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Sample records for affects leaf surface

  1. Do leaf surface characteristics affect Agrobacterium infection in tea [Camellia sinensis (L.) O Kuntze]?

    Indian Academy of Sciences (India)

    Nitish Kumar; Subedar Pandey; Amita Bhattacharya; Paramvir Singh Ahuja

    2004-09-01

    The host range specificity of Agrobacterium with five tea cultivars and an unrelated species (Artemisia parviflora) having extreme surface characteristics was evaluated in the present study. The degree of Agrobacterium infection in the five cultivars of tea was affected by leaf wetness, micro-morphology and surface chemistry. Wettable leaf surfaces of TV1, Upasi-9 and Kangra jat showed higher rate (75%) of Agrobacterium infection compared to Upasi-10 and ST-449, whereas non-wettable leaves of A. parviflora showed minimum (25%) infection. This indicated that the leaves with glabrous surface having lower (larger surface area covered by water droplet), higher phenol and wax content were more suitable for Agrobacterium infection. Caffeine fraction of tea promoted Agrobacterium infection even in leaves poor in wax (Upasi-10), whereas caffeine-free wax inhibited both Agrobacterium growth and infection. Thus, study suggests the importance of leaf surface features in influencing the Agrobacterium infection in tea leaf explants. Our study also provides a basis for the screening of a clone/cultivar of a particular species most suitable for Agrobacterium infection the first step in Agrobacterium-mediated genetic transformation.

  2. 7 CFR 29.3528 - Leaf surface.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf surface. 29.3528 Section 29.3528 Agriculture... Type 95) § 29.3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf. Leaf surface is affected to some extent by the size and shrinkage of the veins or fibers (See...

  3. 7 CFR 29.3036 - Leaf surface.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf surface. 29.3036 Section 29.3036 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Leaf surface. The smoothness or roughness of the web or lamina of a tobacco leaf. Leaf surface...

  4. Silicified structures affect leaf optical properties in grasses and sedge.

    Science.gov (United States)

    Klančnik, Katja; Vogel-Mikuš, Katarina; Gaberščik, Alenka

    2014-01-05

    Silicon (Si) is an important structural element that can accumulate at high concentrations in grasses and sedges, and therefore Si structures might affect the optical properties of the leaves. To better understand the role of Si in light/leaf interactions in species rich in Si, we examined the total Si and silica phytoliths, the biochemical and morphological leaf properties, and the reflectance and transmittance spectra in grasses (Phragmites australis, Phalaris arundinacea, Molinia caerulea, Deschampsia cespitosa) and sedge (Carex elata). We show that these grasses contain >1% phytoliths per dry mass, while the sedge contains only 0.4%. The data reveal the variable leaf structures of these species and significant differences in the amount of Si and phytoliths between developing and mature leaves within each species and between grasses and sedge, with little difference seen among the grass species. Redundancy analysis shows the significant roles of the different near-surface silicified leaf structures (e.g., prickle hairs, cuticle, epidermis), phytoliths and Si contents, which explain the majority of the reflectance and transmittance spectra variability. The amount of explained variance differs between mature and developing leaves. The transmittance spectra are also significantly affected by chlorophyll a content and calcium levels in the leaf tissue.

  5. 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.

  6. Wettability and water uptake of holm oak leaf surfaces

    OpenAIRE

    2014-01-01

    Plant trichomes play important protective functions and may have a major influence on leaf surface wettability. With the aim of gaining insight into trichome structure, composition and function in relation to water-plant surface interactions, we analyzed the adaxial and abaxial leaf surface of Quercus ilex L. (holm oak) as model. By measuring the leaf water potential 24 h after the deposition of water drops on to abaxial and adaxial surfaces, evidence for water penetration through the upper l...

  7. 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, Pseud

  8. [XPS analysis of tea plant leaf and root surface].

    Science.gov (United States)

    Fang, Jiang-yu; Wan, Xiao-chun

    2008-09-01

    XPS was applied to analyze the surface chemical composition and structure of the tea plant leaf and root. It was detected that the surface is made up of mainly 4 elements: C, O, N and Al, with little P and F in abaxial leaf. Based on the botanic epidermis structure and the chemical composition, with the help of the standard spectrum data bank on line and the wood XPS study results, and through line Gaussian and Lorentizian the mixed, the binding energy of C(1s) of the leaf surface was classified as 3 types: the first was C1, with the electron binding energy of 285 eV, from C-C or C-H group, representing lipid compound like cutin and wax. C2 with the binding energy of 286.35 eV in the adaxial and 286.61 eV in the abaxial, came from the single bond of carbon and oxygen C-O, mainly standing for cellulose. C3 with the binding energy of approximately 288 eV (288.04 eV in adaxial and 288.09 eV in abaxial) was the sign of C=O group, which is acyl in protein with the confirmation of N(1s) (399-401 eV)and O(1s) analyses. In the root surface, besides the same compounds of cutin and wax (C1, binding energy 285 eV), cellulose (C2, binding energy 286.49 eV) and protein (C3, binding energy 288.78 eV)as in the leaf, there appeared C5 type with the binding energy of 283.32 eV. Because it was lower than C1, it was estimated as carbon linking to metal. Both the leaf and the root surfaces didn't have C4, a type of O-C=O, which is common in wood surface with the highest oxidated carbon of 289-289.5 eV binding energy, indicating that organic acid secreted by the root existed freely on the root surface, without any chemical association with the surface compounds. The results of the separated spectrum of O(1s) supported the above C(1s) results. By the ratio of each type of C, there were more oxygen groups in the abaxial than in the adaxial, implicating more active chemical properties on the abaxial. Compared with the leaf, cutin and wax was little in the root and oxygen groups were many

  9. Non-Smooth Morphologies of Typical Plant Leaf Surfaces and Their Anti-Adhesion Effects

    Institute of Scientific and Technical Information of China (English)

    Lu-quan Ren; Shu-jie Wang; Xi-mei Tian; Zhi-wu Han; Lin-na Yan; Zhao-mei Qiu

    2007-01-01

    The micromorphologies of surfaces of several typical plant leaves were investigated by scanning electron microscopy(SEM).Different non-smooth surface characteristics were described and classified.The hydrophobicity and anti-adhesion of non-smooth leaf surfaces were quantitatively measured.Results show that the morphology of epidermal cells and the morphology and distribution density of epicuticular wax directly affect the hydrophobicity and anti-adhesion.The surface with uniformly distributed convex units shows the best anti-adhesion,and the surface with regularly arranged trellis units displays better anti-adhesion.In contrast,the surface with randomly distributed hair units performs relatively bad anti-adhesion.The hydrophobic models of papilla-ciliary and fold-setal non-smooth surfaces were set up to determine the impacts of geometric parameters on the hydrophobicity.This study may provide an insight into surface machine molding and apparent morphology design for biomimetics engineering.

  10. Accumulation of particles on the surface of leaves during leaf expansion.

    Science.gov (United States)

    Wang, Lei; Gong, Huili; Liao, Wenbo; Wang, Zhi

    2015-11-01

    Plants can effectively remove airborne particles from ambient air and consequently improve air quality and human health. The accumulation of particles on the leaf surfaces of three plant species with different epicuticular wax ultrastructures, such as thin films, platelets and tubules, was investigated during leaf expansion in Beijing under extremely high particulate matter (PM) concentration. The accumulation of particles on the leaf surfaces after bud break rapidly reached a high amount within 4-7 days. Rainfall occasionally resulted in a considerable increase in the accumulation of particles on the leaf surfaces at a high PM concentration, which resulted from the wet deposition of PM, and balanced the amount of PM on the leaf surfaces over a longer period. The equilibrium value of the particle cover area on the adaxial leaf surface of the three test species in this study was 10%-50% compared with 3%-35% on the abaxial leaf surface. The epicuticular wax ultrastructures contributed significantly to the PM adsorption of the leaves. The capability of these ultrastructures to capture PM decreased in the following order: thin films, platelets and tubules. The ridges (at a scale of 1-2 μm) on the leaf surfaces were more efficient at accumulating PM, particularly PM2.5, compared with the roughness (P-V distance) at a 5-20-μm scale.

  11. Tadpoles of Early Breeding Amphibians are Negatively Affected by Leaf Litter From Invasive Chinese Tallow Trees

    Science.gov (United States)

    Leonard, N. E.

    2005-05-01

    As wetlands are invaded by Chinese tallow trees (Triadica sebifera), native trees are displaced and detrital inputs to amphibian breeding ponds are altered. I used a mesocosm experiment to examine the effect of Chinese tallow leaf litter on the survival to, size at, and time to metamorphosis of amphibian larvae. Fifty 1000-L cattle watering tanks were treated with 1500 g dry weight of one of five leaf litter treatments: Chinese tallow, laurel oak (Quercus laurifolia), water tupelo (Nyssa aquatica), slash pine (Pinus elliottii), or a 3:1:1:1 mixture. Each tank received 45 tadpoles of Pseudacris feriarum, Bufo terrestris, and Hyla cinerea in sequence according to their natural breeding phonologies. Every Pseudacris feriarum and Bufo terrestris tadpole exposed to Chinese tallow died prior to metamorphosis. Hyla cinerea survival in tanks with tallow-only was significantly lower than that observed for all other leaf treatments. Hyla cinerea tadpoles from tallow-only and mixed-leaf treatments were larger at metamorphosis and transformed faster than those in tanks with native leaves only. These results suggest that Chinese tallow leaf litter may negatively affect tadpoles of early breeding frogs and that Chinese tallow invasion may change the structure of amphibian communities in temporary ponds.

  12. Root cooling strongly affects diel leaf growth dynamics, water and carbohydrate relations in Ricinus communis.

    Science.gov (United States)

    Poiré, Richard; Schneider, Heike; Thorpe, Michael R; Kuhn, Arnd J; Schurr, Ulrich; Walter, Achim

    2010-03-01

    In laboratory and greenhouse experiments with potted plants, shoots and roots are exposed to temperature regimes throughout a 24 h (diel) cycle that can differ strongly from the regime under which these plants have evolved. In the field, roots are often exposed to lower temperatures than shoots. When the root-zone temperature in Ricinus communis was decreased below a threshold value, leaf growth occurred preferentially at night and was strongly inhibited during the day. Overall, leaf expansion, shoot biomass growth, root elongation and ramification decreased rapidly, carbon fluxes from shoot to root were diminished and carbohydrate contents of both root and shoot increased. Further, transpiration rate was not affected, yet hydrostatic tensions in shoot xylem increased. When root temperature was increased again, xylem tension reduced, leaf growth recovered rapidly, carbon fluxes from shoot to root increased, and carbohydrate pools were depleted. We hypothesize that the decreased uptake of water in cool roots diminishes the growth potential of the entire plant - especially diurnally, when the growing leaf loses water via transpiration. As a consequence, leaf growth and metabolite concentrations can vary enormously, depending on root-zone temperature and its heterogeneity inside pots.

  13. Evaporation and wetted area of single droplets on waxy and hairy leaf surfaces.

    Science.gov (United States)

    Zhu, H; Yu, Y; Ozkan, H E; Derksen, R C; Krause, C R

    2008-01-01

    Understanding the evaporation of pesticide droplets and wetting of Leaf surfaces can increase foliar application efficiency and reduce pesticide use. Evaporation time and wetted area of single pesticide droplets on hairy and waxy geranium leaf surfaces were measured under the controlled conditions for five droplet sizes and three relative humidities. The sprays used to form droplets included water, a nonionic colloidal polymer drift retardant, an alkyl polyoxyethylene surfactant, and an insecticide. Adding the surfactant into spray mixtures greatly increased droplet wetted area on the surfaces while droplet evaporation time was greatly reduced. Adding the drift retardant into spray mixture slightly increased the droplet evaporation time and the wetted area. Also, droplets had Longer evaporation times on waxy leaves than on hairy leaves for all droplet diameters and all relative humidity conditions. Increasing relative humidity could increase the droplet evaporation time greatly but did not change the the wetted area. The droplet evaporation time and wetted area increased exponentially as the droplet size increased. Therefore, droplet size, surface characteristics of the target, relative humidity, and chemical composition of the spray mixtures (water alone, pesticide, additives) should be included as important factors that affect the efficacy and efficiency of pesticide applications.

  14. Effects of CO/sub 2/ enrichment on internal leaf surface area in soybeans

    Energy Technology Data Exchange (ETDEWEB)

    Leadley, P.W.; Reynolds, J.A.; Thomas, J.F.; Reynolds, J.F.

    1987-06-01

    Internal cell surface areas were measured on fully expanded leaves of soybean seedlings that had been continuously exposed to 348 or 645 ppm CO/sub 2/ environments. Plants grown in the high CO/sub 2/ treatment had thicker leaves but less palisade cell surface area per unit of leaf area. Surface area of the mesophyll per unit leaf area was unaffected by CO/sub 2/. The potential ramifications of these CO/sub 2/-induced changes in leaf anatomy on photosynthesis and water-use efficiency are explored.

  15. Comparative Study of Leaf Surface Texture and Ability to Expand of Cured Tobacco

    Directory of Open Access Journals (Sweden)

    Rohr R

    2014-12-01

    Full Text Available Tobacco leaf texture, appreciated by the difference of surface roughness of cured leaves, is studies with light microscopy and scanning electron microscopy (SEM. The leaf texture is obviously determined by the presence or absence of conical cellular protuberances on the adaxial side of the leaf. Considering the anatomic point of view, the leaf thickness, always more important when the leaf texture is open, is the only objective criterion which could be associated to the texture. The ultra-structural study with SEM and transmission electron microscopy (TEM demonstrates that the expansion capacity of tobacco doesn't rely on cytological factors such as cellular reserves or debris. The expansion capacity could be inversely proportional with the relative importance of the mesophyll comparing to palisade parenchyma. On the studied material, no direct relation between the leaf texture and the expansion capacity has been noticed.

  16. Allometric analysis of the induced flavonols on the leaf surface of wild tobacco (Nicotiana attenuata).

    Science.gov (United States)

    Roda, Amy L; Oldham, Neil J; Svatos, Ales; Baldwin, Ian T

    2003-02-01

    Trichomes excrete secondary metabolites that may alter the chemical composition of the leaf surface, reducing damage caused by herbivores, pathogens and abiotic stresses. We examined the surface exudates produced by Nicotiana attenuata Torr. Ex Wats., a plant known to contain and secrete a number of secondary metabolites that are toxic or a deterrent to herbivorous insects. Extractions specific to the leaf surface, the trichomes, and the laminar components demonstrated the localization of particular compounds. Diterpene glycosides occurred exclusively in leaf mesophyll, whereas nicotine was found in both the trichomes and mesophyll. Neither rutin nor nicotine was found on the leaf surface. Quercetin and 7 methylated derivatives were found in the glandular trichomes and appeared to be excreted onto the leaf surface. We examined the elicitation of these flavonols on the leaf surface with a surface-area allometric analysis, which measures changes in metabolites independent of the effects of leaf expansion. The flavonols responded differently to wounding, methyl jasmonate (MeJA), herbivore attack and UV-C radiation, and the response patterns corresponded to their compound-specific allometries. Finding greater amounts of quercetin on younger leaves and reduced amounts after herbivore feeding and MeJA treatment, we hypothesized that quercetin may function as an attractant, helping the insects locate a preferred feeding site. Consistent with this hypothesis, mirids (Tupiocoris notatus) were found more often on mature leaves sprayed with quercetin at a concentration typical of young leaves than on unsupplemented mature leaves. The composition of metabolites on the leaf surface of N. attenuata changes throughout leaf development and in response to herbivore attack or environmental stress, and these changes are mediated in part by responses of the glandular trichomes.

  17. Apparent surface curvature affects lightness perception.

    Science.gov (United States)

    Knill, D C; Kersten, D

    1991-05-16

    The human visual system has the remarkable capacity to perceive accurately the lightness, or relative reflectance, of surfaces, even though much of the variation in image luminance may be caused by other scene attributes, such as shape and illumination. Most physiological, and computational models of lightness perception invoke early sensory mechanisms that act independently of, or before, the estimation of other scene attributes. In contrast to the modularity of lightness perception assumed in these models are experiments that show that supposedly 'higher-order' percepts of planar surface attributes, such as orientation, depth and transparency, can influence perceived lightness. Here we show that perceived surface curvature can also affect perceived lightness. The results of the earlier experiments indicate that perceiving luminance edges as changes in surface attributes other than reflectance can influence lightness. These results suggest that the interpretation of smooth variations in luminance can also affect lightness percepts.

  18. Seasonal Variability May Affect Microbial Decomposers and Leaf Decomposition More Than Warming in Streams.

    Science.gov (United States)

    Duarte, Sofia; Cássio, Fernanda; Ferreira, Verónica; Canhoto, Cristina; Pascoal, Cláudia

    2016-08-01

    Ongoing climate change is expected to affect the diversity and activity of aquatic microbes, which play a key role in plant litter decomposition in forest streams. We used a before-after control-impact (BACI) design to study the effects of warming on a forest stream reach. The stream reach was divided by a longitudinal barrier, and during 1 year (ambient year) both stream halves were at ambient temperature, while in the second year (warmed year) the temperature in one stream half was increased by ca. 3 °C above ambient temperature (experimental half). Fine-mesh bags containing oak (Quercus robur L.) leaves were immersed in both stream halves for up to 60 days in spring and autumn of the ambient and warmed years. We assessed leaf-associated microbial diversity by denaturing gradient gel electrophoresis and identification of fungal conidial morphotypes and microbial activity by quantifying leaf mass loss and productivity of fungi and bacteria. In the ambient year, no differences were found in leaf decomposition rates and microbial productivities either between seasons or stream halves. In the warmed year, phosphorus concentration in the stream water, leaf decomposition rates, and productivity of bacteria were higher in spring than in autumn. They did not differ between stream halves, except for leaf decomposition, which was higher in the experimental half in spring. Fungal and bacterial communities differed between seasons in both years. Seasonal changes in stream water variables had a greater impact on the activity and diversity of microbial decomposers than a warming regime simulating a predicted global warming scenario.

  19. Ontogenetic variation in chemical and physical characteristics of adaxial apple leaf surfaces.

    Science.gov (United States)

    Bringe, Katja; Schumacher, Christina F A; Schmitz-Eiberger, Michaela; Steiner, Ulrike; Oerke, Erich-Christian

    2006-01-01

    The reaction of plants to environmental factors often varies with developmental stage. It was hypothesized, that also the cuticle, the outer surface layer of plants is modified during ontogenesis. Apple plantlets, cv. Golden Delicious, were grown under controlled conditions avoiding biotic and abiotic stress factors. The cuticular wax surface of adaxial apple leaves was analyzed for its chemical composition as well as for its micromorphology and hydrophobicity just after unfolding of leaves ending in the seventh leaf insertion. The outer surface of apple leaves was formed by a thin amorphous layer of epicuticular waxes. Epidermal cells of young leaves exhibited a distinctive curvature of the periclinal cell walls resulting in an undulated surface of the cuticle including pronounced lamellae, with the highest density at the centre of cells. As epidermal cells expanded during ontogenesis, the upper surface showed only minor surface sculpturing and a decrease in lamellae. With increasing leaf age the hydrophobicity of adaxial leaf side decreased significantly indicated by a decrease in contact angle. Extracted from plants, the amount of apolar cuticular wax per area unit ranged from only 0.9 microgcm(-2) for the oldest studied leaf to 1.5 microgcm(-2) for the youngest studied leaf. Differences in the total amount of cuticular waxes per leaf were not significant for older leaves. For young leaves, triterpenes (ursolic acid and oleanolic acid), esters and alcohols were the main wax components. During ontogenesis, the proportion of triterpenes in total mass of apolar waxes decreased from 32% (leaf 1) to 13% (leaf 7); absolute amounts decreased by more than 50%. The proportion of wax alcohols and esters, and alkanes to a lesser degree, increased with leaf age, whereas the proportion of acids decreased. The epicuticular wax layer also contained alpha-tocopherol described for the first time to be present also in the epicuticular wax. The modifications in the chemical

  20. Relationship of 2 100-2 300 nm Spectral Characteristics of Wheat Canopy to Leaf Area Index and Leaf N as Affected by Leaf Water Content

    Institute of Scientific and Technical Information of China (English)

    ZHAO Chun-Jiang; WANG Ji-Hua; LIU Liang-Yun; HUANG Wen-Jiang; ZHOU Qi-Fa

    2006-01-01

    The effects of leaf water status in a wheat canopy on the accuracy of estimating leaf area index (LAI) and N were determined in this study using extracted spectral characteristics in the 2 000-2 300 nm region of the short wave infrared (SWI) band. A newly defined spectral index, relative adsorptive index in the 2 000-2 300 nm region (RAI2000-2300), which can be calculated by RAI2000-2300 = (R2224 - R2054) (R2224 + R2054)-1 with R being the reflectance at 2 224 or2 054 nm, was utilized. This spectral index, RAI2000-2300, was significantly correlated (P < 0.01) with green LAI and leaf N concentration and proved to be potentially valuable for monitoring plant green LAI and leaf N at the field canopy scale. Moreover, plant LAI could be monitored more easily and more successfully than plant leaf N. The study also showed that leaf water had a strong masking effect on the 2 000-2 300 nm spectral characteristics and both the coefficient between RAI2000-2300 and green LAI and that between RAI2000-2300 and leaf N content decreased as leaf water content increased.

  1. Role of leaf surface sugars in colonization of plants by bacterial epiphytes.

    Science.gov (United States)

    Mercier, J; Lindow, S E

    2000-01-01

    The relationship between nutrients leached onto the leaf surface and the colonization of plants by bacteria was studied by measuring both the abundance of simple sugars and the growth of Pseudomonas fluorescens on individual bean leaves. Data obtained in this study indicate that the population size of epiphytic bacteria on plants under environmentally favorable conditions is limited by the abundance of carbon sources on the leaf surface. Sugars were depleted during the course of bacterial colonization of the leaf surface. However, about 20% of readily utilizable sugar, such as glucose, present initially remained on fully colonized leaves. The amounts of sugars on a population of apparently identical individual bean leaves before and after microbial colonization exhibited a similar right-hand-skewed distribution and varied by about 25-fold from leaf to leaf. Total bacterial population sizes on inoculated leaves under conditions favorable for bacterial growth also varied by about 29-fold and exhibited a right-hand-skewed distribution. The amounts of sugars on leaves of different plant species were directly correlated with the maximum bacterial population sizes that could be attained on those species. The capacity of bacteria to deplete leaf surface sugars varied greatly among plant species. Plants capable of supporting high bacterial population sizes were proportionally more depleted of leaf surface nutrients than plants with low epiphytic populations. Even in species with a high epiphytic bacterial population, a substantial amount of sugar remained after bacterial colonization. It is hypothesized that residual sugars on colonized leaves may not be physically accessible to the bacteria due to limitations in wettability and/or diffusion of nutrients across the leaf surface.

  2. Increasing shrub abundance and N addition in Arctic tundra affect leaf and root litter decomposition differently

    Science.gov (United States)

    McLaren, J.; van de Weg, M. J.; Shaver, G. R.; Gough, L.

    2013-12-01

    Changes in global climate have resulted in a ';greening' of the Arctic as the abundance of deciduous shrub species increases. Consequently, not only the living plant community, but also the litter composition changes, which in turn can affect carbon turnover patterns in the Arctic. We examined effects of changing litter composition (both root and leaf litter) on decomposition rates with a litter bag study, and specifically focused on the impact of deciduous shrub Betula nana litter on litter decomposition from two evergreen shrubs (Ledum palustre, and Vaccinium vitis-idaea) and one graminoid (Eriophorum vaginatum) species. Additionally, we investigated how decomposition was affected by nutrient availability by placing the litterbags in an ambient and a fertilized moist acidic tundra environment. Measurements were carried out seasonally over 2 years (after snow melt, mid-growing season, end growing season). We measured litter mass loss over time, as well as the respiration rates (standardized for temperature and moisture) and temperature sensitivity of litter respiration at the time of harvesting the litter bags. For leaves, Betula litter decomposed faster than the other three species, with Eriophorum leaves decomposing the slowest. This pattern was observed for both mass loss and litter respiration rates, although the differences in respiration became smaller over time. Surprisingly, combining Betula with any other species resulted in slower overall weight loss rates than would be predicted based on monoculture weight loss rates. This contrasted with litter respiration at the time of sampling, which showed a positive mixing effect of adding Betula leaf liter to the other species. Apparently, during the first winter months (September - May) Betula litter decomposition is negatively affected by mixing the species and this legacy can still be observed in the total mass loss results later in the year. For root litter there were fewer effects of species identity on root

  3. Plant species differences in particulate matter accumulation on leaf surfaces.

    Science.gov (United States)

    Sæbø, A; Popek, R; Nawrot, B; Hanslin, H M; Gawronska, H; Gawronski, S W

    2012-06-15

    Particulate matter (PM) accumulation on leaves of 22 trees and 25 shrubs was examined in test fields in Norway and Poland. Leaf PM in different particle size fractions (PM(10), PM(2.5), PM(0.2)) differed among the species, by 10- to 15-folds at both test sites. Pinus mugo and Pinus sylvestris, Taxus media and Taxus baccata, Stephanandra incisa and Betula pendula were efficient species in capturing PM. Less efficient species were Acer platanoides, Prunus avium and Tilia cordata. Differences among species within the same genus were also observed. Important traits for PM accumulation were leaf properties such as hair and wax cover. The ranking presented in terms of capturing PM can be used to select species for air pollution removal in urban areas. Efficient plant species and planting designs that can shield vulnerable areas in urban settings from polluting traffic etc. can be used to decrease human exposure to anthropogenic pollutants.

  4. How does the VPD response of isohydric and anisohydric plants depend on leaf surface particles?

    Science.gov (United States)

    Burkhardt, J; Pariyar, S

    2016-01-01

    Atmospheric vapour pressure deficit (VPD) is the driving force for plant transpiration. Plants have different strategies to respond to this 'atmospheric drought'. Deposited aerosols on leaf surfaces can interact with plant water relations and may influence VPD response. We studied transpiration and water use efficiency of pine, beech and sunflower by measuring sap flow, gas exchange and carbon isotopes, thereby addressing different time scales of plant/atmosphere interaction. Plants were grown (i) outdoors under rainfall exclusion (OD) and in ventilated greenhouses with (ii) ambient air (AA) or (iii) filtered air (FA), the latter containing plants were sprayed once with 25 mM salt solution of (NH4 )2 SO4 or NaNO3 . Carbon isotope values (δ(13) C) became more negative in the presence of more particles; more negative for AA compared to FA sunflower and more negative for OD Scots pine compared to other growth environments. FA beech had less negative δ(13) C than AA, OD and NaNO3 -treated beech. Anisohydric beech showed linearly increasing sap flow with increasing VPD. The slopes doubled for (NH4 )2 SO4 - and tripled for NaNO3 -sprayed beech compared to control seedlings, indicating decreased ability to resist atmospheric demand. In contrast, isohydric pine showed constant transpiration rates with increasing VPD, independent of growth environment and spray, likely caused by decreasing gs with increasing VPD. Generally, NaNO3 spray had stronger effects on water relations than (NH4 )2 SO4 spray. The results strongly support the role of leaf surface particles as an environmental factor affecting plant water use. Hygroscopic and chaotropic properties of leaf surface particles determine their ability to form wicks across stomata. Such wicks enhance unproductive water loss of anisohydric plant species and decrease CO2 uptake of isohydric plants. They become more relevant with increasing number of fine particles and increasing VPD and are thus related to air pollution and

  5. Diversity and Composition of the Leaf Mycobiome of Beech (Fagus sylvatica) Are Affected by Local Habitat Conditions and Leaf Biochemistry.

    Science.gov (United States)

    Unterseher, Martin; Siddique, Abu Bakar; Brachmann, Andreas; Peršoh, Derek

    2016-01-01

    Comparative investigations of plant-associated fungal communities (mycobiomes) in distinct habitats and under distinct climate regimes have been rarely conducted in the past. Nowadays, high-throughput sequencing allows routine examination of mycobiome responses to environmental changes and results at an unprecedented level of detail. In the present study, we analysed Illumina-generated fungal ITS1 sequences from European beech (Fagus sylvatica) originating from natural habitats at two different altitudes in the German Alps and from a managed tree nursery in northern Germany. In general, leaf-inhabiting mycobiome diversity and composition correlated significantly with the origin of the trees. Under natural condition the mycobiome was more diverse at lower than at higher elevation, whereas fungal diversity was lowest in the artificial habitat of the tree nursery. We further identified significant correlation of leaf chlorophylls and flavonoids with both habitat parameters and mycobiome biodiversity. The present results clearly point towards a pronounced importance of local stand conditions for the structure of beech leaf mycobiomes and for a close interrelation of phyllosphere fungi and leaf physiology.

  6. Physicochemical characteristics of ambient particles settling upon leaf surfaces of urban plants in Beijing

    Institute of Scientific and Technical Information of China (English)

    WANG Lei; LIU Lian-you; GAO Shang-yu; HASI Eer-dun; WANG Zhi

    2006-01-01

    Particulate pollution is a serious health problem throughout the world, exacerbating a wide range of respiratory and vascular illnesses in urban areas. Urban plants play an important role in reducing particulate pollution. Physicochemical characteristics of ambient particles settling upon leaf surfaces of eleven roadside plants at four sites of Beijing were studies. Results showed that density of particles on the leaf surfaces greatly varied with plant species and traffic condition. Fraxinus chinensis, Sophora japonica, Ailanthus altissima, Syringa oblata and Prunus persica had larger densities of particles among the tall species. Due to resuspension of road dust,the densities of particles ofEuonymus japonicus and Parthenocissus quinquefolia with low sampling height were 2-35 times to other taller tree species. For test plant species, micro-roughness of leaf surfaces and density of particles showed a close correlation. In general, the larger micro-roughness of leaf surfaces is, the larger density of particles is. Particles settling upon leaf surfaces were dominantly PM10 (particulate matter less than 10 μm in aerodynamic diameter; 98.4%) and PM2.5 (particulate matter less than 2.5 μm in aerodynamic diameter; 64.2%) which were closely relative to human health. Constant elements of particles were C, O, K, Ca, Si,earth dust or industrial emission and SO2, H2SO4 or sulfate. NaCl was derived from sea salt.

  7. Evaluation of Surface anesthetic action of Aqueous Extract of Piper Betel leaf On Rabbit Cornea

    Directory of Open Access Journals (Sweden)

    Dr.T.Jayasree

    2014-07-01

    Full Text Available Aim: Piper betel Linn. (Piperaceae commonly known as betel leaf and the habit of betel chewing is widely prevalent in most parts of India. It is claimed to have aphrodisiac, laxative, antimicrobial, mucolytic, antiinflammatory and euphoric properties and proven antimutagenic and anti-carcinogenic effect. It is commonly observed that chewing of betel leaf produces numbness in the mouth, suggesting a possible local anesthetic effect. This observation prompted us to take this study . The aim of the study was to evaluate the local anesthetic activity of betel leaf extract after autoclaving the extract of betel leaf. Materials and methods: Extract of plain betel leaf, was tested for surface anesthetic activity using rabbits. Aqueous extraction of Piper betel leaf (AEPBL done by Soxhelts apparatus .Twenty male Rabbit’s were taken and divided in to four groups each group contain 5 animals, Group I - Standard (2% xylocaine, Group II - Test 0.3% (AEPBL, Group III - Test 0.6 % (AEPBL,Group IV - Test 12 % (AEPBL was instilled in conjunctival sac of right eyes. Standard protocol was followed to elicit light reflex, corneal reflex and to measure pupillary size after instilling the test drugs in the eye. There was dose dependent increase in onset and duration of local anesthetic activity with 6% and 12% doses of alcoholic extract of Piper betel leaf. Results: Betel leaf showed significant surface anesthetic activity comparable to that of Xylocaine. Conclusion: As a surface anesthetic, the onset was as quick as xylocaine and the duration was shorter than xylocaine

  8. Defending the leaf surface: intra- and inter-specific differences in silicon deposition in grasses in response to damage and silicon supply

    Directory of Open Access Journals (Sweden)

    Sue Elaine Hartley

    2015-02-01

    Full Text Available Understanding interactions between grasses and their herbivores is central to the conservation of species-rich grasslands and the protection of our most important crops against pests. Grasses employ a range of defenses against their natural enemies; silicon-based defenses have been shown to be one of the most effective. Silicon (Si is laid down on the leaf surface as spines and other sharp bodies, known as phytoliths, making grasses abrasive and their foliage indigestible to herbivores. Previous studies on Si defenses found that closely related species may have similar levels of Si in the leaves but differ markedly in abrasiveness. Here we show how the number, shape and distribution of Si-rich phytoliths and spines differ within and between different grass species and demonstrate that species also differ in their ability to change the deposition and distribution of these defenses in response to damage or increases in Si supply. Specifically, we tested the response of two genotypes of Festuca arundinacea known to differ in their surface texture and 3 different grass species (F. ovina, F. rubra and Deschampsia cespitosa differing in their abrasiveness to combined manipulation of leaf damage and Si supply. F.arundinacea plants with a harsh leaf surface had higher Si content and more spines on their leaf surface than soft varieties. F. ovina and D. cespitosa plants increased their leaf Si concentration and produced an increase in the number of leaf spines and phytoliths on the leaf surface in response to Si addition. F rubra also increased leaf Si content in response to treatments, particularly in damaged leaves, but did not deposit this in the form of spines or increased densities of phytoliths. We discuss how the form in which grasses deposit Si may affect their anti-herbivore characteristics and consider the ecological and agricultural implications of the differences in allocation to Si-based defenses between grass species.

  9. Defending the leaf surface: intra- and inter-specific differences in silicon deposition in grasses in response to damage and silicon supply.

    Science.gov (United States)

    Hartley, Sue E; Fitt, Rob N; McLarnon, Emma L; Wade, Ruth N

    2015-01-01

    Understanding interactions between grasses and their herbivores is central to the conservation of species-rich grasslands and the protection of our most important crops against pests. Grasses employ a range of defenses against their natural enemies; silicon-based defenses have been shown to be one of the most effective. Silicon (Si) is laid down on the leaf surface as spines and other sharp bodies, known as phytoliths, making grasses abrasive and their foliage indigestible to herbivores. Previous studies on Si defenses found that closely related species may have similar levels of Si in the leaves but differ markedly in abrasiveness. Here we show how the number, shape and distribution of Si-rich phytoliths and spines differ within and between different grass species and demonstrate that species also differ in their ability to change the deposition and distribution of these defenses in response to damage or increases in Si supply. Specifically, we tested the response of two genotypes of Festuca arundinacea known to differ in their surface texture and three different grass species (F. ovina, F. rubra, and Deschampsia cespitosa) differing in their abrasiveness to combined manipulation of leaf damage and Si supply. F. arundinacea plants with a harsh leaf surface had higher Si content and more spines on their leaf surface than soft varieties. F. ovina and D. cespitosa plants increased their leaf Si concentration and produced an increase in the number of leaf spines and phytoliths on the leaf surface in response to Si addition. F rubra also increased leaf Si content in response to treatments, particularly in damaged leaves, but did not deposit this in the form of spines or increased densities of phytoliths. We discuss how the form in which grasses deposit Si may affect their anti-herbivore characteristics and consider the ecological and agricultural implications of the differences in allocation to Si-based defenses between grass species.

  10. Piper betle leaf extract affects the quorum sensing and hence virulence of Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Datta, Siraj; Jana, Debanjan; Maity, Tilak Raj; Samanta, Aveek; Banerjee, Rajarshi

    2016-06-01

    Quorum sensing (QS) plays an important role in virulence of Pseudomonas aeruginosa, blocking of QS ability are viewed as viable antimicrobial chemotherapy and which may prove to be a safe anti-virulent drug. Bioactive components from Piper betle have been reported to possess antimicrobial ability. This study envisages on the anti-QS properties of ethanolic extract of P. betle leaf (PbLE) using P. aeruginosa PAO1 as a model organism. A marked reduction in swarming, swimming, and twitching ability of the bacteria is demonstrated in presence of PbLE. The biofilm and pyocyanin production also shows a marked reduction in presence of PbLE, though it does not affect the bacterial growth. Thus, the studies hint on the possible effect of the bioactive components of PbLE on reducing the virulent ability of the bacteria; identification of bioactive compounds should be investigated further.

  11. Factors Affecting Leaf Selection by Foregut-fermenting Proboscis Monkeys: New Insight from in vitro Digestibility and Toughness of Leaves

    Science.gov (United States)

    Matsuda, Ikki; Clauss, Marcus; Tuuga, Augustine; Sugau, John; Hanya, Goro; Yumoto, Takakazu; Bernard, Henry; Hummel, Jürgen

    2017-01-01

    Free-living animals must make dietary choices in terms of chemical and physical properties, depending on their digestive physiology and availability of food resources. Here we comprehensively evaluated the dietary choices of proboscis monkeys (Nasalis larvatus) consuming young leaves. We analysed the data for leaf toughness and digestibility measured by an in vitro gas production method, in addition to previously reported data on nutrient composition. Leaf toughness, in general, negatively correlated with the crude protein content, one of the most important nutritional factors affecting food selection by leaf-eating primates. This result suggests that leaf toughness assessed by oral sensation might be a proximate cue for its protein content. We confirmed the importance of the leaf chemical properties in terms of preference shown by N. larvatus; leaves with high protein content and low neutral detergent fibre levels were preferred to those of the common plant species. We also found that these preferred leaves were less tough and more digestible than the alternatives. Our in vitro results also suggested that N. larvatus were little affected by secondary plant compounds. However, the spatial distribution pattern of plant species was the strongest factor explaining the selection of the preferred leaf species. PMID:28211530

  12. Factors Affecting Leaf Selection by Foregut-fermenting Proboscis Monkeys: New Insight from in vitro Digestibility and Toughness of Leaves.

    Science.gov (United States)

    Matsuda, Ikki; Clauss, Marcus; Tuuga, Augustine; Sugau, John; Hanya, Goro; Yumoto, Takakazu; Bernard, Henry; Hummel, Jürgen

    2017-02-17

    Free-living animals must make dietary choices in terms of chemical and physical properties, depending on their digestive physiology and availability of food resources. Here we comprehensively evaluated the dietary choices of proboscis monkeys (Nasalis larvatus) consuming young leaves. We analysed the data for leaf toughness and digestibility measured by an in vitro gas production method, in addition to previously reported data on nutrient composition. Leaf toughness, in general, negatively correlated with the crude protein content, one of the most important nutritional factors affecting food selection by leaf-eating primates. This result suggests that leaf toughness assessed by oral sensation might be a proximate cue for its protein content. We confirmed the importance of the leaf chemical properties in terms of preference shown by N. larvatus; leaves with high protein content and low neutral detergent fibre levels were preferred to those of the common plant species. We also found that these preferred leaves were less tough and more digestible than the alternatives. Our in vitro results also suggested that N. larvatus were little affected by secondary plant compounds. However, the spatial distribution pattern of plant species was the strongest factor explaining the selection of the preferred leaf species.

  13. Do variations in leaf phenology affect radial growth variations in Fagus sylvatica?

    Science.gov (United States)

    Čufar, Katarina; De Luis, Martin; Prislan, Peter; Gričar, Jožica; Črepinšek, Zalika; Merela, Maks; Kajfež-Bogataj, Lučka

    2015-08-01

    We used a dendrochronological and leaf phenology network of European beech (Fagus sylvatica) in Slovenia, a transitional area between Mediterranean, Alpine and continental climatic regimes, for the period 1955-2007 to test whether year to year variations in leaf unfolding and canopy duration (i.e. time between leaf unfolding and colouring) influence radial growth (annual xylem production and tree ring widths) and if such influences are more pronounced at higher altitudes. We showed that variability in leaf phenology has no significant effect on variations in radial growth. The results are consistent in the entire region, irrespective of the climatic regime or altitude, although previous studies have shown that leaf phenology and tree ring variation depend on altitude. The lack of relationship between year to year variability in leaf phenology and radial growth may suggest that earlier leaf unfolding--as observed in a previous study--probably does not cause increased tree growth rates in beech in Slovenia.

  14. Do variations in leaf phenology affect radial growth variations in Fagus sylvatica?

    Science.gov (United States)

    Čufar, Katarina; De Luis, Martin; Prislan, Peter; Gričar, Jožica; Črepinšek, Zalika; Merela, Maks; Kajfež-Bogataj, Lučka

    2015-08-01

    We used a dendrochronological and leaf phenology network of European beech ( Fagus sylvatica) in Slovenia, a transitional area between Mediterranean, Alpine and continental climatic regimes, for the period 1955-2007 to test whether year to year variations in leaf unfolding and canopy duration (i.e. time between leaf unfolding and colouring) influence radial growth (annual xylem production and tree ring widths) and if such influences are more pronounced at higher altitudes. We showed that variability in leaf phenology has no significant effect on variations in radial growth. The results are consistent in the entire region, irrespective of the climatic regime or altitude, although previous studies have shown that leaf phenology and tree ring variation depend on altitude. The lack of relationship between year to year variability in leaf phenology and radial growth may suggest that earlier leaf unfolding—as observed in a previous study—probably does not cause increased tree growth rates in beech in Slovenia.

  15. Age-related leaf characteristics of surface features and ultrastructure of Dendropanax morbifera.

    Science.gov (United States)

    Kim, Ki Woo; Koo, Young Kuk; Yoon, Chul Jong

    2012-02-01

    Age-related morphological and anatomical changes were investigated by light and electron microscopy with juvenile and adult leaves of Dendropanax morbifera. Most juvenile leaves were glossy and palmate with five deep and narrow lobes divided nearly to two-thirds of the leaf base. Adult leaves were thick and possessed three lobes divided nearly to half of the leaf base. Stomata were ovoid and found on the abaxial surface. The epicuticular waxes of the plant included platelets, angular rodlets and threads. Platelets were attached to the surface at various angles. Distinct angular rodlets could be found on either the adaxial or the abaxial surface. Platelets on surface undulations occurred exclusively on the abaxial surface of adult leaves. Juvenile leaves were ca. 150 μm thick and had few intercellular spaces. Adult leaves were nearly two times thicker than juvenile leaves, and showed highly vacuolated cells and large intercellular spaces. The cuticle proper was apparent on the epidermis and showed distinctly alternating lamellate structures in juvenile leaves. The epidermal cell wall of adult leaves was covered with a cuticle layer for which a lamellate structure was not found. These results suggest that the species is heteroblastic in leaf characteristics with increasing leaf age.

  16. Orientation of Germ Tubes of Puccinia hordei on the Hordeum chilense Leaf Surface

    NARCIS (Netherlands)

    Vaz Patto, M.C.; Niks, R.E.

    2000-01-01

    The directional growth of urediospores germ tubes along the transverse axis of a cereal's leaf is considered to be a response to stimuli from the plant surface. In order to find out if the germ tube growth is directed towards stomata, and if the cuticular wax layer plays a role in this orientated gr

  17. Photosynthetic responses to leaf surface wetness in tropical plant species of Costa Rica with varying leaf traits

    Science.gov (United States)

    Aparecido, L. M. T.; Moore, G. W.; Miller, G. R.; Cahill, A. T.

    2015-12-01

    Wet tropical forests are some of the environments with the greatest annual precipitation, but are also considered as the world's major carbon sink; however, literature postulates that phothsynthesis rates are inhibited while leaves are wet. Yet measurements of photosynthesis during wet conditions are challenging to obtain due to equipment limitations and the extreme complexity of canopy-atmosphere interactions in tropical environments. The objective of this study was to evaluate tropical species reactions to simulated leaf wetness and test the hypothesis that leaf wetness reduces rates of photosynthesis. In a central Costa Rica site with an average 4200 mm annual rainfall, we selected six tropical species with distinct leaf traits in which five sun-exposed leaf replicates from each species were subjected to gas exchange measurements using a LI-6400 IRGA (LICOR Inc., Lincoln, NE) under dry and wet/misted leaf conditions. Relationships between photosynthesis (As) and stomatal conductance (gs) with leaf to air temperature difference (DT), VPD, and relative humidity were evaluated using linear regression analysis. We found that the responses varied greatly among species, but all plants maintained a baseline of activity under wet leaf conditions, suggesting that abaxial leaf As was a significant percentage of total leaf As. Stachytarpheta jamaicens had an 18.7% reduction in As, while others, like Zamia skinneri, had a 7% increase in As. Tibouchina heteromalla showed a rapid stomatal recovery of 2 mins, while Carapa guianensis was slower with 7 mins. This variability between species suggests that leaf traits, such as presence or absence of trichomes, water repellency, vein distribution and size and leaf angle variation, may be critical for optimizing photosynthesis under wet conditions. Relative humidity and leaf temperature were the strongest secondary influences on As and gs under wet leaf conditions. While tropical vegetation-atmosphere interactions are complex, such

  18. Reactive uptake of ozone at simulated leaf surfaces: implications for ‘non-stomatal’ ozone deposition.

    OpenAIRE

    Cape, J. Neil; Hamilton, Richard; Heal, Mathew R

    2009-01-01

    The reaction of ozone (O3) with alpha-pinene has been studied as a function of temperature and relative humidity and in the presence of wax surfaces that simulate a leaf surface. The objective was to determine whether the presence of a wax surface, in which alpha-pinene could dissolve and form a high surface concentration, would lead to enhanced reaction with O3. The reaction of O3 itself with the empty stainless steel reactor and with aluminium and wax surfaces demonstrated an apparent activ...

  19. Carbonized-leaf Membrane with Anisotropic Surfaces for Sodium-ion Battery.

    Science.gov (United States)

    Li, Hongbian; Shen, Fei; Luo, Wei; Dai, Jiaqi; Han, Xiaogang; Chen, Yanan; Yao, Yonggang; Zhu, Hongli; Fu, Kun; Hitz, Emily; Hu, Liangbing

    2016-01-27

    A simple one-step thermal pyrolysis route has been developed to prepare carbon membrane from a natural leaf. The carbonized leaf membrane possesses anisotropic surfaces and internal hierarchical porosity, exhibiting a high specific capacity of 360 mAh/g and a high initial Coulombic efficiency of 74.8% as a binder-free, current-collector-free anode for rechargeable sodium ion batteries. Moreover, large-area carbon membranes with low contact resistance are fabricated by simply stacking and carbonizing leaves, a promising strategy toward large-scale sodium-ion battery developments.

  20. Adhesion of pineapple-leaf fiber to epoxy matrix: The role of surface treatments

    Directory of Open Access Journals (Sweden)

    Yusran Payae

    2009-07-01

    Full Text Available Natural fibers are considered to have potential use as reinforcing agents in polymer composite materials because of their principle benefits: moderate strength and stiffness, low cost, and be an environmental friendly, degradable, and renewablematerial. Due to their inherently hydrophilic nature, they are prone to absorb moisture, which can plasticise or weaken theadhesion of fibers to the surrounding matrix and by this affect the performance of composites used in atmospheric humidity,particularly at elevated temperatures. The surface treatments are often applied to the fiber to improve the bond strengthbetween the fibers and matrix. This work discussed the effect of sodium hydroxide (NaOH treatment and epoxy resin as acompatibilizing agent on interface properties of pineapple leaf fiber (PALF-epoxy composites. A single-fiber fragmentationtest coupled with data reduction technique was employed to assess interface quality in terms of apparent interfacial shearstrength (IFSS or a of untreated, NaOH, and epoxy resin treated PALFs-epoxy composites. Tensile properties of untreatedand treated PALFs were also examined. It was found that both treatments substantially increase a, corresponding to animproved level of adhesion. The improvement in the level of adhesion for the alkali and epoxy treated fiber composites wasdue to an increase in the physical bonding between the alkali treated fibers and the matrix, and due to a promoted compatibilitybetween the epoxy treated fibers and matrix, respectively.

  1. Biaxially stretchable silver nanowire conductive film embedded in a taro leaf-templated PDMS surface

    Science.gov (United States)

    Wu, Chunhui; Jiu, Jinting; Araki, Teppei; Koga, Hirotaka; Sekitani, Tsuyoshi; Wang, Hao; Suganuma, Katsuaki

    2017-01-01

    A biaxially wave-shaped polydimethylsiloxane (PDMS) surface was developed simply by using a taro leaf as the template. The resulting leaf-templated PDMS (L-PDMS) possesses a micro-sized curved interface structure, which is greatly beneficial for the exact embedding of a silver nanowire (AgNW) network conductive film covering the L-PDMS surface. The intrinsically curved AgNW/L-PDMS film surface, without any dangling nanowire, could prevent the fracture of AgNWs due to stretching stress even after cyclic stretching. More importantly, it also exhibited a biaxial stretchability, which showed ultra-stable resistance after continuous stretching for 100 cycles each in X- and Y-directions. This biaxially stretchable AgNW/L-PDMS film could extend the application fields in stretchable electronics.

  2. Wettability and morphology of the leaf surface in cashew tree from the Amazon, Northern Brazil

    Directory of Open Access Journals (Sweden)

    Glenda Quaresma Ramos

    2016-10-01

    Full Text Available Leaves surfaces, which represent an interface with plants and the environment, have several structures with specific functions. Some foliar properties, including wettability and mechanical containment, are inferred in terms of cellular adaptation and the presence or absence of cuticular wax. Various morphological parameters, ranging from macro- to nano scales, are analyzed and contribute to the study of taxonomy, pharmacognosy, and ecology of plants. The aim of this paper was to analyze the effect and influence of epicuticular wax granules on the hydrophobicity of Anacardium occidentale L. leaf surfaces. Leaf specimens were directly examined with an environmental scanning electron microscope without metal coating. Images revealed epidermis ornament, stomata type, was, and trichomes. Static contact angle between water and the surface was also measured on both sides. On the adaxial side, an angle of 104.09° ± 0.95° was found, suggesting that adaxial surface is hydrophobic. On the abaxial side, the angle was 62.20° ± 1.60°, which indicates a hydrophilic nature, probably because of the greater amount of epicuticular wax on the adaxial leaf surface. The present investigation provided an important contribution to morphological and ultrastructural characterization of leaves of cashew tree, which is a plant of great medicinal and economic importance.

  3. 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

  4. Climatic factors influence leaf structure and thereby affect the ozone sensitivity of Ipomoea nil 'Scarlet O'Hara'.

    Science.gov (United States)

    Moura, Bárbara B; Alves, Edenise S

    2014-11-01

    Phenotypic plasticity of the leaves can interfere with the plant sensitivity to ozone (O3) toxic effect. This study aimed to assess whether the leaf structure of Ipomoea nil changes due to climatic variations and whether these changes affect the species' sensitivity. Field exposures, in different seasons (winter and spring) were made. The leaves that developed during the winter were thinner, with a lower proportion of photosynthetic tissues, higher proportion of intercellular spaces and lower density and stomatal index compared to those developed during the spring. The temperature and relative humidity positively influenced the leaf thickness and stomatal index. The visible injuries during winter were positively correlated with the palisade parenchyma thickness and negatively correlated with the percentage of spongy parenchyma; during the spring, the symptoms were positively correlated with the stomatal density. In conclusion, the leaf structure of I. nil varied among the seasons, interfering in its sensitivity to O3.

  5. ATP-binding cassette transporter controls leaf surface secretion of anticancer drug components in Catharanthus roseus.

    Science.gov (United States)

    Yu, Fang; De Luca, Vincenzo

    2013-09-24

    The Madagascar periwinkle (Catharanthus roseus) is highly specialized for the biosynthesis of many different monoterpenoid indole alkaloids (MIAs), many of which have powerful biological activities. Such MIAs include the commercially important chemotherapy drugs vinblastine, vincristine, and other synthetic derivatives that are derived from the coupling of catharanthine and vindoline. However, previous studies have shown that biosynthesis of these MIAs involves extensive movement of metabolites between specialized internal leaf cells and the leaf epidermis that require the involvement of unknown secretory processes for mobilizing catharanthine to the leaf surface and vindoline to internal leaf cells. Spatial separation of vindoline and catharanthine provides a clear explanation for the low levels of dimers that accumulate in intact plants. The present work describes the molecular cloning and functional identification of a unique catharanthine transporter (CrTPT2) that is expressed predominantly in the epidermis of young leaves. CrTPT2 gene expression is activated by treatment with catharanthine, and its in planta silencing redistributes catharanthine to increase the levels of catharanthine-vindoline drug dimers in the leaves. Phylogenetic analysis shows that CrTPT2 is closely related to a key transporter involved in cuticle assembly in plants and that may be unique to MIA-producing plant species, where it mediates secretion of alkaloids to the plant surface.

  6. Leaf biomechanical properties in Arabidopsis thaliana polysaccharide mutants affect drought survival.

    Science.gov (United States)

    Balsamo, Ronald; Boak, Merewyn; Nagle, Kayla; Peethambaran, Bela; Layton, Bradley

    2015-11-26

    Individual sugars are the building blocks of cell wall polysaccharides, which in turn comprise a plant׳s overall architectural structure. But which sugars play the most prominent role in maintaining a plant׳s mechanical stability during large cellular deformations induced by drought? We investigated the individual contributions of several genes that are involved in the synthesis of monosaccharides which are important for cell wall structure. We then measured drought tolerance and mechanical integrity during simulated drought in Arabidopsis thaliana. To assess mechanical properties, we designed a small-scale tensile tester for measuring failure strain, ultimate tensile stress, work to failure, toughness, and elastic modulus of 6-week-old leaves in both hydrated and drought-simulated states. Col-0 mutants used in this study include those deficient in lignin, cellulose, components of hemicellulose such as xylose and fucose, the pectic components arabinose and rhamnose, as well as mutants with enhanced arabinose and total pectin content. We found that drought tolerance is correlated to the mechanical and architectural stability of leaves as they experience dehydration. Of the mutants, S096418 with mutations for reduced xylose and galactose was the least drought tolerant, while the arabinose-altered CS8578 mutants were the least affected by water loss. There were also notable correlations between drought tolerance and mechanical properties in the diminished rhamnose mutant, CS8575 and the dehydrogenase-disrupted S120106. Our findings suggest that components of hemicellulose and pectins affect leaf biomechanical properties and may play an important role in the ability of this model system to survive drought.

  7. Herbivore-induced maize leaf volatiles affect attraction and feeding behaviour of Spodoptera littoralis caterpillars

    Directory of Open Access Journals (Sweden)

    Georg E. von Mérey

    2013-06-01

    Full Text Available Plants under herbivore attack emit volatile organic compounds (VOCs that can serve as foraging cues for natural enemies. Adult females of Lepidoptera, when foraging for host plants to deposit eggs, are commonly repelled by herbivore-induced VOCs, probably to avoid competition and natural enemies. Their larval stages, on the other hand, have been shown to be attracted to inducible VOCs. We speculate that this contradicting behaviour of lepidopteran larvae is due to a need to quickly find a new suitable host plant if they have fallen to the ground. However, once they are on a plant they might avoid the sites with fresh damage to limit competition and risk of cannibalism by conspecifics, as well as exposure to natural enemies. To test this we studied the effect of herbivore-induced VOCs on the attraction of larvae of the moth Spodoptera littoralis and on their feeding behaviour. The experiments further considered the importance of previous feeding experience on the responses of the larvae. It was confirmed that herbivore-induced VOCs emitted by maize plants are attractive to the larvae, but exposure to the volatiles decreased the growth rate of caterpillars at early developmental stages. Larvae that had fed on maize previously were more attracted by VOCs of induced maize than larvae that had fed on artificial diet. At relatively high concentrations synthetic green leaf volatiles, indicative of fresh damage, also negatively affected the growth rate of caterpillars, but not at low concentrations. In all cases, feeding by the later stages of the larvae was not affected by the VOCs. The results are discussed in the context of larval foraging behaviour under natural conditions, where there may be a trade-off between using available host plant signals and avoiding competitors and natural enemies.

  8. Reactive uptake of ozone at simulated leaf surfaces: Implications for 'non-stomatal' ozone flux

    Science.gov (United States)

    Cape, J. Neil; Hamilton, Richard; Heal, Mathew R.

    The reaction of ozone (O 3) with α-pinene has been studied as a function of temperature and relative humidity and in the presence of wax surfaces that simulate a leaf surface. The objective was to determine whether the presence of a wax surface, in which α-pinene could dissolve and form a high surface concentration, would lead to enhanced reaction with O 3. The reaction of O 3 itself with the empty stainless steel reactor and with aluminium and wax surfaces demonstrated an apparent activation energy of around 30 kJ mol -1 for all the surfaces, similar to that observed in long-term field measurements of O 3 fluxes to vegetation. However, the absolute reaction rate was 14 times greater for aluminium foil and saturated hydrocarbon wax surfaces than for stainless steel, and a further 5 times greater for beeswax than hydrocarbon wax. There was no systematic dependence on either relative or absolute humidity for these surface reactions over the range studied (20-100% RH). Reaction of O 3 with α-pinene occurred at rates close to those predicted for the homogeneous gas-phase reaction, and was similar for both the empty reactor and in the presence of wax surfaces. The hypothesis of enhanced reaction at leaf surfaces caused by enhanced surface concentrations of α-pinene was therefore rejected. Comparison of surface decomposition reactions on different surfaces as reported in the literature with the results obtained here demonstrates that the loss of ozone at the earth's surface by decomposition to molecular oxygen (i.e. without oxidative reaction with a substrate) can account for measured 'non-stomatal' deposition velocities of a few mm s -1. In order to quantify such removal, the effective molecular surface area of the vegetation/soil canopy must be known. Such knowledge, combined with the observed temperature-dependence, provides necessary input to global-scale models of O 3 removal from the troposphere at the earth's surface.

  9. How surface damage removal affects fatigue life

    Science.gov (United States)

    Jeelani, S.; Scott, M. A.

    1988-01-01

    The effect of the removal of work hardened surface layers from specimens of 2024-T4 aluminum alloy and AISI-4130 steel on their fatigue lives has been investigated. Specimens were fatigued at selected stress levels for a given number of cycles, and the surface layer was removed followed by subsequent fatigue cycling. Results confirm that when a material is subjected to fatigue loading, damage accumulates in the surface layers in the form of work hardening. Removal of the surface layer brings the specimen back to its pre-fatigued condition.

  10. A method for quantitative analysis of spatially variable physiological processes across leaf surfaces.

    Science.gov (United States)

    Aldea, Mihai; Frank, Thomas D; DeLucia, Evan H

    2006-11-01

    Many physiological processes are spatially variable across leaf surfaces. While maps of photosynthesis, stomatal conductance, gene expression, water transport, and the production of reactive oxygen species (ROS) for individual leaves are readily obtained, analytical methods for quantifying spatial heterogeneity and combining information gathered from the same leaf but with different instruments are not widely used. We present a novel application of tools from the field of geographical imaging to the multivariate analysis of physiological images. Procedures for registration and resampling, cluster analysis, and classification provide a general framework for the analysis of spatially resolved physiological data. Two experiments were conducted to illustrate the utility of this approach. Quantitative analysis of images of chlorophyll fluorescence and the production of ROS following simultaneous exposure of soybean leaves to atmospheric O3 and soybean mosaic virus revealed that areas of the leaf where the operating quantum efficiency of PSII was depressed also experienced an accumulation of ROS. This correlation suggests a causal relationship between oxidative stress and inhibition of photosynthesis. Overlaying maps of leaf surface temperature and chlorophyll fluorescence following a photoinhibition treatment indicated that areas with low operating quantum efficiency of PSII also experienced reduced stomatal conductance (high temperature). While each of these experiments explored the covariance of two processes by overlaying independent images gathered with different instruments, the same procedures can be used to analyze the covariance of information from multiple images. The application of tools from geographic image analysis to physiological processes occurring over small spatial scales will help reveal the mechanisms generating spatial variation across leaves.

  11. Leaf surface factors of transgenic Bt cotton associated with the feeding behaviors of cotton aphids:A case study on non-target effects

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The present paper reports case study results of the risk assessment of transgenic Bt cotton on a non-target pest, cotton aphid, Aphis gossypii. Several types of techniques, i.e., electrical penetration graph (EPG), light and electron microscopy, bioassays and chemical analysis, were applied to investigate physical and chemical leaf factors of 2 transgenic Bt cotton lines (GK12 and GK19) and their pa-rental non-Bt cotton line (Simian3) associated with searching and feeding behaviors of cotton aphids on leaves or leaf extracts of cotton plants. EPG results showed that there were some differences among behaviors of cotton aphids on 2 Bt cotton and 1 non-Bt cotton lines. Cotton aphids performed similarly to leaf surface extracts from 3 cotton lines; and leaf surface chemicals, mainly volatiles and waxes, were almost identical in the components and concentrations among the cotton lines. However, three cotton lines were quite different from each other in the densities of certain kinds of covering trichomes. Therefore, the relationships between the physical characteristics and the searching behaviors of cotton aphids on the three cotton lines were constructed as the regression equations. Glandular trichomes and covering trichomes with 5 branches influenced the cotton aphids’ searching behaviors effectively; and other trichomes with other branches affected aphids in varying ways. These results demonstrated that leaf surface physical factors of transgenic Bt cotton lines different from their parental non-Bt line could affect the penetration behaviors of non-target cotton aphids. Cotton aphids penetrate and feed more easily on two Bt cotton lines than on the non-Bt cotton line.

  12. Leaf surface factors of transgenic Bt cotton associated with the feeding behaviors of cotton aphids: a case study on non-target effects.

    Science.gov (United States)

    Xue, Kun; Deng, Su; Wang, RongJiang; Yan, FengMing; Xu, ChongRen

    2008-02-01

    The present paper reports case study results of the risk assessment of transgenic Bt cotton on a non-target pest, cotton aphid, Aphis gossypii. Several types of techniques, i.e., electrical penetration graph (EPG), light and electron microscopy, bioassays and chemical analysis, were applied to investigate physical and chemical leaf factors of 2 transgenic Bt cotton lines (GK12 and GK19) and their parental non-Bt cotton line (Simian3) associated with searching and feeding behaviors of cotton aphids on leaves or leaf extracts of cotton plants. EPG results showed that there were some differences among behaviors of cotton aphids on 2 Bt cotton and 1 non-Bt cotton lines. Cotton aphids performed similarly to leaf surface extracts from 3 cotton lines; and leaf surface chemicals, mainly volatiles and waxes, were almost identical in the components and concentrations among the cotton lines. However, three cotton lines were quite different from each other in the densities of certain kinds of covering trichomes. Therefore, the relationships between the physical characteristics and the searching behaviors of cotton aphids on the three cotton lines were constructed as the regression equations. Glandular trichomes and covering trichomes with 5 branches influenced the cotton aphids' searching behaviors effectively; and other trichomes with other branches affected aphids in varying ways. These results demonstrated that leaf surface physical factors of transgenic Bt cotton lines different from their parental non-Bt line could affect the penetration behaviors of non-target cotton aphids. Cotton aphids penetrate and feed more easily on two Bt cotton lines than on the non-Bt cotton line.

  13. Leaf surface factors of transgenic Bt cotton associated with the feeding behaviors of cotton aphids: A case study on non-target effects

    Institute of Scientific and Technical Information of China (English)

    XUE Kun; DENG Su; WANG RongJiang; YAN FengMing; XU ChongRen

    2008-01-01

    The present paper reports case study results of the risk assessment of transgenic Bt cotton on a non-target pest, cotton aphid, Aphis gossypii. Several types of techniques, i.e., electrical penetration graph (EPG), light and electron microscopy, bioessays and chemical analysis, were applied to investigate physical and chemical leaf factors of 2 transgenic Bt cotton lines(GK12 and GK19) and their parental non-Bt cotton line (Simian3) associated with searching and feeding behaviors of cotton aphids on leaves or leaf extracts of cotton plants. EPG results showed that there were some differences among behaviors of cotton aphids on 2 Bt cotton and 1 non-Bt cotton lines. Cotton aphids performed similarly to leaf surface extracts from 3 cotton lines; and leaf surface chemicals, mainly volatiles and waxes,were almost identical in the components and concentrations among the cotton lines. However, three cotton lines were quite different from each other in the densities of certain kinds of covering trichomes.Therefore, the relationships between the physical characteristics and the searching behaviors of cotton aphids on the three cotton lines were constructed as the regression equations. Glandular trichomes and covering trichomes with 5 branches Influenced the cotton aphids' searching behaviors effectively;and other trichomes with other branches affected aphids in varying ways. These results demonstrated that leaf surface physical factors of transgenic Bt cotton lines different from their parental non-Bt line could affect the penetration behaviors of non-target cotton aphids. Cotton aphids penetrate and feed more easily on two Bt cotton lines than on the non-Bt cotton line.

  14. Preparation of Material Surface Structure Similar to Hydrophobic Structure of Lotus Leaf

    Institute of Scientific and Technical Information of China (English)

    CAO Feng; GUAN Zisheng; LI Dongxu

    2008-01-01

    Nano/micro replication,a technique widely applied in the microelectronics field,was introduced to prepare the hydrophobic bionics microstructure on material surface.Poly(vinyl alcohol)(PVA)and polystyrene(PS)moulds of the mastoid microstructure on lotus leaf surface were prepared respectively by the nano/micro replication technology.And poly(dimethylsiloxane)(PDMS)replicas with the mastoid-like microstructure were prepared from these two kinds of polymer moulds.Scanning electronic microscope(SEM) was employed to investigate the morphology and microstructures on moulds and replicas.Both the static and dynamic contact angles between water droplet and PDMS replicas'surface were also measured.As a result,similar microstructure Can be observed clearly on the surface of PDMS replicas and the static contact angle on PDMS replicas was enhanced dramatically by the existence of these microstructures.

  15. Leaf physiological processes strongly affect δH2 values of leaf wax n-alkanes in C3 and C4 grasses.

    Science.gov (United States)

    Gamarra, Bruno; Sachse, Dirk; Kahmen, Ansgar

    2013-04-01

    Leaf wax n-alkanes are naturally synthesized saturated hydrocarbons. They are synthesized as part of plant leaf cuticle as a mechanism to prevent water losses. Two of the most important features of n-alkanes are their enormous environmental persistence and terrestrial ubiquity making them a solid and reliable long-term and large-scale biomarker. Their hydrogen isotopic composition (δH2) of leaf wax n-alkanes has been traditionally related to precipitation. Leaf wax n-alkanes and their δH2 values have thus been celebrated as biomarkers to reconstruct hydrological changes. δH2 values of leaf wax n-alkanes are yet to be fully comprehended. They are basically determined by three mechanisms: (1) The δH2 value of the plant source water (2) leaf water evaporative enrichment in H2 and (3) biosynthetic fractionation and depletion in H2during their biosynthesis from leaf water. Out of these three, the exact degree by which the evaporative H2-enrichment of leaf water influences the δH2 values of leaf wax n-alkanes is still unknown. We conducted an experiment where we tested and quantified the effects of leaf water evaporative H2-enrichment on the leaf wax n-alkane δH2 values of different grass species. We grew 12 C3 and C4 grass species under controlled environmental conditions in growth chambers. The plants were exposed to 3 different levels of air relative humidity (45, 65 and 85%). These treatments were to generate different degrees of leaf water H2-enrichment in the plants. The goal of our experiment was to determine by what degree the different levels of leaf water H2-enrichment influence the δH2 values of the different C3 and C4 grass species. Additional measurements of gas exchange, evapotranspiration and leaf length and area accompanied the isotopic analysis in order to explain species variability. Our experiments showed that leaf water evaporative H2-enrichment has a critical impact on leaf wax n-alkane δH2 values of all studied plants. The magnitude was

  16. The effect of leaf litter cover on surface runoff and soil erosion in Northern China.

    Directory of Open Access Journals (Sweden)

    Xiang Li

    Full Text Available The role of leaf litter in hydrological processes and soil erosion of forest ecosystems is poorly understood. A field experiment was conducted under simulated rainfall in runoff plots with a slope of 10%. Two common types of litter in North China (from Quercus variabilis, representing broadleaf litter, and Pinus tabulaeformis, representing needle leaf litter, four amounts of litter, and five rainfall intensities were tested. Results revealed that the litter reduced runoff and delayed the beginning of runoff, but significantly reduced soil loss (p<0.05. Average runoff yield was 29.5% and 31.3% less than bare-soil plot, and for Q. variabilis and P. tabulaeformis, respectively, and average sediment yield was 85.1% and 79.9% lower. Rainfall intensity significantly affected runoff (R = 0.99, p<0.05, and the efficiency in runoff reduction by litter decreased considerably. Runoff yield and the runoff coefficient increased dramatically by 72.9 and 5.4 times, respectively. The period of time before runoff appeared decreased approximately 96.7% when rainfall intensity increased from 5.7 to 75.6 mm h-1. Broadleaf and needle leaf litter showed similarly relevant effects on runoff and soil erosion control, since no significant differences (p≤0.05 were observed in runoff and sediment variables between two litter-covered plots. In contrast, litter mass was probably not a main factor in determining runoff and sediment because a significant correlation was found only with sediment in Q. variabilis litter plot. Finally, runoff yield was significantly correlated (p<0.05 with sediment yield. These results suggest that the protective role of leaf litter in runoff and erosion processes was crucial, and both rainfall intensity and litter characteristics had an impact on these processes.

  17. Antioxidant Capacity and Phenolic Content in Olive Leaf Tisane as Affected by Boiling Treatment

    Directory of Open Access Journals (Sweden)

    Fathia AOUIDI

    2016-06-01

    Full Text Available This paper investigated the effect of preparation method on the quality of olive leaf tisane. Secondly, it aimed at evaluating and understanding the effect of boiling treatment on phenolic compounds and antioxidant capacity of an aqueous extract of olive leaves. The Phenolic content was determined by Folin-Ciocalteu method. The antioxidant capacity was assessed by ABTS+ method. The Phenolic content and antioxidant capacity depended on extraction procedure of olive leaf tisane. It was found that boiling leads to a decrease in the phenolic content and a rise of antioxidant capacity of aqueous extract from olive leaves. The mass molecular distribution of the polymeric aromatic fraction was analyzed by gel filtration chromatography on Sephadex G50. Results suggested the hydrolysis of phenolic polymers following boiling. Moreover, HPLC analyses showed an increase in rutin, oleuropein and caffeic acid levels in treated sample. As a conclusion, thermal processing could be useful for enhancing the antioxidant capacity and the extractability of phenolic compounds in olive leaf tisane.

  18. Leaf surface lipophilic compounds as one of the factors of silver birch chemical defense against larvae of gypsy moth.

    Directory of Open Access Journals (Sweden)

    Vyacheslav V Martemyanov

    Full Text Available Plant chemical defense against herbivores is a complex process which involves a number of secondary compounds. It is known that the concentration of leaf surface lipophilic compounds (SLCs, particularly those of flavonoid aglycones are increased with the defoliation treatment of silver birch Betula pendula. In this study we investigated how the alteration of SLCs concentration in the food affects the fitness and innate immunity of the gypsy moth Lymantria dispar. We found that a low SLCs concentrations in consumed leaves led to a rapid larval development and increased females' pupae weight (= fecundity compared to larvae fed with leaves with high SLCs content. Inversely, increasing the compounds concentration in an artificial diet produced the reverse effects: decreases in both larval weight and larval survival. Low SLCs concentrations in tree leaves differently affected larval innate immunity parameters. For both sexes, total hemocytes count in the hemolymph increased, while the activity of plasma phenoloxidase decreased when larvae consume leaves with reduced content of SLCs. Our results clearly demonstrate that the concentration of SLCs in silver birch leaves affects not only gypsy moth fitness but also their innate immune status which might alter the potential resistance of insects against infections and/or parasitoids.

