WorldWideScience

Sample records for single leaf area

  1. 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.

  2. Developing allometric equations for estimating leaf area and leaf ...

    African Journals Online (AJOL)

    Estimation of leaf area (LA) and leaf biomass (LB) is important to understand plant physiological and carbon assimilation processes, and tree growth models. The aim of this study was to develop and compare allometric equations for predicting LA and LB of Artocarpus chaplasha Roxb. taking diameter at breast height ...

  3. Barley Leaf Area and Leaf Growth Rates Are Maximized during the Pre-Anthesis Phase

    Directory of Open Access Journals (Sweden)

    Ahmad M. Alqudah

    2015-04-01

    Full Text Available Leaf developmental traits are an important component of crop breeding in small-grain cereals. Surprisingly, little is known about the genetic basis for the differences in barley (Hordeum vulgare L. leaf development. The two barley row-type classes, i.e., two- and six-rowed, show clear-cut differences in leaf development. To quantify these differences and to measure the genetic component of the phenotypic variance for the leaf developmental differences in both row-type classes we investigated 32 representative spring barley accessions (14 two- and 18 six-rowed accessions under three independent growth conditions. Leaf mass area is lower in plants grown under greenhouse (GH conditions due to fewer, smaller, and lighter leaf blades per main culm compared to pot- and soil-grown field plants. Larger and heavier leaf blades of six-rowed barley correlate with higher main culm spike grain yield, spike dry weight, and harvest index; however, smaller leaf area (LA in two-rowed barley can be attributed to more spikes, tillers, and biological yield (aboveground parts. In general, leaf growth rate was significantly higher between awn primordium and tipping stages. Moderate to very high broad-sense heritabilities (0.67–0.90 were found under all growth conditions, indicating that these traits are predominantly genetically controlled. In addition, our data suggests that GH conditions are suitable for studying leaf developmental traits. Our results also demonstrated that LA impacts single plant yield and can be reconsidered in future breeding programs. Six-rowed spike 1 (Vrs1 is the major determinate of barley row-types, the differences in leaf development between two- and six-rowed barleys may be attributed to the regulation of Vrs1 in these two classes, which needs further testing.

  4. Effects of leaf area of downy oak (Quercus pubescens Willd ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-08-18

    Aug 18, 2009 ... On the other hand, the light energy that is held by a leaf depends on the size of the leaf area (leaf surface). The measure of the leaf surface area (l.a.) is total leaf surface area of the plant (m2). The ratio between the total surface leaf area of a plant and the land area it covers (m2/ha or m2/m2) at a certain ...

  5. Is leaf dry matter content a better predictor of soil fertility than specific leaf area?

    NARCIS (Netherlands)

    Hodgson, J.G.; Montserrat-Marti, G.; Charles, M.; Jones, G.; Wilson, P.; Shipley, B.; Sharafi, M.; Cerabolini, B.E.L.; Cornelissen, J.H.C.; Band, S.R.; Bogard, A.; Castro-Diez, P.; Guerrere-Campo, J.; Palmer, C.; Peréz-Rontomé, M.C.; Carter, G.; Hynd, A.; Romo-Diez, A.; De Torres Espuny, L.; Royo Pla, F.

    2011-01-01

    Background and Aims: Specific leaf area (SLA), a key element of the 'worldwide leaf economics spectrum', is the preferred 'soft' plant trait for assessing soil fertility. SLA is a function of leaf dry matter content (LDMC) and leaf thickness (LT). The first, LDMC, defines leaf construction costs and

  6. Is leaf dry matter content a better predictor of soil fertility than specific leaf area?

    Science.gov (United States)

    Hodgson, J G; Montserrat-Martí, G; Charles, M; Jones, G; Wilson, P; Shipley, B; Sharafi, M; Cerabolini, B E L; Cornelissen, J H C; Band, S R; Bogard, A; Castro-Díez, P; Guerrero-Campo, J; Palmer, C; Pérez-Rontomé, M C; Carter, G; Hynd, A; Romo-Díez, A; de Torres Espuny, L; Royo Pla, F

    2011-11-01

    Specific leaf area (SLA), a key element of the 'worldwide leaf economics spectrum', is the preferred 'soft' plant trait for assessing soil fertility. SLA is a function of leaf dry matter content (LDMC) and leaf thickness (LT). The first, LDMC, defines leaf construction costs and can be used instead of SLA. However, LT identifies shade at its lowest extreme and succulence at its highest, and is not related to soil fertility. Why then is SLA more frequently used as a predictor of soil fertility than LDMC? SLA, LDMC and LT were measured and leaf density (LD) estimated for almost 2000 species, and the capacity of LD to predict LDMC was examined, as was the relative contribution of LDMC and LT to the expression of SLA. Subsequently, the relationships between SLA, LDMC and LT with respect to soil fertility and shade were described. Although LD is strongly related to LDMC, and LDMC and LT each contribute equally to the expression of SLA, the exact relationships differ between ecological groupings. LDMC predicts leaf nitrogen content and soil fertility but, because LT primarily varies with light intensity, SLA increases in response to both increased shade and increased fertility. Gradients of soil fertility are frequently also gradients of biomass accumulation with reduced irradiance lower in the canopy. Therefore, SLA, which includes both fertility and shade components, may often discriminate better between communities or treatments than LDMC. However, LDMC should always be the preferred trait for assessing gradients of soil fertility uncoupled from shade. Nevertheless, because leaves multitask, individual leaf traits do not necessarily exhibit exact functional equivalence between species. In consequence, rather than using a single stand-alone predictor, multivariate analyses using several leaf traits is recommended.

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

    Science.gov (United States)

    Peter B. Reich; Michael B. Walters; David S. Ellsworth; [and others; [Editor’s note: James M.. Vose is the SRS co-author for this publication.

    1998-01-01

    Based on prior evidence of coordinated multiple leaf trait scaling, the authors hypothesized that variation among species in leaf dark respiration rate (Rd) should scale with variation in traits such as leaf nitrogen (N), leaf life-span, specific leaf area (SLA), and net photosynthetic capacity (Amax). However, it is not known whether such scaling, if it exists, is...

  8. Leaf area index from litter collection: impact of specific leaf area variability within a beech stand

    International Nuclear Information System (INIS)

    Bouriaud, O.; Soudani, K.; Breda, N.

    2003-01-01

    Litter fall collection is a direct method widely used to estimate leaf area index (LAI) in broad-leaved forest stands. Indirect measurements using radiation transmittance and gap fraction theory are often compared and calibrated against litter fall, which is considered as a reference method, but few studies address the question of litter specific leaf area (SLA) measurement and variability. SLA (leaf area per unit of dry weight, m 2 ·g -1 ) is used to convert dry leaf litter biomass (g .m - 2) into leaf area per ground unit area (m 2 ·m -2 ). We paid special attention to this parameter in two young beech stands (dense and thinned) in northeastern France. The variability of both canopy (closure, LAI) and site conditions (soil properties, vegetation) was investigated as potential contributing factors to beech SLA variability. A systematic description of soil and floristic composition was performed and three types of soil were identified. Ellenberg's indicator values were averaged for each plot to assess nitrogen soil content. SLA of beech litter was measured three times during the fall in 23 plots in the stands (40 ha). Litter was collected bimonthly in square-shaped traps (0.5 m 2 ) and dried. Before drying, 30 leaves per plot and for each date were sampled, and leaf length, width, and area were measured with the help of a LI-COR areameter. SLA was calculated as the ratio of cumulated leaf area to total dry weight of the 30 leaves. Leaves characteristics per plot were averaged for the three dates of litter collection. Plant area index (PAI), estimated using the LAI-2000 plant canopy analyser and considering only the upper three rings, ranged from 2.9 to 8.1. Specific leaf area of beech litter was also highly different from one plot to the other, ranging from 150 to 320 cm 2 ·g -1 . Nevertheless, no relationship was found between SLA and stand canopy closure or PAI On the contrary, a significant relationship between SLA and soil properties was observed. Both SLA

  9. A Global Data Set of Leaf Photosynthetic Rates, Leaf N and P, and Specific Leaf Area

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This global data set of photosynthetic rates and leaf nutrient traits was compiled from a comprehensive literature review. It includes estimates of Vcmax...

  10. A Global Data Set of Leaf Photosynthetic Rates, Leaf N and P, and Specific Leaf Area

    Data.gov (United States)

    National Aeronautics and Space Administration — This global data set of photosynthetic rates and leaf nutrient traits was compiled from a comprehensive literature review. It includes estimates of Vcmax (maximum...

  11. Estimation of papaya leaf area using the central vein length

    Directory of Open Access Journals (Sweden)

    Campostrini Eliemar

    2001-01-01

    Full Text Available Four genotypes of papaya (Carica papaya L. two from the 'Solo' group (Sunrise Solo and Improved Sunrise Solo line 72/12 and two from the 'Formosa' group (Tainung 02 and Known-You 01, grown in Macaé, RJ, Brazil (lat. 22(0 24' S, long. 41(0 42' W, were used in this study. Twenty-five mature leaves from each genotype were sampled four and five months after seedling transplant to the field to determine the length of the leaf central vein (LLCV and the leaf area (LA. According to covariance analyses there were no significant differences in the slope and intercept of the mathematical models calculated for each genotype. Thus, a single mathematical model (Log LA = 0.315 + 1.85 Log LLCV, R²=0.898 was adjusted to estimate the LA using the length of LLCV for the four genotypes. An unique model can be applied to estimate the LA for the four papaya genotypes using LLCV in the range from 0.25 to 0.60 m, and for papaya trees 150 to 180 days after transplanting.

  12. Determination of alfalfa leaf area by non-destructive method

    Directory of Open Access Journals (Sweden)

    Leonardo Bianco de Carvalho

    2011-11-01

    Full Text Available The knowledge of plant leaf area is important to evaluate the vegetal growth. The objective of this research was to determine a mathematical equation to estimate successfully alfalfa (Medicago sativa leaf area by measuring linear dimensions of the leaf blade of the plant leaflets. The leaves were collected from cultivar ‘Crioula’ cropped at field conditions in Jaboticabal, SP,Brazil. The leaflets length, width and leaf blade area were determined electronically. Linear, geometric and exponential equations were tested, considering the length and width separately and the length × width relation. The lateral leaflets showed similar dimensions and they were different to the central leaflet. So, it was opted to analyze the lateral leaflets together. All equations described satisfactorily the alfalfa leaf area, but it was opted for the linear equation passing through the origin due to its better practical application, showing high significance and normal distribution of residuals. This equation was validated with coefficient of correlation of 0.96, showing high significance (P < 0.01. The alfalfa leaf area can be estimated by the equation LA = 0,691156 × LWct + 0,3652754 × LWlt, where LWct is the central leaflet length × width and LWlt is the sum of the left and right lateral leaflets length × width.

  13. Ramularia leaf spot severity and effects on cotton leaf area and yield

    Directory of Open Access Journals (Sweden)

    João Paulo Ascari

    2016-12-01

    Full Text Available Cotton monoculture favors the development of diseases such as ramularia leaf spot, which causes early defoliation and boll rotting, thus decreasing yield. This study aimed at evaluating the severity of ramularia leaf spot and its effects on cotton leaf area and yield. The experiment was conducted in a triple (4 x 3 x 2 factorial design, consisting of four cultivars (FM940GLT, FM944GL, TMG42WS and TMG43WS, three thirds of the plant (lower, middle and upper and two management conditions (with and without fungicide application. To the variable area under the disease progress curve, the lowest values were observed in the upper third of the TMG42WS and TMG43WS cultivars, with the lower and middle thirds presenting the highest severity. The condition managed with fungicide and the upper third showed the lowest values for area under the disease progress curve. The leaf area was negatively affected by the ramularia leaf spot. Concerning the seed and fiber yields, the highest averages were observed for the middle third and the condition managed with fungicide. There was no statistical difference for cotton yield loss.

  14. Leaf area estimation of cassava from linear dimensions

    Directory of Open Access Journals (Sweden)

    SAMARA ZANETTI

    2017-08-01

    Full Text Available ABSTRACT The objective of this study was to determine predictor models of leaf area of cassava from linear leaf measurements. The experiment was carried out in greenhouse in the municipality of Botucatu, São Paulo state, Brazil. The stem cuttings with 5-7 nodes of the cultivar IAC 576-70 were planted in boxes filled with about 320 liters of soil, keeping soil moisture at field capacity, monitored by puncturing tensiometers. At 80 days after planting, 140 leaves were randomly collected from the top, middle third and base of cassava plants. We evaluated the length and width of the central lobe of leaves, number of lobes and leaf area. The measurements of leaf areas were correlated with the length and width of the central lobe and the number of lobes of the leaves, and adjusted to polynomial and multiple regression models. The linear function that used the length of the central lobe LA = -69.91114 + 15.06462L and linear multiple functions LA = -69.9188 + 15.5102L + 0.0197726K - 0.0768998J or LA = -69.9346 + 15.0106L + 0.188931K - 0.0264323H are suitable models to estimate leaf area of cassava cultivar IAC 576-70.

  15. METHODS OF BIOMONITORING IN URBAN ENVIRONMENT: LEAF AREA AND FRACTAL DIMENSION

    Directory of Open Access Journals (Sweden)

    Nicoleta IANOVICI

    2015-12-01

    Full Text Available In urban conditions, we investigated several leaf traits (leaf area, specific leaf area, fractal dimension and specific leaf weight on Taraxacum officinale, Tilia tomentosa, Aesculus hippocastanum and Ambrosia artemisiifolia. The analyzed organs were mature leaves, on the first indications of senescence. This study used an exact, inexpensive and efficient in terms of costs alternative methods for determining the leaf parameters. On the other hand, this paper presents an application of the leaf area and fractal dimension in the analysis of leaf shape. Our results show that leaf area and fractal dimension are sensitive parameters that can be effectively used in biomonitoring.

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

    International Nuclear Information System (INIS)

    Bailey, Brian N; Mahaffee, Walter F

    2017-01-01

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

  17. 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.

  18. The Design and Implementation of the Leaf Area Index Sensor

    Directory of Open Access Journals (Sweden)

    Xiuhong Li

    2015-03-01

    Full Text Available The quick and accurate acquisition of crop growth parameters on a large scale is important for agricultural management and food security. The combination of photographic and wireless sensor network (WSN techniques can be used to collect agricultural information, such as leaf area index (LAI, over long distances and in real time. Such acquisition not only provides farmers with photographs of crops and suggestions for farmland management, but also the collected quantitative parameters, such as LAI, can be used to support large scale research in ecology, hydrology, remote sensing, etc. The present research developed a Leaf Area Index Sensor (LAIS to continuously monitor the growth of crops in several sampling points, and applied 3G/WIFI communication technology to remotely collect (and remotely setup and upgrade crop photos in real-time. Then the crop photos are automatically processed and LAI is estimated based on the improved leaf area index of Lang and Xiang (LAILX algorithm in LAIS. The research also constructed a database of images and other information relating to crop management. The leaf length and width method (LAILLW can accurately measure LAI through direct field harvest. The LAIS has been tested in several exemplary applications, and validation with LAI from LAILLW. The LAI acquired by LAIS had been proved reliable.

  19. Preliminary validation of leaf area index sensor in Huailai

    Science.gov (United States)

    Cai, Erli; Li, Xiuhong; Liu, Qiang; Dou, Baocheng; Chang, Chongyan; Niu, Hailin; Lin, Xingwen; Zhang, Jialin

    2015-12-01

    Leaf area index (LAI) is a key variable in many land surface models that involve energy and mass exchange between vegetation and the environment. In recent years, extracting vegetation structure parameters from digital photography becomes a widely used indirect method to estimate LAI for its simplicity and ease of use. A Leaf Area Index Sensor (LAIS) system was developed to continuously monitor the growth of crops in several sampling points in Huailai, China. The system applies 3G/WIFI communication technology to remotely collect crop photos in real-time. Then the crop photos are automatically processed and LAI is estimated based on the improved leaf area index of Lang and Xiang (LAILX) algorithm in LAIS. The objective of this study is to primarily verify the LAI estimated from LAIS (Lphoto) through comparing them with the destructive green LAI (Ldest). Ldest was measured across the growing season ntil maximum canopy development while plants are still green. The preliminary verification shows that Lphoto corresponds well with the Ldest (R2=0.975). In general, LAI could be accurately estimated with LAIS and its LAI shows high consistency compared with the destructive green LAI. The continuous LAI measurement obtained from LAIS could be used for the validation of remote sensing LAI products.

