava leaf is not yet evaluated on changes of lipid profile in hepatic disease affected rats. The present study was aimed to evaluate the mitigation effect of the ethanolic extract of P. guajava leaf and its isolated quercetin fraction on hepatotoxic rats. Carbon tetrachloride (CCl 4 ) was injected to rats for hepatic disease induction and silymarin drug was used as positive control to compare plant ethanolic extract. The lipid profiles were assessed in both plasma and liver tissue of diseased and control rats. Levels of total cholesterol, triglycerides, free fatty acids, phospholipids, and low-density lipoprotein cholesterol were increased and the level of high-density lipoprotein cholesterol (HDL-C) was decreased in CCl 4 -induced hepatotoxic rats. The treatment of P. guajava (100, 200, and 300 mg/kg, bw) and isolated quercetin fraction (20 mg/kg, bw) doses decreased the elevated levels of all these parameters in diseased rats and restored the normal concentration of HDL-C. The results of the present study concluded that the P. guajava leaf and its isolated quercetin fraction can significantly regulate lipid metabolism in CCl 4 -induced hepatotoxic rats and decrease the disease rate. Psidium guajava leaf extract reduces the hepatotoxicity and disease rate in ratsQuercetin fraction of leaf extract significantly regulates lipid profile in hepatic diseased rats. Abbreviations used: CCl 4 : Carbon tetrachloride; FFA: Free fatty acids; HDL-C: High-density lipoprotein cholesterol; LCAT: Lecithin cholesterol acyltransferase; LDL-C: Low-density lipoprotein cholesterol; PL: Phospholipids; TC: Total cholesterol; TG: Triglycerides; VLDL-C: Very low-density lipoprotein cholesterol.

  5. Easy Leaf Area: Automated digital image analysis for rapid and accurate measurement of leaf area.

    Science.gov (United States)

    Easlon, Hsien Ming; Bloom, Arnold J

    2014-07-01

    Measurement of leaf areas from digital photographs has traditionally required significant user input unless backgrounds are carefully masked. Easy Leaf Area was developed to batch process hundreds of Arabidopsis rosette images in minutes, removing background artifacts and saving results to a spreadsheet-ready CSV file. • Easy Leaf Area uses the color ratios of each pixel to distinguish leaves and calibration areas from their background and compares leaf pixel counts to a red calibration area to eliminate the need for camera distance calculations or manual ruler scale measurement that other software methods typically require. Leaf areas estimated by this software from images taken with a camera phone were more accurate than ImageJ estimates from flatbed scanner images. • Easy Leaf Area provides an easy-to-use method for rapid measurement of leaf area and nondestructive estimation of canopy area from digital images.

  6. Impairment of leaf photosynthesis after insect herbivory or mechanical injury on common milkweed, Asclepias syriaca.

    Science.gov (United States)

    Delaney, K J; Haile, F J; Peterson, R K D; Higley, L G

    2008-10-01

    Insect herbivory has variable consequences on plant physiology, growth, and reproduction. In some plants, herbivory reduces photosynthetic rate (Pn) activity on remaining tissue of injured leaves. We sought to better understand the influence of leaf injury on Pn of common milkweed, Asclepias syriaca (Asclepiadaceae), leaves. Initially, we tested whether Pn reductions occurred after insect herbivory or mechanical injury. We also (1) examined the duration of photosynthetic recovery, (2) compared mechanical injury with insect herbivory, (3) studied the relationship between leaf Pn with leaf injury intensity, and (4) considered uninjured leaf compensatory Pn responses neighboring an injured leaf. Leaf Pn was significantly reduced on mechanically injured or insect-fed leaves in all reported experiments except one, so some factor(s) (cardiac glycoside induction, reproductive investment, and water stress) likely interacts with leaf injury to influence whether Pn impairment occurs. Milkweed tussock moth larval herbivory, Euchaetes egle L. (Arctiidae), impaired leaf Pn more severely than mechanical injury in one experiment. Duration of Pn impairment lasted > 5 d to indicate high leaf Pn sensitivity to injury, but Pn recovery occurred within 13 d in one experiment. The degree of Pn reduction was more severe from E. egle herbivory than similar levels of mechanical tissue removal. Negative linear relationships characterized leaf Pn with percentage tissue loss from single E. egle-fed leaves and mechanically injured leaves and suggested that the signal to trigger leaf Pn impairment on remaining tissue of an injured leaf was amplified by additional tissue loss. Finally, neighboring uninjured leaves to an E. egle-fed leaf had a small (approximately 10%) degree of compensatory Pn to partly offset tissue loss and injured leaf Pn impairment.

  7. Response of range grasses to water produced from in situ fossil fuel processing

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, Q D; Moore, T S; Sexton, J C

    1984-11-01

    In situ-produced waters collected while retorting oil shale and tar sands to produce oil, and coal to produce gas, were tested for their effects on plant growth. Basin wildrye (Elymus cinereus), western wheatgrass (Agropyron smithii) 'Rosana', alkali sacaton (Sporobolus airoides), bluebunch wheatgrass (Agropyron spicatum) and Nuttall alkaligrass (Puccinellia airoides) were utilized. Root weight, shoot weight, total dry weight, leaf area and root/shoot weight ratios were determined. All experiments were conducted under greenhouse conditions using hydroponic techniques and horticultural grade perlite for plant support. Measurements were collected after a 10-week growth period. Results show that differences in plant growth can be monitored using dry biomass, leaf area and root to shoot ratio measurements when plants are subjected to retort waters. Plant species reaction to a water may be different. Generally, alkali sacaton, basin wildrye and western wheatgrass are least susceptible to toxicity by the majority of retort waters tested. Bluebunch wheatgrass is most susceptible. Waters from different retort procedures vary in toxicity to different plant species.