  19. Evolution and environmental degradation of superhydrophobic aspen and black locust leaf surfaces

    Science.gov (United States)

    Tranquada, George Christopher

    The current study is focused on the characterization of four natural leaf species (quaking, bigtooth and columnar european aspen as well as black locust) possessing a unique dual-scale cuticle structure composed of micro- and nano-scale asperities, which are able to effectively resist wetting (superhydrophobic), characteristic of The Lotus Effect. Scanning Electron Microscopy (SEM) was used to track the growth and evolution of their distinctive nano-scale epicuticular wax (ECW) morphologies over one full growing season. In addition, the stability of their superhydrophobic property was tested in various environments. It was determined that the long-term stability of these surfaces is tentatively linked to various environmental stress factors. Specifically, a combination of high temperature and humidity caused the degradation of nanoscale asperities and loss of the superhydrophobic property. The dual-scale surface structure was found to provide a suitable template for the design of future superhydrophobic engineering materials.

  20. The effect of leaf litter cover on surface runoff and soil erosion in Northern China.

    Science.gov (United States)

    Li, Xiang; Niu, Jianzhi; Xie, Baoyuan

    2014-01-01

    The role of leaf litter in hydrological processes and soil erosion of forest ecosystems is poorly understood. A field experiment was conducted under simulated rainfall in runoff plots with a slope of 10%. Two common types of litter in North China (from Quercus variabilis, representing broadleaf litter, and Pinus tabulaeformis, representing needle leaf litter), four amounts of litter, and five rainfall intensities were tested. Results revealed that the litter reduced runoff and delayed the beginning of runoff, but significantly reduced soil loss (psoil plot, and for Q. variabilis and P. tabulaeformis, respectively, and average sediment yield was 85.1% and 79.9% lower. Rainfall intensity significantly affected runoff (R = 0.99, psoil erosion control, since no significant differences (p≤0.05) were observed in runoff and sediment variables between two litter-covered plots. In contrast, litter mass was probably not a main factor in determining runoff and sediment because a significant correlation was found only with sediment in Q. variabilis litter plot. Finally, runoff yield was significantly correlated (perosion processes was crucial, and both rainfall intensity and litter characteristics had an impact on these processes.

  1. Leaf surface wax is a source of plant methane formation under UV radiation and in the presence of oxygen

    DEFF Research Database (Denmark)

    Bruhn, Dan; Mikkelsen, Teis Nørgaard; Rolsted, M. M. M.

    2014-01-01

    to this, we demonstrated that the UV radiation-induced CH4 emission is independent of leaf area index above unity. Further, we observed that the presence of O2 in the atmosphere was necessary for achieving the highest rates of CH4 emission. Methane formation from leaf surface wax is supposedly a two......The terrestrial vegetation is a source of UV radiation-induced aerobic methane (CH4) release to the atmosphere. Hitherto pectin, a plant structural component, has been considered as the most likely precursor for this CH4 release. However, most of the leaf pectin is situated below the surface wax...... layer, and UV transmittance of the cuticle differs among plant species. In some species, the cuticle effectively absorbs and/or reflects UV radiation. Thus, pectin may not necessarily contribute substantially to the UV radiation-induced CH4 emission measured at surface level in all species. Here, we...

  2. Optimization of olive leaf extract obtained by ultrasound-assisted extraction with response surface methodology.

    Science.gov (United States)

    Şahin, Selin; Samlı, Rüya

    2013-01-01

    In the present article, ultrasound-assisted extraction (UAE) of polyphenols from agricultural and industrial waste of olive oil and table oil productions, olive tree (Olea europaea) leaves were investigated. The aim of the study is to examine the extraction parameters such as solvent concentration (0-100% ethanol (EtOH), v/v), the ratio of solid to solvent (25-50mg/mL) and extraction time (20-60 min), and to obtain the best possible combinations of these parameters through response surface methodology (RSM). The extract yield was stated as mg extract per g of dried leaf (DL). Total phenolic content was expressed in gallic acid equivalent (GAE) per g of dried leaf. Free radical scavenging activity for the antioxidant capacity was tested by 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical. The second order polynomial model gave a satisfactory description of the experimental data. 201.2158 mg extract/g DL, 25.0626 mg GAE/g DL, and 95.5610% in respect to inhibition of DPPH radical were predicted at the optimum operating conditions (500 mg solid to 10 mL solvent ratio, 60 min of extraction time and 50% EtOH composition), respectively.

  3. Oleuropein-Enriched Olive Leaf Extract Affects Calcium Dynamics and Impairs Viability of Malignant Mesothelioma Cells

    Directory of Open Access Journals (Sweden)

    Carla Marchetti

    2015-01-01

    Full Text Available Malignant mesothelioma is a poor prognosis cancer in urgent need of alternative therapies. Oleuropein, the major phenolic of olive tree (Olea europaea L., is believed to have therapeutic potentials for various diseases, including tumors. We obtained an oleuropein-enriched fraction, consisting of 60% w/w oleuropein, from olive leaves, and assessed its effects on intracellular Ca2+ and cell viability in mesothelioma cells. Effects of the oleuropein-enriched fraction on Ca2+ dynamics and cell viability were studied in the REN mesothelioma cell line, using fura-2 microspectrofluorimetry and MTT assay, respectively. Fura-2-loaded cells, transiently exposed to the oleuropein-enriched fraction, showed dose-dependent transient elevations of cytosolic Ca2+ concentration (Ca2+i. Application of standard oleuropein and hydroxytyrosol, and of the inhibitor of low-voltage T-type Ca2+ channels NNC-55-0396, suggested that the effect is mainly due to oleuropein acting through its hydroxytyrosol moiety on T-type Ca2+ channels. The oleuropein-enriched fraction and standard oleuropein displayed a significant antiproliferative effect, as measured on REN cells by MTT cell viability assay, with IC50 of 22 μg/mL oleuropein. Data suggest that our oleuropein-enriched fraction from olive leaf extract could have pharmacological application in malignant mesothelioma anticancer therapy, possibly by targeting T-type Ca2+ channels and thereby dysregulating intracellular Ca2+ dynamics.

  4. The bacterial pathogen Xylella fastidiosa affects the leaf ionome of plant hosts during infection.

    Directory of Open Access Journals (Sweden)

    Leonardo De La Fuente

    Full Text Available Xylella fastidiosa is a plant pathogenic bacterium that lives inside the host xylem vessels, where it forms biofilm believed to be responsible for disrupting the passage of water and nutrients. Here, Nicotiana tabacum was infected with X. fastidiosa, and the spatial and temporal changes in the whole-leaf ionome (i.e. the mineral and trace element composition were measured as the host plant transitioned from healthy to diseased physiological status. The elemental composition of leaves was used as an indicator of the physiological changes in the host at a specific time and relative position during plant development. Bacterial infection was found to cause significant increases in concentrations of calcium prior to the appearance of symptoms and decreases in concentrations of phosphorous after symptoms appeared. Field-collected leaves from multiple varieties of grape, blueberry, and pecan plants grown in different locations over a four-year period in the Southeastern US showed the same alterations in Ca and P. This descriptive ionomics approach characterizes the existence of a mineral element-based response to X. fastidiosa using a model system suitable for further manipulation to uncover additional details of the role of mineral elements during plant-pathogen interactions. This is the first report on the dynamics of changes in the ionome of the host plant throughout the process of infection by a pathogen.

  5. Hierarchical porous carbon with ultrahigh surface area from corn leaf for high-performance supercapacitors application

    Science.gov (United States)

    Yang, Xiaoqing; Li, Chengfei; Chen, Yue

    2017-02-01

    A new class of hierarchical porous carbon (HPC) with ultrahigh surface area is successfully fabricated by carefully selecting biomass carbon precursors and activation reagent, through which corn leaf (CL) with natural well-defined macropore channels is used as the carbon precursor, and H3PO4 is used as the active agent by virtue of its pore-widening effect. The as-prepared CL-based HPC (CLHPC) with a H3PO4/semi-carbonized CL mass ratio of 2 (CLHPC-2) demonstrates the highest specific surface area of 2507 m2 g-1 donated by 28.3% of micropore and 71.6% of mesopore, while maintaining the channel-like macroporous structure derived from the well-defined natural structure in CL. The combination of the hierarchical porous structure and ultrahigh surface area enables rapid electrolyte diffusion and sufficient active sites for charge accumulation. As a result, CLHPC-2 exhibits excellent electrochemical performance, such as high specific capacitance of 230 F g-1 at the current density of 0.1 A g-1, excellent high-rate capability (retention of 91% from 0.1 to 5 A g-1), and good cycling stability (99% capacitance retention after 10 000 cycles).

  6. 稻叶表面特性及雾滴在倾角稻叶上的沉积行为%Characteristics of Rice Leaf Surface and Droplets Deposition Behavior on Rice Leaf Surface with Different Inclination Angles

    Institute of Scientific and Technical Information of China (English)

    徐广春; 顾中言; 徐德进; 许小龙

    2014-01-01

    θr)的分析结果表明θa总是大于θr,在40 s的测定时间内,随时间延迟θa和θr总是逐渐减少。结论稻叶的强疏水性主要归因于其表面布满了包被着蜡质的乳头状突起,同时这还可能与其叶表面的毛长和气孔密度密切相关。水稻叶面为低能叶面。只有Silwet-408溶液的表面张力小于稻叶的临界表面张力且溶液中的Silwet-408浓度达到临界胶束浓度才能使雾滴很好的黏附在不同倾角的稻叶上并润湿展布;过低浓度的溶液的雾滴由于较大的表面张力易从不同倾角的稻叶上滚落。Silwet-408溶液的雾滴在不同倾角叶片上的θa大于θr形成的润湿滞后说明了稻叶表面的粗糙,而这种粗糙与稻叶表面存在的高密度乳突密切相关。%Objective]In order to provide a basis of mechanisms controlling retention of pesticide droplets on target leaf, characterization of rice leaf surface and behavior analysis of single droplets of trisiloxane surfactant (Silwet-408) solutions on rice leaf surface with different inclination angles were studied.[Method]Scanning electron microscope (SEM) was used for observation of rice leaf surface characteristics and the critical surface tension (CST) of rice leaf was determined by Zisman method. Surface tension of Silwet-408 solutions at concentrations of 0, 3.91, 7.81, 15.63, 31.25, 62.50, 125.00 and 250.00 mg·L-1 was measured and the critical micelle concentration (CMC) of Silwet-408 was also measured according to the change of surface tension of Silwet-408 solutions. Then the contact angle of a single droplet on the rice leaf surface with 3 inclination angles was determined by contact angle meter.[Result]SEM images showed that 3 types of hairs and densely covered papillae were observed on both the adaxial and abaxial sides of rice leaf. Densities of papillae, with significant difference between the adaxial and abaxial rice leaf surface, were ((12.4±0.7)×103) and ((7.6±0.8)

  7. Heat-induced electrical signals affect cytoplasmic and apoplastic pH as well as photosynthesis during propagation through the maize leaf.

    Science.gov (United States)

    Grams, Thorsten E E; Lautner, Silke; Felle, Hubert H; Matyssek, Rainer; Fromm, Jörg

    2009-04-01

    Combining measurements of electric potential and pH with such of chlorophyll fluorescence and leaf gas exchange showed heat stimulation to evoke an electrical signal (propagation speed: 3-5 mm s(-1)) that travelled through the leaf while reducing the net CO(2) uptake rate and the photochemical quantum yield of both photosystems (PS). Two-dimensional imaging analysis of the chlorophyll fluorescence signal of PS II revealed that the yield reduction spread basipetally via the veins through the leaf at a speed of 1.6 +/- 0.3 mm s(-1) while the propagation speed in the intervein region was c. 50 times slower. Propagation of the signal through the veins was confirmed because PS I, which is present in the bundle sheath cells around the leaf vessels, was affected first. Hence, spreading of the signal along the veins represents a path with higher travelling speed than within the intervein region of the leaf lamina. Upon the electrical signal, cytoplasmic pH decreased transiently from 7.0 to 6.4, while apoplastic pH increased transiently from 4.5 to 5.2. Moreover, photochemical quantum yield of isolated chloroplasts was strongly affected by pH changes in the surrounding medium, indicating a putative direct influence of electrical signalling via changes of cytosolic pH on leaf photosynthesis.

  8. Tree Species Composition and Harvest Intensity Affect Herbivore Density and Leaf Damage on Beech, Fagus sylvatica, in Different Landscape Contexts.

    Science.gov (United States)

    Mangels, Jule; Blüthgen, Nico; Frank, Kevin; Grassein, Fabrice; Hilpert, Andrea; Mody, Karsten

    2015-01-01

    Most forests are exposed to anthropogenic management activities that affect tree species composition and natural ecosystem processes. Changes in ecosystem processes such as herbivory depend on management intensity, and on regional environmental conditions and species pools. Whereas influences of specific forest management measures have already been addressed for different herbivore taxa on a local scale, studies considering effects of different aspects of forest management across different regions are rare. We assessed the influence of tree species composition and intensity of harvesting activities on arthropod herbivores and herbivore-related damage to beech trees, Fagus sylvatica, in 48 forest plots in three regions of Germany. We found that herbivore abundance and damage to beech trees differed between regions and that - despite the regional differences - density of tree-associated arthropod taxa and herbivore damage were consistently affected by tree species composition and harvest intensity. Specifically, overall herbivore damage to beech trees increased with increasing dominance of beech trees - suggesting the action of associational resistance processes - and decreased with harvest intensity. The density of leaf chewers and mines was positively related to leaf damage, and several arthropod groups responded to beech dominance and harvest intensity. The distribution of damage patterns was consistent with a vertical shift of herbivores to higher crown layers during the season and with higher beech dominance. By linking quantitative data on arthropod herbivore abundance and herbivory with tree species composition and harvesting activity in a wide variety of beech forests, our study helps to better understand the influence of forest management on interactions between a naturally dominant deciduous forest tree and arthropod herbivores.

  9. Tree Species Composition and Harvest Intensity Affect Herbivore Density and Leaf Damage on Beech, Fagus sylvatica, in Different Landscape Contexts.

    Directory of Open Access Journals (Sweden)

    Jule Mangels

    Full Text Available Most forests are exposed to anthropogenic management activities that affect tree species composition and natural ecosystem processes. Changes in ecosystem processes such as herbivory depend on management intensity, and on regional environmental conditions and species pools. Whereas influences of specific forest management measures have already been addressed for different herbivore taxa on a local scale, studies considering effects of different aspects of forest management across different regions are rare. We assessed the influence of tree species composition and intensity of harvesting activities on arthropod herbivores and herbivore-related damage to beech trees, Fagus sylvatica, in 48 forest plots in three regions of Germany. We found that herbivore abundance and damage to beech trees differed between regions and that - despite the regional differences - density of tree-associated arthropod taxa and herbivore damage were consistently affected by tree species composition and harvest intensity. Specifically, overall herbivore damage to beech trees increased with increasing dominance of beech trees - suggesting the action of associational resistance processes - and decreased with harvest intensity. The density of leaf chewers and mines was positively related to leaf damage, and several arthropod groups responded to beech dominance and harvest intensity. The distribution of damage patterns was consistent with a vertical shift of herbivores to higher crown layers during the season and with higher beech dominance. By linking quantitative data on arthropod herbivore abundance and herbivory with tree species composition and harvesting activity in a wide variety of beech forests, our study helps to better understand the influence of forest management on interactions between a naturally dominant deciduous forest tree and arthropod herbivores.

  10. Metals Accumulation and Leaf Surface Anatomy of Murdannia spectabilis Growing in Zn/Cd Contaminated Soil

    Directory of Open Access Journals (Sweden)

    Ladawan Rattanapolsan

    2013-07-01

    Full Text Available Murdannia spectabilis (Kurz Faden was identified as a Zn/Cd hyperaccumulative plant. Leaf surface anatomy of the plant growing in non-contaminated soil (control and Zn/Cd contaminated soil,was studied and compared by a light microscopy and scanning electron microscopy combined with Energy-dispersive X-ray spectroscopy(SEM/EDS. The similarities were reticulate cuticle on epidermises, uniform polygonal cell, stomatal arrangement in six surrounding subsidiary cells, and submarginal sclerenchyma. The dissimilarities were uniserate trichomes spreading on both adaxial and abaxial epidermis of the plants growing in non-contaminated soil, whereas the uniserate trichomes were only on the submarginal-adaxial epidermis of the control plants. The trichomes on leaves of the plants growing in non-contaminated soil were found to have both uniseriate non-glandular and uniseriate glandular trichomes;whereas, leaves of the plants growing in the contaminated soil were merely non-glandular trichomes. The different shape and location of trichomes, the number of stomata and trichome indicated the effect of Zn and Cd on M. spectabilis. The higher percentages of Zn and Cd in the vascular bundle than in the cross section and epidermis areas showed both solutes could move along each route, with diffusion through the symplast and apoplast. The increase of Ca in M. spectabilis growing in Zn/Cd contaminated soil corresponded to the Zn and Cd distributed in the leaves. Zn K-edge and S K-edge XANES spectra proposed that Zn2+ ions were accumulated and/or adsorbed on the epidermis of the tuber, and then absorbed into the root and transport to the xylem. The double peaks of Zn-cysteine in the leaf samples proposed the metal sequestration was by sulphur proteins.

  11. 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.

  12. AtLSG1-2 Regulates Leaf Growth by Affecting Cell Proliferation and the Onset of Endoreduplication and Synergistically Interacts with AtNMD3 during Cell Proliferation Process

    KAUST Repository

    Zhao, Huayan

    2017-03-10

    AtLSG1-2 is a circularly permuted GTPase required for ribosome biogenesis and recently shown to be involved in early leaf development, although it was unclear how AtLSG1-2 affects leaf growth. Here, we found that atlsg1-2 mutants had reduced leaf size as a result of decreased cell size and cell number. Leaf kinematic analysis and CYCB1;1

  13. Antiphase light and temperature cycles affect PHYTOCHROME B-controlled ethylene sensitivity and biosynthesis, limiting leaf movement and growth of Arabidopsis.

    Science.gov (United States)

    Bours, Ralph; van Zanten, Martijn; Pierik, Ronald; Bouwmeester, Harro; van der Krol, Alexander

    2013-10-01

    In the natural environment, days are generally warmer than the night, resulting in a positive day/night temperature difference (+DIF). Plants have adapted to these conditions, and when exposed to antiphase light and temperature cycles (cold photoperiod/warm night [-DIF]), most species exhibit reduced elongation growth. To study the physiological mechanism of how light and temperature cycles affect plant growth, we used infrared imaging to dissect growth dynamics under +DIF and -DIF in the model plant Arabidopsis (Arabidopsis thaliana). We found that -DIF altered leaf growth patterns, decreasing the amplitude and delaying the phase of leaf movement. Ethylene application restored leaf growth in -DIF conditions, and constitutive ethylene signaling mutants maintain robust leaf movement amplitudes under -DIF, indicating that ethylene signaling becomes limiting under these conditions. In response to -DIF, the phase of ethylene emission advanced 2 h, but total ethylene emission was not reduced. However, expression analysis on members of the 1-aminocyclopropane-1-carboxylic acid (ACC) synthase ethylene biosynthesis gene family showed that ACS2 activity is specifically suppressed in the petiole region under -DIF conditions. Indeed, petioles of plants under -DIF had reduced ACC content, and application of ACC to the petiole restored leaf growth patterns. Moreover, acs2 mutants displayed reduced leaf movement under +DIF, similar to wild-type plants under -DIF. In addition, we demonstrate that the photoreceptor PHYTOCHROME B restricts ethylene biosynthesis and constrains the -DIF-induced phase shift in rhythmic growth. Our findings provide a mechanistic insight into how fluctuating temperature cycles regulate plant growth.

  14. Enhanced monsoon precipitation and nitrogen deposition affect leaf traits and photosynthesis differently in spring and summer in the desert shrub Larrea tridentata.

    Science.gov (United States)

    Barker, D H; Vanier, C; Naumburg, E; Charlet, T N; Nielsen, K M; Newingham, B A; Smith, S D

    2006-01-01

    Leaf-level CO2 assimilation (A(area)) can largely be predicted from stomatal conductance (g(s)), leaf morphology (SLA) and nitrogen (N) content (N(area)) in species across biomes and functional groups. The effects of simulated global change scenarios, increased summer monsoon rain (+H2O), N deposition (+N) and the combination (+H2O +N), were hypothesized to affect leaf trait-photosynthesis relationships differently in the short- and long-term for the desert shrub Larrea tridentata. During the spring, +H2O and +H2O +N plants had lower A(area) and g(s), but similar shoot water potential (Psi(shoot)) compared with control and +N plants; differences in A(area) were attributed to lower leaf N(area) and g(s). During the summer, +H2O and +H2O +N plants displayed higher A(area) than control and +N plants, which was attributed to higher Psi(shoot), g(s) and SLA. Throughout the year, A(area) was strongly correlated with g(s) but weakly correlated with leaf N(area) and SLA. We concluded that increased summer monsoon had a stronger effect on the performance of Larrea than increased N deposition. In the short term, the +H2O and +H2O +N treatments were associated with increasing A(area) in summer, but also with low leaf N(area) and lower A(area) in the long term the following spring.

  15. Micromorphological features of pollen grains, seeds and leaf surfaces of Atocion hypanicum (Klok. Tzvel. and A. compactum (Fisch. Tzvel.

    Directory of Open Access Journals (Sweden)

    V.O. Martynyuk

    2015-05-01

    Full Text Available Based on scanning electron microscopy, ultrastructure of leaf surfaces, pollen grains and seeds have been investigated for two Atocion Adans. species – Ukrainian endemic A. hypanicum (Klok. Tzvel., and A. compactum (Fisch. Tzvel., which areal comprises the Balkans, Caucasus and Western Asia. New delimiting micromorphological characteristics, associated with ultrastracture of pollen grains (microechinate number on the operculum: A. hypanicum – 6-15, A. compactum – 11-26 and interporal distance (A. hypanicum – 6.72±1,2 μm, A. compactum – 5.19±1,22 μm, have been designated. A. compactum seeds also clearly differ from A. hypanicum by the papilla presence on periclinal walls of lateral and dorsal surfaces. However, ultrastructure of the leaf surface, including epicuticular wax projections, does not significantly differ between these taxa.

  16. Response of sunflower (Helianthus annuus L.) leaf surface defenses to exogenous methyl jasmonate.

    Science.gov (United States)

    Rowe, Heather C; Ro, Dae-kyun; Rieseberg, Loren H

    2012-01-01

    Helianthus annuus, the common sunflower, produces a complex array of secondary compounds that are secreted into glandular trichomes, specialized structures found on leaf surfaces and anther appendages of flowers. The primary components of these trichome secretions are sesquiterpene lactones (STL), a diverse class of compounds produced abundantly by the plant family Compositae and believed to contribute to plant defense against herbivory. We treated wild and cultivated H. annuus accessions with exogenous methyl jasmonate, a plant hormone that mediates plant defense against insect herbivores and certain classes of fungal pathogens. The wild sunflower produced a higher density of glandular trichomes on its leaves than the cultivar. Comparison of the profiles of glandular trichome extracts obtained by liquid chromatography-mass spectroscopy (LC-MS) showed that wild and cultivated H. annuus were qualitatively similar in surface chemistry, although differing in the relative size and proportion of various compounds detected. Despite observing consistent transcriptional responses to methyl jasmonate treatment, we detected no significant effect on glandular trichome density or LC-MS profile in cultivated or wild sunflower, with wild sunflower exhibiting a declining trend in overall STL production and foliar glandular trichome density of jasmonate-treated plants. These results suggest that glandular trichomes and associated compounds may act as constitutive defenses or require greater levels of stimulus for induction than the observed transcriptional responses to exogenous jasmonate. Reduced defense investment in domesticated lines is consistent with predicted tradeoffs caused by selection for increased yield; future research will focus on the development of genetic resources to explicitly test the ecological roles of glandular trichomes and associated effects on plant growth and fitness.

  17. Response of sunflower (Helianthus annuus L. leaf surface defenses to exogenous methyl jasmonate.

    Directory of Open Access Journals (Sweden)

    Heather C Rowe

    Full Text Available Helianthus annuus, the common sunflower, produces a complex array of secondary compounds that are secreted into glandular trichomes, specialized structures found on leaf surfaces and anther appendages of flowers. The primary components of these trichome secretions are sesquiterpene lactones (STL, a diverse class of compounds produced abundantly by the plant family Compositae and believed to contribute to plant defense against herbivory. We treated wild and cultivated H. annuus accessions with exogenous methyl jasmonate, a plant hormone that mediates plant defense against insect herbivores and certain classes of fungal pathogens. The wild sunflower produced a higher density of glandular trichomes on its leaves than the cultivar. Comparison of the profiles of glandular trichome extracts obtained by liquid chromatography-mass spectroscopy (LC-MS showed that wild and cultivated H. annuus were qualitatively similar in surface chemistry, although differing in the relative size and proportion of various compounds detected. Despite observing consistent transcriptional responses to methyl jasmonate treatment, we detected no significant effect on glandular trichome density or LC-MS profile in cultivated or wild sunflower, with wild sunflower exhibiting a declining trend in overall STL production and foliar glandular trichome density of jasmonate-treated plants. These results suggest that glandular trichomes and associated compounds may act as constitutive defenses or require greater levels of stimulus for induction than the observed transcriptional responses to exogenous jasmonate. Reduced defense investment in domesticated lines is consistent with predicted tradeoffs caused by selection for increased yield; future research will focus on the development of genetic resources to explicitly test the ecological roles of glandular trichomes and associated effects on plant growth and fitness.

  18. Water, Nitrogen and Plant Density Affect the Response of Leaf Appearance of Direct Seeded Rice to Thermal Time

    Institute of Scientific and Technical Information of China (English)

    Maite MART(I)NEZ-EIXARCH; ZHU De-feng; Maria del Mar CATAL(A)-FORNER; Eva PLA-MAYOR; Nuria TOM(A)S-NAVARRO

    2013-01-01

    Field experiments were conducted in the Ebro Delta area (Spain),from 2007 to 2009 with two rice varieties:Gleva and Tebre.The experimental treatments included a series of seed rates,two different water management systems and two different nitrogen fertilization times.The number of leaves on the main stems and their emergence time were periodically tagged.The results indicated that the final leaf number on the main stems in the two rice varieties was quite stable over a three-year period despite of the differences in their respective growth cycles.Interaction between nitrogen fertilization and water management influenced the final leaf number on the main stems.Plant density also had a significant influence on the rate of leaf appearance by extending the phyllochron and postponing the onset of intraspecific competition after the emergence of the 7th leaf on the main stems.Final leaf number on the main stems was negatively related to plant density.A relationship between leaf appearance and thermal time was established with a strong nonlinear function.In direct-seeded rice,the length of the phyllochron increases exponentially in line with the advance of plant development.A general model,derived from 2-year experimental data,was developed and satisfactorily validated; it had a root mean square error of 0.3 leaf.An exponential model can be used to predict leaf emergence in direct-seeded rice.

  19. Zinc oxide nanoparticles affect carbon and nitrogen mineralization of Phoenix dactylifera leaf litter in a sandy soil.

    Science.gov (United States)

    Rashid, Muhammad Imtiaz; Shahzad, Tanvir; Shahid, Muhammad; Ismail, Iqbal M I; Shah, Ghulam Mustafa; Almeelbi, Talal

    2017-02-15

    We investigated the impact of zinc oxide nanoparticles (ZnO NPs; 1000mgkg(-1) soil) on soil microbes and their associated soil functions such as date palm (Phoenix dactylifera) leaf litter (5gkg(-1) soil) carbon and nitrogen mineralization in mesocosms containing sandy soil. Nanoparticles application in litter-amended soil significantly decreased the cultivable heterotrophic bacterial and fungal colony forming units (cfu) compared to only litter-amended soil. The decrease in cfu could be related to lower microbial biomass carbon in nanoparticles-litter amended soil. Likewise, ZnO NPs also reduced CO2 emission by 10% in aforementioned treatment but this was higher than control (soil only). Labile Zn was only detected in the microbial biomass of nanoparticles-litter applied soil indicating that microorganisms consumed this element from freely available nutrients in the soil. In this treatment, dissolved organic carbon and mineral nitrogen were 25 and 34% lower respectively compared to litter-amended soil. Such toxic effects of nanoparticles on litter decomposition resulted in 130 and 122% lower carbon and nitrogen mineralization efficiency respectively. Hence, our results entail that ZnO NPs are toxic to soil microbes and affect their function i.e., carbon and nitrogen mineralization of applied litter thus confirming their toxicity to microbial associated soil functions.

  20. Natural enemies of Atta vollenweideri (Hymenoptera: Formicidae) leaf-cutter ants negatively affected by synthetic pesticides, chlorpyrifos and fipronil.

    Science.gov (United States)

    Guillade, Andrea C; Folgarait, Patricia J

    2014-02-01

    In southern South America, Ada vollenweideri Forel (Hymenoptera: Formicidae) is a significant pest of several crops and forestry, also considered to reduce the carrying capacity of pastures. The most usual control method used in Latin America is the application of synthetic pesticides, mainly chlorpyrifos and fipronil. However, no studies have assessed the effects of these agrochemicals on natural enemies of ants. We aimed to evaluate the efficiency of these pesticides on leaf-cutter ants' control and to test their effect on phorid fly parasitoids. Chlorpyrifos failed to exert complete control over ant colonies in the field and was gravely detrimental to specific parasitoids, reducing their percentage of parasitism, pupal survivorship, and adult longevity. Fipronil, however, exerted complete control over the treated colonies. Laboratory tests using both pesticides, either on ants from foraging trails or on pupariae, showed that chlorpyrifos and fipronil decreased larval and pupal survivorship, as well as adult longevity of parasitoids, in comparison to controls. In conclusion, these pesticides will likely affect parasitoids with regard to their reproductive capacity, leading to the decreased levels of natural parasitism observed in the field after treatments. We discuss why neither pesticide should be taken into account for integrated pest management programs.

  1. Leaf surface and histological perturbations of leaves of Phaseolus vulgaris and Helianthus annuus after exposure to simulated acid rain

    Energy Technology Data Exchange (ETDEWEB)

    Evans, L.S. (Manhattan Coll., Bronx, NY); Gmur, N.F.; Da Costa, F.

    1977-08-01

    Initial injury to adaxial leaf surfaces of Phaseolus vulgaris and Helianthus annuus occurred near trichomes and stomata after exposure to simulated sulfate acid rain. Lesion frequency was not correlated with density of either stomata or trichomes but was correlated with degree of leaf expansion. The number of lesions per unit area increased with total leaf area. Results suggest that characteristics of the leaf indumentum such as development of trichomes and guard cells and/or cuticle thickness near these structures may be involved in lesion development. Adaxial epidermal cell collapse was the first event in lesion development. Palisade cells and eventually spongy mesophyll cells collapsed after continued, daily exposure to simulated rain of low pH. Lesion development on Phaseolus vulgaris followed a specific course of events after exposure to simulated rain of known composition, application rate, drop size frequency, drop velocities, and frequency of exposures. These results allow development of further experiments to observe accurately other parameters, such as nutrient inputs and nutrient leaching from foliage, after exposure to simulated sulfate acid rain.

  2. A high proportion of blue light increases the photosynthesis capacity and leaf formation rate of Rosa × hybrida but does not affect time to flower opening.

    Science.gov (United States)

    Terfa, Meseret Tesema; Solhaug, Knut Asbjørn; Gislerød, Hans Ragnar; Olsen, Jorunn Elisabeth; Torre, Sissel

    2013-05-01

    Alterations in light quality affect plant morphogenesis and photosynthetic responses but the effects vary significantly between species. Roses exhibit an irradiance-dependent flowering control but knowledge on light quality responses is scarce. In this study we analyzed, the responses in morphology, photosynthesis and flowering of Rosa × hybrida to different blue (B) light proportions provided by light-emitting diodes (LED, high B 20%) and high pressure sodium (HPS, low B 5%) lamps. There was a strong morphological and growth effect of the light sources but no significant difference in total dry matter production and flowering. HPS-grown plants had significantly higher leaf area and plant height, yet a higher dry weight proportion was allocated to leaves than stems under LED. LED plants showed 20% higher photosynthetic capacity (Amax ) and higher levels of soluble carbohydrates. The increase in Amax correlated with an increase in leaf mass per unit leaf area, higher stomata conductance and CO2 exchange, total chlorophyll (Chl) content per area and Chl a/b ratio. LED-grown leaves also displayed a more sun-type leaf anatomy with more and longer palisade cells and a higher stomata frequency. Although floral initiation occurred at a higher leaf number in LED, the time to open flowers was the same under both light conditions. Thereby the study shows that a higher portion of B light is efficient in increasing photosynthesis performance per unit leaf area, enhancing growth and morphological changes in roses but does not affect the total Dry Matter (DM) production or time to open flower.

  3. Factors affecting the abundance of leaf-litter arthropods in unburned and thrice-burned seasonally-dry Amazonian forests.

    Directory of Open Access Journals (Sweden)

    Juliana M Silveira

    Full Text Available Fire is frequently used as a land management tool for cattle ranching and annual crops in the Amazon. However, these maintenance fires often escape into surrounding forests, with potentially severe impacts for forest biodiversity. We examined the effect of experimental fires on leaf-litter arthropod abundance in a seasonally-dry forest in the Brazilian Amazon. The study plots (50 ha each included a thrice-burned forest and an unburned control forest. Pitfall-trap samples were collected at 160 randomly selected points in both plots, with sampling stratified across four intra-annual replicates across the dry and wet seasons, corresponding to 6, 8, 10 and 12 months after the most recent fire. Arthropods were identified to the level of order (separating Formicidae. In order to better understand the processes that determine arthropod abundance in thrice-burned forests, we measured canopy openness, understory density and litter depth. All arthropod taxa were significantly affected by fire and season. In addition, the interactions between burn treatment and season were highly significant for all taxa but Isoptera. The burned plot was characterized by a more open canopy, lower understory density and shallower litter depth. Hierarchical partitioning revealed that canopy openness was the most important factor explaining arthropod order abundances in the thrice-burned plot, whereas all three environmental variables were significant in the unburned control plot. These results reveal the marked impact of recurrent wildfires and seasonality on litter arthropods in this transitional forest, and demonstrate the overwhelming importance of canopy-openness in driving post-fire arthropod abundance.

  4. Optimization of RNA isolation from Brittle Leaf Disease affected date palm leaves and construction of a subtractive cDNA library.

    Science.gov (United States)

    Saïdi, Mohammed Najib; Gargouri-Bouzid, Radhia; Rayanni, Mariem; Drira, Noureddine

    2009-01-01

    A simple and efficient method was described here for the isolation of high-quality RNA from date palm leaves affected with Brittle Leaf Disease (BLD) and containing high amount of phenolic compounds. The procedure was based on the use of a non-ionic detergent Nonidet-P40 (NP-40), Polyvinylpyrrolidone (PVP), and beta-mercaptoethanol in the extraction buffer in order to isolate cytoplasmic RNA and to prevent the oxidation of phenolic compounds. This method allowed the isolation of intact RNA, suitable for cDNA synthesis and library construction. Differential screening of the subtractive cDNA library from affected leaf RNA led to the identification of some BLD-induced genes.

  5. Exploration mode affects visuohaptic integration of surface orientation.

    Science.gov (United States)

    Plaisier, Myrthe A; van Dam, Loes C J; Glowania, Catharina; Ernst, Marc O

    2014-11-20

    We experience the world mostly in a multisensory fashion using a combination of all of our senses. Depending on the modality we can select different exploration strategies for extracting perceptual information. For instance, using touch we can enclose an object in our hand to explore parts of the object in parallel. Alternatively, we can trace the object with a single finger to explore its parts in a serial fashion. In this study we investigated whether the exploration mode (parallel vs. serial) affects the way sensory signals are combined. To this end, participants visually and haptically explored surfaces that varied in roll angle and indicated which side of the surface was perceived as higher. In Experiment 1, the exploration mode was the same for both modalities (i.e., both parallel or both serial). In Experiment 2, we introduced a difference in exploration mode between the two modalities (visual exploration was parallel while haptic exploration was serial or vice versa). The results showed that visual and haptic signals were combined in a statistically optimal fashion only when the exploration modes were the same. In case of an asymmetry in the exploration modes across modalities, integration was suboptimal. This indicates that spatial-temporal discrepancies in the acquisition of information in the two senses (i.e., haptic and visual) can lead to the breakdown of sensory integration.

  6. Extraction of bioactive compounds and free radical scavenging activity of purple basil (Ocimum basilicum L.) leaf extracts as affected by temperature and time

    OpenAIRE

    PEDRO,ALESSANDRA C.; FERNANDA MOREIRA; DANIEL GRANATO; ROSSO,NEIVA D.

    2016-01-01

    In the current study, response surface methodology (RSM) was used to assess the effects of extraction time and temperature on the content of bioactive compounds and antioxidant activity of purple basil leaf (Ocimum basilicum L.) extracts. The stability of anthocyanins in relation to temperature, light and copigmentation was also studied. The highest anthocyanin content was 67.40 mg/100 g extracted at 30 °C and 60 min. The degradation of anthocyanins with varying temperatures and in the presen...

  7. Fruit load and canopy shading affect leaf characteristics and net gas exchange of 'Spring' navel orange trees.

    Science.gov (United States)

    Syvertsen, J P; Goñi, C; Otero, A

    2003-09-01

    Five-year-old 'Spring' navel (Citrus sinensis (L.) Osbeck) orange trees were completely defruited, 50% defruited or left fully laden to study effects of fruit load on concentrations of nitrogen (N) and carbohydrate, net assimilation of CO2 (Ac) and stomatal conductance (gs) of mature leaves on clear winter days just before fruit harvest. Leaves on defruited trees were larger, had higher starch concentrations and greater leaf dry mass per area (LDMa) than leaves on fruited trees. Both Ac and gs were more than 40% lower in sunlit leaves on defruited trees than in sunlit leaves on trees with fruit. Leaves immediately adjacent to fruit were smaller, had lower leaf nitrogen and carbohydrate concentrations, lower LDMa and lower Ac than leaves on non-fruiting branches of the same trees. Removing half the crop increased individual fruit mass, but reduced fruit color development. Half the trees were shaded with 50% shade cloth for 4 months before harvest to determine the effects of lower leaf temperature (Tl) and leaf-to-air vapor pressure difference on leaf responses. On relatively warm days when sunlit Tl > 25 degrees C, shade increased Ac and gs, but had no effect on the ratio of internal to ambient CO2 (Ci/Ca) concentration in leaves, implying that high mesophyll temperatures in sunlit leaves were more important than gs in limiting Ac. Sunlit leaves were more photoinhibited than shaded leaves on cooler days when Tl fruit size, but shaded fruit developed better external color than sun-exposed fruit. Overall, the presence of a normal fruit crop resulted in lower foliar carbohydrate concentrations and higher Ac compared with defruited trees, except on warm days when Ac was reduced by high leaf temperatures.

  8. Effect of copper deficiency and of water stress on the microstructure of tomato leaf surface

    OpenAIRE

    Barbara Dyki; Jan Borowski; Waldemar Kowalczyk

    2013-01-01

    The reaction of tomato plants cv. Tukan F1 to copper deficiency and to water stress was compared. Plants grown in copper deficiency and in conditions of water stress were significantly smaller than controls. They had also lower turgor. The epidermis cells of the upper side leaf in the plants growing in copper deficiency or water stress conditions were smaller than in control plants. However the stomata and trichomes number of leaves plants with copper or water deficiency grown were bigger in ...

  9. Does long-term fungicide exposure affect the reproductive performance of leaf-shredders? A partial life-cycle study using Hyalella azteca.

    Science.gov (United States)

    Baudy, Patrick; Zubrod, Jochen P; Konschak, Marco; Weil, Mirco; Schulz, Ralf; Bundschuh, Mirco

    2017-03-01

    Leaf-shredding amphipods play a critical role in the ecosystem function of leaf litter breakdown, a key process in many low order streams. Fungicides, however, may adversely influence shredders' behavior and the functions they provide, while there is only limited knowledge concerning effects on their reproductive performance. To assess the latter, a semi-static 56-day partial life-cycle bioassay using the model shredder Hyalella azteca (n = 30) was performed applying two environmentally relevant concentrations of a model fungicide mixture (i.e., 5 and 25 μg/L) composed of five fungicides with different modes of toxic action. Variables related to the food processing (leaf consumption and feces production), growth (body length and dry weight), energy reserves (lipid content), and reproduction (amplexus pairs, number and length of offspring) were determined to understand potential implications in the organisms' energy budget. While the fungicides did not affect leaf consumption, both fungicide treatments significantly reduced amphipods' feces production (∼20%) compared to the control. This observation suggests an increased food utilization to counteract the elevated and stress-related energy demand: although growth as well as energy reserves were unaffected, amplexus pairs were less frequently observed in both fungicide treatments (∼50-100%) suggesting a tradeoff regarding energy allocation favoring the maintenance of fundamental functions at the organism level over reproduction. As a result, the time to release of first offspring was delayed in both fungicide treatments (7 and 14 days) and the median number of offspring was significantly lower in the 25-μg/L treatment (100%), whereas offspring length remained unaffected. The results of this study thus indicate that chronic fungicide exposures can negatively impact shredders' reproductive performance. This may translate into lower abundances and thus a reduced contribution to leaf litter breakdown in

  10. RNAi-mediated downregulation of poplar plasma membrane intrinsic proteins (PIPs) changes plasma membrane proteome composition and affects leaf physiology.

    Science.gov (United States)

    Bi, Zhen; Merl-Pham, Juliane; Uehlein, Norbert; Zimmer, Ina; Mühlhans, Stefanie; Aichler, Michaela; Walch, Axel Karl; Kaldenhoff, Ralf; Palme, Klaus; Schnitzler, Jörg-Peter; Block, Katja

    2015-10-14

    Plasma membrane intrinsic proteins (PIPs) are one subfamily of aquaporins that mediate the transmembrane transport of water. To reveal their function in poplar, we generated transgenic poplar plants in which the translation of PIP genes was downregulated by RNA interference investigated these plants with a comprehensive leaf plasma membrane proteome and physiome analysis. First, inhibition of PIP synthesis strongly altered the leaf plasma membrane protein composition. Strikingly, several signaling components and transporters involved in the regulation of stomatal movement were differentially regulated in transgenic poplars. Furthermore, hormonal crosstalk related to abscisic acid, auxin and brassinosteroids was altered, in addition to cell wall biosynthesis/cutinization, the organization of cellular structures and membrane trafficking. A physiological analysis confirmed the proteomic results. The leaves had wider opened stomata and higher net CO2 assimilation and transpiration rates as well as greater mesophyll conductance for CO2 (gm) and leaf hydraulic conductance (Kleaf). Based on these results, we conclude that PIP proteins not only play essential roles in whole leaf water and CO2 flux but have important roles in the regulation of stomatal movement.

  11. Evaporative properties and pinning strength of laser-ablated, hydrophilic sites on lotus-leaf-like, nanostructured surfaces.

    Science.gov (United States)

    McLauchlin, Melissa L; Yang, Dongqing; Aella, P; Garcia, Antonio A; Picraux, S T; Hayes, Mark A

    2007-04-24

    Wetting, evaporative, and pinning strength properties of hydrophilic sites on superhydrophobic, nanostructured surfaces were examined. Understanding these properties is important for surface characterization and designing features in self-cleaning, lotus-leaf-like surfaces. Laser-ablated, hydrophilic spots between 250 mum and 2 mm in diameter were prepared on silicon nanowire (NW) superhydrophobic surfaces. For larger circumference pinning sites, initial contact angle measurements resemble the contact angle of the surface within the pinning site: 65-69 degrees . As the drop volume is increased, the contact angles approach the contact angle of the NW surface without pinning sites: 171-176 degrees . The behavior of water droplets on the pinning sites is governed by how much of the water droplet is being influenced by the superhydrophobic NW surfaces versus the hydrophilic areas. During the evaporation of sinapic acid solution, drops are pinned by the spots except for the smaller circumference sites. Pinning strengths of the hydrophilic sites are a linear function of the pinning spot circumference. Protein samples prepared and deposited on the pinning sites for analysis by matrix-assisted laser desorption ionization indicate an improvement in sensitivity from that of a standard plate analysis by a factor of 5.

  12. Effect of copper deficiency and of water stress on the microstructure of tomato leaf surface

    Directory of Open Access Journals (Sweden)

    Barbara Dyki

    2013-12-01

    Full Text Available The reaction of tomato plants cv. Tukan F1 to copper deficiency and to water stress was compared. Plants grown in copper deficiency and in conditions of water stress were significantly smaller than controls. They had also lower turgor. The epidermis cells of the upper side leaf in the plants growing in copper deficiency or water stress conditions were smaller than in control plants. However the stomata and trichomes number of leaves plants with copper or water deficiency grown were bigger in comparision with control. The pores of stomata were always larger in leaves of control plants than in other objects.

  13. Biodiesel Production from Non-Edible Beauty Leaf (Calophyllum inophyllum Oil: Process Optimization Using Response Surface Methodology (RSM

    Directory of Open Access Journals (Sweden)

    Mohammad I. Jahirul

    2014-08-01

    Full Text Available In recent years, the beauty leaf plant (Calophyllum Inophyllum is being considered as a potential 2nd generation biodiesel source due to high seed oil content, high fruit production rate, simple cultivation and ability to grow in a wide range of climate conditions. However, however, due to the high free fatty acid (FFA content in this oil, the potential of this biodiesel feedstock is still unrealized, and little research has been undertaken on it. In this study, transesterification of beauty leaf oil to produce biodiesel has been investigated. A two-step biodiesel conversion method consisting of acid catalysed pre-esterification and alkali catalysed transesterification has been utilized. The three main factors that drive the biodiesel (fatty acid methyl ester (FAME conversion from vegetable oil (triglycerides were studied using response surface methodology (RSM based on a Box-Behnken experimental design. The factors considered in this study were catalyst concentration, methanol to oil molar ratio and reaction temperature. Linear and full quadratic regression models were developed to predict FFA and FAME concentration and to optimize the reaction conditions. The significance of these factors and their interaction in both stages was determined using analysis of variance (ANOVA. The reaction conditions for the largest reduction in FFA concentration for acid catalysed pre-esterification was 30:1 methanol to oil molar ratio, 10% (w/w sulfuric acid catalyst loading and 75 °C reaction temperature. In the alkali catalysed transesterification process 7.5:1 methanol to oil molar ratio, 1% (w/w sodium methoxide catalyst loading and 55 °C reaction temperature were found to result in the highest FAME conversion. The good agreement between model outputs and experimental results demonstrated that this methodology may be useful for industrial process optimization for biodiesel production from beauty leaf oil and possibly other industrial processes as well.

  14. 不同沟灌方式下玉米叶片气孔阻力差异%Leaf stomatal resistance of maize affected by different furrow irrigation methods

    Institute of Scientific and Technical Information of China (English)

    李彩霞; 周新国; 孙景生; 李新强

    2014-01-01

    maize leaf, regardless of irrigation methods, the stomatal resistance decreased gradually from the base to the tip of the maize leaf. At the population level, the stomatal resistance of maize leaf increased gradually from canopy top to bottom. For the change of the leaf stomatal resistance in time, diurnal variation of leaf stomatal resistance was in a Wshape. Diurnal and daily changes in the leaf stomatal resistance in the upper canopy were relatively small. The upper surface of maize leaf contributed more to CO2 and water vapor transfer than the ones underside. Except at the seedling stage, the leaves in the upper and middle part of maize canopy contributed more than 80% of the total CO2 and water vapor. Stomatal resistances of maize leaves decreased with the increase in leaf age during the vegetative growth stage. Differences in stomatal resistance among maize leaves of different ages were increased by the alternative deficit water supply. During the reproductive growth phase, leaf age had no significant influence on the stomatal resistance in matured leaves. Compared with the conventional furrow irrigation with sufficient water supply, the alternative deficit water supply increased the ratio of the stomatal resistances between the upper side and underside of maize leaves. The vertical gradient of stomatal resistance from canopy top to bottom increased significantly (P<0.05), decreasing leaf stomatal conductivity rapidly, and improving the contribution of the stomatal aperture in the upper canopy to water vapor transfer. Therefore, the leaf stomatal resistance of maize was regulated by furrow irrigation methods and soil water condition, and it was affected by the leaf age, leaf area index and natural feature of stomatal aperture. The study is useful for controllable irrigation technology and water vapor cycle in soil plant atmosphere continuum (SPAC).

  15. Improving winter leaf area index estimation in coniferous forests and its significance in estimating the land surface albedo

    Science.gov (United States)

    Wang, Rong; Chen, Jing M.; Pavlic, Goran; Arain, Altaf

    2016-09-01

    Winter leaf area index (LAI) of evergreen coniferous forests exerts strong control on the interception of snow, snowmelt and energy balance. Simulation of winter LAI and associated winter processes in land surface models is challenging. Retrieving winter LAI from remote sensing data is difficult due to cloud contamination, poor illumination, lower solar elevation and higher radiation reflection by snow background. Underestimated winter LAI in evergreen coniferous forests is one of the major issues limiting the application of current remote sensing LAI products. It has not been fully addressed in past studies in the literature. In this study, we used needle lifespan to correct winter LAI in a remote sensing product developed by the University of Toronto. For the validation purpose, the corrected winter LAI was then used to calculate land surface albedo at five FLUXNET coniferous forests in Canada. The RMSE and bias values for estimated albedo were 0.05 and 0.011, respectively, for all sites. The albedo map over coniferous forests across Canada produced with corrected winter LAI showed much better agreement with the GLASS (Global LAnd Surface Satellites) albedo product than the one produced with uncorrected winter LAI. The results revealed that the corrected winter LAI yielded much greater accuracy in simulating land surface albedo, making the new LAI product an improvement over the original one. Our study will help to increase the usability of remote sensing LAI products in land surface energy budget modeling.

  16. Canopy position affects the relationships between leaf respiration and associated traits in a tropical rainforest in Far North Queensland.

    Science.gov (United States)

    Weerasinghe, Lasantha K; Creek, Danielle; Crous, Kristine Y; Xiang, Shuang; Liddell, Michael J; Turnbull, Matthew H; Atkin, Owen K

    2014-06-01

    We explored the impact of canopy position on leaf respiration (R) and associated traits in tree and shrub species growing in a lowland tropical rainforest in Far North Queensland, Australia. The range of traits quantified included: leaf R in darkness (RD) and in the light (RL; estimated using the Kok method); the temperature (T)-sensitivity of RD; light-saturated photosynthesis (Asat); leaf dry mass per unit area (LMA); and concentrations of leaf nitrogen (N), phosphorus (P), soluble sugars and starch. We found that LMA, and area-based N, P, sugars and starch concentrations were all higher in sun-exposed/upper canopy leaves, compared with their shaded/lower canopy and deep-shade/understory counterparts; similarly, area-based rates of RD, RL and Asat (at 28 °C) were all higher in the upper canopy leaves, indicating higher metabolic capacity in the upper canopy. The extent to which light inhibited R did not differ significantly between upper and lower canopy leaves, with the overall average inhibition being 32% across both canopy levels. Log-log RD-Asat relationships differed between upper and lower canopy leaves, with upper canopy leaves exhibiting higher rates of RD for a given Asat (both on an area and mass basis), as well as higher mass-based rates of RD for a given [N] and [P]. Over the 25-45 °C range, the T-sensitivity of RD was similar in upper and lower canopy leaves, with both canopy positions exhibiting Q10 values near 2.0 (i.e., doubling for every 10 °C rise in T) and Tmax values near 60 °C (i.e., T where RD reached maximal values). Thus, while rates of RD at 28 °C decreased with increasing depth in the canopy, the T-dependence of RD remained constant; these findings have important implications for vegetation-climate models that seek to predict carbon fluxes between tropical lowland rainforests and the atmosphere.

  17. Adaptative changes of leaf surface of tropical orchid Cattleya gaskelliana (N.E.Br. B.S. Williams after transferring from in vitro to ex vitro conditions

    Directory of Open Access Journals (Sweden)

    Lyudmila I. Buyun

    2013-04-01

    Full Text Available The leaf surface micromorphology of Cattleya gaskellianajuvenile plants, propagated in vitrofrom seeds, as well as of adult plants, cultivated in glasshouse, was analyzed by scanning electron microscopy (SEM. The leaves of both juvenile and adult plants are hypostomatic, their stomata are of tetracytic type. It was found that development of single stomata on the adaxial leaf surface of juvenile plants was induced byin vitro conditions. During the acclimation of in vitro propagated plants to glasshouse conditions the following changes of leaf surface micromorphology have been observed: 1 configuration of epidermal cells changed; 2 dimensions of typical epidermal cells reduced; 3 stomata density and their dimensions increased. The results suggest that structural changes, probably, can be regarded as an adaptation to avoid excessive rate leaf transpiration during a period of C. gaskelliana juvenile plants acclimation to glasshouse conditions. In the case when micromorphological leaf characteristics (stomata density per mm2, stomatal index, epidermal cells number per mm 2 of in vitro propagated plants of C. gaskelliana were comparable to those of adult plants, survival rate was more than 95%.

  18. Factors affecting surface and release properties of thin PDMS films

    DEFF Research Database (Denmark)

    Vudayagiri, Sindhu; Junker, Michael Daniel; Skov, Anne Ladegaard

    2013-01-01

    of perfluoroether allylamide (PFE) lowered the surface energy which could ease the release. This is further investigated together with an evaluation of the resulting change in actuator performance. The relationship between the adhesive energy, surface energy, Young’s modulus and peel force of the films is analyzed....

  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.

    2012-01-01

    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

  20. Corrosion inhibition of Eleusine aegyptiaca and Croton rottleri leaf extracts on cast iron surface in 1 M HCl medium

    Science.gov (United States)

    Rajeswari, Velayutham; Kesavan, Devarayan; Gopiraman, Mayakrishnan; Viswanathamurthi, Periasamy; Poonkuzhali, Kaliyaperumal; Palvannan, Thayumanavan

    2014-09-01

    The adsorption and corrosion inhibition activities of Eleusine aegyptiaca (E. aegyptiaca) and Croton rottleri (C. rottleri) leaf extracts on cast iron corrosion in 1 M hydrochloric acid solution were studied first time by weight loss and electrochemical techniques viz., Tafel polarization and electrochemical impedance spectroscopy. The results obtained from the weight loss and electrochemical methods showed that the inhibition efficiency increased with inhibitor concentrations. It was found that the extracts acted as mixed-type inhibitors. The addition of halide additives (KCl, KBr, and KI) on the inhibition efficiency has also been investigated. The adsorption of the inhibitors on cast iron surface both in the presence and absence of halides follows the Langmuir adsorption isotherm model. The inhibiting nature of the inhibitors was supported by FT-IR, UV-vis, Wide-angle X-ray diffraction and SEM methods.

  1. Anatomical structure and surface micromorphology of tomatillo leaf and flower (Physalis ixocarpa Brot., Solanaceae

    Directory of Open Access Journals (Sweden)

    Barbara Dyki

    2014-01-01

    Full Text Available Tomatillo (Physalis ixocarpa Brot. is a newly introduced cultivated plant in Poland. Its anatomy was investigated in light and scanning electron microscopes. Tomatillo adult leaf had one layer of palisade parenchyma. The 1-2 cell layers of spongy parenchyma situated just below the palisade parenchyma showed large, tightly packed cells with great druses. The remaining spongy parenchyma was built of cells showing several extensions. Peculiarity of the sepals were the stomata situated on columns or hills formed of many cells. The petals had a very loose mesophyl. Their adaxial epidermis was composed of papillate cells. Such structure of the petal epidermis probably contributes to light dispersion and prevents glittering. There were several types of trichomes on the leaves, sepals and petals, some of them glandular and some simple. The large, very ramified, dendritic trichomes situated on the petals at the entry to the ovary might eventually protect it against excessive drying. The pollen grain was spherical, three-colpate. The style had a hollow channel inside. The stigma was of a wet, pa-pillate type. Sometimes thorny trichomes were found among papillae.

  2. Effects of simulated acid rain on leaf cuticular characteristics and surface properties

    Energy Technology Data Exchange (ETDEWEB)

    Percy, K.E.

    1987-01-01

    The effects of simulated acid rain (SAR) on adaxial leaf cuticles were investigated for a group of plant species selected from commercially-important crops and trees which exhibited markedly different cuticular characteristics. Expanding leaves of controlled-environment grown plants were exposed from emergence to full expansion to pH 5.6, 4.6, 4.2, 3.8, 3.4, 3.0 or 2.6 simulated rain (SAR) applied at 2 mm/h on alternate days. The number of events, the amount, droplet size and velocity were representative of UK ambient rainfall characteristics. The non-acidic pH 5.6 simulated rain consisted of 14 inorganic ions in weight/volume concentrations equivalent to those measured at a site in Eastern Canada. The degree of foliar injury and size of lesions was greater on crop species with waxy leaves than those with non-waxy leaves. Injury was least on needles of Sitka spruce (Picea sitchensis (Bong.) Carr.). The relative sensitivity of the species examined to foliar injury decreased in the order: field rap (Brassica napus L.) > Eucalyptus globulus L.) > pea (Pisum sativum L.) > dwarf bean (Phaseolus vulgaris L.) > field bean (Vicia faba L.) > Sitka spruce.

  3. Knockdown of WHIRLY1 Affects Drought Stress-Induced Leaf Senescence and Histone Modifications of the Senescence-Associated Gene HvS40

    Science.gov (United States)

    Janack, Bianka; Sosoi, Paula; Krupinska, Karin; Humbeck, Klaus

    2016-01-01

    The plastid-nucleus located protein WHIRLY1 has been described as an upstream regulator of leaf senescence, binding to the promoter of senescence-associated genes like HvS40. To investigate the impact of WHIRLY1 on drought stress-induced, premature senescence, transgenic barley plants with an RNAi-mediated knockdown of the HvWHIRLY1 gene were grown under normal and drought stress conditions. The course of leaf senescence in these lines was monitored by physiological parameters and studies on the expression of senescence- and drought stress-related genes. Drought treatment accelerated leaf senescence in WT plants, whereas WHIRLY 1 knockdown lines (RNAi-W1) showed a stay-green phenotype. Expression of both senescence-associated and drought stress-responsive genes, was delayed in the transgenic plants. Notably, expression of transcription factors of the WRKY and NAC families, which are known to function in senescence- and stress-related signaling pathways, was affected in plants with impaired accumulation of WHIRLY1, indicating that WHIRLY1 acts as an upstream regulator of drought stress-induced senescence. To reveal the epigenetic indexing of HvS40 at the onset of drought-induced senescence in WT and RNAi-W1 lines, stress-responsive loading with histone modifications of promoter and coding sequences of HvS40 was analyzed by chromatin immunoprecipitation and quantified by qRT-PCR. In the wildtype, the euchromatic mark H3K9ac of the HvS40 gene was low under control conditions and was established in response to drought treatment, indicating the action of epigenetic mechanisms in response to drought stress. However, drought stress caused no significant increase in H3K9ac in plants impaired in accumulation of WHIRLY1. The results show that WHIRLY1 knockdown sets in motion a delay in senescence that involves all aspects of gene expression, including changes in chromatin structure. PMID:27608048

  4. Knockdown of WHIRLY1 Affects Drought Stress-Induced Leaf Senescence and Histone Modifications of the Senescence-Associated Gene HvS40

    Directory of Open Access Journals (Sweden)

    Bianka Janack

    2016-09-01

    Full Text Available The plastid-nucleus located protein WHIRLY1 has been described as an upstream regulator of leaf senescence, binding to the promoter of senescence-associated genes like HvS40. To investigate the impact of WHIRLY1 on drought stress-induced, premature senescence, transgenic barley plants with an RNAi-mediated knockdown of the HvWHIRLY1 gene were grown under normal and drought stress conditions. The course of leaf senescence in these lines was monitored by physiological parameters and studies on the expression of senescence- and drought stress-related genes. Drought treatment accelerated leaf senescence in WT plants, whereas WHIRLY 1 knockdown lines (RNAi-W1 showed a stay-green phenotype. Expression of both senescence-associated and drought stress-responsive genes, was delayed in the transgenic plants. Notably, expression of transcription factors of the WRKY and NAC families, which are known to function in senescence- and stress-related signaling pathways, was affected in plants with impaired accumulation of WHIRLY1, indicating that WHIRLY1 acts as an upstream regulator of drought stress-induced senescence. To reveal the epigenetic indexing of HvS40 at the onset of drought-induced senescence in WT and RNAi-W1 lines, stress-responsive loading with histone modifications of promoter and coding sequences of HvS40 was analyzed by chromatin immunoprecipitation and quantified by qRT-PCR. In the wildtype, the euchromatic mark H3K9ac of the HvS40 gene was low under control conditions and was established in response to drought treatment, indicating the action of epigenetic mechanisms in response to drought stress. However, drought stress caused no significant increase in H3K9ac in plants impaired in accumulation of WHIRLY1. The results show that WHIRLY1 knockdown sets in motion a delay in senescence that involves all aspects of gene expression, including changes in chromatin structure.

  5. Plant surface wax affects parasitoid's response to host footprints

    Science.gov (United States)

    Rostás, Michael; Ruf, Daniel; Zabka, Vanessa; Hildebrandt, Ulrich

    2008-10-01

    The plant surface is the substrate upon which herbivorous insects and natural enemies meet and thus represents the stage for interactions between the three trophic levels. Plant surfaces are covered by an epicuticular wax layer which is highly variable depending on species, cultivar or plant part. Differences in wax chemistry may modulate ecological interactions. We explored whether caterpillars of Spodoptera frugiperda, when walking over a plant surface, leave a chemical trail (kairomones) that can be detected by the parasitoid Cotesia marginiventris. Chemistry and micromorphology of cuticular waxes of two barley eceriferum wax mutants ( cer-za.126, cer-yp.949) and wild-type cv. Bonus (wt) were assessed. The plants were then used to investigate potential surface effects on the detectability of caterpillar kairomones. Here we provide evidence that C. marginiventris responds to chemical footprints of its host. Parasitoids were able to detect the kairomone on wild-type plants and on both cer mutants but the response to cer-yp.949 (reduced wax, high aldehyde fraction) was less pronounced. Experiments with caterpillar-treated wt and mutant leaves offered simultaneously, confirmed this observation: no difference in wasp response was found when wt was tested against cer-za.126 (reduced wax, wt-like chemical composition) but wt was significantly more attractive than cer-yp.949. This demonstrates for the first time that the wax layer can modulate the detectability of host kairomones.

  6. Factors Affecting Peptide Interactions with Surface-Bound Microgels

    OpenAIRE

    2016-01-01

    Effects of electrostatics and peptide size on peptide interactions with surface-bound microgels were investigated with ellipsometry, confocal microscopy, and atomic force microscopy (AFM). Results show that binding of cationic poly-L-lysine (pLys) to anionic, covalently immobilized, poly(ethyl acrylate-co-methacrylic acid) microgels increased with increasing peptide net charge and microgel charge density. Furthermore, peptide release was facilitated by decreasing either microgel or peptide ch...

  7. Corrosion inhibition of Eleusine aegyptiaca and Croton rottleri leaf extracts on cast iron surface in 1 M HCl medium

    Energy Technology Data Exchange (ETDEWEB)

    Rajeswari, Velayutham [Department of Chemistry, Periyar University, Salem 636011 (India); Kesavan, Devarayan [Department of Chemistry, Dhirajlal Gandhi College of Technology, Salem 636309 (India); Gopiraman, Mayakrishnan [Department of Chemistry, National Institute of Technology, Tiruchirappalli 620015 (India); Viswanathamurthi, Periasamy, E-mail: viswanathamurthi72@gmail.com [Department of Chemistry, Periyar University, Salem 636011 (India); Poonkuzhali, Kaliyaperumal; Palvannan, Thayumanavan [Department of Bio-Chemistry, Periyar University, Salem 636011 (India)

    2014-09-30

    Graphical abstract: - Highlights: • Eleusine aegyptiaca and Croton rottleri are commonly available, less-toxic and eco-friendly inhibitors for cast iron corrosion. • The active constituents present in extracts adsorbed on the iron surface to inhibit the acidic corrosion. • The higher values of E{sub a} and ΔH{sup *} point out the higher inhibition efficiency noticed for the inhibitors. • Weight loss methods at various temperature and spectral data provides evidence for adsorption mechanism of inhibitors. - Abstract: The adsorption and corrosion inhibition activities of Eleusine aegyptiaca (E. aegyptiaca) and Croton rottleri (C. rottleri) leaf extracts on cast iron corrosion in 1 M hydrochloric acid solution were studied first time by weight loss and electrochemical techniques viz., Tafel polarization and electrochemical impedance spectroscopy. The results obtained from the weight loss and electrochemical methods showed that the inhibition efficiency increased with inhibitor concentrations. It was found that the extracts acted as mixed-type inhibitors. The addition of halide additives (KCl, KBr, and KI) on the inhibition efficiency has also been investigated. The adsorption of the inhibitors on cast iron surface both in the presence and absence of halides follows the Langmuir adsorption isotherm model. The inhibiting nature of the inhibitors was supported by FT-IR, UV–vis, Wide-angle X-ray diffraction and SEM methods.

  8. Solanum tuberosum and Lycopersicon esculentum Leaf Extracts and Single Metabolites Affect Development and Reproduction of Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Emanuela Ventrella

    Full Text Available Glycoalkaloids are secondary metabolites commonly found in Solanaceae plants. They have anti-bacterial, anti-fungal and insecticidal activities. In the present study we examine the effects of potato and tomato leaf extracts and their main components, the glycoalkaloids α-solanine, α-chaconine and α-tomatine, on development and reproduction of Drosophila melanogaster wild-type flies at different stages. Parental generation was exposed to five different concentrations of tested substances. The effects were examined also on the next, non-exposed generation. In the first (exposed generation, addition of each extract reduced the number of organisms reaching the pupal and imaginal stages. Parent insects exposed to extracts and metabolites individually applied showed faster development. However, the effect was weaker in case of single metabolites than in case of exposure to extracts. An increase of developmental rate was also observed in the next, non-exposed generation. The imagoes of both generations exposed to extracts and pure metabolites showed some anomalies in body size and malformations, such as deformed wings and abdomens, smaller black abdominal zone. Our results further support the current idea that Solanaceae can be an impressive source of molecules, which could efficaciously be used in crop protection, as natural extract or in formulation of single pure metabolites in sustainable agriculture.

  9. Solanum tuberosum and Lycopersicon esculentum Leaf Extracts and Single Metabolites Affect Development and Reproduction of Drosophila melanogaster

    Science.gov (United States)

    Ventrella, Emanuela; Adamski, Zbigniew; Chudzińska, Ewa; Miądowicz-Kobielska, Mariola; Marciniak, Paweł; Büyükgüzel, Ender; Büyükgüzel, Kemal; Erdem, Meltem; Falabella, Patrizia; Scrano, Laura; Bufo, Sabino Aurelio

    2016-01-01

    Glycoalkaloids are secondary metabolites commonly found in Solanaceae plants. They have anti-bacterial, anti-fungal and insecticidal activities. In the present study we examine the effects of potato and tomato leaf extracts and their main components, the glycoalkaloids α-solanine, α-chaconine and α-tomatine, on development and reproduction of Drosophila melanogaster wild-type flies at different stages. Parental generation was exposed to five different concentrations of tested substances. The effects were examined also on the next, non-exposed generation. In the first (exposed) generation, addition of each extract reduced the number of organisms reaching the pupal and imaginal stages. Parent insects exposed to extracts and metabolites individually applied showed faster development. However, the effect was weaker in case of single metabolites than in case of exposure to extracts. An increase of developmental rate was also observed in the next, non-exposed generation. The imagoes of both generations exposed to extracts and pure metabolites showed some anomalies in body size and malformations, such as deformed wings and abdomens, smaller black abdominal zone. Our results further support the current idea that Solanaceae can be an impressive source of molecules, which could efficaciously be used in crop protection, as natural extract or in formulation of single pure metabolites in sustainable agriculture. PMID:27213896

  10. Rosmarinus officinalis L. leaf extract improves memory impairment and affects acetylcholinesterase and butyrylcholinesterase activities in rat brain.

    Science.gov (United States)

    Ozarowski, Marcin; Mikolajczak, Przemyslaw L; Bogacz, Anna; Gryszczynska, Agnieszka; Kujawska, Malgorzata; Jodynis-Liebert, Jadwiga; Piasecka, Anna; Napieczynska, Hanna; Szulc, Michał; Kujawski, Radoslaw; Bartkowiak-Wieczorek, Joanna; Cichocka, Joanna; Bobkiewicz-Kozlowska, Teresa; Czerny, Boguslaw; Mrozikiewicz, Przemyslaw M

    2013-12-01

    Rosmarinus officinalis L. leaf as part of a diet and medication can be a valuable proposal for the prevention and treatment of dementia. The aim of the study was to assess the effects of subchronic (28-fold) administration of a plant extract (RE) (200 mg/kg, p.o.) on behavioral and cognitive responses of rats linked with acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activity and their mRNA expression level in the hippocampus and frontal cortex. The passive avoidance test results showed that RE improved long-term memory in scopolamine-induced rats. The extract inhibited the AChE activity and showed a stimulatory effect on BuChE in both parts of rat brain. Moreover, RE produced a lower mRNA BuChE expression in the cortex and simultaneously an increase in the hippocampus. The study suggests that RE led to improved long-term memory in rats, which can be partially explained by its inhibition of AChE activity in rat brain.