  20. Use of remotely sensed precipitation and leaf area index in a distributed hydrological model

    DEFF Research Database (Denmark)

    Andersen, Jens; Dybkjær, Gorm Ibsen; Jensen, Karsten Høgh

    2002-01-01

    distributed hydrological modelling, remote sensing, precipitation, leaf area index, NOAA AVHRR, cold cloud duration......distributed hydrological modelling, remote sensing, precipitation, leaf area index, NOAA AVHRR, cold cloud duration...

  1. Optimal allocation of leaf epidermal area for gas exchange.

    Science.gov (United States)

    de Boer, Hugo J; Price, Charles A; Wagner-Cremer, Friederike; Dekker, Stefan C; Franks, Peter J; Veneklaas, Erik J

    2016-06-01

    A long-standing research focus in phytology has been to understand how plants allocate leaf epidermal space to stomata in order to achieve an economic balance between the plant's carbon needs and water use. Here, we present a quantitative theoretical framework to predict allometric relationships between morphological stomatal traits in relation to leaf gas exchange and the required allocation of epidermal area to stomata. Our theoretical framework was derived from first principles of diffusion and geometry based on the hypothesis that selection for higher anatomical maximum stomatal conductance (gsmax ) involves a trade-off to minimize the fraction of the epidermis that is allocated to stomata. Predicted allometric relationships between stomatal traits were tested with a comprehensive compilation of published and unpublished data on 1057 species from all major clades. In support of our theoretical framework, stomatal traits of this phylogenetically diverse sample reflect spatially optimal allometry that minimizes investment in the allocation of epidermal area when plants evolve towards higher gsmax . Our results specifically highlight that the stomatal morphology of angiosperms evolved along spatially optimal allometric relationships. We propose that the resulting wide range of viable stomatal trait combinations equips angiosperms with developmental and evolutionary flexibility in leaf gas exchange unrivalled by gymnosperms and pteridophytes. © 2016 The Authors New Phytologist © 2016 New Phytologist Trust.

  2. DETERMINATION OF LEAF AREA AND PLANT COVER BY USING DIGITAL IMAGE PROCESSING

    OpenAIRE

    LŐKE, ZS.; SOÓS, G.

    2002-01-01

    The development of different crop models, and crop simulation models in particular, pointed out the importance of quantifying the exact value of the leaf area. To measure the leaf size of plants of pinnatifid form, automatic, portable leaf area meters are necessary. In most places these instruments are not available to measure the assimilatory surface size of crops with special leaf shapes. Any cheap and effective method, that could replace the application of expensive portable area meters co...

  3. Effects of canopy structural variables on retrieval of leaf dry matter content and specific leaf area from remotely sensed data

    NARCIS (Netherlands)

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

    2016-01-01

    Leaf dry matter content (LDMC) and specific leaf area (SLA) are two important traits in measuring biodiversity. To use remote sensing for the estimation of these traits, it is essential to understand the underlying factors that influence their relationships with canopy reflectance. The effect of

  4. Worldwide Historical Estimates of Leaf Area Index, 1932-2000

    Energy Technology Data Exchange (ETDEWEB)

    Scurlock, JMO

    2002-02-06

    Approximately 1000 published estimates of leaf area index (LAI) from nearly 400 unique field sites, covering the period 1932-2000, have been compiled into a single data set. LA1 is a key parameter for global and regional models of biosphere/atmosphere exchange of carbon dioxide, water vapor, and other materials. It also plays an integral role in determining the energy balance of the land surface. This data set provides a benchmark of typical values and ranges of LA1 for a variety of biomes and land cover types, in support of model development and validation of satellite-derived remote sensing estimates of LA1 and other vegetation parameters. The LA1 data are linked to a bibliography of over 300 original source references. These historic LA1 data are mostly from natural and seminatural (managed) ecosystems, although some agricultural estimates are also included. Although methodologies for determining LA1 have changed over the decades, it is useful to represent the inconsistencies (e.g., in maximum value reported for a particular biome) that are actually found in the scientific literature. Needleleaf (coniferous) forests are by far the most commonly measured biome/land cover types in this compilation, with 22% of the measurements from temperate evergreen needleleaf forests, and boreal evergreen needleleaf forests and crops the next most common (about 9% each). About 40% of the records in the data set were published in the past 10 years (1991-2000), with a further 20% collected between 1981 and 1990. Mean LAI ({+-} standard deviation), distributed between 15 biome/land cover classes, ranged from 1.31 {+-} 0.85 for deserts to 8.72 {+-} 4.32 for tree plantations, with evergreen forests (needleleaf and broadleaf) displaying the highest LA1 among the natural terrestrial vegetation classes. We have identified statistical outliers in this data set, both globally and according to the different biome/land cover classes, but despite some decreases in mean LA1 values reported

  5. Bayesian estimation of seasonal course of canopy leaf area index from hyperspectral satellite data

    Science.gov (United States)

    Varvia, Petri; Rautiainen, Miina; Seppänen, Aku

    2018-03-01

    In this paper, Bayesian inversion of a physically-based forest reflectance model is investigated to estimate of boreal forest canopy leaf area index (LAI) from EO-1 Hyperion hyperspectral data. The data consist of multiple forest stands with different species compositions and structures, imaged in three phases of the growing season. The Bayesian estimates of canopy LAI are compared to reference estimates based on a spectral vegetation index. The forest reflectance model contains also other unknown variables in addition to LAI, for example leaf single scattering albedo and understory reflectance. In the Bayesian approach, these variables are estimated simultaneously with LAI. The feasibility and seasonal variation of these estimates is also examined. Credible intervals for the estimates are also calculated and evaluated. The results show that the Bayesian inversion approach is significantly better than using a comparable spectral vegetation index regression.

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

    Directory of Open Access Journals (Sweden)

    Sousa Elias Fernandes de

    2005-01-01

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

  7. Measurement and comparison of remotely derived leaf area index predictors

    Science.gov (United States)

    Jensen, Ryan Russell

    Environmental change occurs in response to both natural and anthropogenic causes. As the world's human population continues to increase, anthropogenic change will also increase. These changes affect the health and vigor of forests throughout the world, including those in north central Florida. Leaf Area Index (LAI), the amount of leaf area per unit ground area, is an important biophysical variable that is directly related to rates of atmospheric gas exchange, biomass partitioning, and productivity. While global and local models that map biophysical parameters are prevalent in the literature, landscape to regional scale models are less common. Therefore, the ability to map and monitor LAI over landscape to regional scale areas is essential for understanding medium scale biophysical properties and how these properties affect biogeochemical cycling, biomass accumulation, and primary productivity. This study develops and verifies several new models to estimate LAI using in situ field measurements throughout north central Florida, Landsat Thematic Mapper remotely sensed imagery, remotely derived vegetation indices, simple and multiple regression, and artificial neural networks (ANNs). This study concludes that while multiple band regression and regression with individual vegetation indices (Normalized Difference Vegetation Index, Soil Adjusted Vegetation Index, Simple Ratio, and Greenness Vegetation Index) can estimate LAI, the most accurate way to estimate regional scale LAI is to train an ANN using in situ LAI data and remote sensing brightness values measured from six different portions of the electromagnetic spectrum. The new ANN method of estimating LAI is then applied to two forest ecology studies. The first study analyzes LAI in longleaf pine/turkey oak sandhills as a function of time since last burn. It concludes that in the absence of fire, sandhill LAI increases, and this may be useful for identifying where prescribed burns need to be done. The second study

  8. Mapping of QTLs for leaf area and the association with winter ...

    African Journals Online (AJOL)

    Variations in plant architecture are often associated with the ability of plants to survive cold stress during winter. In studies of winter hardiness in lentil, it appeared that small leaf area was associated with improved winter survival. Based on this observation, the inheritance of leaf area and the relationship with winter ...

  9. Water use of tree lines: importance of leaf area and micrometeorology in sub-humid Kenya

    NARCIS (Netherlands)

    Radersma, S.; Ong, C.K.; Coe, R.

    2006-01-01

    In this research the relative importance of leaf area and microclimatic factors in determining water use of tree lines was examined in sub-humid Western Kenya. Measurements of tree water-use by a heat-balance technique, leaf area, bulk air saturation deficit, daily radiation, and soil water content

  10. Mapping of QTLs for leaf area and the association with winter ...

    African Journals Online (AJOL)

    Jane

    2010-12-13

    Dec 13, 2010 ... Variations in plant architecture are often associated with the ability of plants to survive cold stress during winter. In studies of winter hardiness in lentil, it appeared that small leaf area was associated with improved winter survival. Based on this observation, the inheritance of leaf area and the relationship ...

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

    Science.gov (United States)

    Jason Cook; Michael R. Saunders

    2013-01-01

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

  12. BIOMONITORING OF URBAN AREA BY ANATOMICAL LEAF CHANGES

    Directory of Open Access Journals (Sweden)

    Elena IRIZA

    2012-01-01

    Full Text Available Plants play a vital role as indicators of pollution. The automobile emissions are high particularly at the traffic intersections. Plants growing under the stress of air pollution show differences in leaf surface characteristics. Light microscopic studies of leaf surface revealed an increase in the number of stomata and trichomes of polluted populations in comparison to control populations of Plantago major and Plantago lanceolata. These changes can be considered as indicators of environmental stress.

  13. Simple models for predicting leaf area of mango (Mangifera indica L.

    Directory of Open Access Journals (Sweden)

    Maryam Ghoreishi

    2012-01-01

    Full Text Available Mango (Mangifera indica L., one of the most popular tropical fruits, is cultivated in a considerable part of southern Iran. Leaf area is a valuable parameter in mango research, especially plant physiological and nutrition field. Most of available methods for estimating plant leaf area are difficult to apply, expensive and destructive which could in turn destroy the canopy and consequently make it difficult to perform further tests on the same plant. Therefore, a non-destructive method which is simple, inexpensive, and could yield an accurate estimation of leaf area will be a great benefit to researchers. A regression analysis was performed in order to determine the relationship between the leaf area and leaf width, leaf length, dry and fresh weight. For this purpose 50 mango seedlings of local selections were randomly took from a nursery in the Hormozgan province, and different parts of plants were separated in laboratory. Leaf area was measured by different method included leaf area meter, planimeter, ruler (length and width and the fresh and dry weight of leaves were also measured. The best regression models were statistically selected using Determination Coefficient, Maximum Error, Model Efficiency, Root Mean Square Error and Coefficient of Residual Mass. Overall, based on regression equation, a satisfactory estimation of leaf area was obtained by measuring the non-destructive parameters, i.e. number of leaf per seedling, length of the longest and width of widest leaf (R2 = 0.88 and also destructive parameters, i.e. dry weight (R2 = 0.94 and fresh weight (R2= 0.94 of leaves.

  14. Taxonomy and remote sensing of leaf mass per area (LMA) in humid tropical forests

    Science.gov (United States)

    Gregory P. Asner; Roberta E. Martin; Raul Tupayachi; Ruth Emerson; Paola Martinez; Felipe Sinca; George V.N. Powell; S. Joseph Wright; Ariel E. Lugo

    2011-01-01

    Leaf mass per area (LMA) is a trait of central importance to plant physiology and ecosystem function, but LMA patterns in the upper canopies of humid tropical forests have proved elusive due to tall species and high diversity. We collected top-of-canopy leaf samples from 2873 individuals in 57 sites spread across the Neotropics, Australasia, and Caribbean and Pacific...

  15. The Microclimate and Leaf Area Index of Yam Plant in the Guinea ...

    African Journals Online (AJOL)

    The amount of light leaf intercepts and hence plant production is mainly the function of its leaf area index (LAI). Experimental research farm was set up at the National Centre for Agriculture Mechanization (NCAM) kilometer 12 Ilorin – Idofian road for two yam growing seasons of 2007/2008 and 2008/2009 to examine the ...

  16. Estimativa da área foliar em milharal Estimating leaf area in corn crops

    Directory of Open Access Journals (Sweden)

    Antonio Roberto Pereira

    1987-01-01

    Full Text Available Num experimento com milho híbrido simples, conduzido no Centro Experimental de Campinas, em 1971/72, testou-se o uso de um fator área foliar, obtido numa repetição, na estimativa da área foliar por planta nas demais repetições. Utilizaram-se os híbridos simples HS1227 (tipo duro e HS7777 (tipo dentado cultivados em duas densidades de plantio: 42.000 e 84.000 plantas por hectare. Não houve diferença estatística entre os valores observados e estimados. O erro-padrão da estimativa, em todos os casos, foi menor que 10%.In a single cross corn hybrid experiment it was tested the use of a Leaf Area Factor, obtained in one replication, in estimating the leaf area per plant of the other replications. It was used the corn hybrids HS1227 (flint and HS7777 (dent grown at the densities of 42,000 and 84,000 plants per hectare. There was no statistical difference between the observed and the estimated values. The standard error of the estimation, in all cases, was lower than 10%.

  17. Comparison of direct and indirect methods for assessing leaf area index across a tropical rain forest landscape

    Science.gov (United States)

    Paulo C. Olivas; Steven F. Oberbauer; David B. Clark; Deborah A. Clark; Michael G. Ryan; Joseph J. O' Brien; Harlyn Ordonez

    2013-01-01

    Many functional properties of forests depend on the leaf area; however, measuring leaf area is not trivial in tall evergreen vegetation. As a result, leaf area is generally estimated indirectly by light absorption methods. These indirect methods are widely used, but have never been calibrated against direct measurements in tropical rain forests, either at point or...

  18. Leaf Area Prediction Using Three Alternative Sampling Methods for Seven Sierra Nevada Conifer Species

    Directory of Open Access Journals (Sweden)

    Dryw A. Jones

    2015-07-01

    Full Text Available Prediction of projected tree leaf area using allometric relationships with sapwood cross-sectional area is common in tree- and stand-level production studies. Measuring sapwood is difficult and often requires destructive sampling. This study tested multiple leaf area prediction models across seven diverse conifer species in the Sierra Nevada of California. The best-fit whole tree leaf area prediction model for overall simplicity, accuracy, and utility for all seven species was a nonlinear model with basal area as the primary covariate. A new non-destructive procedure was introduced to extend the branch summation approach to leaf area data collection on trees that cannot be destructively sampled. There were no significant differences between fixed effects assigned to sampling procedures, indicating that data from the tested sampling procedures can be combined for whole tree leaf area modeling purposes. These results indicate that, for the species sampled, accurate leaf area estimates can be obtained through partially-destructive sampling and using common forest inventory data.

  19. Estimating leaf functional traits by inversion of PROSPECT: Assessing leaf dry matter content and specific leaf area in mixed mountainous forest

    Science.gov (United States)

    Ali, Abebe Mohammed; Darvishzadeh, Roshanak; Skidmore, Andrew K.; Duren, Iris van; Heiden, Uta; Heurich, Marco

    2016-03-01

    Assessments of ecosystem functioning rely heavily on quantification of vegetation properties. The search is on for methods that produce reliable and accurate baseline information on plant functional traits. In this study, the inversion of the PROSPECT radiative transfer model was used to estimate two functional leaf traits: leaf dry matter content (LDMC) and specific leaf area (SLA). Inversion of PROSPECT usually aims at quantifying its direct input parameters. This is the first time the technique has been used to indirectly model LDMC and SLA. Biophysical parameters of 137 leaf samples were measured in July 2013 in the Bavarian Forest National Park, Germany. Spectra of the leaf samples were measured using an ASD FieldSpec3 equipped with an integrating sphere. PROSPECT was inverted using a look-up table (LUT) approach. The LUTs were generated with and without using prior information. The effect of incorporating prior information on the retrieval accuracy was studied before and after stratifying the samples into broadleaf and conifer categories. The estimated values were evaluated using R2 and normalized root mean square error (nRMSE). Among the retrieved variables the lowest nRMSE (0.0899) was observed for LDMC. For both traits higher R2 values (0.83 for LDMC and 0.89 for SLA) were discovered in the pooled samples. The use of prior information improved accuracy of the retrieved traits. The strong correlation between the estimated traits and the NIR/SWIR region of the electromagnetic spectrum suggests that these leaf traits could be assessed at canopy level by using remotely sensed data.