  8. An inexpensive optical sensor system for monitoring total suspended solids in water

    International Nuclear Information System (INIS)

    Sami Gumaan Daraigan; Mohd Zubir Matjafri; Khiruddin Abdullah; Azlan Abdul Aziz; Abdul Aziz Tajuddin; Mohd Firdaus Othman

    2005-01-01

    The objectives of this work are to design and develop an optical transsmissometer sensor for measuring total suspended solids TSS concentrations in water samples. The proposed optical sensor has the advantages of being relatively inexpensive, and easy to make and operate. An optical algorithm has been developed and used for the measurement of total suspended solids concentrations. The developed optical sensor components include light emitting diodes LEDs that are used for measuring transmitted light. The concentrations of total suspended solids TSS are determined from transmitted light through the water samples. The transmitted light is measured in terms of the output voltage of the photodetector of the sensor system. The readings are measured using a digital multimeter. The results indicate that the level of the photocurrent is linearly proportional to the total suspended solids concentration. The proposed algorithm produces a high correlation coefficient and low root mean square error. (Author)

  9. Occurrence of barley leaf disease and control strategies in Denmark

    DEFF Research Database (Denmark)

    Jørgensen, Lise Nistrup; Ørum, Jens Erik; Heick, Thies Marten

    Barley (Hordeum vulgare) is one of the major crops in Denmark and of special importance for malting and for pig feed. In 2016, the crop was grown covering a total area of 700,000 ha; approximately 25% of arable area in Denmark. To ensure high yield of around 60 dt ha-1, disease-tolerant cultivars...... have proven to be quite effective against all leaf diseases, aside from brown rust and mildew. Denmark has a national record system for pesticide usages. All farmers upload their fungicide use by crop, creating a good basis for assessing the differences in use pattern across different regions...... and fungicide treatments are required. Each year, barley cultivars are assessed for susceptibility towards leaf diseases in national observation plots. The most predominant fungal leaf diseases in Denmark are barley scald (Rhynchosporium secalis), net blotch (Pyrenophora teres), brown rust (Puccinia hordei...

  10. Calibrations between chlorophyll meter values and chlorophyll contents vary as the result of differences in leaf structure

    Science.gov (United States)

    In order to relate leaf chlorophyll meter values with total leaf chlorophyll contents (µg cm-2), calibration equations are established with measured data on leaves. Many studies have documented differences in calibration equations using different species and using different growing conditions for th...

  11. Drought adaptation strategies of four grapevine cultivars (Vitis vinifera L.: modification of the properties of the leaf area

    Directory of Open Access Journals (Sweden)

    María Gómez-del-Campo

    2003-09-01

    Full Text Available This essay studies the morphological and anatomical properties of the leaves of Garnacha tinta, Tempranillo, Chardonnay and Airén grapevines in order to discover the drought adaptation strategies present in Vitis vinifera L. The grapevines were grown under two water availability conditions: water limitation and non-water limitation. There was a significantly lower development of leaf area under conditions of water limitation compared to non-water limitation due to a reduction in the size of main and lateral shoot leaves, and a smaller number of leaves on lateral shoots. The development of the leaf area under water limitation conditions occurred on earlier dates than under non-water limitation conditions. Significantly lower stomatal density was observed under water limitation conditions rather than non-water limitation conditions exclusively in the Airén cultivar.

  12. Smallholder Food and Water Security in the Face of Climatic Stress and the Coffee Leaf Rust: Lessons from Nicaragua

    Science.gov (United States)

    Stewart, I. T.; Bacon, C. M.; Sundstrom, W.

    2015-12-01

    Smallholder farmers in Nicaragua and throughout much of Central America preserve forest biodiversity and contribute to the sustainable production of coffee and other crops while, paradoxically, they themselves must cope with recurring periods of seasonal hunger. Smallholder food and water security in the region is affected by hurricanes, periodic drought events, climatic changes, an on-going outbreak of the coffee leaf rust, and fluctuations in food prices. Using regression analysis, our research examines what factors strengthened resilience to these hazards at the household level over the 1981 - 2014 time period. To this end, we integrate qualitative research on coping responses and local institutions, a participatory survey of 368 households, and an analysis of hydro-climatic data. Our results indicate that coping responses to the coffee leaf rust outbreak and the 2014 drought are comparable in severity to those used to endure Hurricane Mitch in 1998, and a severe 2009 drought. Higher smallholder resilience to stresses affecting food and water security is associated with larger farms, off-farm employment, more on-farm food production, higher numbers of fruit trees, and greater coffee harvests. Households that reported more severe coping responses to hazards earlier in the study period tended to be more strongly impacted by later hazards and reported generally greater seasonal hunger. Affiliation with local farmer-to-farmer institutions prioritizing either subsistence-oriented production or sales to international fair-trade markets did not correlate strongly with coping responses; however, subsistence-oriented institutions promote several resilience-enhancing practices. Lessons learned by adapting to past hazards may be used to develop adaptation and mitigation strategies for smallholders under continued climate variability and change.

  13. Spatial trends in leaf size of Amazonian rainforest trees

    Science.gov (United States)

    Malhado, A. C. M.; Malhi, Y.; Whittaker, R. J.; Ladle, R. J.; Ter Steege, H.; Phillips, O. L.; Butt, N.; Aragão, L. E. O. C.; Quesada, C. A.; Araujo-Murakami, A.; Arroyo, L.; Peacock, J.; Lopez-Gonzalez, G.; Baker, T. R.; Anderson, L. O.; Almeida, S.; Higuchi, N.; Killeen, T. J.; Monteagudo, A.; Neill, D.; Pitman, N.; Prieto, A.; Salomão, R. P.; Vásquez-Martínez, R.; Laurance, W. F.

    2009-08-01

    Leaf size influences many aspects of tree function such as rates of transpiration and photosynthesis and, consequently, often varies in a predictable way in response to environmental gradients. The recent development of pan-Amazonian databases based on permanent botanical plots has now made it possible to assess trends in leaf size across environmental gradients in Amazonia. Previous plot-based studies have shown that the community structure of Amazonian trees breaks down into at least two major ecological gradients corresponding with variations in soil fertility (decreasing from southwest to northeast) and length of the dry season (increasing from northwest to south and east). Here we describe the geographic distribution of leaf size categories based on 121 plots distributed across eight South American countries. We find that the Amazon forest is predominantly populated by tree species and individuals in the mesophyll size class (20.25-182.25 cm2). The geographic distribution of species and individuals with large leaves (>20.25 cm2) is complex but is generally characterized by a higher proportion of such trees in the northwest of the region. Spatially corrected regressions reveal weak correlations between the proportion of large-leaved species and metrics of water availability. We also find a significant negative relationship between leaf size and wood density.