  11. Leaf senescence of common bean plants as affected by soil phosphorus supply Senescência foliar do feijoeiro afetada pelo suprimento de fósforo no solo

    Directory of Open Access Journals (Sweden)

    Adelson Paulo Araújo

    2007-06-01

    Full Text Available Responses of leaf senescence to P supply could constitute adaptive mechanisms for plant growth under P-limiting conditions. The aim of this study was to evaluate the effects of soil P supply on leaf senescence of common bean (Phaseolus vulgaris L.. Eight P levels, ranging from 5 to 640 mg kg-1 P, were applied to pots containing four bean plants of cultivar Carioca in 10 kg of an Oxic Haplustult soil. Attached leaves were counted weekly, abscised leaves were collected every other day, and seeds were harvested at maturity. The number of live leaves increased until 48 days after emergence (DAE and decreased afterwards, irrespective of applied P levels. At lower applied P levels, the initial increase and the final decrease of leaf number was weak, whereas at higher applied P levels the leaf number increased intensively at the beginning of the growth cycle and decreased strongly after 48 DAE. Dry matter and P accumulated in senesced leaves increased as soil P levels increased until 61 DAE, but differences between P treatments narrowed thereafter. The greatest amounts of dry mass and P deposited by senesced leaves were observed at 48-54 DAE for high P levels, at 62-68 DAE for intermediate P levels and at 69-76 DAE for low P levels. These results indicate that soil P supply did not affect the stage of maximal leaf number and the beginning of leaf senescence of common bean plants, but the stage of greatest deposition of senesced leaves occurred earlier in the growth cycle as the soil P supply was raised.As respostas da senescência foliar ao suprimento de P podem constituir estratégias adaptativas para o crescimento vegetal sob condições limitantes do nutriente. O objetivo deste trabalho foi avaliar os efeitos do suprimento de P no solo na senescência foliar do feijoeiro (Phaseolus vulgaris L.. Oito doses de P, variando entre 5 e 640 mg kg-1 de P, foram aplicadas em vasos com 10 kg de Argissolo óxico, onde foram crescidas quatro plantas da cultivar

  12. Factors affecting population dynamics of leaf beetles in a subarctic region: The interplay between climate warming and pollution decline.

    Science.gov (United States)

    Zvereva, Elena L; Hunter, Mark D; Zverev, Vitali; Kozlov, Mikhail V

    2016-10-01

    Understanding the mechanisms by which abiotic drivers, such as climate and pollution, influence population dynamics of animals is important for our ability to predict the population trajectories of individual species under different global change scenarios. We monitored four leaf beetle species (Coleoptera: Chrysomelidae) feeding on willows (Salix spp.) in 13 sites along a pollution gradient in subarctic forests of north-western Russia from 1993 to 2014. During a subset of years, we also measured the impacts of natural enemies and host plant quality on the performance of one of these species, Chrysomela lapponica. Spring and fall temperatures increased by 2.5-3°C during the 21-year observation period, while emissions of sulfur dioxide and heavy metals from the nickel-copper smelter at Monchegorsk decreased fivefold. However, contrary to predictions of increasing herbivory with climate warming, and in spite of discovered increase in host plant quality with increase in temperatures, none of the beetle species became more abundant during the past 20years. No directional trends were observed in densities of either Phratora vitellinae or Plagiodera versicolora, whereas densities of both C. lapponica and Gonioctena pallida showed a simultaneous rapid 20-fold decline in the early 2000s, remaining at very low levels thereafter. Time series analysis and model selection indicated that these abrupt population declines were associated with decreases in aerial emissions from the smelter. Observed declines in the population densities of C. lapponica can be explained by increases in mortality from natural enemies due to the combined action of climate warming and declining pollution. This pattern suggests that at least in some tri-trophic systems, top-down factors override bottom-up effects and govern the impacts of environmental changes on insect herbivores.

  13. On the surface physics affecting solar oscillation frequencies

    Science.gov (United States)

    Houdek, G.; Trampedach, R.; Aarslev, M. J.; Christensen-Dalsgaard, J.

    2017-01-01

    Adiabatic oscillation frequencies of stellar models, computed with the standard mixing-length formulation for convection, increasingly deviate with radial order from observations in solar-like stars. Standard solar models overestimate adiabatic frequencies by as much as ˜ 20 μHz. In this Letter, we address the physical processes of turbulent convection that are predominantly responsible for the frequency differences between standard models and observations, also called `surface effects'. We compare measured solar frequencies from the Michelson Doppler Imager instrument on the SOlar and Heliospheric Observatory spacecraft with frequency calculations that include 3D hydrodynamical simulation results in the equilibrium model, non-adiabatic effects, and a consistent treatment of the turbulent pressure in both the equilibrium and stability computations. With the consistent inclusion of the above physics in our model computation, we are able to reproduce the observed solar frequencies to ≲3 μHz without the need of any additional ad hoc functional corrections.

  14. On the surface physics affecting solar oscillation frequencies

    CERN Document Server

    Houdek, G; Aarslev, M J; Christensen-Dalsgaard, J

    2016-01-01

    Adiabatic oscillation frequencies of stellar models, computed with the standard mixing-length formulation for convection, increasingly deviate with radial order from observations in solar-like stars. Standard solar models overestimate adiabatic frequencies by as much as ~ 20 {\\mu}Hz. In this letter, we address the physical processes of turbulent convection that are predominantly responsible for the frequency differences between standard models and observations, also called `surface effects'. We compare measured solar frequencies from the MDI instrument on the SOHO spacecraft with frequency calculations that include three-dimensional (3D) hydrodynamical simulation results in the equilibrium model, nonadiabatic effects, and a consistent treatment of the turbulent pressure in both the equilibrium and stability computations. With the consistent inclusion of the above physics in our model computation we are able to reproduce the observed solar frequencies to < 3 {\\mu}Hz without the need of any additional ad-hoc...

  15. Do the energy fluxes and surface conductance of boreal coniferous forests in Europe scale with leaf area?

    Science.gov (United States)

    Launiainen, Samuli; Katul, Gabriel G; Kolari, Pasi; Lindroth, Anders; Lohila, Annalea; Aurela, Mika; Varlagin, Andrej; Grelle, Achim; Vesala, Timo

    2016-12-01

    Earth observing systems are now routinely used to infer leaf area index (LAI) given its significance in spatial aggregation of land surface fluxes. Whether LAI is an appropriate scaling parameter for daytime growing season energy budget, surface conductance (Gs ), water- and light-use efficiency and surface-atmosphere coupling of European boreal coniferous forests was explored using eddy-covariance (EC) energy and CO2 fluxes. The observed scaling relations were then explained using a biophysical multilayer soil-vegetation-atmosphere transfer model as well as by a bulk Gs representation. The LAI variations significantly alter radiation regime, within-canopy microclimate, sink/source distributions of CO2 , H2 O and heat, and forest floor fluxes. The contribution of forest floor to ecosystem-scale energy exchange is shown to decrease asymptotically with increased LAI, as expected. Compared with other energy budget components, dry-canopy evapotranspiration (ET) was reasonably 'conservative' over the studied LAI range 0.5-7.0 m(2) m(-2) . Both ET and Gs experienced a minimum in the LAI range 1-2 m(2) m(-2) caused by opposing nonproportional response of stomatally controlled transpiration and 'free' forest floor evaporation to changes in canopy density. The young forests had strongest coupling with the atmosphere while stomatal control of energy partitioning was strongest in relatively sparse (LAI ~2 m(2) m(-2) ) pine stands growing on mineral soils. The data analysis and model results suggest that LAI may be an effective scaling parameter for net radiation and its partitioning but only in sparse stands (LAI energy exchange. In denser forests, any LAI dependency varies with physiological traits such as light-saturated water-use efficiency. The results suggest that incorporating species traits and site conditions are necessary when LAI is used in upscaling energy exchanges of boreal coniferous forests.

  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. The research of air pollution based on spectral features in leaf surface of Ficus microcarpa in Guangzhou, China.

    Science.gov (United States)

    Wang, Jie; Xu, Ruisong; Ma, Yueliang; Miao, Li; Cai, Rui; Chen, Yu

    2008-07-01

    Nowadays development of industry and traffic are the main contributor to city air pollution in the city of GuangZhou, China. Conventional methods for investigating atmosphere potentially harmful element pollution based on sampling and chemical analysis are time and labor consuming and relatively expensive. Reflectance spectroscopy within the visible-near-infrared region of vegetation in city has been widely used to predict atmosphere constituents due to its rapidity, convenience and accuracy. The objective of this study was to examine the possibility of using leaves reflectance spectra of vegetation as a rapid method to simultaneously assess pollutant (S, Cd, Cu, Hg, Pb, XCl, XF) in the atmosphere of the Guangzhou area. This article has studied the spectral features of polluted leaf surface of Ficus microcarpa in 1985 and 1998. According to the analysis, comprehensive assessment for the change of atmospheric condition and degrees of pollution were given. This conclusion was confirmed by the monitored data got from chemical analysis. Future study with real remote sensing data and field measurements were strongly recommended.

  18. Superfície foliar da videira 'Folha de Figo' e 'Niagara Rosada' conduzida em diferentes sistemas de condução Surface leaf of the vine 'Leaf of Fig' and 'Rosy Niagara' grown in different culture systems

    Directory of Open Access Journals (Sweden)

    Paulo Márcio Norberto

    2008-12-01

    Full Text Available Os efeitos da interação entre a forma do dossel vegetal e os fatores ambientais locais resultam no microclima que determinará alguns aspectos fisiológicos da videira, podendo afetar significativamente o crescimento vegetativo da videira, a produtividade do vinhedo, bem como a qualidade da uva e do vinho. O trabalho foi desenvolvido na Estação de Viticultura e Enologia de Caldas EPAMIG, Caldas, MG, com o objetivo de avaliar o efeito do sistema de condução sobre a superfície foliar da videira (Vitis labrusca L., durante as safras 2003, 2004 e 2005. As variedades produtoras utilizadas no experimento foram 'Niágara Rosada' para mesa e 'Folha de Figo' para produção de vinhos; como porta - enxerto utilizou-se o '420-A'. O delineamento experimental foi DIC em fatorial 4x2 e os sistemas adotados foram cordão simples, latada, espaldeira e lira. Determinaram-se as seguintes variáveis: superfície foliar primária, secundária, total e superfície foliar exposta (SFE.Verificou-se que o sistema cordão simples conferiu a menor superfície foliar total em ambas as variedades, em todas safras avaliadas. Tanto o sistema espaldeira quanto o cordão simples conferiram à menor superfície foliar exposta em ambas as variedades e os sistemas latada e lira, os maiores valores de (SFE.The effects of the interaction between the form of the vegetable canopy and the environmental factors places result in the microclima that will determine some physiologic aspects of the vine, and may affect significantly the vegetative growth of the vine, the productivity of the vineyard, as well as the quality of the grape and wine. The work was developed in the Station of Viticulture and Enologia of Caldas EPAMIG, Caldas, MG, with the aim of evaluating the effect of the Training system on the foliar surface of the vine (Vitis labrusca L. during the crops 2003, 2004 and 2005. The producing varieties used in the experiment were ' Niágara Rosy' for table and ' Leaf of

  19. Long-chain alkanes and fatty acids from Ludwigia octovalvis weed leaf surface waxes as short-range attractant and ovipositional stimulant to Altica cyanea (Weber) (Coleoptera: Chrysomelidae).

    Science.gov (United States)

    Mitra, S; Sarkar, N; Barik, A

    2017-01-30

    The importance of leaf surface wax compounds from the rice-field weed Ludwigia octovalvis (Jacq.) Raven (Onagraceae) was determined in the flea beetle Altica cyanea (Weber) (Coleoptera: Chrysomelidae). Extraction, thin layer chromatography and GC-MS and GC-FID analyses of surface waxes of young, mature and senescent leaves revealed 20, 19 and 19 n-alkanes between n-C15 and n-C35, respectively; whereas 14, 14 and 12 free fatty acids between C12:0 and C22:0 fatty acids were identified in young, mature and senescent leaves, respectively. Tricosane was predominant n-alkane in young and mature leaves, whilst eicosane predominated in senescent leaves. Heneicosanoic acid, palmitic acid and docosanoic acid were the most abundant free fatty acids in young, mature and senescent leaves, respectively. A. cyanea females showed attraction to 0.25 mature leaf equivalent surface waxes compared with young or senescent leaves in a short glass Y-tube olfactometer bioassay. The insects were attracted to a synthetic blend of 0.90, 1.86, 1.83, 1.95, 0.50 and 0.18 µg ml-1 petroleum ether of hexadecane, octadecane, eicosane, tricosane, palmitic acid and alpha-linolenic acid, respectively, comparable with the proportions as present in 0.25 mature leaf equivalent surface waxes. A. cyanea also laid eggs on a filter paper moistened with 0.25 mature leaf equivalent surface waxes or a synthetic blend of 0.90, 1.86, 1.83, 1.95, 0.50 and 0.18 µg ml-1 petroleum ether of hexadecane, octadecane, eicosane, tricosane, palmitic acid and alpha-linolenic acid, respectively. This finding could provide a basis for monitoring of the potential biocontrol agent in the field.

  20. Summer (subarctic) versus winter (subtropic) production affects spinach (Spinacia oleracea L.) leaf bionutrients: vitamins (C, E, Folate, K1, provitamin A), lutein, phenolics, and antioxidants.

    Science.gov (United States)

    Lester, Gene E; Makus, Donald J; Hodges, D Mark; Jifon, John L

    2013-07-24

    Comparison of spinach (Spinacia oleracea L.) cultivars Lazio and Samish grown during the summer solstice in the subarctic versus the winter solstice in the subtropics provided insight into interactions between production environment (light intensity), cultivar, and leaf age/maturity/position affecting bionutrient concentrations of vitamins (C, E, folate, K1, provitamin A), lutein, phenolics, and antioxidants. Growing spinach during the winter solstice in the subtropics resulted in increased leaf dry matter %, oxidized (dehydro) ascorbic acid (AsA), α- and γ-tocopherol, and total phenols but lower reduced (free) AsA, α-carotene, folate, and antioxidant capacity compared to summer solstice-grown spinach in the subarctic. Both cultivars had similar bionutrients, except for higher dehydroAsA, and lower α- and γ-tocopherol in 'Samish' compared to 'Lazio'. For most bionutrients measured, there was a linear, and sometimes quadratic, increase in concentrations from bottom to top canopy leaves. However, total phenolics and antioxidant capacity increased basipetally. The current study has thus demonstrated that dehydroAsA, α-tocopherol, and γ-tocopherol were substantially lower in subarctic compared to subtropical-grown spinach, whereas the opposite relationship was found for antioxidant capacity, α-carotene, and folates (vitamin B9). The observations are consistent with previously reported isolated effects of growth environment on bionutrient status of crops. The current results clearly highlight the effect of production environment (predominantly radiation capture), interacting with genetics and plant phenology to alter the bionutrient status of crops. While reflecting the effects of changing growing conditions, these results also indicate potential alterations in the nutritive value of foods with anticipated shifts in global climatic conditions.

  1. Tomato yellow leaf curl virus infection of tomato does not affect the performance of the Q and ZHJ2 biotypes of the viral vector Bemisia tabaci

    Institute of Scientific and Technical Information of China (English)

    Meng Li; Jian Liu; Shu-Sheng Liu

    2011-01-01

    To better understand the etiology of begomovirus epidemics in regions under invasion we need to know how indigenous and invasive whitefly vectors respond to virus infection.We investigated both direct and indirect effects of infection with Tomato yellow leaf curl virus(TYLCV)on the performance of the invasive Q biotype and the indigenous Asian ZHJ2 biotype of whitefly Bemisia tabaci.The Q biotype performed better than the ZHJ2 biotype on either uninfected or virus-infected tomato plants.However,virus-infection of host plants did not,or only marginally affected,the performance of either biotype of whiteflies m terms of fecundity,longevity,survival,development and population increase.Likewise,association of the vectors with TYLCV did not affect fecundity and longevity of the Q or ZHJ2 biotypes on cotton,a non-host of TYLCV.These results indicate that the alien Q biotype whitefly,but not the indigenous ZHJ2 biotype,is likely to become the major vector of TYLCV in the field and facilitate virus epidemics.

  2. Surface physicochemistry and ionic strength affects eDNA's role in bacterial adhesion to abiotic surfaces

    DEFF Research Database (Denmark)

    Regina, Viduthalai R.; Lokanathan, Arcot R.; Modrzynski, Jakub Jan;

    2014-01-01

    DNA-mediated adhesion depends on the physicochemical properties of the surface and surrounding liquid. We investigated eDNA alteration of cell surface hydrophobicity and zeta potential, and subsequently quantified the effect of eDNA on the adhesion of Staphylococcus xylosus to glass surfaces functionalised...... ionic strengths. No effect was seen on glass surfaces and carboxyl-functionalised surfaces at high ionic strength, and a reverse effect occurred on amine-functionalised surfaces at low ionic strength. However, eDNA promoted adhesion of cells to hydrophobic surfaces irrespective of the ionic strength...... with different chemistries resulting in variable hydrophobicity and charge. Cell adhesion experiments were carried out at three different ionic strengths. Removal of eDNA from S. xylosus cells by DNase treatment did not alter the zeta potential, but rendered the cells more hydrophilic. DNase treatment impaired...

  3. Acetylation of cell wall is required for structural integrity of the leaf surface and exerts a global impact on plant stress responses

    DEFF Research Database (Denmark)

    Nafisi, Majse; Stranne, Maria; Fimognari, Lorenzo;

    2015-01-01

    -dense deposits. A large number of trichomes were collapsed and surface permeability of the leaves was enhanced in rwa2 as compared to the wild type. A massive reprogramming of the transcriptome was observed in rwa2 as compared to the wild type, including a coordinated up-regulation of genes involved in responses...... acetylation is essential for maintaining the structural integrity of leaf epidermis, and that reduction of cell wall acetylation leads to global stress responses in Arabidopsis....

  4. Assimilation of leaf area index and surface soil moisture satellite observations into the SIM hydrological model over France

    Science.gov (United States)

    Fairbairn, David; Calvet, Jean-Christophe; Mahfouf, Jean-Francois; Barbu, Alina

    2016-04-01

    Hydrological models have a variety of uses, including flood and drought prediction and water management. The SAFRAN-ISBA-MODCOU (SIM) hydrological model consists of three stages: An atmospheric analysis (SAFRAN) over France, which forces a land surface model (ISBA-A-gs), which then provides drainage and runoff inputs to a hydrological model (MODCOU). The river discharge from MODCOU is validated using observed river discharge over France. Data assimilation (DA) combines a short model forecast from the past with observations to improve the estimate of the model state. The ISBA-A-gs representation of soil moisture and its influence by vegetation can be improved by assimilating surface soil moisture (SSM) and leaf area index (LAI) observations respectively. The Advanced Scatterometer (ASCAT) on board the MetOP satellite measures a low-frequency microwave signal, which is used to retrieve daily SSM over France. The SPOT-VGT sensor observes LAI over France at a temporal frequency of about 10 days. The Simplified Extended Kalman (SEKF) filter combines the model and observed variables by weighting them according to their respective accuracies. Although the SEKF makes incorrect linear assumptions, past experiments have shown that it improves on the model estimates of SSM and LAI. However, due to nonlinearities in the land surface model, improvements in SSM and LAI do not imply improved soil moisture fluxes (drainage, runoff and evapotranspiration). This study indirectly examines the impact of the SEKF on the soil moisture fluxes using the MODCOU hydrological model. The ISBA-A-gs model appears to underestimate the LAI for grasslands in winter and spring, which results in an underestimation (overestimation) of evapotranspiration (drainage and runoff). The excess water flowing into the rivers and aquifers contributes to an overestimation of the MODCOU discharge. Assimilating LAI observations slightly increases the LAI analysis in winter and spring and therefore reduces the

  5. Surface physicochemistry and ionic strength affects eDNA's role in bacterial adhesion to abiotic surfaces.

    Directory of Open Access Journals (Sweden)

    Viduthalai R Regina

    Full Text Available Extracellular DNA (eDNA is an important structural component of biofilms formed by many bacteria, but few reports have focused on its role in initial cell adhesion. The aim of this study was to investigate the role of eDNA in bacterial adhesion to abiotic surfaces, and determine to which extent eDNA-mediated adhesion depends on the physicochemical properties of the surface and surrounding liquid. We investigated eDNA alteration of cell surface hydrophobicity and zeta potential, and subsequently quantified the effect of eDNA on the adhesion of Staphylococcus xylosus to glass surfaces functionalised with different chemistries resulting in variable hydrophobicity and charge. Cell adhesion experiments were carried out at three different ionic strengths. Removal of eDNA from S. xylosus cells by DNase treatment did not alter the zeta potential, but rendered the cells more hydrophilic. DNase treatment impaired adhesion of cells to glass surfaces, but the adhesive properties of S. xylosus were regained within 30 minutes if DNase was not continuously present, implying a continuous release of eDNA in the culture. Removal of eDNA lowered the adhesion of S. xylosus to all surfaces chemistries tested, but not at all ionic strengths. No effect was seen on glass surfaces and carboxyl-functionalised surfaces at high ionic strength, and a reverse effect occurred on amine-functionalised surfaces at low ionic strength. However, eDNA promoted adhesion of cells to hydrophobic surfaces irrespective of the ionic strength. The adhesive properties of eDNA in mediating initial adhesion of S. xylosus is thus highly versatile, but also dependent on the physicochemical properties of the surface and ionic strength of the surrounding medium.

  6. Model of leaf energy distribution and its experimental validation of Populus tomentosa Carr

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wen-jie; WANG Min; SHEN Ying-bai; ZHANG Zhi-yi

    2008-01-01

    Leaf temperature of a plant is the result of heat transfer between the plant and its environment. There are many factors that can affect leaf temperature, such as the solar radiation energy, environmental temperature, wind velocity, evaporation on the leaf surface, photosynthesis, respiration and so on, which have different effects on the temperature of leaves. In first instance, we analyzed the heat transfer on leaves of Populus tomentosa Cart. theoretically and constructed a model of energy distribution. We then validated the model by analyzing seven different kinds of one-year-old P. tomentosa leaves experimentally. The result shows that solar radiation is the main energy input and the dominant ways of thermal diffusion are heat transfer between the upper and lower leaf surfaces and evaporation from the leaf surface.

  7. Extraction of bioactive compounds and free radical scavenging activity of purple basil (Ocimum basilicum L.) leaf extracts as affected by temperature and time.

    Science.gov (United States)

    Pedro, Alessandra C; Moreira, Fernanda; Granato, Daniel; Rosso, Neiva D

    2016-05-13

    In the current study, response surface methodology (RSM) was used to assess the effects of extraction time and temperature on the content of bioactive compounds and antioxidant activity of purple basil leaf (Ocimum basilicum L.) extracts. The stability of anthocyanins in relation to temperature, light and copigmentation was also studied. The highest anthocyanin content was 67.40 mg/100 g extracted at 30 °C and 60 min. The degradation of anthocyanins with varying temperatures and in the presence of light followed a first-order kinetics and the activation energy was 44.95 kJ/mol. All the extracts exposed to light showed similar half-lives. The extracts protected from light, in the presence of copigments, showed an increase in half-life from 152.67 h for the control to 856.49 and 923.17 h for extract in the presence of gallic acid and phytic acid, respectively. These results clearly indicate that purple basil is a potential source of stable bioactive compounds.

  8. Extraction of bioactive compounds and free radical scavenging activity of purple basil (Ocimum basilicum L. leaf extracts as affected by temperature and time

    Directory of Open Access Journals (Sweden)

    ALESSANDRA C. PEDRO

    2016-06-01

    Full Text Available In the current study, response surface methodology (RSM was used to assess the effects of extraction time and temperature on the content of bioactive compounds and antioxidant activity of purple basil leaf (Ocimum basilicum L. extracts. The stability of anthocyanins in relation to temperature, light and copigmentation was also studied. The highest anthocyanin content was 67.40 mg/100 g extracted at 30 °C and 60 min. The degradation of anthocyanins with varying temperatures and in the presence of light followed a first-order kinetics and the activation energy was 44.95 kJ/mol. All the extracts exposed to light showed similar half-lives. The extracts protected from light, in the presence of copigments, showed an increase in half-life from 152.67 h for the control to 856.49 and 923.17 h for extract in the presence of gallic acid and phytic acid, respectively. These results clearly indicate that purple basil is a potential source of stable bioactive compounds.

  9. Superhydrophobicity of Lotus-leaf-like Fluorinated Ethylene Propylene Copolymer Surface%类荷叶结构聚全氟乙丙烯的超疏水性

    Institute of Scientific and Technical Information of China (English)

    刘传生; 蒋文曲; 管自生

    2011-01-01

    Superhydrophobic fluorinated ethylene propylene (FEP) copolymer surface with lotus-leaf-like structure was prepared by thermoforming FEP powder at the condition of 0.3 N/cm2, 280 ℃ and - O. 1 MPa vacuum on the polydimethylsiloxane(PDMS) templates, which replicated the lotus leaf surface. The SEM results indicate that the FEP surface shows great similar lotus-leaf-like structures with superhydrophobic, corresponding water contact angle and tilt angle are ( 168 ± 1 )° andd 2°, respectively. The superhydrophobic lotusleaf-like FEP surface also exhibits good stability in water, acohol, acid and alkaline solution after duration of 10 h immersion. Furthermore, once the hydrophobicity of FEP surface decreased, it is recoverable via an immersion process in piranha solution for 10 min. Differential scanning calorimetry( DSC ) results indicate the mass loss of the PDMS templates is very low, which means it can be used repeatedly during the thermoforming process. Therefore, the methods combine the very good acid resistant, alkaline resistant and corrosion resistant of the FEP with lotus-leaf-like structure to fabrication of superhydropobic surface may be applied in preparation of anti-adhension and serf-cleaning vessels, etc.%以聚二甲基硅氧烷(PDMS)复制的荷叶表面微结构为阴模模板,将聚全氟乙丙烯(FEP)粉体置于该阴模模板上,在压力约为0.3 N/cm,280℃和-0.1 MPa真空条件下,热压成型,制备了具有类荷叶结构的FEP表面.扫描电镜观察结果表明,FEP表面与荷叶表面微结构具有很大的相似性,该表面具有良好的超疏水性,与水的接触角达到(168±1)°,滚动角约为2°,而且具有良好的疏酸、疏碱、疏盐性能和稳定性,即使在溶液中长期浸泡而失去超疏水性能后,经Piranha洗液(体积分数为70%的浓硫酸和30%的HO)处理约10 min,其表面疏水、疏酸和疏碱性能可迅速恢复.热重分析结果表明,PDMS阴模在热压条件下失重极小,可重复使用.

  10. How subsurface patterns affect surface energy budget patterns: a sudanian case study

    Science.gov (United States)

    Robert, D.; Cohard, J.; Descloitres, M.; Vandervaere, J.; Braud, I.; Vauclin, M.

    2011-12-01

    Fractured bedrock areas are still challenging for hydrological modeling because of their complex underground property distributions. The heterogeneity in soil hydraulic properties, for example, can control the subsurface water fluxes and create surface soil moisture pattern which becomes preferential areas for runoff production or evapotranspiration. This study aimed to evaluate the impact of a bedrock topography, including outcropping, on subsurface water fluxes and the induced energy budget patterns at the surface. To deal with these ground water/surface water interactions, we run the Parflow-CLM distributed coupled land surface and groundwater model over the 12km2 Ara watershed (Northern Benin) for different bedrock configurations. The Ara catchment is submitted to a sudanian climate with 1200mm total rainfall per year. It is part of the AMMA-Catch project in which 3 meso sites have been documented along a south to north transect in West Africa. The geology of the Ara catchment is composed of metamorphic rocks. The main orientation of the geological structures (and of the gneiss foliation) is roughly north-south and the dip angle is 20° east. These structure create patterns in effective porosity distribution which is supposed to induce subsurface flow perpendicular to surface slope direction. Controlled Parflow-CLM simulation results are compared with energy budget data, including 3 net radiation measurements, eddy covariance station, scintillometric measurements to estimate evapotranspiration at different scales. The experimental device also include ground measurements like distributed surface soil moisture profile and piezometers. Parflow-CLM simulations are in good agreement with energy budget observations if observed Leaf Area Index time series are take into account. Then different hydraulic property distributions (effective porosity, hydraulic transmissivity, water retention curves) are evaluated through watershed dynamic differences.

  11. Does the Economy or Surface Warfare Officer Career Pay Affect Surface Warfare Officer Retention?

    Science.gov (United States)

    2014-12-01

    Table 13.  OLS coefficients and T-stat for female data set .................................. 35  Table 14.  Summary of expected and observed...retention to the economy, SWO career pay (SWOCP), and an interaction of the economy and SWOCP. B. EXPECTED BENEFITS A better understanding of...insufficient evidence to support H2, that career pay positively affects the female SWO population. 36 (3) Female Data Set—H3 The female data set is

  12. How will surface treatments affect the translucency of porcelain laminate veneers?

    OpenAIRE

    Turgut, Sedanur; Bagis, Bora; Ayaz, Elif Aydogan; Korkmaz, Fatih Mehmet; Ulusoy, Kıvanç Utku; Bagis, Yildirim Hakan

    2014-01-01

    PURPOSE The purpose of this study was to evaluate whether surface treatments affect the translucency of laminate veneers with different shades and thicknesses. MATERIALS AND METHODS A total of 224 disc-shaped ceramic veneers were prepared from A1, A3, HT (High Translucent) and HO (High Opaque) shades of IPS e.max Press (Ivoclar Vivadent) with 0.5 mm and 1.0 mm thicknesses. The ceramics were divided into four groups for surface treatments. Group C: no surface treatments; Group HF: etched with ...

  13. Interactions of bluff-body obstacles with turbulent airflows affecting evaporative fluxes from porous surfaces

    Science.gov (United States)

    Haghighi, Erfan; Or, Dani

    2015-11-01

    Bluff-body obstacles interacting with turbulent airflows are common in many natural and engineering applications (from desert pavement and shrubs over natural surfaces to cylindrical elements in compact heat exchangers). Even with obstacles of simple geometry, their interactions within turbulent airflows result in a complex and unsteady flow field that affects surface drag partitioning and transport of scalars from adjacent evaporating surfaces. Observations of spatio-temporal thermal patterns on evaporating porous surfaces adjacent to bluff-body obstacles depict well-defined and persistent zonation of evaporation rates that were used to construct a simple mechanistic model for surface-turbulence interactions. Results from evaporative drying of sand surfaces with isolated cylindrical elements (bluff bodies) subjected to constant turbulent airflows were in good agreement with model predictions for localized exchange rates. Experimental and theoretical results show persistent enhancement of evaporative fluxes from bluff-rough surfaces relative to smooth flat surfaces under similar conditions. The enhancement is attributed to formation of vortices that induce a thinner boundary layer over part of the interacting surface footprint. For a practical range of air velocities (0.5-4.0 m/s), low-aspect ratio cylindrical bluff elements placed on evaporating sand surfaces enhanced evaporative mass losses (relative to a flat surface) by up to 300% for high density of elements and high wind velocity, similar to observations reported in the literature. Concepts from drag partitioning were used to generalize the model and upscale predictions to evaporation from surfaces with multiple obstacles for potential applications to natural bluff-rough surfaces.

  14. 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

  15. Nanoscale topographic changes on sterilized glass surfaces affect cell adhesion and spreading.

    Science.gov (United States)

    Wittenburg, Gretel; Lauer, Günter; Oswald, Steffen; Labudde, Dirk; Franz, Clemens M

    2014-08-01

    Producing sterile glass surfaces is of great importance for a wide range of laboratory and medical applications, including in vitro cell culture and tissue engineering. However, sterilization may change the surface properties of glass and thereby affect its use for medical applications, for instance as a substrate for culturing cells. To investigate potential effects of sterilization on glass surface topography, borosilicate glass coverslips were left untreated or subjected to several common sterilization procedures, including low-temperature plasma gas, gamma irradiation and steam. Imaging by atomic force microscopy demonstrated that the surface of untreated borosilicate coverslips features a complex landscape of microislands ranging from 1000 to 3000 nm in diameter and 1 to 3 nm in height. Steam treatment completely removes these microislands, producing a nanosmooth glass surface. In contrast, plasma treatment partially degrades the microisland structure, while gamma irradiation has no effect on microisland topography. To test for possible effects of the nanotopographic structures on cell adhesion, human gingival fibroblasts were seeded on untreated or sterilized glass surfaces. Analyzing fibroblast adhesion 3, 6, and 24 h after cell seeding revealed significant differences in cell attachment and spreading depending on the sterilization method applied. Furthermore, single-cell force spectroscopy revealed a connection between the nanotopographic landscape of glass and the formation of cellular adhesion forces, indicating that fibroblasts generally adhere weakly to nanosmooth but strongly to nanorough glass surfaces. Nanotopographic changes induced by different sterilization methods may therefore need to be considered when preparing sterile glass surfaces for cell culture or biomedical applications.

  16. Towards understanding how surface life can affect interior geological processes: a non-equilibrium thermodynamics approach

    Directory of Open Access Journals (Sweden)

    J. G. Dyke

    2011-06-01

    Full Text Available Life has significantly altered the Earth's atmosphere, oceans and crust. To what extent has it also affected interior geological processes? To address this question, three models of geological processes are formulated: mantle convection, continental crust uplift and erosion and oceanic crust recycling. These processes are characterised as non-equilibrium thermodynamic systems. Their states of disequilibrium are maintained by the power generated from the dissipation of energy from the interior of the Earth. Altering the thickness of continental crust via weathering and erosion affects the upper mantle temperature which leads to changes in rates of oceanic crust recycling and consequently rates of outgassing of carbon dioxide into the atmosphere. Estimates for the power generated by various elements in the Earth system are shown. This includes, inter alia, surface life generation of 264 TW of power, much greater than those of geological processes such as mantle convection at 12 TW. This high power results from life's ability to harvest energy directly from the sun. Life need only utilise a small fraction of the generated free chemical energy for geochemical transformations at the surface, such as affecting rates of weathering and erosion of continental rocks, in order to affect interior, geological processes. Consequently when assessing the effects of life on Earth, and potentially any planet with a significant biosphere, dynamical models may be required that better capture the coupled nature of biologically-mediated surface and interior processes.

  17. Inferring Amazon leaf demography from satellite observations of leaf area index

    Directory of Open Access Journals (Sweden)

    S. Caldararu

    2012-04-01

    Full Text Available Seasonal and year-to-year variations in leaf cover imprint significant spatial and temporal variability on biogeochemical cycles, and affect land-surface properties related to climate. We develop a demographic model of leaf phenology based on the hypothesis that trees seek an optimal leaf area index (LAI as a function of available light and soil water, and fit it to spaceborne observations of LAI over the Amazon basin, 2001–2005. We find the model reproduces the spatial and temporal LAI distribution whilst also predicting geographic variation in leaf age from the basin centre (2.1 ± 0.2 years, through to the lowest values over the deciduous eastern and southern Amazon (6 ± 2 months. The model explains the observed increase in LAI during the dry season as a net addition of leaves in response to increased solar radiation. We anticipate our work to be a starting point from which to develop better descriptions of leaf phenology to incorporate into more sophisticated earth system models.

  18. Inferring Amazon leaf demography from satellite observations of leaf area index

    Directory of Open Access Journals (Sweden)

    S. Caldararu

    2011-10-01

    Full Text Available Seasonal and year-to-year variations in leaf cover imprint significant spatial and temporal variability on biogeochemical cycles, and affect land-surface properties related to climate. We develop a demographic model of leaf phenology based on the hypothesis that trees seek an optimal Leaf Area Index (LAI as a function of available light and soil water, and fitted it to spaceborne observations of LAI over the Amazon Basin, 2001–2005. We find the model reproduces the spatial and temporal LAI distribution whilst also predicting geographic variation in leaf age from the basin center (2.1 ± 0.2 yr, through to the lowest values over the deciduous Eastern Amazon (6 ± 2 months. The model explains the observed increase in LAI during the dry season as a net addition of leaves in response to increased solar radiation. We anticipate our work to be a starting point from which to develop better descriptions of leaf phenology to incorporate into more sophisticated earth system models.

  19. Assimilation of Soil Wetness Index and Leaf Area Index into the ISBA-A-gs land surface model: grassland case study

    Directory of Open Access Journals (Sweden)

    A. L. Barbu

    2011-02-01

    Full Text Available The performance of the joint assimilation in a land surface model of a Soil Wetness Index (SWI product provided by an exponential filter together with Leaf Area Index (LAI is investigated. The data assimilation is evaluated with different setups using the SURFEX modeling platform, for a period of seven years (2001–2007, at the SMOSREX grassland site in southwestern France. The results obtained with a Simplified Extended Kalman Filter demonstrate the effectiveness of a joint data assimilation scheme when both SWI and Leaf Area Index are merged into the ISBA-A-gs land surface model. The assimilation of a retrieved Soil Wetness Index product presents several challenges that are investigated in this study. A significant improvement of around 13% of the root-zone soil water content is obtained by assimilating dimensionless root-zone SWI data. For comparison, the assimilation of in situ surface soil moisture is considered as well. A lower impact on the root zone is noticed. Under specific conditions, the transfer of the information from the surface to the root zone was found not accurate. Also, our results indicate that the assimilation of in situ LAI data may correct a number of deficiencies in the model, such as low LAI values in the senescence phase by using a seasonal-dependent error definition for background and observations. In order to verify the specification of the errors for SWI and LAI products, a posteriori diagnostics are employed. This approach highlights the importance of the assimilation design on the quality of the analysis. The impact of data assimilation scheme on CO2 fluxes is also quantified by using measurements of net CO2 fluxes gathered at the SMOSREX site from 2005 to 2007. An improvement of about 5% in terms of rms error is obtained.

  20. Do Aging and Tactile Noise Stimulation Affect Responses to Support Surface Translations in Healthy Adults?

    Directory of Open Access Journals (Sweden)

    Marius Dettmer

    2016-01-01

    Full Text Available Appropriate neuromuscular responses to support surface perturbations are crucial to prevent falls, but aging-related anatomical and physiological changes affect the appropriateness and efficiency of such responses. Low-level noise application to sensory receptors has shown to be effective for postural improvement in a variety of different balance tasks, but it is unknown whether this intervention may have value for improvement of corrective postural responses. Ten healthy younger and ten healthy older adults were exposed to sudden backward translations of the support surface. Low-level noise (mechanical vibration to the foot soles was added during random trials and temporal (response latency and spatial characteristics (maximum center-of-pressure excursion and anterior-posterior path length of postural responses were assessed. Mixed-model ANOVA was applied for analysis of postural response differences based on age and vibration condition. Age affected postural response characteristics, but older adults were well able to maintain balance when exposed to a postural perturbation. Low-level noise application did not affect any postural outcomes. Healthy aging affects some specific measures of postural stability, and in high-functioning older individuals, a low-level noise intervention may not be valuable. More research is needed to investigate if recurring fallers and neuropathy patients could benefit from the intervention in postural perturbation tasks.

  1. Plasma treatment of polystyrene thin films affects more than the surface.

    Science.gov (United States)

    Calchera, Angela R; Curtis, Alexander D; Patterson, James E

    2012-07-25

    Plasma treatment of polymer materials introduces chemical functionalities and modifies the material to make the native hydrophobic surface more hydrophilic. It is generally assumed that this process only affects the surface of the material. We used vibrationally resonant sum-frequency generation spectroscopy to observe changes in the orientation of phenyl groups in polystyrene (PS) thin films on various substrates before and after plasma treatment. VR-SFG selectively probes regions of broken symmetry, such as surfaces, but can also detect the emergence of anisotropy. On dielectric substrates, such as fused silica, the spectroscopic peak corresponding to the symmetric stretching (ν2) mode of the phenyl rings was undetectable after plasma treatment, showing that surface phenyl rings were altered. This peak also diminished on conducting substrates, but the intensity of another peak corresponding to the same mode in a bulklike environment increased significantly, suggesting that plasma treatment induces partial ordering of the bulk polymer. This ordering is seen on conducting substrates even when the polymer is not directly exposed to the plasma. Annealing reverses these effects on the polystyrene bulk; however, the surface phenyl rings do not return to the orientation observed for untreated films. These results call into question the assumption that the effects of plasma treatment are limited to the free surface and opens up other possibilities for material modification with low-temperature plasmas.

  2. Relationship Between Leaf C/N Ratio and Insecticidal Protein Expression in Bt Cotton as Affected by High Temperature and N Rate

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiang; LÜ Chun-hua; CHEN Yuan; WANG Gui-xia; CHEN Yuan; CHEN De-hua

    2014-01-01

    Expression of insecticidal protein for transgenic Bacillus thuringiensis (Bt) cotton is unstable and related to nitrogen metabolism. The objective of this study was to investigate the relationship between leaf carbon nitrogen ratio (C/N) and insecticidal efifcacy of two Bt cotton cultivars. C/N ratio and Bt protein content were both measured at peak square period and peak boll period respectively under 5-7 d high temperature and different nitrogen fertilizer rates on the Yangzhou University Farm and the Ludong Cotton Farm, China. All plants were grown in ifeld. The results showed that the C/N ratio enhanced slightly and the Bt protein content remained stable at peak square period, but significant increases for the C/N ratio and decreases markedly for the leaf Bt protein concentration were detected at the peak boll period. The similar patterns at the two growth periods were found for the leaf C/N ratio and Bt protein content by different N fertilizer treatments. When nitrogen rate was from 0 to 600 kg ha-1, the C/N ratio was reduced by 0.017 and 0.006 for Sikang 1 and Sikang 3 at peak square period, compared to the 1.350 to 1.143 reduction for Sikang 1 and Sikang 3 at peak boll period, respectively. Correspondingly, the leaf Bt protein contents were bolstered by 2.6-11.8 and 26.9-36.9% at the two different growth periods, respectively. The results suggested that enhanced C/N ratio by high temperature and nitrogen application may result in the reduction of insectiocidal efifcacy in Bt cotton, especially in peak boll period.

  3. Connecting the dots - III. Nightside cooling and surface friction affect climates of tidally locked terrestrial planets

    Science.gov (United States)

    Carone, L.; Keppens, R.; Decin, L.

    2016-09-01

    We investigate how nightside cooling and surface friction affect surface temperatures and large-scale circulation for tidally locked Earth-like planets. For each scenario, we vary the orbital period between Prot = 1 and 100 d and capture changes in climate states. We find drastic changes in climate states for different surface friction scenarios. For very efficient surface friction (ts,fric = 0.1 d), the simulations for short rotation periods (Prot ≤ 10 d) show predominantly standing extratropical Rossby waves. These waves lead to climate states with two high-latitude westerly jets and unperturbed meridional direct circulation. In most other scenarios, simulations with short rotation periods exhibit instead dominance by standing tropical Rossby waves. Such climate states have a single equatorial westerly jet, which disrupts direct circulation. Experiments with weak surface friction (ts,fric = 10-100 d) show decoupling between surface temperatures and circulation, which leads to strong cooling of the nightside. The experiment with ts,fric = 100 d assumes climate states with easterly flow (retrograde rotation) for medium and slow planetary rotations Prot = 12-100 d. We show that an increase of nightside cooling efficiency by one order of magnitude compared to the nominal model leads to a cooling of the nightside surface temperatures by 80-100 K. The dayside surface temperatures only drop by 25 K at the same time. The increase in thermal forcing suppresses the formation of extratropical Rossby waves on small planets (RP = 1REarth) in the short rotation period regime (Prot ≤ 10 d).

  4. Topographical changes of ground surface affected by the Tarim Desert Highway

    Institute of Scientific and Technical Information of China (English)

    LI Shengyu; LEI Jiaqiang; XU Xinwen; WANG Lixin; ZHOU Zhibin; LI Hongzhong

    2006-01-01

    The Tarim Desert Highway is the longest highway crossing the mobile desert in the world. The highway and its sand protection system were established in 1995. This great project must have significant effect on the aeolian environment in its neighborhoods. In 2004, we investigated the topographic changes of ground surface within the sand protection system and its external adjacent area in the hinterland of the Taklimakan Desert. The results showed that (i) the original topographic patterns of ground surface were greatly changed, and erosion as well as deposition was distributed clearly on the ground surface, affected by the road and its sand protection system; (ii) sediment deposited in the sand protection system gradually heightened the ground surface, but each part in the system changed differently: in the sand-blocking belt, a transverse sand ridge was formed in the same direction as the upright sand barrier; in the sand-binding belt, sediment was aggraded on the original surface in a certain thickness; at the initial stages since the establishment of the sand protection system, erosion had taken place in the un-stabilized area named by the deposition belt between the sand-blocking belt and the sand-binding belt, the inner of sand-binding belt, the windward slope of dunes in the sand-binding belt, and the neighboring leeward area of the sand protection system.

  5. Dependence of leaf surface potential response of a plant (Ficus Elastica) to light irradiation on room temperature; Shokubutsu (gomunoki) hamen den`i no hikari shosha oto no shitsuon izonsei

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, H.; Kenmoku, Y.; Sakakibara, T. [Toyohashi University of Technology, Aichi (Japan); Nakagawa, S. [Maizuru National College of Technology, Kyoto (Japan); Kawamoto, T. [Shizuoka University, Shizuoka (Japan)

    1997-11-25

    In order to clarify plant body potential information, study was made on a leaf surface potential response to light irradiation. The leaf surface potential change, total transpiration and transpiration rate of Ficus Elastica were measured using light irradiation period and room temperature as parameters. The leaf surface potential change shows a positive peak after the start of light irradiation, while a negative peak after its end. Arrival time to both peaks is constant regardless of the light irradiation period, while decrease with an increase in room temperature. Although the total transpiration increases with room temperature, this tendency disappears with an increase in light irradiation period. The transpiration rate shows its peak after the start of light irradiation. Arrival time to the peak is saturated with the light irradiation period of 60min, while decreases with an increase in room temperature. These results suggest that opening of stomata becomes active with an increase in room temperature, and the peak of the leaf surface potential after the start of light irradiation relates to the opening. 3 refs., 11 figs.

  6. Genealogy and fine mapping of obscuravenosa, a gene affecting the distribution of chloroplasts in leaf veins, and evidence of selection during breeding of tomatoes (Lycopersicon esculentum; Solanaceae).

    Science.gov (United States)

    Jones, Carl M; Rick, Charles M; Adams, Dawn; Jernstedt, Judy; Chetelat, Roger T

    2007-06-01

    In the processes of plant domestication and variety development, some traits are under direct selection, while others may be introduced by indirect selection or linkage. In the cultivated tomato (Lycopersicon esculentum = Solanum lycopersicum), and all other Solanaceae examined, chloroplasts are normally absent from subepidermal and mesophyll cells surrounding the leaf veins, and thus, veins appear clear upon subillumination. The tomato mutant obscuravenosa (obv), in contrast, contains chloroplasts in cells around the vein, and thus, veins appear as dark as the surrounding leaf tissue. Among tomato cultivars, the obv allele is common in processing varieties bred for mechanical harvest, but is otherwise rare. We traced the source of obv in processing tomatoes to the cultivar Earliana, released in the 1920s. The obv locus was mapped to chromosome 5, bin 5G, using introgression lines containing single chromosome segments from the wild species L. pennellii. This region also contains a quantitative trait locus (QTL) for plant height, pht5.4, which cosegregated with SP5G, a paralog of self-pruning (sp), the gene that controls the switch between determinate and indeterminate growth in tomato. The pht5.4 QTL was partially dominant and associated with a reduced percentage of red fruit at harvest. Our data suggest that the prevalence of obv in nearly all processing varieties may have resulted from its tight linkage to a QTL conferring a more compact, and horticulturally desirable, plant habit.

  7. Leaf age affects the quality of DNA extracted from Dimorphandra mollis (Fabaceae), a tropical tree species from the Cerrado region of Brazil.

    Science.gov (United States)

    Moreira, P A; Oliveira, D A

    2011-03-01

    Isolation of high-quality DNA from plants, especially plants from the Cerrado, is notoriously difficult because of polysaccharides and secondary compounds produced by plants from this biome. DNA isolation and its quality may be compromised by chemical defenses such as tannins and phenols. Quantitative plant defenses tend to have a cumulative effect, increasing in concentration during leaf development, reducing DNA quality extracted in mature compared to young leaves. We report the effect of leaf age on DNA extraction of Dimorphandra mollis. Our working hypothesis was that the young leaves have more DNA than old leaves of the same individual because chemical defenses accumulate in older leaves. Young and old leaves were sampled from eight mature trees as well as leaves from eight seedlings in the north region of Minas Gerais State. Genomic DNA extraction followed the standard CTAB procedure. DNA isolation was very successful from young leaves of 16 individuals of D. mollis. The extracted DNA exhibited high quality and the DNA quantity was also high, with an A(260)/A(280) ratio above 1.8, which is within the optimal sample range. In contrast, DNA isolation from old leaves was not successful. When the DNA was extracted from old leaves, the DNA was brownish, indicating contamination by phenolic compounds. These metabolites oxidize the DNA irreversibly, which hinders amplification of DNA by PCR by inhibiting the action of enzymes such as Taq polymerase. PCR performed with DNA from young leaves of D. mollis was successful and produced strong bands for RAPD markers.

  8. Seasonal Influences on Ground-Surface Water Interactions in an Arsenic-Affected Aquifer in Cambodia

    Science.gov (United States)

    Richards, L. A.; Magnone, D.; Van Dongen, B.; Bryant, C.; Boyce, A.; Ballentine, C. J.; Polya, D. A.

    2015-12-01

    Millions of people in South and Southeast Asia consume drinking water daily which contains dangerous levels of arsenic exceeding health-based recommendations [1]. A key control on arsenic mobilization in aquifers in these areas has been controversially identified as the interaction of 'labile' organic matter contained in surface waters with groundwaters and sediments at depth [2-4], which may trigger the release of arsenic from the solid- to aqueous-phase via reductive dissolution of iron-(hyr)oxide minerals [5]. In a field site in Kandal Province, Cambodia, which is an arsenic-affected area typical to others in the region, there are strong seasonal patterns in groundwater flow direction, which are closely related to monsoonal rains [6] and may contribute to arsenic release in this aquifer. The aim of this study is to explore the implications of the high susceptibility of this aquifer system to seasonal changes on potential ground-surface water interactions. The main objectives are to (i) identify key zones where there are likely ground-surface water interactions, (ii) assess the seasonal impact of such interactions and (iii) quantify the influence of interactions using geochemical parameters (such as As, Fe, NO3, NH4, 14C, 3T/3He, δ18O, δ2H). Identifying the zones, magnitude and seasonal influence of ground-surface water interactions elucidates new information regarding potential locations/pathways of arsenic mobilization and/or transport in affected aquifers and may be important for water management strategies in affected areas. This research is supported by NERC (NE/J023833/1) to DP, BvD and CJB and a NERC PhD studentship (NE/L501591/1) to DM. References: [1] World Health Organization, 2008. [2] Charlet & Polya (2006), Elements, 2, 91-96. [3] Harvey et al. (2002), Science, 298, 1602-1606. [4] Lawson et al. (2013), Env. Sci. Technol. 47, 7085 - 7094. [5] Islam et al. (2004), Nature, 430, 68-71. [6] Benner et al. (2008) Appl. Geochem. 23(11), 3072 - 3087.

  9. Occurrence of perchloroethylene in surface water and fish in a river ecosystem affected by groundwater contamination.

    Science.gov (United States)

    Wittlingerová, Zdena; Macháčková, Jiřina; Petruželková, Anna; Zimová, Magdalena

    2016-03-01

    Long-term monitoring of the content of perchloroethylene (PCE) in a river ecosystem affected by groundwater contamination was performed at a site in the Czech Republic. The quality of surface water was monitored quarterly between 1994 and 2013, and fish were collected from the affected ecosystem to analyse the content of PCE in their tissue in 1998, 2011 and 2012. Concentrations of PCE (9-140 μg/kg) in the tissue of fish collected from the contaminated part of the river were elevated compared to the part of the river unaffected by the contamination (ND to 5 μg/kg PCE). The quality of surface water has improved as a result of groundwater remediation during the evaluated period. Before the remedial action, PCE concentrations ranged from 30 to 95 μg/L (1994-1997). Following commencement of remedial activities in September 1997, a decrease in the content of PCE in the surface water to 7.3 μg/L (1998) and further to 1 μg/L (2011) and 1.1 μg/L (2012) led to a progressive decrease in the average concentration of PCE in the fish muscle tissue from 79 μg/kg (1998) to 24 (2011) and 30 μg/kg (2012), respectively. It was determined that the bioconcentration of PCE does not have a linear dependence because the decrease in contamination in the fish muscle tissue is not directly proportional to the decrease in contamination in the river water. The observed average bioconcentration factors were 24 and 28 for the lower concentrations of PCE and 11 for the higher concentrations of PCE in the river. In terms of age, length and weight of the collected fish, weight had the greatest significance for bioconcentration, followed by the length, with age being evaluated as a less significant factor.

  10. Identification of Plants That Inhibit Lipid Droplet Formation in Liver Cells: Rubus suavissimus Leaf Extract Protects Mice from High-Fat Diet-Induced Fatty Liver by Directly Affecting Liver Cells

    Science.gov (United States)

    Takahashi, Tomohiro; Sugawara, Wataru; Takiguchi, Yuya; Takizawa, Kento; Nakabayashi, Ami; Nakamura, Mitsuo; Nagano-Ito, Michiyo; Ichikawa, Shinichi

    2016-01-01

    Fatty liver disease is a condition in which abnormally large numbers of lipid droplets accumulate in liver cells. Fatty liver disease induces inflammation under conditions of oxidative stress and may result in cancer. To identify plants that protect against fatty liver disease, we examined the inhibitory effects of plant extracts on lipid droplet formation in mouse hepatoma cells. A screen of 98 water extracts of plants revealed 4 extracts with inhibitory effects. One of these extracts, Rubus suavissimus S. Lee (Tien-cha or Chinese sweet tea) leaf extract, which showed strong inhibitory effects, was tested in a mouse fatty liver model. In these mouse experiments, intake of the plant extract significantly protected mice against fatty liver disease without affecting body weight gain. Our results suggest that RSE directly affects liver cells and protects them from fatty liver disease. PMID:27429636

  11. LeafJ: an ImageJ plugin for semi-automated leaf shape measurement.

    Science.gov (United States)

    Maloof, Julin N; Nozue, Kazunari; Mumbach, Maxwell R; Palmer, Christine M

    2013-01-21

    High throughput phenotyping (phenomics) is a powerful tool for linking genes to their functions (see review and recent examples). Leaves are the primary photosynthetic organ, and their size and shape vary developmentally and environmentally within a plant. For these reasons studies on leaf morphology require measurement of multiple parameters from numerous leaves, which is best done by semi-automated phenomics tools. Canopy shade is an important environmental cue that affects plant architecture and life history; the suite of responses is collectively called the shade avoidance syndrome (SAS). Among SAS responses, shade induced leaf petiole elongation and changes in blade area are particularly useful as indices. To date, leaf shape programs (e.g. SHAPE, LAMINA, LeafAnalyzer, LEAFPROCESSOR) can measure leaf outlines and categorize leaf shapes, but can not output petiole length. Lack of large-scale measurement systems of leaf petioles has inhibited phenomics approaches to SAS research. In this paper, we describe a newly developed ImageJ plugin, called LeafJ, which can rapidly measure petiole length and leaf blade parameters of the model plant Arabidopsis thaliana. For the occasional leaf that required manual correction of the petiole/leaf blade boundary we used a touch-screen tablet. Further, leaf cell shape and leaf cell numbers are important determinants of leaf size. Separate from LeafJ we also present a protocol for using a touch-screen tablet for measuring cell shape, area, and size. Our leaf trait measurement system is not limited to shade-avoidance research and will accelerate leaf phenotyping of many mutants and screening plants by leaf phenotyping.

  12. Surface coating affects behavior of metallic nanoparticles in a biological environment

    Directory of Open Access Journals (Sweden)

    Darija Domazet Jurašin

    2016-02-01

    Full Text Available Silver (AgNPs and maghemite, i.e., superparamagnetic iron oxide nanoparticles (SPIONs are promising candidates for new medical applications, which implies the need for strict information regarding their physicochemical characteristics and behavior in a biological environment. The currently developed AgNPs and SPIONs encompass a myriad of sizes and surface coatings, which affect NPs properties and may improve their biocompatibility. This study is aimed to evaluate the effects of surface coating on colloidal stability and behavior of AgNPs and SPIONs in modelled biological environments using dynamic and electrophoretic light scattering techniques, as well as transmission electron microscopy to visualize the behavior of the NP. Three dispersion media were investigated: ultrapure water (UW, biological cell culture medium without addition of protein (BM, and BM supplemented with common serum protein (BMP. The obtained results showed that different coating agents on AgNPs and SPIONs produced different stabilities in the same biological media. The combination of negative charge and high adsorption strength of coating agents proved to be important for achieving good stability of metallic NPs in electrolyte-rich fluids. Most importantly, the presence of proteins provided colloidal stabilization to metallic NPs in biological fluids regardless of their chemical composition, surface structure and surface charge. In addition, an assessment of AgNP and SPION behavior in real biological fluids, rat whole blood (WhBl and blood plasma (BlPl, revealed that the composition of a biological medium is crucial for the colloidal stability and type of metallic NP transformation. Our results highlight the importance of physicochemical characterization and stability evaluation of metallic NPs in a variety of biological systems including as many NP properties as possible.

  13. Smart change in leaf morphology to tune the wettability

    Science.gov (United States)

    Kang, Hosung; Fleetwood, Sara; Jung, Sunghwan

    2016-11-01

    Plants are sessile organisms, but some of them are able to change their features to survive. We found Cercidiphyllum japonicum (Katsura) leaves actively adapt to their fine structures on the leaf surface in response to external stimuli. It is fascinating how the structural changes can affect their physical properties. In this present study, we are investigating the effect of external environments (temperature, cell hydration, and acid rain) on microscale papillose epidermal cells and nanoscale waxes. Using environmental scanning electron microscopy (ESEM) and atomic force microscopy (AFM), we measured micro and nano structures of the Katsura leaves. We found a functional relation between the micro and nano structures and the contact angle of the leaf's surface. As the epidermal cells shrink and the waxes erode, the contact angle decreases. A simple Cassie-Baxter model based on the wettability of textured surfaces has been used to characterize changes of the contact angle.

  14. Mendelian and non-mendelian mutations affecting surface antigen expression in Paramecium tetraurelia

    Energy Technology Data Exchange (ETDEWEB)

    Epstein, L.M.; Forney, J.D.

    1984-08-01

    A screening procedure was devised for the isolation of X-ray-induced mutations affecting the expression of the A immobilization antigen (i-antigen) in Paramecium tetraurelia. Two of the mutations isolated by this procedure proved to be in modifier genes. The two genes are unlinked to each other and unlinked to the structural A i-antigen gene. These are the first modifier genes identified in a Paramecium sp. that affect surface antigen expression. Another mutation was found to be a deletion of sequences just downstream from the A i-antigen gene. In cells carrying this mutation, the A i-antigen gene lies in close proximity to the end of a macronuclear chromosome. The expression of the A i-antigen is not affected in these cells, demonstrating that downstream sequences are not important for the regulation and expression of the A i-antigen gene. A stable cell line was also recovered which shows non-Mendelian inheritance of a macronuclear deletion of the A i-antigen gene. This mutant does not contain the gene in its macronucleus, but contains a complete copy of the gene in its micronucleus. In the cytoplasm of wild-type animals, the micronuclear gene is included in the developing macronucleus; in the cytoplasm of the mutant, the incorporation of the A i-antigen gene into the macronucleus is inhibited. This is the first evidence that a mechanism is available in ciliates to control the expression of a gene by regulating its incorporation into developing macronuclei.

  15. The threat of a support surface translation affects anticipatory postural control.

    Science.gov (United States)

    Phanthanourak, Angel L; Cleworth, Taylor W; Adkin, Allan L; Carpenter, Mark G; Tokuno, Craig D

    2016-10-01

    This study examined how postural threat in the form of a potential perturbation affects an individual's ability to perform a heel raise. Seventeen adults completed three conditions: i) low threat, where participants performed a heel raise in response to a "go" tone, ii) high threat, where participants either heard the same "go" tone, for which they performed a heel raise, or experienced a support surface translation in the medio-lateral direction that disturbed their balance, and iii) choice reaction time task, where participants either completed a heel raise in response to the same "go" tone or a toe raise in response to a lower pitched tone. For all heel raise trials, anticipatory postural adjustments (APAs) were quantified from center of pressure (COP) recordings and electromyographic (EMG) activity from the tibialis anterior (TA) and soleus (SOL). Results indicated that participants exhibited larger APAs, as reflected by the greater backward COP displacement (p=0.038) and velocity (p=0.022) as well as a larger TA EMG amplitude (p=0.045), during the high threat condition. During the execution phase of the heel raise, an earlier (p=0.014) and larger (p=0.041) SOL EMG activation were observed during the high threat condition. These results contrast with previous findings of reduced APAs when the postural threat was evoked through changes in surface height. Therefore, the characteristics of the postural threat must be considered to isolate the effects of threat on anticipatory movement control.

  16. Resource quality affects weapon and testis size and the ability of these traits to respond to selection in the leaf-footed cactus bug, Narnia femorata.

    Science.gov (United States)

    Sasson, Daniel A; Munoz, Patricio R; Gezan, Salvador A; Miller, Christine W

    2016-04-01

    The size of weapons and testes can be central to male reproductive success. Yet, the expression of these traits is often extremely variable. Studies are needed that take a more complete organism perspective, investigating the sources of variation in both traits simultaneously and using developmental conditions that mimic those in nature. In this study, we investigated the components of variation in weapon and testis sizes using the leaf-footed cactus bug, Narnia femorata (Hemiptera: Coreidae) on three natural developmental diets. We show that the developmental diet has profound effects on both weapon and testis expression and scaling. Intriguingly, males in the medium-quality diet express large weapons but have relatively tiny testes, suggesting complex allocation decisions. We also find that heritability, evolvability, and additive genetic variation are highest in the high-quality diet for testis and body mass. This result suggests that these traits may have an enhanced ability to respond to selection during a small window of time each year when this diet is available. Taken together, these results illustrate that normal, seasonal fluctuations in the nutritional environment may play a large role in the expression of sexually selected traits and the ability of these traits to respond to selection.

  17. Climate change conditions (elevated CO2 and temperature) and UV-B radiation affect grapevine (Vitis vinifera cv. Tempranillo) leaf carbon assimilation, altering fruit ripening rates.

    Science.gov (United States)

    Martínez-Lüscher, J; Morales, F; Sánchez-Díaz, M; Delrot, S; Aguirreolea, J; Gomès, E; Pascual, I

    2015-07-01

    The increase in grape berry ripening rates associated to climate change is a growing concern for wine makers as it rises the alcohol content of the wine. The present work studied the combined effects of elevated CO2, temperature and UV-B radiation on leaf physiology and berry ripening rates. Three doses of UV-B: 0, 5.98, 9.66 kJm(-2)d(-1), and two CO2-temperature regimes: ambient CO2-24/14 °C (day/night) (current situation) and 700 ppm CO2-28/18 °C (climate change) were imposed to grapevine fruit-bearing cuttings from fruit set to maturity under greenhouse-controlled conditions. Photosynthetic performance was always higher under climate change conditions. High levels of UV-B radiation down regulated carbon fixation rates. A transient recovery took place at veraison, through the accumulation of flavonols and the increase of antioxidant enzyme activities. Interacting effects between UV-B and CO2-temperature regimes were observed for the lipid peroxidation, which suggests that UV-B may contribute to palliate the signs of oxidative damage induced under elevated CO2-temperature. Photosynthetic and ripening rates were correlated. Thereby, the hastening effect of climate change conditions on ripening, associated to higher rates of carbon fixation, was attenuated by UV-B radiation.

  18. Improvement of oleuropein extractability by optimising steam blanching process as pre-treatment of olive leaf extraction via response surface methodology.

    Science.gov (United States)

    Stamatopoulos, Konstantinos; Katsoyannos, Evangelos; Chatzilazarou, Arhontoula; Konteles, Spyros J

    2012-07-15

    Impact of steam, hot water blanching and UV-C irradiation as pre-treatments on extraction of oleuropein and related biophenols from olive leaves (OLs), was investigated. Moreover, particle size effect of olive leaves and steam blanching duration were selected as independent variables to optimise steam blanching process in terms of oleuropein content (OC) and antioxidant activity (AC) of ethanolic extracts, by using response surface methodology. Optimum conditions for OC and AC were 10 min steam blanching of 20-11 and 3-1mm olive leaf fraction, respectively. Depending on the extraction procedure, at optimum conditions of steaming the results indicate that steam blanching of OL prior to extraction can significantly increase oleuropein yield from 25 to 35 times compared to non-steam blanched sample, whereas the antioxidant activity increased from 4 to 13 times. No significant UV-C effect was observed in OC and AC, while hot water blanched samples showed significantly higher oleuropein yields and antioxidant activity compared to untreated samples.

  19. STATISTICAL OPTIMIZATION OF AQUEOUS LEAF EXTRACT OF AERVA LANATA FOR CITRININ AND FUNGAL BIOMASS REDUCTION IN SUBMERGED FERMENTATION BY ASPERGILLUS NIGER USING RESPONSE SURFACE METHODOLOGY

    Directory of Open Access Journals (Sweden)

    Ajaz Ahmad

    2013-12-01

    Full Text Available Citrinin, a nephrotoxic mycotoxin produced by several fungal strains belonging to the genera Penicillium, Aspergillus, and Monascus. Generally found in stored grains and after their harvest. The objective of the present investigation was to study the antimicrobial activity (anti-fungal of aqueous leaf extract of Aerva lanata and to optimize its conditions for the maximum inhibition of citrinin and fungal biomass by Aspergillus niger. Optimization of culture conditions was carried out using Box-Behnken method of response surface methodology. Extent of inhibition of citrinin was carried out using HPLC and reduction in fungal biomass was carried out using dry cell weight after comparing with controls. Optimized culture conditions as per the point prediction tool were found to be 11.27 mg/L for concentration of Aerva lanata extract, nine and half days of incubation period and temperature of 25.5 °C resulted in maximum inhibition of citrinin. These optimized values of tested parameters were and compared with control citrinin production (243.28 mg/L and dry cell weight production (362.28mg.An average of 87.77±1.21% inhibition of citrinin and 80.02±1.42% of dry cell weight was obtained in an optimized medium at 9.5th d of fermentation with 97.82 % and 96.21% validity, respectively.

  20. Cedar leaf oil poisoning

    Science.gov (United States)

    Cedar leaf oil is made from some types of cedar trees. Cedar leaf oil poisoning occurs when someone swallows this substance. ... The substance in cedar leaf oil that can be harmful is thujone (a hydrocarbon).

  1. How Venus surface conditions evolution can be affected by large impacts at long timescales?

    Science.gov (United States)

    Gillmann, Cedric; Golabek, Gregor; Tackley, Paul

    2016-04-01

    Using numerical simulations, we investigate how the evolution of Venus' atmosphere and mantle is modified by large impacts, during Late Veneer and Late Heavy Bombardment. We propose a coupled model of mantle/atmosphere feedback. We also focus on volatile fluxes in and out of the atmosphere: atmospheric escape and degassing. The solid part of the planet is simulated using the StagYY code (Armann and Tackley, 2012) and releases volatiles into the atmosphere through degassing. Physical properties are depth-dependent. The assumed rheology is Newtonian diffusion creep plus plastic yielding. Atmospheric escape modeling involves two different aspects: hydrodynamic escape (0-500 Myr) and non-thermal escape mechanisms (dominant post 4 Ga). Hydrodynamic escape is the massive outflow of volatiles occurring when the solar energy input is strong. Post 4 Ga escape from non-thermal processes is comparatively low. The evolution of surface temperature is calculated from the greenhouse effect dependent on CO2 and water concentrations in the atmosphere, using a one-dimensional gray radiative-convective atmosphere model. It allows us to complete the coupling of the model: feedback of the atmosphere on the mantle is obtained by using surface temperature as a boundary condition for the convection. Large impacts are capable of contributing to (i) atmospheric escape, (ii) volatile replenishment and (iii) energy transfer to the mantle of the solid planet. We test a wide range of impactor parameters (size, velocity, timing) and different assumptions related to impact erosion (Shuvalov, 2010). For energy transfer, 2D distribution of the thermal anomaly created by the impact is used, leading to melting and subjected to transport by the mantle convection. Small (0-50 km) meteorites have a negligible effect on the global scale: they only affect the impact point and do not have lasting consequences on surface conditions. Medium ones (50-150 km) have strong short term influence through volatile

  2. Structural assessment of the impact of environmental constraints on Arabidopsis thaliana leaf growth: a 3D approach.

    Science.gov (United States)

    Wuyts, Nathalie; Massonnet, Catherine; Dauzat, Myriam; Granier, Christine

    2012-09-01

    Light and soil water content affect leaf surface area expansion through modifications in epidermal cell numbers and area, while effects on leaf thickness and mesophyll cell volumes are far less documented. Here, three-dimensional imaging was applied in a study of Arabidopsis thaliana leaf growth to determine leaf thickness and the cellular organization of mesophyll tissues under moderate soil water deficit and two cumulative light conditions. In contrast to surface area, thickness was highly conserved in response to water deficit under both low and high cumulative light regimes. Unlike epidermal and palisade mesophyll tissues, no reductions in cell number were observed in the spongy mesophyll; cells had rather changed in volume and shape. Furthermore, leaf features of a selection of genotypes affected in leaf functioning were analysed. The low-starch mutant pgm had very thick leaves because of unusually large palisade mesophyll cells, together with high levels of photosynthesis and stomatal conductance. By means of an open stomata mutant and a 9-cis-epoxycarotenoid dioxygenase overexpressor, it was shown that stomatal conductance does not necessarily have a major impact on leaf dimensions and cellular organization, pointing to additional mechanisms for the control of CO(2) diffusion under high and low stomatal conductance, respectively.

  3. Venation Skeleton-Based Modeling Plant Leaf Wilting

    Directory of Open Access Journals (Sweden)

    Shenglian Lu

    2009-01-01

    Full Text Available A venation skeleton-driven method for modeling and animating plant leaf wilting is presented. The proposed method includes five principal processes. Firstly, a three-dimensional leaf skeleton is constructed from a leaf image, and the leaf skeleton is further used to generate a detailed mesh for the leaf surface. Then a venation skeleton is generated interactively from the leaf skeleton. Each vein in the venation skeleton consists of a segmented vertices string. Thirdly, each vertex in the leaf mesh is banded to the nearest vertex in the venation skeleton. We then deform the venation skeleton by controlling the movement of each vertex in the venation skeleton by rotating it around a fixed vector. Finally, the leaf mesh is mapped to the deformed venation skeleton, as such the deformation of the mesh follows the deformation of the venation skeleton. The proposed techniques have been applied to simulate plant leaf surface deformation resulted from biological responses of plant wilting.

  4. Leaf Collection Posting Log

    Data.gov (United States)

    Montgomery County of Maryland — This dataset contains leaf collection dates for area and subarea where leaf collection service is provided by Montgomery County Department of Transportation. Update...

  5. Surface Structures Involved in Plant Stomata and Leaf Colonization by Shiga-Toxigenic Escherichia Coli O157:H7

    Science.gov (United States)

    Saldaña, Zeus; Sánchez, Ethel; Xicohtencatl-Cortes, Juan; Puente, Jose Luis; Girón, Jorge A.