  20. AfSIS MODIS Collection: Leaf Area Index - FPAR, 2012 Release

    Data.gov (United States)

    Center for International Earth Science Information Network, Columbia University — The Africa Soil Information Service (AfSIS) Moderate Resolution Imaging Spectroradiometer (MODIS) Collection Leaf Area Index (LAI) and Photosynthetically Active...

  1. ISLSCP II Leaf Area Index (LAI) from Field Measurements, 1932-2000

    Data.gov (United States)

    National Aeronautics and Space Administration — Leaf Area Index (LAI) data from the scientific literature, covering the period from 1932-2000, have been compiled at the Oak Ridge National Laboratory (ORNL)...

  2. ISLSCP II Leaf Area Index (LAI) from Field Measurements, 1932-2000

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: Leaf Area Index (LAI) data from the scientific literature, covering the period from 1932-2000, have been compiled at the Oak Ridge National Laboratory...

  3. LEAF AREA INDEX (LAI) CHANGE DETECTION ON LOBLOLLY PINE FOREST STANDS WITH COMPLETE UNDERSTORY REMOVAL

    Science.gov (United States)

    The confounding effect of understory vegetation contributions to satellite derived estimates of leaf area index (LAI) was investigated on two loblolly pine (Pinus taeda) forest stands located in the southeastern United States. Previous studies have shown that understory can a...

  4. SAFARI 2000 Leaf Area Measurements at the Mongu Tower Site, Zambia, 2000-2002

    Data.gov (United States)

    National Aeronautics and Space Administration — Data from the LAI-2000 instrument were processed to determine the leaf area index (LAI) at the EOS Validation Core Site in Kataba Local Forest, approximately 20 km...

  5. LBA-ECO CD-04 Leaf Area Index, km 83 Tower Site, Tapajos National Forest, Brazil

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: Leaf area index was estimated in an 18 ha plot at the logged forest tower site, km 83, Tapajos National Forest, Para, Brazil. The plot was adjacent to the...

  6. LBA-ECO CD-04 Leaf Area Index, km 83 Tower Site, Tapajos National Forest, Brazil

    Data.gov (United States)

    National Aeronautics and Space Administration — Leaf area index was estimated in an 18 ha plot at the logged forest tower site, km 83, Tapajos National Forest, Para, Brazil. The plot was adjacent to the eddy flux...

  7. SAFARI 2000 Leaf Area Measurements at the Mongu Tower Site, Zambia, 2000-2002

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: Data from the LAI-2000 instrument were processed to determine the leaf area index (LAI) at the EOS Validation Core Site in Kataba Local Forest,...

  8. BigFoot Leaf Area Index Surfaces for North and South American Sites, 2000-2003

    Data.gov (United States)

    National Aeronautics and Space Administration — The BigFoot project gathered leaf area index (LAI) data for nine EOS Land Validation Sites located from Alaska to Brazil from 2000 to 2003. Each site is...

  9. BigFoot Leaf Area Index Surfaces for North and South American Sites, 2000-2003

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The BigFoot project gathered leaf area index (LAI) data for nine EOS Land Validation Sites located from Alaska to Brazil from 2000 to 2003. Each site is...

  10. Optimising view angles for the estimation of leaf area index via ...

    Indian Academy of Sciences (India)

    spectral/angular remote sensing data for the leaf area index (LAI) inversion, the method of entropy-difference analysis. The proposed ... The presented technique may be useful in designing and evaluating quantitative remote sensing algorithms and ...

  11. DWDM Transmission with LEAF and RDF Structure in 40 Gb/s Single MZM with RZ-DPSK Modulation

    Science.gov (United States)

    Lin, Hsiu-Sheng; Lai, Po-Chou

    2017-06-01

    We propose the experiment transport of 48 Chs 40 Gb/s dense wavelength division multiplexing (DWDM) system that uses larger effective area fiber (LEAF) in combination with reverse dispersion fiber (RDF), which is a dispersion compensation device, in C band (1,530-1,560 nm) and L band (1,570-1,610 nm) wavelength range to solve the dispersion program. The single Mach-Zehnder modulation (MZM) format with erbium-doped fiber amplifier (EDFA) configuration to generate return-to-zero differential phase-shift keying (RZ-DPSK) modulation signal can compensate dispersion impairment in 48×40 Gb/s DWDM system. The proposed 48×40 Gb/s DWDM system successfully employs single MZM RZ-DPSK modulation format to reduce modulation complex configuration with EDFA to promote the power signal and using LEAF and RDF in 28 spans over 3,360 km ultra-long-haul fiber transmission successfully.

  12. The leaf-area shrinkage effect can bias paleoclimate and ecology research.

    Science.gov (United States)

    Blonder, Benjamin; Buzzard, Vanessa; Simova, Irena; Sloat, Lindsey; Boyle, Brad; Lipson, Rebecca; Aguilar-Beaucage, Brianna; Andrade, Angelina; Barber, Benjamin; Barnes, Chris; Bushey, Dharma; Cartagena, Paulina; Chaney, Max; Contreras, Karina; Cox, Mandarava; Cueto, Maya; Curtis, Cannon; Fisher, Mariah; Furst, Lindsey; Gallegos, Jessica; Hall, Ruby; Hauschild, Amelia; Jerez, Alex; Jones, Nadja; Klucas, Aaron; Kono, Anita; Lamb, Mary; Matthai, Jacob David Ruiz; McIntyre, Colten; McKenna, Joshua; Mosier, Nicholas; Navabi, Maya; Ochoa, Alex; Pace, Liam; Plassmann, Ryland; Richter, Rachel; Russakoff, Ben; Aubyn, Holden St; Stagg, Ryan; Sterner, Marley; Stewart, Emily; Thompson, Ting Ting; Thornton, Jake; Trujillo, Parker J; Volpe, Trevor J; Enquist, Brian J

    2012-11-01

    Leaf area is a key trait that links plant form, function, and environment. Measures of leaf area can be biased because leaf area is often estimated from dried or fossilized specimens that have shrunk by an unknown amount. We tested the common assumption that this shrinkage is negligible. We measured shrinkage by comparing dry and fresh leaf area in 3401 leaves of 380 temperate and tropical species and used phylogenetic and trait-based approaches to determine predictors of this shrinkage. We also tested the effects of rehydration and simulated fossilization on shrinkage in four species. We found that dried leaves shrink in area by an average of 22% and a maximum of 82%. Shrinkage in dried leaves can be predicted by multiple morphological traits with a standard deviation of 7.8%. We also found that mud burial, a proxy for compression fossilization, caused negligible shrinkage, and that rehydration, a potential treatment of dried herbarium specimens, eliminated shrinkage. Our findings indicate that the amount of shrinkage is driven by variation in leaf area, leaf thickness, evergreenness, and woodiness and can be reversed by rehydration. The amount of shrinkage may also be a useful trait related to ecologically and physiological differences in drought tolerance and plant life history.

  13. 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.

  14. Why does leaf nitrogen decline within tree canopies less rapidly than light? An explanation from optimization subject to a lower bound on leaf mass per area.

    Science.gov (United States)

    Dewar, Roderick C; Tarvainen, Lasse; Parker, Kathryn; Wallin, Göran; McMurtrie, Ross E

    2012-05-01

    A long-established theoretical result states that, for a given total canopy nitrogen (N) content, canopy photosynthesis is maximized when the within-canopy gradient in leaf N per unit area (N(a)) is equal to the light gradient. However, it is widely observed that N(a) declines less rapidly than light in real plant canopies. Here we show that this general observation can be explained by optimal leaf acclimation to light subject to a lower-bound constraint on the leaf mass per area (m(a)). Using a simple model of the carbon-nitrogen (C-N) balance of trees with a steady-state canopy, we implement this constraint within the framework of the MAXX optimization hypothesis that maximizes net canopy C export. Virtually all canopy traits predicted by MAXX (leaf N gradient, leaf N concentration, leaf photosynthetic capacity, canopy N content, leaf-area index) are in close agreement with the values observed in a mature stand of Norway spruce trees (Picea abies L. Karst.). An alternative upper-bound constraint on leaf photosynthetic capacity (A(sat)) does not reproduce the canopy traits of this stand. MAXX subject to a lower bound on m(a) is also qualitatively consistent with co-variations in leaf N gradient, m(a) and A(sat) observed across a range of temperate and tropical tree species. Our study highlights the key role of constraints in optimization models of plant function.

  15. Joint leaf chlorophyll content and leaf area index retrieval from Landsat data using a regularized model inversion system (REGFLEC)

    KAUST Repository

    Houborg, Rasmus

    2015-01-19

    Leaf area index (LAI) and leaf chlorophyll content (Chll) represent key biophysical and biochemical controls on water, energy and carbon exchange processes in the terrestrial biosphere. In combination, LAI and Chll provide critical information on vegetation density, vitality and photosynthetic potentials. However, simultaneous retrieval of LAI and Chll from space observations is extremely challenging. Regularization strategies are required to increase the robustness and accuracy of retrieved properties and enable more reliable separation of soil, leaf and canopy parameters. To address these challenges, the REGularized canopy reFLECtance model (REGFLEC) inversion system was refined to incorporate enhanced techniques for exploiting ancillary LAI and temporal information derived from multiple satellite scenes. In this current analysis, REGFLEC is applied to a time-series of Landsat data.A novel aspect of the REGFLEC approach is the fact that no site-specific data are required to calibrate the model, which may be run in a largely automated fashion using information extracted entirely from image-based and other widely available datasets. Validation results, based upon in-situ LAI and Chll observations collected over maize and soybean fields in central Nebraska for the period 2001-2005, demonstrate Chll retrieval with a relative root-mean-square-deviation (RMSD) on the order of 19% (RMSD=8.42μgcm-2). While Chll retrievals were clearly influenced by the version of the leaf optical properties model used (PROSPECT), the application of spatio-temporal regularization constraints was shown to be critical for estimating Chll with sufficient accuracy. REGFLEC also reproduced the dynamics of in-situ measured LAI well (r2 =0.85), but estimates were biased low, particularly over maize (LAI was underestimated by ~36 %). This disparity may be attributed to differences between effective and true LAI caused by significant foliage clumping not being properly accounted for in the canopy

  16. Assimilation of satellite reflectance data into a dynamical leaf model to infer seasonally varying leaf areas for climate and carbon models

    Science.gov (United States)

    Liu, Q.; Gu, L.; Dickinson, R. E.; Tian, Y.; Zhou, L.; Post, W. M.

    2008-10-01

    Leaf area index is an important input for many climate and carbon models. The widely used leaf area products derived from satellite-observed surface reflectances contain substantial erratic fluctuations in time due to inadequate atmospheric corrections and observational and retrieval uncertainties. These fluctuations are inconsistent with the seasonal dynamics of leaf area, known to be gradual. Their use in process-based terrestrial carbon models corrupts model behavior, making diagnosis of model performance difficult. We propose a data assimilation approach that combines the satellite observations of Moderate Resolution Imaging Spectroradiometer (MODIS) albedo with a dynamical leaf model. Its novelty is that the seasonal cycle of the directly retrieved leaf areas is smooth and consistent with both observations and current understandings of processes controlling leaf area dynamics. The approach optimizes the dynamical model parameters such that the difference between the estimated surface reflectances based on the modeled leaf area and those of satellite observations is minimized. We demonstrate the usefulness and advantage of our new approach at multiple deciduous forest sites in the United States.

  17. A better way of representing stem area index in two-big-leaf models: the application and impact on canopy integration of leaf nitrogen content

    Science.gov (United States)

    Chen, M.; Butler, E. E.; Wythers, K. R.; Kattge, J.; Ricciuto, D. M.; Thornton, P. E.; Atkin, O. K.; Flores-Moreno, H.; Reich, P. B.

    2017-12-01

    In order to better estimate the carbon budget of the globe, accurately simulating gross primary productivity (GPP) in earth system models is critical. When upscaling leaf level photosynthesis to the canopy, climate models uses different big-leaf schemes. About half of the state-of-the-art earth system models use a "two-big-leaf" scheme that partitions canopies into direct and diffusively illuminated fractions to reduce high bias of GPP simulated by one-big-leaf models. Some two-big-leaf models, such as ACME (identical in this respect to CLM 4.5) add leaf area index (LAI) and stem area index (SAI) together when calculating canopy radiation transfer. This treatment, however, will result in higher fraction of sunlit leaves. It will also lead to an artificial overestimation of canopy nitrogen content. Here we introduce a new algorithm of simulating SAI in a two-big-leaf model. The new algorithm reduced the sunlit leave fraction of the canopy and conserved the nitrogen content from leaf to canopy level. The lower fraction of sunlit leaves reduced global GPP especially in tropical area. Compared to the default model, for the past 100 years (1909-2009), the averaged global annual GPP is lowered by 4.11 PgC year-1 using this new algorithm.

  18. Digital cover photography for estimating leaf area index (LAI) in apple trees using a variable light extinction coefficient.

    Science.gov (United States)

    Poblete-Echeverría, Carlos; Fuentes, Sigfredo; Ortega-Farias, Samuel; Gonzalez-Talice, Jaime; Yuri, Jose Antonio

    2015-01-28

    Leaf area index (LAI) is one of the key biophysical variables required for crop modeling. Direct LAI measurements are time consuming and difficult to obtain for experimental and commercial fruit orchards. Devices used to estimate LAI have shown considerable errors when compared to ground-truth or destructive measurements, requiring tedious site-specific calibrations. The objective of this study was to test the performance of a modified digital cover photography method to estimate LAI in apple trees using conventional digital photography and instantaneous measurements of incident radiation (Io) and transmitted radiation (I) through the canopy. Leaf area of 40 single apple trees were measured destructively to obtain real leaf area index (LAI(D)), which was compared with LAI estimated by the proposed digital photography method (LAI(M)). Results showed that the LAI(M) was able to estimate LAI(D) with an error of 25% using a constant light extinction coefficient (k = 0.68). However, when k was estimated using an exponential function based on the fraction of foliage cover (f(f)) derived from images, the error was reduced to 18%. Furthermore, when measurements of light intercepted by the canopy (Ic) were used as a proxy value for k, the method presented an error of only 9%. These results have shown that by using a proxy k value, estimated by Ic, helped to increase accuracy of LAI estimates using digital cover images for apple trees with different canopy sizes and under field conditions.

  19. Digital Cover Photography for Estimating Leaf Area Index (LAI in Apple Trees Using a Variable Light Extinction Coefficient

    Directory of Open Access Journals (Sweden)

    Carlos Poblete-Echeverría

    2015-01-01

    Full Text Available Leaf area index (LAI is one of the key biophysical variables required for crop modeling. Direct LAI measurements are time consuming and difficult to obtain for experimental and commercial fruit orchards. Devices used to estimate LAI have shown considerable errors when compared to ground-truth or destructive measurements, requiring tedious site-specific calibrations. The objective of this study was to test the performance of a modified digital cover photography method to estimate LAI in apple trees using conventional digital photography and instantaneous measurements of incident radiation (Io and transmitted radiation (I through the canopy. Leaf area of 40 single apple trees were measured destructively to obtain real leaf area index (LAID, which was compared with LAI estimated by the proposed digital photography method (LAIM. Results showed that the LAIM was able to estimate LAID with an error of 25% using a constant light extinction coefficient (k = 0.68. However, when k was estimated using an exponential function based on the fraction of foliage cover (ff derived from images, the error was reduced to 18%. Furthermore, when measurements of light intercepted by the canopy (Ic were used as a proxy value for k, the method presented an error of only 9%. These results have shown that by using a proxy k value, estimated by Ic, helped to increase accuracy of LAI estimates using digital cover images for apple trees with different canopy sizes and under field conditions.