  14. Potential of Chromolaena odorata Leaf as A Cure of Aeromonas hydrophila on Giant Gouramy (Osphronemus gouramy

    Directory of Open Access Journals (Sweden)

    Y. Hadiroseyani

    2007-07-01

    Full Text Available This study was conducted to examine the potency of Chromolaena odorata leaf extract as a medicine for skin eruption disease caused by  Aeromonas hydrophila in giant gouramy Osphronemus gouramy.  Leaf extract of Chromolaena odorata for in vitro test was 0 (as control, 13000, 15000, 17000, 19000 and 21000 ppm, poured onto TSA medium containing bacteria 103 cfu/ml, and then is incubated for 24 hours. In vivo test was performed by injecting bacteria 0.1 ml of 109 cfu/ml intramuscularly into giant gouramy (14 g weight, and then  fish were maintained in the water containing 15000 ppm of Chromolaena odorata leaf extract. In vitro study showed that prevention area of leaf extract against Aeromonas hydrophila was increase by increasing the concentration of leaf extract used, reached 9,33 mm.  Prevention zone of leaf extract by difusion tends to constant, reached 7,6 mm. By in vivo test, survival rate of giant gouramy infected by Aeromonas hydrophila was no significantly different between dosages of leaf extract.  All treated fish, excluded control died after 24 hours infection. Keywords: Aeromonas hydrophila, Osphronemus gouramy, Chromolaena odorata   ABSTRAK Penelitian ini dilakukan untuk mengetahui potensi daun kirinyuh Chromolaena odorata sebagai obat untuk penyakit cacar yang diakibatkan oleh Aeromonas hydrophila pada ikan gurame Osphronemus gouramy. Konsentrasi ekstrak daun Chromolaena odorata untuk uji in vitro adalah 13000, 15000, 17000, 19000 dan 21000 serta 0 ppm sebagai kontrol, yang diletakkan di atas media TSA yang telah mengandung biakan bakteri 103 cfu/ml dan diinkubasi selama 24 jam. Uji in vivo dilakukan dengan menginjeksikan bakteri  sebanyak 0,1 ml (109 cfu/ml secara intramuskular ke ikan gurame (berat 14 g dan kemudian ikan dipelihara dalam air yang mengandung ekstrak daun kirinyuh 15000 ppm. Hasil uji in virto menunjukkan bahwa semakin tinggi konsentrasi ekstrak daun kirinyuh basah semakin efektif dalam menghambat perkembangan

  15. Phytochemical properties and anti-proliferative activity of Olea europaea L. leaf extracts against pancreatic cancer cells.

    Science.gov (United States)

    Goldsmith, Chloe D; Vuong, Quan V; Sadeqzadeh, Elham; Stathopoulos, Costas E; Roach, Paul D; Scarlett, Christopher J

    2015-07-17

    Olea europaea L. leaves are an agricultural waste product with a high concentration of phenolic compounds; especially oleuropein. Oleuropein has been shown to exhibit anti-proliferative activity against a number of cancer types. However, they have not been tested against pancreatic cancer, the fifth leading cause of cancer related death in Western countries. Therefore, water, 50% ethanol and 50% methanol extracts of Corregiola and Frantoio variety Olea europaea L. leaves were investigated for their total phenolic compounds, total flavonoids and oleuropein content, antioxidant capacity and anti-proliferative activity against MiaPaCa-2 pancreatic cancer cells. The extracts only had slight differences in their phytochemical properties, and at 100 and 200 μg/mL, all decreased the viability of the pancreatic cancer cells relative to controls. At 50 μg/mL, the water extract from the Corregiola leaves exhibited the highest anti-proliferative activity with the effect possibly due to early eluting HPLC peaks. For this reason, olive leaf extracts warrant further investigation into their potential anti-pancreatic cancer benefits.

  16. Leaf gas exchange and water status responses of a native and non-native grass to precipitation across contrasting soil surfaces in the Sonoran Desert.

    Science.gov (United States)

    Ignace, Danielle D; Huxman, Travis E; Weltzin, Jake F; Williams, David G

    2007-06-01

    Arid and semi-arid ecosystems of the southwestern US are undergoing changes in vegetation composition and are predicted to experience shifts in climate. To understand implications of these current and predicted changes, we conducted a precipitation manipulation experiment on the Santa Rita Experimental Range in southeastern Arizona. The objectives of our study were to determine how soil surface and seasonal timing of rainfall events mediate the dynamics of leaf-level photosynthesis and plant water status of a native and non-native grass species in response to precipitation pulse events. We followed a simulated precipitation event (pulse) that occurred prior to the onset of the North American monsoon (in June) and at the peak of the monsoon (in August) for 2002 and 2003. We measured responses of pre-dawn water potential, photosynthetic rate, and stomatal conductance of native (Heteropogon contortus) and non-native (Eragrostis lehmanniana) C(4) bunchgrasses on sandy and clay-rich soil surfaces. Soil surface did not always amplify differences in plant response to a pulse event. A June pulse event lead to an increase in plant water status and photosynthesis. Whereas the August pulse did not lead to an increase in plant water status and photosynthesis, due to favorable soil moisture conditions facilitating high plant performance during this period. E. lehmanniana did not demonstrate heightened photosynthetic performance over the native species in response to pulses across both soil surfaces. Overall accumulated leaf-level CO(2) response to a pulse event was dependent on antecedent soil moisture during the August pulse event, but not during the June pulse event. This work highlights the need to understand how desert species respond to pulse events across contrasting soil surfaces in water-limited systems that are predicted to experience changes in climate.

  17. Method validation to determine total alpha beta emitters in water samples using LSC

    International Nuclear Information System (INIS)

    Al-Masri, M. S.; Nashawati, A.; Al-akel, B.; Saaid, S.