    2011-01-01

    Shiga-toxigenic Escherichia coli (STEC) O157:H7 uses a myriad of surface adhesive appendages including pili, flagella, and the type 3 secretion system (T3SS) to adhere to and inflict damage to the human gut mucosa. Consumption of contaminated ground beef, milk, juices, water, or leafy greens has been associated with outbreaks of diarrheal disease in humans due to STEC. The aim of this study was to investigate which of the known STEC O157:H7 adherence factors mediate colonization of baby spinach leaves and where the bacteria reside within tainted leaves. We found that STEC O157:H7 colonizes baby spinach leaves through the coordinated production of curli, the E. coli common pilus, hemorrhagic coli type 4 pilus, flagella, and T3SS. Electron microscopy analysis of tainted leaves revealed STEC bacteria in the internal cavity of the stomata, in intercellular spaces, and within vascular tissue (xylem and phloem), where the bacteria were protected from the bactericidal effect of gentamicin, sodium hypochlorite or ozonated water treatments. We confirmed that the T3S escN mutant showed a reduced number of bacteria within the stomata suggesting that T3S is required for the successful colonization of leaves. In agreement, non-pathogenic E. coli K-12 strain DH5α transformed with a plasmid carrying the locus of enterocyte effacement (LEE) pathogenicity island, harboring the T3SS and effector genes, internalized into stomata more efficiently than without the LEE. This study highlights a role for pili, flagella, and T3SS in the interaction of STEC with spinach leaves. Colonization of plant stomata and internal tissues may constitute a strategy by which STEC survives in a nutrient-rich microenvironment protected from external foes and may be a potential source for human infection. PMID:21887151

  6. Euphorbia L. subsect. Esula (Boiss. in DC. Pax in the Iberian Peninsula. Leaf surface, chromosome numbers and taxonomic treatment

    Directory of Open Access Journals (Sweden)

    Molero, Julià

    1992-12-01

    Full Text Available We present a taxonomic study of the representatives or Euphorbia subsect. Esula in the Iberian Peninsula. Prior to this, a first section is included on the study of the leaf surface and a second section on chromosome numbers.
    The section on leaf surface is based on a study of the leaves or 45 populations of Iberian and European taxa of the subsections using a light microscope and SEM. The characters analyzed are cell shape, morphology of the cells and stomata (primary and secondary sculpture and epicuticular waxes (tertiary sculpture. Some microcharacters of the leaf surface proved particularly usefu1for taxonomical purposes. Thus the basic type of stoma and the distribution model of the stomata on the two sides of the leaf are characters which make it possible to separate taxa as closely related as E. esula L. subsp. esula and E. esula L. subsp orientalis (Boiss. in DC. Molero & Rovira. The morphological type of the epicuticular waxes also enables us to differentiate between E.graminifolia Vill. and E. esula aggr. And to distinguish subsp. bolosii Molero & Rovira from the remaining subespecies in E. nevadensis Boiss. & Reuter.
    Cytogenetic investigation reveals the presence of only the diploid cytotype (2n=10 in E. cyparissias L. and E. esula L. subsp. esula in the Iberian Peninsula. We describe for the first time in E. nevadensis s.1. a polyploidy complex with a base of x= 10 in which the diploid level (2n=20 is present in all subspecies; the tetraploid level (2n=40 is present in E. nevadensis subsp. nevadensis and the hexaploid level (2n=60 is found in E. nevadensis subsp. bolosii. Chromosome number is not a parameter that can be used for taxonomic purposes. In E. nevadensis, cytogenetic differentiation has followed its own course, with no apparent relationship to the process of morphological

  7. Do carotid MR surface coils affect PET quantification in PET/MR imaging?

    Energy Technology Data Exchange (ETDEWEB)

    Willemink, Martin J; Eldib, Mootaz [Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY (United States); Leiner, Tim [Department of Radiology, University Medical Center Utrecht, Utrecht (Netherlands); Fayad, Zahi A; Mani, Venkatesh [Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY (United States)

    2015-05-18

    To evaluate the effect of surface coils for carotid MR imaging on PET quantification in a clinical simultaneous whole-body PET/MR scanner. A cylindrical phantom was filled with a homogeneous 2L water-FDG mixture at a starting dose of 301.2MBq. Clinical PET/MR and PET/CT systems were used to acquire PET-data without a coil (reference standard) and with two carotid MRI coils (Siemens Special Purpose 8-Channel and Machnet 4-Channel Phased Array). PET-signal attenuation was evaluated with Osirix using 51 (PET/MR) and 37 (PET/CT) circular ROIs. Mean and maximum standardized uptake values (SUVs) were quantified for each ROI. Furthermore, SUVs of PET/MR and PET/CT were compared. For validation, a patient was scanned with an injected dose of 407.7MBq on both a PET/CT and a PET/MR system without a coil and with both coils. PET/MR underestimations were -2.2% (Siemens) and -7.8% (Machnet) for SUVmean, and -1.2% (Siemens) and -3.3% (Machnet) for SUVmax, respectively. For PET/CT, underestimations were -1.3% (Siemens) and -1.4% (Machnet) for SUVmean and -0.5% (both Siemens and Machnet) for SUVmax, respectively using no coil data as reference. Except for PET/CT SUVmax values all differences were significant. SUVs differed significantly between PET/MR and PET/CT with SUVmean values of 0.51-0.55 for PET/MR and 0.68-0.69 for PET/CT, respectively. The patient examination showed that median SUVmean values measured in the carotid arteries decreased from 0.97 without a coil to 0.96 (Siemens) and 0.88 (Machnet). Carotid surface coils do affect attenuation correction in both PET/MR and PET/CT imaging. Furthermore, SUVs differed significantly between PET/MR and PET/CT.

  8. Integrating ASCAT surface soil moisture and GEOV1 leaf area index into the SURFEX modelling platform: a land data assimilation application over France

    Directory of Open Access Journals (Sweden)

    A. L. Barbu

    2014-01-01

    Full Text Available The land monitoring service of the European Copernicus programme has developed a set of satellite-based biogeophysical products, including surface soil moisture (SSM and leaf area index (LAI. This study investigates the impact of joint assimilation of remotely sensed SSM derived from Advanced Scatterometer (ASCAT backscatter data and the Copernicus Global Land GEOV1 satellite-based LAI product into the the vegetation growth version of the Interactions between Soil Biosphere Atmosphere (ISBA-A-gs land surface model within the the externalised surface model (SURFEX modelling platform of Météo-France. The ASCAT data were bias corrected with respect to the model climatology by using a seasonal-based CDF (Cumulative Distribution Function matching technique. A multivariate multi-scale land data assimilation system (LDAS based on the extended Kalman Filter (EKF is used for monitoring the soil moisture, terrestrial vegetation, surface carbon and energy fluxes across the domain of France at a spatial resolution of 8 km. Each model grid box is divided into a number of land covers, each having its own set of prognostic variables. The filter algorithm is designed to provide a distinct analysis for each land cover while using one observation per grid box. The updated values are aggregated by computing a weighted average. In this study, it is demonstrated that the assimilation scheme works effectively within the ISBA-A-gs model over a four-year period (2008–2011. The EKF is able to extract useful information from the data signal at the grid scale and distribute the root-zone soil moisture and LAI increments throughout the mosaic structure of the model. The impact of the assimilation on the vegetation phenology and on the water and carbon fluxes varies from one season to another. The spring drought of 2011 is an interesting case study of the potential of the assimilation to improve drought monitoring. A comparison between simulated and in situ soil

  9. Application of target partial least squares for analysis of Fourier transform infrared-attenuated total reflection hyperspectral images for characterization of the distribution of crop protection products on the leaf surface.

    Science.gov (United States)

    Budevska, Boiana O

    2009-09-01

    Target partial least squares (PLS) is applied to Fourier transform infrared-attenuated total reflection (FT-IR-ATR) hyperspectral images of plant leaf surface treated with crop protection products. Detection of active ingredient is demonstrated at application rates of 50 g active ingredient per hectare. This sensitivity could not be achieved without the application of multivariate analysis. Quantitative information appears to be easily recovered through analysis of combined images with known and unknown amounts of active ingredient.

  10. Leaf Length Variation in Perennial Forage Grasses

    Directory of Open Access Journals (Sweden)

    Philippe Barre

    2015-08-01

    Full Text Available Leaf length is a key factor in the economic value of different grass species and cultivars in forage production. It is also important for the survival of individual plants within a sward. The objective of this paper is to discuss the basis of within-species variation in leaf length. Selection for leaf length has been highly efficient, with moderate to high narrow sense heritability. Nevertheless, the genetic regulation of leaf length is complex because it involves many genes with small individual effects. This could explain the low stability of QTL found in different studies. Leaf length has a strong response to environmental conditions. However, when significant genotype × environment interactions have been identified, their effects have been smaller than the main effects. Recent modelling-based research suggests that many of the reported environmental effects on leaf length and genotype × environment interactions could be biased. Indeed, it has been shown that leaf length is an emergent property strongly affected by the architectural state of the plant during significant periods prior to leaf emergence. This approach could lead to improved understanding of the factors affecting leaf length, as well as better estimates of the main genetic effects.

  11. 5个榕树品种叶表面微形态结构与滞尘能力比较%Leaf surface microstructures of five Ficus species and comparison of their dust detaining capabilities

    Institute of Scientific and Technical Information of China (English)

    陈雪华

    2011-01-01

    [目的]测定不同榕树品种的滞尘能力,为正确选用榕树作为城市绿化树种提供科学依据.[方法]以细叶榕(Ficus microcarpa)、柳叶榕(Ficus heteropleura)、对叶榕(Ficus hispida)、高山榕(Ficus altissima)、黄褐榕(Ficus virens)等5个榕树品种的成熟叶片为试验材料,应用扫描电子显微镜和滤纸恒重法观察叶片表面微形态结构,测定叶片滞尘量,并进行5个榕树品种滞尘能力比较.[结果]5个榕树品种的叶表面在表皮细胞、表皮纤毛、气孔等微形态结构上存在明显差异,对叶榕叶表面结构粗糙,具有蜂窝状的凹坑组织和表皮纤毛;细叶榕有不规则的岛状表皮细胞突起和大小不等的坑状组织,没有表皮纤毛;黄褐榕叶表面支脉细胞突起形成一个个的网格结构,无表皮纤毛;柳叶榕和高山榕叶表面较光滑,均无表皮纤毛.5个榕树品种因叶表面结构不同,滞尘能力也表现出明显差异.[结论]榕树叶片的形态特征是决定榕树叶片滞尘量的关键,5种榕树品种滞尘能力大小依次为:对叶榕>细叶榕>黄褐榕>高山榕>柳叶榕.%[Objective]The present study was conducted to determine the dust detaining capabilities of different Ficus species in order to screen some suitable urban greening Ficus species.[Method]Mature leaves of five Ficus species, viz., Ficus microcarpa, Ficus heteropleura, Ficus hispida, Ficus altissitna and Ficus virens were collected from Haikou City (Hainan, China). Scanning electronic microscope and filter paper constant weight methods were used to observe the leaf surface micro-morphological structures of the five Ficus species, and their dust detaining capabilities were compared.[Result ]The microscopic photos showed significantly different leaf surface micro-morphological structures of the five Ficus species. The leaf surface structure of Ficus hispida was coarse, with honeycomb-like pit tissues and concentrated threadlike cilia. Ficus

  12. Analyses of Impact of Needle Surface Properties on Estimation of Needle Absorption Spectrum: Case Study with Coniferous Needle and Shoot Samples

    Directory of Open Access Journals (Sweden)

    Bin Yang

    2016-07-01

    Full Text Available Leaf scattering spectrum is the key optical variable that conveys information about leaf absorbing constituents from remote sensing. It cannot be directly measured from space because the radiation scattered from leaves is affected by the 3D canopy structure. In addition, some radiation is specularly reflected at the surface of leaves. This portion of reflected radiation is partly polarized, does not interact with pigments inside the leaf and therefore contains no information about its interior. Very little empirical data are available on the spectral and angular scattering properties of leaf surfaces. Whereas canopy-structure effects are well understood, the impact of the leaf surface reflectance on estimation of leaf absorption spectra remains uncertain. This paper presents empirical and theoretical analyses of angular, spectral, and polarimetric measurements of light reflected by needles and shoots of Pinus koraiensis and Picea koraiensis species. Our results suggest that ignoring the leaf surface reflected radiation can result in an inaccurate estimation of the leaf absorption spectrum. Polarization measurements may be useful to account for leaf surface effects because radiation reflected from the leaf surface is partly polarized, whereas that from the leaf interior is not.

  13. Marine organic geochemistry in industrially affected coastal areas in Greece: Hydrocarbons in surface sediments

    Science.gov (United States)

    Hatzianestis, Ioannis

    2015-04-01

    Hydrocarbons are abundant components of the organic material in coastal zones. Their sources are mainly anthropogenic, but several natural ones have also been recognized. Among hydrocarbons, the polycyclic aromatic ones (PAHs) have received special attention since they considered as hazardous environmental chemicals and are included in priority pollutant lists. The purpose of this study was to investigate the distribution, sources and transport pathways of hydrocarbons in marine areas in Greece directly influenced from the operation of major industrial units in the coastal zone by using a molecular marker approach, characteristic compositional patterns and related indices and also to evaluate their potential toxicity. Thirty two surface sediment samples were collected from three marine areas: a) Antikyra bay in Korinthiakos gulf, affected from the operation of an alumina and production plant b) Larymna bay in Noth Evoikos, affected from the operation of a nickel production plant and c) Aliveri bay in South Evoikos Gulf, affected from a cement production plant. In all the studied areas aquaculture and fishing activities have been also developed in the coastal zone. High aliphatic hydrocarbon (AHC) concentrations (~500 μg/g), indicating significant petroleum related inputs, were measured only in Antikyra bay. In all the other samples, AHC values were below 100 μg/g. N-alkanes were the most prominent resolved components (R) with an elevated odd to even carbon number preference, revealing the high importance of terrestrial inputs in the study areas. The unresolved complex mixture (UCM) was the major component of the aliphatic fraction (UCM/R > 4), indicating a chronic oil pollution. A series of hopanes were also identified, with patterns characteristic of oil-derived hydrocarbons, further confirming the presence of pollutant inputs from fossil fuel products. Extremely high PAH concentrations (> 100,000 ng/g) were found in the close vicinity of the alumina production

  14. 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

  15. Adult nutrition, but not inbreeding, affects male primary sexual traits in the leaf-footed cactus bug Narnia femorata (Hemiptera: Coreidae).

    Science.gov (United States)

    Joseph, Paul N; Sasson, Daniel A; Allen, Pablo E; Somjee, Ummat; Miller, Christine W

    2016-07-01

    Adverse conditions may be the norm rather than the exception in natural populations. Many populations experience poor nutrition on a seasonal basis. Further, brief interludes of inbreeding can be common as population density fluctuates and because of habitat fragmentation. Here, we investigated the effects of poor nutrition and inbreeding on traits that can be very important to reproductive success and fitness in males: testes mass, sperm concentration, and sperm viability. Our study species was Narnia femorata, a species introduced to north-central Florida in the 1950s. This species encounters regular, seasonal changes in diet that can have profound phenotypic effects on morphology and behavior. We generated inbred and outbred individuals through a single generation of full-sibling mating or outcrossing, respectively. All juveniles were provided a natural, high-quality diet of Opuntia humifusa cactus cladode with fruit until they reached adulthood. New adult males were put on a high- or low-quality diet for at least 21 days before measurements were taken. As expected, the low-quality diet led to significantly decreased testes mass in both inbred and outbred males, although there were surprisingly no detectable effects on sperm traits. We did not find evidence that inbreeding affected testes mass, sperm concentration, and sperm viability. Our results highlight the immediate and overwhelming effects of nutrition on testes mass, while suggesting that a single generation of inbreeding might not be detrimental for primary sexual traits in this particular population.

  16. Why so strong for the lotus leaf?

    Science.gov (United States)

    Guo, Zhiguang; Liu, Weimin; Su, Bao-Lian

    2008-11-01

    The authors discussed the potential reasons why the lotus leaf is so strong by means of scanning electron microscopy (SEM). The results showed that the good mechanical properties of lotus leaf should be attributed to its architecture, such as paralleled microtubes structure, umbrellalike structure, and hierarchically layered hexagon structure. The important observation from this work is that the surface of the rear face of the lotus leaf seems to be constituted by the layers of hexagons whose hierarchical pilling up of size decreases as we go deeper from surface. This is a typical fractal-like phenomenon.

  17. Absence of OsβCA1 causes CO2 deficit and affects leaf photosynthesis and stomatal response to CO2 in rice.

    Science.gov (United States)

    Chen, Taiyu; Wu, Huan; Wu, Jiemin; Fan, Xiaolei; Li, Xianghua; Lin, Yongjun

    2017-01-31

    Plants always adjust the opening of stomatal pores to adapt to the environments, such as [CO2 ], humidity and temperature. Low [CO2 ] will trigger the opening of stomatal pores to absorb extra CO2 . However, little is known about how CO2 supply affects the carbon fixation and opening of stomatal pores in rice. Here, a chloroplast-located β-carbonic anhydrase (β-CA) coding gene was found to be involved in carbon assimilation and CO2 -mediated stomatal pore response in rice. OsβCA1 was constitutively expressed in all tissues and its transcripts were induced by high [CO2 ] in leaves. Both T-DNA mutant and RNAi lines showed phenotypes of lower biomass and CA activities. The knock-out of OsβCA1 obviously decreased the photosynthesis capacity, as demonstrated by the increased CO2 compensation point and decreased light saturation point in the mutant; while the knock-out increased the opening ratio of stomatal pores and water loss rate. Moreover, the mutant showed a delayed response to low [CO2 ], and they could not be closed to the degree of wild plants even though the stomatal pores could rapidly respond to high [CO2 ]. Genome-wide gene expression analysis via RNA-seq demonstrated that the transcript abundance of the genes related to RuBisCO, photosystem compounds and opening of stomatal pores were globally up-regulated in the mutant. Taken together, the inadequate CO2 supply caused by the absence of OsβCA1 reduces photosynthesis efficiency, triggers the opening of stomatal pores and finally decreases their sensitivity to CO2 fluctuation. This article is protected by copyright. All rights reserved.

  18. Nanoscale roughness and morphology affect the IsoElectric Point of titania surfaces.

    Directory of Open Access Journals (Sweden)

    Francesca Borghi

    Full Text Available We report on the systematic investigation of the role of surface nanoscale roughness and morphology on the charging behaviour of nanostructured titania (TiO2 surfaces in aqueous solutions. IsoElectric Points (IEPs of surfaces have been characterized by direct measurement of the electrostatic double layer interactions between titania surfaces and the micrometer-sized spherical silica probe of an atomic force microscope in NaCl aqueous electrolyte. The use of a colloidal probe provides well-defined interaction geometry and allows effectively probing the overall effect of nanoscale morphology. By using supersonic cluster beam deposition to fabricate nanostructured titania films, we achieved a quantitative control over the surface morphological parameters. We performed a systematical exploration of the electrical double layer properties in different interaction regimes characterized by different ratios of characteristic nanometric lengths of the system: the surface rms roughness Rq, the correlation length ξ and the Debye length λD. We observed a remarkable reduction by several pH units of IEP on rough nanostructured surfaces, with respect to flat crystalline rutile TiO2. In order to explain the observed behavior of IEP, we consider the roughness-induced self-overlap of the electrical double layers as a potential source of deviation from the trend expected for flat surfaces.

  19. Nanoscale roughness and morphology affect the IsoElectric Point of titania surfaces.

    Science.gov (United States)

    Borghi, Francesca; Vyas, Varun; Podestà, Alessandro; Milani, Paolo

    2013-01-01

    We report on the systematic investigation of the role of surface nanoscale roughness and morphology on the charging behaviour of nanostructured titania (TiO2) surfaces in aqueous solutions. IsoElectric Points (IEPs) of surfaces have been characterized by direct measurement of the electrostatic double layer interactions between titania surfaces and the micrometer-sized spherical silica probe of an atomic force microscope in NaCl aqueous electrolyte. The use of a colloidal probe provides well-defined interaction geometry and allows effectively probing the overall effect of nanoscale morphology. By using supersonic cluster beam deposition to fabricate nanostructured titania films, we achieved a quantitative control over the surface morphological parameters. We performed a systematical exploration of the electrical double layer properties in different interaction regimes characterized by different ratios of characteristic nanometric lengths of the system: the surface rms roughness Rq, the correlation length ξ and the Debye length λD. We observed a remarkable reduction by several pH units of IEP on rough nanostructured surfaces, with respect to flat crystalline rutile TiO2. In order to explain the observed behavior of IEP, we consider the roughness-induced self-overlap of the electrical double layers as a potential source of deviation from the trend expected for flat surfaces.

  20. The interaction between the tennis court and the player: how does surface affect leg stiffness?

    Science.gov (United States)

    Maquirriain, Javier

    2013-03-01

    An adequate level of leg stiffness is necessary for an optimal tennis performance and leg stiffness should be adapted to frequently changing surfaces as tennis players usually play on different courts. The aim of this study was to evaluate leg stiffness in competitive tennis players on different court surfaces. Ten healthy competitive tennis players (nine men and one woman; mean age = 17.6 +/- 3.2 years) underwent leg stiffness testing by modeling the vertical ground reaction force using an optical system. Flight time and contact time were determined during hopping on two different tennis court surfaces (clay and acrylic). No significant difference was found in the flight time, contact time, and jump height between the surfaces. No significant difference in leg stiffness was found between the surfaces (18.25 +/- 5.8 and 19.27 +/- 4.9 kN/m for clay and acrylic, respectively; p = 0.28). This study demonstrated that contact time and flight time as well as leg stiffness of tennis players remained unchanged when hopping on two different tennis surfaces. Results of this research provide objective data regarding the tennis-specific loading of the locomotor system and proper mechanical adaptation of the player on different surfaces, which may be useful for testing protocols and planning training programs.

  1. Climatological Factors Affecting Electromagnetic Surface Ducting in the Aegean Sea Region

    Science.gov (United States)

    2012-03-01

    19  x Figure 11.  The Azores or Bermuda High and southwest and south-central Asia thermal low tend to produce a...of Frequency (green lines with triangle markers), moisture mixing ratio at the surface level (blue lines with rhombus markers) and moisture mixing...of Frequency (green lines with triangle markers), moisture mixing ratio at the surface level (blue lines with rhombus markers) and moisture mixing

  2. Impact of epidermal leaf mining by the aspen leaf miner (Phyllocnistis populiella) on the growth, physiology, and leaf longevity of quaking aspen.

    Science.gov (United States)

    Wagner, Diane; DeFoliart, Linda; Doak, Patricia; Schneiderheinze, Jenny

    2008-08-01

    The aspen leaf miner, Phyllocnistis populiella, feeds on the contents of epidermal cells on both top (adaxial) and bottom (abaxial) surfaces of quaking aspen leaves, leaving the photosynthetic tissue of the mesophyll intact. This type of feeding is taxonomically restricted to a small subset of leaf mining insects but can cause widespread plant damage during outbreaks. We studied the effect of epidermal mining on aspen growth and physiology during an outbreak of P. populiella in the boreal forest of interior Alaska. Experimental reduction of leaf miner density across two sites and 3 years significantly increased annual aspen growth rates relative to naturally mined controls. Leaf mining damage was negatively related to leaf longevity. Leaves with heavy mining damage abscised 4 weeks earlier, on average, than leaves with minimal mining damage. Mining damage to the top and bottom surfaces of leaves had different effects on physiology. Mining on the top surface of the leaf had no significant effect on photosynthesis or conductance and was unrelated to leaf stable C isotope ratio (delta(13)C). Mining damage to the bottom leaf surface, where stomata are located, had significant negative effects on net photosynthesis and water vapor conductance. Percent bottom mining was positively related to leaf delta(13)C. Taken together, the data suggest that the primary mechanism for the reduction of photosynthesis by epidermal leaf mining by P. populiella is the failure of stomata to open normally on bottom-mined leaves.

  3. Study on water loss of the surface stream affected by longwall mining

    Institute of Scientific and Technical Information of China (English)

    GUO Wen-bing; Syd S.Peng

    2007-01-01

    In order to study the effect of longwalI mining on suface stream water,monitoring stations of water flow rate was established.A lot of water flowing data were collected before,during and after longwall mining.Based on monitoring data,the effects of longwall mining on surface stream water were analyzed.The results demonstrate that longwall mining has effects on the surface stream water:and the stream water would be lost and decrease due to longwall mining but never go into underground through fractured zone.Also.the mechanism of water loss due to longwall mining was presented.The stream water can go into the surface cracks in the intersection of stream and surface cracks.longwall mining subsidence can change the surface stream slope and the downstream water flowing status.The results also show the effects of longwall mining on stream water are temporary and about one or two years later,surface stream water can be recovered.

  4. Factors affecting the spontaneous motion of condensate drops on superhydrophobic copper surfaces.

    Science.gov (United States)

    Feng, Jie; Qin, Zhaoqian; Yao, Shuhuai

    2012-04-10

    The coalescence-induced condensate drop motion on some superhydrophobic surfaces (SHSs) has attracted increasing attention because of its potential applications in sustained dropwise condensation, water collection, anti-icing, and anticorrosion. However, an investigation of the mechanism of such self-propelled motion including the factors for designing such SHSs is still limited. In this article, we fabricated a series of superhydrophobic copper surfaces with nanoribbon structures using wet chemical oxidation followed by fluorization treatment. We then systematically studied the influence of surface roughness and the chemical properties of as-prepared surfaces on the spontaneous motion of condensate drops. We quantified the "frequency" of the condensate drop motion based on microscopic sequential images and showed that the trend of this frequency varied with the nanoribbon structure and extent of fluorination. More obvious spontaneous condensate drop motion was observed on surfaces with a higher extent of fluorization and nanostructures possessing sufficiently narrow spacing and higher perpendicularity. We attribute this enhanced drop mobility to the stable Cassie state of condensate drops in the dynamic dropwise condensation process that is determined by the nanoscale morphology and local surface energy.

  5. Colloidal mobilization of arsenic from mining-affected soils by surface runoff.

    Science.gov (United States)

    Gomez-Gonzalez, Miguel Angel; Voegelin, Andreas; Garcia-Guinea, Javier; Bolea, Eduardo; Laborda, Francisco; Garrido, Fernando

    2016-02-01

    Scorodite-rich wastes left as a legacy of mining and smelting operations pose a threat to environmental health. Colloids formed by the weathering of processing wastes may control the release of arsenic (As) into surface waters. At a former mine site in Madrid (Spain), we investigated the mobilization of colloidal As by surface runoff from weathered processing wastes and from sediments in the bed of a draining creek and a downstream sedimentation-pond. Colloids mobilized by surface runoff during simulated rain events were characterized for their composition, structure and mode of As uptake using asymmetric flow field-flow fractionation coupled to inductively plasma mass spectrometry (AF4-ICP-MS) and X-ray absorption spectroscopy (XAS) at the As and Fe K-edges. Colloidal scorodite mobilized in surface runoff from the waste pile is acting as a mobile As carrier. In surface runoff from the river bed and the sedimentation pond, ferrihydrite was identified as the dominant As-bearing colloidal phase. The results from this study suggest that mobilization of As-bearing colloids by surface runoff may play an important role in the dispersion of As from metallurgical wastes deposited above ground and needs to be considered in risk assessment.

  6. Comparison of surface ultrastructure of stem and leaf in 4 varieties of Vitis vinifera%4个葡萄品种茎叶表面微结构的比较

    Institute of Scientific and Technical Information of China (English)

    邵邻相; 李美; 徐玲玲

    2012-01-01

    It was studied the differences of stem and leaf surface ultrastructure of 4 varieties of Vitis vinifera: Superfujiminori, Fujiminori, Izunishiki, Pioneer. Fresh stems and leaves of 4 varieties of Vitis vinifera were observed by scanning electronic microscope (SEM). There were differences on the surface ultrastructure of leaf, stem, tendril, the main vein and each grape had some special ultrastructures. There were sunk stoma on main vein of Pioneer; the epidermic cells of Fujiminori had inerratic dents j the bristles of Izunishiki were thick and strong; the cord-like ornamentation of Superfujiminori were wavy-looking. Compared with Fujiminori, the surface ultrastructure of leaf, stem, tendril of Superfujiminori were different. Surface ultrastructure of stem and leaf would offer more morphological evidences for distinguishing different varieties of Vitis vinifera.%用扫描电镜观察比较了超藤、藤稔、伊豆锦和先锋4个品种葡萄的新鲜茎叶表面细微结构的差异.4个品种葡萄的叶、茎、卷须和叶主脉的表面细微结构不同,各自具有独特的细微构造:先锋叶上表面主脉具有凹陷型的气孔;藤稔茎表皮细胞表面具有规则的凹陷;伊豆锦刚毛粗壮;超藤卷须表面的索条状纹饰呈波状.新品种超藤的叶、茎和卷须表面的微结构与其母本藤稔有着较显著的区别.4个品种葡萄茎叶表面细微结构存在的明显差异,为葡萄品种鉴别提供了更多的形态学依据.

  7. Lightning attachment to wind turbine surfaces affected by internal blade conditions

    DEFF Research Database (Denmark)

    Garolera, Anna Candela; Holboell, Joachim; Madsen, Soren Find

    2012-01-01

    on the blade surface instead of the receptor is also possible, with the risk of damages in the composite structure as a consequence. The present paper focuses on electrical fields and streamer activity in connection to conductive components inside a wind turbine blade when a downward leader is approaching...

  8. Detoxification of Implant Surfaces Affected by Peri-Implant Disease: An Overview of Surgical Methods

    Directory of Open Access Journals (Sweden)

    Pilar Valderrama

    2013-01-01

    Full Text Available Purpose. Peri-implantitis is one of the major causes of implant failure. The detoxification of the implant surface is necessary to obtain reosseointegration. The aim of this review was to summarize in vitro and in vivo studies as well as clinical trials that have evaluated surgical approaches for detoxification of the implant body surfaces. Materials and Methods. A literature search was conducted using MEDLINE (PubMed from 1966 to 2013. The outcome variables were the ability of the therapeutic method to eliminate the biofilm and endotoxins from the implant surface, the changes in clinical parameters, radiographic bone fill, and histological reosseointegration. Results. From 574 articles found, 76 were analyzed. The findings, advantages, and disadvantages of using mechanical, chemical methods and lasers are discussed. Conclusions. Complete elimination of the biofilms is difficult to achieve. All therapies induce changes of the chemical and physical properties of the implant surface. Partial reosseointegration after detoxification has been reported in animals. Combination protocols for surgical treatment of peri-implantitis in humans have shown some positive clinical and radiographic results, but long-term evaluation to evaluate the validity and reliability of the techniques is needed.

  9. Iodine Disinfection of Sea Trout, Salmo Trutta (L., Eggs and the Affect on Egg Surfaces

    Directory of Open Access Journals (Sweden)

    Zawada Adam

    2014-07-01

    Full Text Available The aim of the research was to investigate the impact iodine solution disinfection had on Salmo trutta (L. egg survival rates during incubation, and to determine the effect of the disinfection procedure on egg shells using scanning microscopy. The study groups were bathed in a Desamar K30 solution at a concentration of 100 ml per 10 dm-3 for 10 m once after the eggs had hardened and four times after the eyed stage. Egg samples for scanning analyses were collected on day 30 of incubation at the eyed stage after the first bath in the iodophor solution, and then at the end of incubation. Egg surface images were analyzed for the number of bacteria, the presence of hyphae, and the egg surface area covered with sediments. No statistically significant differences were noted in embryo survival rates in the groups that were disinfected. The highest number of bacteria was observed on egg surfaces which had not been disinfected prior to hatching. A significant amount of sediment was observed on the eggs during incubation. On day 90 of incubation, all of the egg surfaces were covered with sediments. Disinfection was not noted to have had a significant impact on the presence of hyphae. Iodophor preparations can be used for routine disinfection of trout eggs; however, other means of disinfection should be applied before the eyed egg stage.

  10. Influence of tillage on adult and immature pea leaf weevil (Coleoptera: Curculionidae) densities in pea.

    Science.gov (United States)

    Hanavan, Ryan P; Bosque-Pérez, Nilsa A; Schotzko, Dennis J; Eigenbrode, Sanford D

    2010-06-01

    The pea leaf weevil, Sitona lineatus (L.) (Coleoptera: Curculionidae), has been a major pest of pea, Pisum sativum L., in eastern Washington and northern Idaho since its introduction to the region in the early 1970s. Eggs are deposited in the spring on the soil surface and first instars hatch and move to pea root nodules, where larvae feed before they pupate and adults emerge in mid- to late summer. No-tillage practices are known to reduce pea leaf weevil colonization in pea, but the effects of tillage on larval densities and subsequent adult emergence have not been examined. During 2005, 2006, and 2007, we compared densities of colonizing adult and immature pea leaf weevils on pea plots grown using conventional tillage and no-tillage. In 2005 and 2006, emergence of adult pea leaf weevil was monitored in the same plots. Densities of colonizing adult and immature pea leaf weevil were significantly higher in conventional tillage plots. Larvae in conventional tillage were further along in development than larvae in no-tillage plots during June and July. Densities of emerging adult pea leaf weevil were significantly greater from conventional tillage than no-tillage plots. Based on densities of colonizing and subsequent emerging adults, survival of weevils from egg through adult was greater in conventional tillage plots. Soils under no-tillage are cooler, resulting in later emergence of the pea crop and delayed root nodule development, possibly affecting the ability of first-instar pea leaf weevil to locate host plant roots. Our results indicate no-tillage fields are less suitable for pea leaf weevil colonization and survival than conventional tillage fields.

  11. Surface conductivity of Mercury provides current closure and may affect magnetospheric symmetry

    Directory of Open Access Journals (Sweden)

    P. Janhunen

    2004-04-01

    Full Text Available We study what effect a possible surface conductivity of Mercury has on the closure of magnetospheric currents by making six runs with a quasi-neutral hybrid simulation. The runs are otherwise identical but use different synthetic conductivity models: run 1 has a fully conducting planet, run 2 has a poorly conducting planet ( $sigma{=}10^{-8} Omega^{-1}$ m$^{-1}$ and runs 3-6 have one of the hemispheres either in the dawn-dusk or day-night directions, conducting well, the other one being conducting poorly. Although the surface conductivity is not known from observations, educated guesses easily give such conductivity values that magnetospheric currents may close partly within the planet, and as the conductivity depends heavily on the mineral composition of the surface, the possibility of significant horizontal variations cannot be easily excluded. The simulation results show that strong horizontal variations may produce modest magnetospheric asymmetries. Beyond the hybrid simulation, we also briefly discuss the possibility that in the nightside there may be a lack of surface electrons to carry downward current, which may act as a further source of surface-related magnetospheric asymmetry.

    Key words. Magnetospheric physics (planetary magnetospheres; current systems; solar wind-magnetosphere interactions.6

  12. [Leaf anatomy of the mosaic ficus benjamina cv. Starlight and interaction of source and sink chimera components].

    Science.gov (United States)

    Labunskaia, E A; Zhigalova, T V; Chub, V V

    2007-01-01

    Leaf anatomy was studied in the mosaic Ficus benjamina cv. Starlight and non-chimeric Ficus benjamina cv. Daniel. The number of chloroplasts in a white, chlorophyll-deficient tissue declines as compared to the green tissue. However, their functional activity is retained. The leaf of the mosaic F. benjamina contains two or, sometimes, three subepidermal layers. Mesophyll forms one layer in the green and white parts of leaf palisade and one white and one green layer in the transitional zone (edge). In the transitional zone, green spongy mesophyll is located between two white spongy layers and the proportion of photosynthesizing cells varies. In cv. Daniel, there are two subepidermal layers and one layer of columnar mesophyll cells. According to the morphometry data, the proportion of white zone in the leaf correlates with the leaf position in the whole shoot: the higher the branch order, the larger the proportion of white zone. The total leaf area depends also on its position in the shoot. No such correlation was found in non-chimeric F. benjamina cv. Daniel. In the mosaic chimera, the source-sink status appears to depend on the leaf position in the shoot. Experiments with individual shoots of the same order and elimination of all lateral shoots have shown that the proportion of white zone in new leaves on the shoot increases with the total area of green zone. Thus, the area of assimilating shoot surface affects the formation of leaves in the meristem. A hypothesis was put forward that the source-sink state affects the ratio of green and white parts in the leaf primordium. Products of photosynthesis (carbohydrates) are a possible metabolic signal affecting the meristem. It cannot be excluded as well that the hormonal state undergoes changes in the chimeric plant.

  13. Precursor type affecting surface properties and catalytic activity of sulfated zirconia

    Directory of Open Access Journals (Sweden)

    Zarubica Aleksandra R.

    2007-01-01

    Full Text Available Zirconium-hydroxide precursor samples are synthesized from Zr-hydroxide, Zr-nitrate, and Zr-alkoxide, by precipitation/impregnation, as well as by a modified sol-gel method. Precursor samples are further sulphated for the intended SO4 2- content of 4 wt.%, and calcined at 500-700oC. Differences in precursors’ origin and calcination temperature induce the incorporation of SO4 2- groups into ZrO2 matrices by various mechanisms. As a result, different amounts of residual sulphates are coupled with other structural, as well as surface properties, resulting in various catalytic activities of sulphated zirconia samples. Catalyst activity and selectivity are a complex synergistic function of tetragonal phase fraction, sulphates contents, textural and surface characteristics. Superior activity of SZ of alkoxide origin can be explained by a beneficial effect of meso-pores owing to a better accommodation of coke deposits.

  14. Type of Ground Surface during Plyometric Training Affects the Severity of Exercise-Induced Muscle Damage

    Directory of Open Access Journals (Sweden)

    Hamid Arazi

    2016-03-01

    Full Text Available The purpose of this study was to compare the changes in the symptoms of exercise-induced muscle damage from a bout of plyometric exercise (PE; 10 × 10 vertical jumps performed in aquatic, sand and firm conditions. Twenty-four healthy college-aged men were randomly assigned to one of three groups: Aquatic (AG, n = 8, Sand (SG, n = 8 and Firm (FG, n = 8. The AG performed PE in an aquatic setting with a depth of ~130 cm. The SG performed PE on a dry sand surface at a depth of 20 cm, and the FG performed PE on a 10-cm-thick wooden surface. Plasma creatine kinase (CK activity, delayed onset muscle soreness (DOMS, knee range of motion (KROM, maximal isometric voluntary contraction (MIVC of the knee extensors, vertical jump (VJ and 10-m sprint were measured before and 24, 48 and 72 h after the PE. Compared to baseline values, FG showed significantly (p < 0.05 greater changes in CK, DOMS, and VJ at 24 until 48 h. The MIVC decreased significantly for the SG and FG at 24 until 48 h post-exercise in comparison to the pre-exercise values. There were no significant (p > 0.05 time or group by time interactions in KROM. In the 10-m sprint, all the treatment groups showed significant (p < 0.05 changes compared to pre-exercise values at 24 h, and there were no significant (p > 0.05 differences between groups. The results indicate that PE in an aquatic setting and on a sand surface induces less muscle damage than on a firm surface. Therefore, training in aquatic conditions and on sand may be beneficial for the improvement of performance, with a concurrently lower risk of muscle damage and soreness.

  15. Differential Effects of Lichens versus Liverworts Epiphylls on Host Leaf Traits in the Tropical Montane Rainforest, Hainan Island, China

    Directory of Open Access Journals (Sweden)

    Lingyan Zhou

    2014-01-01

    Full Text Available Epiphylls widely colonize vascular leaves in moist tropical forests. Understanding the effects of epiphylls on leaf traits of host plants is critical for understanding ecological function of epiphylls. A study was conducted in a rain forest to investigate leaf traits of the host plants Photinia prunifolia colonized with epiphyllous liverworts and foliicolous lichens as well as those of uncolonized leaves. Our results found that the colonization of lichens significantly decreased leaf water content (LWC, chlorophyll (Chl a and a + b content, and Chl a/b of P. prunifolia but increased Chl b content, while that of liverworts did not affect them as a whole. The variations of net photosynthetic rates (Pn among host leaves colonized with different coverage of lichens before or after removal treatment (a treatment to remove epiphylls from leaf surface were greater than that colonized with liverworts. The full cover of lichens induced an increase of light compensation point (LCP by 21% and a decrease of light saturation point (LSP by 54% for their host leaves, whereas that of liverworts displayed contrary effects. Compared with the colonization of liverworts, lichens exhibited more negative effects on the leaf traits of P. prunifolia in different stages of colonization. The results suggest that the responses of host leaf traits to epiphylls are affected by the epiphyllous groups and coverage, which are also crucial factors in assessing ecofunctions of epiphylls in tropical forests.

  16. Differential effects of lichens versus liverworts epiphylls on host leaf traits in the tropical montane rainforest, Hainan Island, China.

    Science.gov (United States)

    Zhou, Lingyan; Liu, Fude; Yang, Wenjie; Liu, Hong; Shao, Hongbo; Wang, Zhongsheng; An, Shuqing

    2014-01-01

    Epiphylls widely colonize vascular leaves in moist tropical forests. Understanding the effects of epiphylls on leaf traits of host plants is critical for understanding ecological function of epiphylls. A study was conducted in a rain forest to investigate leaf traits of the host plants Photinia prunifolia colonized with epiphyllous liverworts and foliicolous lichens as well as those of uncolonized leaves. Our results found that the colonization of lichens significantly decreased leaf water content (LWC), chlorophyll (Chl) a and a + b content, and Chl a/b of P. prunifolia but increased Chl b content, while that of liverworts did not affect them as a whole. The variations of net photosynthetic rates (P n ) among host leaves colonized with different coverage of lichens before or after removal treatment (a treatment to remove epiphylls from leaf surface) were greater than that colonized with liverworts. The full cover of lichens induced an increase of light compensation point (LCP) by 21% and a decrease of light saturation point (LSP) by 54% for their host leaves, whereas that of liverworts displayed contrary effects. Compared with the colonization of liverworts, lichens exhibited more negative effects on the leaf traits of P. prunifolia in different stages of colonization. The results suggest that the responses of host leaf traits to epiphylls are affected by the epiphyllous groups and coverage, which are also crucial factors in assessing ecofunctions of epiphylls in tropical forests.

  17. Different Culture Media Affect Proliferation, Surface Epitope Expression, and Differentiation of Ovine MSC.

    Science.gov (United States)

    Adamzyk, Carina; Emonds, Tanja; Falkenstein, Julia; Tolba, René; Jahnen-Dechent, Wilhelm; Lethaus, Bernd; Neuss, Sabine

    2013-01-01

    Orthopedic implants including engineered bone tissue are commonly tested in sheep. To avoid rejection of heterologous or xenogeneic cells, autologous cells are preferably used, that is, ovine mesenchymal stem cells (oMSC). Unlike human MSC, ovine MSC are not well studied regarding isolation, expansion, and characterization. Here we investigated the impact of culture media composition on growth characteristics, differentiation, and surface antigen expression of oMSC. The culture media varied in fetal calf serum (FCS) content and in the addition of supplements and/or additional epidermal growth factor (EGF). We found that FCS strongly influenced oMSC proliferation and that specific combinations of supplemental factors (MCDB-201, ITS-plus, dexamethasone, and L-ascorbic acid) determined the expression of surface epitopes. We compared two published protocols for oMSC differentiation towards the osteogenic, adipogenic, and chondrogenic fate and found (i) considerable donor to donor variations, (ii) protocol-dependent variations, and (iii) variations resulting from the preculture medium composition. Our results indicate that the isolation and culture of oMSC in different growth media are highly variable regarding oMSC phenotype and behaviour. Furthermore, variations from donor to donor critically influence growth rate, surface marker expression, and differentiation.

  18. Different Culture Media Affect Proliferation, Surface Epitope Expression, and Differentiation of Ovine MSC

    Directory of Open Access Journals (Sweden)

    Carina Adamzyk

    2013-01-01

    Full Text Available Orthopedic implants including engineered bone tissue are commonly tested in sheep. To avoid rejection of heterologous or xenogeneic cells, autologous cells are preferably used, that is, ovine mesenchymal stem cells (oMSC. Unlike human MSC, ovine MSC are not well studied regarding isolation, expansion, and characterization. Here we investigated the impact of culture media composition on growth characteristics, differentiation, and surface antigen expression of oMSC. The culture media varied in fetal calf serum (FCS content and in the addition of supplements and/or additional epidermal growth factor (EGF. We found that FCS strongly influenced oMSC proliferation and that specific combinations of supplemental factors (MCDB-201, ITS-plus, dexamethasone, and L-ascorbic acid determined the expression of surface epitopes. We compared two published protocols for oMSC differentiation towards the osteogenic, adipogenic, and chondrogenic fate and found (i considerable donor to donor variations, (ii protocol-dependent variations, and (iii variations resulting from the preculture medium composition. Our results indicate that the isolation and culture of oMSC in different growth media are highly variable regarding oMSC phenotype and behaviour. Furthermore, variations from donor to donor critically influence growth rate, surface marker expression, and differentiation.

  19. Polarimetric Retrievals of Surface and Cirrus Clouds Properties in the Region Affected by the Deepwater Horizon Oil Spill

    Science.gov (United States)

    Ottaviani, Matteo; Cairns, Brian; Chowdhary, Jacek; Van Diedenhoven, Bastiaan; Knobelspiesse, Kirk; Hostetler, Chris; Ferrare, Rich; Burton, Sharon; Hair, John; Obland, Michael D.; Rogers, Raymond

    2012-01-01

    In 2010, the Goddard Institute for Space Studies (GISS) Research Scanning Polarimeter (RSP) performed several aerial surveys over the region affected by the oil spill caused by the explosion of the Deepwater Horizon offshore platform. The instrument was deployed on the NASA Langley B200 aircraft together with the High Spectral Resolution Lidar (HSRL), which provides information on the distribution of the aerosol layers beneath the aircraft, including an accurate estimate of aerosol optical depth. This work illustrates the merits of polarization measurements in detecting variations of ocean surface properties linked to the presence of an oil slick. In particular, we make use of the degree of linear polarization in the glint region, which is severely affected by variations in the refractive index but insensitive to the waviness of the water surface. Alterations in the surface optical properties are therefore expected to directly affect the polarization response of the RSP channel at 2264 nm, where both molecular and aerosol scattering are negligible and virtually all of the observed signal is generated via Fresnel reflection at the surface. The glint profile at this wavelength is fitted with a model which can optimally estimate refractive index, wind speed and direction, together with aircraft attitude variations affecting the viewing geometry. The retrieved refractive index markedly increases over oil-contaminated waters, while the apparent wind speed is significantly lower than in adjacent uncontaminated areas, suggesting that the slick dampens high-frequency components of the ocean wave spectrum. The constraint on surface reflectance provided by the short-wave infrared channels is a cornerstone of established procedures to retrieve atmospheric aerosol microphysical parameters based on the inversion of the RSP multispectral measurements. This retrieval, which benefits from the ancillary information provided by the HSRL, was in this specific case hampered by

  20. Surface variations affecting human dental enamel studied using nanomechanical and chemical analysis

    Science.gov (United States)

    Dickinson, Michelle Emma

    The enamel surface is the interface between the tooth and its ever changing oral environment. Cavity (caries) formation and extrinsic tooth staining are due, respectively, to degradation of the enamel structure under low pH conditions and interactions between salivary pellicle and dietary elements. Both of these occur at the enamel surface and are caused by the local environment changing the chemistry of the surface. The results can be detrimental to the enamel's mechanical integrity and aesthetics. Incipient carious lesions are the precursor to caries and form due to demineralisation of enamel. These carious lesions are a reversible structure where ions (e.g. Ca2+, F -) can diffuse in (remineralisation) to preserve the tooth's structural integrity. This investigation used controlled in vitro demineralisation and remineralisation to study artificial carious lesion formation and repair. The carious lesions were cross-sectioned and characterised using nanoindentation, electron probe micro-analysis and time of flight secondary ion mass spectrometry. Mechanical and chemical maps showed the carious lesion had a significantly reduced hardness and elastic modulus, and the calcium and phosphate content was lower than in sound enamel. Fluoride based remineralisation treatments gave a new phase (possibly fluorohydroxyapatite) within the lesion with mechanical properties higher than sound enamel. The acquired salivary pellicle is a protein-rich film formed by the physisorption of organic molecules in saliva onto the enamel surface. Its functions include lubrication during mastication and chemical protection. However, pellicle proteins react with dietary elements such as polyphenols (tannins in tea) causing a brown stain. This study has used in vitro dynamic nanoindentation and atomic force microscopy to examine normal and stained pellicles formed in vivo. The effects of polyphenols on the pellicle's mechanical properties and morphology have been studied. It was found that the

  1. The artificial leaf.

    Science.gov (United States)

    Nocera, Daniel G

    2012-05-15

    corner-sharing, head-to-tail dimer. The ability to perform the oxygen-evolving reaction in water at neutral or near-neutral conditions has several consequences for the construction of the artificial leaf. The NiMoZn alloy may be used in place of Pt to generate hydrogen. To stabilize silicon in water, its surface is coated with a conducting metal oxide onto which the Co-OEC may be deposited. The net result is that immersing a triple-junction Si wafer coated with NiMoZn and Co-OEC in water and holding it up to sunlight can effect direct solar energy conversion via water splitting. By constructing a simple, stand-alone device composed of earth-abundant materials, the artificial leaf provides a means for an inexpensive and highly distributed solar-to-fuels system that employs low-cost systems engineering and manufacturing. Through this type of system, solar energy can become a viable energy supply to those in the non-legacy world.

  2. Cell surface alpha 2,6 sialylation affects adhesion of breast carcinoma cells.

    Science.gov (United States)

    Lin, Shaoqiang; Kemmner, Wolfgang; Grigull, Sabine; Schlag, Peter M

    2002-05-15

    Tumor-associated alterations of cell surface glycosylation play a crucial role in the adhesion and metastasis of carcinoma cells. The aim of this study was to examine the effect of alpha 2,6-sialylation on the adhesion properties of breast carcinoma cells. To this end mammary carcinoma cells, MDA-MB-435, were sense-transfected with sialyltransferase ST6Gal-I cDNA or antisense-transfected with a part of the ST6Gal-I sequence. Sense transfectants showed an enhanced ST6Gal-I mRNA expression and enzyme activity and an increased binding of the lectin Sambucus nigra agglutinin (SNA), specific for alpha 2,6-linked sialic acid. Transfection with ST6Gal-I in the antisense direction resulted in less enzyme activity and SNA reactivity. A sense-transfected clone carrying increased amounts of alpha 2,6-linked sialic acid adhered preferentially to collagen IV and showed reduced cell-cell adhesion and enhanced invasion capacity. In contrast, antisense transfection led to less collagen IV adhesion but enhanced homotypic cell-cell adhesion. In another approach, inhibition of ST6Gal-I enzyme activity by application of soluble antisense-oligodeoxynucleotides was studied. Antisense treatment resulted in reduced ST6 mRNA expression and cell surface 2,6-sialylation and significantly decreased collagen IV adhesion. Our results suggest that cell surface alpha 2,6-sialylation contributes to cell-cell and cell-extracellular matrix adhesion of tumor cells. Inhibition of sialytransferase ST6Gal-I by antisense-oligodeoxynucleotides might be a way to reduce the metastatic capacity of carcinoma cells.

  3. The modeling of heat affected zone (HAZ in submerged arc welding (SAW surfacing steel element

    Directory of Open Access Journals (Sweden)

    J. Winczek

    2016-04-01

    Full Text Available In the work the bimodal heat source model in the description of the temperature field is presented. The electric arc was treated physically as one heat source, whose heat was divided: part of the heat is transferred by the direct impact of the electric arc, but another part of the heat is transferred to the weld by the melted material of the electrode. Computations of the temperature field during SAW surfacing of S355 steel element are carried out. The macrographic and metallographic analysis of the weld confirmed the depth and shapes of the fusion line and HAZ defined by the numerical simulation.

  4. A new capture fraction method to map how pumpage affects surface water flow

    Science.gov (United States)

    Leake, S.A.; Reeves, H.W.; Dickinson, J.E.

    2010-01-01

    All groundwater pumped is balanced by removal of water somewhere, initially from storage in the aquifer and later from capture in the form of increase in recharge and decrease in discharge. Capture that results in a loss of water in streams, rivers, and wetlands now is a concern in many parts of the United States. Hydrologists commonly use analytical and numerical approaches to study temporal variations in sources of water to wells for select points of interest. Much can be learned about coupled surface/groundwater systems, however, by looking at the spatial distribution of theoretical capture for select times of interest. Development of maps of capture requires (1) a reasonably well-constructed transient or steady state model of an aquifer with head-dependent flow boundaries representing surface water features or evapotranspiration and (2) an automated procedure to run the model repeatedly and extract results, each time with a well in a different location. This paper presents new methods for simulating and mapping capture using three-dimensional groundwater flow models and presents examples from Arizona, Oregon, and Michigan. Journal compilation ?? 2010 National Ground Water Association. No claim to original US government works.

  5. Bonding to a porcelain surface: Factors affecting the shear bond strength

    Directory of Open Access Journals (Sweden)

    Shishir Singh

    2013-01-01

    Full Text Available Objectives: Bonding to porcelain veneers, crowns or restorations is a major challenge for an orthodontist. A study was undertaken wherein, the shear bond strengths of metal and ceramic brackets on porcelain were compared and the effects of debonding on the debonded surfaces were evaluated. Materials and Methods: A total of 50 acrylic duplicate samples were fabricated from a therapeutically extracted maxillary first premolar, duly prepared for metal crown with porcelain facing. The samples were divided into two equal groups for bonding of metal and ceramic brackets. The shear bond strength of the samples was measured with a universal testing machine. Results: The metal brackets showed shear bond strengths with a mean of 12.21 ± 1.4 MPa, whereas the ceramic brackets displayed shear bond strengths with a mean of 17.45 ± 2.36 MPa. Visual and scanning electron microscope examination revealed multiple failure patterns with more of porcelain fractures in the ceramic brackets group. Conclusion: Bonding of metal and ceramic brackets to porcelain can be achieved with bond strengths comparable to that when bonded to enamel surface. Porcelain fractures are more commonly associated with debonding of ceramic brackets.

  6. Experimental Study of gas-liquid two-phase flow affected by wall surface wettability

    Energy Technology Data Exchange (ETDEWEB)

    Takamasa, T. [Faculty of Marine Technology, Tokyo University of Marine Science and Technology, 2-1-6 Etchujima, Koto, Tokyo 135-8533 (Japan); Hazuku, T. [Faculty of Marine Technology, Tokyo University of Marine Science and Technology, 2-1-6 Etchujima, Koto, Tokyo 135-8533 (Japan)], E-mail: hazuku@kaiyodai.ac.jp; Hibiki, T. [School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, IN 47907-2017 (United States)

    2008-12-15

    To evaluate the effect of wall surface wettability on the characteristics of upward gas-liquid two-phase flow in a vertical pipe, an experimental study was performed using three test pipes: an acrylic pipe, a hydrophilic pipe and a hydrophobic pipe. Basic flow characteristics such as flow patterns, pressure drop and void fraction were measured in these three pipes. In the hydrophilic pipe, a slug to churn flow transition boundary was shifted to a higher gas velocity at a given liquid velocity, whereas a churn to annular flow transition boundary was shifted to a lower gas velocity at a given liquid velocity. In the hydrophobic pipe, an inverted-churn flow regime was observed in the region where the churn flow regime was observed in the acrylic pipe, while a droplet flow regime was observed in the region where an annular flow regime was observed in the acrylic pipe. At a high gas flow rate, the mean void fraction in the hydrophobic pipe was higher than in the acrylic pipe. The effect of surface wettability on frictional pressure loss was confirmed to be insignificant under the present experimental conditions.

  7. Is there an optimal topographical surface in nano-scale affecting protein adsorption and cell behaviors? Part II

    Energy Technology Data Exchange (ETDEWEB)

    Wang Huajie, E-mail: wanghuajie972001@163.com; Sun Yuanyuan; Cao Ying, E-mail: caoying1130@sina.com; Wang Kui; Yang Lin [Henan Normal University, College of Chemistry and Environmental Science (China); Zhang Yidong; Zheng Zhi [Xuchang University, Institute of Surface Micro and Nano Materials (China)

    2012-05-15

    Although nano-structured surfaces exhibit superior biological activities to the smooth or micro-structured surfaces, whether there is an optimal topographical surface in nano-scale affecting protein adsorption and cell behaviors is still controversial. In this study, porous aluminum oxide membranes with different pore sizes ranging from 25 to 120 nm were prepared by the anodic oxidation technique. The surface morphology, topography and wettability were analyzed by scanning electron microscope, atomic force microscope and water contact angle measurement, respectively. The results indicated that the synergistic action of the nano-topography structure and hydrophilic/hydrophobic properties resulted in a highest protein adsorption on the aluminum oxide membrane with 80 nm pore size. Additionally, the morphological, metabolic and cell counting methods showed that cells had different sensitivity to porous aluminum oxide membranes with different surface features. Furthermore, this sensitivity was cell type dependent. The optimal pore size of aluminum oxide membranes for cell growth was 80 nm for PC12 cells and 50 nm for NIH 3T3 cells.

  8. N-acetyl-L-cysteine affects growth, extracellular polysaccharide production, and bacterial biofilm formation on solid surfaces.

    Science.gov (United States)

    Olofsson, Ann-Cathrin; Hermansson, Malte; Elwing, Hans

    2003-08-01

    N-Acetyl-L-cysteine (NAC) is used in medical treatment of patients with chronic bronchitis. The positive effects of NAC treatment have primarily been attributed to the mucus-dissolving properties of NAC, as well as its ability to decrease biofilm formation, which reduces bacterial infections. Our results suggest that NAC also may be an interesting candidate for use as an agent to reduce and prevent biofilm formation on stainless steel surfaces in environments typical of paper mill plants. Using 10 different bacterial strains isolated from a paper mill, we found that the mode of action of NAC is chemical, as well as biological, in the case of bacterial adhesion to stainless steel surfaces. The initial adhesion of bacteria is dependent on the wettability of the substratum. NAC was shown to bind to stainless steel, increasing the wettability of the surface. Moreover, NAC decreased bacterial adhesion and even detached bacteria that were adhering to stainless steel surfaces. Growth of various bacteria, as monocultures or in a multispecies community, was inhibited at different concentrations of NAC. We also found that there was no detectable degradation of extracellular polysaccharides (EPS) by NAC, indicating that NAC reduced the production of EPS, in most bacteria tested, even at concentrations at which growth was not affected. Altogether, the presence of NAC changes the texture of the biofilm formed and makes NAC an interesting candidate for use as a general inhibitor of formation of bacterial biofilms on stainless steel surfaces.

  9. The Heat and Mass Transfer Analysis of a Leaf

    Institute of Scientific and Technical Information of China (English)

    Hong Ye; Zhi Yuan; Shuanqin Zhang

    2013-01-01

    Understanding the heat and mass transfer processes of plant leaves is essential for plant bionic engineering.A general thermophysical model was established for a plant leaf with particular emphasis on the transpiration process.The model was verified by the field measured stomatal resistance and temperature of a camphor leaf.A dynamical simulation revealed that diurnal transpiration water consumption is dominated by the solar irradiance and the day-average temperature of the leaf is dominated by the ambient air temperature; transpiration plays an important role in the cooling of the leaf,in average it could dissipate around 32.9% of the total solar energy absorbed by the leaf in summer.To imitate the thermal infared characteristic of the real leaf,the up surface of the bionic leaf must have emissivity and solar absorptivity close to those of a real leaf and its shape and surface roughness must be similar to those of the real leaf.The key point is that the bionic leaf must be able to evaporate water to simulate the transpiration of a plant leaf,appropriate adsorbent can be used to realize this function.

  10. Losses of leaf area owing to herbivory and early senescence in three tree species along a winter temperature gradient

    Science.gov (United States)

    González-Zurdo, P.; Escudero, A.; Nuñez, R.; Mediavilla, S.

    2016-11-01

    In temperate climates, evergreen leaves have to survive throughout low temperature winter periods. Freezing and chilling injuries can lead to accelerated senescence of part of the leaf surface, which contributes to a reduction of the lifespan of the photosynthetic machinery and of leaf lifetime carbon gain. Low temperatures are also associated with changes in foliar chemistry and morphology that affect consumption by herbivores. Therefore, the severity of foliar area losses caused by accelerated senescence and herbivory can change along winter temperature gradients. The aim of this study is to analyse such responses in the leaves of three evergreen species ( Quercus ilex, Q. suber and Pinus pinaster) along a climatic gradient. The leaves of all three species presented increased leaf mass per area (LMA) and higher concentrations of structural carbohydrates in cooler areas. Only the two oak species showed visible symptoms of damage caused by herbivory, this being less intense at the coldest sites. The leaves of all three species presented chlorotic and necrotic spots that increased in size with leaf age. The foliar surface affected by chlorosis and necrosis was larger at the sites with the coldest winters. Therefore, the effects of the winter cold on the lifespan of the photosynthetic machinery were contradictory: losses of leaf area due to accelerated senescence increased, but there was a decrease in losses caused by herbivory. The final consequences for carbon assimilation strongly depend on the exact timing of the appearance of the damage resulting from low temperature and grazing by herbivores.

  11. The miscibility of milk sphingomyelin and cholesterol is affected by temperature and surface pressure in mixed Langmuir monolayers.

    Science.gov (United States)

    Cheng, Ken; Ropers, Marie-Hélène; Lopez, Christelle

    2017-06-01

    The miscibility of milk sphingomyelin (milk-SM) and cholesterol was investigated in this study. The effect of different physical states of milk-SM on its interactions with cholesterol was determined by the recording of isotherms of compression of Langmuir films for temperatures above and below the gel to Lα phase transition of milk-SM (Tm∼34°C). For T=15°CTm, the milk-SM molecules were in a LE phase regardless of the surface pressure applied. A phase diagram pressure - milk-SM/cholesterol composition was established. This study demonstrated that both temperature and surface pressure affected the miscibility between the milk-SM and cholesterol. The strongest attractive forces (i.e. condensing effect) were identified for 30mol% cholesterol when the milk-SM was in the LE phase state.

  12. Manufacturing lot affects polyethylene tibial insert volume, thickness, and surface geometry.

    Science.gov (United States)

    Teeter, Matthew G; Milner, Jaques S; MacDonald, Steven J; Naudie, Douglas D R

    2013-08-01

    To perform wear measurements on retrieved joint replacement implants, a reference geometry of the implant's original state is required. Since implants are rarely individually scanned before implantation, a different, new implant of the same kind and size is frequently used. However, due to manufacturing variability, errors may be introduced into these measurements, as the dimensions between the retrieved and reference components may not be exactly the same. The hypothesis of this study was that new polyethylene tibial inserts from different manufacturing lots would demonstrate greater variability than those from the same lot. In total, 12 new tibial inserts of the same model and size were obtained, 5 from the same lot and the remainder from different lots. The geometry of each tibial insert was obtained using microcomputed tomography. Measurements of tibial insert volume, thickness, and three-dimensional surface deviations were obtained and compared between tibial inserts from the same and different manufacturing lots. Greater variability was found for the tibial inserts from different manufacturing lots for all types of measurements, including a fourfold difference in volume variability (p manufacturing lots for use as the reference geometry.

  13. Regression analysis in modeling of air surface temperature and factors affecting its value in Peninsular Malaysia

    Science.gov (United States)

    Rajab, Jasim Mohammed; Jafri, Mohd. Zubir Mat; Lim, Hwee San; Abdullah, Khiruddin

    2012-10-01

    This study encompasses air surface temperature (AST) modeling in the lower atmosphere. Data of four atmosphere pollutant gases (CO, O3, CH4, and H2O) dataset, retrieved from the National Aeronautics and Space Administration Atmospheric Infrared Sounder (AIRS), from 2003 to 2008 was employed to develop a model to predict AST value in the Malaysian peninsula using the multiple regression method. For the entire period, the pollutants were highly correlated (R=0.821) with predicted AST. Comparisons among five stations in 2009 showed close agreement between the predicted AST and the observed AST from AIRS, especially in the southwest monsoon (SWM) season, within 1.3 K, and for in situ data, within 1 to 2 K. The validation results of AST with AST from AIRS showed high correlation coefficient (R=0.845 to 0.918), indicating the model's efficiency and accuracy. Statistical analysis in terms of β showed that H2O (0.565 to 1.746) tended to contribute significantly to high AST values during the northeast monsoon season. Generally, these results clearly indicate the advantage of using the satellite AIRS data and a correlation analysis study to investigate the impact of atmospheric greenhouse gases on AST over the Malaysian peninsula. A model was developed that is capable of retrieving the Malaysian peninsulan AST in all weather conditions, with total uncertainties ranging between 1 and 2 K.

  14. Water chemistry of surface waters affected by the Fourmile Canyon wildfire, Colorado, 2010-2011

    Science.gov (United States)

    McCleskey, R. Blaine; Writer, Jeffrey H.; Murphy, Sheila F.

    2012-01-01

    In September 2010, the Fourmile Canyon fire burned about 23 percent of the Fourmile Creek watershed in Boulder County, Colo. Water-quality sampling of Fourmile Creek began within a month after the wildfire to assess its effects on surface-water chemistry. Water samples were collected from five sites along Fourmile Creek (above, within, and below the burned area) monthly during base flow, twice weekly during snowmelt runoff, and at higher frequencies during storm events. Stream discharge was also monitored. Water-quality samples were collected less frequently from an additional 6 sites on Fourmile Creek, from 11 tributaries or other inputs, and from 3 sites along Boulder Creek. The pH, electrical conductivity, temperature, specific ultraviolet absorbance, total suspended solids, and concentrations (dissolved and total) of major cations (calcium, magnesium, sodium, and potassium), anions (chloride, sulfate, alkalinity, fluoride, and bromide), nutrients (nitrate, ammonium, and phosphorus), trace metals (aluminum, arsenic, boron, barium, beryllium, cadmium, cobalt, chromium, copper, iron, mercury, lithium, manganese, molybdenum, nickel, lead, rubidium, antimony, selenium, strontium, vanadium, and zinc), and dissolved organic carbon are here reported for 436 samples collected during 2010 and 2011.

  15. Quantitative anatomy of grapevine (Vitis L. leaf blade

    Directory of Open Access Journals (Sweden)

    Valentine S. Codreanu

    2013-04-01

    Full Text Available Current investigations were conducted to clarify the features of grapevine which are adaptive to drought and can be used in selection and introduction of VitisL. There are determined biometric values of 21 morpho-anatomic characters of leaf blade for 10 species of grapevine, 10 cultivars of V. viniferaL. and 10 distant hybrids V. vinifera× Muscadinia rotundifoliaMichx. As a result of this study 6 leaf blade quantitative characters which determine relative grapevine drought resistance were described. The most drought resistant species, sorts and hybrids of grapevine are that which have: a greater average thickness of leaf blade; b smaller surface (average area of leaf blade; c less ratio between average area and average volume of dried leaf blade; d greater mass of dried leaf blade; e higher degrees of the leaf succulence and sclerophylly.

  16. Modeling leaf venation morphogenesis

    CERN Document Server

    Laguna, M F; Jagla, E A

    2007-01-01

    We explore the possibility that the formation of leaf venation patterns is driven by mechanical instabilities in the growing leaf. In contrast to the prevalent canalization hypothesis based on polar auxin transport, mechanical instabilities lead very naturally to hierarchical patterns with an abundant number of closed loops as they exists in almost every leaf venation. We propose a continuum model where the vein formation is driven by a mechanical collapse of the mesophyll layer in the growing leaf, and present a numerical study of this model using a phase field approach. The results show the same qualitative features as real venation patterns and, furthermore, have the same statistical properties.

  17. Erosive cola-based drinks affect the bonding to enamel surface: an in vitro study

    Directory of Open Access Journals (Sweden)

    Leslie Caroll CASAS-APAYCO

    2014-10-01

    Full Text Available Objective: This study aimed to assess the impact of in vitro erosion provoked by different cola-based drinks (Coke types, associated or not with toothbrushing, to bonding to enamel. Material and methods: Forty-six bovine enamel specimens were prepared and randomly assigned into seven groups (N=8: C- Control (neither eroded nor abraded, ERO-RC: 3x/1-minute immersion in Regular Coke (RC, ERO-LC: 3x/1-minute immersion in Light Coke (LC, ERO-ZC: 3x/1-minute immersion in Zero Coke (ZC and three other eroded groups, subsequently abraded for 1-minute toothbrushing (EROAB-RC, EROAB-LC and EROAB-ZC, respectively. After challenges, they were stored overnight in artificial saliva for a total of 24 hours and restored with Adper Single Bond 2/Filtek Z350. Buildup coronal surfaces were cut in 1 mm2 -specimens and subjected to a microtensile test. Data were statistically analyzed by two-way ANOVA/Bonferroni tests (α=0.05. Failure modes were assessed by optical microscopy (X40. The Interface of the restorations were observed using Confocal Laser Scanning Microscopy (CLSM. Results: All tested cola-based drinks significantly reduced the bond strength, which was also observed in the analyses of interfaces. Toothbrushing did not have any impact on the bond strength. CLSM showed that except for Zero Coke, all eroded specimens resulted in irregular hybrid layer formation. Conclusions: All cola-based drinks reduced the bond strength. Different patterns of hybrid layers were obtained revealing their impact, except for ZC.

  18. Quantum dots affect expression of CD133 surface antigen in melanoma cells

    Directory of Open Access Journals (Sweden)

    Steponkiene S

    2011-10-01

    Full Text Available Simona Steponkiene1-3, Simona Kavaliauskiene1, Rasa Purviniene4, Ricardas Rotomskis3,5, Petras Juzenas11Department of Radiation Biology, Institute for Cancer Research, Oslo University Hospital, Radiumhospital, Oslo, Norway; 2Faculty of Natural Sciences, Vilnius University, Vilnius, Lithuania; 3Biomedical Physics Laboratory of Oncology Institute, Vilnius University, Vilnius, Lithuania; 4Immunology Laboratory of Oncology Institute, Vilnius University, Vilnius, Lithuania; 5Biophotonics Laboratory, Laser Research Center, Vilnius University, Vilnius, LithuaniaBackground: In novel treatment approaches, therapeutics should be designed to target cancer stem cells (CSCs. Quantum dots (QDs are a promising new tool in fighting against cancer. However, little is known about accumulation and cytotoxicity of QDs in CSCs.Methods: Accumulation and cytotoxicity of CdTe-MPA (mercaptopropionic acid QDs in CSCs were assessed using flow cytometry and fluorescence-activated cell sorting techniques as well as a colorimetric cell viability assay.Results: We investigated the expression of two cell surface-associated glycoproteins, CD44 and CD133, in four different cancer cell lines (glioblastoma, melanoma, pancreatic, and prostate adenocarcinoma. Only the melanoma cells were positive to both markers of CD44 and CD133, whereas the other cells were only CD44-positive. The QDs accumulated to a similar extent in all subpopulations of the melanoma cells. The phenotypical response after QD treatment was compared with the response after ionizing radiation treatment. The percentage of the CD44high-CD133high subpopulation decreased from 72% to 55%–58% for both treatments. The stem-like subpopulation CD44highCD133low/- increased from 26%–28% in the untreated melanoma cells to 36%–40% for both treatments.Conclusion: Treatment of melanoma cells with QDs results in an increase of stem-like cell subpopulations. The changes in phenotype distribution of the melanoma cells after

  19. Top predator absence enhances leaf breakdown in an intermittent stream.

    Science.gov (United States)

    Rodríguez-Lozano, Pablo; Rieradevall, Maria; Prat, Narcís

    2016-12-01

    Current biodiversity loss is characterized by the extinction of top predators, but small-bodied freshwater fish are often overlooked in research and conservation management even when threatened because they usually lack commercial value. Therefore, the ecosystem impacts of their possible loss remain mostly unknown. We assessed whether the presence/absence of an endangered predatory fish (Barbus meridionalis (A. Risso, 1827)) in an intermittent stream affects leaf fungal biomass and leaf quality (i.e. leaf carbon:nitrogen ratio and leaf toughness), macroinvertebrate assemblages colonizing leaf packs, and leaf breakdown rates. We conducted a leaf bag experiment comparing a control reach with a population of B. meridionalis with an adjacent upstream fishless reach. In the fishless reach, leaf fungal biomass and microbially mediated breakdown rate were lower compared to the control reach. This was probably caused by the lack of the bottom-up stimulation through nutrient recycling by fish. Shredders and scrapers were found at higher abundance and biomass in the fishless compared to the control reach, and the whole macroinvertebrate community composition changed with fish absence. Consequently, macroinvertebrate mediated leaf breakdown was faster in the fishless than in the control reach, not only compensating for the lower microbially mediated leaf breakdown in the fishless reach, but accelerating the overall leaf breakdown rate. Our study contributes to understand the potential cascading effects produced by the extirpation of endangered small-bodied fish.