  20. Generalized biomass and leaf area allometric equations for European tree species incorporating stand structure, tree age and climate

    OpenAIRE

    FORRESTER DAVID; TACHAUER ELOISE; ANNIGHOEFER PETER; BARBEITO IGNACIO; PRETZSCH HANS; RUIZ-PEINADO RICARDO; STARK HENDRIK; VACCHIANO GIORGIO; ZLATANOV TZVETAN; CHAKRABORTY TAMALIKA; SAHA SOMID; SILESHI GUDETA W.

    2017-01-01

    Biomass and leaf area equations are often required to assess or model forest productivity, carbon stocks and other ecosystem services. These factors are influenced by climate, age and stand structural attributes including stand density and tree species diversity or species composition. However, such covariates are rarely included in biomass and leaf area equations. We reviewed the literature and built a database of biomass and leaf area equations for 24 European tree species and 3 introduced ...

  1. Vertical leaf area distribution, light transmittance, and application of the Beer-Lambert Law in four mature hardwood stands in the southern Appalachians

    Science.gov (United States)

    James M. Vose; Neal H. Sullivan; Barton D. Clinton; Paul V. Bolstad

    1995-01-01

    We quantified stand leaf area index and vertical leaf area distribution, and developed canopy extinction coefficients (k), in four mature hardwood stands. Leaf area index, calculated from litter fall and specific leaf area (cm²·g-1), ranged from 4.3 to 5.4 m²·m-2. In three of the four stands, leaf area was distributed in...

  2. ESTIMATING LEAF AREA INDEX FOR AN ARID REGION USING ...

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    Department of Geography and Earth Science, University of Nebraska at Kearney, Kearney, NE 68849, USA. 1CPWD, Nirman Bhawan, New ... conditions for the entire field, not just for point locations. Satellite data are acquired in multiple bands. (i.e., ranges of electromagnetic wavelengths). Multiple images of the same area ...

  3. Variation in chlorophyll content per unit leaf area in spring wheat and implications for selection in segregating material.

    Directory of Open Access Journals (Sweden)

    John Hamblin

    Full Text Available Reduced levels of leaf chlorophyll content per unit leaf area in crops may be of advantage in the search for higher yields. Possible reasons include better light distribution in the crop canopy and less photochemical damage to leaves absorbing more light energy than required for maximum photosynthesis. Reduced chlorophyll may also reduce the heat load at the top of canopy, reducing water requirements to cool leaves. Chloroplasts are nutrient rich and reducing their number may increase available nutrients for growth and development. To determine whether this hypothesis has any validity in spring wheat requires an understanding of genotypic differences in leaf chlorophyll content per unit area in diverse germplasm. This was measured with a SPAD 502 as SPAD units. The study was conducted in series of environments involving up to 28 genotypes, mainly spring wheat. In general, substantial and repeatable genotypic variation was observed. Consistent SPAD readings were recorded for different sampling positions on leaves, between different leaves on single plant, between different plants of the same genotype, and between different genotypes grown in the same or different environments. Plant nutrition affected SPAD units in nutrient poor environments. Wheat genotypes DBW 10 and Transfer were identified as having consistent and contrasting high and low average SPAD readings of 52 and 32 units, respectively, and a methodology to allow selection in segregating populations has been developed.

  4. MODIS/Terra+Aqua Leaf Area Index/FPAR 4-Day L4 Global 1km SIN Grid V005

    Data.gov (United States)

    National Aeronautics and Space Administration — Leaf Area Index (LAI) is a dimensionless variable defined as the total one-sided area of green leaves in a vegetation canopy relative to a unit ground area. LAI...

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

    International Nuclear Information System (INIS)

    Moosavi, S.G.

    2012-01-01

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

  6. Seasonal variability of leaf area index and foliar nitrogen in contrasting dry-mesic tundras

    DEFF Research Database (Denmark)

    Campioli, Matteo; Michelsen, Anders; Lemeur, Raoul

    2009-01-01

    Assimilation and exchange of carbon for arctic ecosystems depend strongly on leaf area index (LAI) and total foliar nitrogen (TFN). For dry-mesic tundras, the seasonality of these characteristics is unexplored. We addressed this knowledge gap by measuring variations of LAI and TFN at five contras...

  7. Leaf area index uncertainty estimates for model-data fusion applications

    Science.gov (United States)

    Andrew D. Richardson; D. Bryan Dail; D.Y. Hollinger

    2011-01-01

    Estimates of data uncertainties are required to integrate different observational data streams as model constraints using model-data fusion. We describe an approach with which random and systematic uncertainties in optical measurements of leaf area index [LAI] can be quantified. We use data from a measurement campaign at the spruce-dominated Howland Forest AmeriFlux...

  8. Stomatal conductance, canopy temperature, and leaf area index estimation using remote sensing and OBIA techniques

    Science.gov (United States)

    S. Panda; D.M. Amatya; G. Hoogenboom

    2014-01-01

    Remotely sensed images including LANDSAT, SPOT, NAIP orthoimagery, and LiDAR and relevant processing tools can be used to predict plant stomatal conductance (gs), leaf area index (LAI), and canopy temperature, vegetation density, albedo, and soil moisture using vegetation indices like normalized difference vegetation index (NDVI) or soil adjusted...

  9. LEAF AREA INDEX (LAI) CHANGE DETECTION ANALYSIS ON LOBLOLLY PINE (PINUS TAEDA) FOLLOWING COMPLETE UNDERSTORY REMOVAL

    Science.gov (United States)

    The confounding effect of understory vegetation contributions to satellite-derived estimates of leaf area index (LAI) was investigated on two loblolly pine (Pinus taeda) forest stands located in Virginia and North Carolina. In order to separate NDVI contributions of the dominantc...

  10. Validation of an efficient visual method for estimating leaf area index ...

    African Journals Online (AJOL)

    Leaf area index (LAI) is a key ecophysiological parameter in forest stands because it characterises the interface between atmospheric processes and plant physiology. Several indirect methods for estimating LAI have been developed. However, these methods have limitations that can affect the estimates. This study aimed ...

  11. Amazon forest carbon dynamics predicted by profiles of canopy leaf area and light environment

    Science.gov (United States)

    S. C. Stark; V. Leitold; J. L. Wu; M. O. Hunter; C. V. de Castilho; F. R. C. Costa; S. M. McMahon; G. G. Parker; M. Takako Shimabukuro; M. A. Lefsky; M. Keller; L. F. Alves; J. Schietti; Y. E. Shimabukuro; D. O. Brandao; T. K. Woodcock; N. Higuchi; P. B de Camargo; R. C. de Oliveira; S. R. Saleska

    2012-01-01

    Tropical forest structural variation across heterogeneous landscapes may control above-ground carbon dynamics. We tested the hypothesis that canopy structure (leaf area and light availability) – remotely estimated from LiDAR – control variation in above-ground coarse wood production (biomass growth). Using a statistical model, these factors predicted biomass growth...

  12. Morphological analysis of plant density effects on early leaf area growth in maize

    NARCIS (Netherlands)

    Bos, H.J.; Vos, J.; Struik, P.C.

    2000-01-01

    The mechanisms of density-related reduced leaf area per plant in non-tillering maize (Zea mays) were investigated. Maize cv. Luna crops with a wide range of plant densities were grown in the field at Wageningen for two years. Half of the plots were shaded (50% transmittance). Detailed measurements

  13. Estimating Leaf Area Index for an arid region using Spectral Data ...

    African Journals Online (AJOL)

    Leaf Area Index (LAI) is one of the important crop parameters that can be used to assess crop conditions or drought severity. Estimating LAI for arid regions presents challenge due to the high spatial variability in precipitation and in crop canopies found in such regions. In this study, spectral reflectance of pearl millet was ...

  14. Causes and consequences of variation in leaf mass per area (LMA): a meta-analysis

    NARCIS (Netherlands)

    Poorter, H.; Niinemets, U.; Poorter, L.; Wright, I.J.; Villar, H.

    2009-01-01

    Here, we analysed a wide range of literature data on the leaf dry mass per unit area (LMA). In nature, LMA varies more than 100-fold among species. Part of this variation (c. 35%) can be ascribed to differences between functional groups, with evergreen species having the highest LMA, but most of the

  15. Estimation of leaf area index in cereal crops using red-green images

    DEFF Research Database (Denmark)

    Kirk, Kristian; Andersen, Hans Jørgen; Thomsen, Anton G

    2009-01-01

    A new method for estimating the leaf area index (LAI) in cereal crops based on red-green images taken from above the crop canopy is introduced. The proposed method labels pixels into vegetation and soil classes using a combination of greenness and intensity derived from the red and green colour...

  16. Coffee crop coefficient for precision irrigation based on leaf area index

    Directory of Open Access Journals (Sweden)

    Antonio Roberto Pereira

    2011-01-01

    Full Text Available Crop coefficient (Kc for coffee plantations was found to be linearly related to the leaf area index (L up to 3, i.e., Kc = b L. The basic assumption is that for irrigated trees the water use per unit leaf area (ET LA is equal to the reference evapotranspiration (ETo expressed also on a unit leaf area basis of the reference surface (ET LA = ETo/Lo. As recommended by FAO-56 the leaf area index (Lo for the hypothetical reference surface (grass is equal to 2.88, then the most likely value is b = Lo-1 = 2.88-1 = 0.347. However, for L > 3 (completely covered ground surface Kc decreased from a peak value (~1.05 tending to an asymptotic low value around 0.7 for L > 6, but the linear model gives unrealistic Kc estimates; tentatively the empirical function Kc = 1.8 L-0.5 is offered here as an initial guess due to the lack of experimental results for the interval 3.5 leaf area per coffee tree (LA, m² tree-1, and based on a very limited set of data, LA was estimated as a function of planting density (PD, trees ha-1, i.e., LA = 88.38 - 8.63 Ln (PD. Alternatively, L (< 3.4 can be computed directly as a function of canopy volume (for V < 1.2 m³.

  17. Comparison of the New LEAF Area INDEX (LAI 3G) with the Kazahstan-Wide LEAF Area INDEX DATA SET (GGRS-LAI) over Central ASIA

    Science.gov (United States)

    Kappas, M.; Propastin, P.; Degener, J.; Renchin, T.

    2014-12-01

    Long-term global data sets of Leaf Area Index (LAI) are important for monitoring global vegetation dynamics. LAI indicating phenological development of vegetation is an important state variable for modeling land surface processes. The comparison of long-term data sets is based on two recently available data sets both derived from AVHRR time series. The LAI 3g data set introduced by Zaichun Zhu et al. (2013) is developed from the new improved third generation Global Inventory Modeling and Mapping Studies (GIMMS) Normalized Difference Vegetation Index (NDVI3g) and best-quality MODIS LAI data. The second long-term data set is based on the 8 km spatial resolution GIMMS-AVHRR data (GGRS-data set by Propastin et al. 2012). The GGRS-LAI product uses a three-dimensional physical radiative transfer model which establishes relationship between LAI, vegetation fractional cover and given patterns of surface reflectance, view-illumination conditions and optical properties of vegetation. The model incorporates a number of site/region specific parameters, including the vegetation architecture variables such as leaf angle distribution, clumping index, and light extinction coefficient. For the application of the model to Kazakhstan, the vegetation architecture variables were computed at the local (pixel) level based on extensive field surveys of the biophysical properties of vegetation in representative grassland areas of Kazakhstan. The comparison of both long-term data sets will be used to interpret their quality for scientific research in other disciplines. References:Propastin, P., Kappas, M. (2012). Retrieval of coarse-resolution leaf area index over the Republic of Kazakhstan using NOAA AVHRR satellite data and ground measurements," Remote Sensing, vol. 4, no. 1, pp. 220-246. Zaichun Zhu, Jian Bi, Yaozhong Pan, Sangram Ganguly, Alessandro Anav, Liang Xu, Arindam Samanta, Shilong Piao, Ramakrishna R. Nemani and Ranga B. Myneni (2013). Global Data Sets of Vegetation Leaf Area

  18. The influence of branch order on optimal leaf vein geometries: Murray's law and area preserving branching.

    Directory of Open Access Journals (Sweden)

    Charles A Price

    Full Text Available Models that predict the form of hierarchical branching networks typically invoke optimization based on biomechanical similitude, the minimization of impedance to fluid flow, or construction costs. Unfortunately, due to the small size and high number of vein segments found in real biological networks, complete descriptions of networks needed to evaluate such models are rare. To help address this we report results from the analysis of the branching geometry of 349 leaf vein networks comprising over 1.5 million individual vein segments. In addition to measuring the diameters of individual veins before and after vein bifurcations, we also assign vein orders using the Horton-Strahler ordering algorithm adopted from the study of river networks. Our results demonstrate that across all leaves, both radius tapering and the ratio of daughter to parent branch areas for leaf veins are in strong agreement with the expectation from Murray's law. However, as veins become larger, area ratios shift systematically toward values expected under area-preserving branching. Our work supports the idea that leaf vein networks differentiate roles of leaf support and hydraulic supply between hierarchical orders.

  19. Leaf area index, biomass carbon and growth rate of radiata pine genetic types and relationships with LiDAR

    Science.gov (United States)

    Peter N. Beets; Stephen Reutebuch; Mark O. Kimberley; Graeme R. Oliver; Stephen H. Pearce; Robert J. McGaughey

    2011-01-01

    Relationships between discrete-return light detection and ranging (LiDAR) data and radiata pine leaf area index (LAI), stem volume, above ground carbon, and carbon sequestration were developed using 10 plots with directly measured biomass and leaf area data, and 36 plots with modelled carbon data. The plots included a range of genetic types established on north- and...

  20. Prediction of the competitive effects of weeds on crop yields based on the relative leaf area of weeds

    DEFF Research Database (Denmark)

    Lotz, L. A. P.; Christensen, Svend; Cloutier, D.

    1996-01-01

    L.) and in 11 experiments in spring wheat (Triticum aestivum L.). Most data sets were heller described by a model based on the relative leaf area of the weed than by a hyperbolic model based on weed density. This leaf area model accounted for (part of) the effect of different emerging times of the S....... alba whereas the density model did not. A parameter that allows the maximum yield loss to be smaller than 100% was mostly not needed to describe the effects of weed competition. The parameter that denotes the competitiveness of the weed species with respect to the crop decreased the later the relative...... leaf area of the mustard was determined. This decrease could be estimated from the differences in relative growth rate of the leaf area of crop and S. alba. However, the accuracy of this estimation was poor. The parameter value of the leaf area model varied considerably between sites and years...

  1. Effect of brushwood transposition on the leaf litter arthropod fauna in a cerrado area

    Directory of Open Access Journals (Sweden)

    Paula Cristina Benetton Vergílio

    2013-10-01

    Full Text Available The results of ecological restoration techniques can be monitored through biological indicators of soil quality such as the leaf litter arthropod fauna. This study aimed to determine the immediate effect of brushwood transposition transferred from an area of native vegetation to a disturbed area, on the leaf litter arthropod fauna in a degraded cerrado area. The arthropod fauna of four areas was compared: a degraded area with signal grass, two experimental brushwood transposition areas, with and without castor oil plants, and an area of native cerrado. In total, 7,660 individuals belonging to 23 taxa were sampled. Acari and Collembola were the most abundant taxa in all studied areas, followed by Coleoptera, Diptera, Hemiptera, Hymenoptera, and Symphyla. The brushwood transposition area without castor oil plants had the lowest abundance and dominance and the highest diversity of all areas, providing evidence of changes in the soil community. Conversely, the results showed that the presence of castor oil plants hampered early succession, negatively affecting ecological restoration in this area.

  2. Georeferenced Scanning System to Estimate the Leaf Wall Area in Tree Crops

    Directory of Open Access Journals (Sweden)

    Ignacio del-Moral-Martínez

    2015-04-01

    Full Text Available This paper presents the use of a terrestrial light detection and ranging (LiDAR system to scan the vegetation of tree crops to estimate the so-called pixelated leaf wall area (PLWA. Scanning rows laterally and considering only the half-canopy vegetation to the line of the trunks, PLWA refers to the vertical projected area without gaps detected by LiDAR. As defined, PLWA may be different depending on the side from which the LiDAR is applied. The system is completed by a real-time kinematic global positioning system (RTK-GPS sensor and an inertial measurement unit (IMU sensor for positioning. At the end, a total leaf wall area (LWA is computed and assigned to the X, Y position of each vertical scan. The final value of the area depends on the distance between two consecutive scans (or horizontal resolution, as well as the number of intercepted points within each scan, since PLWA is only computed when the laser beam detects vegetation. To verify system performance, tests were conducted related to the georeferencing task and synchronization problems between GPS time and central processing unit (CPU time. Despite this, the overall accuracy of the system is generally acceptable. The Leaf Area Index (LAI can then be estimated using PLWA as an explanatory variable in appropriate linear regression models.