    2006-06-01

    In this work a method was validated to determine gross alpha and beta emitters in water samples using liquid scintillation counter. 200 ml of water from each sample were evaporated to 20 ml and 8 ml of them were mixed with 12 ml of the suitable cocktail to be measured by liquid scintillation counter Wallac Winspectral 1414. The lower detection limit by this method (LDL) was 0.33 DPM for total alpha emitters and 1.3 DPM for total beta emitters. and the reproducibility limit was (± 2.32 DPM) and (±1.41 DPM) for total alpha and beta emitters respectively, and the repeatability limit was (±2.19 DPM) and (±1.11 DPM) for total alpha and beta emitters respectively. The method is easy and fast because of the simple preparation steps and the large number of samples that can be measured at the same time. In addition, many real samples and standard samples were analyzed by the method and showed accurate results so it was concluded that the method can be used with various water samples. (author)

  18. Leaf chemical composition of twenty-one Populus hybrid clones grown under intensive culture

    Science.gov (United States)

    Richard E. Dickson; Philip R. Larson

    1976-01-01

    Leaf material from 21 nursery-grown Populus hybrid clones was analyzed for three nitrogen fractions (total N, soluble protein, and soluble amino acids) and three carbhydrate fractions (reducing sugars, total soluble sugars, and total nonstructural carbohydrates-TNC). In addition, nursery-grown green ash and silver maple, field-grown bigtooth and trembling aspen, and...

  19. ACTIVITY OF LEAF-CUTTING ANT Atta sexdens piriventris SUBMITED TO HIGH DILUTION HOMEOPATHIC PREPARATIONS

    Directory of Open Access Journals (Sweden)

    Alexandre Giesel

    2013-02-01

    Full Text Available The effect of high dilution preparations on the movement and foraging activities of Atta sexdens piriventris was evaluated. Five colonies of ants were located on each of the five experimental areas using a randomized complete block design. Three main forage trails from each colony were selected from where evaluations were made. Ten mL of high dilution preparation of Atta sexdens piriventris nosodes and Belladonna homeopathy solution were sprayed over 0.5 m of each selected trail, 1.0 m far from the nest. The controls were pure water and non treated trails. Applications were made daily during 10 days. The total number of ants moving on each trail one meter away from the nest, carrying or not plant fragments, were assessed before the daily application. Dilution preparations at 30CH (thirtieth centesimal Hahnemannian dilution of A. sexdens piriventris nosodes and Belladonna reduced the activities of ants from the fifth day after the first application. The treatment effect lasted more than 20 days after the last application. The use of preparation at 30CH dilution order to reduce the foraging activity of leaf-cutting ants is a potential non residual method to manage leaf-cutting ants.

  20. Leaf endophyte load influences fungal garden development in leaf-cutting ants

    Directory of Open Access Journals (Sweden)

    Van Bael Sunshine A

    2012-11-01

    Full Text Available Abstract Background Previous work has shown that leaf-cutting ants prefer to cut leaf material with relatively low fungal endophyte content. This preference suggests that fungal endophytes exact a cost on the ants or on the development of their colonies. We hypothesized that endophytes may play a role in their host plants’ defense against leaf-cutting ants. To measure the long-term cost to the ant colony of fungal endophytes in their forage material, we conducted a 20-week laboratory experiment to measure fungal garden development for colonies that foraged on leaves with low or high endophyte content. Results Colony mass and the fungal garden dry mass did not differ significantly between the low and high endophyte feeding treatments. There was, however, a marginally significant trend toward greater mass of fungal garden per ant worker in the low relative to the high endophyte treatment. This trend was driven by differences in the fungal garden mass per worker from the earliest samples, when leaf-cutting ants had been foraging on low or high endophyte leaf material for only 2 weeks. At two weeks of foraging, the mean fungal garden mass per worker was 77% greater for colonies foraging on leaves with low relative to high endophyte loads. Conclusions Our data suggest that the cost of endophyte presence in ant forage material may be greatest to fungal colony development in its earliest stages, when there are few workers available to forage and to clean leaf material. This coincides with a period of high mortality for incipient colonies in the field. We discuss how the endophyte-leaf-cutter ant interaction may parallel constitutive defenses in plants, whereby endophytes reduce the rate of colony development when its risk of mortality is greatest.

  1. Phenotypic Plasticity of Leaf Shape along a Temperature Gradient in Acer rubrum

    Science.gov (United States)

    Royer, Dana L.; Meyerson, Laura A.; Robertson, Kevin M.; Adams, Jonathan M.

    2009-01-01

    Both phenotypic plasticity and genetic determination can be important for understanding how plants respond to environmental change. However, little is known about the plastic response of leaf teeth and leaf dissection to temperature. This gap is critical because these leaf traits are commonly used to reconstruct paleoclimate from fossils, and such studies tacitly assume that traits measured from fossils reflect the environment at the time of their deposition, even during periods of rapid climate change. We measured leaf size and shape in Acer rubrum derived from four seed sources with a broad temperature range and grown for two years in two gardens with contrasting climates (Rhode Island and Florida). Leaves in the Rhode Island garden have more teeth and are more highly dissected than leaves in Florida from the same seed source. Plasticity in these variables accounts for at least 6–19 % of the total variance, while genetic differences among ecotypes probably account for at most 69–87 %. This study highlights the role of phenotypic plasticity in leaf-climate relationships. We suggest that variables related to tooth count and leaf dissection in A. rubrum can respond quickly to climate change, which increases confidence in paleoclimate methods that use these variables. PMID:19893620

  2. [Foliar water use efficiency of Platycladus orientalis sapling under different soil water contents].

    Science.gov (United States)

    Zhang, Yong E; Yu, Xin Xiao; Chen, Li Hua; Jia, Guo Dong; Zhao, Na; Li, Han Zhi; Chang, Xiao Min

    2017-07-18

    The determination of plant foliar water use efficiency will be of great value to improve our understanding about mechanism of plant water consumption and provide important basis of regional forest ecosystem management and maintenance, thus, laboratory controlled experiments were carried out to obtain Platycladus orientalis sapling foliar water use efficiency under five different soil water contents, including instantaneous water use efficiency (WUE gs ) derived from gas exchange and short-term water use efficiency (WUE cp ) caculated using carbon isotope model. The results showed that, controlled by stomatal conductance (g s ), foliar net photosynthesis rate (P n ) and transpiration rate (T r ) increased as soil water content increased, which both reached maximum va-lues at soil water content of 70%-80% field capacity (FC), while WUE gs reached a maximum of 7.26 mmol·m -2 ·s -1 at the lowest soil water content (35%-45% FC). Both δ 13 C of water-soluble leaf and twig phloem material achieved maximum values at the lowest soil water content (35%-45% FC). Besides, δ 13 C values of leaf water-soluble compounds were significantly greater than that of phloem exudates, indicating that there was depletion in 13 C in twig phloem compared with leaf water-soluble compounds and no obvious fractionation in the process of water-soluble material transportation from leaf to twig. Foliar WUE cp also reached a maximum of 7.26 mmol·m -2 ·s -1 at the lowest soil water content (35%-45% FC). There was some difference between foliar WUE gs and WUE cp under the same condition, and the average difference was 0.52 mmol·m -2 ·s -1 . The WUE gs had great space-time variability, by contrast, WUE cp was more representative. It was concluded that P. orientalis sapling adapted to drought condition by increasing water use efficiency and decreasing physiological activity.