  20. Acetylation of cell wall is required for structural integrity of the leaf surface and exerts a global impact on plant stress responses

    DEFF Research Database (Denmark)

    Nafisi, Majse; Stranne, Maria; Fimognari, Lorenzo;

    2015-01-01

    The epidermis on leaves protects plants from pathogen invasion and provides a waterproof barrier. It consists of a layer of cells that is surrounded by thick cell walls, which are partially impregnated by highly hydrophobic cuticular components. We show that the Arabidopsis T-DNA insertion mutants...... to abiotic stress, particularly detoxification of reactive oxygen species and defense against microbial pathogens (e.g., lipid transfer proteins, peroxidases). In accordance, peroxidase activities were found to be elevated in rwa2 as compared to the wild type. These results indicate that cell wall...... acetylation is essential for maintaining the structural integrity of leaf epidermis, and that reduction of cell wall acetylation leads to global stress responses in Arabidopsis....

  1. Different Organization of Type I Collagen Immobilized on Silanized and Nonsilanized Titanium Surfaces Affects Fibroblast Adhesion and Fibronectin Secretion.

    Science.gov (United States)

    Marín-Pareja, Nathalia; Cantini, Marco; González-García, Cristina; Salvagni, Emiliano; Salmerón-Sánchez, Manuel; Ginebra, Maria-Pau

    2015-09-23

    Silanization has emerged in recent years as a way to obtain a stronger and more stable attachment of biomolecules to metallic substrates. However, its impact on protein conformation, a key aspect that influences cell response, has hardly been studied. In this work, we analyzed by atomic force microscopy (AFM) the distribution and conformation of type I collagen on plasma-treated surfaces before and after silanization. Subsequently, we investigated the effect of the different collagen conformations on fibroblasts adhesion and fibronectin secretion by immunofluorescence analyses. Two different organosilanes were used on plasma-treated titanium surfaces, either 3-chloropropyl-triethoxy-silane (CPTES) or 3-glycidyloxypropyl-triethoxy-silane (GPTES). The properties and amount of the adsorbed collagen were assessed by contact angle, X-ray photoelectron spectroscopy, optical waveguide lightmode spectroscopy, and AFM. AFM studies revealed different conformations of type I collagen depending on the silane employed. Collagen was organized in fibrillar networks over very hydrophilic (plasma treated titanium) or hydrophobic (silanized with CPTES) surfaces, the latter forming little globules with a beads-on-a-string appearance, whereas over surfaces presenting an intermediate hydrophobic character (silanized with GPTES), collagen was organized into clusters with a size increasing at higher protein concentration in solution. Cell response was strongly affected by collagen conformation, especially at low collagen density. The samples exhibiting collagen organized in globular clusters (GPTES-functionalized samples) favored a faster and better fibroblast adhesion as well as better cell spreading, focal adhesions formation, and more pronounced fibronectin fibrillogenesis. In contrast, when a certain protein concentration was reached at the material surface, the effect of collagen conformation was masked, and similar fibroblast response was observed in all samples.

  2. 甘南亚高寒草甸金露梅叶片氮磷化学计量学动态%Leaf nitrogen and phosphorus stoichiometry in Potentilla fruticosa L.affected by internal and external factors in the subalpine in Gannan

    Institute of Scientific and Technical Information of China (English)

    赵君; 张仁懿; 李新娥; 陈凌云; 王刚

    2011-01-01

    Leaf N and P stoichiometry of Potentilla fruticosa L. were studied under external factors (different nutrients level) and internal factors (with and without reproduction). The results showed that there was a significant effect of fertilization on leaf w(N) and w(P); leaf w(N) was 17.8, 18.9, 20.1, 22.6 mg/g, leaf w(P)was 1.92, 2.05, 2.19, 2.58 mg/g after fertilization (0, 40, 80, 120 g/m2 NH4H2PO4) respectively; but there was no significant effect of fertilization on w(N) :w(P) ratios. Reproduction significantly decreased leaf N content while the impact on P content was weak. The effect of external and internal factors on the leaf stoichiometry of Potentilla fruticosa L. was different. Fertilization affected leaf N and P content significantly while it did not affect w(N): w(P) significantly. Reproduction decreased leaf w(N) and leaf w(N): w(P) significantly. Leaf w(N): w(P)of Potentilla fruticosa L. showed a convergence and differentiation under external and internal factors.%通过甘南地区金露梅的研究,以营养元素的不同水平供给为外部驱动因素,有无繁殖过程为内部因素,比较分析了金露梅叶片氮磷化学计量学的变化特征.研究结果表明:施肥显著影响了叶片的w(N)和w(P),施肥后叶片的w(N)依次为17.8,18.9,20.1,22.6 mg/g,w(P)依次为1.92,2.05,2.19,2.58 mg/g,但施肥对w(N):w(P)的影响不显著.繁殖显著降低了叶片的w(N)和w(N):w(P),而对w(P)影响不显著.外部和内部因素对金露梅叶片的化学计量学的影响不相同.不同的施肥水平显著影响金露梅叶片的w(N)和w(P),而对w(N):w(P)影响不显著.证明繁殖过程导致了氮的大量消耗和w(N):w(P)的显著降低.金露梅在内外因素的影响下分别表现了w(N):w(P)的趋同和分异.

  3. Investigating the Alometric Relationships between Leaf Area and Some of Vegetative Characteristics in SC704 Corn Hybrid

    Directory of Open Access Journals (Sweden)

    E Zeinali

    2016-10-01

    Full Text Available Introduction Since the leaves are the main source of production of photosynthetic substances in plants, dry matter production and crop yield potential is largely dependent on the leaf surface, and many environmental changes affect growth and yield through changes in leaf area. Hence, green leaf area per plant and leaf area index is measured in almost all studies of crop physiology to understand the mechanism of yield alteration. However, measurement of leaf area compared with the other traits such as plant height and total plant dry weight is very difficult, need to precision instruments and spend more time and cost. Therefore, according to the allometric relationships in plants, extensive studies were done to find the relationship between leaf area and the other plant traits that their measurement is easier, faster and cheaper, and does not require expensive equipment. Using these relationships will be used to estimate plant leaf area with acceptable accuracy without measuring. Plant traits that have high correlation with leaf area and usually use to estimate the plant leaf area are the number of leaves or nodes per main stem, plant height, leaf dry weight and dry weight of vegetative parts of the plant. Allometric equations was used successfully to calculate leaf area for various crops such as cotton, wheat, chickpea, faba bean, peanuts, soybean and sweet sorghum. This study was conducted to obtain the allometric relationships between green leaf area (cm2 per plant with number of leaves or nodes per main stem, plant height, green leaf dry weight and dry weight of vegetative parts of the plant (gram per plant, and investigating the effect of plant density and planting date on these relationships in SC704 corn (Zea mays L. hybrid. Materials and Methods This study was conducted at Gorgan University of Agricultural Sciences and Natural Resources farm located at latitude 36 o 51’ N, longitude 54 o27’ E and altitude of 13 meters above sea level

  4. A framework for consistent estimation of leaf area index, fraction of absorbed photosynthetically active radiation, and surface albedo from MODIS time-series data

    DEFF Research Database (Denmark)

    Xiao, Zhiqiang; Liang, Shunlin; Wang, Jindi

    2015-01-01

    Currently available land-surface parameter products are generated using parameter-specific algorithms from various satellite data and contain several inconsistencies. This paper developed a new data assimilation framework for consistent estimation of multiple land-surface parameters from time...... model and the MODIS surface reflectance data. The estimated LAI values were then input into the ACRM to calculate the surface albedo and the fraction of absorbed photosynthetically active radiation (FAPAR). For snow-covered areas, the surface albedo was calculated as the underlying vegetation canopy...

  5. Summer (sub-arctic) versus winter (sub-tropical) production affects on spinach leaf bio-nutrients: Vitamins (C, E, Folate, K1, provitamin A), lutein, phenolics, and antioxidants

    Science.gov (United States)

    Comparison of spinach (Spinacia oleracea L.) cultivars Lazio and Samish grown during the summer solstice in the sub-arctic versus the winter solstice in the sub-tropics provided insight into interactions between plant environment (day length, light intensity, ambient temperatures), cultivar and leaf...

  6. A Study of Sugarcane Leaf-Removal Machinery during Harvest

    Directory of Open Access Journals (Sweden)

    Sopa Cansee

    2010-01-01

    Full Text Available Problem statement: Sugarcane leaf-removing tools could help speed up sugarcane harvest and reduce contamination. Moreover, leaf-removal machinery can solve the problems of sugarcane burning and workers can increase sugarcane harvest production too. The purpose of this research was to study the use of leaf-removal machinery in the post-harvest production of sugarcane to reduce harvest production time and contaminant. Approach: This study focused on the LK92-11 variety of sugarcane having a harvesting period of 12 months, a density of 9,387 stems/rai and could produce 14.01 tons/rai including cane top and, leaves and leaf sheaths of 1675.2 and 180 kg/rai. Sugarcane leaf-removal machinery was applied to a small engine power from a grass-cutting machine. A rotate dish applied 4 different materials, tendon string, soft wire, medium wire and sling for sugarcane leaf-removing. The machine was operated at a constant speed. The efficiency of the sugarcane leaf-removal machinery indicated the capacity of sugarcane leaf-removing by area and operation time. Results: The quantity of leaves and leaf sheaths affect the speed of harvest production. Moreover, leaves and leaf sheaths increase the waste material in production and also contaminate the sugar and the sugar production system with clay, sand, and mud from the fields. Traditional methods for sugarcane harvest without removing leaf took 37 h/rai to complete, but sugarcane leaf-removing could reduce the sugarcane harvest process to 11.4 h/rai. Conclusion: The material of the blades in de-leafing machine is crucial to the efficiency of harvest production time. Blades made from poor materials can cause tangling and clogging in the rotator dish, which increases maintenance time. Further developments in sugarcane leaf removal systems will create dramatic improvement in sugarcane production.

  7. Acquired changes in stomatal characteristics in response to ozone during plant growth and leaf development of bush beans (Phaseolus vulgaris L.) indicate phenotypic plasticity

    Energy Technology Data Exchange (ETDEWEB)

    Elagoez, Vahram [Plant Biology Graduate Program, University of Massachusetts, Amherst, MA 01003 (United States)]. E-mail: velagoz@nsm.umass.edu; Han, Susan S. [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Amherst, MA 01003 (United States); Manning, William J. [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Amherst, MA 01003 (United States)

    2006-04-15

    Bush bean (Phaseolus vulgaris L.) lines 'S156' (O{sub 3}-sensitive)/'R123' (O{sub 3}-tolerant) and cultivars 'BBL 290' (O{sub 3}-sensitive)/'BBL 274' (O{sub 3}-tolerant) were used to study the effects of O{sub 3} on stomatal conductance (g {sub s}), density, and aperture size on leaf and pod surfaces with the objective of establishing links between the degree of plant sensitivity to O{sub 3} and plasticity of stomatal properties in response to O{sub 3}. Studies in open-top chambers (OTCs) and in continuously stirred tank reactors (CSTRs) established a clear relationship between plant developmental stages, degrees of O{sub 3} sensitivity and g {sub s}: while 'S156' had higher g {sub s} rates than 'R123' earlier in development, similar differences between 'BBL 290' and 'BBL 274' were observed at later stages. G {sub s} rates on the abaxial leaf surfaces of 'S156' and 'BBL 290', accompanied by low leaf temperatures, were significantly higher than their O{sub 3}-tolerant counterparts. Exposure to O{sub 3} in CSTRs had greater and more consistent impacts on both stomatal densities and aperture sizes of O{sub 3}-sensitive cultivars. Stomatal densities were highest on the abaxial leaf surfaces of 'S156' and 'BBL 290' at higher O{sub 3} concentrations (60 ppb), but the largest aperture sizes were recorded on the adaxial leaf surfaces at moderate O{sub 3} concentrations (30 ppb). Exposure to O{sub 3} eliminated aperture size differences on the adaxial leaf surfaces between sensitive and tolerant cultivars. Regardless of sensitivity to O{sub 3} and treatment regimes, the smallest aperture sizes and highest stomatal densities were found on the abaxial leaf surface. Our studies showed that O{sub 3} has the potential to affect stomatal plasticity and confirmed the presence of different control mechanisms for stomatal development on each leaf surface. This

  8. The plasma membrane aquaporin NtAQP1 is a key component of the leaf unfolding mechanism in tobacco

    NARCIS (Netherlands)

    Siefritz, F.; Otto, B.; Beinert, G.P.; Krol, van der A.R.; Kaldenhoff, R.

    2004-01-01

    Epinastic leaf movement of tobacco is based on differential growth of the upper and lower leaf surface and is distinct from the motor organ-driven mechanism of nyctinastic leaf movement of, for example, mimosa species. The epinastic leaf movement of tobacco is observed not only under diurnal light r

  9. Leaf morphological effects predict effective path length and enrichment of 18O in leaf water of different Eucalyptus species

    Science.gov (United States)

    Kahmen, A.; Merchant, A.; Callister, A.; Dawson, T. E.; Arndt, S. K.

    2006-12-01

    Stable isotopes have been a valuable tool to study water or carbon fluxes of plants and ecosystems. In particular oxygen isotopes (δ18O) in leaf water or plant organic material are now beginning to be established as a simple and integrative measure for plant - water relations. Current δ18O models, however, are still limited in their application to a broad range of different species and ecosystems. It remains for example unclear, if species-specific effects such as different leaf morphologies need to be included in the models for a precise understanding and prediction of δ18O signals. In a common garden experiment (Currency Creek Arboretum, South Australia), where over 900 different Eucalyptus species are cultivated in four replicates, we tested effects of leaf morphology and anatomy on δ18O signals in leaf water of 25 different species. In particular, we determined for all species enrichment in 18O of mean lamina leaf water above source water (Δ18O) as related to leaf physiology as well as leaf thickness, leaf area, specific leaf area and weight and selected anatomical properties. Our data revealed that diurnal Δ18O in leaf water at steady state was significantly different among the investigated species and with differences up to 10% at midday. Fitting factors (effective path length) of leaf water Δ18O models were also significantly different among the investigated species and were highly affected by species-specific morphological parameters. For example, leaf area explained a high percentage of the differences in effective path length observed among the investigated species. Our data suggest that leaf water δ18O can act as powerful tool to estimate plant - water relations in comparative studies but that additional leaf morphological parameters need to be considered in existing δ18O models for a better interpretation of the observed δ18O signals.

  10. 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.

  11. Leaf growth is conformal

    Science.gov (United States)

    Alim, Karen; Armon, Shahaf; Shraiman, Boris I.; Boudaoud, Arezki

    2016-10-01

    Growth pattern dynamics lie at the heart of morphogenesis. Here, we investigate the growth of plant leaves. We compute the conformal transformation that maps the contour of a leaf at a given stage onto the contour of the same leaf at a later stage. Based on the mapping we predict the local displacement field in the leaf blade and find it to agree with the experimentally measured displacement field to 92%. This approach is applicable to any two-dimensional system with locally isotropic growth, enabling the deduction of the whole growth field just from observation of the tissue contour.

  12. Leaf growth is conformal

    CERN Document Server

    Alim, Karen; Shraiman, Boris I; Boudaoud, Arezki

    2016-01-01

    Growth pattern dynamics lie at the heart of morphogenesis. Here, we investigate the growth of plant leaves. We compute the conformal transformation that maps the contour of a leaf at a given stage onto the contour of the same leaf at a later stage. Based on the mapping we predict the local displacement field in the leaf blade and find it to agree with the experimentally measured displacement field to 92%. This approach is applicable to any two-dimensional system with locally isotropic growth, enabling the deduction of the whole growth field just from observation of the tissue contour.

  13. The emission of volatile compounds from leaf litter

    NARCIS (Netherlands)

    Derendorp, L.

    2012-01-01

    Leaf litter is available at the Earth’s surface in large quantities. During the decomposition of leaf litter, volatile compounds can be released into the atmosphere, where they potentially influence local air quality, atmospheric chemistry or the global climate. In this thesis the focus was on the e

  14. Carbon redistribution during interrill erosion in subtropical forests: Effects of leaf litter diversity and soil fauna

    Science.gov (United States)

    Goebes, Philipp; Seitz, Steffen; Kühn, Peter; Scholten, Thomas

    2016-04-01

    Soil erosion is crucial for degradation of carbon (C) from their pools in the soil. If C of the eroded sediment and runoff are not only related to soil pools but also resulting additively from decomposition of litter cover, the system gets more complex. The role of these amounts for C cycling in a forest environment is not yet known properly and thus, the aim of this study was to investigate the role of leaf litter diversity, litter cover and soil fauna on C redistribution during interrill erosion. We established 96 runoff plots that were deployed with seven domestic leaf litter species resulting in none species (bare ground), 1-species, 2-species and 4-species mixtures. Every second runoff plot was equipped with a fauna extinction feature to investigate the role of soil meso- and macrofauna. Erosion processes were initiated using a rainfall simulator at two time steps (summer 2012 and autumn 2012) to investigate the role of leaf litter decomposition on C redistribution. C fluxes during 20 min rainfall simulation were 99.13 ± 94.98 g/m². C fluxes and C contents both were affected by soil fauna. C fluxes were higher with presence of soil fauna due to loosening and slackening of the soil surface rather than due to faster decomposition of leaves. In contrast, C contents were higher in the absence of soil fauna possibly resulting from a missing dilution effect in the top soil layer. Leaf litter diversity did not affect C fluxes, but indirectly affected C contents as it increased the soil fauna effect with higher leaf litter diversity due to superior food supply. Initial C contents in the soil mainly determined those of the eroded sediment. For future research, it will be essential to introduce a long-term decomposition experiment to get further insights into the processes of C redistribution.

  15. The leaf surface strucure of the species from the subgenus Sedum of the genus Sedum L. (Crassulaceae DC. from the protected soil collections of A.V. Fomin Botanical Garden

    Directory of Open Access Journals (Sweden)

    Mykola V. Yatsenko

    2013-04-01

    Full Text Available By means of light and scanning electron microscopy (SEM the structure of leaf ’s epidermis of 8 species of genus SedumL. was investigated. A number of common (amphistomatics, anisocytic type of stomatal complex, strum cuticle and different signs have been revealed in the structure of the leaf ’s tissue. The results acquired on the basis of micromorphology of a leaf ’s epidermis can be used in the taxonomy of the investigated Sedumspecies.

  16. Phyllotaxis involves auxin drainage through leaf primordia

    DEFF Research Database (Denmark)

    Deb, Yamini; Marti, Dominik; Frenz, Martin;

    2015-01-01

    of phyllotaxis invoke the accumulation of auxin at leaf initials and removal of auxin through their developing vascular strand, the midvein. We have developed a precise microsurgical tool to ablate the midvein at high spatial and temporal resolution in order to test its function in leaf formation and phyllotaxis...... and to an increase in their width. Phyllotaxis was transiently affected after midvein ablations, but readjusted after two plastochrons. These results indicate that the developing midvein is involved in the basipetal transport of auxin through young primordia, which contributes to phyllotactic spacing and stability...

  17. International Studies of Hazardous Groundwater/Surface Water Exchange in the Volcanic Eruption and Tsunami Affected Areas of Kamchatka

    Science.gov (United States)

    Kontar, Y. A.; Gusiakov, V. K.; Izbekov, P. E.; Gordeev, E.; Titov, V. V.; Verstraeten, I. M.; Pinegina, T. K.; Tsadikovsky, E. I.; Heilweil, V. M.; Gingerich, S. B.

    2012-12-01

    During the US-Russia Geohazards Workshop held July 17-19, 2012 in Moscow, Russia the international research effort was asked to identify cooperative actions for disaster risk reduction, focusing on extreme geophysical events. As a part of this recommendation the PIRE project was developed to understand, quantify, forecast and protect the coastal zone aquifers and inland water resources of Kamchatka (Russia) and its ecosystems affected by the November 4, 1952 Kamchatka tsunami (Khalatyrka Beach near Petropavlovsk-Kamchatskiy) and the January 2, 1996 Karymskiy volcano eruption and the lake tsunami. This project brings together teams from U.S. universities and research institutions located in Russia. The research consortium was briefed on recent technical developments and will utilize samples secured via major international volcanic and tsunami programs for the purpose of advancing the study of submarine groundwater discharge (SGD) in the volcanic eruption and tsunami affected coastal areas and inland lakes of Kamchatka. We plan to accomplish this project by developing and applying the next generation of field sampling, remote sensing, laboratory techniques and mathematical tools to study groundwater-surface water interaction processes and SGD. We will develop a field and modeling approach to define SGD environment, key controls, and influence of volcano eruption and tsunami, which will provide a framework for making recommendations to combat contamination. This is valuable for politicians, water resource managers and decision-makers and for the volcano eruption and tsunami affected region water supply and water quality of Kamchatka. Data mining and results of our field work will be compiled for spatial modeling by Geo-Information System (GIS) using 3-D Earth Systems Visualization Lab. The field and model results will be communicated to interested stakeholders via an interactive web site. This will allow computation of SGD spatial patterns. In addition, thanks to the

  18. Optimization of the general acceptability though affective tests and response surface methodology of a dry cacao powder mixture based beverage

    Directory of Open Access Journals (Sweden)

    Elena Chau Loo Kung

    2013-09-01

    Full Text Available This research work had as main objective optimizing the general acceptability though affective tests and response surface methodology of a dry cacao powder mixture based beverage. We obtained formulations of mixtures of cacao powder with different concentrations of 15%, 17.5% and 20%, as well as lecithin concentrations of 0.1%; 0.3%; and 0.5% maintaining a constant content of sugar (25 %, Vanillin (1% that included cacao powder with different pH values: natural (pH 5 and alkalinized (pH 6.5 and pH 8 and water by difference to 100%, generating a total of fifteen treatments to be evaluated, according to the Box-Behnen design for three factors. The treatments underwent satisfaction level tests to establish the general acceptability. The treatment that included cacao powder with a concentration of 17.5 %, pH 6.5 and lecithin concentration of 0.3 % obtained the best levels of acceptability. The software Statgraphics Plus 5.1 was used to obtain the treatment with maximum acceptability that corresponded to cacao powder with pH 6.81, with a concentration of 18.24 % and soy lecithin in 0.28% with a tendency to what was obtained in the satisfaction levels tests. Finally we characterized in a physical-chemistry and microbiological way the optimum formulation as well as evaluated sensitively obtaining an acceptability of 6.17.

  19. Simulation of Canopy Leaf Inclination Angle in Rice

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-cui; LU Chuan-gen; HU Ning; YAO Ke-min; ZHANG Qi-jun; DAI Qi-gen

    2013-01-01

    A leaf inclination angle distribution model, which is applicable to simulate leaf inclination angle distribution in six heights of layered canopy at different growth stages, was established by component factors affecting plant type in rice. The accuracy of the simulation results was validated by measured values from a field experiment. The coefficient of determination (R2) and the root mean square error (RMSE) between the simulated and measured values were 0.9472 and 3.93%, respectively. The simulation results showed that the distribution of leaf inclination angles differed among the three plant types. The leaf inclination angles were larger in the compact variety Liangyoupeijiu with erect leaves than in the loose variety Shanyou 63 with droopy leaves and the intermediate variety Liangyou Y06. The leaf inclination angles were distributed in the lower range in Shanyou 63, which matched up with field measurements. The distribution of leaf inclination angles in the same variety changed throughout the seven growth stages. The leaf inclination angles enlarged gradually from transplanting to booting. During the post-booting period, the leaf inclination angle increased in Shanyou 63 and Liangyou Y06, but changed little in Liangyoupeijiu. At every growth stage of each variety, canopy leaf inclination angle distribution on the six heights of canopy layers was variable. As canopy height increased, the layered leaf area index (LAI) decreased in all the three plant types. However, while the leaf inclination angles showed little change in Liangyoupeijiu, they became larger in Shanyou 63 but smaller in Liangyou Y06. The simulation results used in the constructed model were very similar to the actual measurement values. The model provides a method for estimating canopy leaf inclination angle distribution in rice production.

  20. Estimation of leaf area with an integrating sphere.

    Science.gov (United States)

    Serrano, Lydia; Gamon, J. A.; Berry, J.

    1997-01-01

    Relative absorptance of intact branches measured with an integrating sphere was compared to leaf area estimated by conventional methods (volume displacement and scanning area meter) for three conifer species: Picea mariana (Mill.) BSP, Pinus banksiana (Lamb.) and Pseudotsuga menziesii (Mirb.) Franco. A consistent relationship between relative absorptance and surface area emerged for the three species. The ability to predict leaf area from absorptance was further explored by measuring branches of Pseudotsuga menziesii grown in varying light and nutrient regimes. When a single equation was used to predict leaf area under all growth conditions, errors were as large as 40% primarily because of variation in leaf absorptivity, with the largest errors associated with extremely nutrient-deficient foliage. When separate empirical equations were developed for each growth treatment, predicted leaf surface area agreed to within 5% of the area determined by the volume displacement method. Leaf surface area estimated from theoretical principles was also in good agreement with total surface area estimated independently by conventional methods. With proper accounting for needle absorptivity, which varied with growth conditions, leaf area estimates obtained by the integrating sphere method were of similar accuracy to those obtained by conventional methods, with the added advantage that the method allowed intact foliage to be sampled nondestructively in the field. Because the integrating sphere method preserves branch structure during measurement, it could provide a useful measure of needle area for photosynthetic or developmental studies requiring repeated sampling of the same branch.

  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. The ABCG transporter PEC1/ABCG32 is required for the formation of the developing leaf cuticle in Arabidopsis.

    Science.gov (United States)

    Fabre, Guillaume; Garroum, Imène; Mazurek, Sylwester; Daraspe, Jean; Mucciolo, Antonio; Sankar, Martial; Humbel, Bruno M; Nawrath, Christiane

    2016-01-01

    The cuticle is an essential diffusion barrier on aerial surfaces of land plants whose structural component is the polyester cutin. The PERMEABLE CUTICLE1/ABCG32 (PEC1) transporter is involved in plant cuticle formation in Arabidopsis. The gpat6 pec1 and gpat4 gapt8 pec1 double and triple mutants are characterized. Their PEC1-specific contributions to aliphatic cutin composition and cuticle formation during plant development are revealed by gas chromatography/mass spectrometry and Fourier-transform infrared spectroscopy. The composition of cutin changes during rosette leaf expansion in Arabidopsis. C16:0 monomers are in higher abundance in expanding than in fully expanded leaves. The atypical cutin monomer C18:2 dicarboxylic acid is more prominent in fully expanded leaves. Findings point to differences in the regulation of several pathways of cutin precursor synthesis. PEC1 plays an essential role during expansion of the rosette leaf cuticle. The reduction of C16 monomers in the pec1 mutant during leaf expansion is unlikely to cause permeability of the leaf cuticle because the gpat6 mutant with even fewer C16:0 monomers forms a functional rosette leaf cuticle at all stages of development. PEC1/ABCG32 transport activity affects cutin composition and cuticle structure in a specific and non-redundant fashion.

  3. Wind induced deformation and vibration of a Platanus acerifolia leaf

    Institute of Scientific and Technical Information of China (English)

    Chuan-Ping Shao; Ye-Jun Chen; Jian-Zhong Lin

    2012-01-01

    Deformation and vibration of twig-connected single leaf in wind is investigated experimentally.Results show that the Reynolds number based on wind speed and length of leaf blade is a key parameter to the aerodynamic problem.In case the front surface facing the wind and with an increase of Reynolds number,the leaf experiences static deformation,large amplitude and low frequency sway,reconfiguration to delta wing shape,flapping of tips,high frequency vibration of whole leaf blade,recovery of delta wing shape,and twig-leaf coupling vibration.Abrupt changes from one state to another occur at critical Reynolds numbers.In case the back surfacc facing the wind,the large amplitude and low frequency sway does not occur,the recovered delta wing shape is replaced by a conic shape,and the critical Reynolds numbers of vibrations are higher than the ones corresponding to the case with the front surface facing the wind.A pair of ram-horn vortex is observed behind the delta wing shaped leaf.A single vortex is found downstream of the conic shaped leaf.A lift is induced by the vortex,and this lift helps leaf to adjust position and posture,stabilize blade distortion and reduce drag and vibration.

  4. Developing multi-tracer approaches to constrain the parameterisation of leaf and soil CO2 and H2O exchange in land surface models

    Science.gov (United States)

    Ogée, Jerome; Wehr, Richard; Commane, Roisin; Launois, Thomas; Meredith, Laura; Munger, Bill; Nelson, David; Saleska, Scott; Zahniser, Mark; Wofsy, Steve; Wingate, Lisa

    2016-04-01

    The net flux of carbon dioxide between the land surface and the atmosphere is dominated by photosynthesis and soil respiration, two of the largest gross CO2 fluxes in the carbon cycle. More robust estimates of these gross fluxes could be obtained from the atmospheric budgets of other valuable tracers, such as carbonyl sulfide (COS) or the carbon and oxygen isotope compositions (δ13C and δ18O) of atmospheric CO2. Over the past decades, the global atmospheric flask network has measured the inter-annual and intra-annual variations in the concentrations of these tracers. However, knowledge gaps and a lack of high-resolution multi-tracer ecosystem-scale measurements have hindered the development of process-based models that can simulate the behaviour of each tracer in response to environmental drivers. We present novel datasets of net ecosystem COS, 13CO2 and CO18O exchange and vertical profile data collected over 3 consecutive growing seasons (2011-2013) at the Harvard forest flux site. We then used the process-based model MuSICA (multi-layer Simulator of the Interactions between vegetation Canopy and the Atmosphere) to include the transport, reaction, diffusion and production of each tracer within the forest and exchanged with the atmosphere. Model simulations over the three years captured well the impact of diurnally and seasonally varying environmental conditions on the net ecosystem exchange of each tracer. The model also captured well the dynamic vertical features of tracer behaviour within the canopy. This unique dataset and model sensitivity analysis highlights the benefit in the collection of multi-tracer high-resolution field datasets and the developement of multi-tracer land surface models to provide valuable constraints on photosynthesis and respiration across scales in the near future.

  5. THE SIZE AND SURFACE COATING OF NANOSILVER DIFFERENTIALLY AFFECTS BIOLOGICAL ACTIVITY IN BLOOD BRAIN BARRIER (RBEC4) CELLS.

    Science.gov (United States)

    Linking the physical properties of nanoparticles with differences in their biological activity is critical for understanding their potential toxicity and mode of action. The influence of aggregate size, surface coating, and surface charge on nanosilver's (nanoAg) movement through...

  6. Alkali treatment of microrough titanium surfaces affects macrophage/monocyte adhesion, platelet activation and architecture of blood clot formation

    Directory of Open Access Journals (Sweden)

    V Milleret

    2011-05-01

    Full Text Available Titanium implants are most commonly used for bone augmentation and replacement due to their favorable osseointegration properties. Here, hyperhydrophilic sand-blasted and acid-etched (SBA titanium surfaces were produced by alkali treatment and their responses to partially heparinized whole human blood were analyzed. Blood clot formation, platelet activation and activation of the complement system was analyzed revealing that exposure time between blood and the material surface is crucial as increasing exposure time results in higher amount of activated platelets, more blood clots formed and stronger complement activation. In contrast, the number of macrophages/monocytes found on alkali-treated surfaces was significantly reduced as compared to untreated SBA Ti surfaces. Interestingly, when comparing untreated to modified SBA Ti surfaces very different blood clots formed on their surfaces. On untreated Ti surfaces blood clots remain thin (below 15 mm, patchy and non-structured lacking large fibrin fiber networks whereas blood clots on differentiated surfaces assemble in an organized and layered architecture of more than 30 mm thickness. Close to the material surface most nucleated cells adhere, above large amounts of non-nucleated platelets remain entrapped within a dense fibrin fiber network providing a continuous cover of the entire surface. These findings might indicate that, combined with findings of previous in vivo studies demonstrating that alkali-treated SBA Ti surfaces perform better in terms of osseointegration, a continuous and structured layer of blood components on the blood-facing surface supports later tissue integration of an endosseous implant.

  7. Foraging on individual leaves by an intracellular feeding insect is not associated with leaf biomechanical properties or leaf orientation.

    Directory of Open Access Journals (Sweden)

    Justin Fiene

    Full Text Available Nearly all herbivorous arthropods make foraging-decisions on individual leaves, yet systematic investigations of the adaptive significance and ecological factors structuring these decisions are rare with most attention given to chewing herbivores. This study investigated why an intracellular feeding herbivore, Western flower thrips (WFT Frankliniella occidentalis Pergande, generally avoids feeding on the adaxial leaf surface of cotton cotyledons. WFT showed a significant aversion to adaxial-feeding even when excised-cotyledons were turned up-side (abaxial-side 'up', suggesting that negative-phototaxis was not a primary cause of thrips foraging patterns. No-choice bioassays in which individual WFT females were confined to either the abaxial or adaxial leaf surface showed that 35% fewer offspring were produced when only adaxial feeding was allowed, which coincided with 32% less plant feeding on that surface. To test the hypothesis that leaf biomechanical properties inhibited thrips feeding on the adaxial surface, we used a penetrometer to measure two variables related to the 'toughness' of each leaf surface. Neither variable negatively co-varied with feeding. Thus, while avoiding the upper leaf surface was an adaptive foraging strategy, the proximate cause remains to be elucidated, but is likely due, in part, to certain leaf properties that inhibit feeding.

  8. Wind-induced leaf transpiration

    Science.gov (United States)

    Huang, Cheng-Wei; Chu, Chia-Ren; Hsieh, Cheng-I.; Palmroth, Sari; Katul, Gabriel G.

    2015-12-01

    While the significance of leaf transpiration (fe) on carbon and water cycling is rarely disputed, conflicting evidence has been reported on how increasing mean wind speed (U) impacts fe from leaves. Here, conditions promoting enhancement or suppression of fe with increasing U for a wide range of environmental conditions are explored numerically using leaf-level gas exchange theories that combine a stomatal conductance model based on optimal water use strategies (maximizing the 'net' carbon gain at a given fe), energy balance considerations, and biochemical demand for CO2. The analysis showed monotonic increases in fe with increasing U at low light levels. However, a decline in modeled fe with increasing U were predicted at high light levels but only in certain instances. The dominant mechanism explaining this decline in modeled fe with increasing U is a shift from evaporative cooling to surface heating at high light levels. New and published sap flow measurements for potted Pachira macrocarpa and Messerschmidia argentea plants conducted in a wind tunnel across a wide range of U (2 - 8 m s-1) and two different soil moisture conditions were also employed to assess how fe varies with increasing U. The radiative forcing imposed in the wind tunnel was only restricted to the lower end of expected field conditions. At this low light regime, the findings from the wind tunnel experiments were consistent with the predicted trends.

  9. Leaf anatomy and photosynthesis

    NARCIS (Netherlands)

    Berghuijs, H.N.C.

    2016-01-01

    Keywords: CO2 diffusion, C3 photosynthesis, mesophyll conductance, mesophyll resistance, re-assimilation, photorespiration, respiration, tomato Herman Nicolaas Cornelis Berghuijs (2016). Leaf anatomy and photosynthesis; unravelling the CO2 diffusion pathway in C3 leaves. PhD thesis. Wageningen Unive

  10. Pharmacognostic evaluation of Cayratia trifolia (Linn.) leaf

    Institute of Scientific and Technical Information of China (English)

    Dinesh Kumar; Jyoti Gupta; Sunil Kumar; Renu Arya; Tarun Kumar; Ankit Gupta

    2012-01-01

    Objective: To present a detailed pharmacognostic study of the leaf of Cayratia trifolia (C. trifolia) Linn. (Vitaceae), an important plant in the Indian system of medicine. Methods: The macroscopy, microscopy, physiochemical analysis, preliminary testing, fluorescence analysis of powder of the plant and other WHO recommended methods for standardization were investigated. Results:Leaves are trifoliolated with petioles (2-3 cm) long. Leaflets are ovate to oblong-ovate, (2-8 cm) long, (1.5-5 cm) wide, pointed at the tip. The leaf surface shows the anisocytic type stomata covered with guard cells followed by epidermis layer. Leaf surface contents including veins, vein islet and vein termination were also determined. Transverse section of leaf shows the epidermis layer followed by cuticle layer and vascular bandles (xylem and phloem). The mesophyll is differentiated into palisade and spongy parenchyma. Abundant covering trichomes emerge from the upper epidermis. Trichomes are uniseriate and multicellular. Strips of collenchyma are present below and upper layer of epidermis. Conclusions: It can be concluded that the pharmacognostic profile of the C. trifolia is helpful in developing standards for quality, purity and sample identification.

  11. Factors affecting the wettability of different surface materials with vegetable oil at high temperatures and its relation to cleanability

    Energy Technology Data Exchange (ETDEWEB)

    Ashokkumar, Saranya, E-mail: saras@food.dtu.dk [Accoat A/S, Munkegardsvej 16, 3490 Kvistgard (Denmark); Food Production Engineering, DTU FOOD, Technical University of Denmark, 2800 Kgs. Lyngby (Denmark); Adler-Nissen, Jens [Food Production Engineering, DTU FOOD, Technical University of Denmark, 2800 Kgs. Lyngby (Denmark); Moller, Per [Department of Materials Science and Engineering, DTU Mechanical Engineering, Technical University of Denmark, 2800 Kgs. Lyngby (Denmark)

    2012-12-15

    Graphical abstract: Plot of cos {theta} versus temperature for metal and ceramic surfaces where cos {theta} rises linearly with increase in temperature. Highlights: Black-Right-Pointing-Pointer cos {theta} of olive oil on different surface materials rises linearly with increase in temperature. Black-Right-Pointing-Pointer Slopes are much higher for quasicrystalline and polymers than for ceramics. Black-Right-Pointing-Pointer Increase in surface roughness and surface flaws increases surface wettability. Black-Right-Pointing-Pointer Contact angle values gave information for grouping easy-clean polymers from other materials. Black-Right-Pointing-Pointer Contact angle measurements cannot directly estimate the cleanability of a surface. - Abstract: The main aim of the work was to investigate the wettability of different surface materials with vegetable oil (olive oil) over the temperature range of 25-200 Degree-Sign C to understand the differences in cleanability of different surfaces exposed to high temperatures in food processes. The different surface materials investigated include stainless steel (reference), PTFE (polytetrafluoroethylene), silicone, quasicrystalline (Al, Fe, Cr) and ceramic coatings: zirconium oxide (ZrO{sub 2}), zirconium nitride (ZrN) and titanium aluminum nitride (TiAlN). The ceramic coatings were deposited on stainless steel with two different levels of roughness. The cosine of the contact angle of olive oil on different surface materials rises linearly with increasing temperature. Among the materials analyzed, polymers (PTFE, silicone) gave the lowest cos {theta} values. Studies of the effect of roughness and surface flaws on wettability revealed that the cos {theta} values increases with increasing roughness and surface flaws. Correlation analysis indicates that the measured contact angle values gave useful information for grouping easy-clean polymer materials from the other materials; for the latter group, there is no direct relation between

  12. Optimisation of the extraction of olive (Olea europaea) leaf phenolics using water/ethanol-based solvent systems and response surface methodology.

    Science.gov (United States)

    Mylonaki, Stefania; Kiassos, Elias; Makris, Dimitris P; Kefalas, Panagiotis

    2008-11-01

    An experimental setup based on a 2(3) full-factorial, central-composite design was implemented with the aim of optimising the recovery of polyphenols from olive leaves by employing reusable and nontoxic solutions composed of water/ethanol/citric acid as extracting media. The factors considered were (i) the pH of the medium, (ii) the extraction time and (iii) the ethanol concentration. The model obtained produced a satisfactory fit to the data with regard to total polyphenol extraction (R(2) = 0.91, p = 0.0139), but not for the antiradical activity of the extracts (R(2) = 0.67, p = 0.3734). The second-order polynomial equation obtained after analysing the experimental data indicated that ethanol concentration and time mostly affected the extraction yield, but that increased pH values were unfavourable in this regard. The maximum theoretical yield was calculated to be 250.2 +/- 76.8 mg gallic acid equivalent per g of dry, chlorophyll-free tissue under optimal conditions (60% EtOH, pH 2 and 5 h). Liquid chromatography-electrospray ionisation mass spectrometry of the optimally obtained extract revealed that the principal phytochemicals recovered were luteolin 7-O-glucoside, apigenin 7-O-rutinoside and oleuropein, accompanied by smaller amounts of luteolin 3',7-O-diglucoside, quercetin 3-O-rutinoside (rutin), luteolin 7-O-rutinoside and luteolin 3'-O-glucoside. Simple linear regression analysis between the total polyphenol and antiradical activity values gave a low and statistically insignificant correlation (R(2) = 0.273, p > 0.05), suggesting that it is not the sheer amount of polyphenols that provides high antioxidant potency; instead, this potency is probably achieved through interactions among the various phenolic constituents.

  13. Model uncertainties affecting satellite-based inverse modeling of nitrogen oxides emissions and implications for surface ozone simulation

    Directory of Open Access Journals (Sweden)

    J.-T. Lin

    2012-06-01

    Full Text Available Errors in chemical transport models (CTMs interpreting the relation between space-retrieved tropospheric column densities of nitrogen dioxide (NO2 and emissions of nitrogen oxides (NOx have important consequences on the inverse modeling. They are however difficult to quantify due to lack of adequate in situ measurements, particularly over China and other developing countries. This study proposes an alternate approach for model evaluation over East China, by analyzing the sensitivity of modeled NO2 columns to errors in meteorological and chemical parameters/processes important to the nitrogen abundance. As a demonstration, it evaluates the nested version of GEOS-Chem driven by the GEOS-5 meteorology and the INTEX-B anthropogenic emissions and used with retrievals from the Ozone Monitoring Instrument (OMI to constrain emissions of NOx. The CTM has been used extensively for such applications. Errors are examined for a comprehensive set of meteorological and chemical parameters using measurements and/or uncertainty analysis based on current knowledge. Results are exploited then for sensitivity simulations perturbing the respective parameters, as the basis of the following post-model linearized and localized first-order modification. It is found that the model meteorology likely contains errors of various magnitudes in cloud optical depth, air temperature, water vapor, boundary layer height and many other parameters. Model errors also exist in gaseous and heterogeneous reactions, aerosol optical properties and emissions of non-nitrogen species affecting the nitrogen chemistry. Modifications accounting for quantified errors in 10 selected parameters increase the NO2 columns in most areas with an average positive impact of 22% in July and 10% in January. This suggests a possible systematic model bias such that the top-down emissions will be overestimated by the same magnitudes if the model is used

  14. Connecting the dots III: Night side cooling and surface friction affect climates of tidally locked terrestrial planets

    CERN Document Server

    Carone, L; Decin, L

    2016-01-01

    We investigate how night side cooling and surface friction impact surface temperatures and large scale circulation for tidally locked Earth-like planets. For each scenario, we vary the orbital period between $P_{rot}=1-100$~days and capture changes in climate states. We find drastic changes in climate states for different surface friction scenarios. For very efficient surface friction ($t_{s,fric}=$ 0.1 days), the simulations for short rotation periods ($P_{rot} \\leq$ 10 days) show predominantly standing extra tropical Rossby waves. These waves lead to climate states with two high latitude westerly jets and unperturbed meridional direct circulation. In most other scenarios, simulations with short rotation periods exhibit instead dominance by standing tropical Rossby waves. Such climate states have a single equatorial westerly jet, which disrupts direct circulation. Experiments with weak surface friction ($t_{s,fric}=~10 -100$ days) show decoupling between surface temperatures and circulation, which leads to s...

  15. Effects of nitrogen application rate and leaf age on the distribution pattern of leaf SPAD readings in the rice canopy.

    Directory of Open Access Journals (Sweden)

    Hu Yang

    Full Text Available A Soil-Plant Analysis Development (SPAD chlorophyll meter can be used as a simple tool for evaluating N concentration of the leaf and investigating the combined effects of nitrogen rate and leaf age on N distribution. We conducted experiments in a paddy field over two consecutive years (2008-2009 using rice plants treated with six different N application levels. N distribution pattern was determined by SPAD readings based on the temporal dynamics of N concentrations in individual leaves. At 62 days after transplantation (DAT in 2008 and DAT 60 in 2009, leaf SPAD readings increased from the upper to lower in the rice canopy that received N levels of 150 to 375 kg ha(-1The differences in SPAD readings between the upper and lower leaf were larger under higher N application rates. However, as plants grew, this atypical distribution of SPAD readings in canopy leaf quickly reversed to the general order. In addition, temporal dynamics of the leaf SPAD readings (N concentrations were fitted to a piecewise function. In our model, changes in leaf SPAD readings were divided into three stages: growth, functioning, and senescence periods. The leaf growth period lasted approximately 6 days, and cumulative growing days were not affected by N application rates. The leaf functioning period was represented with a relatively stable SPAD reading related to N application rate, and cumulative growing days were extended with increasing N application rates. A quadratic equation was utilized to describe the relationship between SPAD readings and leaf age during the leaf senescence period. The rate of decrease in SPAD readings increased with the age of leaves, but the rate was slowed by N application. As leaves in the lower canopy were physiologically older than leaves in the upper canopy, the rate of decrease in SPAD readings was faster in the lower leaves.

  16. Scaling relationships among twig size, leaf size and leafing intensity in a successional series of subtropical forests.

    Science.gov (United States)

    Yan, En-Rong; Wang, Xi-Hua; Chang, Scott X; He, Fangliang

    2013-06-01

    Scaling relationships among twig size, leaf size and leafing intensity fundamentally influence the twig-leaf deployment pattern, a property that affects the architecture and functioning of plants. However, our understanding of how these relationships change within a species or between species as a function of forest succession is unclear. We determined log-log scaling relationships between twig cross-sectional area (twig size) and each of total and individual leaf area, and leafing intensity (the number of leaves per twig volume) for 78 woody species along a successional series in subtropical evergreen forests in eastern China. The series included four stages: secondary shrub (S1), young (S2), sub-climax (S3) and climax evergreen broadleaved forests (S4). The scaling slopes in each of the three relationships did not differ among the four stages. The y-intercept did not shift among the successional stages in the relationship between twig cross-sectional area and total leaf area; however, the y-intercept was greatest in S4, intermediate in S3 and lowest in S2 and S1 for the relationship between twig size and individual leaf area, while the opposite pattern was found for the twig size-leafing intensity relationship. This indicates that late successional trees have few but large leaves while early successional trees have more small leaves per unit twig size. For the relationship between twig cross-sectional area and total leaf area, there was no difference in the regression slope between recurrent (appear in more than one stages) and non-recurrent species (appear in only one stage) for each of the S1-S2, S2-S3 and S3-S4 pairs. A significant difference in the y-intercept was found in the S2-S3 pair only. In the relationship between twig cross-sectional area and individual leaf area, the regression slope between recurrent and non-recurrent species was homogeneous in the S1-S2 and S3-S4 pairs, but heterogeneous in the S2-S3 pair. We conclude that forest succession caused

  17. Volatile Organic Compound (VOC) emissions from feedlot pen surface materials as affected by within pen location, moisture, and temperature

    Science.gov (United States)

    A laboratory study was conducted to evaluate the effects of pen location, moisture, and temperature on emissions of volatile organic compounds (VOC) from surface materials obtained from feedlot pens where beef cattle were fed a diet containing 30% wet distillers grain plus solubles. Surface material...

  18. Intraspecific growth and functional leaf trait responses to natural soil resource gradients for conifer species with contrasting leaf habit.

    Science.gov (United States)

    Walters, Michael B; Gerlach, John P

    2013-03-01

    Interspecific relationships among species mean leaf traits, performance and species resource/climate distributions help provide the foundation for a predictive, functionally based plant ecology. Intraspecific responses of leaf traits and performance to resource gradients and how these vary among species may be equally important but have received less attention. Here, we examine relationships between proxies of soil resource availability, leaf traits and growth (height at 25 years, SI25) for winter deciduous Larix decidua Mill. and evergreen Pinus resinosa Ait. trees distributed over soil resource gradients in the Great Lakes region of North America. We predicted that (i) leaf trait responses to soil resources within species will be similar to reported distributions of mean leaf traits over soil resource gradients among species; (ii) soil resource-related variation in leaf traits can help explain SI25; and (iii) SI25 will be greater for Larix than Pinus at higher soil resources and greater for Pinus than Larix at lower soil resources and this pattern will be associated with species differences in leaf trait responses to soil resources. Among the measured leaf traits (live N, Mg, Ca, K, P, and Mn, litter N, N resorption, carbon isotope discrimination, specific leaf area, lifespan), soil resources only impacted live and litter N for both species and K for Pinus. In turn, only the leaf traits responsive to soil resources affected SI25 in the expected manner. Larix had greater SI25 than Pinus across soil resource gradients and both species had similar growth and leaf trait sensitivities to resources. In summary: (i) several leaf traits reported to be associated with performance and edaphic distributions across species were, within species, unresponsive to nitrogen and water availability and unrelated to growth; (ii) leaf N showed high plasticity to soil resources and this plasticity was functionally relevant to growth over its entire range of response; (iii) large

  19. Fire in Australian Savannas: from leaf to landscape

    Science.gov (United States)

    Beringer, J.; Hutley, L. B.; Tapper, N. J.; Cernusak, L. A.; Lynch, A. H.; Görgen, K.; Abramson, D.; Uotila, P.

    2009-04-01

    Tropical savanna ecosystems account for 11.5% of the global landscape (Scholes and Hall 1996). Up to 75% of this landscape burns annually (Hao et al. 1990) and 50% of all biomass burning in tropical regions originates from savannas (Hao and Liu 1994). The wet-dry tropics of northern Australia feature extensive tracts of savanna vegetation which occupy approximately 2 million km2. This area is equivalent to 12% of the world's tropical savanna estate, making this savanna biome of global significance. Fire is arguably the greatest natural and anthropogenic environmental disturbance in this region. Vast tracts are burnt each year by pastoralists, aboriginal landholders and conservation managers (Russell-Smith et al. 2000; Williams et al. 2002). Fire in Australian savannas, results in a scorched canopy that dramatically reduces the green Leaf Area Index (LAI) and blackens the soil. These surface changes are likely to result in altered energy partitioning (enhanced sensible heat flux) and shifts in albedo. In addition, the aerodynamic and biological properties of the ecosystem may change, affecting surface-atmosphere coupling. For example, a loss of canopy leaf area due to fire could reduce canopy photosynthesis and evapotranspiration, greatly influencing post-fire fluxes of water and carbon. We measured radiative, energy and carbon exchanges over unburned and burned open forest savanna at Howard Springs, Darwin, Australia. Fire affected the radiative balance immediately following fire through the consumption of the grass-dominated understorey and blackening of the surface. Albedo was halved following fire (0.12 to 0.06). A moderate intensity fire resulted in a comprehensive canopy scorch and almost complete leaf drop in the weeks following fire. The shutdown of most leaves within the canopy reduced transpiration and altered energy partitioning. Leaf death and shedding also resulted in a cessation of ecosystem carbon uptake and the savanna turned from a sink to a source

  20. 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.

  1. 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.

  2. Elevated CO{sub 2} and leaf shape: Are dandelions getting toothier?

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, S.C.; Bazzaz, F.A. [Harvard Univ., Cambridge, MA (United States)

    1996-01-01

    Heteroblastic leaf development in Taraxacum officinale is compared between plants grown under ambient (350 ppm) vs. elevated (700 ppm) CO{sub 2} levels. Leaves of elevated CO{sub 2} plants exhibited more deeply incised leaf margins and relatively more slender leaf laminae than leaves of ambient CO{sub 2} plants. These differences were found to be significant in allometric analyses that controlled for differences in leaf size, as well as analyses that controlled for leaf development order. The effects of elevated CO{sub 2} on leaf shape were most pronounced when plants were grown individually, but detectable differences were also found in plants grown at high density. Although less dramatic than in Taraxacum, significant effects of elevated CO{sub 2} on leaf shape were also found in two other weedy rosette species, Plantago major and Rumex crispus. These observations support the long-standing hypothesis that leaf carbohydrate level plays an important role in regulating heteroblastic leaf development, though elevated CO{sub 2} may also affect leaf development through direct hormonal interactions or increased leaf water potential. In Taraxacum, pronounced modifications of leaf shape were found at CO{sub 2} levels predicted to occur within the next century. 33 refs., 5 figs.

  3. The effect of MTAD, an endodontic irrigant, on fibroblast attachment to periodontally affected root surfaces: A SEM analysis

    Directory of Open Access Journals (Sweden)

    Mostafa Ghandi

    2013-01-01

    Full Text Available Background: Root surface debridement (RSD is necessary to create an environment suitable for reattachment of the periodontium. Root surface conditioning may aid the formation of a biocompatible surface suitable for cell reattachment. BioPure™ MTAD (mixture of Doxycycline, citric acid and a detergent is an endodontic irrigant with antibacterial properties and the ability to remove smear layer. It was hypothesized that MTAD may be useful for root surface conditioning. The efficacy of MTAD as a conditioner was measured by examining fibroblast attachment to root surfaces. Materials and Methods: Thirty-two specimens of human teeth with advanced periodontal disease were used. The surfaces were root planed until smooth. Half of the specimens were treated with 0.9% saline and the other samples with Biopure MTAD. As a negative control group, five further samples were left unscaled with surface calculus. Human gingival fibroblast cells HGF1-PI1 were cultured and poured over the tooth specimens and incubated. After fixation, the samples were sputter-coated with gold and examined with a SEM. The morphology and number of attached, fixed viable cells were examined. The data was analysed using the Mann-Whitney-U statistical test. Results: There was no significant difference between the numbers of attached cells in the experimental group treated with MTAD and the control group treated with saline. Little or no attached cells were seen in the negative control group. Conclusion: RSD created an environment suitable for cell growth and attachment in a laboratory setting. The use of MTAD did not promote the attachment and growth of cells on the surface of human roots following RSD.

  4. Overexpressing sperm surface beta 1,4-galactosyltransferase in transgenic mice affects multiple aspects of sperm-egg interactions

    OpenAIRE

    1994-01-01

    Sperm surface beta 1,4-galactosyltransferase (GalTase) mediates fertilization in mice by binding to specific O-linked oligosaccharide ligands on the egg coat glycoprotein ZP3. Before binding the egg, sperm GalTase is masked by epididymally derived glycosides that are shed from the sperm surface during capacitation. After binding the egg, sperm- bound oligosaccharides on ZP3 induce the acrosome reaction by receptor aggregation, presumably involving GalTase. In this study, we asked how increasi...

  5. Wettability, polarity, and water absorption of holm oak leaves: effect of leaf side and age.

    Science.gov (United States)

    Fernández, Victoria; Sancho-Knapik, Domingo; Guzmán, Paula; Peguero-Pina, José Javier; Gil, Luis; Karabourniotis, George; Khayet, Mohamed; Fasseas, Costas; Heredia-Guerrero, José Alejandro; Heredia, Antonio; Gil-Pelegrín, Eustaquio

    2014-09-01

    Plant trichomes play important protective functions and may have a major influence on leaf surface wettability. With the aim of gaining insight into trichome structure, composition, and function in relation to water-plant surface interactions, we analyzed the adaxial and abaxial leaf surface of holm oak (Quercus ilex) as a model. By measuring the leaf water potential 24 h after the deposition of water drops onto abaxial and adaxial surfaces, evidence for water penetration through the upper leaf side was gained in young and mature leaves. The structure and chemical composition of the abaxial (always present) and adaxial (occurring only in young leaves) trichomes were analyzed by various microscopic and analytical procedures. The adaxial surfaces were wettable and had a high degree of water drop adhesion in contrast to the highly unwettable and water-repellent abaxial holm oak leaf sides. The surface free energy and solubility parameter decreased with leaf age, with higher values determined for the adaxial sides. All holm oak leaf trichomes were covered with a cuticle. The abaxial trichomes were composed of 8% soluble waxes, 49% cutin, and 43% polysaccharides. For the adaxial side, it is concluded that trichomes and the scars after trichome shedding contribute to water uptake, while the abaxial leaf side is highly hydrophobic due to its high degree of pubescence and different trichome structure, composition, and density. Results are interpreted in terms of water-plant surface interactions, plant surface physical chemistry, and plant ecophysiology.

  6. Interspecific variation of photosynthesis and leaf characteristics in canopy trees of five species of Dipterocarpaceae in a tropical rain forest.

    Science.gov (United States)

    Kenzo, Tanaka; Ichie, Tomoaki; Yoneda, Reiji; Kitahashi, Yoshinori; Watanabe, Yoko; Ninomiya, Ikuo; Koike, Takayoshi

    2004-10-01

    Photosynthetic rate, nitrogen concentration and morphological properties of canopy leaves were studied in 18 trees, comprising five dipterocarp species, in a tropical rain forest in Sarawak, Malaysia. Photosynthetic rate at light saturation (Pmax) differed significantly across species, varying from 7 to 18 micro mol m(-2) s(-1). Leaf nitrogen concentration and morphological properties, such as leaf blade and palisade layer thickness, leaf mass per area (LMA) and surface area of mesophyll cells per unit leaf area (Ames/A), also varied significantly across species. Among the relationships with leaf characteristics, Pmax had the strongest correlation with leaf mesophyll parameters, such as palisade cell layer thickness (r2 = 0.76, P palisade layer, with up to five or more layers. We conclude that interspecific variation in photosynthetic capacity in tropical rain forest canopies is influenced more by leaf mesophyll structure than by leaf thickness, LMA or leaf nitrogen concentration.

  7. TALE and Shape: How to Make a Leaf Different.

    Science.gov (United States)

    Di Giacomo, Elisabetta; Iannelli, Maria Adelaide; Frugis, Giovanna

    2013-05-06

    The Three Amino acid Loop Extension (TALE) proteins constitute an ancestral superclass of homeodomain transcription factors conserved in animals, plants and fungi. In plants they comprise two classes, KNOTTED1-LIKE homeobox (KNOX) and BEL1-like homeobox (BLH or BELL, hereafter referred to as BLH), which are involved in shoot apical meristem (SAM) function, as well as in the determination and morphological development of leaves, stems and inflorescences. Selective protein-protein interactions between KNOXs and BLHs affect heterodimer subcellular localization and target affinity. KNOXs exert their roles by maintaining a proper balance between undifferentiated and differentiated cell state through the modulation of multiple hormonal pathways. A pivotal function of KNOX in evolutionary diversification of leaf morphology has been assessed. In the SAM of both simple- and compound-leafed seed species, downregulation of most class 1 KNOX (KNOX1) genes marks the sites of leaf primordia initiation. However, KNOX1 expression is re-established during leaf primordia development of compound-leafed species to maintain transient indeterminacy and morphogenetic activity at the leaf margins. Despite the increasing knowledge available about KNOX1 protein function in plant development, a comprehensive view on their downstream effectors remains elusive. This review highlights the role of TALE proteins in leaf initiation and morphological plasticity with a focus on recent advances in the identification of downstream target genes and pathways.

  8. Efeitos da adubação NPK nos teores de macronutrientes das folhas de cana-de-açúcar (cana-soca Leaf macronutrient affected by NPK fertilization in sugar cane ratoon crops

    Directory of Open Access Journals (Sweden)

    Ademar Espironelo

    1986-01-01

    Full Text Available Foram utilizados oito ensaios de adubação NPK, em cana-soca do cultivar CB41-76, conduzidos em diversos solos do Estado de São Paulo, sendo quatro em Latossolo Roxo, um em Latossolo Vermelho-Amarelo textura argilosa, um em Latossolo Vermelho-Amarelo textura média, um em solos Podzolizados de Lins e Marília variação Manilha e outro em variação Lins. Aos quatro meses de idade da cana-soca, amostras de folhas + 3 foram coletadas para fins de análise de macronutrientes. As variações dos teores de macronutrientes foram mais acentuadas entre localidades do que entre doses dos respectivos adubos. Correlações positivas e significativas foram obtidas somente entre os teores de potássio nas folhas e as produções de cana. Devido às variações acentuadas dos teores de macronutrientes nas folhas de cana-soca em relação a diferentes localidades, as seguintes faixas de teores de nutrientes poderão ser, provisoriamente, consideradas como adequadas: N - 1,53 a 2,22%; P-0,14 a 0,20%; K - 1,24 a 1,59%; Ca-0,38 a 0,71%; Mg - 0,11 a 0,20% e S-0,11 a 0,31%.Eight fertilizer experiments with sugarcane ratoon crops (CB41-76 variety were carried out at several soils in the State of São Paulo, Brazil. Four of them were established on the Dusky Red Latosol, one in the clayey textured Red Yellow Latosol, one in a medium textured Dark Red Latosol and two in the Podzolized soils from calcareous sandstones sediments. Four month old leaves of position +3 were collected and analyzed for macronutrients. Considering the wide variation among localities, the following ranges of leaf nutrient contents were tentatively taken as adequate for sugarcane ratoon crops: N - 1.53 to 2.22%; P - 0.14 to 0.20%; K - 1.24 to 1.59%; Ca - 0.38 to 0.71%; Mg - 0.11 to 0.20% and S - 0.11 to 0.31%.

  9. Surface integrity of GH4169 affected by cantilever finish grinding and the application in aero-engine blades

    Directory of Open Access Journals (Sweden)

    Li Xun

    2015-10-01

    Full Text Available GH4169 is the main material for aero-engine blades and integrated blisks. Because GH4169 has a poor milling performance, the profile precision and surface integrity of blades and integrated blisks are difficult to be met by utilizing the conventional milling process, which directly influence the global performance and reliability of aero-engines. Through grinding experiments on parameters and surface integrity optimization, the helical cantilever grinding process utilizing a 300# CBN RB wheel is presented and applied in finish machining of GH4169 blades. The profile errors of the blade surface are within ±0.01 mm, the roughness is less than 0.4 μm, the residual compressive stresses and the hardening rate are appropriate, there are no phenomena of burr and smearing with the grinding chips, and the leading/trailing edge can be smoothly connected with the suction/pressure surface. All the experimental results indicate that this grinding process is greatly suitable for the profile finish machining of GH4169 blades.

  10. Surface integrity of GH4169 affected by cantilever finish grinding and the application in aero-engine blades

    Institute of Scientific and Technical Information of China (English)

    Li Xun; Ma Shuang; Meng Fanjun

    2015-01-01

    GH4169 is the main material for aero-engine blades and integrated blisks. Because GH4169 has a poor milling performance, the profile precision and surface integrity of blades and integrated blisks are difficult to be met by utilizing the conventional milling process, which directly influence the global performance and reliability of aero-engines. Through grinding experiments on parameters and surface integrity optimization, the helical cantilever grinding process utilizing a 300# CBN RB wheel is presented and applied in finish machining of GH4169 blades. The profile errors of the blade surface are within ±0.01 mm, the roughness is less than 0.4 lm, the residual compressive stresses and the hardening rate are appropriate, there are no phenomena of burr and smearing with the grinding chips, and the leading/trailing edge can be smoothly connected with the suction/pressure surface. All the experimental results indicate that this grinding process is greatly suitable for the profile finish machining of GH4169 blades.

  11. Adhesion of thrombotic components to the surface of a clinically used oxygenator is not affected by Trillium coating

    NARCIS (Netherlands)

    van den Goor, J.M.; van Oeveren, W.; Rutten, P.M.; Tijssen, J.G.; Eijsman, L.

    2006-01-01

    The Trillium (R) coating is designed to minimize adsorption of protein and the attachment of cells and other particles. The present study was undertaken to investigate the effect of surface coating on the adhesion of thrombotic components (activated platelets, white blood cells and fibrin) to the su

  12. Comparing Leaf and Root Insertion

    Directory of Open Access Journals (Sweden)

    Jaco Geldenhuys

    2010-07-01

    Full Text Available We consider two ways of inserting a key into a binary search tree: leaf insertion which is the standard method, and root insertion which involves additional rotations. Although the respective cost of constructing leaf and root insertion binary search trees trees, in terms of comparisons, are the same in the average case, we show that in the worst case the construction of a root insertion binary search tree needs approximately 50% of the number of comparisons required by leaf insertion.

  13. 有机无机肥配施对烤烟叶面分泌物数量及烟叶产质的影响%Effects of Mixing Application with Organic fertilizer and Inorganic Fertilizer on Leaf Surface Secretion Quantity and Quality and Yield of Flue-cured Tobacco

    Institute of Scientific and Technical Information of China (English)

    李伟; 周清明; 杨铁钊; 胡宏坤; 陆中山

    2011-01-01

    [目的]探讨有机肥和无机肥配施对烤烟叶片腺毛密度、叶面分泌物数量及烟叶主要化学成分和经济性状的影响.[方法]在大田设置施用100%化肥、70%化肥+30%芝麻饼肥、30%化肥+70%芝麻饼肥、100%芝麻饼肥4种试验处理,研究有机无机肥配施对烤烟叶片腺毛密度和分泌物数量及烟叶产质的影响.[结果]除100%芝麻饼肥处理外,随着施用处理中芝麻饼肥比例的提高,烤烟叶片腺毛密度和叶面分泌物数量逐渐增大;烟叶中主要化学成分含量比例的协调性逐渐增强,烤后烟叶的单产、均价、产值及上中等烟比例逐渐增大.[结论]有机肥和无机肥配施有利于烤烟叶片表面分泌物的形成及烟叶产质的提高,其中30%化肥+70%饼肥配施综合表现最优.%[Objective] The study aimed to investigate the effects of mixing application with the organic fertilizer and inorganic fertilizer on the leaf glandular hair density, leaf surface secretion quantity, main chemistry component and economic character of the flue-cured tobacco. [Method] In the field test, 4 fertilization treatments of 100% chemical fertilizer, 70% chemical fertilizer + 30% sesame cake fertilizer, 30% chemical fertilizer +70% sesame cake fertilizer and 100% sesame cake fertilizer were set up to study the effects of mixing application with the organic fertilizer and inorganic fertilizer on the leaf glandular hair density, leaf surface secretion quantity, and the yield and quality of the flue-cured tobacco. [ Result] Except the treatment of 100% cake fertilizer, as the proportion of cake fertilizer to total fertilizer was enhanced, both the glandular hair density and the surface secretion quantity was increased gradually; the coordination for the proportion of the main chemistry component in the tobacco leaf was enhanced gradually and the single yield, average price and output value of tobacco leaf and the proportion of superior and

  14. RNAi-mediated knocking- down of rlpk2 gene retarded soybean leaf senescence

    Institute of Scientific and Technical Information of China (English)

    LI Xiaoping; MA Yuanyuan; LI Pengli; ZHANG Liwen; WANG Yong; ZHANG Ren; WANG Ningning

    2005-01-01

    Leaf senescence that occurs in the last stage of leaf development is a genetically programmed process. It is very significant to elucidate the molecular mechanisms that control the initiation and progression of leaf senescence and the way the senescence signal is transduced. In a previous study on artificially induced soybean leaf senescence, we cloned a novel gene designated rlpk2 (Genbank Accession No. AY687391) that encodes a leucine-rich repeat (LRR) receptor like protein kinase. The expression level of rlpk2 gene was shown to be strongly up-regulated during both the natural leaf senescence process in this report and the artificially induced primary-leaf-senescence process in our previous work. The RNA interference (RNAi)-mediated knocking-down of rlpk2 dramatically retarded both the natural and nutrient deficiency-induced leaf senescence in transgenic soybean. The transgenic leaves showed more cell-aggregated surface structure and higher content of chlorophyll.

  15. 7 CFR 29.2528 - Leaf.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.2528 Section 29.2528 Agriculture Regulations...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2528 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  16. 7 CFR 29.3033 - Leaf.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.3033 Section 29.3033 Agriculture Regulations... Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  17. 7 CFR 29.3525 - Leaf.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.3525 Section 29.3525 Agriculture Regulations... Type 95) § 29.3525 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  18. Leaf growth of contrasting Poa species

    NARCIS (Netherlands)

    Fiorani, Fabio

    2002-01-01

    In the grass genus Poa a wide variation in final leaf size and leaf growth rate exists. In this thesis leaf growth was analyzed at different levels. At the cellular level, inherent variation in leaf elongation rate and final leaf size was correlated to the length of the elongation zone and to merist

  19. 7 CFR 29.1028 - Leaf.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.1028 Section 29.1028 Agriculture Regulations... Type 92) § 29.1028 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  20. Multiple autoclave cycles affect the surface of rotary nickel-titanium files: an atomic force microscopy study.

    Science.gov (United States)

    Valois, Caroline R A; Silva, Luciano P; Azevedo, Ricardo B

    2008-07-01

    The purpose of this study was to evaluate the surface of rotary nickel-titanium (Ni-Ti) files after multiple autoclave cycles. Two different types of rotary Ni-Ti (Greater Taper and ProFile) were attached to a glass base. After 1, 5, and 10 autoclave cycles the files were positioned in the atomic force microscope. The analyses were performed on 15 different points. The same files were used as control before any autoclave cycle. The following vertical topographic parameters were measured: arithmetic mean roughness, maximum height, and root mean square. The differences were tested by analysis of variance with Tukey test. All topographic parameters were higher for both Greater Taper and ProFile after 10 cycles compared with the control (P autoclave cycles increase the depth of surface irregularities located on rotary Ni-Ti files.