  3. Georeferenced scanning system to estimate the leaf wall area in tree crops.

    Science.gov (United States)

    del-Moral-Martínez, Ignacio; Arnó, Jaume; Escolà, Alexandre; Sanz, Ricardo; Masip-Vilalta, Joan; Company-Messa, Joaquim; Rosell-Polo, Joan R

    2015-04-10

    This paper presents the use of a terrestrial light detection and ranging (LiDAR) system to scan the vegetation of tree crops to estimate the so-called pixelated leaf wall area (PLWA). Scanning rows laterally and considering only the half-canopy vegetation to the line of the trunks, PLWA refers to the vertical projected area without gaps detected by LiDAR. As defined, PLWA may be different depending on the side from which the LiDAR is applied. The system is completed by a real-time kinematic global positioning system (RTK-GPS) sensor and an inertial measurement unit (IMU) sensor for positioning. At the end, a total leaf wall area (LWA) is computed and assigned to the X, Y position of each vertical scan. The final value of the area depends on the distance between two consecutive scans (or horizontal resolution), as well as the number of intercepted points within each scan, since PLWA is only computed when the laser beam detects vegetation. To verify system performance, tests were conducted related to the georeferencing task and synchronization problems between GPS time and central processing unit (CPU) time. Despite this, the overall accuracy of the system is generally acceptable. The Leaf Area Index (LAI) can then be estimated using PLWA as an explanatory variable in appropriate linear regression models.

  4. 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

  5. Temporal variation and efficiency of leaf area index in young mountain Norway spruce stand

    Czech Academy of Sciences Publication Activity Database

    Pokorný, Radek; Tomášková, Ivana; Havránková, Kateřina

    2008-01-01

    Roč. 127, č. 5 (2008), s. 359-367 ISSN 1612-4669 R&D Projects: GA MŽP(CZ) SP/2D1/93/07; GA MŠk 2B06068 Institutional research plan: CEZ:AV0Z60870520 Keywords : biomass * leaf area duration * Picea abies * thinning Subject RIV: GK - Forestry Impact factor: 1.556, year: 2008

  6. Tree Diversity Enhances Stand Carbon Storage but Not Leaf Area in a Subtropical Forest.

    Science.gov (United States)

    Castro-Izaguirre, Nadia; Chi, Xiulian; Baruffol, Martin; Tang, Zhiyao; Ma, Keping; Schmid, Bernhard; Niklaus, Pascal A

    2016-01-01

    Research about biodiversity-productivity relationships has focused on herbaceous ecosystems, with results from tree field studies only recently beginning to emerge. Also, the latter are concentrated largely in the temperate zone. Tree species diversity generally is much higher in subtropical and tropical than in temperate or boreal forests, with reasons not fully understood. Niche overlap and thus complementarity in the use of resources that support productivity may be lower in forests than in herbaceous ecosystems, suggesting weaker productivity responses to diversity change in forests. We studied stand basal area, vertical structure, leaf area, and their relationship with tree species richness in a subtropical forest in south-east China. Permanent forest plots of 30 x 30 m were selected to span largely independent gradients in tree species richness and secondary successional age. Plots with higher tree species richness had a higher stand basal area. Also, stand basal area increases over a 4-year census interval were larger at high than at low diversity. These effects translated into increased carbon stocks in aboveground phytomass (estimated using allometric equations). A higher variability in tree height in more diverse plots suggested that these effects were facilitated by denser canopy packing due to architectural complementarity between species. In contrast, leaf area was not or even negatively affected by tree diversity, indicating a decoupling of carbon accumulation from leaf area. Alternatively, the same community leaf area might have assimilated more C per time interval in more than in less diverse plots because of differences in leaf turnover and productivity or because of differences in the display of leaves in vertical and horizontal space. Overall, our study suggests that in species-rich forests niche-based processes support a positive diversity-productivity relationship and that this translates into increased carbon storage in long-lived woody

  7. Leaf area index estimation of Eucalyptus grandis W.Hill. in plantations

    Directory of Open Access Journals (Sweden)

    Dubal Papamija-Muñoz

    2012-12-01

    Full Text Available We estimated leaf area index (LAI in Eucalyptus grandis W.Hill. plantations in four farms in the Smurfit Kappa Carton de Colombia (SKCC with three farms located in the city of Popayan (Cauca and one located in the municipality of Restrepo (Valle del Cauca. Each farm had three fertilized and three unfertilized plots with 64 individuals in each. We used three methods, Plant Canopy Analyzer 2000 (PCA 2000, flat photograph PIPEcv software and a destructive method, which was generated using a mathematical model. The first two methods were measured bimonthly for a year and the final method required trees being cut to measure their diameter. Estimation of leaf area index was 2.01 for PCA 2000, 3.12 for PIPEcv and 2.83 for the mathematical model. These values correspond to the average and range of leaf area indices obtained for each method on all farms. Statistically the three methodologies developed in this study were not closely related.

  8. First direct landscape-scale measurement of tropical rain forest Leaf Area Index, a key driver of global primary productivity

    Science.gov (United States)

    David B. Clark; Paulo C. Olivas; Steven F. Oberbauer; Deborah A. Clark; Michael G. Ryan

    2008-01-01

    Leaf Area Index (leaf area per unit ground area, LAI) is a key driver of forest productivity but has never previously been measured directly at the landscape scale in tropical rain forest (TRF). We used a modular tower and stratified random sampling to harvest all foliage from forest floor to canopy top in 55 vertical transects (4.6 m2) across 500 ha of old growth in...

  9. Functional design space of single-veined leaves: role of tissue hydraulic properties in constraining leaf size and shape.

    Science.gov (United States)

    Zwieniecki, Maciej A; Boyce, C Kevin; Holbrook, N Michele

    2004-10-01

    Morphological diversity of leaves is usually quantified with geometrical characters, while in many cases a simple set of biophysical parameters are involved in constraining size and shape. One of the main physiological functions of the leaf is transpiration and thus one can expect that leaf hydraulic parameters can be used to predict potential morphologies, although with the caveat that morphology in turn influences physiological parameters including light interception and boundary layer thickness and thereby heat transfer and net photosynthesis. An iterative model was used to determine the relative sizes and shapes that are functionally possible for single-veined leaves as defined by their ability to supply the entire leaf lamina with sufficient water to prevent stomatal closure. The model variables include the hydraulic resistances associated with vein axial and radial transport, as well as with water movement through the mesophyll and the leaf surface. The four parameters included in the model are sufficient to define a hydraulic functional design space that includes all single-veined leaf shapes found in nature, including scale-, awl- and needle-like morphologies. This exercise demonstrates that hydraulic parameters have dissimilar effects: surface resistance primarily affects leaf size, while radial and mesophyll resistances primarily affect leaf shape. These distinctions between hydraulic parameters, as well as the differential accessibility of different morphologies, might relate to the convergent evolutionary patterns seen in a variety of fossil lineages concerning overall morphology and anatomical detail that frequently have evolved in linear and simple multi-veined leaves.

  10. Estimation of leaf area index in the sunflower as a function of thermal time1

    Directory of Open Access Journals (Sweden)

    Dioneia Daiane Pitol Lucas

    Full Text Available The aim of this study was to obtain a mathematical model for estimating the leaf area index (LAI of a sunflower crop as a function of accumulated thermal time. Generating the models and testing their coefficients was carried out using data obtained from experiments carried out for different sowing dates in the crop years of 2007/08, 2008/09, 2009/10 and 2010/11 with two sunflower hybrids, Aguará 03 and Hélio 358. Linear leaf dimensions were used for the non-destructive measurement of the leaf area, and thermal time was used to quantify the biological time. With the data for accumulated thermal time (TTa and LAI known for any one day after emergence, mathematical models were generated for estimating the LAI. The following models were obtained, as they presented the best fit (lowest rootmean- square error, RMSE: gaussian peak, cubic polynomial, sigmoidal and an adjusted compound model, the modified sigmoidal. The modified sigmoidal model had the best fit to the generation data and the highest value for the coefficient of determination (R2. In testing the models, the lowest values for root-mean-square error, and the highest R2 between the observed and estimated values were obtained with the modified sigmoidal model.

  11. Measurement of Forest Leaf Area over an Extensive Transect with Airborne Laser Altimetry for Global Change Studies

    Science.gov (United States)

    Kusakabe, T.; Tsuzuki, H.; Abraham, E. R.; Sweda, T.

    2001-12-01

    The climate warming resulting from increasing anthropogenic carbon dioxide and other greenhouse gasses is expected to be most prominent in the subarctic-boreal region of the Northern Hemisphere. With an objective of setting up a baseline to monitor possible vegetation change in terms of change in leaf area index in this region, a continuous vegetation profile extending 600 km from Edmonton, Alberta to Cluff Lake, Saskatchewan, Canada was measured using an airborne infrared laser altimeter mounted on a helicopter. The ground truth survey at some 30 plots located directly under the airborne laser profiling track revealed that leaf area index correlated well with standing stock, which further in turn correlated well with the area of vegetation profile. Thus, using regression of leaf area index and standing stock respectively upon stand stock and vegetation profile, a continuous distribution of leaf area index over the same 600 km laser profiling track was estimated. The distribution of leaf area index not only corresponded well with biome type, but also showed characteristic change in accordance with environmental gradient within a given biome, thus confirming that airborne laser altimetry is a powerful tool for measuring and monitoring such important vegetation characteristics as standing volume, leaf area index, etc. over an extensive area.

  12. MODIS/Terra Leaf Area Index/FPAR 8-Day L4 Global 1km SIN Grid V005

    Data.gov (United States)

    National Aeronautics and Space Administration — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 1-kilometer...

  13. A Global Database of Field-observed Leaf Area Index in Woody Plant Species, 1932-2011

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides global leaf area index (LAI) values for woody species. The data are a compilation of field-observed data from 1,216 locations obtained from...

  14. A Global Database of Field-observed Leaf Area Index in Woody Plant Species, 1932-2011

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set provides global leaf area index (LAI) values for woody species. The data are a compilation of field-observed data from 1,216 locations...

  15. MODIS/Terra+Aqua Leaf Area Index/FPAR 8-Day L4 Global 1km SIN Grid V005

    Data.gov (United States)

    National Aeronautics and Space Administration — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 1-kilometer...

  16. MODIS/Aqua Leaf Area Index/FPAR 8-Day L4 Global 1km SIN Grid V005

    Data.gov (United States)

    National Aeronautics and Space Administration — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 1-kilometer...

  17. NOAA Climate Data Record (CDR) of Leaf Area Index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), Version 4

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains gridded daily Leaf Area Index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) derived from the NOAA Climate Data...

  18. MODIS/Aqua Leaf Area Index/FPAR 8-Day L4 Global 500m SIN Grid V006

    Data.gov (United States)

    National Aeronautics and Space Administration — The MYD15A2H version 6 MODIS Level 4, Combined Fraction of Photosynthetically Active Radiation (FPAR), and Leaf Area Index (LAI) product is an 8-day composite data...

  19. MODIS/Terra+Aqua Leaf Area Index/FPAR 8-Day L4 Global 500m SIN Grid V006

    Data.gov (United States)

    National Aeronautics and Space Administration — The MCD15A2H version 6 MODIS Level 4, Combined Fraction of Photosynthetically Active Radiation (FPAR), and Leaf Area Index (LAI) product is an 8-day composite...

  20. MODIS/Terra+Aqua Leaf Area Index/FPAR 4-Day L4 Global 500m SIN Grid V006

    Data.gov (United States)

    National Aeronautics and Space Administration — The MCD15A3H version 6 MODIS Level 4, Combined Fraction of Photosynthetically Active Radiation (FPAR), and Leaf Area Index (LAI) product is a 4-day composite data...

  1. Determining the K coefficient to leaf area index estimations in a tropical dry forest.

    Science.gov (United States)

    Magalhães, Sarah Freitas; Calvo-Rodriguez, Sofia; do Espírito Santo, Mário Marcos; Sánchez Azofeifa, Gerardo Arturo

    2018-03-15

    Vegetation indices are useful tools to remotely estimate several important parameters related to ecosystem functioning. However, improving and validating estimations for a wide range of vegetation types are necessary. In this study, we provide a methodology for the estimation of the leaf area index (LAI) in a tropical dry forest (TDF) using the light diffusion through the canopy as a function of the successional stage. For this purpose, we estimated the K coefficient, a parameter that relates the normalized difference vegetation index (NDVI) to LAI, based on photosynthetically active radiation (PAR) and solar radiation. The study was conducted in the Mata Seca State Park, in southeastern Brazil, from 2012 to 2013. We defined four successional stages (very early, early, intermediate, and late) and established one optical phenology tower at one plot of 20 × 20 m per stage. Towers measured the incoming and reflected solar radiation and PAR for NDVI calculation. For each plot, we established 24 points for LAI sampling through hemispherical photographs. Because leaf cover is highly seasonal in TDFs, we determined ΔK (leaf growth phase) and K max (leaf maturity phase). We detected a strong correlation between NDVI and LAI, which is necessary for a reliable determination of the K coefficient. Both NDVI and LAI varied significantly between successional stages, indicating sensitivity to structural changes in forest regeneration. Furthermore, the K values differed between successional stages and correlated significantly with other environmental variables such as air temperature and humidity, fraction of absorbed PAR, and soil moisture. Thus, we established a model based on spectral properties of the vegetation coupled with biophysical characteristics in a TDF that makes possible to estimate LAI from NDVI values. The application of the K coefficient can improve remote estimations of forest primary productivity and gases and energy exchanges between vegetation and

  2. Determining the K coefficient to leaf area index estimations in a tropical dry forest

    Science.gov (United States)

    Magalhães, Sarah Freitas; Calvo-Rodriguez, Sofia; do Espírito Santo, Mário Marcos; Sánchez Azofeifa, Gerardo Arturo

    2018-03-01

    Vegetation indices are useful tools to remotely estimate several important parameters related to ecosystem functioning. However, improving and validating estimations for a wide range of vegetation types are necessary. In this study, we provide a methodology for the estimation of the leaf area index (LAI) in a tropical dry forest (TDF) using the light diffusion through the canopy as a function of the successional stage. For this purpose, we estimated the K coefficient, a parameter that relates the normalized difference vegetation index (NDVI) to LAI, based on photosynthetically active radiation (PAR) and solar radiation. The study was conducted in the Mata Seca State Park, in southeastern Brazil, from 2012 to 2013. We defined four successional stages (very early, early, intermediate, and late) and established one optical phenology tower at one plot of 20 × 20 m per stage. Towers measured the incoming and reflected solar radiation and PAR for NDVI calculation. For each plot, we established 24 points for LAI sampling through hemispherical photographs. Because leaf cover is highly seasonal in TDFs, we determined ΔK (leaf growth phase) and K max (leaf maturity phase). We detected a strong correlation between NDVI and LAI, which is necessary for a reliable determination of the K coefficient. Both NDVI and LAI varied significantly between successional stages, indicating sensitivity to structural changes in forest regeneration. Furthermore, the K values differed between successional stages and correlated significantly with other environmental variables such as air temperature and humidity, fraction of absorbed PAR, and soil moisture. Thus, we established a model based on spectral properties of the vegetation coupled with biophysical characteristics in a TDF that makes possible to estimate LAI from NDVI values. The application of the K coefficient can improve remote estimations of forest primary productivity and gases and energy exchanges between vegetation and atmosphere

  3. Assimilating Remote Sensing Observations of Leaf Area Index and Soil Moisture for Wheat Yield Estimates: An Observing System Simulation Experiment

    Science.gov (United States)

    Nearing, Grey S.; Crow, Wade T.; Thorp, Kelly R.; Moran, Mary S.; Reichle, Rolf H.; Gupta, Hoshin V.