  3. 40 CFR 130.7 - Total maximum daily loads (TMDL) and individual water quality-based effluent limitations.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 21 2010-07-01 2010-07-01 false Total maximum daily loads (TMDL) and individual water quality-based effluent limitations. 130.7 Section 130.7 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS WATER QUALITY PLANNING AND MANAGEMENT § 130.7 Total...

  4. Easy Leaf Area: Automated Digital Image Analysis for Rapid and Accurate Measurement of Leaf Area

    Directory of Open Access Journals (Sweden)

    Hsien Ming Easlon

    2014-07-01

    Full Text Available Premise of the study: Measurement of leaf areas from digital photographs has traditionally required significant user input unless backgrounds are carefully masked. Easy Leaf Area was developed to batch process hundreds of Arabidopsis rosette images in minutes, removing background artifacts and saving results to a spreadsheet-ready CSV file. Methods and Results: Easy Leaf Area uses the color ratios of each pixel to distinguish leaves and calibration areas from their background and compares leaf pixel counts to a red calibration area to eliminate the need for camera distance calculations or manual ruler scale measurement that other software methods typically require. Leaf areas estimated by this software from images taken with a camera phone were more accurate than ImageJ estimates from flatbed scanner images. Conclusions: Easy Leaf Area provides an easy-to-use method for rapid measurement of leaf area and nondestructive estimation of canopy area from digital images.

  5. Effect of Packaging Materials on Orthosiphon Stamineus Dried-Leaf Quality During Storage

    Science.gov (United States)

    Norawanis, A. R.; Shaari, A. R.; Leng, L. Y.

    2018-03-01

    The experiment was conducted to determine the effects on the total phenolic content, antioxidant capacity, moisture content and total different color (ΔE) when the O. stamineus dried whole-leaf were packed in different packaging materials (plastic bag, paper bag and glass container) and stored under room temperature (±25 °C) and relative humidity (±65 %RH) for 8 weeks. The total phenolic compounds and antioxidant activity were measured using the Folin-Ciocalteu method and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity assay respectively, and analyzed using UV/VIS Spectrophotometer. The moisture content changes were examined using a moisture analyzer and the color changes were analyzed using colorimeter. The results showed that packing O. stamineus dried whole-leaf in different packaging materials significantly affected the herbal leaves quality. After 8 weeks of storage period, the total phenolic content and antioxidant capacity exhibited the increase values during storage. Meanwhile, the moisture content of the samples decreased by storage period for the samples packed in plastic bag and glass container. The moisture content of the samples packed in the paper bag fluctuated along the 8 weeks of storage period. The total different color (ΔE) of the O. stamineus dried whole-leaf increased by storage period. The highest changes of ΔE belonged to the samples packed in the glass container, followed by paper and plastic bags. The selection of the packaging materials can be considered as an important element to control the quality of raw herbal materials for further processing and the herbal finished products.

  6. Soil water availability and rooting depth as determinants of hydraulic architecture of Patagonian woody species

    Science.gov (United States)

    Sandra J. Bucci; Fabian G. Scholz; Guillermo Goldstein; Frederick C. Meinzer; Maria E. Arce

    2009-01-01

    We studied the water economy of nine woody species differing in rooting depth in a Patagonian shrub steppe from southern Argentina to understand how soil water availability and rooting depth determine their hydraulic architecture. Soil water content and potentials, leaf water potentials (Leaf) hydraulic conductivity, wood density (Pw), rooting depth, and specific leaf...

  7. High purity heavy water production: need for total organic carbon determination in process water streams

    International Nuclear Information System (INIS)

    Ayushi; Kumar, Sangita D.; Reddy, A.V.R.; Vithal, G.K.

    2009-01-01

    In recent times, demand for high purity heavy water (99.98% pure) in industries and laboratories has grown by manifold. Its application started in nuclear industry with the design of CANDU reactor, which uses natural uranium as fuel. In this reactor the purest grade of heavy water is used as the moderator and the primary coolant. Diverse industrial applications like fibre optics, medicine, semiconductors etc. use high purity heavy water extensively to achieve better performance of the specific material. In all these applications there is a stringent requirement that the total organic carbon content (TOC) of high purity heavy water should be very low. This is because the presence of TOC can lead to adverse interactions in different applications. To minimize the TOC content in the final product there is a need to monitor and control the TOC content at each and every stage of heavy water production. Hence a simple, rapid and accurate method was developed for the determination of TOC content in process water samples. The paper summarizes the results obtained for the TOC content in the water samples collected from process streams of heavy water production plant. (author)

  8. ACTIVITY TEST OF GUAVA (Psidium guajava L. LEAF METHANOL EXTRACT AS CONTRACEPTION ANTIFERTILITY TO WHITE MICE (Rattus norvegicus

    Directory of Open Access Journals (Sweden)

    Sri Retno Dwi Ariani

    2010-06-01

    Full Text Available The aim of this research is to know about if the guava (Psidium guajava L. leaf methanol extract on 10.5 mg/mL and 21.0 mg/mL dossages indicate a positive test as contraception antifertility to white mice (Rattus norvegicus. The sample is guava leaf from Mungkid, Magelang Central of Java Indonesia. The animals experiment are the white mice on 140-300 g for female, 200-250 g for male and about 3 months of age in average. The steps of this research are : (1 preparing  sample, i.e. washing, drying on to indirect sunlight and make the sample into powder, (2 isolation the guava leaf powder in soxhlet instrument with hexane, (3 evaporation the sample with rotary evaporator until guava leaf hexane extract produced, (4 maseration the sample with methanol, (5 evaporation the sample with rotary evaporator until guava leaf methanol extract produced, (6 conducting contraception antifertility activity test to guave leaf methanol extract on 10.5 mg/mL and 21.0 mg/mL dossages to mice white. The results of this research are guava leaf methanol extract on 10.5 mg/mL and 21.0 mg/mL dossages indicate a negative contraception antifertility test to white mice but in these dossages have indicated that an antiimplantation effect (the total natality of fetus is less than the total implantation site in mice white.   Keywords: Guava leaf, contraseption antifertility, methanol extract, white mice, implantation

  9. Geoecohydrological mechanisms couple soil and leaf water dynamics and facilitate species coexistence in shallow soils of a tropical semiarid mixed forest.