  1. Potential Environmental Factors Affecting Oil-Degrading Bacterial Populations in Deep and Surface Waters of the Northern Gulf of Mexico

    Science.gov (United States)

    Liu, Jiqing; Bacosa, Hernando P.; Liu, Zhanfei

    2017-01-01

    Understanding bacterial community dynamics as a result of an oil spill is important for predicting the fate of oil released to the environment and developing bioremediation strategies in the Gulf of Mexico. In this study, we aimed to elucidate the roles of temperature, water chemistry (nutrients), and initial bacterial community in selecting oil degraders through a series of incubation experiments. Surface (2 m) and bottom (1537 m) waters, collected near the Deepwater Horizon site, were amended with 200 ppm light Louisiana sweet crude oil and bacterial inoculums from surface or bottom water, and incubated at 4 or 24°C for 50 days. Bacterial community and residual oil were analyzed by pyrosequencing and gas chromatography-mass spectrometry (GC-MS), respectively. The results showed that temperature played a key role in selecting oil-degrading bacteria. Incubation at 4°C favored the development of Cycloclasticus, Pseudoalteromonas, Sulfitobacter, and Reinekea, while 24°C incubations enhanced Oleibacter, Thalassobius, Phaeobacter, and Roseobacter. Water chemistry and the initial community also had potential roles in the development of hydrocarbon-degrading bacterial communities. Pseudoalteromonas, Oleibacter, and Winogradskyella developed well in the nutrient-enriched bottom water, while Reinekea and Thalassobius were favored by low-nutrient surface water. We revealed that the combination of 4°C, crude oil and bottom inoculum was a key factor for the growth of Cycloclasticus, while the combination of surface inoculum and bottom water chemistry was important for the growth of Pseudoalteromonas. Moreover, regardless of the source of inoculum, bottom water at 24°C was a favorable condition for Oleibacter. Redundancy analysis further showed that temperature and initial community explained 57 and 19% of the variation observed, while oil and water chemistry contributed 14 and 10%, respectively. Overall, this study revealed the relative roles of temperature, water

  2. Detoxification of Implant Surfaces Affected by Peri-Implant Disease: An Overview of Non-surgical Methods

    Science.gov (United States)

    Valderrama, Pilar; Blansett, Jonathan A; Gonzalez, Mayra G; Cantu, Myrna G; Wilson, Thomas G

    2014-01-01

    Objective: The aim of this review is to summarize the findings of studies that have evaluated non-surgical approaches for detoxification of implant body surfaces in vitro and in vivo, and to evaluate clinical trials on the use of these methodologies for treating peri-implant disease. Materials and methods: A literature search was conducted using MEDLINE (Pubmed) from 1966 to 2013. In vitro and in vivo studies as well as clinical trials on non-surgical therapy were evaluated. The outcome variables were the ability of the therapeutic method to eliminate the biofilm and endotoxins from the implant surface, the changes in clinical parameters including probing depth, clinical attachment levels, bleeding on probing; radiographic bone fill and histological re-osseointegration. Results: From 134 articles found 35 were analyzed. The findings, advantages and disadvantages of using lasers as well as mechanical and chemical methods are discussed. Most of the in vivo and human studies used combination therapies which makes determining the efficacy of one specific method difficult. Most human studies are case series with short term longitudinal analysis without survival or failure reports. Conclusion: Complete elimination of the biofilms is difficult to achieve using these approaches. All therapies induce changes of the chemical and physical properties of the implant surface. Re-osseointegration may be difficult to achieve if not impossible without surgical access to ensure thorough debridement of the defect and detoxification of the implant surface. Combination protocols for non-surgical treatment of peri-implantitis in humans have shown some positive clinical results but long-term evaluation to evaluate the validity and reliability of the techniques is needed. PMID:24894571

  3. Optimal leaf positions for chlorophyll meter measurement in rice

    Directory of Open Access Journals (Sweden)

    Zhaofeng eYuan

    2016-05-01

    Full Text Available The Soil Plant Analysis Development (SPAD chlorophyll meter is one of the most commonly used diagnostic tools to measure crop nitrogen status. However, the measurement method of the meter could significantly affect the accuracy of the final estimation. Thus, this research was undertaken to develop a new methodology to optimize SPAD meter measurements in rice (Oryza sativa L.. A flatbed color scanner was used to map the dynamic chlorophyll distribution and irregular leaf shapes. Calculus algorithm was adopted to estimate the potential positions for SPAD meter measurement along the leaf blade. Data generated by the flatbed color scanner and SPAD meter were analysed simultaneously. The results suggested that a position 2/3 of the distance from the leaf base to the apex (2/3 position could represent the chlorophyll content of the entire leaf blade, as indicated by the relatively low variance of measurements at that positon. SPAD values based on di-positional leaves and the extracted chlorophyll a and b contents were compared. This comparison showed that the 2/3 position on the lower leaves tended to be more sensitive to changes in chlorophyll content. Finally, the 2/3 position and average SPAD values of the fourth fully expanded leaf from the top were compared with leaf nitrogen concentration. The results showed the 2/3 position on that leaf was most suitable for predicting the nitrogen status of rice. Based on these results, we recommend making SPAD measurements at the 2/3 position on the fourth fully expanded leaf from the top. The coupling of dynamic chlorophyll distribution and irregular leaf shapes information can provide a promising approach for the calibration of SPAD meter measurement, which can further benefit the in situ nitrogen management by providing reliable estimation of crops nitrogen nutrition status.

  4. Plasticity in sunflower leaf and cell growth under high salinity.

    Science.gov (United States)

    Céccoli, G; Bustos, D; Ortega, L I; Senn, M E; Vegetti, A; Taleisnik, E

    2015-01-01

    A group of sunflower lines that exhibit a range of leaf Na(+) concentrations under high salinity was used to explore whether the responses to the osmotic and ionic components of salinity can be distinguished in leaf expansion kinetics analysis. It was expected that at the initial stages of the salt treatment, leaf expansion kinetics changes would be dominated by responses to the osmotic component of salinity, and that later on, ion inclusion would impose further kinetics changes. It was also expected that differential leaf Na(+) accumulation would be reflected in specific changes in cell division and expansion rates. Plants of four sunflower lines were gradually treated with a relatively high (130 mm NaCl) salt treatment. Leaf expansion kinetics curves were compared in leaves that were formed before, during and after the initiation of the salt treatment. Leaf areas were smaller in salt-treated plants, but the analysis of growth curves did not reveal differences that could be attributed to differential Na(+) accumulation, since similar changes in leaf expansion kinetics were observed in lines with different magnitudes of salt accumulation. Nevertheless, in a high leaf Na(+) -including line, cell divisions were affected earlier, resulting in leaves with proportionally fewer cells than in a Na(+) -excluding line. A distinct change in leaf epidermal pavement shape caused by salinity is reported for the first time. Mature pavement cells in leaves of control plants exhibited typical lobed, jigsaw-puzzle shape, whereas in treated plants, they tended to retain closer-to-circular shapes and a lower number of lobes.

  5. Anatomy of Begonia lucernae Wettst. (Begoniaceae leaf

    Directory of Open Access Journals (Sweden)

    Rodica BERCU

    2015-06-01

    Full Text Available The paper presents anatomical aspects concerning the leaf structure of Begonia lucernae Wettst. belonging to Begoniaceae family. Anatomically, the petiole has a unistratous epidermis and a differentiated mesophyll. The vascular system is fascicular type with a large number of collateral bundles placed into a basic tissue. The lamina is composed of an upper and a lower epidermis and hypodermis as well and the mesophyll. The mesophyll differentiated into palisade tissue and spongy tissue with the same vascular bundle structure such as those of the petiole but with foliar arrangement of the conductive tissues. Stomata are present to the lower epidermis. Paradermal section discloses stright walls epidermal cells and anisocytic stomata. It was calculated the number of stomata/mm2 of leaf surface and the stomatal index as well.

  6. (TECTONA GRANDIS LEAF POWDER

    Directory of Open Access Journals (Sweden)

    Yash Mishra

    2015-01-01

    Full Text Available In this study, the adsorption potential of Teak (Tectona grandis leaf powder (TLP toremove Methylene blue (MB and Malachite Green (MG dye molecules from aqueoussolution was investigated. Batch experiments were conducted to evaluate the influenceof operational parameters such as, pH (2−9, adsorbent dosage (1−7 g/L, contact time(15−150 minutes and initial dye concentration (20−120 mg/L at stirring speed of 150rpm for the adsorption of MB and MG on TLP. Maximum removal efficiency of 98.4%and 95.1% was achieved for MB and MG dye, respectively. The experimentalequilibrium data were analysed using Langmuir, Freundlich and Temkin isothermmodels and it was found that, it fitted well to the Freundlich isotherm model. Thesurface structure and morphology of the adsorbent was characterized using scanningelectron microscopy (SEM and the presence of functional groups and its interactionwith the dye molecules were analysed using Fourier transform infrared spectroscopy(FTIR. Based on the investigation, it has been demonstrated that the teak leaf powderhas good potential for effective adsorption of methylene blue and malachite green dye.

  7. Leaf Shape Responds to Temperature but Not CO2 in Acer rubrum

    OpenAIRE

    Royer, Dana L.

    2012-01-01

    The degree of leaf dissection and the presence of leaf teeth, along with tooth size and abundance, inversely correlate with mean annual temperature (MAT) across many plant communities. These relationships form the core of several methods for reconstructing MAT from fossils, yet the direct selection of temperature on tooth morphology has not been demonstrated experimentally. It is also not known if atmospheric CO(2) concentration affects leaf shape, limiting confidence in ancient climate recon...

  8. Fire ants protect mealybugs against their natural enemies by utilizing the leaf shelters constructed by the leaf roller Sylepta derogata.

    Science.gov (United States)

    Zhou, Aiming; Zeng, Ling; Lu, Yongyue; Xu, Yijuan; Liang, Guangwen

    2012-01-01

    The importance of mutualism is receiving more attention in community ecology. In this study, the fire ant Solenopsis invicta was found to take advantage of the shelters constructed by the leaf roller Sylepta derogata to protect mealybugs (Phenacoccus solenopsis) against their natural enemies. This protective effect of fire ant tending on the survival of mealybugs in shelters was observed when enemies and leaf rollers were simultaneously present. Specifically, fire ants moved the mealybugs inside the shelters produced by S. derogata on enemy-infested plants. Compared with that in plants without ants, the survival of mealybugs in shelters in the presence of natural enemies in plants with ants markedly improved. Both the protection of ants and the shelters provided by leaf rollers did not affect the survival of mealybugs in the absence of enemies in plants. Ants and leaf rollers significantly improved the survival of mealybugs in predator-infested plants, whereas no such improvement was observed in parasitoid-infested ones.

  9. Energy absorption during impact on the proximal femur is affected by body mass index and flooring surface.

    Science.gov (United States)

    Bhan, Shivam; Levine, Iris C; Laing, Andrew C

    2014-07-18

    Impact mechanics theory suggests that peak loads should decrease with increase in system energy absorption. In light of the reduced hip fracture risk for persons with high body mass index (BMI) and for falls on soft surfaces, the purpose of this study was to characterize the effects of participant BMI, gender, and flooring surface on system energy absorption during lateral falls on the hip with human volunteers. Twenty university-aged participants completed the study with five men and five women in both low BMI (27.5 kg/m(2)) groups. Participants underwent lateral pelvis release experiments from a height of 5 cm onto two common floors and four safety floors mounted on a force plate. A motion-capture system measured pelvic deflection. The energy absorbed during the initial compressive phase of impact was calculated as the area under the force-deflection curve. System energy absorption was (on average) 3-fold greater for high compared to low BMI participants, but no effects of gender were observed. Even after normalizing for body mass, high BMI participants absorbed 1.8-fold more energy per unit mass. Additionally, three of four safety floors demonstrated significantly increased energy absorption compared to a baseline resilient-rolled-sheeting system (% increases ranging from 20.7 to 28.3). Peak system deflection was larger for high BMI persons and for impacts on several safety floors. This study indicates that energy absorption may be a common mechanism underlying the reduced risk of hip fracture for persons with high BMI and for those who fall on soft surfaces.

  10. Evaluation of leaf removal as a means to reduce nutrient concentrations and loads in urban stormwater.

    Science.gov (United States)

    Selbig, William R

    2016-11-15

    While the sources of nutrients to urban stormwater are many, the primary contributor is often organic detritus, especially in areas with dense overhead tree canopy. One way to remove organic detritus before it becomes entrained in runoff is to implement a city-wide leaf collection and street cleaning program. Improving our knowledge of the potential reduction of nutrients to stormwater through removal of leaves and other organic detritus on streets could help tailor more targeted municipal leaf collection programs. This study characterized an upper ideal limit in reductions of total and dissolved forms of phosphorus and nitrogen in stormwater through implementation of a municipal leaf collection and street cleaning program in Madison, WI, USA. Additional measures were taken to remove leaf litter from street surfaces prior to precipitation events. Loads of total and dissolved phosphorus were reduced by 84 and 83% (premoval program. Without leaf removal, 56% of the annual total phosphorus yield (winter excluded) was due to leaf litter in the fall compared to 16% with leaf removal. Despite significant reductions in load, total nitrogen showed only minor changes in fall yields without and with leaf removal at 19 and 16%, respectively. The majority of nutrient concentrations were in the dissolved fraction making source control through leaf removal one of the few treatment options available to environmental managers when reducing the amount of dissolved nutrients in stormwater runoff. Subsequently, the efficiency, frequency, and timing of leaf removal and street cleaning are the primary factors to consider when developing a leaf management program.

  11. The Brugada syndrome mutation A39V does not affect surface expression of neuronal rat Cav1.2 channels

    Directory of Open Access Journals (Sweden)

    Simms Brett A

    2012-03-01

    Full Text Available Abstract Background A loss of function of the L-type calcium channel, Cav1.2, results in a cardiac specific disease known as Brugada syndrome. Although many Brugada syndrome channelopathies reduce channel function, one point mutation in the N-terminus of Cav1.2 (A39V has been shown to elicit disease a phenotype because of a loss of surface trafficking of the channel. This lack of cell membrane expression could not be rescued by the trafficking chaperone Cavβ. Findings We report that despite the striking loss of trafficking described previously in the cardiac Cav1.2 channel, the A39V mutation while in the background of the brain isoform traffics and functions normally. We detected no differences in biophysical properties between wild type Cav1.2 and A39V-Cav1.2 in the presence of either a cardiac (Cavβ2b, or a neuronal beta subunit (Cavβ1b. In addition, the A39V-Cav1.2 mutant showed a normal Cavβ2b mediated increase in surface expression in tsA-201 cells. Conclusions The Brugada syndrome mutation A39V when introduced into rat brain Cav1.2 does not trigger the loss-of-trafficking phenotype seen in a previous study on the human heart isoform of the channel.

  12. Mutations in Arabidopsis thaliana genes involved in the tryptophan biosynthesis pathway affect root waving on tilted agar surfaces

    Science.gov (United States)

    Rutherford, R.; Gallois, P.; Masson, P. H.

    1998-01-01

    Arabidopsis thaliana roots grow in a wavy pattern upon a slanted surface. A novel mutation in the anthranilate synthase alpha 1 (ASA1) gene, named trp5-2wvc1, and mutations in the tryptophan synthase alpha and beta 1 genes (trp3-1 and trp2-1, respectively) confer a compressed root wave phenotype on tilted agar surfaces. When trp5-2wvc1 seedlings are grown on media supplemented with anthranilate metabolites, their roots wave like wild type. Genetic and pharmacological experiments argue that the compressed root wave phenotypes of trp5-2wvc1, trp2-1 and trp3-1 seedlings are not due to reduced IAA biosynthetic potential, but rather to a deficiency in L-tryptophan (L-Trp), or in a L-Trp derivative. Although the roots of 7-day-old seedlings possess higher concentrations of free L-Trp than the shoot as a whole, trp5-2wvc1 mutants show no detectable alteration in L-Trp levels in either tissue type, suggesting that a very localized shortage of L-Trp, or of a L-Trp-derived compound, is responsible for the observed phenotype.

  13. The Chemical Composition of Surface Waters of Technogenically Affected Geo-Systems in the Eastern Donbas Region

    Directory of Open Access Journals (Sweden)

    Olga S. Reshetnyak

    2014-11-01

    Full Text Available Based on an analysis of literary data and the author’s own research findings, the paper assesses the factors in the formation of the chemical composition of surface and subterranean waters and the variability of the chemical composition and quality of river waters in the eastern Donbas region. The author illustrates that the major negative effect of the impact of technogenic waters on river waters is salinization. The paper points up a high level of pollution in river waters with a broad spectrum of metal compounds, among which the biggest threat comes from Fegen, Al, Mn, Cu, and Sr, which is of a steady nature. The quality of water in the majority of rivers in the eastern Donbas region is evaluated as Quality Class 4 – dirty and/or very dirty. The findings can be used in resolving a whole array of scientific and applied objectives related to assessing the migration of chemical substances and the level of pollution in surface and subterranean waters and forecasting the condition of water sites and the quality of water, as well as in carrying out water-protection activities in the region.

  14. A simplified GIS approach to modeling global leaf water isoscapes.

    Directory of Open Access Journals (Sweden)

    Jason B West

    Full Text Available The stable hydrogen (delta(2H and oxygen (delta(18O isotope ratios of organic and inorganic materials record biological and physical processes through the effects of substrate isotopic composition and fractionations that occur as reactions proceed. At large scales, these processes can exhibit spatial predictability because of the effects of coherent climatic patterns over the Earth's surface. Attempts to model spatial variation in the stable isotope ratios of water have been made for decades. Leaf water has a particular importance for some applications, including plant organic materials that record spatial and temporal climate variability and that may be a source of food for migrating animals. It is also an important source of the variability in the isotopic composition of atmospheric gases. Although efforts to model global-scale leaf water isotope ratio spatial variation have been made (especially of delta(18O, significant uncertainty remains in models and their execution across spatial domains. We introduce here a Geographic Information System (GIS approach to the generation of global, spatially-explicit isotope landscapes (= isoscapes of "climate normal" leaf water isotope ratios. We evaluate the approach and the resulting products by comparison with simulation model outputs and point measurements, where obtainable, over the Earth's surface. The isoscapes were generated using biophysical models of isotope fractionation and spatially continuous precipitation isotope and climate layers as input model drivers. Leaf water delta(18O isoscapes produced here generally agreed with latitudinal averages from GCM/biophysical model products, as well as mean values from point measurements. These results show global-scale spatial coherence in leaf water isotope ratios, similar to that observed for precipitation and validate the GIS approach to modeling leaf water isotopes. These results demonstrate that relatively simple models of leaf water enrichment

  15. CO2 leakage from carbon dioxide capture and storage (CCS) systems affects organic matter cycling in surface marine sediments.

    Science.gov (United States)

    Rastelli, Eugenio; Corinaldesi, Cinzia; Dell'Anno, Antonio; Amaro, Teresa; Greco, Silvestro; Lo Martire, Marco; Carugati, Laura; Queirós, Ana M; Widdicombe, Stephen; Danovaro, Roberto

    2016-12-01

    Carbon dioxide capture and storage (CCS), involving the injection of CO2 into the sub-seabed, is being promoted worldwide as a feasible option for reducing the anthropogenic CO2 emissions into the atmosphere. However, the effects on the marine ecosystems of potential CO2 leakages originating from these storage sites have only recently received scientific attention, and little information is available on the possible impacts of the resulting CO2-enriched seawater plumes on the surrounding benthic ecosystem. In the present study, we conducted a 20-weeks mesocosm experiment exposing coastal sediments to CO2-enriched seawater (at 5000 or 20,000 ppm), to test the effects on the microbial enzymatic activities responsible for the decomposition and turnover of the sedimentary organic matter in surface sediments down to 15 cm depth. Our results indicate that the exposure to high-CO2 concentrations reduced significantly the enzymatic activities in the top 5 cm of sediments, but had no effects on subsurface sediment horizons (from 5 to 15 cm depth). In the surface sediments, both 5000 and 20,000 ppm CO2 treatments determined a progressive decrease over time in the protein degradation (up to 80%). Conversely, the degradation rates of carbohydrates and organic phosphorous remained unaltered in the first 2 weeks, but decreased significantly (up to 50%) in the longer term when exposed at 20,000 ppm of CO2. Such effects were associated with a significant change in the composition of the biopolymeric carbon (due to the accumulation of proteins over time in sediments exposed to high-pCO2 treatments), and a significant decrease (∼20-50% at 5000 and 20,000 ppm respectively) in nitrogen regeneration. We conclude that in areas immediately surrounding an active and long-lasting leak of CO2 from CCS reservoirs, organic matter cycling would be significantly impacted in the surface sediment layers. The evidence of negligible impacts on the deeper sediments should be considered with

  16. Estimating environmental conditions affecting protozoal pathogen removal in surface water wetland systems using a multi-scale, model-based approach.

    Science.gov (United States)

    Daniels, Miles E; Hogan, Jennifer; Smith, Woutrina A; Oates, Stori C; Miller, Melissa A; Hardin, Dane; Shapiro, Karen; Los Huertos, Marc; Conrad, Patricia A; Dominik, Clare; Watson, Fred G R

    2014-09-15

    Cryptosporidium parvum, Giardia lamblia, and Toxoplasma gondii are waterborne protozoal pathogens distributed worldwide and empirical evidence suggests that wetlands reduce the concentrations of these pathogens under certain environmental conditions. The goal of this study was to evaluate how protozoal removal in surface water is affected by the water temperature, turbidity, salinity, and vegetation cover of wetlands in the Monterey Bay region of California. To examine how protozoal removal was affected by these environmental factors, we conducted observational experiments at three primary spatial scales: settling columns, recirculating wetland mesocosm tanks, and an experimental research wetland (Molera Wetland). Simultaneously, we developed a protozoal transport model for surface water to simulate the settling columns, the mesocosm tanks, and the Molera Wetland. With a high degree of uncertainty expected in the model predictions and field observations, we developed the model within a Bayesian statistical framework. We found protozoal removal increased when water flowed through vegetation, and with higher levels of turbidity, salinity, and temperature. Protozoal removal in surface water was maximized (~0.1 hour(-1)) when flowing through emergent vegetation at 2% cover, and with a vegetation contact time of ~30 minutes compared to the effects of temperature, salinity, and turbidity. Our studies revealed that an increase in vegetated wetland area, with water moving through vegetation, would likely improve regional water quality through the reduction of fecal protozoal pathogen loads.

  17. Dissolved organic matter dynamics in surface waters affected by oil spill pollution: Results from the Serious Game exercise

    Science.gov (United States)

    Gonnelli, M.; Galletti, Y.; Marchetti, E.; Mercadante, L.; Retelletti Brogi, S.; Ribotti, A.; Sorgente, R.; Vestri, S.; Santinelli, C.

    2016-11-01

    Dissolved organic carbon (DOC), chromophoric and fluorescent dissolved organic matter (CDOM and FDOM, respectively) surface distribution was studied during the Serious Game exercise carried out in the Eastern Ligurian Sea, where an oil spill was localized by using satellite images and models. This paper reports the first DOC, CDOM and FDOM data for this area together with an evaluation of fluorescence as a fast and inexpensive tool for early oil spill detection in marine waters. The samples collected in the oil spill showed a fluorescence intensity markedly higher ( 5 fold) than all the other samples. The excitation-emission matrixes, coupled with parallel factor analysis (PARAFAC), allowed for the identification in the FDOM pool of a mixture of polycyclic aromatic hydrocarbons, humic-like and protein-like fluorophores.

  18. Does river restoration affect diurnal and seasonal changes to surface water quality? A study along the Thur River, Switzerland

    Energy Technology Data Exchange (ETDEWEB)

    Chittoor Viswanathan, Vidhya [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Water Resources and Drinking Water, Überlandstrasse 133, 8600 Dübendorf (Switzerland); Université de Neuchâtel, Centre d' Hydrogéologie et de Géothermie (CHYN), Rue Emile-Argand 11, CH-2000 Neuchâtel (Switzerland); Molson, John [Université Laval, Département de Géologie et Génie Géologique, Québec City, Québec (Canada); Schirmer, Mario [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Water Resources and Drinking Water, Überlandstrasse 133, 8600 Dübendorf (Switzerland); Université de Neuchâtel, Centre d' Hydrogéologie et de Géothermie (CHYN), Rue Emile-Argand 11, CH-2000 Neuchâtel (Switzerland)

    2015-11-01

    Changes in river water quality were investigated along the lower reach of the Thur River, Switzerland, following river restoration and a summer storm event. River restoration and hydrological storm events can each cause dramatic changes to water quality by affecting various bio-geochemical processes in the river, but have to date not been well documented, especially in combination. Evaluating the success of river restoration is often restricted in large catchments due to a lack of high frequency water quality data, which are needed for process understanding. These challenges were addressed in this study by measuring water quality parameters including dissolved oxygen (DO), temperature, pH, electrical conductivity (EC), nitrate and dissolved organic carbon (DOC) with a high temporal frequency (15 min–1 h) over selected time scales. In addition, the stable isotopes of water (δD and δ{sup 18}O-H{sub 2}O) as well as those of nitrate (δ{sup 15}N-NO{sub 3}{sup −} and δ{sup 18}O-NO{sub 3}{sup −}) were measured to follow changes in water quality in response to the hydrological changes in the river. To compare the spatial distribution of pre- and post-restoration water quality, the sampling stations were chosen upstream and downstream of the restored section. The diurnal and seasonal changes were monitored by conducting 24-hour campaigns in three seasons (winter, summer and autumn) in 2012 and 2013. The amplitude of the diurnal changes of the various observed parameters showed significant seasonal and spatial variability. Biological processes — mainly photosynthesis and respiration — were found to be the major drivers of these diurnal cycles. During low flow in autumn, a reduction of nitrate (attributed to assimilation by autotrophs) in the pre-dawn period and a production of DOC during the daytime (attributed to photosynthesis) were observed downstream of the restored site. Further, a summer storm event was found to override the influence of these biological

  19. Numerical Investigation on Jet Impingement Behaviors Affected by a Vertically Rotating Disk Suspended Close to the Surface

    Directory of Open Access Journals (Sweden)

    Liu Bo

    2014-01-01

    Full Text Available A simplified physical model is built up to study the swirl flow effect induced by a rotating disk on the jet impingement behaviors, which is adopted to simulate the grinding process. To solve the definition problem of the interface between a rotating disk and a stationary plate in the computational simulation, a tiny gap is set between the rotating disk and the stationary plate. The results show that the rotating disk suspended above the surface adds more complexity to the flow field of jet impingement on a stationary plate. The swirling flow around the rotating disk obstructs the impinging jet flow to penetrate into the interfacial contact zone and forces the wall jet across the rotating disk to flow along transverse directions. For the given jet impinging velocity and nozzle orientation, as the disk rotational speed increases, the effect of the rotating disk on the impinging jet flow behaves more significantly. The impinging jet with small inject velocity is difficult to penetrate through the interfacial contact zone to follow by the disk swirl flows. For smaller jet impinging distance or larger oblique angle, the flow recirculation away from the interfacial contact zone becomes stronger.

  20. Iron oxide nanoparticles surface coating and cell uptake affect biocompatibility and inflammatory responses of endothelial cells and macrophages

    Science.gov (United States)

    Orlando, Antonina; Colombo, Miriam; Prosperi, Davide; Gregori, Maria; Panariti, Alice; Rivolta, Ilaria; Masserini, Massimo; Cazzaniga, Emanuela

    2015-09-01

    Engineered iron oxide nanoparticles (IONP) offer the possibility of a wide range of medical uses, from clinical imaging to magnetically based hyperthermia for tumor treatment. These applications require their systemic administration in vivo. An important property of nanoparticles is their stability in biological media. For this purpose, a multicomponent nanoconstruct combining high colloidal stability and improved physical properties was synthesized and characterized. IONP were coated with an amphiphilic polymer (PMA), which confers colloidal stability, and were pegylated in order to obtain the nanoconstruct PEG-IONP-PMA. The aim of this study was to utilize cultured human endothelial cells (HUVEC) and murine macrophages, taken as model of cells exposed to NP after systemic administration, to assess the biocompatibility of PEG-IONP-PMA (23.1 ± 1.4 nm) or IONP-PMA (15.6 ± 3.4 nm). PEG-IONP-PMA, tested at different concentrations as high as 20 μg mL-1, exhibited no cytotoxicity or inflammatory responses. By contrast, IONP-PMA showed a concentration-dependent increase of cytotoxicity and of TNF-α production by macrophages and NO production by HUVECs. Cell uptake analysis suggested that after PEGylation, IONP were less internalized either by macrophages or by HUVEC. These results suggest that the choice of the polymer and the chemistry of surface functionalization are a crucial feature to confer to IONP biocompatibility.

  1. Iron oxide nanoparticles surface coating and cell uptake affect biocompatibility and inflammatory responses of endothelial cells and macrophages

    Energy Technology Data Exchange (ETDEWEB)

    Orlando, Antonina [University of Milano-Bicocca, Department of Health Sciences (Italy); Colombo, Miriam; Prosperi, Davide [University of Milano-Bicocca, Department of Biotechnology and Biosciences (Italy); Gregori, Maria; Panariti, Alice; Rivolta, Ilaria; Masserini, Massimo; Cazzaniga, Emanuela, E-mail: emanuela.cazzaniga@unimib.it [University of Milano-Bicocca, Department of Health Sciences (Italy)

    2015-09-15

    Engineered iron oxide nanoparticles (IONP) offer the possibility of a wide range of medical uses, from clinical imaging to magnetically based hyperthermia for tumor treatment. These applications require their systemic administration in vivo. An important property of nanoparticles is their stability in biological media. For this purpose, a multicomponent nanoconstruct combining high colloidal stability and improved physical properties was synthesized and characterized. IONP were coated with an amphiphilic polymer (PMA), which confers colloidal stability, and were pegylated in order to obtain the nanoconstruct PEG-IONP-PMA. The aim of this study was to utilize cultured human endothelial cells (HUVEC) and murine macrophages, taken as model of cells exposed to NP after systemic administration, to assess the biocompatibility of PEG-IONP-PMA (23.1 ± 1.4 nm) or IONP-PMA (15.6 ± 3.4 nm). PEG-IONP-PMA, tested at different concentrations as high as 20 μg mL{sup −1}, exhibited no cytotoxicity or inflammatory responses. By contrast, IONP-PMA showed a concentration-dependent increase of cytotoxicity and of TNF-α production by macrophages and NO production by HUVECs. Cell uptake analysis suggested that after PEGylation, IONP were less internalized either by macrophages or by HUVEC. These results suggest that the choice of the polymer and the chemistry of surface functionalization are a crucial feature to confer to IONP biocompatibility.

  2. A hybrid two-component system of Tannerella forsythia affects autoaggregation and post-translational modification of surface proteins.

    Science.gov (United States)

    Niwa, Daisuke; Nishikawa, Kiyoshi; Nakamura, Hiroshi

    2011-05-01

    Tannerella forsythia is a Gram-negative oral anaerobe closely associated with both periodontal and periapical diseases. The ORF TF0022 of strain ATCC 43037 encodes a hybrid two-component system consisting of an N-terminal histidine kinase and a C-terminal response regulator. Disruption of the TF0022 locus enhanced autoaggregation of the broth-cultured cells. Comparative proteome analyses revealed that two S-layer proteins in the TF0022 mutant exhibited decreased apparent masses by denaturing gel electrophoresis, suggesting a deficiency in post-translational modification. Furthermore, the mutant decreased the production of a glycosyltransferase encoded by TF1061 that is located in a putative glycosylation-related gene cluster. Quantitative real-time PCR revealed reduced transcription of TF1061 and the associated genes in the TF0022 mutant. These results indicate that TF0022 upregulates the expression of the glycosylation-related genes and suggest modulation of the autoaggregation of T. forsythia cells by a possible post-translational modification of cell-surface components.

  3. Regulation of leaf photosynthetic rate correlating with leaf carbohydrate status and activation state of Rubisco under a variety of photosynthetic source/sink balances.

    Science.gov (United States)

    Kasai, Minobu

    2008-09-01

    There is evidence suggesting that in plants changes in the photosynthetic source/sink balance are an important factor that regulates leaf photosynthetic rate through affects on the leaf carbohydrate status. However, to resolve the regulatory mechanism of leaf photosynthetic rate associated with photosynthetic source/sink balance, information, particularly on mutual relationships of experimental data that are linked with a variety of photosynthetic source/sink balances, seems to be still limited. Thus, a variety of manipulations altering the plant source/sink ratio were carried out with soybean plants, and the mutual relationships of various characteristics such as leaf photosynthetic rate, carbohydrate content and the source/sink ratio were analyzed in manipulated and non-manipulated control plants. The manipulations were removal of one-half or all pods, removal of one-third or two-third leaves, and shading of one-third or one-half leaves with soybean plants grown for 8 weeks under 10 h light (24 degrees C) and 14 h darkness (17 degrees C). It was shown that there were significant negative correlations between source/sink ratio (dry weight ratio of attached leaves to other all organs) and leaf photosynthetic rate; source/sink ratio and activation ratio (percentage of initial activity to total activity) of Rubisco in leaf extract; leaf carbohydrate (sucrose or starch) content and photosynthetic rate; carbohydrate (sucrose or starch) content and activation ratio of Rubisco; amount of protein-bound ribulose-1,5-bisphosphate (RuBP) in leaf extract and leaf photosynthetic rate; and the amount of protein-bound RuBP and activation ratio of Rubisco. In addition, there were significant positive correlations between source/sink ratio and leaf carbohydrate (sucrose or starch) content; source/sink ratio and the amount of protein-bound RuBP; carbohydrate (sucrose or starch) content and amount of protein-bound RuBP and the activation ratio of Rubisco and leaf photosynthetic rate

  4. Photosynthetic leaf area modulates tiller bud outgrowth in sorghum.

    Science.gov (United States)

    Kebrom, Tesfamichael H; Mullet, John E

    2015-08-01

    Shoot branches or tillers develop from axillary buds. The dormancy versus outgrowth fates of buds depends on genetic, environmental and hormonal signals. Defoliation inhibits bud outgrowth indicating the role of leaf-derived metabolic factors such as sucrose in bud outgrowth. In this study, the sensitivity of bud outgrowth to selective defoliation was investigated. At 6 d after planting (6 DAP), the first two leaves of sorghum were fully expanded and the third was partially emerged. Therefore, the leaves were selectively defoliated at 6 DAP and the length of the bud in the first leaf axil was measured at 8 DAP. Bud outgrowth was inhibited by defoliation of only 2 cm from the tip of the second leaf blade. The expression of dormancy and sucrose-starvation marker genes was up-regulated and cell cycle and sucrose-inducible genes was down-regulated during the first 24 h post-defoliation of the second leaf. At 48 h, the expression of these genes was similar to controls as the defoliated plant recovers. Our results demonstrate that small changes in photosynthetic leaf area affect the propensity of tiller buds for outgrowth. Therefore, variation in leaf area and photosynthetic activity should be included when integrating sucrose into models of shoot branching.

  5. Growth Performance of Clarias Gariepinus Fed Soaked Moringa Oleifera Leaf Meal

    Directory of Open Access Journals (Sweden)

    Ayegba, E. O

    2016-06-01

    Full Text Available The present study evaluates the nutritional potential of soaked-dried Moringa oleifera leaf meal in the diet of Clarias gariepinus. Four isonitrogenous (35% crude protein diets were formulated with Moringa leaf replacing soybean meal at 0%, 10%, 20% and 30%. Result obtained revealed declined in weight gain, specific growth rate, feed conversion efficiency, protein efficiency ratio and apparent net protein utilization as dietary replacement of Moringa leaf meal increased beyond 10%. It is concluded that Moringa oleifera leaf meal can replace soybeans meal up to 10% without affecting the growth performance of African catfish.

  6. Study on adhesively-bonded surface of tapered double cantilever specimen made of aluminum foam affected with shear force

    Institute of Scientific and Technical Information of China (English)

    孙洪鹏; CHO Jae-ung

    2015-01-01

    Aluminum foam is widely used in diverse areas to minimize the weight and maximize the absorption of shock energy in lightweight structures and various bio-materials. It presents a number of advantages, such as low density, incombustibility, non-rigidity, excellent energy absorptivity, sound absorptivity and low heat conductivity. The aluminum foam with an air cell structure was placed under the TDCB Mode II tensile load by using Landmark equipment manufactured by MTS to examine the shear failure behavior. The angle of the tapered adhesively-bonded surfaces of specimens was designated as a variable, and three models were developed with the inclined angles differing from one another at 6°, 8° and 10°. The specimens with the inclined angles of 6°, 8° and 10° have the maximum reaction forces of 168 N, 194 N when the forced displacements are 6, 5 and 4.2 mm respectively. There are three specimens with the inclined angles of 10°, 8° and 6° in the order of maximum reaction force. As the analysis result, the maximum equivalent stresses of 0.813 MPa and 0.895 MPa happened when the forced displacements of 6 mm and 5 mm proceeded at the models of 6° and 8°, respectively. A simulation was carried out on the basis of finite element method and the experimental design. The results of the experiment and the simulation analysis are shown not different from each other significantly. Thus, only a simulation could be confirmed to be performed in substitution of an experiment, which is costly and time-consuming in order to determine the shearing properties of materials made of aluminum foam with artificial data.

  7. Distribution and factors affecting adsorption of sterols in the surface sediments of Bosten Lake and Manas Lake, Xinjiang.

    Science.gov (United States)

    Liu, Jiang; Yao, Xiaorui; Lu, Jianjiang; Qiao, Xiuwen; Liu, Zilong; Li, Shanman

    2016-03-01

    This study investigated the concentrations and distribution of eight sterol compounds in the surface sediments of Bosten Lake and Manas Lake, Xinjiang, China. The ratios of sterols as diagnostic indices were used to identify pollution sources. The sediment of the two lakes was selected as an adsorbent to investigate the adsorption behaviour of sterols. Results showed that the sterols were widely distributed in the sediments of the lakes in the study areas. The total concentrations of the detected sterols in Bosten Lake and in Manas Lake were 1.584-27.897 and 2.048-18.373 μg g(-1)∙dw, respectively. In all of the sampling sites, the amount of faecal sterols was less than that of plant sterols. β-sitosterol was the dominant plant sterol with a mean concentration of 2.378 ± 2.234 μg g(-1)∙dw; cholesterol was the most abundant faecal sterol with a mean concentration of 1.060 ± 1.402 μg g(-1)∙dw. The pollution level was higher in Bosten Lake than in Manas Lake. Majority of the ratios clearly demonstrated that the contamination by human faecal sources was occurring at stations which are adjacent to residential areas and water inlets. The adsorption behaviour of sterols to sediment suggested that the sterol adsorption coefficients were reduced as temperature increased. As salinity increased, the adsorption quantity also increased. As pH increased, the sediment adsorption of sterol slightly increased because the strong alkaline solution is not conducive to the adsorption of sterols. The ratios between sterols did not change largely with the change in external factors.

  8. DOE-EMSP Final Report: Characterization of Changes in Colloid and DNAPL Affecting Surface Chemistry and Remediation

    Energy Technology Data Exchange (ETDEWEB)

    Susan E. Powers; Stefan J. Grimberg; Miles Denham

    2007-02-07

    The waste disposal to the M-area basin and A-14 outfall at the Savannah River Department of Energy facility in Aiken SC (USA) included a wide variety of inorganic aqueous flows and organic solvents in the form of dense non-aqueous phase liquids (DNAPL). The DNAPL has migrated through the subsurface resulting in widespread groundwater contamination. The goal of this research was to identify and quantify processes that could have affected the migration and remediation of the DNAPL in the subsurface. It was hypothesized that the variety of waste disposed at this site could have altered the mineral, microbial and DNAPL properties at this site relative to other DNAPL sites. The DNAPL was determined to have a very low interfacial tension and is suspected to be distributed in fine grained media, thereby reducing the effectiveness of soil vapor extraction remediation efforts. Although the DNAPL is primarily comprised of tetrachloroethene and trichloroethane, it also contains organic acids and several heavy metals. Experimental results suggest that iron from the aqueous and DNAPL phases undergoes precipitation and dechlorination reactions at the DNAPL-water interface, contributing to the low interfacial tension and acidity of the DNAPL. Biological activity in the contaminated region can also contribute to the low interfacial tension. PCE degrading bacteria produce biosurfactants and adhere to the DNAPL-water interface when stressed by high tetrachloroethene or low dissolved oxygen concentrations. The presence of iron can reduce the interfacial tension by nearly an order of magnitude, while the PCE degraders reduced the interfacial tension by nearly 50%. Abiotic changes in the mineral characteristics were not found to be substantially different between contaminated and background samples. The research completed here begins to shed some insight into the complexities of DNAPL fate and migration at sites where co-disposal of many different waste products occurred. Quantifying

  9. Leaf Relative Water Content Estimated from Leaf Reflectance and Transmittance

    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. In the research we report here, we used optical polarization techniques to monitor the 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 change nonlinearly. The result show that the nonlinearities cancel in the ratio R/T, which appears linearly related to RWC for RWC less than 90%. The results suggest that potentially leaf water status and perhaps even canopy water status could be monitored starting from leaf and canopy optical measurements.

  10. Dry deposition of acidic air pollutants to tree leaves, determined by a modified leaf-washing technique

    Science.gov (United States)

    Watanabe, Mirai; Takamatsu, Takejiro; Koshikawa, Masami K.; Yamamura, Shigeki; Inubushi, Kazuyuki

    Dry deposition fluxes ( FL) of NO 3- and SO 42- to leaf surfaces were measured for Japanese red pine ( Pinus densiflora), Japanese cedar ( Cryptomeria japonica), Japanese cypress ( Chamaecyparis obtusa), and Japanese white oak ( Quercus myrsinaefolia), together with atmospheric concentrations ( CL) of NO x (NO + NO 2), T-NO 3 (gaseous HNO 3 + particulate NO 3-) and SO x (gaseous SO 2 + particulate SO 42-) around the leaves in a suburban area of Japan, using a modified leaf-washing technique. FL of NO 3- and SO 42- decreased as follows: pine >> cedar > cypress ≥ oak and pine >> cedar > oak ≥ cypress, respectively. FL of NO 3- for all tree species fluctuated synchronously with CL of T-NO 3. FL of SO 42- fluctuated with CL of SO x, but the dominant pollutant deposited (SO 2 or SO 42-) appeared to differ for different tree species. Dry deposition conductance ( KL) of T-NO 3 and SO x was derived as an FL/ CL ratio. Seasonal variations of KL likely reflect the gas/particle ratios of T-NO 3 and SO x, which were affected by meteorological conditions such as temperature. Dry deposition velocities ( Vd) of T-NO 3 and SO x were obtained as the mathematical product of annual mean KL and the total leaf surface areas in the forests. The comparison of Vd among tree species indicated that the loads of acidic air pollutants were higher to coniferous forests than broad-leaved forest because of the higher KL and/or larger leaf surface areas.

  11. Pinot noir wine volatile and anthocyanin composition under different levels of vine fruit zone leaf removal.

    Science.gov (United States)

    Feng, Hui; Skinkis, Patricia A; Qian, Michael C

    2017-01-01

    The impacts of fruit zone leaf removal on volatile and anthocyanin compositions of Pinot noir wine were investigated over two growing seasons. Wine volatiles were analyzed by multiple techniques, including headspace solid phase microextraction-GC-MS (HS-SPME-GC-MS), headspace-GC-FID (HS-GC-FID) and stir bar sorptive extraction-GC-MS (SBSE-GC-MS). Fruit zone leaf removal affected the concentration of many grape-derived volatile compounds such as terpene alcohols and C13-norisoprenoids in wine, although the degree of impact depended on the vintage year and severity of leaf removal. Fruit zone leaf removal resulted in greater concentrations of linalool, α-terpineol and β-damascenone but had no impact on other terpene alcohols or β-ionone. Fruit zone leaf removal had no consistent impact on C6 alcohols, volatile phenols, lactones, fermentation-derived alcohols, acids, or most esters. Fruit zone leaf removal increased anthocyanins in final wine.

  12. Leaf Epidermal Cells: A Trap for Lipophilic Xenobiotics

    Institute of Scientific and Technical Information of China (English)

    Zhiqian Liu

    2006-01-01

    Plant surfaces are covered by a layer of cuticle, which functions as a natural barrier to protect plants from mechanical damage, desiccation, and microbial invasion. Results presented in this report show that the epicuticular wax and the cuticle of plant leaves also play an important role in resisting xenobiotic invasion.Although the epicuticular wax is impermeableto hydrophilic xenobiotics, the cuticle not only restricts the penetration of hydrophilic compounds into leaf cells, but also traps lipophilic ones. The role of the epidermal cells of plant leaves in resisting xenobiotic invasion has been neglected until now. The present study shows, for the first time, that the epidermal cells may reduce or retard the transport of lipophilic xenobiotics into the internal tissues through vacuolar sequestration. Although the guard cells appear to be an easy point of entry for xenobiotics, only a very small proportion of xenobiotics present on the leaf surface actually moves into leaf tissues via the guard cells.

  13. 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.

  14. 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.

  15. Shear Wave Velocity Profiles Determined from Surface Wave Measurements at Sites Affected by the August 15th, 2007 Earthquake in Peru

    Science.gov (United States)

    Rosenblad, B. L.; Bay, J. A.

    2008-05-01

    The shear wave velocity (Vs) profile of near-surface soils is a critical parameter for understanding recorded ground motions and predicting local site effects in an earthquake. In structural design, the Vs profile in the top 30 m is used to modify design response spectra to account for local soil effects. In addition, knowledge of the near- surface Vs profile at strong motion stations can be used to account for changes in frequency content and amplification caused by the local site conditions. Following the August 15th, 2007 earthquake in Peru, a field testing program was performed to measure Vs profiles in the top 20 to 30 m at twenty-two locations in the affected region. The measurements were performed primarily at the sites of damaged school buildings but were also performed at several strong motion station sites as well as a few locations where evidence of soil liquefaction was observed. Nineteen of the sites were located in the severely affected cities of Chincha, Ica, Pisco and Tambo de Mora, with the remaining three sites located in, Lima, Palpa and Paracus. The Vs profiles were determined from surface wave velocity measurements performed with an impact source. The objective of this paper is to present and discuss the range of Vs profile conditions encountered in the regions affected by the Pisco-Peru earthquake. In the city of Ica, the profiles generally exhibited gradually increasing velocities with depth, with velocities which rarely exceeded 400 m/s in the top 30 m. In contrast, the profiles measured in Pisco, often exhibited strong, shallow velocity contrasts with Vs increasing from less than 200 m/s at the surface to over 600 m/s at some sites. The profiles measured in Chincha generally fell in between the ranges measured in Ica and Pisco. Lastly, soil liquefaction was evident throughout Tambo de Mora on the coast of Peru. Measurements indicated very low shear wave velocities of 75 to 125 m/s in the top 4 m, which is consistent with the observed

  16. TURCICUM LEAF BLIGHT OF MAIZE INCITED BY Exserohilum turcicum: A REVIEW

    Directory of Open Access Journals (Sweden)

    T. Rajeshwar Reddy

    2014-03-01

    Full Text Available Globally maize (Zea mays L. is the first and most important cereal crop gown under diversity of environments unmatched by any other crop, as expansion of maize to new areas and environment still continues due to its range of plasticity. It is prone to as many as 112 diseases in different parts of the world, caused by fungi, bacteria, viruses and nematodes leading to extensive damage. In India about 61 diseases have been reported to affect the crop. These include seedling blights, stalk rots, foliar diseases, downy mildews and ear rots (Payaket al., 1973 and Payak and Sharma, 1985.Among the fungal diseases turcicum leaf blight caused by Exserohilum turcicum (Pass.. Leonard and Suggs. (Synonyms:Helminthosprium turcicum (Pass. Leonard and Suggs [Perfect stage: Setosphaeria turcica (Luttrell Leonard and Suggs. (Synonym: Trichometasphaeria turcica (Luttrell] is one the important foliar disease causing severe reduction in grain and fodder yield to the tune of 16 -98% (Kachapur and Hegde, 1988. The disease was first described by Passerini (1876 from Italy and by Butler (1907 from India. In India, this disease is prevalent in Andhra Pradesh, Karnataka, Bihar, Himachal Pradesh and Maharashtra. Turcicum leaf blight is potentially an important foliar disease in areas where the temperatures drop at night while the humidity is high. The disease is known to affect maize from seedling stage till harvest. Loss in grain yield will be more if it occurs at flowering, silking and grain filling stages. Lesions produced on the leaves of susceptible plants are normally large (4 -20 cm long and 1-5 cm wide, elliptical in shape and greyish green to tan in color, in conditions of high relative humidity, lesions may be covered with masses of dark conidia of the fungus. The conidia are olive grey and spindle shaped with 1- 9 septations. These conidia spread through air germinate on the surface and penetrate directly. Turcicum blight injures or kills the leaf tissues and

  17. Leaf Positioning of Arabidopsis in Response to Blue Light

    Institute of Scientific and Technical Information of China (English)

    Shin-ichiro Inoue; Toshinori Kinoshita; Atsushi Takemiya; Michio Doi; Ken-ichiro Shimazaki

    2008-01-01

    Appropriate leaf positioning is essential for optimizing photosynthesis and plant growth. However, it has not been elucidated how green leaves reach and maintain their position for capturing light. We show here the regulation of leaf positioning under blue light stimuli. When 1-week-old Arabidopsis seedlings grown under white light were transferred to red light (25 μmol m-2s-t) for 5 d, new petioles that appeared were almost horizontal and their leaves were curled and slanted downward. However, when a weak blue light from above (0.1 μmol m-2s-1) was superimposed on red light, the new petioles grew obliquely upward and the leaves were flat and horizontal. The leaf positioning required both phototropin1 (phot1) and nonphototropic hypocotyl 3 (NPH3), and resulted in enhanced plant growth. In an nph3 mutant, neither optimal leaf positioning nor leaf flattening by blue light was found, and blue light-induced growth enhancement was drastically reduced. When blue light was increased from 0.1 to 5 μmol m-2s-1, normal leaf positioning and leaf flattening were induced in both phot1 and nph3 mutants, suggesting that phot2 signaling became functional and that the signaling was independent of phot1 and NPH3 in these responses. When plants were irradiated with blue light (0.1 μmol m-2s-1) from the side and red light from above, the new leaves became oriented toward the source of blue light. When we transferred these plants to both blue light and red light from above, the leaf surface changed its orientation to the new blue light source within a few hours, whereas the petioles initially were unchanged but then gradually rotated, suggesting the plasticity of leaf positioning in response to blue light. We showed the tissue expression of NPH3 and its plasma membrane localization via the coiled-coil domain and the C-terminal region. We conclude that NPH3-mediated phototropin signaling optimizes the efficiency of light perception by inducing both optimal leaf positioning and leaf

  18. On modeling and nanoanalysis of caries-affected dentin surfaces restored with Zn-containing amalgam and in vitro oral function.

    Science.gov (United States)

    Toledano, Manuel; Aguilera, Fátima S; Osorio, Estrella; López-López, Modesto T; Cabello, Inmaculada; Toledano-Osorio, Manuel; Osorio, Raquel

    2015-12-19

    The aim of this research was to assess the influence of mechanical loading on the ability of Zn-free versus Zn-containing amalgams to promote remineralization at the dentin interface. Sound and caries-affected dentin surfaces (CAD) were restored using Zn-free or Zn-containing dental amalgams. Midcoronal dentin surfaces were studied by (1) atomic force microscopy analysis (including plot and phase imaging, nanoindentation test [modulus of Young (Ei), nanoroughness measurements, and fibril diameter assessment], (2) Raman spectroscopy/cluster analysis, (3) x-ray diffraction, (4) field emission electron microscope and energy-dispersive analysis, for morphological, mechanical, and physicochemical characterization. Analyses were performed before amalgam placement and after amalgam removal, at 24 h and 3 weeks of load cycling. Zn-free and Zn-containing amalgams restorations promoted an increase in the modulus of Young of CAD surfaces, after 3 weeks of load cycling; at this time, Zn-containing amalgams attained higher Ei than Zn-free restorations. Zn-containing amalgams induced tubular occlusion after load cycling, in both sound and CAD. Zn free-amalgams promoted remineralization of both intertubular and peritubular dentin in CAD substrata. These minerals were identified as calcium-phosphate deposits and crystals as hydroxyl-apatite with augmented crystallographic maturity but with some components of lattice distortion. Crosslinking of collagen diminished and secondary structure of collagen increased in CAD substrate restored with Zn-containing amalgam after 3 weeks of load cycling, indicating an advanced preservation, molecular organization, and orientation of collagen fibrils after load cycling. Plot and phase images permitted to observe the topographical changes which were promoted by the mineral deposits; in general, the indexes related to higher remineralization gave rise to a decrease of nanoroughness and an augmentation of the bandwidth of the collagen fibrils. Zn

  19. Genetics of Ophraella leaf beetles

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This proposal is to collect samples of each species of Ophraella leaf beetle encountered, not to exceed 50 specimens per species, for genetic analysis using DNA...

  20. Agave Americana Leaf Fibers

    Directory of Open Access Journals (Sweden)

    Ashish Hulle

    2015-02-01

    Full Text Available The growing environmental problems, the problem of waste disposal and the depletion of non-renewable resources have stimulated the use of green materials compatible with the environment to reduce environmental impacts. Therefore, there is a need to design products by using natural resources. Natural fibers seem to be a good alternative since they are abundantly available and there are a number of possibilities to use all the components of a fiber-yielding crop; one such fiber-yielding plant is Agave Americana. The leaves of this plant yield fibers and all the parts of this plant can be utilized in many applications. The “zero-waste” utilization of the plant would enable its production and processing to be translated into a viable and sustainable industry. Agave Americana fibers are characterized by low density, high tenacity and high moisture absorbency in comparison with other leaf fibers. These fibers are long and biodegradable. Therefore, we can look this fiber as a sustainable resource for manufacturing and technical applications. Detailed discussion is carried out on extraction, characterization and applications of Agave Americana fiber in this paper.

  1. X-ray diffraction analysis and metal physics modeling of static strain aging and thermal dislocation recovery in the mechanically affected zone of surface finished hardened steel

    Energy Technology Data Exchange (ETDEWEB)

    Gegner, Juergen [SKF GmbH, Dept. of Material Physics, Schweinfurt (Germany)

    2009-07-01

    After heat treatment, finish machining of the hardened steel represents the last manufacturing step of machine elements. The practically most important operation of grinding is applied to achieve edge zone compressive residual stresses, best surface quality and dimensional accuracy. Metal removal involves high plastic deformation work. Glide and intersection processes raise the density and produce lower energy substructures of dislocations. The temperature and time behavior of post-machining thermal treatment is analyzed on ground and honed martensitic SAE 52100 rolling bearing steel. Microstructure stabilization is reflected in a large XRD line width decrease on the surface. The kinetics is modeled by rate-controlling carbide dissolution as the carbon source for Cottrell-type segregation at dislocations. This static strain aging is verified by the formation of a slight white etching surface layer. The metal physics model is extended to also consider superimposed thermal dislocation recovery. Both effects are separable. In rolling contact fatigue tests under mixed friction running conditions, air reheating of the samples below the tempering temperature, which avoids hardness loss, leads to a significant lifetime increase. Thermal post-treatment after cold working results in similar changes of the XRD line width in the larger mechanically affected edge zone.

  2. Plinia edulis - leaf architecture and scanning electron micrographs

    Directory of Open Access Journals (Sweden)

    Ana M. Donato

    2013-06-01

    Full Text Available Many species of Myrtaceae, including Plinia edulis (Vell. Sobral (cambucá, have pharmacological properties and are used as hypoglycemiants and therapeutic agents against stomach problems and throat infections. Samples were collected from Tijuca Forest in Rio de Janeiro, and the morpho-anatomical data were compared with other specimens obtained from Trindade, Paraty, found in the literature. Variations in leaf anatomy were observed, and the possible causes for these effects are discussed. The plant material collected from Tijuca Forest was analyzed using scanning electron and optical microscopy. Histochemical tests were applied to identify starch, lipids, phenolic compounds and lignin. The epidermal cells exhibit straight or slightly sinuous anticlinal walls covered by a smooth cuticle with granules of wax. Simple trichomes are restricted to the midrib region, and paracytic stomata are only observed on the abaxial leaf surface. The mesophyll is dorsiventral, with conspicuous intercellular spaces in the spongy parenchyma. Intercalated columns of crystalliferous cells and subepidermal secretory cavities are observed in the single layer of palisade parenchyma. The samples obtained from Trindade, Paraty, show larger leaves, anomocytic stomata and trichomes scattered throughout the leaf surface. This plasticity might reflect leaf adaptations to environmental factors or different stages of leaf development.

  3. Leaf micromorphology of some Phyllanthus L. species (Phyllanthaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Solihani, N. S., E-mail: noorsolihani@gmail.com; Noraini, T., E-mail: norainitalip@gmail.com [School of Environmental and Natural Resource Sciences Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Azahana, A., E-mail: bell-azahana@yahoo.com [Department of Plant Science, Kulliyyah of Science, International Islamic University Malaysia, Kuantan Campus, Kuantan, Pahang (Malaysia); Nordahlia, A. S., E-mail: nordahlia@frim.gov.my [Forest Research Institute of Malaysia, 52109 Kepong, Selangor (Malaysia)

    2015-09-25

    Comparative leaf micromorphological study was conducted of five chosen Phyllanthus L. (Phyllanthaceae) species, namely P. acidus L., P. elegans Wall. ex Müll. Arg., P. emblica L., P. urinaria L. and P. pulcher Wall. ex Müll. Arg. The objective of this study is to identify the leaf micromorphological characteristics that can be used in species identification. The procedures involve examination under scanning electron microscope. Findings of this study have demonstrated variations in the leaf micromorphological characteristics such as in the types of waxes present on adaxial and abaxial epidermis surfaces, in the stomata and types of trichome. Common character present in all species studied are the presence of a thin film layer and buttress-like waxes on epidermal leaf surfaces. Diagnostics characters found in this study are the presence of papilla in P. elegens, amphistomatic stomata in P. urinaria and flaky waxes in P. pulcher. The result of this study has shown that leaf micromorphological characters have some taxonomic significance and can be used in identification of species in the genus Phyllanthus.

  4. Wettability, Polarity, and Water Absorption of Holm Oak Leaves: Effect of Leaf Side and Age1[OPEN

    Science.gov (United States)

    Fernández, Victoria; Sancho-Knapik, Domingo; Guzmán, Paula; Peguero-Pina, José Javier; Gil, Luis; Karabourniotis, George; Khayet, Mohamed; Fasseas, Costas; Heredia-Guerrero, José Alejandro; Heredia, Antonio; Gil-Pelegrín, Eustaquio

    2014-01-01

    Plant trichomes play important protective functions and may have a major influence on leaf surface wettability. With the aim of gaining insight into trichome structure, composition, and function in relation to water-plant surface interactions, we analyzed the adaxial and abaxial leaf surface of holm oak (Quercus ilex) as a model. By measuring the leaf water potential 24 h after the deposition of water drops onto abaxial and adaxial surfaces, evidence for water penetration through the upper leaf side was gained in young and mature leaves. The structure and chemical composition of the abaxial (always present) and adaxial (occurring only in young leaves) trichomes were analyzed by various microscopic and analytical procedures. The adaxial surfaces were wettable and had a high degree of water drop adhesion in contrast to the highly unwettable and water-repellent abaxial holm oak leaf sides. The surface free energy and solubility parameter decreased with leaf age, with higher values determined for the adaxial sides. All holm oak leaf trichomes were covered with a cuticle. The abaxial trichomes were composed of 8% soluble waxes, 49% cutin, and 43% polysaccharides. For the adaxial side, it is concluded that trichomes and the scars after trichome shedding contribute to water uptake, while the abaxial leaf side is highly hydrophobic due to its high degree of pubescence and different trichome structure, composition, and density. Results are interpreted in terms of water-plant surface interactions, plant surface physical chemistry, and plant ecophysiology. PMID:24913938

  5. A method to improve leaf succulence quantification

    Directory of Open Access Journals (Sweden)

    André Mantovani

    1999-01-01

    Full Text Available Leaf succulence has important physiological and ecological implications. Currently it is quantified by Delf's index (fresh weight/leaf area and fresh weight/ dry weight ratio. Both indeces are reconsidered and a new index is proposed. Shade and sun leaves from terrestrial, hemiepiphytic and epiphytic aroids were studied. Delf's formula, which does not consider dry weight, overestimated leaf succulence. As fresh weight / dry weight ratio (fw / dw does not consider leaf area, plants with the same fw / dw ratio were more than five times different in area. The last case was only possible with a decrease in surface / volume ratio and a increase of mesophyll thickness, components not measured by fw / dw ratio. The new index proposed here, which takes into consideration dry weight and leaf area, showed a high correlation to mesophyll thickness.A suculência foliar tem importantes implicações fisiológicas e ecológicas. Usualmente é quantificada pelo índice de Delf (1912 (peso fresco / area foliar e pela razão peso fresco / peso seco. Estes dois índices são reconsiderados e um novo índice é proposto. Folhas de sombra e sol de aráceas terrestres, hemiepífitas e epífitas foram analisadas. A fórmula de Delf, por não considerar o peso seco das folhas, superestimou a suculência foliar. Como a razão peso fresco / peso seco (pf / ps não leva em consideração a área das folhas, plantas com a mesma razão pf / ps foram mais de cinco vezes diferentes em relação à area foliar. Este último caso só é possível com a redução da razão superfície / volume e com o aumento da espessura do mesofilo, componentes não considerados pela razão pf / ps. O novo índice aqui proposto, que leva em consideração tanto o peso seco das folhas quanto as suas respectivas áreas, mostrou uma alta correlação com a espessura do mesofilo.

  6. Differential response of pitted morning glory and ivy leaf morning glory to acifluorfen, fomesafen, and lactofen

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, J.M.

    1987-01-01

    Field and laboratory investigations were conducted to examine the response of soybeans (Glycine max (L.) Merr.), pitted morning glory (Ipomoea lacunosa L.number/sup 1/ IPOLA), and ivy leaf morning glory (Ipomoea hederacea (L.) Jacq. number IPOHE) to acifluorfen, fomesafen, and lactofen. In field studies, greatest soybean injury was observed with acifluorfen and lactofen. All treatments provided 80% or greater control of pitted morning glory 15 days after treatment. Only acifluorfen and fomesafen at 0.6 kg ai ha/sup -1/ provided 80% or greater ivy leaf morning glory. The differential response of pitted morning glory and ivy leaf morning glory to these diphenyl ether herbicides was reflected in soybean seed yields. In laboratory studies, 71 to 84% of applied /sup 14/C-acifluorfen was not absorbed into the leaf surface of ivy leaf morning glory. Thirty-two to 46% of applied acifluorfen was recovered from the leaf surface of pitted morning glory. Sixty-four percent of applied /sup 14/C-lactofen was recovered from leaf surfaces of both morning glory species 96 h after treatment. Treated leaves of pitted morning glory contained 35 to 37% more /sup 14/C-acifluorfen than ivy leaf morning glory. Less than 28% of applied /sup 14/C-lactofen was absorbed into treated leaves of both morning glory species at 24, 48, and 96 h harvests.

  7. Nutrients concentrations in the flag leaf and grains of black-oat affected by phosphate and potassium fertilization / Teores de nutrientes da folha bandeira e grãos de aveia-preta em função da adubação fosfatada e postássica

    Directory of Open Access Journals (Sweden)

    Claudemir Zucareli

    2009-12-01

    Full Text Available A aveia-preta (Avena strigosa Schreber tem sido comumente utilizada para adubação verde, rotação de culturas no sistema de plantio direto, em cultivo no outono-inverno e ainda, para pastejo, fenação e ensilagem. O objetivo deste trabalho foi avaliar os teores de macro e micronutrientes da folha bandeira e dos grãos de aveia-preta cv. Comum em função da adubação fosfatada e potássica. O experimento foi realizado em condições de campo, em Nitossolo Vermelho, em Botucatu-SP. Os tratamentos constaram de três doses de superfosfato simples (0, 40 e 80 kg ha-1 de P2O5 e três doses de cloreto de potássio (0, 20 e 40 kg ha-1 de K2O dispostos em esquema fatorial (3 x 3, sob o delineamento de blocos casualizados, com quatro repetições. A adubação foi feita no sulco de semeadura. Em todas as parcelas foi aplicado sulfato de amônio, sendo 20 kg ha-1 de N na semeadura e 30 kg ha-1 em cobertura no final do perfilhamento. Os teores de Ca, Mg, S, Fe, Mn, Cu e Zn da folha bandeira e de P e K dos grãos foram influenciados pela adubação fosfatada. A adubação potássica não influenciou os teores de macro e micronutrientes da folha bandeira e dos grãos em aveia preta.The black oat (Avena strigosa Schreber has been commonly used as green manure, in crop rotation systems under no-tillage, fall-winter crop, and for cattle grazing, hay, and silage. The objective of this work was to evaluate the nutrient concentrations in the flag leaf and grains of black-oat affect by phosphate and potassium fertilization. The experiment was carried out under field conditions on a Rhodic Nitosol, in Botucatu, São Paulo State, Brazil. Three doses of single superphosphate (0, 40 and 80 kg.ha-1 of P2O5 and three of potassium chloride (0, 20 and 40 kg ha-1 of K2O were tested as a factorial (3 x 3, in a randomized complete block design, with four replicates. The fertilizers were applied in the sowing row. Ammonium sulphate was supplied for all plots (20 kg ha-1

  8. The Effect of Epidermal Structures on Leaf Spectral Signatures of Ice Plants (Aizoaceae

    Directory of Open Access Journals (Sweden)

    René Hans-Jürgen Heim

    2015-12-01

    Full Text Available Epidermal structures (ES of leaves are known to affect the functional properties and spectral responses. Spectral studies focused mostly on the effect of hairs or wax layers only. We studied a wider range of different ES and their impact on spectral properties. Additionally, we identified spectral regions that allow distinguishing different ES. We used a field spectrometer to measure ex situ leaf spectral responses from 350 nm–2500 nm. A spectral library for 25 species of the succulent family Aizoaceae was assembled. Five functional types were defined based on ES: flat epidermal cell surface, convex to papillary epidermal cell surface, bladder cells, hairs and wax cover. We tested the separability of ES using partial least squares discriminant analysis (PLS-DA based on the spectral data. Subsequently, variable importance (VIP was calculated to identify spectral regions relevant for discriminating our functional types (classes. Classification performance was high, with a kappa value of 0.9 indicating well-separable spectral classes. VIP calculations identified six spectral regions of increased importance for the classification. We confirmed and extended previous findings regarding the visible-near-infrared spectral region. Our experiments also confirmed that epidermal leaf traits can be classified due to clearly distinguishable spectral signatures across species and genera within the Aizoaceae.

  9. Leaf-age effects on seasonal variability in photosynthetic parameters and its relationships with leaf mass per area and leaf nitrogen concentration within a Pinus densiflora crown.

    Science.gov (United States)

    Han, Qingmin; Kawasaki, Tatsuro; Nakano, Takashi; Chiba, Yukihiro

    2008-04-01

    In the temperate zone of Japan, Pinus densiflora Sieb. et Zucc. bears needles of up to three age classes in the upper crown and up to five age classes in the lower crown. To elucidate the effects of leaf age on photosynthetic parameters and its relationships with leaf mass per unit area (LMA) and leaf nitrogen (N(l)) concentration on an area (N(a)) and mass (N(m)) basis, we measured seasonal variations in LMA, N(l), light-saturated photosynthetic rate (A(max)), stomatal conductance (g(s)), maximum rate of carboxylation (V(cmax)) and maximum rate of electron transport (J(max)) in leaves of all age classes in the upper and lower crown. Leaf mass per unit area increased by 27% with increasing leaf age in the lower crown, but LMA did not depend on age in the upper crown. Leaf age had a significant effect on N(m) but not on N(a) in both crown positions, indicating that decreases in N(m) resulted from dilution. Photosynthetic parameters decreased significantly with leaf age in the lower crown (39% for A(max) and 43% for V(cmax)), but the effect of leaf age was not as great in the upper crown, although these parameters exhibited seasonal variation in both crown positions. Regression analysis indicated a close relationship between LMA and N(a), regardless of age class or when each age class was pooled (r(2) = 0.57-0.86). Relationships between LMA and N(a) and among A(max), V(cmax) and J(max) were weak or not significant when all age classes were examined by regression analysis. However, compared with older leaves, relationships among LMA, N(a) and A(max) were stronger in younger leaves. These results indicate that changes in LMA and N(l) mainly reflect light acclimation during leaf development, but they are only slightly affected by irradiance in mature leaves. In conclusion, LMA and N(l) are useful parameters for estimating photosynthetic capacity, but age-related effects need to be taken into account, especially in evergreen conifers.

  10. Temperature effect on leaf water deuterium enrichment and isotopic fractionation during leaf lipid biosynthesis: results from controlled growth of C3 and C4 land plants.

    Science.gov (United States)

    Zhou, Youping; Grice, Kliti; Chikaraishi, Yoshito; Stuart-Williams, Hilary; Farquhar, Graham D; Ohkouchi, Naohiko

    2011-02-01

    The hydrogen isotopic ratios ((2)H/(1)H) of land plant leaf water and the carbon-bound hydrogen of leaf wax lipids are valuable indicators for climatic, physiological, metabolic and geochemical studies. Temperature will exert a profound effect on the stable isotopic composition of leaf water and leaf lipids as it directly influences the isotopic equilibrium (IE) during leaf water evaporation and cellular water dissociation. It is also expected to affect the kinetics of enzymes involved in lipid biosynthesis, and therefore the balance of hydrogen inputs along different biochemical routes. We conducted a controlled growth experiment to examine the effect of temperature on the stable hydrogen isotopic composition of leaf water and the biological and biochemical isotopic fractionations during lipid biosynthesis. We find that leaf water (2)H enrichment at 20°C is lower than that at 30°C. This is contrary to the expectation that at lower temperatures leaf water should be more enriched in (2)H due to a larger equilibrium isotope effect associated with evapotranspiration from the leaf if all other variables are held constant. A hypothesis is presented to explain the apparent discrepancy whereby lower temperature-induced down-regulation of available aquaporin water channels and/or partial closure of transmembrane water channel forces water flow to "detour" to a more convoluted apoplastic pathway, effectively increasing the length over which diffusion acts against advection as described by the Péclet effect (Farquhar and Lloyd, 1993) and decreasing the average leaf water enrichment. The impact of temperature on leaf water enrichment is not reflected in the biological isotopic fractionation or the biochemical isotopic fractionation during lipid biosynthesis. Neither the biological nor biochemical fractionations at 20°C are significantly different from that at 30°C, implying that temperature has a negligible effect on the isotopic fractionation during lipid biosynthesis.