    2012-01-01

    Observing system simulation experiments were used to investigate ensemble Bayesian state updating data assimilation of observations of leaf area index (LAI) and soil moisture (theta) for the purpose of improving single-season wheat yield estimates with the Decision Support System for Agrotechnology Transfer (DSSAT) CropSim-Ceres model. Assimilation was conducted in an energy-limited environment and a water-limited environment. Modeling uncertainty was prescribed to weather inputs, soil parameters and initial conditions, and cultivar parameters and through perturbations to model state transition equations. The ensemble Kalman filter and the sequential importance resampling filter were tested for the ability to attenuate effects of these types of uncertainty on yield estimates. LAI and theta observations were synthesized according to characteristics of existing remote sensing data, and effects of observation error were tested. Results indicate that the potential for assimilation to improve end-of-season yield estimates is low. Limitations are due to a lack of root zone soil moisture information, error in LAI observations, and a lack of correlation between leaf and grain growth.

  4. Analysis, improvement and application of the MODIS leaf area index products

    Science.gov (United States)

    Yang, Wenze

    Green leaf area governs the exchanges of energy, mass and momentum between the Earth's surface and the atmosphere. Therefore, leaf area index (LAI) and fraction of incident photosynthetically active radiation (0.4-0.7 mum) absorbed by the vegetation canopy (FPAR) are widely used in vegetation monitoring and modeling. The launch of Terra and Aqua satellites with the moderate resolution imaging spectroradiometer (MODIS) instrument onboard provided the first global products of LAI and FPAR, derived mainly from an algorithm based on radiative transfer. The objective of this research is to comprehensively evaluate the Terra and Aqua MODIS LAI/FPAR products. Large volumes of these products have been analyzed with the goal of understanding product quality with respect to version (Collection 3 versus 4), algorithm (main versus back-up), snow (snow-free versus snow on the ground) and cloud (cloud-free versus cloudy) conditions. Field validation efforts identified several key factors that influence the accuracy of algorithm retrievals. The strategy of validation efforts guiding algorithm refinements has led to progressively more accurate LAI/FPAR products. The combination of products derived from the Terra and Aqua MODIS sensors increases the success rate of the main radiative transfer algorithm by 10-20 percent over woody vegetation. The Terra Collection 4 LAI data reveal seasonal swings in green leaf area of about 25 percent in a majority of the Amazon rainforests caused by variability in cloud cover and light. The timing and the influence of this seasonal cycle are critical to understanding tropical plant adaptation patterns and ecological processes. The results presented in this dissertation suggest how the product quality has gradually improved largely through the efforts of validation activities. The Amazon case study highlights the utility of these data sets for monitoring global vegetation dynamics. Thus, these results can be seen as a benchmark for evaluation of

  5. Leaf Area Index (LAI Estimation of Boreal Forest Using Wide Optics Airborne Winter Photos

    Directory of Open Access Journals (Sweden)

    Pauline Stenberg

    2009-12-01

    Full Text Available A new simple airborne method based on wide optics camera is developed for leaf area index (LAI estimation in coniferous forests. The measurements are carried out in winter, when the forest floor is completely snow covered and thus acts as a light background for the hemispherical analysis of the images. The photos are taken automatically and stored on a laptop during the flights. The R2 value of the linear regression of the airborne and ground based LAI measurements was 0.89.

  6. Leaf area index, leaf mass density, and allometric relationships derived from harvest of blue oaks in a California oak savanna

    Science.gov (United States)

    John F. Karlik; Alistair H. McKay

    2002-01-01

    Given the key role played by biogenic volatile organic compounds (BVOC) in tropospheric chemistry and regional air quality, it is critical to generate accurate BVOC emission inventories. Because oak species found in California often have high BVOC emission rates, and are often of large stature with corresponding large leaf masses, oaks may be the most important genus...

  7. LEAF AREA INDEX MONITORING AND PROTECTIONG THROUGH REMOTE SENSING IN THE ITATIAIA NATIONAL PARK

    Directory of Open Access Journals (Sweden)

    Otávio Augusto Carvalho Nassur

    2015-09-01

    Full Text Available Satellite images of earth observation and meteorological sensors have been used for monitoring land use. Recently products obtained from satellite images have been disseminated, among them, several vegetation indices. EUMETSAT, through the Land –SAF, offers, among other products, the Leaf Area Index (LAI. Daily LAI products have beem acquired in raster format corresponding from 01/01/2010 to 30/12/2010. From a pixel located in the central portion of the Itatiaia National Park, a time series was generated, which was analyzed aiming at assessing the dynamics of leaf area index. The tendency observed in this period indicates that LAI decreased during 2010. It was possible to observe that changes in vegetation have close relationship with changes in rainfall and fires that affect the region. The ARIMA (7 1 0 model was able to describe the behavior of the LAI series, producing white noise and indicating correlations among 1, 6 and 7 days among the past observations. The prediction for future values resulted in an average error of 2.74%, indicating the potential of the model to identify changes in vegetation. Models of ARIMA class, in conjunction with orbital products, stand out as promises for use in the analysis of the vegetation of protected areas.

  8. Indirect Field Measurement of Wine-Grape Vineyard Canopy Leaf Area Index

    Science.gov (United States)

    Johnson, Lee F.; Pierce, Lars L.; Skiles, J. W. (Technical Monitor)

    2002-01-01

    Leaf area index (LAI) indirect measurements were made at 12 study plots in California's Napa Valley commercial wine-grape vineyards with a LI-COR LI-2000 Plant Canopy Analyzer (PCA). The plots encompassed different trellis systems, biological varieties, and planting densities. LAI ranged from 0.5 - 2.25 sq m leaf area/ sq m ground area according to direct (defoliation) measurements. Indirect LAI reported by the PCA was significantly related to direct LAI (r(exp 2) = 0.78, p less than 001). However, the PCA tended to underestimate direct LAI by about a factor of two. Narrowing the instrument's conical field of view from 148 deg to 56 deg served to increase readings by approximately 30%. The PCA offers a convenient way to discern relative differences in vineyard canopy density. Calibration by direct measurement (defoliation) is recommended in cases where absolute LAI is desired. Calibration equations provided herein may be inverted to retrieve actual vineyard LAI from PCA readings.

  9. "Diminishing returns" in the scaling of leaf area vs. dry mass in Wuyi Mountain bamboos, Southeast China.

    Science.gov (United States)

    Sun, Jun; Fan, Ruirui; Niklas, Karl J; Zhong, Quanlin; Yang, Fuchun; Li, Man; Chen, Xiaoping; Sun, Mengke; Cheng, Dongliang

    2017-07-01

    Leaf area and dry mass are crucial for plant metabolic performance. The "diminishing returns" hypothesis predicts that leaf area will scale less than one with respect to leaf dry mass, indicating that the cost of light interception increases with leaf area. However, it remains unclear whether and how this scaling relationship varies among species growing in different environments. More than 2000 measurements from five bamboo species adapted to high and low light and growing at different elevations in Wuyi Mountains, Southeast China, were used to explore how the leaf area vs. dry mass scaling relationship was affected by light and elevation. The data indicate that (1) the normalization constants for leaf area vs. dry mass were positively but not significantly correlated with increasing leaf size and that (2) the scaling exponents remained numerically invariant among all five bamboo species, with a common slope of 0.85. Standardized major axis (SMA) analyses and comparisons of 95% confidence intervals also showed that the numerical values of the scaling exponents did not differ regardless of elevation and were similar between shaded and unshaded adapted species, whereas the numerical values of the normalization constants increased with decreasing light. The data collected for all five bamboo species are consistent with the "diminishing returns" hypothesis, i.e., the scaling exponents governing the leaf area vs. dry mass scaling relationship are less than one within and across species and are insensitive to light conditions or elevation. © 2017 Sun et al. Published by the Botanical Society of America. This work is licensed under a Creative Commons Attribution License (CC-BY).

  10. Validation of Leaf Area Index measurements based on the Wireless Sensor Network platform

    Science.gov (United States)

    Song, Q.; Li, X.; Liu, Q.

    2017-12-01

    The leaf area index (LAI) is one of the important parameters for estimating plant canopy function, which has significance for agricultural analysis such as crop yield estimation and disease evaluation. The quick and accurate access to acquire crop LAI is particularly vital. In the study, LAI measurement of corn crops is mainly through three kinds of methods: the leaf length and width method (LAILLW), the instruments indirect measurement method (LAII) and the leaf area index sensor method(LAIS). Among them, LAI value obtained from LAILLW can be regarded as approximate true value. LAI-2200,the current widespread LAI canopy analyzer,is used in LAII. LAIS based on wireless sensor network can realize the automatic acquisition of crop images,simplifying the data collection work,while the other two methods need person to carry out field measurements.Through the comparison of LAIS and other two methods, the validity and reliability of LAIS observation system is verified. It is found that LAI trend changes are similar in three methods, and the rate of change of LAI has an increase with time in the first two months of corn growth when LAIS costs less manpower, energy and time. LAI derived from LAIS is more accurate than LAII in the early growth stage,due to the small blade especially under the strong light. Besides, LAI processed from a false color image with near infrared information is much closer to the true value than true color picture after the corn growth period up to one and half months.

  11. Estimation of leaf area index and its sunlit portion from DSCOVR EPIC data: Theoretical basis.

    Science.gov (United States)

    Yang, Bin; Knyazikhin, Yuri; Mõttus, Matti; Rautiainen, Miina; Stenberg, Pauline; Yan, Lei; Chen, Chi; Yan, Kai; Choi, Sungho; Park, Taejin; Myneni, Ranga B

    2017-09-01

    This paper presents the theoretical basis of the algorithm designed for the generation of leaf area index and diurnal course of its sunlit portion from NASA's Earth Polychromatic Imaging Camera (EPIC) onboard NOAA's Deep Space Climate Observatory (DSCOVR). The Look-up-Table (LUT) approach implemented in the MODIS operational LAI/FPAR algorithm is adopted. The LUT, which is the heart of the approach, has been significantly modified. First, its parameterization incorporates the canopy hot spot phenomenon and recent advances in the theory of canopy spectral invariants. This allows more accurate decoupling of the structural and radiometric components of the measured Bidirectional Reflectance Factor (BRF), improves scaling properties of the LUT and consequently simplifies adjustments of the algorithm for data spatial resolution and spectral band compositions. Second, the stochastic radiative transfer equations are used to generate the LUT for all biome types. The equations naturally account for radiative effects of the three-dimensional canopy structure on the BRF and allow for an accurate discrimination between sunlit and shaded leaf areas. Third, the LUT entries are measurable, i.e., they can be independently derived from both below canopy measurements of the transmitted and above canopy measurements of reflected radiation fields. This feature makes possible direct validation of the LUT, facilitates identification of its deficiencies and development of refinements. Analyses of field data on canopy structure and leaf optics collected at 18 sites in the Hyytiälä forest in southern boreal zone in Finland and hyperspectral images acquired by the EO-1 Hyperion sensor support the theoretical basis.

  12. Improved estimation of leaf area index and leaf chlorophyll content of a potato crop using multi-angle spectral data - potential of unmanned aerial vehicle imagery

    Science.gov (United States)

    Roosjen, Peter P. J.; Brede, Benjamin; Suomalainen, Juha M.; Bartholomeus, Harm M.; Kooistra, Lammert; Clevers, Jan G. P. W.

    2018-04-01

    In addition to single-angle reflectance data, multi-angular observations can be used as an additional information source for the retrieval of properties of an observed target surface. In this paper, we studied the potential of multi-angular reflectance data for the improvement of leaf area index (LAI) and leaf chlorophyll content (LCC) estimation by numerical inversion of the PROSAIL model. The potential for improvement of LAI and LCC was evaluated for both measured data and simulated data. The measured data was collected on 19 July 2016 by a frame-camera mounted on an unmanned aerial vehicle (UAV) over a potato field, where eight experimental plots of 30 × 30 m were designed with different fertilization levels. Dozens of viewing angles, covering the hemisphere up to around 30° from nadir, were obtained by a large forward and sideways overlap of collected images. Simultaneously to the UAV flight, in situ measurements of LAI and LCC were performed. Inversion of the PROSAIL model was done based on nadir data and based on multi-angular data collected by the UAV. Inversion based on the multi-angular data performed slightly better than inversion based on nadir data, indicated by the decrease in RMSE from 0.70 to 0.65 m2/m2 for the estimation of LAI, and from 17.35 to 17.29 μg/cm2 for the estimation of LCC, when nadir data were used and when multi-angular data were used, respectively. In addition to inversions based on measured data, we simulated several datasets at different multi-angular configurations and compared the accuracy of the inversions of these datasets with the inversion based on data simulated at nadir position. In general, the results based on simulated (synthetic) data indicated that when more viewing angles, more well distributed viewing angles, and viewing angles up to larger zenith angles were available for inversion, the most accurate estimations were obtained. Interestingly, when using spectra simulated at multi-angular sampling configurations as

  13. Detection of chlorophyll and leaf area index dynamics from sub-weekly hyperspectral imagery

    Science.gov (United States)

    Houborg, Rasmus; McCabe, Matthew F.; Angel, Yoseline; Middleton, Elizabeth M.

    2016-10-01

    Temporally rich hyperspectral time-series can provide unique time critical information on within-field variations in vegetation health and distribution needed by farmers to effectively optimize crop production. In this study, a dense timeseries of images were acquired from the Earth Observing-1 (EO-1) Hyperion sensor over an intensive farming area in the center of Saudi Arabia. After correction for atmospheric effects, optimal links between carefully selected explanatory hyperspectral vegetation indices and target vegetation characteristics were established using a machine learning approach. A dataset of in-situ measured leaf chlorophyll (Chll) and leaf area index (LAI), collected during five intensive field campaigns over a variety of crop types, were used to train the rule-based predictive models. The ability of the narrow-band hyperspectral reflectance information to robustly assess and discriminate dynamics in foliar biochemistry and biomass through empirical relationships were investigated. This also involved evaluations of the generalization and reproducibility of the predictions beyond the conditions of the training dataset. The very high temporal resolution of the satellite retrievals constituted a specifically intriguing feature that facilitated detection of total canopy Chl and LAI dynamics down to sub-weekly intervals. The study advocates the benefits associated with the availability of optimum spectral and temporal resolution spaceborne observations for agricultural management purposes.

  14. LEAF AREA INDEX IN WINTER WHEAT: RESPONSE ON SEED RATE AND NITROGEN APPLICATION BY DIFFERENT VARIETIES

    Directory of Open Access Journals (Sweden)

    M BAVEC

    2007-12-01

    Full Text Available The most important photosynthesis acceptor – leaf area vary among cultivation measures and it is limited factor for creating exact growth models in common winter wheat. The objective of this study was to investigate changes of leaf area index (LAI affected by agricultural treatments – 4 sowing rates and 9 nitrogen treatments based on fertilising rates, target values based on soil mineral nitrogen and plant sap tests target values including different varieties. Increasing sowing rates from 350 to 800 viable seeds m-2 increased LAI at EC 75 stage from 2.9 to 5.5, where LAI 4.1 at 500 seeds m-2 did not vary between lower and higher rates; also at EC 85 stage LAIs did not differ significantly. At EC 75 stage LAI differed among control and nitrogen treatments from 1.0 to 6.5 and at EC 85 stage from 0.1 to 2.4, with differences in interaction among varieties. Higher nitrogen rates for first and second top dressing increased LAI in both stages compared without dressing treatments. Due to significant differences among LAI as consequence of production system, we suggest to take this into account in every prediction and modelling of growth in winter wheat.