    Science.gov (United States)

    Rodríguez-Robles, Ulises; Arredondo, J Tulio; Huber-Sannwald, Elisabeth; Vargas, Rodrigo

    2015-07-01

    Trees growing on shallow rocky soils must have exceptional adaptations when underlying weathered bedrock has no deep fractures for water storage. Under semiarid conditions, hydrology of shallow soils is expected to decouple from plant hydrology, as soils dry out as a result of rapid evaporation and competition for water increases between coexisting tree species. Gas exchange and plant-water relations were monitored for 15 months for Pinus cembroides and Quercus potosina tree species in a tropical semiarid forest growing on c. 20-cm-deep soils over impermeable volcanic bedrock. Soil and leaf water potential maintained a relatively constant offset throughout the year in spite of high intra-annual fluctuations reaching up to 5 MPa. Thus, hydrology of shallow soils did not decouple from hydrology of trees even in the driest period. A combination of redistribution mechanisms of water stored in weathered bedrock and hypodermic flow accessible to oak provided the source of water supply to shallow soils, where most of the actively growing roots occurred. This study demonstrates a unique geoecohydrological mechanism that maintains a tightly coupled hydrology between shallow rocky soils and trees, as well as species coexistence in this mixed forest, where oak facilitates water access to pine. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  10. Experimental manipulation of leaf litter colonization by aquatic invertebrates in a third order tropical stream.

    Science.gov (United States)

    Uieda, V S; Carvalho, E M

    2015-05-01

    Through a manipulative experiment, the colonization of leaf litter by invertebrates was investigated in two sections of a tropical stream (spatial scale) that differed in function of the canopy cover, one with the presence (closed area) and another without riparian vegetation (open area), during one month of the dry and one of the wet season (temporal scale). The work aimed to verify differences related to four variables: season, canopy cover, leaf type and leaf condition. Litter bags containing arboreal and herbaceous leaves (leaf type variable), non-conditioned and preconditioned (leaf condition variable) were placed at the bottom of the stream in each area (canopy cover variable) and season (dry and wet), and removed after 13-day colonization. The analysis of the remaining litter dry mass per leaf bag emphasizes differences related mainly to seasonality, canopy cover and leaf type, although leaf condition was also important when combined with those three factors. Comparing the abundance of invertebrates per treatment, there was a tendency of high predominance of Chironomidae during the dry season and greater taxa diversity and evenness during the wet season, when the water flow increase could alter the availability of microhabitats for local fauna. Even though canopy cover alone was not a significant source of variation in the abundance of invertebrates, the results showed a tendency of a combined effect of canopy cover with seasonality and leaf condition.

  11. Automated Leaf Tracking using Multi-view Image Sequences of Maize Plants for Leaf-growth Monitoring

    Science.gov (United States)

    Das Choudhury, S.; Awada, T.; Samal, A.; Stoerger, V.; Bashyam, S.

    2017-12-01

    Extraction of phenotypes with botanical importance by analyzing plant image sequences has the desirable advantages of non-destructive temporal phenotypic measurements of a large number of plants with little or no manual intervention in a relatively short period of time. The health of a plant is best interpreted by the emergence timing and temporal growth of individual leaves. For automated leaf growth monitoring, it is essential to track each leaf throughout the life cycle of the plant. Plants are constantly changing organisms with increasing complexity in architecture due to variations in self-occlusions and phyllotaxy, i.e., arrangements of leaves around the stem. The leaf cross-overs pose challenges to accurately track each leaf using single view image sequence. Thus, we introduce a novel automated leaf tracking algorithm using a graph theoretic approach by multi-view image sequence analysis based on the determination of leaf-tips and leaf-junctions in the 3D space. The basis of the leaf tracking algorithm is: the leaves emerge using bottom-up approach in the case of a maize plant, and the direction of leaf emergence strictly alternates in terms of direction. The algorithm involves labeling of the individual parts of a plant, i.e., leaves and stem, following graphical representation of the plant skeleton, i.e., one-pixel wide connected line obtained from the binary image. The length of the leaf is measured by the number of pixels in the leaf skeleton. To evaluate the performance of the algorithm, a benchmark dataset is indispensable. Thus, we publicly release University of Nebraska-Lincoln Component Plant Phenotyping dataset-2 (UNL-CPPD-2) consisting of images of the 20 maize plants captured by visible light camera of the Lemnatec Scanalyzer 3D high throughout plant phenotyping facility once daily for 60 days from 10 different views. The dataset is aimed to facilitate the development and evaluation of leaf tracking algorithms and their uniform comparisons.

  12. Water cut measurement of oil–water flow in vertical well by combining total flow rate and the response of a conductance probe

    International Nuclear Information System (INIS)

    Chen, Jianjun; Xu, Lijun; Cao, Zhang; Zhang, Wen; Liu, Xingbin; Hu, Jinhai

    2015-01-01

    In this paper, a conductance probe-based well logging instrument was developed and the total flow rate is combined with the response of the conductance probe to estimate the water cut of the oil–water flow in a vertical well. The conductance probe records the time-varying electrical characteristics of the oil–water flow. Linear least squares regression (LSR) and nonlinear support vector regression (SVR) were used to establish models to map the total flow rate and features extracted from the probe response onto the water cut, respectively. Principal component analysis (PCA) and partial least squares analysis (PLSA) techniques were employed to reduce data redundancy within the extracted features. An experiment was carried out in a vertical pipe with an inner diameter of 125 mm and a height of 24 m in an experimental multi-phase flow setup, Daqing Oilfield, China. In the experiment, oil–water flow was used and the total flow rate varied from 10 to 200 m 3 per day and the water cut varied from 0% to 100%. As a direct comparison, the cases were also studied when the total flow rate was not used as an independent input to the models. The results obtained demonstrate that: (1) the addition of the total flow rate as an input to the regression models can greatly improve the accuracy of water cut prediction, (2) the nonlinear SVR model performs much better than the linear LSR model, and (3) for the SVR model with the total flow rate as an input, the adoption of PCA or PLSA not only decreases the dimensions of inputs, but also increases prediction accuracy. The SVR model with five PCA-treated features plus the total flow rate achieves the best performance in water cut prediction, with a coefficient of determination (R 2 ) as high as 0.9970. The corresponding root mean squared error (RMSE) and mean quoted error (MQE) are 0.0312% and 1.99%, respectively. (paper)