  11. Antioxidant power of phytochemicals from Psidium guajava leaf.

    Science.gov (United States)

    Qian, He; Nihorimbere, Venant

    2004-06-01

    Dried ground leaves of Psidium guajava L. (guava) were extracted by water and aqueous ethyl alcohol 50% (1:10) ratio, and the total phenolic content in the extracts was determined spectrophotometrically according to Folin- Ciocalteu's phenol method and calculated as gallic acid equivalent (GAE). Remarkably high total phenolic content 575.3 +/-15.5 and 511.6+/-6.2 mg of GAE/g of dried weight material (for ethanol guava leaf extracts and water guava leaf extracts, respectively) were obtained. The antioxidant activity of lyophilized extracts was determined at ambient temperature by means of a 2,2-diphenyl-1-picrylhydryzyl (DPPH*) colorimetry with detection scheme at 515 nm. The activity was evaluated by the decrease in absorbance as the result of DPPH* color change from purple to yellow. The higher the sample concentration used, the stronger was the free radical-scavenging effect. The results obtained showed that ascorbic acid was a substantially more powerful antioxidant than the extracts from guava leaf. On the other hand, the commercial guava leaf extracts and ethanol guava leaf extracts showed almost the same antioxidant power whereas water guava leaf extracts showed lower antioxidant activity. The parameter EC(50) and the time needed to reach the steady state to EC(50) concentration (T(EC(50))) affected the antiradical capacity of the sample. The antioxidant efficiency (AE) has been shown to be a more adequate parameter for selecting antioxidants than the widely used EC(50). This study revealed that guava leaf extracts comprise effective potential source of natural antioxidants.

  12. Antioxidant power of phytochemicals from Psidium guajava leaf

    Institute of Scientific and Technical Information of China (English)

    钱和; NIHORIMBEREVenant

    2004-01-01

    Dried ground leaves ofPsidium guajava L. (guava) were extracted by water and aqueous ethyl alcohol 50%(1:10) ratio, and the total phenolic content in the extracts was determined spectrophotometrically according to FolinCiocalteu's phenol method and calculated as gallic acid equivalent (GAE). Remarkably high total phenolic content 575.3±15.5 and 511.6±6.2 mg of GAE/g of dried weight material (for ethanol guava leaf extracts and water guava leaf extracts,respectively) were obtained. The antioxidant activity of lyophilized extracts was determined at ambient temperature by means of a 2,2-diphenyl-1-picrylhydryzyl (DPPH') colorimetry with detection scheme at 515 nm. The activity was evaluated by the decrease in absorbance as the result of DPPH" color change from purple to yellow. The higher the sample concentration used, the stronger was the free radical-scavenging effect. The results obtained showed that ascorbic acid was a substantially more powerful antioxidant than the extracts from guava leaf. On the other hand, the commercial guava leaf extracts and ethanol guava leaf extracts showed almost the same antioxidant power whereas water guava leaf extracts showed lower antioxidant activity. The parameter EC50 and the time needed to reach the steady state to EC50 concentration (TEC50) affected the antiradical capacity of the sample. The antioxidant efficiency (AE) has been shown to be a more adequate parameter for selecting antioxidants than the widely used ECs0. This study revealed that guava leaf extracts comprise effective potential source of natural antioxidants.

  13. Antioxidant power of phytochemicals from Psidium guajava leaf

    Institute of Scientific and Technical Information of China (English)

    QIAN He (钱和); NIHORIMBERE Venant

    2004-01-01

    Dried ground leaves of Psidium guajava L. (guava) were extracted by water and aqueous ethyl alcohol 50% (1:10) ratio, and the total phenolic content in the extracts was determined spectrophotometrically according to Folin- Ciocalteu's phenol method and calculated as gallic acid equivalent (GAE). Remarkably high total phenolic content 575.3 (15.5 and 511.6(6.2 mg of GAE/g of dried weight material (for ethanol guava leaf extracts and water guava leaf extracts, respectively) were obtained. The antioxidant activity of lyophilized extracts was determined at ambient temperature by means of a 2,2-diphenyl-1-picrylhydryzyl (DPPH˙) colorimetry with detection scheme at 515 nm. The activity was evaluated by the decrease in absorbance as the result of DPPH˙ color change from purple to yellow. The higher the sample concentration used, the stronger was the free radical-scavenging effect. The results obtained showed that ascorbic acid was a substantially more powerful antioxidant than the extracts from guava leaf. On the other hand, the commercial guava leaf extracts and ethanol guava leaf extracts showed almost the same antioxidant power whereas water guava leaf extracts showed lower antioxidant activity. The parameter EC50 and the time needed to reach the steady state to EC50 concentration (TEC90) affected the antiradical capacity of the sample. The antioxidant efficiency (AE) has been shown to be a more adequate parameter for selecting antioxidants than the widely used EC50. This study revealed that guava leaf extracts comprise effective potential source of natural antioxidants.

  14. Are leaf chemistry signatures preserved at the canopy level?

    Energy Technology Data Exchange (ETDEWEB)

    Borel, C.C.; Gerstl, S.A.W.

    1994-05-01

    Imaging spectrometers have the potential to be very useful in remote sensing of canopy chemistry constituents such as nitrogen and lignin. In this study under the HIRIS project the question of how leaf chemical composition which is reflected in leaf spectral features in the reflectance and transmittance is affected by canopy architecture was investigated. Several plants were modeled with high fidelity and a radiosity model was used to compute the canopy spectral signature over the visible and near infrared. We found that chemical constituent specific signatures such as absorptions are preserved and in the case of low absorption are actually enhanced. For moderately dense canopies the amount of a constituent depends also on the total leaf area.

  15. In Azospirillum brasilense, mutations in flmA or flmB genes affect polar flagellum assembly, surface polysaccharides, and attachment to maize roots.

    Science.gov (United States)

    Rossi, Fernando Ariel; Medeot, Daniela Beatriz; Liaudat, Juan Pablo; Pistorio, Mariano; Jofré, Edgardo

    2016-09-01

    Azospirillum brasilense is a soil bacterium capable of promoting plant growth. Several surface components were previously reported to be involved in the attachment of A. brasilense to root plants. Among these components are the exopolysaccharide (EPS), lipopolysaccharide (LPS) and the polar flagellum. Flagellin from polar flagellum is glycosylated and it was suggested that genes involved in such a posttranslational modification are the same ones involved in the biosynthesis of sugars present in the O-antigen of the LPS. In this work, we report on the characterization of two homologs present in A. brasilense Cd, to the well characterized flagellin modification genes, flmA and flmB, from Aeromonas caviae. We show that mutations in either flmA or flmB genes of A. brasilense resulted in non-motile cells due to alterations in the polar flagellum assembly. Moreover, these mutations also affected the capability of A. brasilense cells to adsorb to maize roots and to produce LPS and EPS. By generating a mutant containing the polar flagellum affected in their rotation, we show the importance of the bacterial motility for the early colonization of maize roots.

  16. Harnessing Genetic Variation in Leaf Angle to Increase Productivity of Sorghum bicolor.

    Science.gov (United States)

    Truong, Sandra K; McCormick, Ryan F; Rooney, William L; Mullet, John E

    2015-11-01

    The efficiency with which a plant intercepts solar radiation is determined primarily by its architecture. Understanding the genetic regulation of plant architecture and how changes in architecture affect performance can be used to improve plant productivity. Leaf inclination angle, the angle at which a leaf emerges with respect to the stem, is a feature of plant architecture that influences how a plant canopy intercepts solar radiation. Here we identify extensive genetic variation for leaf inclination angle in the crop plant Sorghum bicolor, a C4 grass species used for the production of grain, forage, and bioenergy. Multiple genetic loci that regulate leaf inclination angle were identified in recombinant inbred line populations of grain and bioenergy sorghum. Alleles of sorghum dwarf-3, a gene encoding a P-glycoprotein involved in polar auxin transport, are shown to change leaf inclination angle by up to 34° (0.59 rad). The impact of heritable variation in leaf inclination angle on light interception in sorghum canopies was assessed using functional-structural plant models and field experiments. Smaller leaf inclination angles caused solar radiation to penetrate deeper into the canopy, and the resulting redistribution of light is predicted to increase the biomass yield potential of bioenergy sorghum by at least 3%. These results show that sorghum leaf angle is a heritable trait regulated by multiple loci and that genetic variation in leaf angle can be used to modify plant architecture to improve sorghum crop performance.

  17. Surface orientation affects the direction of cone growth by Leptolyngbya sp. strain C1, a likely architect of coniform structures Octopus Spring (Yellowstone National Park).

    Science.gov (United States)

    Reyes, Kristina; Gonzalez, Nicolas I; Stewart, Joshua; Ospino, Frank; Nguyen, Dickie; Cho, David T; Ghahremani, Nahal; Spear, John R; Johnson, Hope A

    2013-02-01

    Laminated, microbially produced stromatolites within the rock record provide some of the earliest evidence for life on Earth. The chemical, physical, and biological factors that lead to the initiation of these organosedimentary structures and shape their morphology are unclear. Modern coniform structures with morphological features similar to stromatolites are found on the surface of cyanobacterial/microbial mats. They display a vertical element of growth, can have lamination, can be lithified, and observably grow with time. To begin to understand the microbial processes and interactions required for cone formation, we determined the phylogenetic composition of the microbial community of a coniform structure from a cyanobacterial mat at Octopus Spring, Yellowstone National Park, and reconstituted coniform structures in vitro. The 16S rRNA clone library from the coniform structure was dominated by Leptolyngbya sp. Other cyanobacteria and heterotrophic bacteria were present in much lower abundance. The same Leptolyngbya sp. identified in the clone library was also enriched in the laboratory and could produce cones in vitro. When coniform structures were cultivated in the laboratory, the initial incubation conditions were found to influence coniform morphology. In addition, both the angle of illumination and the orientation of the surface affected the angle of cone formation demonstrating how external factors can influence coniform, and likely, stromatolite morphology.

  18. The influence of leaf anatomy on the internal light environment and photosynthetic electron transport rate: exploration with a new leaf ray tracing model.

    Science.gov (United States)

    Xiao, Yi; Tholen, Danny; Zhu, Xin-Guang

    2016-11-01

    Leaf photosynthesis is determined by biochemical properties and anatomical features. Here we developed a three-dimensional leaf model that can be used to evaluate the internal light environment of a leaf and its implications for whole-leaf electron transport rates (J). This model includes (i) the basic components of a leaf, such as the epidermis, palisade and spongy tissues, as well as the physical dimensions and arrangements of cell walls, vacuoles and chloroplasts; and (ii) an efficient forward ray-tracing algorithm, predicting the internal light environment for light of wavelengths between 400 and 2500nm. We studied the influence of leaf anatomy and ambient light on internal light conditions and J The results show that (i) different chloroplasts can experience drastically different light conditions, even when they are located at the same distance from the leaf surface; (ii) bundle sheath extensions, which are strips of parenchyma, collenchyma or sclerenchyma cells connecting the vascular bundles with the epidermis, can influence photosynthetic light-use efficiency of leaves; and (iii) chloroplast positioning can also influence the light-use efficiency of leaves. Mechanisms underlying leaf internal light heterogeneity and implications of the heterogeneity for photoprotection and for the convexity of the light response curves are discussed.

  19. Leaf hydraulic conductance for a tank bromeliad: axial and radial pathways for moving and conserving water.

    Science.gov (United States)

    North, Gretchen B; Lynch, Frank H; Maharaj, Franklin D R; Phillips, Carly A; Woodside, Walter T

    2013-01-01

    Epiphytic plants in the Bromeliaceae known as tank bromeliads essentially lack stems and absorptive roots and instead take up water from reservoirs formed by their overlapping leaf bases. For such plants, leaf hydraulic conductance is plant hydraulic conductance. Their simple strap-shaped leaves and parallel venation make them suitable for modeling leaf hydraulic conductance based on vasculature and other anatomical and morphological traits. Plants of the tank bromeliad Guzmania lingulata were investigated in a lowland tropical forest in Costa Rica and a shaded glasshouse in Los Angeles, CA, USA. Stomatal conductance to water vapor and leaf anatomical variables related to hydraulic conductance were measured for both groups. Tracheid diameters and numbers of vascular bundles (veins) were used with the Hagen-Poiseuille equation to calculate axial hydraulic conductance. Measurements of leaf hydraulic conductance using the evaporative flux method were also made for glasshouse plants. Values for axial conductance and leaf hydraulic conductance were used in a model based on leaky cable theory to estimate the conductance of the radial pathway from the vein to the leaf surface and to assess the relative contributions of both axial and radial pathways. In keeping with low stomatal conductance, low stomatal density, low vein density, and narrow tracheid diameters, leaf hydraulic conductance for G. lingulata was quite low in comparison with most other angiosperms. Using the predicted axial conductance in the leaky cable model, the radial resistance across the leaf mesophyll was predicted to predominate; lower, more realistic values of axial conductance resulted in predicted radial resistances that were closer to axial resistance in their impact on total leaf resistance. Tracer dyes suggested that water uptake through the tank region of the leaf was not limiting. Both dye movement and the leaky cable model indicated that the leaf blade of G. lingulata was structurally and

  20. Predicting green leaf proportion in ungrazed kleingrass (Panicum coloratum L.) in the semiarid Pampas Region of Argentina

    OpenAIRE

    Carlos M Ferri; M. Lia Molas

    2013-01-01

    Green leaf proportion is an important factor affecting nutritive value, ingestive behavior and forage intake. Determination of green leaf proportion by hand separation of plant samples is time consuming and expensive. The aim of this work was to establish whether a stable relationship exists between the proportion of green leaf blade and total mass of harvestable forage in ungrazed kleingrass (Panicum coloratum L.) cv. Verde. The study was carried out during four consecutive growing seasons i...

  1. Groundwater and surface-water interaction, water quality, and processes affecting loads of dissolved solids, selenium, and uranium in Fountain Creek near Pueblo, Colorado, 2012–2014

    Science.gov (United States)

    Arnold, L. Rick; Ortiz, Roderick F.; Brown, Christopher R.; Watts, Kenneth R.

    2016-11-28

    In 2012, the U.S. Geological Survey, in cooperation with the Arkansas River Basin Regional Resource Planning Group, initiated a study of groundwater and surface-water interaction, water quality, and loading of dissolved solids, selenium, and uranium to Fountain Creek near Pueblo, Colorado, to improve understanding of sources and processes affecting loading of these constituents to streams in the Arkansas River Basin. Fourteen monitoring wells were installed in a series of three transects across Fountain Creek near Pueblo, and temporary streamgages were established at each transect to facilitate data collection for the study. Groundwater and surface-water interaction was characterized by using hydrogeologic mapping, groundwater and stream-surface levels, groundwater and stream temperatures, vertical hydraulic-head gradients and ratios of oxygen and hydrogen isotopes in the hyporheic zone, and streamflow mass-balance measurements. Water quality was characterized by collecting periodic samples from groundwater, surface water, and the hyporheic zone for analysis of dissolved solids, selenium, uranium, and other selected constituents and by evaluating the oxidation-reduction condition for each groundwater sample under different hydrologic conditions throughout the study period. Groundwater loads to Fountain Creek and in-stream loads were computed for the study area, and processes affecting loads of dissolved solids, selenium, and uranium were evaluated on the basis of geology, geochemical conditions, land and water use, and evapoconcentration.During the study period, the groundwater-flow system generally contributed flow to Fountain Creek and its hyporheic zone (as a single system) except for the reach between the north and middle transects. However, the direction of flow between the stream, the hyporheic zone, and the near-stream aquifer was variable in response to streamflow and stage. During periods of low streamflow, Fountain Creek generally gained flow from

  2. Is handwriting performance affected by the writing surface? Comparing preschoolers’, second graders’ and adults’ writing performance on a tablet versus paper

    Directory of Open Access Journals (Sweden)

    Sabrina Gerth

    2016-09-01

    Full Text Available Due to their multifunctionality, tablets offer tremendous advantages for research on handwriting dynamics or for interactive use of learning apps in schools. Further, the widespread use of tablet computers has had a great impact on handwriting in the current generation. But, is it advisable to teach how to write and to assess handwriting in pre- and primary schoolchildren on tablets rather than on paper? Since handwriting is not automatized before the age of ten years, children’s handwriting movements require graphomotor and visual feedback as well as permanent control of movement execution during handwriting. Modifications in writing conditions, for instance the smoother writing surface of a tablet, might influence handwriting performance in general, and in particular those of non-automatized beginning writers.In order to investigate how handwriting performance is affected by a difference in friction of the writing surface, we recruited three groups with varying levels of handwriting automaticity: 25 preschoolers, 27 second graders and 25 adults. We administered three tasks measuring graphomotor abilities, visuomotor abilities and handwriting performance (only second graders and adults. We evaluated two aspects of handwriting performance: the handwriting quality with a visual score and the handwriting dynamics using online handwriting measures (e.g. writing duration, writing velocity, strokes and number of inversions in velocity (NIV. In particular, NIVs which describe the number of velocity peaks during handwriting, are directly related to the level of handwriting automaticity.In general, we found differences between writing on paper compared to the tablet. These differences were partly task-dependent. The comparison between tablet and paper revealed a faster writing velocity for all groups and all tasks on the tablet which indicates that all participants – even the experienced writers – were influenced by the lower friction of the

  3. Is Handwriting Performance Affected by the Writing Surface? Comparing Preschoolers', Second Graders', and Adults' Writing Performance on a Tablet vs. Paper

    Science.gov (United States)

    Gerth, Sabrina; Klassert, Annegret; Dolk, Thomas; Fliesser, Michael; Fischer, Martin H.; Nottbusch, Guido; Festman, Julia

    2016-01-01

    Due to their multifunctionality, tablets offer tremendous advantages for research on handwriting dynamics or for interactive use of learning apps in schools. Further, the widespread use of tablet computers has had a great impact on handwriting in the current generation. But, is it advisable to teach how to write and to assess handwriting in pre- and primary schoolchildren on tablets rather than on paper? Since handwriting is not automatized before the age of 10 years, children's handwriting movements require graphomotor and visual feedback as well as permanent control of movement execution during handwriting. Modifications in writing conditions, for instance the smoother writing surface of a tablet, might influence handwriting performance in general and in particular those of non-automatized beginning writers. In order to investigate how handwriting performance is affected by a difference in friction of the writing surface, we recruited three groups with varying levels of handwriting automaticity: 25 preschoolers, 27 second graders, and 25 adults. We administered three tasks measuring graphomotor abilities, visuomotor abilities, and handwriting performance (only second graders and adults). We evaluated two aspects of handwriting performance: the handwriting quality with a visual score and the handwriting dynamics using online handwriting measures [e.g., writing duration, writing velocity, strokes and number of inversions in velocity (NIV)]. In particular, NIVs which describe the number of velocity peaks during handwriting are directly related to the level of handwriting automaticity. In general, we found differences between writing on paper compared to the tablet. These differences were partly task-dependent. The comparison between tablet and paper revealed a faster writing velocity for all groups and all tasks on the tablet which indicates that all participants—even the experienced writers—were influenced by the lower friction of the tablet surface. Our

  4. 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

  5. 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.

  6. RELATIONSHIP BETWEEN MANGOSTEEN LEAF NITROGEN CONTENTS AND LEAF SPAD VALUES

    Directory of Open Access Journals (Sweden)

    Eko Setiawan

    2014-03-01

    Full Text Available We investigated nitrogen contents on mangosteen leaf and related on leaf SPAD value. The experiment was conducted using mangosteen trees grown in commercial orchard in Bogor, Indonesia during May to October 2010. Mangosteen trees of 3 different ages, young (20-year-old, middle-aged (35-year-old, and old (50-year-old trees, each of five trees, were selected for study, and the canopy of each tree was divided into 9 sectors based on height (bottom, middle, top and width (inner, center, outer. SPAD values had a negative correlation with leaf N content in all ages and could be explained by regressionl equations N level (% DW = -0.0099 × SPAD + 2.2366; R² = 0.91; N level (% DW = -0.0177 × SPAD + 2.8001; R² = 0.67; and N level (% DW = -0.0187 × SPAD + 2.7785; R² = 0.45 in young, middle-aged and old trees, respectively. It is suggested that the SPAD value determined by a portable chlorophyll meter can be used to obtain a quick estimation of mangosteen leaf N status. Keywords: age, fruiting position, Garcinia mangostana L., nitrogen, SPAD

  7. Characteristics of leaf areas of plantations in semiarid hills and gully loess regions

    Institute of Scientific and Technical Information of China (English)

    Jing YIN; Fan HE; Guoyu QIU; Kangning HE; Jinghui TIAN; Weiqiang ZHANG; Yujiu XIONG; Shaohua ZHAO; Jianxin LIU

    2009-01-01

    The objectives of our study were to explore the relationship of leaf area and stand density and to find a convenient way to measure stand leaf areas. During the 2004 growing season, from May to October, we used direct and indirect methods to measure the seasonal variation of the leaf areas of tree and shrub species. The trees were from Robinia pseudoacacia stands of four densities (3333 plants/hm2, 1666 plants/hm2, 1111 plants/hm2, and 833 plants/hm2) and Platycladus orientalis stands of three densities (3333 plants/hm2, 1666 plants/hm2, and 1111 plants/hm2). The shrub species were Caragana korshinskii, Hippophae rhamnoides, and Amorpha fruticosa. Based on our survey data, empirical formulas for calculating leaf area were obtained by correlating leaf fresh weight, diameter of base branches, and leaf areas. Our results show the following: 1) in September, the leaf area and leaf area index (LAI) of trees (R. pseudoacacia and P orientalis) reached their maximum values, with LAI peak values of 10.5 and 3.2, respectively. In August, the leaf area and LAI of shrubs (C. korshinskii, H. rhamnoides, and A. fruticosa) reached their maximum values, with LAI peak values of 1.195, 1.123, and 1.882, respectively. 2) There is a statistically significant power relation between leaf area and leaf fresh weight for R. pseudoacacia. There are significant linear relationships between leaf area and leaf fresh weight for P. orientalis, C. korshinskii, H. rhamnoides, and A. fruticosa. Moreover, there is also a significant power relation between leaf area and diameter of base branches for C. korshinskii. There are significant linear relations between leaf area and diameter of base branches of H. rhamnoides and A. fruticosa. 3) In the hills and gully regions of the Loess Plateau, the LAIs of R. pseudoacacia stand at different densities converged after the planted stands entered their fast growth stage. Their LAI do not seem to be affected by its initial and current density. The same is true

  8. Leaf out times of temperate woody plants are related to phylogeny, deciduousness, growth habit and wood anatomy.

    Science.gov (United States)

    Panchen, Zoe A; Primack, Richard B; Nordt, Birgit; Ellwood, Elizabeth R; Stevens, Albert-Dieter; Renner, Susanne S; Willis, Charles G; Fahey, Robert; Whittemore, Alan; Du, Yanjun; Davis, Charles C

    2014-09-01

    Leaf out phenology affects a wide variety of ecosystem processes and ecological interactions and will take on added significance as leaf out times increasingly shift in response to warming temperatures associated with climate change. There is, however, relatively little information available on the factors affecting species differences in leaf out phenology. An international team of researchers from eight Northern Hemisphere temperate botanical gardens recorded leaf out dates of c. 1600 woody species in 2011 and 2012. Leaf out dates in woody species differed by as much as 3 months at a single site and exhibited strong phylogenetic and anatomical relationships. On average, angiosperms leafed out earlier than gymnosperms, deciduous species earlier than evergreen species, shrubs earlier than trees, diffuse and semi-ring porous species earlier than ring porous species, and species with smaller diameter xylem vessels earlier than species with larger diameter vessels. The order of species leaf out was generally consistent between years and among sites. As species distribution and abundance shift due to climate change, interspecific differences in leaf out phenology may affect ecosystem processes such as carbon, water, and nutrient cycling. Our open access leaf out data provide a critical framework for monitoring and modelling such changes going forward.

  9. Morpho-anatomical structure of the leaf apparatus of spring barley under the influence of herbicide and plant growth regulators

    Directory of Open Access Journals (Sweden)

    Vitaliy P. Karpenko

    2012-03-01

    Full Text Available It has been found that the number of epidermal cells of spring barley leaf apparatus on the surface unit of the leaf decreases while their size increases under the application of herbicide «Calibre 75» at the rates of 30, 40, 50, 60 and 70 g/ha in mixtures with «Agat - 25K» which is consistent with the formation of anatomic structure of the leaf apparatus belonging to mesomorphic type.

  10. Influence of Leaf Area Index Prescriptions on Simulations of Heat, Moisture, and Carbon Fluxes

    Science.gov (United States)

    Kala, Jatin; Decker, Mark; Exbrayat, Jean-Francois; Pitman, Andy J.; Carouge, Claire; Evans, Jason P.; Abramowitz, Gab; Mocko, David

    2013-01-01

    Leaf-area index (LAI), the total one-sided surface area of leaf per ground surface area, is a key component of land surface models. We investigate the influence of differing, plausible LAI prescriptions on heat, moisture, and carbon fluxes simulated by the Community Atmosphere Biosphere Land Exchange (CABLEv1.4b) model over the Australian continent. A 15-member ensemble monthly LAI data-set is generated using the MODIS LAI product and gridded observations of temperature and precipitation. Offline simulations lasting 29 years (1980-2008) are carried out at 25 km resolution with the composite monthly means from the MODIS LAI product (control simulation) and compared with simulations using each of the 15-member ensemble monthly-varying LAI data-sets generated. The imposed changes in LAI did not strongly influence the sensible and latent fluxes but the carbon fluxes were more strongly affected. Croplands showed the largest sensitivity in gross primary production with differences ranging from -90 to 60 %. PFTs with high absolute LAI and low inter-annual variability, such as evergreen broadleaf trees, showed the least response to the different LAI prescriptions, whilst those with lower absolute LAI and higher inter-annual variability, such as croplands, were more sensitive. We show that reliance on a single LAI prescription may not accurately reflect the uncertainty in the simulation of the terrestrial carbon fluxes, especially for PFTs with high inter-annual variability. Our study highlights that the accurate representation of LAI in land surface models is key to the simulation of the terrestrial carbon cycle. Hence this will become critical in quantifying the uncertainty in future changes in primary production.

  11. 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.

  12. Remote sensing of LAI, chlorophyll and leaf nitrogen pools of crop- and grasslands in five European landscapes

    KAUST Repository

    Boegh, E.

    2013-10-07

    Leaf nitrogen and leaf surface area influence the exchange of gases between terrestrial ecosystems and the atmosphere, and play a significant role in the global cycles of carbon, nitrogen and water. The purpose of this study is to use field-based and satellite remote-sensing-based methods to assess leaf nitrogen pools in five diverse European agricultural landscapes located in Denmark, Scotland (United Kingdom), Poland, the Netherlands and Italy. REGFLEC (REGularized canopy reFLECtance) is an advanced image-based inverse canopy radiative transfer modelling system which has shown proficiency for regional mapping of leaf area index (LAI) and leaf chlorophyll (CHLl) using remote sensing data. In this study, high spatial resolution (10-20 m) remote sensing images acquired from the multispectral sensors aboard the SPOT (Satellite For Observation of Earth) satellites were used to assess the capability of REGFLEC for mapping spatial variations in LAI, CHLland the relation to leaf nitrogen (Nl) data in five diverse European agricultural landscapes. REGFLEC is based on physical laws and includes an automatic model parameterization scheme which makes the tool independent of field data for model calibration. In this study, REGFLEC performance was evaluated using LAI measurements and non-destructive measurements (using a SPAD meter) of leaf-scale CHLl and Nl concentrations in 93 fields representing crop- and grasslands of the five landscapes. Furthermore, empirical relationships between field measurements (LAI, CHLl and Nl and five spectral vegetation indices (the Normalized Difference Vegetation Index, the Simple Ratio, the Enhanced Vegetation Index-2, the Green Normalized Difference Vegetation Index, and the green chlorophyll index) were used to assess field data coherence and to serve as a comparison basis for assessing REGFLEC model performance. The field measurements showed strong vertical CHLl gradient profiles in 26% of fields which affected REGFLEC performance as well

  13. Leaf surface wettability of major plant species for urban greening in Xi'an and related affecting factors%西安市常见绿化植物叶片润湿性能及其影响因素

    Institute of Scientific and Technical Information of China (English)

    王会霞; 石辉; 李秧秧

    2010-01-01

    利用接触角测定仪测定了西安市21种常见绿化植物叶片表面的接触角,探讨了叶片表面特性如蜡质、绒毛、气孔对接触角的影响.结果表明,植物叶片正背面、物种间的接触角差异均显著,叶片正面和背面接触角大小在40°~140°.接触角大小与变异系数呈负相关,可能由于接触角小的润湿叶片在不同的生境和位置下,受到环境条件的影响较大而出现大的变异;接触角较大的非润湿性叶片,环境物质持留时间较短,对叶片形态和组成影响较小,因而出现小的变异.植物叶片表面的接触角随蜡质含量的升高而增大.表皮蜡质去除后大部分叶片接触角明显降低,尤其是疏水性较强的银杏(Ginkgo biloba)、月季(Rosa chinensis)和紫叶小檗(Berberis thunbergii).女贞(Ligustrum lucidum)正背面、加杨(Populus canadensis)背面等亲水型的叶片蜡质去除后接触角反而增大.叶片绒毛的多少及其形态、分布方式对接触角具有重要的影响,不同的作用方式表现出润湿和不润湿的特征,人为将其去除可以增加叶片的润湿性.背面气孔密度与气孔长度、保卫细胞长度呈负相关;接触角则与气孔密度呈负相关,与气孔长度呈正相关.

  14. LEAF: A Microcomputer Program for Constructing the Tukey Stem and Leaf Graph.

    Science.gov (United States)

    Pascale, Pietro J.; Smith, Joseph

    1986-01-01

    This paper presents a BASIC microcomputer program that constructs the Tukey (1977) stem and leaf graph. Options within the LEAF program include a modified stem and leaf where the stem is split and a parallel stem and leaf graph where two separate sets of data are displayed from a common stem. (Author)

  15. Changes of Leaf Morphological, Anatomical Structure and Carbon Isotope Ratio with the Height of the Wangtian Tree (Parashorea chinensis) in Xishuangbanna, China

    Institute of Scientific and Technical Information of China (English)

    Chun-Xia He; Ji-Yue Li; Ping Zhou; Ming Guo; Quan-Shui Zheng

    2008-01-01

    Leaf morphological and anatomical structure and carbon isotope ratio (δ13C) change with increasing tree height. To determine how tree height affects leaf characteristics, we measured the leaf area, specific leaf mass (ratio of leaf mass to leaf area [LMA]), thickness of the total leaf, cuticle, epidermis, palisade and sponge mesophyll, stomata traits and δ13C at different heights of Parashorea chinensis with methods of light and scanning electron microscopy (SEM) and isotope-ratio mass spectrometry. The correlation and stepwise regression between tree height and leaf structure traits were carried out with SPSS software. The results showed that leaf structures and δ13C differed significantly along the tree height gradient. The leaf area, thickness of sponge mesophyll and size of stomata decreased with increasing height, whereas the thickness of lamina, palisade mesophyll, epidermis, and cuticle, ratios of palisade to spongy thickness, density of stomata and vascular bundles, LMA and δ13C increased with tree height. Tree height showed a significant relationship with all leaf Indices and the most significant relationship was with epidermis thickness, leaf area, cuticle thickness, δ13C. The δ13C value showed a significantly positive relationship with LMA (R = 0.934). Our results supported the hypothesis that the leaf structures exhibited more xeromorphic characteristics with the increasing gradient of tree height.

  16. Changes of leaf morphological, anatomical structure and carbon isotope ratio with the height of the Wangtian tree (Parashorea chinensis) in Xishuangbanna, China.

    Science.gov (United States)

    He, Chun-Xia; Li, Ji-Yue; Zhou, Ping; Guo, Ming; Zheng, Quan-Shui

    2008-02-01

    Leaf morphological and anatomical structure and carbon isotope ratio (delta13C) change with increasing tree height. To determine how tree height affects leaf characteristics, we measured the leaf area, specific leaf mass (ratio of leaf mass to leaf area [LMA]), thickness of the total leaf, cuticle, epidermis, palisade and sponge mesophyll, stomata traits and delta13C at different heights of Parashorea chinensis with methods of light and scanning electron microscopy (SEM) and isotope-ratio mass spectrometry. The correlation and stepwise regression between tree height and leaf structure traits were carried out with SPSS software. The results showed that leaf structures and delta13C differed significantly along the tree height gradient. The leaf area, thickness of sponge mesophyll and size of stomata decreased with increasing height, whereas the thickness of lamina, palisade mesophyll, epidermis, and cuticle, ratios of palisade to spongy thickness, density of stomata and vascular bundles, LMA and delta13C increased with tree height. Tree height showed a significant relationship with all leaf indices and the most significant relationship was with epidermis thickness, leaf area, cuticle thickness, delta13C. The delta13C value showed a significantly positive relationship with LMA (R = 0.934). Our results supported the hypothesis that the leaf structures exhibited more xeromorphic characteristics with the increasing gradient of tree height.

  17. Interrelationships between leaf heat conductivity and tissue structures of different varieties of Populus tomentosa Carr.

    Institute of Scientific and Technical Information of China (English)

    WANG Min; ZHANG Wen-jie; XIAO Jian; ZHANG Zhi-yi; LIU Jing

    2008-01-01

    Plant heat conductivity largely depends on tissue structure. Different structures lead to different heat conductivity. As well, water transfer also plays a very important role in heat transfer in plants. We have studied leaf heat conductivity and tissue structure of 3- and 30-year-old Populus tomentosa Carr. trees using mildred thermal imaging, steady state heat conductivity surveys and paraffin section and investigated the relationship between leaf heat conductivity, tissue structure and water content of leaves. The results show that the temperature on leaf surfaces among the various varieties of trees was almost the same. Leaf heat conductivity, temperature and water content of leaves are positively correlated. The thicker the leaf tissue structures, the larger the heat resistance. That is, the tighter the cells and the smaller the interspaces, the smaller the heat conductivity, which is not conducive for heat transfer.

  18. 7 CFR 29.3035 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.3035 Section 29.3035 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Leaf structure. The cell development of a leaf as indicated by its porosity or solidity. (See...

  19. 7 CFR 29.3527 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.3527 Section 29.3527 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 95) § 29.3527 Leaf structure. The cell development of a leaf as indicated by its porosity....

  20. 7 CFR 29.6023 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.6023 Section 29.6023 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6023 Leaf structure. The cell development of a leaf as indicated by...

  1. 7 CFR 29.1030 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.1030 Section 29.1030 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 92) § 29.1030 Leaf structure. The cell development of a leaf as indicated by its porosity....

  2. 7 CFR 29.2529 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.2529 Section 29.2529 Agriculture...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2529 Leaf scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed tobacco and consists of loose and tangled whole...

  3. 7 CFR 29.6022 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.6022 Section 29.6022 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6022 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap...

  4. 7 CFR 29.3526 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.3526 Section 29.3526 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 95) § 29.3526 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results from...

  5. 7 CFR 29.3034 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.3034 Section 29.3034 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Leaf scrap. A by-product of unstemmed tobacco. Leaf scrap results from handling unstemmed tobacco...

  6. Comparison of half and full-leaf shape feature extraction for leaf classification

    Science.gov (United States)

    Sainin, Mohd Shamrie; Ahmad, Faudziah; Alfred, Rayner

    2016-08-01

    Shape is the main information for leaf feature that most of the current literatures in leaf identification utilize the whole leaf for feature extraction and to be used in the leaf identification process. In this paper, study of half-leaf features extraction for leaf identification is carried out and the results are compared with the results obtained from the leaf identification based on a full-leaf features extraction. Identification and classification is based on shape features that are represented as cosines and sinus angles. Six single classifiers obtained from WEKA and seven ensemble methods are used to compare their performance accuracies over this data. The classifiers were trained using 65 leaves in order to classify 5 different species of preliminary collection of Malaysian medicinal plants. The result shows that half-leaf features extraction can be used for leaf identification without decreasing the predictive accuracy.

  7. 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.

  8. Overexpression of a NAC transcription factor delays leaf senescence and increases grain nitrogen concentration in wheat.

    Science.gov (United States)

    Zhao, D; Derkx, A P; Liu, D-C; Buchner, P; Hawkesford, M J

    2015-07-01

    Increasing the duration of leaf photosynthesis during grain filling using slow-senescing functional stay-green phenotypes is a possible route for increasing grain yields in wheat (Triticum aestivum L.). However, delayed senescence may negatively affect nutrient remobilisation and hence reduce grain protein concentrations and grain quality. A novel NAC1-type transcription factor (hereafter TaNAC-S) was identified in wheat, with gene expression located primarily in leaf/sheath tissues, which decreased during post-anthesis leaf senescence. Expression of TaNAC-S in the second leaf correlated with delayed senescence in two doubled-haploid lines of an Avalon × Cadenza population (lines 112 and 181), which were distinct for leaf senescence. Transgenic wheat plants overexpressing TaNAC-S resulted in delayed leaf senescence (stay-green phenotype). Grain yield, aboveground biomass, harvest index and total grain N content were unaffected, but NAC over-expressing lines had higher grain N concentrations at similar grain yields compared to non-transgenic controls. These results indicate that TaNAC-S is a negative regulator of leaf senescence, and that delayed leaf senescence may lead not only to increased grain yields but also to increased grain protein concentrations.

  9. Modeling development and quantitative trait mapping reveal independent genetic modules for leaf size and shape.

    Science.gov (United States)

    Baker, Robert L; Leong, Wen Fung; Brock, Marcus T; Markelz, R J Cody; Covington, Michael F; Devisetty, Upendra K; Edwards, Christine E; Maloof, Julin; Welch, Stephen; Weinig, Cynthia

    2015-10-01

    Improved predictions of fitness and yield may be obtained by characterizing the genetic controls and environmental dependencies of organismal ontogeny. Elucidating the shape of growth curves may reveal novel genetic controls that single-time-point (STP) analyses do not because, in theory, infinite numbers of growth curves can result in the same final measurement. We measured leaf lengths and widths in Brassica rapa recombinant inbred lines (RILs) throughout ontogeny. We modeled leaf growth and allometry as function valued traits (FVT), and examined genetic correlations between these traits and aspects of phenology, physiology, circadian rhythms and fitness. We used RNA-seq to construct a SNP linkage map and mapped trait quantitative trait loci (QTL). We found genetic trade-offs between leaf size and growth rate FVT and uncovered differences in genotypic and QTL correlations involving FVT vs STPs. We identified leaf shape (allometry) as a genetic module independent of length and width and identified selection on FVT parameters of development. Leaf shape is associated with venation features that affect desiccation resistance. The genetic independence of leaf shape from other leaf traits may therefore enable crop optimization in leaf shape without negative effects on traits such as size, growth rate, duration or gas exchange.

  10. Weak leaf photosynthesis and nutrient content relationships from tropical vegetation

    Science.gov (United States)

    Domingues, T. F.; Ishida, F. Y.; Feldpaush, T.; Saiz, G.; Grace, J.; Meir, P.; Lloyd, J.

    2015-12-01

    Evergreen rain forests and savannas are the two major vegetations of tropical land ecosystems, in terms of land area, biomass, biodiversity, biogeochemical cycles and rates of land use change. Mechanistically understanding ecosystem functioning on such ecosystems is still far from complete, but important for generation of future vegetation scenarios in response to global changes. Leaf photosynthetic rates is a key processes usually represented on land surface-atmosphere models, although data from tropical ecosystems is scarce, considering the high biodiversity they contain. As a shortcut, models usually recur to relationships between leaf nutrient concentration and photosynthetic rates. Such strategy is convenient, given the possibility of global datasets on leave nutrients derived from hyperspectral remote sensing data. Given the importance of Nitrogen on enzyme composition, this nutrient is usually used to infer photosynthetic capacity of leaves. Our experience, based on individual measurements on 1809 individual leaves from 428 species of trees and shrubs naturally occurring on tropical forests and savannas from South America, Africa and Australia, indicates that the relationship between leaf nitrogen and its assimilation capacity is weak. Therefore, leaf Nitrogen alone is a poor predictor of photosynthetic rates of tropical vegetation. Phosphorus concentrations from tropical soils are usually low and is often implied that this nutrient limits primary productivity of tropical vegetation. Still, phosphorus (or other nutrients) did not exerted large influence over photosynthetic capacity, although potassium influenced vegetation structure and function. Such results draw attention to the risks of applying universal nitrogen-photosynthesis relationships on biogeochemical models. Moreover, our data suggests that affiliation of plant species within phylogenetic hierarchy is an important aspect in understanding leaf trait variation. The lack of a strong single

  11. Leafing patterns and leaf traits of four evergreen shrubs in the Patagonian Monte, Argentina

    Science.gov (United States)

    Campanella, María Victoria; Bertiller, Mónica B.

    2009-11-01

    We assessed leafing patterns (rate, timing, and duration of leafing) and leaf traits (leaf longevity, leaf mass per area and leaf-chemistry) in four co-occurring evergreen shrubs of the genus Larrea and Chuquiraga (each having two species) in the arid Patagonian Monte of Argentina. We asked whether species with leaves well-defended against water shortage (high LMA, leaf longevity, and lignin concentration, and low N concentration) have lower leaf production, duration of the leafing period, and inter-annual variation of leafing than species with the opposite traits. We observed two distinctive leafing patterns each related to one genus. Chuquiraga species produced new leaves concentrated in a massive short leafing event (5-48 days) while new leaves of Larrea species emerged gradually (128-258 days). Observed leafing patterns were consistent with simultaneous and successive leafing types previously described for woody plants. The peak of leaf production occurred earlier in Chuquiraga species (mid September) than in Larrea species (mid October-late November). Moreover, Chuquiraga species displayed leaves with the longest leaf lifespan, while leaves of Larrea species had the lowest LMA and the highest N and soluble phenolics concentrations. We also observed that only the leaf production of Larrea species increased in humid years. We concluded that co-occurring evergreen species in the Patagonian Monte displayed different leafing patterns, which were associated with some relevant leaf traits acting as plant defenses against water stress and herbivores. Differences in leafing patterns could provide evidence of ecological differentiation among coexisting species of the same life form.

  12. Decreased toxicity of Bacillus thuringiensis subsp. israelensis to mosquito larvae after contact with leaf litter.

    Science.gov (United States)

    Tetreau, Guillaume; Stalinski, Renaud; Kersusan, Dylann; Veyrenc, Sylvie; David, Jean-Philippe; Reynaud, Stéphane; Després, Laurence

    2012-08-01

    Bacillus thuringiensis subsp. israelensis is a bacterium producing crystals containing Cry and Cyt proteins, which are toxic for mosquito larvae. Nothing is known about the interaction between crystal toxins and decaying leaf litter, which is a major component of several mosquito breeding sites and represents an important food source. In the present work, we investigated the behavior of B. thuringiensis subsp. israelensis toxic crystals sprayed on leaf litter. In the presence of leaf litter, a 60% decrease in the amount of Cyt toxin detectable by immunology (enzyme-linked immunosorbent assays [ELISAs]) was observed, while the respective proportions of Cry toxins were not affected. The toxicity of Cry toxins toward Aedes aegypti larvae was not affected by leaf litter, while the synergistic effect of Cyt toxins on all B. thuringiensis subsp. israelensis Cry toxins was decreased by about 20% when mixed with leaf litter. The toxicity of two commercial B. thuringiensis subsp. israelensis strains (VectoBac WG and VectoBac 12AS) and a laboratory-produced B. thuringiensis subsp. israelensis strain decreased by about 70% when mixed with leaf litter. Taken together, these results suggest that Cyt toxins interact with leaf litter, resulting in a decreased toxicity of B. thuringiensis subsp. israelensis in litter-rich environments and thereby dramatically reducing the efficiency of mosquitocidal treatments.

  13. LEAF MICROMOPHOMETRY OF PALICOUREA RIGIDA KUNTH. (RUBIACEAE FROM BRAZILIAN CERRADO AND CAMPO RUPESTRE ENVIRONMENTS

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    Manuel Losada Gavilanes

    2016-06-01

    Full Text Available The objective of this work was to evaluate qualitative and quantitative leaf anatomical traits of Palicourea rigida Kunth. (Rubiaceae species occurring in the Brazilian Cerrado and Campo Rupestre ecosystems. Anatomical analysis was performed in fresh or fixed leaves processed with usual plant microtechnique. Leaves showed uniseriate epidermis in petiole and leaf blade which contains uniseriate nonglandular tricomes (tector type occurring only over the vascular bundles. Likewise, paracytic stomata were found only in abaxial side of the leaf surface. The mesophyll contains uniseriate palisade parenchyma and multiseriate spongy parenchyma (nine layers which showed cells with different morphology and size. Crystal idoblasts of different types were observed in both the petiole and leaf blade. Collateral vascular bundles were found both in the petiole and leaf blade. Leaf venation type was pinnate, campylodromous or brochydodromous. The micromorphometric analysis showed significant differences from plants of different environments for all leaf characteristics and Cerrado plants showed higher means for all evaluated traits. Therefore, the influence of environments may had modulated morphological responses in P. rigida, since no difference was found in the type or distribution of leaf tissues in Cerrado or Campo Rupestre.

  14. Plant structure predicts leaf litter capture in the tropical montane bromeliad Tillandsia turneri

    Directory of Open Access Journals (Sweden)

    F. Ospina-Bautista

    Full Text Available Abstract Leaves intercepted by bromeliads become an important energy and matter resource for invertebrate communities, bacteria, fungi, and the plant itself. The relationship between bromeliad structure, defined as its size and complexity, and accumulated leaf litter was studied in 55 bromeliads of Tillandsia turneri through multiple regression and the Akaike information criterion. Leaf litter accumulation in bromeliads was best explained by size and complexity variables such as plant cover, sheath length, and leaf number. In conclusion, plant structure determines the amount of litter that enters bromeliads, and changes in its structure could affect important processes within ecosystem functioning or species richness.

  15. Delivering high-resolution landmarks using inkjet micropatterning for spatial monitoring of leaf expansion

    Directory of Open Access Journals (Sweden)

    Cronk Quentin CB

    2011-01-01

    Full Text Available Abstract Background Inkjet micropatterning is a versatile deposition technique with broad applications in numerous fields. However, its application in plant science is largely unexplored. Leaf expansion is one of the most important parameters in the field of plant science and many methods have been developed to examine differential expansion rates of different parts of the leaf lamina. Among them, methods based on the tracking of natural landmarks through digital imaging require a complicated setup in which the leaf must remain fixed and under tension. Furthermore, the resolution is limited to that of the natural landmarks, which are often difficult to find, particularly in young leaves. To study the fine scale expansion dynamics of the leaf lamina using artificial landmarks it is necessary to place small, noninvasive marks on a leaf surface and then recover the location of those marks after a period of time. Results To monitor leaf expansion in two dimensions, at very fine scales, we used a custom designed inkjet micropatterning system to print a grid composed of c. 0.19 mm2 cells on small developing leaves of ivy (Hedera helix using 40 μm dots at a spacing of c. 91 μm. The leaves in different growing stages were imaged under magnification to extract the coordinates of the marks which were then used in subsequent computer-assisted leaf expansion analyses. As an example we obtained quantified global and local expansion information and created expansion maps over the entire leaf surface. The results reveal a striking pattern of fine-scale expansion differences over short periods of time. In these experiments, the base of the leaf is a "cold spot" for expansion, while the leaf sinuses are "hot spots" for expansion. We have also measured a strong shading effect on leaf expansion. We discuss the features required to build an inkjet printing apparatus optimized for use in plant science, which will further maximize the range of tissues that can be

  16. Kaolin-based foliar reflectant and water deficit influence Malbec leaf and berry temperature, pigments, and photosynthesis

    Science.gov (United States)

    The effects of a kaolin-based foliar reflectant on traits of commercial interest in the red-skinned wine grape cultivar Malbec (Vitis vinifera L.) were evaluated over three growing seasons by measuring the surface temperatures of leaves and clusters, leaf-level assimilation, leaf and berry pigment c...

  17. Leaf-produced floral signals.

    Science.gov (United States)

    Zeevaart, Jan A D

    2008-10-01

    Florigen is the hypothetical leaf-produced signal that induces floral initiation at the shoot apex. The nature of florigen has remained elusive for more than 70 years. But recent progress toward understanding the regulatory network for flowering in Arabidopsis has led to the suggestion that FLOWERING LOCUS T (FT) or its product is the mobile flower-inducing signal that moves from an induced leaf through the phloem to the shoot apex. In the past year, physical and chemical evidence has shown that it is FT protein, and not FT mRNA, that moves from induced leaves to the apical meristem. These results have established that FT is the main, if not the only, component of the universal florigen.

  18. Photosynthesis in developing leaf of juveniles and adults of three Mediterranean species with different growth forms.

    Science.gov (United States)

    Chondrogiannis, Christos; Grammatikopoulos, George

    2016-12-01

    Leaf development is influenced by almost all the prevailing environmental conditions as well as from the conditions at the time of bud formation. Furthermore, the growth form of a plant determines the leaf longevity and subsequently the investment in biomass and the internal structure of the mesophyll. Therefore, photosynthetic traits of a growing leaf, though, partly predetermined, should also acclimate to temporal changes during developmental period. In addition, the age of the plant can affect photosynthesis of the growing leaf, yet, in the majority of studies, the age is associated to the size of the plant. To test if the reproductive status of the plant affects the time kinetics of the photosynthetic capacity of a growing leaf and the relative contribution of the plants' growth form to the whole procedure, field measurements were conducted in juveniles (prereproductive individuals) and adults (fully reproductive individuals) of an evergreen sclerophyllous shrub (Nerium oleander), a semi-deciduous dimorphic shrub (Phlomis fruticosa), and a winter deciduous tree with pre-leafing flowering (Cercis siliquastrum). PSII structural and functional integrity was progressively developed in all species, but already completed, only some days after leaf expansion in P. fruticosa. Developing leaf as well as fully developed leaf in adults of C. siliquastrum showed enhanced relative size of the pool of final PSI electron acceptors. Photosynthetic traits between juveniles and adults of P. fruticosa were similar, though the matured leaf of adults exhibited lower transpiration rates and improved water-use efficiency than that of juveniles. Adults of the evergreen shrub attained higher CO2 assimilation rate than juveniles in matured leaf which can be attributed to higher electron flow devoted to carboxylation, and lower photorespiration rate. The reproductive phase of the plant seemed to be involved in modifications of the PSII and PSI functions of the deciduous tree, in

  19. Leaf wax n-alkane δD values are determined early in the ontogeny of Populus trichocarpa leaves when grown under controlled environmental conditions.

    Science.gov (United States)

    Kahmen, Ansgar; Dawson, Todd E; Vieth, Andrea; Sachse, Dirk

    2011-10-01

    The stable hydrogen isotope ratios (δD) of leaf wax n-alkanes record valuable information on plant and ecosystem water relations. It remains, however, unknown if leaf wax n-alkane δD values record only environmental variation during the brief period of time of leaf growth or if leaf wax n-alkane δD values are affected by environmental variability throughout the entire lifespan of a leaf. To resolve these uncertainties, we irrigated Populus trichocarpa trees with a pulse of deuterium-enriched water and used compound-specific stable hydrogen isotope analyses to test if the applied tracer could be recovered from leaf wax n-alkanes of leaves that were at different stages of their development during the tracer application. Our experiment revealed that only leaf wax n-alkanes from leaves that had developed during the time of the tracer application were affected, while leaves that were already fully matured at the time of the tracer application were not. We conclude from our study that under controlled environmental conditions, leaf wax n-alkanes are synthesized only early in the ontogeny of a leaf. Our experiment has implications for the interpretation of leaf wax n-alkane δD values in an environmental context, as it suggests that these compounds record only a brief period of the environmental variability that a leaf experiences throughout its life.

  20. Leaf thermal and hydraulic capacitances - structural safeguards for rapid ambient fluctuations

    Science.gov (United States)

    Schymanski, S. J.; Or, D.; Zwieniecki, M.

    2011-12-01

    Leaves may be subjected to rapidly fluctuating irradiation or thermal conditions due to motion of sun flecks and clouds or passage of warm and dry wind gusts. Given a stomatal characteristic time scale (~5 min) for adjusting transpiration flux, fluctuations of environmental conditions at shorter time scales (~1 min) could push leaf hydraulic and thermal status beyond its operational limits resulting in xylem cavitation or overheating. As active stomatal protection may not be adequate, we propose that leaf thermal and hydraulic capacitances and hence leaf specific mass (hydrated thickness) provide passive protection and play a critical role for autonomous and intrinsic capacitive-based responses to rapid fluctuations. For example, a simple variable leaf mass per unit area can affect both thermal and hydraulic capacitances. Thus a thin leaf (0.2 mm) exposed to a sunfleck can experience an increase in leaf temperature by 20K in the order of 3 minutes, i.e. before stomata can activate evaporative cooling. Increasing leaf thickness can be an effective measure to increase the buffer for such environmental fluctuations, so that slower regulatory measures such as stomatal adjustments can take over before detrimental effects take place. Systematic measurements of thermal changes in response to step changes in radiation conditions were obtained using laser illumination and infra-red thermal imaging of leaf laser-illuminated area across a wide range of leaf morphologies from major plant divisions (ferns, gymnosperms and angiosperms). Results confirm inverse relationships between leaf thickness and temperature rise (measured as steady state temperature increase). Hydraulic impacts of such structural capacitance on xylem function will be discussed.

  1. Micromorphology and histochemistry of leaf trichomes of Salvia aegyptiaca (Lamiaceae

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    Janošević Dušica

    2016-01-01

    Full Text Available We performed a comprehensive study of trichomes considering the medicinal importance of the essential oils produced in glandular trichomes of Salvia aegyptiaca L. and lack of data about leaf trichome characteristics. Micromorphological and histochemical analyses of the trichomes of S. aegyptiaca were carried out using light and scanning electron microscopy. We report that the leaves contained abundant non-glandular unbranched trichomes and two types of glandular trichomes, peltate and capitate, on both leaf surfaces. The abaxial leaf side was covered with numerous peltate and capitate trichomes, while capitate trichomes were more abundant on the adaxial leaf side, where peltate trichomes were rarely observed. The non-glandular trichomes were unicellular papillae and multicellular, uniseriate, two-to-six-celled, erect or slightly leaning toward the epidermis. Peltate trichomes were composed of a basal cell, a short cylindrical stalk cell and a broad head of eight secretory cells arranged in a single circle. Capitate trichomes consisted of a one-celled glandular head, subtended by a stalk of variable length, and classified into two types: capitate trichomes type I (or short-stalked glandular trichomes and capitate trichomes type II (or long-stalked glandular trichomes. Histochemical tests showed that the secreted material in all types of S. aegyptiaca glandular trichomes was of a complex nature. Positive reactions to lipids for both types of glandular trichomes were obtained, with especially abundant secretion observed in peltate and capitate trichomes type II. [Projekat Ministarstva nauke Republike Srbije, br. 173015 i br. 173029

  2. On the relationship between leaf photosynthetic capacity and leaf chlorophyll and implications for simulating GPP in space and time

    Science.gov (United States)

    Houborg, R.; Cescatti, A.; Migliavacca, M.

    2012-12-01

    Advancing the use of remote sensing data for retrieving key vegetation physiological controls is of critical importance for modeling spatio-temporal variations in gross primary productivity (GPP) with high fidelity. Key land-surface model controls on GPP, such as the maximum rate of carboxylation (Vcmax) that governs leaf photosynthetic efficiency, are typically assigned fixed literature-based values for broad categories of vegetation types although in reality temporal and spatial variability can be significant in response to differences in plant phenology and physiological condition, nutrient availability and climate. Vcmax defines the biochemical capacity of leaves to assimilate CO2 and is related to the nitrogen content of leaves, which is indirectly related to leaf reflectance and transmittance spectra. However, the fact that Vcmax is a leaf level parameter complicates larger scale parameterizations based on remote sensing observations due to confounding influences from the canopy and soil. Thus a key challenge is to separate the leaf contribution associated with changes in Vcmax from the total remote sensing signal. Chlorophylls are vital pigments for photosynthesis and directly controls leaf absorption in the visible waveband region. Here we report on the utility of satellite-based leaf chlorophyll (Chl) retrievals for quantifying Vcmax variability in space and time, and look into a mechanistic methodology for exploiting Chl information within the Community Land Model (CLM4) for improved predictability of GPP. Chl is retrieved from Landsat imagery by inversion of leaf optics and canopy reflectance models within the framework of REGFLEC (REGularized canopy reFLECtance tool). The potential of Chl retrievals for constraining model simulations of GPP is evaluated at multiple flux tower sites.ig. 1 Benefit of using satellite-based leaf chlorophyll (Chl) for parameterizing Vcmax and constraining modeled carbon fluxes over the growing season at a corn site in

  3. Spatial variation of dosimetric leaf gap and its impact on dose delivery

    Energy Technology Data Exchange (ETDEWEB)

    Kumaraswamy, Lalith K., E-mail: Lalith.Kumaraswamy@roswellpark.org [Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 and Department of Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Schmitt, Jonathan D. [Department of Radiation Medicine, RadAmerica, LLC-MedStar Health, Baltimore, Maryland 21237 (United States); Bailey, Daniel W. [Department of Radiation Oncology, Northside Hospital, Atlanta, Georgia 30342 (United States); Xu, Zheng Zheng [Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 and Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York 14260 (United States); Podgorsak, Matthew B. [Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Department of Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York 14260 (United States)

    2014-11-01

    Purpose: During dose calculation, the Eclipse treatment planning system (TPS) retracts the multileaf collimator (MLC) leaf positions by half of the dosimetric leaf gap (DLG) value (measured at central axis) for all leaf positions in a dynamic MLC plan to accurately model the rounded leaf ends. The aim of this study is to map the variation of DLG along the travel path of each MLC leaf pair and quantify how this variation impacts delivered dose. Methods: 6 MV DLG values were measured for all MLC leaf pairs in increments of 1.0 cm (from the line intersecting the CAX and perpendicular to MLC motion) to 13.0 cm off axis distance at dmax. The measurements were performed on two Varian linear accelerators, both employing the Millennium 120-leaf MLCs. The measurements were performed at several locations in the beam with both a Sun Nuclear MapCHECK device and a PTW pinpoint ion chamber. Results: The measured DLGs for the middle 40 MLC leaf pairs (each 0.5 cm width) at positions along a line through the CAX and perpendicular to MLC leaf travel direction were very similar, varying maximally by only 0.2 mm. The outer 20 MLC leaf pairs (each 1.0 cm width) have much lower DLG values, about 0.3–0.5 mm lower than the central MLC leaf pair, at their respective central line position. Overall, the mean and the maximum variation between the 0.5 cm width leaves and the 1.0 cm width leaf pairs are 0.32 and 0.65 mm, respectively. Conclusions: The spatial variation in DLG is caused by the variation of intraleaf transmission through MLC leaves. Fluences centered on the CAX would not be affected since DLG does not vary; but any fluences residing significantly off axis with narrow sweeping leaves may exhibit significant dose differences. This is due to the fact that there are differences in DLG between the true DLG exhibited by the 1.0 cm width outer leaves and the constant DLG value utilized by the TPS for dose calculation. Since there are large differences in DLG between the 0.5 cm width

  4. Comparative morphology of leaf epidermis in eight populations of Atlas Pistachio (Pistacia atlantica Desf., Anacardiaceae).

    Science.gov (United States)

    Belhadj, Safia; Derridj, Arezki; Aigouy, Thierry; Gers, Charles; Gauquelin, Thierry; Mevy, Jean-Philippe

    2007-10-01

    A comparative analysis was undertaken to conduct a micromorphological study of Pistacia atlantica leaves by comparing different populations grown under different climatic conditions. Leaf epidermis of eight wild populations was investigated under scanning electron microscope. Micromorphological characteristics (epidermis ornament, stomata type, waxes as well as trichomes) of the adaxial and abaxial leaf surfaces were examined. The epidermis ornament varied among populations and leaf surface, the abaxial leaf surface is reticulate with a striate surface. Messaad site shows a smooth uneven surface. The adaxial leaf surface is smooth but several ornamentations can be seen. The leaflet is amphistomatic; the stomata appeared to be slightly sunken. A variety of stomatal types were recorded; actinocytic and anomocytic types are the most frequent. The indumentum consisted of glandular and nonglandular trichomes. Unicellular glandular trichomes are recorded for P. atlantica leaves in this study. Their density is higher in Oued safene site, located at the highest altitude in comparison with the other populations. The wax occurred in all the sites and its pattern varied according to the populations studied, particularly between Berriane and Messaad. The morphological variability exhibited by the eight populations of P. atlantica may be interpreted as relevant to the ecological plasticity and the physiological mechanisms involved are discussed in this report.

  5. Molecular Characterization of Tomato leaf curl Palampur virus and Pepper leaf curl betasatellite Naturally Infecting Pumpkin (Cucurbita moschata) in India.

    Science.gov (United States)

    Namrata, Jaiswal; Saritha, R K; Datta, D; Singh, M; Dubey, R S; Rai, A B; Rai, M

    2010-10-01

    Pumpkin cultivation in India is affected by severe incidence of a yellow vein mosaic disease. Tomato leaf curl New Delhi virus and Squash leaf curl China virus are known to be associated with this disease in India. We were able to identify a third begomovirus-Tomato leaf curl Palampur virus (ToLCPMV), from pumpkin showing typical symptoms of the disease at Varanasi based on the sequence of complete DNA-A genome of the virus. The complete DNA-A sequence of the virus shared more than 99% sequence identity with other ToLCPMV isolates available in the GenBank and clustered with them in the phylogenetic analysis. This betasatellite amplified from the same infected sample has been identified as Pepper leaf curl betasatellite (PepLCB) which also infects chilli in India. There was 92% sequence identity between the two isolates. This is the first report of natural infection of ToLCPMV on pumpkin and association of PepLCB with yellow vein mosaic disease of pumpkin in India.

  6. Fire ants protect mealybugs against their natural enemies by utilizing the leaf shelters constructed by the leaf roller Sylepta derogata.

    Directory of Open Access Journals (Sweden)

    Aiming Zhou

    Full Text Available The importance of mutualism is receiving more attention in community ecology. In this study, the fire ant Solenopsis invicta was found to take advantage of the shelters constructed by the leaf roller Sylepta derogata to protect mealybugs (Phenacoccus solenopsis against their natural enemies. This protective effect of fire ant tending on the survival of mealybugs in shelters was observed when enemies and leaf rollers were simultaneously present. Specifically, fire ants moved the mealybugs inside the shelters produced by S. derogata on enemy-infested plants. Compared with that in plants without ants, the survival of mealybugs in shelters in the presence of natural enemies in plants with ants markedly improved. Both the protection of ants and the shelters provided by leaf rollers did not affect the survival of mealybugs in the absence of enemies in plants. Ants and leaf rollers significantly improved the survival of mealybugs in predator-infested plants, whereas no such improvement was observed in parasitoid-infested ones.

  7. Correlated evolution of leaf shape and trichomes in Begonia dregei (Begoniaceae).

    Science.gov (United States)

    McLellan, Tracy

    2005-10-01

    Structural features of leaves, including size, shape, and surfaces, vary greatly throughout the plant kingdom. In both functional and phylogenetic analyses of leaves, the various morphological aspects are often considered independently of each other, although it is likely that many combinations of features do not occur at random due to either functional constraint or genetic correlation. The distribution of variation in leaf morphology in the highly variable Begonia dregei species complex was examined in natural populations and in F(2) offspring from a cross between plants from two populations. Leaf shape was quantified using several morphometric measures, and trichomes on leaves were counted and measured. Correlations between leaf shape and the numbers and size of trichomes were examined. There were significant correlations between the shapes of leaves and the presence, number, and size of trichomes among populations and in hybrid plants. Deeply incised leaves had larger numbers of longer trichomes at the sinuses. Higher numbers of trichomes on upper leaf surfaces occurred together with trichomes at the petiole and on the abaxial surface. The potential for independent evolution of leaf shape and trichomes in this group is limited. Hypotheses to explain the correlated development of leaf shape and trichomes are discussed.

  8. Estimation of stand-level leaf area for boreal bryophytes.

    Science.gov (United States)

    Bond-Lamberty, Ben; Gower, Stith T

    2007-04-01

    Bryophytes dominate the carbon and nitrogen cycling of many poorly drained terrestrial ecosystems and are important in the vegetation-atmosphere exchange of carbon and water, yet few studies have estimated their leaf area at the stand scale. This study quantified the bryophyte-specific leaf area (SLA) and leaf area index (LAI) in a group of different-aged boreal forest stands in well and poorly drained soils. Species-specific SLA (for three feather mosses, four Sphagnum spp. and Aulacomnium palustre mixed with Tomentypnum nitens) was assessed by determining the projected area using a flatbed scanner and cross-sectional geometry using a dissecting microscope. The hemisurface leaf area was computed as the product of SLA and live biomass and was scaled by coverage data collected at all stands. Pleurozium schreberi dominated the spatial coverage, biomass and leaf area in the well-drained stands, particularly the oldest, while S. fuscum and A. palustre were important in the poorly drained stands. Live moss biomass ranged from 47 to 230 g m(-2) in the well-drained stands dominated by feather mosses and from 102 to 228 g m(-2) in the poorly drained stands. Bryophyte SLA varied between 135 and 473 cm(2) g(-1), for A. palustre and S. capillifolium, respectively. SLA was strongly and significantly affected by bryophyte species, but did not vary between stands; in general, there was no significant difference between the SLA of non-Sphagnum mosses. Bryophyte LAI increased with stand age, peaking at 3.1 and 3.7 in the well and poorly drained stands, respectively; this represented approximately 40% of the overstory LAI in the well-drained stands and 100-1,000% in the poorly drained stands, underscoring the important role bryophytes play in the water and carbon budgets of these boreal forests.

  9. Hormonal Regulation of Leaf Morphogenesis in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Lin-Chuan Li; Ding-Ming Kang; Zhang-Liang Chen; Li-Jia Qu

    2007-01-01

    Leaf morphogenesis is strictly controlled not only by intrinsic genetic factors, such as transcriptional factors, but also by environmental cues, such as light, water and pathogens. Nevertheless, the molecular mechanism of how leaf rnorphogenesis is regulated by genetic programs and environmental cues is far from clear. Numerous series of events demonstrate that plant hormones, mostly small and simple molecules,play crucial roles in plant growth and development, and in responses of plants to environmental cues such as light. With more and more genetics and molecular evidence obtained from the model plant Arabidopsis,several fundamental aspects of leaf rnorphogenesis including the initiation of leaf primordia, the determination of leaf axes, the regulation of cell division and expansion in leaves have been gradually unveiled.Among these phytohormones, auxin is found to be essential in the regulation of leaf morphogenesis.

  10. Do climate and soil influence phenotypic variability in leaf litter, microbial decomposition and shredder consumption?

    Science.gov (United States)

    Graça, M A S; Poquet, J M

    2014-03-01

    We tested the hypothesis that water stress and soil nutrient availability drive leaf-litter quality for decomposers and detritivores by relating chemical and physical leaf-litter properties and decomposability of Alnus glutinosa and Quercus robur, sampled together with edaphic parameters, across wide European climatic gradients. By regressing principal components analysis of leaf traits [N, P, condensed tannins, lignin, specific leaf area (SLA)] against environmental and soil parameters, we found that: (1) In Q. robur the condensed tannin and lignin contents increased and SLA decreased with precipitation, annual range of temperature, and soil N content, whereas leaf P increased with soil P and temperature; (2) In A. glutinosa leaves N, P, and SLA decreased and condensed tannins increased with temperature, annual range of temperature, and decreasing soil P. On the other hand, leaf P and condensed tannins increased and SLA decreased with minimum annual precipitation and towards sites with low temperature. We selected contrasting leaves in terms of quality to test decomposition and invertebrate consumption. There were intraspecific differences in microbial decomposition rates (field, Q. robur) and consumption by shredders (laboratory, A. glutinosa). We conclude that decomposition rates across ecosystems could be partially governed by climate and soil properties, affecting litter quality and therefore decomposers and detritivores. Under scenarios of global warming and increased nutrients, these results suggest we can expect species-specific changes in leaf-litter properties most likely resulting in slow decomposition with increased variance in temperatures and accelerated decomposition with P increase.

  11. Leaf shape responds to temperature but not CO2 in Acer rubrum.

    Directory of Open Access Journals (Sweden)

    Dana L Royer

    Full Text Available The degree of leaf dissection and the presence of leaf teeth, along with tooth size and abundance, inversely correlate with mean annual temperature (MAT across many plant communities. These relationships form the core of several methods for reconstructing MAT from fossils, yet the direct selection of temperature on tooth morphology has not been demonstrated experimentally. It is also not known if atmospheric CO(2 concentration affects leaf shape, limiting confidence in ancient climate reconstructions because CO(2 has varied widely on geologic timescales. Here I report the results of growing Acer rubrum (red maple in growth cabinets at contrasting temperature and CO(2 conditions. The CO(2 treatment imparted no significant differences in leaf size and shape, while plants grown at cooler temperatures tended to have more teeth and more highly dissected leaves. These results provide direct evidence for the selection of temperature on leaf shape in one species, and support a key link in many leaf-climate methods. More broadly, these results increase confidence for using leaf shape in fossils to reconstruct paleoclimate.

  12. Leaf shape responds to temperature but not CO2 in Acer rubrum.

    Science.gov (United States)

    Royer, Dana L

    2012-01-01

    The degree of leaf dissection and the presence of leaf teeth, along with tooth size and abundance, inversely correlate with mean annual temperature (MAT) across many plant communities. These relationships form the core of several methods for reconstructing MAT from fossils, yet the direct selection of temperature on tooth morphology has not been demonstrated experimentally. It is also not known if atmospheric CO(2) concentration affects leaf shape, limiting confidence in ancient climate reconstructions because CO(2) has varied widely on geologic timescales. Here I report the results of growing Acer rubrum (red maple) in growth cabinets at contrasting temperature and CO(2) conditions. The CO(2) treatment imparted no significant differences in leaf size and shape, while plants grown at cooler temperatures tended to have more teeth and more highly dissected leaves. These results provide direct evidence for the selection of temperature on leaf shape in one species, and support a key link in many leaf-climate methods. More broadly, these results increase confidence for using leaf shape in fossils to reconstruct paleoclimate.

  13. Effects of precipitation regime and soil nitrogen on leaf traits in seasonally dry tropical forests of the Yucatan Peninsula, Mexico.

    Science.gov (United States)

    Roa-Fuentes, Lilia L; Templer, Pamela H; Campo, Julio

    2015-10-01

    Leaf traits are closely associated with nutrient use by plants and can be utilized as a proxy for nutrient cycling processes. However, open questions remain, in particular regarding the variability of leaf traits within and across seasonally dry tropical forests. To address this, we considered six leaf traits (specific area, thickness, dry matter content, N content, P content and natural abundance (15)N) of four co-occurring tree species (two that are not associated with N2-fixing bacteria and two that are associated with N2-fixing bacteria) and net N mineralization rates and inorganic N concentrations along a precipitation gradient (537-1036 mm per year) in the Yucatan Peninsula, Mexico. Specifically we sought to test the hypothesis that leaf traits of dominant plant species shift along a precipitation gradient, but are affected by soil N cycling. Although variation among different species within each site explains some leaf trait variation, there is also a high level of variability across sites, suggesting that factors other than precipitation regime more strongly influence leaf traits. Principal component analyses indicated that across sites and tree species, covariation in leaf traits is an indicator of soil N availability. Patterns of natural abundance (15)N in foliage and foliage minus soil suggest that variation in precipitation regime drives a shift in plant N acquisition and the openness of the N cycle. Overall, our study shows that both plant species and site are important determinants of leaf traits, and that the leaf trait spectrum is correlated with soil N cycling.