  15. Detection of chlorophyll and leaf area index dynamics from sub-weekly hyperspectral imagery

    KAUST Repository

    Houborg, Rasmus

    2016-10-25

    Temporally rich hyperspectral time-series can provide unique time critical information on within-field variations in vegetation health and distribution needed by farmers to effectively optimize crop production. In this study, a dense timeseries of images were acquired from the Earth Observing-1 (EO-1) Hyperion sensor over an intensive farming area in the center of Saudi Arabia. After correction for atmospheric effects, optimal links between carefully selected explanatory hyperspectral vegetation indices and target vegetation characteristics were established using a machine learning approach. A dataset of in-situ measured leaf chlorophyll (Chll) and leaf area index (LAI), collected during five intensive field campaigns over a variety of crop types, were used to train the rule-based predictive models. The ability of the narrow-band hyperspectral reflectance information to robustly assess and discriminate dynamics in foliar biochemistry and biomass through empirical relationships were investigated. This also involved evaluations of the generalization and reproducibility of the predictions beyond the conditions of the training dataset. The very high temporal resolution of the satellite retrievals constituted a specifically intriguing feature that facilitated detection of total canopy Chl and LAI dynamics down to sub-weekly intervals. The study advocates the benefits associated with the availability of optimum spectral and temporal resolution spaceborne observations for agricultural management purposes.

  16. Leaf area index estimation of Eucalyptus plantation using three alternative methodologies

    Directory of Open Access Journals (Sweden)

    Roberta Zecchini Cantinho

    2014-09-01

    Full Text Available Leaf Area Index (LAI and Vegetation Area Index (VAI estimations have been performed in 36 sample points located in Eucalyptus sp. canopies situated in Aracruz and São Mateus (ES towns and from FIBRIA S/A company. Three different techniques have been applied: destructive method, hemispherical photos taken inside the canopies and LAI-2000 (LICOR. The field data collections were carried out in two seasons in order to detect phenological changes that should affect both LAI and VAI values. LAI values estimated by destructive method were higher than VAI values estimated by the indirect methods in absolute terms. During the rainy season the relationships between LAI and VAI, for the two indirect methods, were stronger and more consistent than those verified for the dry season. The relationships between VAI (indirect methods were consistent than those calculated between LAI and VAI.

  17. Euro Area: Single Currency - National Money Creation

    OpenAIRE

    Stefan Kooths; Björn van Roye

    2012-01-01

    The Eurosystem has been pursuing a crisis management policy for more than four years now. This policy aims primarily at maintaining financial stability in the euro area by providing vast liquidity support to commercial banks that are operating in nationally segmented banking systems. As a side effect, the national central banks substitute money market operations for cross-border capital flows. The national central banks are thus increasingly engaging in substantial balance-of-payments financi...

  18. Litterfall and Leaf Area Index in the CONECOFOR Permanent Monitoring Plots

    Directory of Open Access Journals (Sweden)

    Andrea CUTINI

    2002-09-01

    Full Text Available Forest canopies are more sensitive and react more promptly to abiotic and biotic disturbances than other stand structural components. Monitoring crown and canopy characteristics is therefore a crucial issue for intensive and continuous monitoring programs of forest ecosystem status. These observations formed the basis for the measurement of annual litter production and leaf area index (LAI in the Italian permanent monitoring plots (CONECOFOR program established within the EC-UN/ECE program "Intensive Monitoring (Level II of Forest Ecosystems". Preliminary results after three years of observation are presented. The low value of within plot mean relative standard deviation (20.8 ± 1.9% of litter production, which in any case never exceeded 30%, accounted for the good sampling error and accuracy of the chosen method, which seems to be accurate enough to detect changes in litter production through the years. The higher inconsistency of the amount of woody and fruits fractions over the years demonstrated the greater reliability of leaf fraction or, on the other hand, of LAI compared to total litter. Mean values of annual leaf-litter and total litter production and LAI were rather high in comparison with data reported in literature for similar stands, and reflected both a medium-high productivity and a juvenile phase in the development of the selected stands on average. Focusing on changes in litter production through the years, statistical analysis on a sub-sample of plots showed the existence of significant differences both in leaf litter and total litter production. These findings seem to attribute to the "year" factor a driving role in determining changes in litter production and LAI. Temporal intermittence in data collection, together with the shortness of the monitoring period, make it difficult to speculate or arrive at definitive conclusions on changes in litter production due to time-dependent factors. The importance of having a complete

  19. Family differences in equations for predicting biomass and leaf area in Douglas-fir (Pseudotsuga menziesii var. menziesii).

    Science.gov (United States)

    J.B. St. Clair

    1993-01-01

    Logarithmic regression equations were developed to predict component biomass and leaf area for an 18-yr-old genetic test of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) based on stem diameter or cross-sectional sapwood area. Equations did not differ among open-pollinated families in slope, but intercepts...

  20. Leaf-area estimates from spectral measurements over various planting dates of wheat

    Science.gov (United States)

    Hatfield, J. L.; Kanemasu, E. T.; Asrar, G.; Jackson, R. D.; Pinter, P. J., Jr.; Reginato, R. J.; Idso, S. B.

    1985-01-01

    Several vegetative indices were analyzed for their sensitivity and stability to green-leaf-area index (LAI) changes over various planting dates and irrigation frequencies of wheat grown at Phoenix, AZ, from 1978 to 1980. Seasonal patterns of greenness showed that values saturated at LAI values above 4.0 did not return to the pre-emergence bare-soil value at senescence, and were not uniquely related to LAI over the various planting dates. Regressions of individual MSS band reflectances against LAI also showed that there was not a unique relation between any of the bands and LAI. However, the near-infrared/red reflectance ratio was stable over all planting dates and could be used successfully over a number of years and locations.

  1. Estimation of leaf area index in cereal crops using red–green images

    DEFF Research Database (Denmark)

    Nielsen, Kristian Kirk; Andersen, Hans Jørgen; Thomsen, Anton

    2009-01-01

    ,L)-space 2.1.2. Projection of (g,L) and probabilistic labelling 2.1.3. Automatic thresholding procedure 2.2. Gap fraction estimation and inversion 2.3. Experiments 2.3.1. Experiment A 2.3.2. Experiment B 2.3.3. Experiment C 3. Results 3.1. Experiment A 3.2. Experiment B 3.3. Experiment C 4. Discussion 5...... fraction model and an ellipsoidal leaf angle distribution. The LAI estimates were compared with measurements taken using a LAI-2000 Plant Canopy Analyzer in terms of their correlation with results from harvested samples scanned with the LI-3100 Area Meter. The results showed that the method was capable...

  2. Use of remotely sensed precipitation and leaf area index in a distributed hydrological model

    DEFF Research Database (Denmark)

    Andersen, J.; Dybkjær, G.; Jensen, Karsten Høgh

    2002-01-01

    Remotely sensed precipitation from METEOSAT data and leaf area index (LAI) from NOAA AVHRR data is used as input data to the distributed hydrological modelling of three sub catchments (82.000 km(2)) in the Senegal River Basin. Further, root depths of annual vegetation are related to the temporal...... and spatial variation of LAI. The modelling results are compared with results based on conventional input of precipitation and vegetation characteristics. The introduction of remotely sensed LAI shows improvements in the simulated hydrographs, a marked change in the relative proportions of actual...... evapotranspiration comprising canopy evaporation, soil evaporation and transpiration. while no clear trend in the spatial pattern could be found, The remotely sensed precipitation resulted in similar model performances with respect to the simulated hydrographs as with the conventional raingauge input. A simple...

  3. Biomass, Leaf Area, and Resource Availability of Kudzu Dominated Plant Communities Following Herbicide Treatment

    Energy Technology Data Exchange (ETDEWEB)

    L.T. Rader

    2001-10-01

    Kudzu is an exotic vine that threatens the forests of the southern U.S. Five herbicides were tested with regard to their efficacy in controlling kudzu, community recover was monitored, and interactions with planted pines were studied. The sites selected were old farm sites dominated by kudzu.These were burned following herbicide treatment. The herbicides included triclopyr, clopyralid, metsulfuron, tebuthiuron, and picloram plus 2,4-D. Pine seedlings were planted the following year. Regression equations were developed for predicting biomass and leaf area. Four distinct plant communities resulted from the treatments. The untreated check continued to be kudzu dominated. Blackberry dominated the clopyradid treatment. Metsulfron, trychlopyr and picloram treated sites resulted in herbaceous dominated communities. The tebuthiuron treatment maintained all vegetation low.

  4. Leaf Area Index Retrieval Combining HJ1/CCD and Landsat8/OLI Data in the Heihe River Basin, China

    Directory of Open Access Journals (Sweden)

    Jing Zhao

    2015-05-01

    Full Text Available The primary restriction on high resolution remote sensing data is the limit observation frequency. Using a network of multiple sensors is an efficient approach to increase the observations in a specific period. This study explores a leaf area index (LAI inversion method based on a 30 m multi-sensor dataset generated from HJ1/CCD and Landsat8/OLI, from June to August 2013 in the middle reach of the Heihe River Basin, China. The characteristics of the multi-sensor dataset, including the percentage of valid observations, the distribution of observation angles and the variation between different sensor observations, were analyzed. To reduce the possible discrepancy between different satellite sensors on LAI inversion, a quality control system for the observations was designed. LAI is retrieved from the high quality of single-sensor observations based on a look-up table constructed by a unified model. The averaged LAI inversion over a 10-day period is set as the synthetic LAI value. The percentage of valid LAI inversions increases significantly from 6.4% to 49.7% for single-sensors to 75.9% for multi-sensors. LAI retrieved from the multi-sensor dataset show good agreement with the field measurements. The correlation coefficient (R2 is 0.90, and the average root mean square error (RMSE is 0.42. The network of multiple sensors with 30 m spatial resolution can generate LAI products with reasonable accuracy and meaningful temporal resolution.

  5. Retrieval of leaf area index in different plant species using thermal hyperspectral data

    Science.gov (United States)

    Neinavaz, Elnaz; Skidmore, Andrew K.; Darvishzadeh, Roshanak; Groen, Thomas A.

    2016-09-01

    Leaf area index (LAI) is an important variable of terrestrial ecosystems because it is strongly correlated with many ecosystem processes (e.g., water balance and evapotranspiration) and directly related to the plant energy balance and gas exchanges. Although LAI has been accurately predicted using visible and short-wave infrared hyperspectral data (0.3-2.5 μm), LAI estimation using thermal infrared (TIR, 8-14 μm) measurements has not yet been addressed. The novel approach of this study is to evaluate the retrieval of LAI using TIR hyperspectral data. The leaf area indices were destructively acquired for four plant species: Azalea japonica, Buxussempervirens, Euonymus japonicus, and Ficus benjamina. Canopy emissivity spectral measurements were obtained under controlled laboratory conditions using a MIDAC (M4401-F) spectrometer. The LAI retrieval was assessed using a partial least squares regression (PLSR), artificial neural networks (ANNs), and narrow band indices calculated from all possible combinations of waveband pairs for three vegetation indices including simple difference, simple ratio, and normalized difference. ANNs retrieved LAI more accurately than PLSR and vegetation indices (0.67 < R2 < 0.95 versus 11.54% < RMSEcv < 31.23%). The accuracy of LAI retrieval did not differ significantly between the vegetation indices. The results revealed that wavebands from the 8-12 μm region contain relevant information for LAI estimation, irrespective of the chosen vegetation index. Moreover, they demonstrated that LAI may be successfully predicted from TIR hyperspectral data, even for higher values of LAI (LAI ⩾ 5.5). The study showed the significance of using PLSR and ANNs as multivariate methods compared to the univariate technique (e.g., narrow band vegetation indices) when hyperspectral thermal data is utilized. We thus demonstrated for the first time the potential of hyperspectral thermal data to accurately retrieve LAI.

  6. Estimating leaf area index in Southeast Alaska: a comparison of two techniques.

    Directory of Open Access Journals (Sweden)

    Carolyn A Eckrich

    Full Text Available The relationship between canopy structure and light transmission to the forest floor is of particular interest for studying the effects of succession, timber harvest, and silviculture prescriptions on understory plants and trees. Indirect measurements of leaf area index (LAI estimated using gap fraction analysis with linear and hemispheric sensors have been commonly used to assess radiation interception by the canopy, although the two methods often yield inconsistent results. We compared simultaneously obtained measurements of LAI from a linear ceptometer and digital hemispheric photography in 21 forest stands on Prince of Wales Island, Alaska. We assessed the relationship between these estimates and allometric LAI based on tree diameter at breast height (LAIDBH. LAI values measured at 79 stations in thinned, un-thinned controls, old-growth and clearcut stands were highly correlated between the linear sensor (AccuPAR and hemispheric photography, but the latter was more negatively biased compared to LAIDBH. In contrast, AccuPAR values were more similar to LAIDBH in all stands with basal area less than 30 m(2ha(-1. Values produced by integrating hemispheric photographs over the zenith angles 0-75° (Ring 5 were highly correlated with those integrated over the zenith angles 0-60° (Ring 4, although the discrepancies between the two measures were significant. On average, the AccuPAR estimates were 53% higher than those derived from Ring 5, with most of the differences in closed canopy stands (unthinned controls and old-growth and less so in clearcuts. Following typical patterns of canopy closure, AccuPAR LAI values were higher in dense control stands than in old-growth, whereas the opposite was derived from Ring 5 analyses. Based on our results we advocate the preferential use of linear sensors where canopy openness is low, canopies are tall, and leaf distributions are clumped and angles are variable, as is common in the conifer forests of coastal

  7. Simulation of leaf area index on site scale based on model data fusion

    Science.gov (United States)

    Yang, Y.; Wang, J. B.

    2017-12-01

    The world's grassland area is about 24 × 108hm2, accounting for about one-fifth of the global land area. It is one of the most widely distributed terrestrial ecosystems on Earth. And currently, it is the most affected area of human activity. A considerable portion of the global CO2 emissions are fixed by grassland, and the grassland carbon cycle plays an important role in the global carbon cycle (Li Bo, Yongshen Peng, Li Yao, China's Prairie, 1990). In recent years, the carbon cycle and its influencing factors of grassland ecosystems have become one of the hotspots in ecology, geology, botany and agronomy under the background of global change ( Mu Shaojie, 2014) . And the model is now as a popular and effective method of research. However, there are still some uncertainties in this approach. CEVSA ( Carbon Exchange between Vegetation, Soil and Atmosphere) is a biogeochemical cycle model based on physiological and ecological processes to simulate plant-soil-atmosphere system energy exchange and water-carbon-nitrogen coupling cycles (Cao at al., 1998a; 1998b; Woodward et al., 1995). In this paper, the remote sensing observation data of leaf area index are integrated into the model, and the CEVSA model of site version is optimized by Markov chain-Monte Carlo method to achieve the purpose of increasing the accuracy of model results.

  8. Identification of the varietal origin of processed loose-leaf tea based on analysis of a single leaf by SNP nanofluidic array

    Directory of Open Access Journals (Sweden)

    Wanping Fang

    2016-08-01

    Full Text Available Tea is an important cash crop, representing a $40 billion-a-year global market. Differentiation of the tea market has resulted in increasing demand for tea products that are sustainably and responsibly produced. Tea authentication is important because of growing concerns about fraud involving premium tea products. Analytical technologies are needed for protection and value enhancement of high-quality brands. For loose-leaf teas, the challenge is that the authentication needs to be established on the basis of a single leaf, so that the products can be traced back to the original varieties. A new generation of molecular markers offers an ideal solution for authentication of processed agricultural products. Using a nanofluidic array to identify variant SNP sequences, we tested genetic identities using DNA extracted from single leaves of 14 processed commercial tea products. Based on the profiles of 60 SNP markers, the genetic identity of each tea sample was unambiguously identified by multilocus matching and ordination analysis. Results for repeated samples of multiple tea leaves from the same products (using three independent DNA extractions showed 100% concordance, showing that the nanofluidic system is a reliable platform for generating tea DNA fingerprints with high accuracy. The method worked well on green, oolong, and black teas, and can handle a large number of samples in a short period of time. It is robust and cost-effective, thus showing high potential for practical application in the value chain of the tea industry.