  13. Ext The effect of littoralis leaf extract on Hemolytic Value (HC50 of mice

    Directory of Open Access Journals (Sweden)

    Zhi-jiang WANG

    2013-12-01

    Full Text Available Objective: To study the effect of Umbelliferae littoralis leaf extract on the Hemolytic Value (HC50 of mice, and to provide the basis for the development and utilization medicinal resources and edible resources. Methods: Prepare littoralis leaf water extract and alcohol extract, and set different dose treatment groups and blank control group, and continuously deliver American ginseng capsule for 15 days. Inject sRBC according to the weight on the tenth day. Take the blood serum from eyeball blood after 5 days. Put supernatant of 1ml and Dulbecco's reagent of 3ml in the test tube, and mix the 10% sRBC of 0.25ml and Dulbecco's reagent of 4ml together in another test tube, and measure absorbance at 540nm fine control (SA liquid tubing as blank, HC50 value were calculated. Results: Different extracts of stems and littoralis leaf were given to the mice for 15 days, and hemolytic value of the mice in water extract 4.68g/kg dose group, alcohol extract 4.68g/kg dose group and American ginseng capsule group significantly increased while comparing with the blank control group (P<0.05. Conclusion: Littoralis Leaf plays an important role in regulating human immunity.

  14. Hydraulic properties of rice and the response of gas exchange to water stress.

    Science.gov (United States)

    Stiller, Volker; Lafitte, H Renee; Sperry, John S

    2003-07-01

    We investigated the role of xylem cavitation, plant hydraulic conductance, and root pressure in the response of rice (Oryza sativa) gas exchange to water stress. In the field (Philippines), the percentage loss of xylem conductivity (PLC) from cavitation exceeded 60% in leaves even in watered controls. The PLC versus leaf water potential relationship indicated diurnal refilling of cavitated xylem. The leaf water potential causing 50 PLC (P(50)) was -1.6 MPa and did not differ between upland versus lowland rice varieties. Greenhouse-grown varieties (Utah) were more resistant to cavitation with a 50 PLC of -1.9 MPa but also showed no difference between varieties. Six-day droughts caused concomitant reductions in leaf-specific photosynthetic rate, leaf diffusive conductance, and soil-leaf hydraulic conductance that were associated with cavitation-inducing water potentials and the disappearance of nightly root pressure. The return of root pressure after drought was associated with the complete recovery of leaf diffusive conductance, leaf-specific photosynthetic rate, and soil-leaf hydraulic conductance. Root pressure after the 6-d drought (61.2 +/- 8.8 kPa) was stimulated 7-fold compared with well-watered plants before drought (8.5 +/- 3.8 kPa). The results indicate: (a) that xylem cavitation plays a major role in the reduction of plant hydraulic conductance during drought, and (b) that rice can readily reverse cavitation, possibly aided by nocturnal root pressure.

  15. Effects of leaf area index on the coupling between water table, land surface energy fluxes, and planetary boundary layer at the regional scale

    Science.gov (United States)

    Lu, Y.; Rihani, J.; Langensiepen, M.; Simmer, C.

    2013-12-01

    Vegetation plays an important role in the exchange of moisture and energy at the land surface. Previous studies indicate that vegetation increases the complexity of the feedbacks between the atmosphere and subsurface through processes such as interception, root water uptake, leaf surface evaporation, and transpiration. Vegetation cover can affect not only the interaction between water table depth and energy fluxes, but also the development of the planetary boundary layer. Leaf Area Index (LAI) is shown to be a major factor influencing these interactions. In this work, we investigate the sensitivity of water table, surface energy fluxes, and atmospheric boundary layer interactions to LAI as a model input. We particularly focus on the role LAI plays on the location and extent of transition zones of strongest coupling and how this role changes over seasonal timescales for a real catchment. The Terrestrial System Modelling Platform (TerrSysMP), developed within the Transregional Collaborative Research Centre 32 (TR32), is used in this study. TerrSysMP consists of the variably saturated groundwater model ParFlow, the land surface model Community Land Model (CLM), and the regional climate and weather forecast model COSMO (COnsortium for Small-scale Modeling). The sensitivity analysis is performed over a range of LAI values for different vegetation types as extracted from the Moderate Resolution Imaging Spectroradiometer (MODIS) dataset for the Rur catchment in Germany. In the first part of this work, effects of vegetation structure on land surface energy fluxes and their connection to water table dynamics are studied using the stand-alone CLM and the coupled subsurface-surface components of TerrSysMP (ParFlow-CLM), respectively. The interconnection between LAI and transition zones of strongest coupling are investigated and analyzed through a subsequent set of subsurface-surface-atmosphere coupled simulations implementing the full TerrSysMP model system.

  16. Rational Water and Nitrogen Management Improves Root Growth, Increases Yield and Maintains Water Use Efficiency of Cotton under Mulch Drip Irrigation

    Directory of Open Access Journals (Sweden)

    Hongzhi Zhang

    2017-05-01

    Full Text Available There is a need to optimize water-nitrogen (N applications to increase seed cotton yield and water use efficiency (WUE under a mulch drip irrigation system. This study evaluated the effects of four water regimes [moderate drip irrigation from the third-leaf to the boll-opening stage (W1, deficit drip irrigation from the third-leaf to the flowering stage and sufficient drip irrigation thereafter (W2, pre-sowing and moderate drip irrigation from the third-leaf to the boll-opening stage (W3, pre-sowing and deficit drip irrigation from the third-leaf to the flowering stage and sufficient drip irrigation thereafter (W4] and N fertilizer at a rate of 520 kg ha-1 in two dressing ratios [7:3 (N1, 2:8 (N2] on cotton root morpho-physiological attributes, yield, WUE and the relationship between root distribution and dry matter production. Previous investigations have shown a strong correlation between root activity and water consumption in the 40–120 cm soil layer. The W3 and especially W4 treatments significantly increased root length density (RLD, root volume density (RVD, root mass density (RMD, and root activity in the 40–120 cm soil layer. Cotton RLD, RVD, RMD was decreased by 13.1, 13.3, and 20.8%, respectively, in N2 compared with N1 at 70 days after planting (DAP in the 0–40 cm soil layer. However, root activity in the 40–120 cm soil layer at 140 DAP was 31.6% higher in N2 than that in N1. Total RMD, RLD and root activity in the 40–120 cm soil were significantly and positively correlated with shoot dry weight. RLD and root activity in the 40–120 cm soil layer was highest in the W4N2 treatments. Therefore increased water consumption in the deep soil layers resulted in increased shoot dry weight, seed cotton yield and WUE. Our data can be used to develop a water-N management strategy for optimal cotton yield and high WUE.