  14. H2O2-induced Leaf Cell Death and the Crosstalk of Reactive Nitric/Oxygen Species([F])

    Institute of Scientific and Technical Information of China (English)

    Yiqin Wang; Aihong Lin; Gary J.Loake; Chengcai Chu

    2013-01-01

    In plants,the chloroplast is the main reactive oxygen species (ROS) producing site under high light stress.Catalase (CAT),which decomposes hydrogen peroxide (H2O2),is one of the controlling enzymes that maintains leaf redox homeostasis.The catalase mutants with reduced leaf catalase activity from different plant species exhibit an H2O2-induced leaf cell death phenotype.This phenotype was differently affected by light intensity or photoperiod,which may be caused by plant species,leaf redox status or growth conditions.In the rice CAT mutant nitric oxide excess 1 (noe1),higher H2O2 levels induced the generation of nitric oxide (NO) and higher S-nitrosothiol (SNO) levels,suggesting that NO acts as an important endogenous mediator in H2O2-induced leaf cell death.As a free radical,NO could also react with other intracellular and extracellular targets and form a series of related molecules,collectively called reactive nitrogen species (RNS).Recent studies have revealed that both RNS and ROS are important partners in plant leaf cell death.Here,we summarize the recent progress on H2O2-induced leaf cell death and the crosstalk of RNS and ROS signals in the plant hypersensitive response (HR),leaf senescence,and other forms of leaf cell death triggered by diverse environmental conditions.

  15. Joint leaf chlorophyll and leaf area index retrieval using a regularized canopy reflectance model inversion system

    Science.gov (United States)

    Houborg, R.; McCabe, M. F.; Gitelson, A. A.

    2013-12-01

    Leaf area index (LAI) and leaf chlorophyll (Chl) represent key biophysical and biochemical controls on water, energy and carbon exchange processes in the terrestrial biosphere. In combination LAI and Chl provide critical information on vegetation density and phenology, the vitality of vegetation and photosynthetic functioning, and joint satellite-based retrievals can be used to inform land surface models and reduce uncertainties of model predicted ecosystem fluxes in space and time. Simultaneous retrieval of LAI and Chl from space observations is however extremely challenging as the interference of atmospheric effects, canopy characteristics and background reflectance may confound the detection of relatively subtle differences in canopy reflectance resulting from changes in Chl. Regularization strategies are therefore required to increase robustness and accuracy of retrieved properties and more reliably separate soil, leaf and canopy variables. Here we describe recent refinements to the REGularized canopy reFLECtance model (REGFLEC) retrieval system, which includes enhanced regularization techniques for exploiting ancillary LAI and temporal information derived from multiple satellite scenes over a given growing season. REGFLEC is applied to Landsat time-series data and retrieval results evaluated against in-situ LAI and Chl collected over maize and soybean sites in central Nebraska over a 5-year period (2001-2005). While REGFLEC may provide useful information on the density and vitality of vegetation, the results reflect the challenges associated with accurately extracting the relatively small leaf-level chlorophyll signal from the total satellite signal when using a few standard broad bands available operationally (i.e. blue, green, red and near-infrared) as input to a homogeneous canopy reflectance model. A noteworthy and novel aspect of the REGFLEC approach is the fact that no site-specific data were used to calibrate the model that may be run in a completely

  16. [Applicability analysis of spatially explicit model of leaf litter in evergreen broad-leaved forests].

    Science.gov (United States)

    Zhao, Qing-Qing; Liu, He-Ming; Jonard, Mathieu; Wang, Zhang-Hua; Wang, Xi-Hua

    2014-11-01

    The spatially explicit model of leaf litter can help to understand its dispersal process, which is very important to predict the distribution pattern of leaves on the surface of the earth. In this paper, the spatially explicit model of leaf litter was developed for 20 tree species using litter trap data from the mapped forest plot in an evergreen broad-leaved forest in Tiantong, Zhejiang Pro- vince, eastern China. Applicability of the model was analyzed. The model assumed an allometric equation between diameter at breast height (DBH) and leaf litter amount, and the leaf litter declined exponentially with the distance. Model parameters were estimated by the maximum likelihood method. Results showed that the predicted and measured leaf litter amounts were significantly correlated, but the prediction accuracies varied widely for the different tree species, averaging at 49.3% and ranging from 16.0% and 74.0%. Model qualities of tree species significantly correlated with the standard deviations of the leaf litter amount per trap, DBH of the tree species and the average leaf dry mass of tree species. There were several ways to improve the forecast precision of the model, such as installing the litterfall traps according to the distribution of the tree to cover the different classes of the DBH and distance apart from the parent trees, determining the optimal dispersal function of each tree species, and optimizing the existing dispersal function.

  17. Compound leaf development in model plant species.

    Science.gov (United States)

    Bar, Maya; Ori, Naomi

    2015-02-01

    Plant leaves develop in accordance with a common basic program, which is flexibly adjusted to the species, developmental stage and environment. Two key stages of leaf development are morphogenesis and differentiation. In the case of compound leaves, the morphogenesis stage is prolonged as compared to simple leaves, allowing for the initiation of leaflets. Here, we review recent advances in the understanding of how plant hormones and transcriptional regulators modulate compound leaf development, yielding a substantial diversity of leaf forms, focusing on four model compound leaf organisms: cardamine (Cardamine hirsuta), tomato (Solanum lycopersicum), medicago (Medicago truncatula) and pea (Pisum sativum).

  18. Transcriptional networks in leaf senescence.

    Science.gov (United States)

    Schippers, Jos H M

    2015-10-01

    Plant senescence is a natural phenomenon known for the appearance of beautiful autumn colors and the ripening of cereals in the field. Senescence is a controlled process that plants utilize to remobilize nutrients from source leaves to developing tissues. While during the past decades, molecular components underlying the onset of senescence have been intensively studied, knowledge remains scarce on the age-dependent mechanisms that control the onset of senescence. Recent advances have uncovered transcriptional networks regulating the competence to senesce. Here, gene regulatory networks acting as internal timing mechanisms for the onset of senescence are highlighted, illustrating that early and late leaf developmental phases are highly connected.

  19. Does a large dehiscent implant surface at placement affect the 5-year treatment outcome? : An assessment of implants placed to support a maxillary overdenture

    NARCIS (Netherlands)

    Boven, G. C.; Meijer, H. J. A.; Slot, W.; Vissink, A.; Raghoebar, G. M.

    2015-01-01

    The aim of this study was to assess the 5-year clinical and radiographic outcome of implants with a dehiscent surface at implant placement. A total of 26 consecutive patients (mean age 61.6 years; SD 8.0 years) with at least one implant with a dehiscent implant surface of >= two thirds of the implan

  20. Derivation of elastic stiffness formula for leaf type HDS and conceptual design of leaf type HDS of SMART FA

    Energy Technology Data Exchange (ETDEWEB)

    Song, Kee Nam; Kang, Heung Seok; Yoon, Kyung Ho; Suh, Jung Min; Lee, Jin Seok

    1997-12-01

    Based on the strain energy method and Euler beam theory, an elastic stiffness formula for the leaf type HDS, now widely used as the holddown spring for the FA of Westinghouse type PWRs, has been derived. Through comparisons with the characteristic test results of the test produced HDSs, it has been found that the derived formula is useful to reliably estimate an elastic stiffness with material properties and the geometric data of an HDS. Through sensitivity analysis of HDS`s elastic stiffness, the elastic stiffness sensitivity with respect to different design variables was identified, as well as the design variables having remarkable sensitivity. In addition, finite element analysis using surface-to-surface contact elements on the contact surface between the leaves shows that the analysis results are in good agreement with the elastic stiffness determined from the derived formula. It is therefore expected that the finite element model and the analysis method will be useful in the analysis of the elasto-plastic behavior of the leaf type HDS in the future. To both reduce the cobalt content, which is considered to be the source of radioactive contamination in the reactor core, and to design the HDS to meet the holddown requirements of the SMART FA, a conceptual design for the HDS of the SMART FA has been performed through two analyses of the elastic characteristics of the HDS : the possibility of substitution of the leaf spring`s material from Inconel 718 to Zircaloy and the effects on the HDS`s elastic characteristics according to the variation of leaf thickness and the number of leaves composing the HDS. (author). 34 refs., 33 tabs., 37 figs.

  1. 7 CFR 28.467 - Leaf Grade 7.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 7. 28.467 Section 28.467 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.467 Leaf Grade 7. Leaf Grade 7 is leaf which is within the range represented...

  2. 7 CFR 28.465 - Leaf Grade 5.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 5. 28.465 Section 28.465 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.465 Leaf Grade 5. Leaf Grade 5 is leaf which is within the range represented...

  3. 7 CFR 28.462 - Leaf Grade 2.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 2. 28.462 Section 28.462 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.462 Leaf Grade 2. Leaf Grade 2 is leaf which is within the range represented...

  4. 7 CFR 28.463 - Leaf Grade 3.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 3. 28.463 Section 28.463 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.463 Leaf Grade 3. Leaf Grade 3 is leaf which is within the range represented...

  5. 7 CFR 28.461 - Leaf Grade 1.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 1. 28.461 Section 28.461 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.461 Leaf Grade 1. Leaf Grade 1 is leaf which is within the range represented...

  6. 7 CFR 28.471 - Below Leaf Grade Cotton.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Below Leaf Grade Cotton. 28.471 Section 28.471... REGULATIONS COTTON CLASSING, TESTING, AND STANDARDS Standards Below Leaf Grade Cotton § 28.471 Below Leaf Grade Cotton. Below leaf grade cotton is American Upland cotton which is lower in leaf grade than...

  7. 7 CFR 28.466 - Leaf Grade 6.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 6. 28.466 Section 28.466 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.466 Leaf Grade 6. Leaf Grade 6 is leaf which is within the range represented...

  8. 7 CFR 28.464 - Leaf Grade 4.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 4. 28.464 Section 28.464 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.464 Leaf Grade 4. Leaf Grade 4 is leaf which is within the range represented...

  9. Shifts in leaf litter breakdown along a forest-pasture-urban gradient in Andean streams.

    Science.gov (United States)

    Iñiguez-Armijos, Carlos; Rausche, Sirkka; Cueva, Augusta; Sánchez-Rodríguez, Aminael; Espinosa, Carlos; Breuer, Lutz

    2016-07-01

    Tropical montane ecosystems of the Andes are critically threatened by a rapid land-use change which can potentially affect stream variables, aquatic communities, and ecosystem processes such as leaf litter breakdown. However, these effects have not been sufficiently investigated in the Andean region and at high altitude locations in general. Here, we studied the influence of land use (forest-pasture-urban) on stream physico-chemical variables (e.g., water temperature, nutrient concentration, and pH), aquatic communities (macroinvertebrates and aquatic fungi) and leaf litter breakdown rates in Andean streams (southern Ecuador), and how variation in those stream physico-chemical variables affect macroinvertebrates and fungi related to leaf litter breakdown. We found that pH, water temperature, and nutrient concentration increased along the land-use gradient. Macroinvertebrate communities were significantly different between land uses. Shredder richness and abundance were lower in pasture than forest sites and totally absent in urban sites, and fungal richness and biomass were higher in forest sites than in pasture and urban sites. Leaf litter breakdown rates became slower as riparian land use changed from natural to anthropogenically disturbed conditions and were largely determined by pH, water temperature, phosphate concentration, fungal activity, and single species of leaf-shredding invertebrates. Our findings provide evidence that leaf litter breakdown in Andean streams is sensitive to riparian land-use change, with urban streams being the most affected. In addition, this study highlights the role of fungal biomass and shredder species (Phylloicus; Trichoptera and Anchytarsus; Coleoptera) on leaf litter breakdown in Andean streams and the contribution of aquatic fungi in supporting this ecosystem process when shredders are absent or present low abundance in streams affected by urbanization. Finally, we summarize important implications in terms of managing of

  10. Inhibition of mild steel corrosion using Jatropha Curcas leaf extract

    Directory of Open Access Journals (Sweden)

    OLORUNFEMI MICHAEL AJAYI

    2014-05-01

    Full Text Available Jatropha Curcas leaf was investigated as a green inhibitor on the degradation of mild steel in 4 M HCl and 4 M H2SO4 aqueous solutions using gasometric technique. Mild steel coupons of dimension 2 × 1.5 cm were immersed in test solutions of uninhibited acid and also those with extract concentrations of 4 ml, 6 ml, 8 ml and 10 ml at 30 oC, for up to 30 minutes. The results showed that as the concentration of the extract increases, there was reduction in the corrosion rate. As the extract concentration increased from 4 ml to 10 ml at 30 minutes exposure, the volume of hydrogen gas evolved decreased from 19.1 cm3 to 11.2 cm3 in H2SO4 medium, while it reduced to 5 cm3 from 9 cm3 in HCl medium. Also, the metal surface-phytoconstituent interaction mechanism showed that 6 minutes is the best exposure time for the adsorption of the extract in both acidic media. The Jatropha Curcas leaf extract was adsorbed on the mild steel surface to inhibit corrosion, while the experimental data obtained at 30 minutes exposure in both acidic media were well fitted with the Langmuir adsorption isotherm. Hence, Jatropha Curcas leaf extract is a good and safe inhibitor in both acidic solutions.

  11. Trends in leaf photosynthesis in historical rice varieties developed in the Philippines since 1966.

    Science.gov (United States)

    Hubbart, S; Peng, S; Horton, P; Chen, Y; Murchie, E H

    2007-01-01

    Crop improvement in terms of yield is rarely linked to leaf photosynthesis. However, in certain crop plants such as rice, it is predicted that an increase in photosynthetic rate will be required to support future grain yield potential. In order to understand the relationships between yield improvement and leaf photosynthesis, controlled environment conditions were used to grow 10 varieties which were released from the International Rice Research Institute (IRRI) between 1966 and 1995 and one newly developed line. Two growth light intensities were used: high light (1500 micromol m(-2) s(-1)) and low light (300 micromol m(-2) s(-1)). Gas exchange, leaf protein, chlorophyll, and leaf morphology were measured in the ninth leaf on the main stem. A high level of variation was observed among high light-grown plants for light-saturated photosynthetic rate per unit leaf area (P(max)), stomatal conductance (g), content of ribulose bisphosphate carboxylase-oxygenase (Rubisco), and total leaf protein content. Notably, between 1966 and 1980 there was a decline in P(max), g, leaf protein, chlorophyll, and Rubisco content. Values recovered in those varieties released after 1980. This striking trend coincides with a previous published observation that grain yield in IRRI varieties released prior to 1980 correlated with harvest index whereas that for those released after 1980 correlated with biomass. P(max) showed significant correlations with both g and Rubisco content. Large differences were observed between high light- and low light-grown plants (photoacclimation). The photoacclimation 'range' for P(max) correlated with P(max) in high light-grown plants. It is concluded that (i) leaf photosynthesis may be systematically affected by breeding strategy; (ii) P(max) is a useful target for yield improvements where yield is limited by biomass production rather than partitioning; and (iii) the capacity for photoacclimation is related to high P(max) values.

  12. Upscaling Ozone Flux in Forests from Leaf to Landscape

    Directory of Open Access Journals (Sweden)

    Gerhard Wieser

    Full Text Available Although stomatal conductance for ozone (O3 correlates with leaf to air water vapor difference (VPDLA at the leaf level, uncertainty in up-scaling to the whole tree level can be overcome by means of sap flow measurements at the tree trunk. Further up-scaling to the stand level is possible by relating whole tree O3 flux to silvicultural and/or tree-allometric data. In such a way, canopy conductance and O3 uptake can be related to ground surface area. When normalized, canopy conductance is demonstrated to follow a functional relationship to VPDLA across several forest ecosystems thus allowing a generalization of model approaches. Further up-scaling to the landscape level, however, needs further investigations due to differences in the response of canopy conductance to environmental drivers in forest stands and grassland ecosystems, respectively.

  13. PERBEDAAN KANDUNGAN SENYAWA VOLATIL DAUN SALAM (Eugenia polyantha Wight) PADA BEBERAPA PROSES CURING The Difference of Volatile Compounds of Bay Leaf (Eugenia polyantha Wight.) in Several Curing Processes

    OpenAIRE

    2012-01-01

    The influence of curing process toward flavour substances of bay leaf has been conducted. Bay leaves were cured with three different time of process: 0, 2 and 4 days and extracted by simultaneous distillation-extraction using n- hexane. Flavour extract was evaporated by vacuum rotary evaporator and remained solvent was flushed with nitrogen gas. Flavour compounds of the bay leaf extract were analysed using GC-MS. The result showed that curing process affected the composition of bay leaf flavo...

  14. Relation between Silver Nanoparticle Formation Rate and Antioxidant Capacity of Aqueous Plant Leaf Extracts

    Directory of Open Access Journals (Sweden)

    Azat Akbal

    2016-01-01

    Full Text Available Correlation between the antioxidant capacity and silver nanoparticle formation rates of pomegranate (Punica granatum, quince (Cydonia oblonga, chestnut (Castanea sativa, fig (Ficus carica, walnut (Juglans cinerea, black mulberry (Morus nigra, and white mulberry (Morus alba leaf extracts is investigated at a fixed illumination. Silver nanoparticles formed in all plant leaf extracts possess round shapes with average particle size of 15 to 25 nm, whereas corresponding surface plasmon resonance peak wavelengths vary between 422 nm and 451 nm. Cupric reducing antioxidant capacity technique is used as a reference method to determine total antioxidant capacity of the plant leaf extracts. Integrated absorbance over the plasmon resonance peaks exhibits better linear relation with antioxidant capacities of various plant leaf extracts compared to peak absorbance values, with correlation coefficient values of 0.9333 and 0.7221, respectively.

  15. Evaluation of leaf removal as a means to reduce nutrient concentrations and loads in urban stormwater

    Science.gov (United States)

    Selbig, William R.

    2016-01-01

    While the sources of nutrients to urban stormwater are many, the primary contributor is often organic detritus, especially in areas with dense overhead tree canopy. One way to remove organic detritus before it becomes entrained in runoff is to implement a city-wide leaf collection and street cleaning program. Improving our knowledge of the potential reduction of nutrients to stormwater through removal of leaves and other organic detritus on streets could help tailor more targeted municipal leaf collection programs. This study characterized an upper ideal limit in reductions of total and dissolved forms of phosphorus and nitrogen in stormwater through implementation of a municipal leaf collection and street cleaning program in Madison, WI, USA. Additional measures were taken to remove leaf litter from street surfaces prior to precipitation events.

  16. Compensatory responses in plant-herbivore interactions: Impacts of insects on leaf water relations

    Science.gov (United States)

    Peschiutta, María L.; Bucci, Sandra J.; Scholz, Fabián G.; Goldstein, Guillermo

    2016-05-01

    Herbivore damage to leaves has been typically evaluated in terms of fractions of area removed; however morpho-physiological changes in the remaining tissues can occur in response to removal. We assessed the effects of partial removal of the leaf mesophyll by Caliroa cerasi (Hymenoptera) on leaf hydraulic conductance (Kleaf), vascular architecture, water relations and leaf size of three Prunus avium cultivars. The insect feeds on the leaf mesophyll leaving the vein network intact (skeletonization). Within each cultivar there were trees without infestations and trees chronically infested, at least over the last three years. Leaf size of intact leaves tended to be similar during leaf expansion before herbivore attack occurs across infested and non-infested trees. However, after herbivore attack and when the leaves were fully expanded, damaged leaves were smaller than leaves from non-infested trees. Damaged area varied between 21 and 31% depending on cultivar. The non-disruption of the vascular system together with either vein density or capacitance increased in damaged leaves resulted in similar Kleaf and stomatal conductance in infested and non-infested trees. Non-stomatal water loss from repeated leaf damage led to lower leaf water potentials in two of the infested cultivars. Lower leaf osmotic potentials and vulnerability to loss of Kleaf were observed in infested plants. Our results show that skeletonization resulted in compensatory changes in terms of water relations and hydraulics traits and in cultivar-specific physiological changes in phylogenetic related P. avium. Our findings indicate that detrimental effects of herbivory on the photosynthetic surface are counterbalanced by changes providing higher drought resistance, which has adaptive significance in ecosystems where water availability is low and furthermore where global climate changes would decrease soil water availability in the future even further.

  17. Bleaching of leaf litter and associated microfungi in subboreal and subalpine forests.

    Science.gov (United States)

    Hagiwara, Yusuke; Matsuoka, Shunsuke; Hobara, Satoru; Mori, Akira S; Hirose, Dai; Osono, Takashi

    2015-10-01

    Fungal decomposition of lignin leads to the whitening, or bleaching, of leaf litter, especially in temperate and tropical forests, but less is known about such bleaching in forests of cooler regions, such as boreal and subalpine forests. The purposes of the present study were to examine the extent of bleached area on the surface of leaf litter and its variation with environmental conditions in subboreal and subalpine forests in Japan and to examine the microfungi associated with the bleaching of leaf litter by isolating fungi from the bleached portions of the litter. Bleached area accounted for 21.7%-32.7% and 2.0%-10.0% of total leaf area of Quercus crispula and Betula ermanii, respectively, in subboreal forests, and for 6.3% and 18.6% of total leaf area of B. ermanii and Picea jezoensis var. hondoensis, respectively, in a subalpine forest. In subboreal forests, elevation, C/N ratio and pH of the FH layer, and slope aspect were selected as predictor variables for the bleached leaf area. Leaf mass per area and lignin content were consistently lower in the bleached area than in the nonbleached area of the same leaves, indicating that the selective decomposition of acid unhydrolyzable residue (recalcitrant compounds such as lignin, tannins, and cutins) enhanced the mass loss of leaf tissues in the bleached portions. Isolates of a total of 11 fungal species (6 species of Ascomycota and 5 of Basidiomycota) exhibited leaf-litter-bleaching activity under pure culture conditions. Two fungal species (Coccomyces sp. and Mycena sp.) occurred in both subboreal and subalpine forests, which were separated from each other by approximately 1100 km.

  18. Nutrição e produtividade de grãos da aveia-preta em função da aplicação de calcário e gesso em superfície na implantação do sistema plantio direto Nutrition and grain yield of black oat as affected by surface application of lime and phosphogypsum at the establishment of no-tillage system

    Directory of Open Access Journals (Sweden)

    Rogério Peres Soratto

    2008-04-01

    Full Text Available A nutrição e produtividade das culturas podem ser afetadas pelas modificações químicas do solo causadas pela calagem e aplicação de gesso em superfície. Este trabalho objetivou avaliar o efeito da aplicação de calcário e gesso em superfície, na implantação do sistema plantio direto, sobre a nutrição e a produtividade de grãos da aveia-preta, em região de inverno seco, em área anteriormente utilizada com preparo convencional. O experimento foi realizado durante 2003 e 2004, em um Latossolo Vermelho distroférrico, em Botucatu (SP. O delineamento foi de blocos casualizados com parcelas subdivididas e quatro repetições. As parcelas (18,0 x 5,4 m foram constituídas por quatro doses de calcário dolomítico (0, 1.100, 2.700 e 4.300 kg ha-1, com PRNT = 71,2 %, e as subparcelas (9,0 x 5,4 m pela aplicação ou não de 2.100 kg ha-1 de gesso agrícola. O aumento no teor de Ca no solo, provocado pela aplicação de calcário e gesso, diminuiu o teor de Mg na folha bandeira da aveia-preta em ano com deficiência hídrica. A aplicação de calcário em superfície aumentou os teores de K e reduziu os de Cu e Fe, e a aplicação de gesso agrícola aumentou o teor de S na folha bandeira da aveia-preta. A calagem em superfície aumentou a produtividade de grãos da aveia-preta, em ano com deficiência hídrica, com efeitos mais pronunciados na presença de aplicação de gesso.Nutrition and crop yield can be affected by chemical modifications of the soil owing to lime and phosphogypsum surface application. The purpose of this study was to evaluate the effects of surface application of lime and phosphogypsum, at the establishment of a no-tillage system, on nutrition and grain yield of black oat, in a dry-winter region, in area previously used with conventional tillage. The experiment was carried out in 2003 and 2004, on a Haplorthox in Botucatu County, São Paulo State, Brazil. A randomized complete block design was used in a split

  19. The Effect of Adjuvants on Penetration of beta-cypermethrin Through the Epidermis of Cabbage Leaf

    Institute of Scientific and Technical Information of China (English)

    WANG Yi; ZHANG Li-ta; ZHENG Fei-neng; CHEN Fu-liang; LIANG Wen-ping

    2002-01-01

    The effects of three types of adjuvant (mineral oil, higher aliphatic acid and nonionic surfactant) on the penetration of beta-cypermethrin through the cabbage leaf surface were studied. The results showed that the penetration was positively correlated with both the concentration of adjuvant and the time after application, in a given range of treatment. A synergistic effect of two types of adjuvant on the penetration was found. Some physical properties of emulsions were determined. The change of the structures of the cabbage leaf surface by these adjuvants was observed from photomicrographs. The mechanism concerned with the effect of these adjuvants on the penetration of beta-cypermethrin through the cabbage leaf surface was tentatively discussed.

  20. 7 CFR 29.2278 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.2278 Section 29.2278 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... structure. The cell development of a leaf as indicated by its porosity. (See chart, § 29.2351.)...

  1. 7 CFR 29.2530 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.2530 Section 29.2530 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2530 Leaf structure. The cell development...

  2. Estimation of leaf area in tropical maize

    NARCIS (Netherlands)

    Elings, A.

    2000-01-01

    Leaf area development of six tropical maize cultivars grown in 1995 and 1996 in several tropical environments in Mexico (both favourable and moisture-and N-limited) was observed and analysed. First, the validity of a bell-shaped curve describing the area of individual leaves as a function of leaf nu

  3. Leaf out phenology in temperate forests

    Directory of Open Access Journals (Sweden)

    Caroline A. Polgar

    2013-01-01

    Full Text Available Monitoring phenology, the study of the timing of natural events, is an ancient practice that has experienced renewed relevance for scientific research interest in the wake of awareness of anthropogenic climate change. Spring onset has been occurring significantly earlier in temperate regions worldwide. Leaf out phenology has become particularly well studied is of particular interest because the emergence of leaves in the spring is extremely sensitive to temperature, and the leaf out timing of leaf out in temperate ecosystems marks the onset of the growing season and controls many essential ecosystem processes. This article reviews the current literature concerning the different methods used to study leaf out phenology, the controls on leaf out in temperate woody plants, and the effects of climate change on leaf out phenology. In addition to the traditional method of on-the-ground leaf out monitoring, new methods using remote sensing and dedicated cameras have been developed which allow scientists to track spring onset at a much larger scale than hadpreviously been possible. Further work is needed on how leaf phenology will respond to future climate change, and the implications of this for animals and other species interactions among trophic levels.

  4. 7 CFR 30.2 - Leaf tobacco.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf tobacco. 30.2 Section 30.2 Agriculture... Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO STOCKS AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of Grades § 30.2...

  5. 7 CFR 29.1029 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.1029 Section 29.1029 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 92) § 29.1029 Leaf scrap. A byproduct of stemmed and unstemmed tobacco....

  6. 7 CFR 29.2277 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.2277 Section 29.2277 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed tobacco and...

  7. Wood and leaf anatomy of Opiliaceae

    NARCIS (Netherlands)

    Koek-Noorman, J.; Rijckevorsel, v. P.

    1983-01-01

    The wood and leaf anatomy of representatives of the 9 genera of the Opiliaceae are described in detail. It is possible to separate the genera on the base of both wood- and leaf anatomical characters. Herein the presence of cystoliths of varying shape and size is important. Some comments on the taxon

  8. Designing bioinspired superoleophobic surfaces

    OpenAIRE

    Philip S. Brown; Bharat Bhushan

    2016-01-01

    Nature provides a range of functional surfaces, for example, water-repellent or superhydrophobic surfaces, most common among them the lotus leaf. While water-repellency is widespread in nature, oil-repellency is typically limited to surfaces submerged in water, such as fish scales. To achieve oleophobicity in air, inspiration must be taken from natural structures and chemistries that are not readily available in nature need to be introduced. Researchers usually turn to fluorinated materials t...

  9. Variation in light absorption properties of mentha aquatica L. as a function of leaf form: Implications for plant growth

    DEFF Research Database (Denmark)

    Enriquez, Susana; Jensen, Kaj Sand

    2008-01-01

    area increased. This relationship indicates that dispersive samples, such as leaves, although efficient light traps, can also be affected by the "package effect." Mentha aquatica leaves, by expanding their biomass (increased specific leaf area [SLA]), improve their light absorption efficiency per unit......To understand the association between leaf form and leaf optical properties, we examined light absorption variations in the leaves of Mentha aquatica L., an amphibious freshwater macrophyte. Specific absorption of leaves of M. aquatica showed a 7.5-fold variation, decreasing as pigment per unit...... photon may result in a reduction in the specific plant growth rate (RGR). Understanding the association between leaf form and the ability of leaf biomass to absorb light provides a mechanistic explanation for the empirical relationship found repeatedly in the literature between RGR and SLA. Our results...

  10. Inferring climate from angiosperm leaf venation networks.

    Science.gov (United States)

    Blonder, Benjamin; Enquist, Brian J

    2014-10-01

    Leaf venation networks provide an integrative linkage between plant form, function and climate niche, because leaf water transport underlies variation in plant performance. Here, we develop theory based on leaf physiology that uses community-mean vein density to predict growing season temperature and atmospheric CO2 concentration. The key assumption is that leaf water supply is matched to water demand in the local environment. We test model predictions using leaves from 17 temperate and tropical sites that span broad climatic gradients. We find quantitative agreement between predicted and observed climate values. We also highlight additional leaf traits that may improve predictions. Our study provides a novel approach for understanding the functional linkages between functional traits and climate that may improve the reconstruction of paleoclimate from fossil assemblages.

  11. Designing bioinspired superoleophobic surfaces

    Science.gov (United States)

    Brown, Philip S.; Bhushan, Bharat

    2016-01-01

    Nature provides a range of functional surfaces, for example, water-repellent or superhydrophobic surfaces, most common among them the lotus leaf. While water-repellency is widespread in nature, oil-repellency is typically limited to surfaces submerged in water, such as fish scales. To achieve oleophobicity in air, inspiration must be taken from natural structures and chemistries that are not readily available in nature need to be introduced. Researchers usually turn to fluorinated materials to provide the low surface energy that, when combined with bioinspired surface topography, is the key to unlocking oil-repellency. This review presents the state-of-the-art in the fabrication of superoleophobic surfaces.

  12. Nanoparticles affect PCR primarily via surface interactions with PCR components: using amino-modified silica-coated magnetic nanoparticles as a main model

    Science.gov (United States)

    Nanomaterials have been widely reported to affect the polymerase chain reaction (PCR). However, many studies in which these effects were observed were not comprehensive, and many of the proposed mechanisms have been primarily speculative. In this work, we used amino-modified silica-coated magnetic n...

  13. The impact of alkali pretreatment and post-pretreatment conditioning on the surface properties of rice straw affecting cellulose accessibility to cellulases.

    Science.gov (United States)

    Karuna, Nardrapee; Zhang, Lu; Walton, Jeffrey H; Couturier, Marie; Oztop, Mecit H; Master, Emma R; McCarthy, Michael J; Jeoh, Tina

    2014-09-01

    Rice straw was pretreated with sodium hydroxide and subsequently conditioned to reduce the pH to 5-6 by either: (1) extensive water washing or (2) acidification with hydrochloric acid then water washing. Alkali pretreatment improved the enzymatic digestibility of rice straw by increasing the cellulose accessibility to cellulases. However, acidification after pretreatment reversed the gains in cellulose accessibility to cellulases and enzymatic digestibility due to precipitation of solubilized compounds. Surface composition analyses by ToF-SIMS confirmed a reduction in surface lignin by pretreatment and water washing, and suggested that acidification precipitated a chemically modified form of lignin on the surfaces of rice straw. The spin-spin relaxation times (T2) of the samples indicated increased porosity in alkali pretreated rice straw. The acidified pretreated rice straw had reduced amounts of water in the longer T2 proton pools associated with water in the pores of the biomass likely due to back-filling by the precipitated components.

  14. Effects of mutations in the Arabidopsis Cold Shock Domain Protein 3 (AtCSP3) gene on leaf cell expansion.

    Science.gov (United States)

    Yang, Yongil; Karlson, Dale

    2012-08-01

    The cold shock domain is among the most evolutionarily conserved nucleic acid binding domains from prokaryotes to higher eukaryotes, including plants. Although eukaryotic cold shock domain proteins have been extensively studied as transcriptional and post-transcriptional regulators during various developmental processes, their functional roles in plants remains poorly understood. In this study, AtCSP3 (At2g17870), which is one of four Arabidopsis thaliana c old s hock domain proteins (AtCSPs), was functionally characterized. Quantitative RT-PCR analysis confirmed high expression of AtCSP3 in reproductive and meristematic tissues. A homozygous atcsp3 loss-of-function mutant exhibits an overall reduced seedling size, stunted and orbicular rosette leaves, reduced petiole length, and curled leaf blades. Palisade mesophyll cells are smaller and more circular in atcsp3 leaves. Cell size analysis indicated that the reduced size of the circular mesophyll cells appears to be generated by a reduction of cell length along the leaf-length axis, resulting in an orbicular leaf shape. It was also determined that leaf cell expansion is impaired for lateral leaf development in the atcsp3 loss-of-function mutant, but leaf cell proliferation is not affected. AtCSP3 loss-of-function resulted in a dramatic reduction of LNG1 transcript, a gene that is involved in two-dimensional leaf polarity regulation. Transient subcellular localization of AtCSP3 in onion epidermal cells confirmed a nucleocytoplasmic localization pattern. Collectively, these data suggest that AtCSP3 is functionally linked to the regulation of leaf length by affecting LNG1 transcript accumulation during leaf development. A putative function of AtCSP3 as an RNA binding protein is also discussed in relation to leaf development.

  15. Superhydrophobicity in perfection: the outstanding properties of the lotus leaf

    Directory of Open Access Journals (Sweden)

    Hans J. Ensikat

    2011-03-01

    Full Text Available Lotus leaves have become an icon for superhydrophobicity and self-cleaning surfaces, and have led to the concept of the ‘Lotus effect’. Although many other plants have superhydrophobic surfaces with almost similar contact angles, the lotus shows better stability and perfection of its water repellency. Here, we compare the relevant properties such as the micro- and nano-structure, the chemical composition of the waxes and the mechanical properties of lotus with its competitors. It soon becomes obvious that the upper epidermis of the lotus leaf has developed some unrivaled optimizations. The extraordinary shape and the density of the papillae are the basis for the extremely reduced contact area between surface and water drops. The exceptional dense layer of very small epicuticular wax tubules is a result of their unique chemical composition. The mechanical robustness of the papillae and the wax tubules reduce damage and are the basis for the perfection and durability of the water repellency. A reason for the optimization, particularly of the upper side of the lotus leaf, can be deduced from the fact that the stomata are located in the upper epidermis. Here, the impact of rain and contamination is higher than on the lower epidermis. The lotus plant has successfully developed an excellent protection for this delicate epistomatic surface of its leaves.

  16. Insights into the differences in leaf functional traits of heterophyllous Syringa oblata under different light intensities

    Institute of Scientific and Technical Information of China (English)

    Hongguang Xiao; Congyan Wang; Jun Liu; Lei Wang; Daolin Du

    2015-01-01

    Many plants exhibit heterophylly; the spatially and temporally remarkable ontogenetic differences in leaf morphology may play an adaptative role in their success under diverse habitats. Thus, this study aimed to gain insights into differences in leaf functional traits of heterophyllous Syringa oblata Lindl., which has been widely used as an ornamental tree around the world under different light intensities in East China. No significant differences existed in specific leaf area (SLA) between lanceolate-and heart-shaped leaves. Differ-ences in the investment per unit of light capture surface area deployed between lanceolate-and heart-shaped leaves may be not obvious. This may be attributing to the fact that single leaf wet and dry weight of heart-shaped leaves were significantly higher than those of lanceolate leaves but leaf length and leaf thickness of heart-shaped leaves were significantly lower than those of lanceolate leaves. The SLA of shade trees was sig-nificantly higher than that of sun trees. The investment per unit of light capture surface of shade trees was lower than that of sun trees, making it possible to increase light capture and use efficiency in low-light environments. The phenotypic plas-ticity of most leaf functional traits of lanceolate leaves was higher than those of heart-shaped leaves because the former is the juvenile and the latter is the adult leaf shape during the process of phylogenetic development of S. oblate. The higher range of phenotypic plasticity of leaf thickness and leaf moisture for sun trees may be beneficial to obtain a more efficient control of water loss and nutrient deprivation in high-light environments, and the lower range of phenotypic plas-ticity of single leaf wet and dry weight, and SLA for shade trees may gain an advantage to increase resource (especially light) capture and use efficiency in low-light environments. In brief, the successfully ecological strategy of plants is to find an optimal mode for the trade

  17. Leaf waxes in litter and topsoils along a European transect

    Science.gov (United States)

    Schäfer, Imke K.; Lanny, Verena; Franke, Jörg; Eglinton, Timothy I.; Zech, Michael; Vysloužilová, Barbora; Zech, Roland

    2016-10-01

    Lipid biomarkers are increasingly used to reconstruct past environmental and climate conditions. Leaf-wax-derived long-chain n-alkanes and n-alkanoic acids may have great potential for reconstructing past changes in vegetation, but the factors that affect the leaf wax distribution in fresh plant material, as well as in soils and sediments, are not yet fully understood and need further research. We systematically investigated the influence of vegetation and soil depth on leaf waxes in litter and topsoils along a European transect. The deciduous forest sites are often dominated by the n-C27 alkane and n-C28 alkanoic acid. Conifers produce few n-alkanes but show high abundances of the C24 n-alkanoic acid. Grasslands are characterized by relatively high amounts of C31 and C33 n-alkanes and C32 and C34 n-alkanoic acids. Chain length ratios thus may allow for distinguishing between different vegetation types, but caution must be exercised given the large species-specific variability in chain length patterns. An updated endmember model with the new n-alkane ratio (n-C31 + n-C33) / (n-C27 + n-C31 + n-C33) is provided to illustrate, and tentatively account for, degradation effects on n-alkanes.

  18. Applicability of non-destructive substitutes for leaf area in different stands of Norway spruce (Picea abies L. Karst.) focusing on traditional forest crown measures.

    Science.gov (United States)

    Laubhann, Daniel; Eckmüllner, Otto; Sterba, Hubert

    2010-09-30

    Since individual tree leaf area is an important measure for productivity as well as for site occupancy, it is of high interest in many studies about forest growth. The exact determination of leaf area is nearly impossible. Thus, a common way to get information about leaf area is to use substitutes. These substitutes are often variables which are collected in a destructive way which is not feasible for long term studies. Therefore, this study aimed at testing the applicability of using substitutes for leaf area which could be collected in a non-destructive way, namely crown surface area and crown projection area. In 8 stands of Norway spruce (Picea abies L. Karst.), divided into three age classes and two thinning treatments, a total of 156 trees were felled in order to test the relationship between leaf area and crown surface area and crown projection area, respectively. Individual tree leaf area of the felled sample trees was estimated by 3P-branch sampling with an accuracy of ±10%. Crown projection area and crown surface area were compared with other, more commonly used, but destructive predictors of leaf area, namely sapwood area at different heights on the bole. Our investigations confirmed findings of several studies that sapwood area is the most precise measure for leaf area because of the high correlation between sapwood area and the leaf area. But behind sapwood area at crown base and sapwood area at three tenth of the tree height the predictive ability of crown surface area was ranked third and even better than that of sapwood area at breast height (R(2) = 0.656 compared with 0.600). Within the stands leaf area is proportional to crown surface area. Using the pooled data of all stands a mixed model approach showed that additionally to crown surface area dominant height and diameter at breast height (dbh) improved the leaf area estimates. Thus, taking dominant height and dbh into account, crown surface area can be recommended for estimating the leaf area

  19. Aluminum solubility and mobility in relation to organic carbon in surface soils affected by six tree species of the northeastern United States

    NARCIS (Netherlands)

    Dijkstra, F.A.; Fitzhugh, R.D.

    2003-01-01

    We compared Al solubility and mobility in surface soils among six tree species (sugar maple [Acer saccharum], white ash [Fraxinus americana], red maple [Acer rubrum, L.], American beech [Fagus grandifolia, Ehrh.], red oak [Quercus rubra, L.], and hemlock [Tsuga canadensis, Carr.]) in a mixed hardwoo

  20. Predicting green leaf proportion in ungrazed kleingrass (Panicum coloratum L. in the semiarid Pampas Region of Argentina

    Directory of Open Access Journals (Sweden)

    Carlos M Ferri

    2013-06-01

    Full Text Available Green leaf proportion is an important factor affecting nutritive value, ingestive behavior and forage intake. Determination of green leaf proportion by hand separation of plant samples is time consuming and expensive. The aim of this work was to establish whether a stable relationship exists between the proportion of green leaf blade and total mass of harvestable forage in ungrazed kleingrass (Panicum coloratum L. cv. Verde. The study was carried out during four consecutive growing seasons in an established pasture of kleingrass. During two growing seasons, 90 kg N ha-1 was applied. Forage samples were collected at biweekly intervals and separated into leaf blades, stems (inclusive of leaf sheaths, and senescent material. Regression analysis indicated a consistent relationship (y = 0.70x-0.41, R² = 0.84, P< 0.001, n = 180 between the proportion of green leaf blade and total mass of harvestable forage in ungrazed kleingrass, even under varying environmental conditions of rainfall and N availability. Thus, total harvestable forage might be used to predict the green leaf proportion of kleingrass in contrasting environments, and used as an easy-to-measure indicator of green leaf proportion that would permit a balance of forage quality and quantity in kleingrass.

  1. Genetic control of leaf-blade morphogenesis by the INSECATUS gene in Pisum sativum

    Indian Academy of Sciences (India)

    Sushil Kumar; Swati Chaudhary; Vishakha Sharma; Renu Kumari; Raghvendra Kumar Mishra; Arvind Kumar; Debjani Roy Choudhury; Ruchi Jha; Anupama Priyadarshini; Arun Kumar

    2010-08-01

    To understand the role of INSECATUS (INS) gene in pea, the leaf blades of wild-type, ins mutant and seven other genotypes, constructed by recombining ins with uni-tac, af, tl and mfp gene mutations, were quantitatively compared. The ins was inherited as a recessive mutant allele and expressed its phenotype in proximal leaflets of full size leaf blades. In ins leaflets, the midvein development was arrested in distal domain and a cleft was formed in lamina above this point. There was change in the identity of ins leaflets such that the intercalary interrupted midvein bore a leaf blade. Such adventitious blades in ins, ins tl and ins tl mfp were like the distal segment of respective main leaf blade. The ins phenotype was not seen in ins af and ins af uni-tac genotypes. There was epistasis of uni-tac over ins. The ins, tl and mfp mutations interacted synergistically to produce highly pronounced ins phenotype in the ins tl mfp triple mutant. The role(s) of INS in leaf-blade organogenesis are: positive regulation of vascular patterning in leaflets, repression of UNI activity in leaflet primordia for ectopic growth and in leaf-blade primordium for indeterminate growth of rachis, delimitation of proximal leaflet domain and together with TL and MFP homeostasis for meristematic activity in leaflet primordia. The variant apically bifid shape of the affected ins leaflets demonstrated that the leaflet shape is dependent on the venation pattern.

  2. Leaf-on canopy closure in broadleaf deciduous forests predicted during winter

    Science.gov (United States)

    Twedt, Daniel J.; Ayala, Andrea J.; Shickel, Madeline R.

    2015-01-01

    Forest canopy influences light transmittance, which in turn affects tree regeneration and survival, thereby having an impact on forest composition and habitat conditions for wildlife. Because leaf area is the primary impediment to light penetration, quantitative estimates of canopy closure are normally made during summer. Studies of forest structure and wildlife habitat that occur during winter, when deciduous trees have shed their leaves, may inaccurately estimate canopy closure. We estimated percent canopy closure during both summer (leaf-on) and winter (leaf-off) in broadleaf deciduous forests in Mississippi and Louisiana using gap light analysis of hemispherical photographs that were obtained during repeat visits to the same locations within bottomland and mesic upland hardwood forests and hardwood plantation forests. We used mixed-model linear regression to predict leaf-on canopy closure from measurements of leaf-off canopy closure, basal area, stem density, and tree height. Competing predictive models all included leaf-off canopy closure (relative importance = 0.93), whereas basal area and stem density, more traditional predictors of canopy closure, had relative model importance of ≤ 0.51.

  3. Multiple components are integrated to determine leaf complexity in Lotus japonicus.

    Science.gov (United States)

    Wang, Zhenhua; Chen, Jianghua; Weng, Lin; Li, Xin; Cao, Xianglin; Hu, Xiaohe; Luo, Da; Yang, Jun

    2013-05-01

    Transcription factors and phytohormones have been reported to play crucial roles to regulate leaf complexity among plant species. Using the compound-leafed species Lotus japonicus, a model legume plant with five visible leaflets, we characterized four independent mutants with reduced leaf complexity, proliferating floral meristem (pfm), proliferating floral organ-2 (pfo-2), fused leaflets1 (ful1) and umbrella leaflets (uml), which were further identified as loss-of-function mutants of Arabidopsis orthologs LEAFY (LFY), UNUSUAL FLORAL ORGANS (UFO), CUP-SHAPED COTYLEDON 2 (CUC2) and PIN-FORMED 1 (PIN1), respectively. Comparing the leaf development of wild-type and mutants by a scanning electron microscopy approach, leaflet initiation and/or dissection were found to be affected in these mutants. Expression and phenotype analysis indicated that PFM/LjLFY and PFO/LjUFO determined the basipetal leaflet initiation manner in L. japonicus. Genetic analysis of ful1 and uml mutants and their double mutants revealed that the CUC2-like gene and auxin pathway also participated in leaflet dissection in L. japonicus, and their functions might influence cytokinin biogenesis directly or indirectly. Our results here suggest that multiple genes were interplayed and played conserved functions in controlling leaf complexity during compound leaf development in L. japonicus.

  4. Leaf Structure and Taxonomy of Petunia and Calibrachoa (Solanaceae

    Directory of Open Access Journals (Sweden)

    Claudia dos Reis

    2002-03-01

    Full Text Available We studied the leaf anatomy of sixteen species of Calibrachoa and eight species of Petunia. In Calibrachoa leaves, the vascular bundles sheath (endodermis was formed by parenchymatous developed cells, different from those of the mesophyll. In Petunia, this sheath did not show a marked morphological differentiation. The Calibrachoa leaves could be separated according to the type of leaf margins, the distribution of the stomata on leaf surfaces, the organization of the mesophyll and the morphology of the trichomes. Based on these results, an indented dichotomous identification key was elaborated for the species of the genus Calibrachoa.Foram estudados, sob o ponto de vista anatômico, os limbos foliares de dezesseis espécies de Calibrachoa Llav. & Lex. e de oito espécies de Petunia Juss. (Solanaceae. Em Calibrachoa, a bainha que envolve os feixes vasculares (endoderme é formada por células desenvolvidas e distintas das do mesofilo. Em Petunia, esta bainha não apresenta diferenciação morfológica marcante. As folhas das espécies de Calibrachoa foram separadas entre si levando-se em conta a distribuição dos estômatos nas faces foliares, a organização do mesofilo, o tipo de bordo e a morfologia dos tricomas. Com base nesses resultados, foi elaborada uma chave dicotômica indentada de identificação para as espécies do gênero Calibrachoa.

  5. Lifting Entry & Atmospheric Flight (LEAF) Applications at Solar System Bodies.

    Science.gov (United States)

    Lee, G.; Sen, B.; Polidan, R. S.

    2015-12-01

    Introduction: Northrop Grumman and L'Garde have continued the development of a hypersonic entry, maneuverable platform capable of performing long-duration (months to a year) in situ and remote measurements at any solar system body that possesses an atmosphere. The Lifting Entry & Atmospheric Flight (LEAF) family of vehicles achieve this capability by using a semi-buoyant, ultra-low ballistic coefficient vehicle whose lifting entry allows it to enter the atmosphere without an aeroshell. In this presentation, we discuss the application of the LEAF system at various solar system bodies: Venus, Titan, Mars, and Earth. We present the key differences in platform design as well as operational differences required by the various target environments. The Venus implementation includes propulsive capability to reach higher altitudes during the day and achieves full buoyancy in the "habitable layers" of Venus' atmosphere at night. Titan also offers an attractive operating environment, allowing LEAF designs that can target low, medium, or high altitude operations, also with propulsive capabilities to roam within each altitude regime. The Mars version is a glider that descends gradually, allowing targeted delivery of payloads to the surface. Finally, an Earth version could remain in orbit in a stowed state until activated, allowing rapid response type deployments to any region of the globe.

  6. Simulation of leaf area index and biomass at landscape scale

    Institute of Scientific and Technical Information of China (English)

    ZHANGNa; YUGuirui; YUZhenliang; ZHAOShidong

    2003-01-01

    The method for simulating the temporal and spatial distribution patterns of leaf area index (LAI) and biomass at landscape scale using remote sensing images and surface data was discussed in this paper,The procedure was:(1) annual maximum normalized difference vegetation index (NDVI) over the landscape was calculated from TM images;(2) the relationship model between NDVI and LAI was built and annual maximum LAI over the landscape was simulated;(3) the relationship models between LAI and biomass were built and annual branch ,stem ,root and maximum leaf biomass over the landscape were simulated;(4) spatial distribution patterns of leaf biomass and LAI in different periods all the year round were obtained.The simulation was based on spatial analysis module GRID in ArcoInfo software ,The method is laso a kind of scaling method from patch scale to landscape scale ,A case study of Changbai Mountain Nature Reserve was dissertated ,Aalysis and primary validation were carried out to the simulated LAI and biomass for the major vegetation types in the Changbai Mountain in 1995.

  7. Affective Urbanism

    DEFF Research Database (Denmark)

    Samson, Kristine

    Urban design and architecture are increasingly used as material and affective strategies for setting the scene, for manipulation and the production of urban life: The orchestration of atmospheres, the framing and staging of urban actions, the programming for contemplation, involvement, play, expe...... affects can be choreographed and designed intentionally or whether it arises from unpredictable circumstances within urbanity itself....

  8. Affective Maps

    DEFF Research Database (Denmark)

    Salovaara-Moring, Inka

    of environmental knowledge production. It uses InfoAmazonia, the databased platform on Amazon rainforests, as an example of affective geo-visualization within information mapping that enhances embodiment in the experience of the information. Amazonia is defined as a digitally created affective (map)space within...

  9. 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

  10. In Vivo Monitoring on Growth and Spread of Gray Leaf Spot Disease in Capsicum annuum Leaf Using Spectral Domain Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Naresh Kumar Ravichandran

    2016-01-01

    Full Text Available We have demonstrated the application of optical coherence tomography (OCT in diagnosis of growth and spread of the gray leaf spot disease in Capsicum annuum leaf caused by the fungus Stemphylium lycopersici. Using 2D cross-sectional and 3D volumetric images of OCT, in vivo study of layer differences between fungus infected leaves and healthy leaves was observed with distinctive features. We observed that the internal layers of the disease-affected parts of the leaf seem to merge forming a single thick layer. The obtained OCT results verify the noninvasive diagnosis ability of fungal growth and spread in Capsicum annuum leaves and the applicability of this methodology for other plant diseases.

  11. Titan LEAF: A Sky Rover Granting Targeted Access to Titan's Lakes and Plains

    Science.gov (United States)

    Ross, Floyd; Lee, Greg; Sokol, Daniel; Goldman, Benjamin; Bolisay, Linden

    2016-10-01

    Northrop Grumman, in collaboration with L'Garde Inc. and Global Aerospace Corporation (GAC), has been developing the Titan Lifting Entry Atmospheric Flight (T-LEAF) sky rover to roam the atmosphere and observe at close quarters the lakes and plains of Titan. T-LEAF also supports surface exploration and science by providing precision delivery of in situ instruments to the surface.T-LEAF is a maneuverable, buoyant air vehicle. Its aerodynamic shape provides its maneuverability, and its internal helium envelope reduces propulsion power requirements and also the risk of crashing. Because of these features, T-LEAF is not restricted to following prevailing wind patterns. This freedom of mobility allows it be commanded to follow the shorelines of Titan's methane lakes, for example, or to target very specific surface locations.T-LEAF utilizes a variable power propulsion system, from high power at ~200W to low power at ~50W. High power mode uses the propellers and control surfaces for additional mobility and maneuverability. It also allows the vehicle to hover over specific locations for long duration surface observations. Low power mode utilizes GAC's Titan Winged Aerobot (TWA) concept, currently being developed with NASA funding, which achieves guided flight without the use of propellers or control surfaces. Although slower than high powered flight, this mode grants increased power to science instruments while still maintaining control over direction of travel.Additionally, T-LEAF is its own entry vehicle, with its leading edges protected by flexible thermal protection system (f-TPS) materials already being tested by NASA's Hypersonic Inflatable Aerodynamic Decelerator (HIAD) group. This f-TPS technology allows T-LEAF to inflate in space, like HIAD, and then enter the atmosphere fully deployed. This approach accommodates entry velocities from as low as ~1.8 km/s if entering from Titan orbit, up to ~6 km/s if entering directly from Saturn orbit, like the Huygens probe

  12. Modelling coffee leaf rust risk in Colombia with climate reanalysis data

    Science.gov (United States)

    Castillo, Ángela Delgado; Gurr, Sarah J.

    2016-01-01

    Many fungal plant diseases are strongly controlled by weather, and global climate change is thus likely to have affected fungal pathogen distributions and impacts. Modelling the response of plant diseases to climate change is hampered by the difficulty of estimating pathogen-relevant microclimatic variables from standard meteorological data. The availability of increasingly sophisticated high-resolution climate reanalyses may help overcome this challenge. We illustrate the use of climate reanalyses by testing the hypothesis that climate change increased the likelihood of the 2008–2011 outbreak of Coffee Leaf Rust (CLR, Hemileia vastatrix) in Colombia. We develop a model of germination and infection risk, and drive this model using estimates of leaf wetness duration and canopy temperature from the Japanese 55-Year Reanalysis (JRA-55). We model germination and infection as Weibull functions with different temperature optima, based upon existing experimental data. We find no evidence for an overall trend in disease risk in coffee-growing regions of Colombia from 1990 to 2015, therefore, we reject the climate change hypothesis. There was a significant elevation in predicted CLR infection risk from 2008 to 2011 compared with other years. JRA-55 data suggest a decrease in canopy surface water after 2008, which may have helped terminate the outbreak. The spatial resolution and accuracy of climate reanalyses are continually improving, increasing their utility for biological modelling. Confronting disease models with data requires not only accurate climate data, but also disease observations at high spatio-temporal resolution. Investment in monitoring, storage and accessibility of plant disease observation data are needed to match the quality of the climate data now available. This article is part of the themed issue ‘Tackling emerging fungal threats to animal health, food security and ecosystem resilience’. PMID:28080984

  13. Global Climatic Controls On Leaf Size

    Science.gov (United States)

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

    2015-12-01

    Since the 1890s it's been known that the wet tropics harbour plants with exceptionally large leaves. Yet the observed latitudinal gradient of leaf size has never been fully explained: it is still unclear which aspects of climate are most important for understanding geographic trends in leaf size, a trait that varies many thousand-fold among species. The key is the leaf-to-air temperature difference, which depends on the balance of energy inputs (irradiance) and outputs (transpirational cooling, losses to the night sky). Smaller leaves track air temperatures more closely than larger leaves. Widely cited optimality-based theories predict an advantage for smaller leaves in dry environments, where transpiration is restricted, but are silent on the latitudinal gradient. We aimed to characterize and explain the worldwide pattern of leaf size. Across 7900 species from 651 sites, here we show that: large-leaved species predominate in wet, hot, sunny environments; smaller-leaved species typify hot, sunny environments only when arid; small leaves are required to avoid freezing in high latitudes and at high elevation, and to avoid overheating in dry environments. This simple pattern was unclear in earlier, more limited analyses. We present a simple but robust, fresh approach to energy-balance modelling for both day-time and night-time leaf-to-air temperature differences, and thus risk of overheating and of frost damage. Our analysis shows night-chilling is important as well as day-heating, and simplifies leaf temperature modelling. It provides both a framework for modelling leaf size constraints, and a solution to one of the oldest conundrums in ecology. Although the path forward is not yet fully clear, because of its role in controlling leaf temperatures we suggest that climate-related leaf size constraints could usefully feature in the next generation of land ecosystem models.

  14. Leaf dynamics and profitability in wild strawberries.

    Science.gov (United States)

    Jurik, Thomas W; Chabot, Brian F

    1986-05-01

    Leaf dynamics and carbon gain were evaluated for two species of wild strawberry, Fragaria virginiana and F. vesca. Five populations on sites representing a gradient of successional regrowth near Ithaca, N.Y., U.S.A., were studied for two or three years each. A computer-based model of plant growth and CO2 exchange combined field studies of leaf biomass dynamics with previously-determined gas exchange rates to estimate carbon balances of leaves and whole plants in different environments.Leaves were produced throughout the growing season, although there was usually a decline in rate of leaf-production in mid-summer. Leaves produced in late spring had the largest area and longest lifespan (except for overwintering leaves produced in the fall). Specific Leaf Weight (SLW) varied little with time of leaf production, but differed greatly among populations; SLW increased with amount of light received in each habitat. The population in the most open habitat had the least seasonal variation in all leaf characters. F. vesca produced lighter, longer-lived leaves than F. virginiana.Simulations showed that age had the largest effect on leaf carbon gain in high-light environments; water stress and temperature had lesser effects. Leaf carbon gain in lowlight environments was relatively unaffected by age and environmental factors other than light. Leaves in high-light environments had the greatest lifetime profit and the greatest ratio of profit to cost. Increasing lifespan by 1/3 increased profit by 80% in low-light leaves and 50% in high-light leaves. Increasing the number of days during which the leaf had the potential to exhibit high photosynthetic rate in response to high light led to little change in profit of low-light leaves while increasing profit of high-light leaves by 49%.

  15. Controls on the D/H ratios of plant leaf waxes in an arid ecosystem

    Science.gov (United States)

    Feakins, Sarah J.; Sessions, Alex L.

    2010-04-01

    The extent to which leaf water D-enrichment (transpiration) and soil water D-enrichment (evaporation) affect the D/H ratio of plant leaf waxes remains a contentious issue, with important implications for paleohydrologic reconstructions. In this study we measure δD values of precipitation ( δD p), groundwater ( δD gw), plant xylem water ( δD xw) and leaf water ( δD lw) to understand their impact on the δD values of plant leaf wax n-alkanes ( δD wax) in an arid ecosystem. Our survey includes multiple species at four sites across an aridity gradient (80-30% relative humidity) in southern California. We find that many species take up groundwater or precipitation without significant fractionation. D-enriched soil water is a minor source even in species known to perform and utilize waters from hydraulic lift, such as Larrea tridentata (+10‰). Measurements of leaf water isotopic composition demonstrate that transpiration is an important mechanism for D-enrichment of leaf waters (+74 ± 20‰, 1 σ), resulting in the smallest net fractionation yet reported between source water and leaf waxes ( L. tridentata -41‰; multi-species mean value is -94 ± 21‰, 1 σ). We find little change in leaf water D-enrichment or net fractionation across the climatic gradient sampled by our study, suggesting that a net fractionation of ca. -90‰ may be appropriate for paleohydrologic reconstructions in semi-arid to arid environments. Large interspecies offsets in net fractionations (1 σ = 21‰) are potentially troublesome, given the observed floristic diversity and the likelihood of species assemblage changes with climate shifts.

  16. The important role of surface ligand on CdSe/CdS core/shell nanocrystals in affecting the efficiency of H2 photogeneration from water

    Science.gov (United States)

    Wang, Ping; Zhang, Jie; He, Haili; Xu, Xiaolong; Jin, Yongdong

    2015-03-01

    The use of colloidal semiconductor nanocrystals (NCs), especially those with a core/shell structure, for photocatalytic hydrogen (H2) production from water is currently one of the hottest research fields. Although the ligand on the semiconductor NC surface is crucial to the optical and optoelectronic properties of the NC, the study of the ligand effect on the photocatalytic activity of H2 generation is rarely reported. Herein, we employ nearly monodispersed CdSe/CdS core/shell NCs as a model photocatalytic system, and three kinds of ligands with different numbers of functional thiol groups (i.e., poly(acrylic acid), 3-mercaptopropionic acid and 2,3-dimercaptosuccinic acid) are selected as the ligands to investigate the effect of ligand on the efficiency of H2 photogeneration. The results show that the H2 photogeneration efficiency is highly dependent on the surface ligand of the NCs, and it increases with the increase of the number of the functional thiol groups in the ligand, and correspondingly, the photoluminescence intensity and average fluorescence lifetime, which are measured by steady state and time-resolved fluorescence measurements, are decreased. The surface trap-related charge separation efficiency, which is mediated by surface coating with different ligands, is supposed to cause the distinct ligand-dependent performance in the H2 evolution.The use of colloidal semiconductor nanocrystals (NCs), especially those with a core/shell structure, for photocatalytic hydrogen (H2) production from water is currently one of the hottest research fields. Although the ligand on the semiconductor NC surface is crucial to the optical and optoelectronic properties of the NC, the study of the ligand effect on the photocatalytic activity of H2 generation is rarely reported. Herein, we employ nearly monodispersed CdSe/CdS core/shell NCs as a model photocatalytic system, and three kinds of ligands with different numbers of functional thiol groups (i.e., poly(acrylic acid), 3

  17. Leaf isoprene emission in a subarctic wetland sedge community

    Science.gov (United States)

    Ekberg, A.; Arneth, A.; Hakola, H.; Hayward, S.; Holst, T.

    2008-12-01

    High latitude wetlands play an important role for the surface-atmosphere exchange of carbon dioxide (CO2) and methane (CH4), but fluxes of biogenic volatile organic compounds (BVOC) in these ecosystems have to date not been extensively studied. This is despite BVOC representing a measurable proportion of the total gaseous C fluxes at northern locations and in the face of the high temperature sensitivity of these systems that requires a much improved process understanding to interpret and project possible changes in response to climate warming. We measured emission of isoprene and photosynthetic gas exchange over two growing seasons (2005-2006) in a subarctic wetland in northern Sweden with the objective to identify the physiological and environmental controls of these fluxes on the leaf scale. The sedge species Eriophorum angustifolium and Carex rostrata were both emitters of isoprene, and springtime emissions were first detected after an accumulated diurnal mean temperature above 0°C of about 100 degree days. Maximum measured growing season standardized (basal) emission rates (20°C, 1000 μmol m-2 s-1) were 1075 (2005) and 1118 (2006) μg C m-2 (leaf area) h-1 in E. angustifolium, and 489 (2005) and 396 (2006) μg C m-2 h-1 in C. rostrata. Over the growing season, basal isoprene emission varied in response to the temperature history of the last 48 h. Seasonal basal isoprene emission rates decreased also with leaf nitrogen (N), which may be explained by the typical growth and resource allocation pattern of clonal sedges as the leaves age. The observations were used to model emissions over the growing season, accounting for effects of temperature history, links to leaf assimilation rate and the light and temperature dependencies of the cold-adapted sedges.

  18. Leaf breakdown in a natural open tropical stream

    Directory of Open Access Journals (Sweden)

    Elisa A.C.C. Alvim

    2014-09-01

    Full Text Available Leaf breakdown is a primary process of nutrient cycling and energy flow, contributing to the functioning of aquatic ecosystems. In the present study, leaves of Baccharis platypoda and Coccoloba cereifera were incubated in a high-altitude stream in a rupestrian field. Two hypotheses were tested: i intrinsic factors (quality of detritus are more important than extrinsic factors (decomposer communities in decomposition; and ii low detritus quality hinders microbial colonization, thereby altering the composition and structure of the associated invertebrate community and slowing leaf breakdown. The breakdown coefficients of B. platypoda and C. cereifera leaves were low (k = -0.0019 day-1 and k = -0.0008 day-1, respectively and the proportions of structural compounds were high, delaying the remobilization of energy and nutrients into the aquatic ecosystem. Fungal biomass was higher at the end of the experiment, suggesting favorable conditions for colonization. The densities of invertebrates associated with the detritus increased coincident with the peak concentration of ergosterol, with the trophic groups collector-gatherer and scraper having the highest densities. The distribution of these groups was likely related to the growth of biofilm on the surface of the litters. As described for tropical streams, shredders had the lowest densities of any invertebrate group, suggesting a reduced participation of these invertebrates in leaf processing. The results suggest that slow decomposing species are important to both invertebrates and microorganisms as substrates and sources of particulate organic matter. The low palatability and nutritional quality of the detritus in the present study, associated with low dissolved nutrient concentrations in water, delayed the leaf conditioning process by microorganisms. Decomposition rates and invertebrate participation were reduced as a result, leading to major physical decomposition. Headwater tropical streams have

  19. Impact of plant shoot architecture on leaf cooling: a coupled heat and mass transfer model.

    Science.gov (United States)

    Bridge, L J; Franklin, K A; Homer, M E

    2013-08-01

    Plants display a range of striking architectural adaptations when grown at elevated temperatures. In the model plant Arabidopsis thaliana, these include elongation of petioles, and increased petiole and leaf angles from the soil surface. The potential physiological significance of these architectural changes remains speculative. We address this issue computationally by formulating a mathematical model and performing numerical simulations, testing the hypothesis that elongated and elevated plant configurations may reflect a leaf-cooling strategy. This sets in place a new basic model of plant water use and interaction with the surrounding air, which couples heat and mass transfer within a plant to water vapour diffusion in the air, using a transpiration term that depends on saturation, temperature and vapour concentration. A two-dimensional, multi-petiole shoot geometry is considered, with added leaf-blade shape detail. Our simulations show that increased petiole length and angle generally result in enhanced transpiration rates and reduced leaf temperatures in well-watered conditions. Furthermore, our computations also reveal plant configurations for which elongation may result in decreased transpiration rate owing to decreased leaf liquid saturation. We offer further qualitative and quantitative insights into the role of architectural parameters as key determinants of leaf-cooling capacity.

  20. Low-cost chlorophyll meter (LCCM): portable measuring device for leaf chlorophyll

    Science.gov (United States)

    Hutomo E. P., Evan; Adibawa, Marcelinus Alfasisurya S.; Prilianti, Kestrilia R.; Heriyanto, Heriyanto; Brotosudarmo, Tatas H. P.

    2016-11-01

    Portable leaf chlorophyll meter, named low-cost chlorophyll meter (LCCM), has been created. This device was created to help farmer determining the health condition of plant based on the greenness level of leaf surface. According to previous studies, leaf greenness with a certain amount of chlorophyll level has a direct correlation with the amount of nitrogen in the leaf that indicates health of the plant and this fact needed to provide an estimate of further measures to keep the plants healthy. Device that enables to measure the leaf color change is soil plant analysis development (SPAD) meter 502 from Konica Minolta but it is relatively expensive. To answer the need of low-cost chlorophyll scanner device, this research conducted experiment using light reflectance as the base mechanism. Reflectance system from LCCM consists of near-infrared light emitting diode (LED) and red LED as light resources and photodiode. The output from both of light resources calculated using normalized difference vegetation index (NDVI) formula as the results fetched and displayed on the smartphone application using Bluetooth communication protocol. Finally, the scanner has been made as well as the Android application named NDVI Reader. The LCCM system which has been tested on 20 sample of cassava leaf with SPAD meter as a variable control showed coefficient of determination 0.9681 and root-mean-square error (RMSE) 0.014.

  1. Leaf-closing substance in Leucaena leucocephala.

    Science.gov (United States)

    Sohtome, Yoshihiro; Tokunaga, Takashi; Ueda, Katsuhiro; Yamamura, Shosuke; Ueda, Minoru

    2002-01-01

    Potassium (2R,3R)-2,3,4-trihydroxy-2-methylbutanoate (1) was identified as a leaf-closing substance in the nyctinastic plant, Leucaena leucocephala. Compound 1 showed strong leaf-closing activity toward L. leucocephala and was not effective against other nyctinastic plants. The potassium ion was indispensable for the bioactivity of 1. Compound 1 gradually lost its bioactivity because of the exchange of the counter cation during isolation. A leaf-opening substance was also observed in the same plant.

  2. Antimicrobial activity of Tridax procumbens leaf

    Directory of Open Access Journals (Sweden)

    S.Santhosh Kumar

    2015-03-01

    Full Text Available Estimation of the antimicrobial property of Tridax procumbens’s leaf was carried out by the use of chloroform, petroleum ether, ethyl alcohol and hexaneas solvents. Leaf extract of Tridax procumbens obtained by soxhlet extractor, using the above mentioned solvents were examined against Escherichia coli, Bacillus subtilis, and Pseudomonas vulgaris. The antimicrobial activity of Tridax procumbens performed by using agarwell diffusion method showed a result showcasing an effective limit when as opposed to Pseudomonas vulgarisfor ethyl alcohol being used as solvent for extract. In conclusion Tridax procumbens leaf extract terminates most propitious source.

  3. 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...... potential, leaf turgor and stomatal conductance were highest for full irrigation (FI), followed by the deficit irrigation (DI) and non-irrigation (NI) treatments. Osmotic potential was not affected by root pruning and irrigation regimes while the xylem ABA concentration was higher in the RP compared to NP...

  4. Mercury in leaf litter in typical suburban and urban broadleaf forests in China

    Institute of Scientific and Technical Information of China (English)

    Zhenchuan Niu; Xiaoshan Zhang; Zhangwei Wang; Zhijia Ci

    2011-01-01

    To study the role of leaf litter in the mercury (Hg) cycle in suburban broadleaf forests and the distribution of Hg in urban forests,we collected leaf litter and soil from suburban evergreen and deciduous broadleaf forests and from urban forests in Beijing.The Hg concentrations in leaf litter from the suburban forests varied from 8.3 to 205.0 ng/g,with an average (avg) of (49.7 ± 36.9) ng/g.The average Hg concentration in evergreen broadleaf forest leaf litter (50.8 ± 39.4) ng/g was higher than that in deciduous broadleaf forest leaf litter (25.8 + 10.1) ng/g.The estimated Hg fluxes of leaf litter in suburban evergreen and deciduous broadleaf forests were 179.0 and 83.7 mg/(ha.yr),respectively.The Hg concentration in organic horizons (O horizons) ((263.1 + 237.2) ng/g) was higher than that in eluvial horizons (A horizons) ((83.9 + 52.0) ng/g).These results indicated that leaf litterfall plays an important role in transporting atmospheric mercury to soil in suburban forests.For urban forests in Beijing,the Hg concentrations in leaf litter