  17. Estimating contribution of anthocyanin pigments to osmotic adjustment during winter leaf reddening.

    Science.gov (United States)

    Hughes, Nicole M; Carpenter, Kaylyn L; Cannon, Jonathan G

    2013-01-15

    The association between plant water stress and synthesis of red, anthocyanin pigments in leaves has led some plant biologists to propose an osmotic function of leaf reddening. According to this hypothesis, anthocyanins function as a solute in osmotic adjustment (OA), contributing to depression of osmotic potential (Ψ(π)) and maintenance of turgor pressure during drought-stressed conditions. Here we calculate the percent contribution of anthocyanin to leaf Ψ(π) during OA in two angiosperm evergreen species, Galax urceolata and Gaultheria procumbens. Both species exhibit dramatic leaf reddening under high light during winter, concomitant with declines in leaf water potential and accumulation of solutes. Data previously published by the authors on osmotic potential at full turgor (Ψ(π,100)) of G. urceolata and G. procumbens leaves before and after leaf reddening were used to estimate OA. In vivo molar concentrations of anthocyanin, glucose, fructose, and sucrose measured from the same individuals were converted to pressure equivalents using the Ideal Gas Law, and percent contribution to OA was estimated. Estimated mean OA during winter was -0.7MPa for G. urceolata and -0.8MPa for G. procumbens. In vivo concentrations of anthocyanin (3-10mM) were estimated to account for ∼2% of OA during winter, and comprised <0.7% of Ψ(π,100) in both species. Glucose, fructose, and sucrose combined accounted for roughly 50 and 80% of OA for G. urceolata and G. procumbens, respectively, and comprised ∼20% of Ψ(π,100). We observed that a co-occurring, acyanic species (Vinca minor) achieved similar OA without synthesizing anthocyanin. We conclude that anthocyanins represent a measurable, albeit meager, component of OA in red-leafed evergreen species during winter. However, due to their low concentrations, metabolic costliness relative to other osmolytes, and striking red color (unnecessary for an osmotic function), it is unlikely that they are synthesized solely for an

  18. Phytohormones and microRNAs as sensors and regulators of leaf senescence: assigning macro roles to small molecules.

    Science.gov (United States)

    Sarwat, Maryam; Naqvi, Afsar Raza; Ahmad, Parvaiz; Ashraf, Muhammad; Akram, Nudrat Aisha

    2013-12-01

    Ageing or senescence is an intricate and highly synchronized developmental phase in the life of plant parts including leaf. Senescence not only means death of a plant part, but during this process, different macromolecules undergo degradation and the resulting components are transported to other parts of the plant. During the period from when a leaf is young and green to the stage when it senesces, a multitude of factors such as hormones, environmental factors and senescence associated genes (SAGs) are involved. Plant hormones including salicylic acid, abscisic acid, jasmonic acid and ethylene advance leaf senescence, whereas others like cytokinins, gibberellins, and auxins delay this process. The environmental factors which generally affect plant development and growth, can hasten senescence, the examples being nutrient dearth, water stress, pathogen attack, radiations, high temperature and light intensity, waterlogging, and air, water or soil contamination. Other important influences include carbohydrate accumulation and high carbon/nitrogen level. To date, although several genes involved in this complex process have been identified, still not much information exists in the literature on the signalling mechanism of leaf senescence. Now, the Arabidopsis mutants have paved our way and opened new vistas to elucidate the signalling mechanism of leaf senescence for which various mutants are being utilized. Recent studies demonstrating the role of microRNAs in leaf senescence have reinforced our knowledge of this intricate process. This review provides a comprehensive and critical analysis of the information gained particularly on the roles of several plant growth regulators and microRNAs in regulation of leaf senescence. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Effect of water stress on total biomass, tuber yield, harvest index and water use efficiency in Jerusalem artichoke

    Science.gov (United States)

    The objectives of this study were to determine the effect of drought on tuber yield, total biomass, harvest index, water use efficiency of tuber yield (WUEt) and water use efficiency of biomass (WUEb), and to evaluate the differential responses of Jerusalem artichoke (JA) varieties under drought str...

  20. Lantana Sp. leaf extracts for the control of Oulema Pectoralis Pest

    International Nuclear Information System (INIS)

    Ros Anita Ahmad Ramli; Nashriyah Mat; Salmah Moosa; Norimah Yusof; Zainab Harun; Maizatul Akmam Mohd Nasir; Misman Sumin; Rusli Zakaria

    2006-01-01

    This laboratory study was carried out to examine the effect of Lantana sp. leaf extracts on Oulema pectoralis mortality. Oulema pectoralis, the flower eating yellow beetle, is one of the most important pest of orchid. As this beetle feeds on orchid flower, the yield loss is 100 % due to zero tolerance to damage. Two different types of extraction were conducted, extraction with water and with organic solvent (ethanol). Five solutions of Lantana sp. extract were evaluated for their effectiveness against beetles. Water extract was prepared at concentrations of 5 % w/v, 10 % w/v and 20 % w/v; whilst organic solvent (ethanol) extract was prepared at concentrations of 5 % w/v and 10 % w/v. Ten replications were done for each treatment. Five adult O. pectoralis were placed on orchid flower painted with 1 mL test solution inside a glass beaker. Results showed that solution of Lantana sp. leaf extract was effective in controlling O. pectoralis beetle on orchid flower even at concentration as low as 10 % w/v (100 g of leaves blended with 1 litre of water or ethanol). (Author)