  9. Leaf Area Index Estimation Using Chinese GF-1 Wide Field View Data in an Agriculture Region.

    Science.gov (United States)

    Wei, Xiangqin; Gu, Xingfa; Meng, Qingyan; Yu, Tao; Zhou, Xiang; Wei, Zheng; Jia, Kun; Wang, Chunmei

    2017-07-08

    Leaf area index (LAI) is an important vegetation parameter that characterizes leaf density and canopy structure, and plays an important role in global change study, land surface process simulation and agriculture monitoring. The wide field view (WFV) sensor on board the Chinese GF-1 satellite can acquire multi-spectral data with decametric spatial resolution, high temporal resolution and wide coverage, which are valuable data sources for dynamic monitoring of LAI. Therefore, an automatic LAI estimation algorithm for GF-1 WFV data was developed based on the radiative transfer model and LAI estimation accuracy of the developed algorithm was assessed in an agriculture region with maize as the dominated crop type. The radiative transfer model was firstly used to simulate the physical relationship between canopy reflectance and LAI under different soil and vegetation conditions, and then the training sample dataset was formed. Then, neural networks (NNs) were used to develop the LAI estimation algorithm using the training sample dataset. Green, red and near-infrared band reflectances of GF-1 WFV data were used as the input variables of the NNs, as well as the corresponding LAI was the output variable. The validation results using field LAI measurements in the agriculture region indicated that the LAI estimation algorithm could achieve satisfactory results (such as R² = 0.818, RMSE = 0.50). In addition, the developed LAI estimation algorithm had potential to operationally generate LAI datasets using GF-1 WFV land surface reflectance data, which could provide high spatial and temporal resolution LAI data for agriculture, ecosystem and environmental management researches.

  10. Development of monitoring method of coffee leaf rust fungus (Hemileia vastatrix) infected area using satellite remote sensing

    Science.gov (United States)

    Katsuhama, N.; Ikeda, K.; Imai, M.; Watanabe, K.; Marpaung, F.; Yoshii, T.; Naruse, N.; Takahashi, Y.

    2016-12-01

    Since 2008, coffee leaf rust fungus (Hemileia vastatrix) has expanded its infection in Latin America, and early trimming and burning infected trees have been only effective countermeasures to prevent spreading infection. Although some researchers reported a case about the monitoring of coffee leaf rust using satellite remote sensing in 1970s, the spatial resolution was unsatisfied, and therefore, further technological development has been required. The purpose of this research is to develop effective method of discovering coffee leaf rust infected areas using satellite remote sensing. Annual changes of vegetation indices, i.e. Normalized Difference Vegetation Index (NDVI) and Modified Structure Insensitive Pigment Index (MSIPI), around Cuchumatanes Mountains, Republic of Guatemala, were analyzed by Landsat 7 images. Study fields in the research were limited by the coffee farm areas based on a previous paper about on site surveys in different damage areas. As the result of the analysis, the annual change of NDVI at the coffee farm areas with damages tended to be lower than those without damages. Moreover, the decline of NDVI appear from 2008 before the damage was reported. On the other hand, the change of MSIPI had no significant difference. NDVI and MSIPI are mainly related to the amount of chlorophyll and carotenoid in the leaves respectively. This means that the infected coffee leaves turned yellow without defoliation. This situation well matches the symptom of coffee leaf rust. The research concluded that the property of infected leaves turning yellow is effective to monitoring of infection areas by satellite remote sensing.

  11. Sugarcane leaf area estimate obtained from the corrected Normalized Difference Vegetation Index (NDVI

    Directory of Open Access Journals (Sweden)

    Rodrigo Moura Pereira

    2016-06-01

    Full Text Available Large farmland areas and the knowledge on the interaction between solar radiation and vegetation canopies have increased the use of data from orbital remote sensors in sugarcane monitoring. However, the constituents of the atmosphere affect the reflectance values obtained by imaging sensors. This study aimed at improving a sugarcane Leaf Area Index (LAI estimation model, concerning the Normalized Difference Vegetation Index (NDVI subjected to atmospheric correction. The model generated by the NDVI with atmospheric correction showed the best results (R2 = 0.84; d = 0.95; MAE = 0.44; RMSE = 0.55, in relation to the other models compared. LAI estimation with this model, during the sugarcane plant cycle, reached a maximum of 4.8 at the vegetative growth phase and 2.3 at the end of the maturation phase. Thus, the use of atmospheric correction to estimate the sugarcane LAI is recommended, since this procedure increases the correlations between the LAI estimated by image and by plant parameters.

  12. Satellite remote sensing for estimating leaf area index, FPAR and primary production. A literature review

    International Nuclear Information System (INIS)

    Boresjoe Bronge, Laine

    2004-03-01

    Land vegetation is a critical component of several biogeochemical cycles that have become the focus of concerted international research effort. Most ecosystem productivity models, carbon budget models, and global models of climate, hydrology and biogeochemistry require vegetation parameters to calculate land surface photosynthesis, evapotranspiration and net primary production. Therefore, accurate estimates of vegetation parameters are increasingly important in the carbon cycle, the energy balance and in environmental impact assessment studies. The possibility of quantitatively estimating vegetation parameters of importance in this context using satellite data has been explored by numerous papers dealing with the subject. This report gives a summary of the present status and applicability of satellite remote sensing for estimating vegetation productivity by using vegetation index for calculating leaf area index (LAI) and fraction of absorbed photosynthetically active radiation (FPAR). Some possible approaches for use of satellite data for estimating LAI, FPAR and net primary production (NPP) on a local scale are suggested. Recommendations for continued work in the Forsmark and Oskarshamn investigation areas, where vegetation data and NDVI-images based on satellite data have been produced, are also given

  13. ESTIMATES OF THE LEAF AREA INDEX (LAI USING LAI-2000 AND HEMISPHERICAL PHOTOS IN Eucalyptus PLANTATIONS

    Directory of Open Access Journals (Sweden)

    Yhasmin Paiva Rody

    2014-01-01

    Full Text Available The objective of this study was to estimate the Leaf Area Index (LAI by indirect methods in plantations of Eucalyptus clones in two distinct physical-climatic sites, during the dry and rainy periods. The study was performed in four young and adult Eucalyptus stands, located in Rio Doce basin, eastern Minas Gerais state (Brazil situated in areas of lower and higher altitudes. Nine plots were allocated in each stand. Experimental data were collected in months representing the driest and the wettest periods. LAI indirect measurements were performed using the LAI-2000 equipment and cameras with hemispherical lens. To verify the accuracy of estimation, a destructive analysis was also performed. The LAI measurements by the LAI-2000 was the one which best correlated with the observed LAI (R =0.90, although the hemispherical photos had presented good potential use. It is verified that the LAI of stands in the higher altitudes region, surpassed those of lower altitudes, which was also observed by the indirect methods. The destructive analysis indicates lower values of LAI measured in the dry season although this variation is only significant for higher altitudes. This behavior is also observed for estimates with the LAI-2000, different from the hemispherical photographs which did not identify seasonality of LAI.

  14. Measuring Leaf Area in Soy Plants by HSI Color Model Filtering and Mathematical Morphology

    International Nuclear Information System (INIS)

    Benalcázar, M; Padín, J; Brun, M; Pastore, J; Ballarin, V; Peirone, L; Pereyra, G

    2011-01-01

    There has been lately a significant progress in automating tasks for the agricultural sector. One of the advances is the development of robots, based on computer vision, applied to care and management of soy crops. In this task, digital image processing plays an important role, but must solve some important problems, like the ones associated to the variations in lighting conditions during image acquisition. Such variations influence directly on the brightness level of the images to be processed. In this paper we propose an algorithm to segment and measure automatically the leaf area of soy plants. This information is used by the specialists to evaluate and compare the growth of different soy genotypes. This algorithm, based on color filtering using the HSI model, detects green objects from the image background. The segmentation of leaves (foliage) was made applying Mathematical Morphology. The foliage area was estimated counting the pixels that belong to the segmented leaves. From several experiments, consisting in applying the algorithm to measure the foliage of about fifty plants of various genotypes of soy, at different growth stages, we obtained successful results, despite the high brightness variations and shadows in the processed images.

  15. Measuring Leaf Area in Soy Plants by HSI Color Model Filtering and Mathematical Morphology

    Science.gov (United States)

    Benalcázar, M.; Padín, J.; Brun, M.; Pastore, J.; Ballarin, V.; Peirone, L.; Pereyra, G.

    2011-12-01

    There has been lately a significant progress in automating tasks for the agricultural sector. One of the advances is the development of robots, based on computer vision, applied to care and management of soy crops. In this task, digital image processing plays an important role, but must solve some important problems, like the ones associated to the variations in lighting conditions during image acquisition. Such variations influence directly on the brightness level of the images to be processed. In this paper we propose an algorithm to segment and measure automatically the leaf area of soy plants. This information is used by the specialists to evaluate and compare the growth of different soy genotypes. This algorithm, based on color filtering using the HSI model, detects green objects from the image background. The segmentation of leaves (foliage) was made applying Mathematical Morphology. The foliage area was estimated counting the pixels that belong to the segmented leaves. From several experiments, consisting in applying the algorithm to measure the foliage of about fifty plants of various genotypes of soy, at different growth stages, we obtained successful results, despite the high brightness variations and shadows in the processed images.

  16. Satellite remote sensing for estimating leaf area index, FPAR and primary production. A literature review

    Energy Technology Data Exchange (ETDEWEB)

    Boresjoe Bronge, Laine [SwedPower AB, Stockholm (Sweden)

    2004-03-01

    Land vegetation is a critical component of several biogeochemical cycles that have become the focus of concerted international research effort. Most ecosystem productivity models, carbon budget models, and global models of climate, hydrology and biogeochemistry require vegetation parameters to calculate land surface photosynthesis, evapotranspiration and net primary production. Therefore, accurate estimates of vegetation parameters are increasingly important in the carbon cycle, the energy balance and in environmental impact assessment studies. The possibility of quantitatively estimating vegetation parameters of importance in this context using satellite data has been explored by numerous papers dealing with the subject. This report gives a summary of the present status and applicability of satellite remote sensing for estimating vegetation productivity by using vegetation index for calculating leaf area index (LAI) and fraction of absorbed photosynthetically active radiation (FPAR). Some possible approaches for use of satellite data for estimating LAI, FPAR and net primary production (NPP) on a local scale are suggested. Recommendations for continued work in the Forsmark and Oskarshamn investigation areas, where vegetation data and NDVI-images based on satellite data have been produced, are also given.

  17. Assimilating a synthetic Kalman filter leaf area index series into the WOFOST model to improve regional winter wheat yield estimation

    Science.gov (United States)

    The scale mismatch between remotely sensed observations and crop growth models simulated state variables decreases the reliability of crop yield estimates. To overcome this problem, we used a two-step data assimilation phases: first we generated a complete leaf area index (LAI) time series by combin...

  18. Monthly leaf area index estimates from point-in-time measurements and needle phenology for Pinus taeda

    Science.gov (United States)

    D.A. Sampson; T.J. Albaugh; Kurt H. Johnsen; H.L. Allen; Stanley J. Zarnoch

    2003-01-01

    Abstract: Leaf area index (LAI) of loblolly pine (Pinus taeda L.) trees of the southern United States varies almost twofold interannually; loblolly pine, essentially, carries two foliage cohorts at peak LAI (September) and one at minimum (March–April). Herein, we present an approach that may be site invariant to estimate monthly...

  19. Leaf area index estimation with MODIS reflectance time series and model inversion during full rotations of Eucalyptus plantations

    NARCIS (Netherlands)

    Maire, Le G.; Marsden, C.; Verhoef, W.; Ponzoni, F.J.; Seen, Lo D.; Bégué, A.; Stape, J.L.; Nouvellon, Y.

    2011-01-01

    The leaf area index (LAI) of fast-growing Eucalyptus plantations is highly dynamic both seasonally and inter-annually, and is spatially variable depending on pedo-climatic conditions. LAI is very important in determining the carbon and water balance of a stand, but is difficult to measure during a

  20. Leaf area and structural changes after thinning in even-aged Picea rubens and Abies balsamea stands in Maine, USA

    Science.gov (United States)

    R. Justin DeRose; Robert S. Seymour

    2012-01-01

    We tested the hypothesis that changes in leaf area index (LAIm2 m-2) and mean stand diameter following thinning are due to thinning type and residual density. The ratios of pre- to postthinning diameter and LAI were used to assess structural changes between replicated crown, dominant, and low thinning treatments to 33% and 50% residual density in even-aged Picea rubens...

  1. Benchmarking sensitivity of biophysical processes to leaf area changes in land surface models

    Science.gov (United States)

    Forzieri, Giovanni; Duveiller, Gregory; Georgievski, Goran; Li, Wei; Robestson, Eddy; Kautz, Markus; Lawrence, Peter; Ciais, Philippe; Pongratz, Julia; Sitch, Stephen; Wiltshire, Andy; Arneth, Almut; Cescatti, Alessandro

    2017-04-01

    Land surface models (LSM) are widely applied as supporting tools for policy-relevant assessment of climate change and its impact on terrestrial ecosystems, yet knowledge of their performance skills in representing the sensitivity of biophysical processes to changes in vegetation density is still limited. This is particularly relevant in light of the substantial impacts on regional climate associated with the changes in leaf area index (LAI) following the observed global greening. Benchmarking LSMs on the sensitivity of the simulated processes to vegetation density is essential to reduce their uncertainty and improve the representation of these effects. Here we present a novel benchmark system to assess model capacity in reproducing land surface-atmosphere energy exchanges modulated by vegetation density. Through a collaborative effort of different modeling groups, a consistent set of land surface energy fluxes and LAI dynamics has been generated from multiple LSMs, including JSBACH, JULES, ORCHIDEE, CLM4.5 and LPJ-GUESS. Relationships of interannual variations of modeled surface fluxes to LAI changes have been analyzed at global scale across different climatological gradients and compared with satellite-based products. A set of scoring metrics has been used to assess the overall model performances and a detailed analysis in the climate space has been provided to diagnose possible model errors associated to background conditions. Results have enabled us to identify model-specific strengths and deficiencies. An overall best performing model does not emerge from the analyses. However, the comparison with other models that work better under certain metrics and conditions indicates that improvements are expected to be potentially achievable. A general amplification of the biophysical processes mediated by vegetation is found across the different land surface schemes. Grasslands are characterized by an underestimated year-to-year variability of LAI in cold climates

  2. Interannual variation in leaf photosynthetic capacity during summer in relation to nitrogen, leaf mass per area and climate within a Fagus crenata crown on Naeba Mountain, Japan.

    Science.gov (United States)

    Iio, Atsuhiro; Yokoyama, Akira; Takano, Masamitsu; Nakamura, Tetsurou; Fukasawa, Hisakazu; Nose, Yachiho; Kakubari, Yoshitaka

    2008-09-01

    During the summers (July and August) of 2002-2005, we measured interannual variation in maximum carboxylation rate (V(cmax)) within a Fagus crenata Blume crown in relation to climate variables such as air temperature, daytime vapor pressure deficit (VPD) and daily photosynthetic photon flux, leaf nitrogen per unit area (N(a)) and leaf mass per unit area (LMA). Climatic conditions in the summers of 2002-2004 differed markedly, with warm and dry atmospheric conditions in 2002, cool, humid and cloudy conditions in 2003, and warm clear conditions in 2004. Conditions in summer 2005 were intermediate between those of summers 2002 and 2003, and similar to recent (8-year) means. In July, marked interannual variation in V(cmax) was mainly observed in leaves in the high-light environment (relative photon flux > 50%) within the crown. At the crown top, V(cmax) was about twofold higher in 2002 than in 2003, and V(cmax) values in 2004 and 2005 were intermediate between those in 2002 and 2003. In August, although interannual variation in V(cmax) among the years 2003, 2004 and 2005 was less, marked variation between 2002 and the other study years was evident. Multiple regression analysis of V(cmax) against the climate variables revealed that VPD of the previous 10-30 days had a significant influence on variability in V(cmax). Neither N(a), LMA nor leaf CO(2) conductance from the stomata to the carboxylation site explained the variability in V(cmax). Our results indicate that the long-term climatic response of V(cmax) should be considered when estimating forest carbon gain across the year.

  3. Allometric relationships predicting foliar biomass and leaf area:sapwood area ratio from tree height in five Costa Rican rain forest species.

    Science.gov (United States)

    Calvo-Alvarado, J C; McDowell, N G; Waring, R H

    2008-11-01

    We developed allometric equations to predict whole-tree leaf area (A(l)), leaf biomass (M(l)) and leaf area to sapwood area ratio (A(l):A(s)) in five rain forest tree species of Costa Rica: Pentaclethra macroloba (Willd.) Kuntze (Fabaceae/Mim), Carapa guianensis Aubl. (Meliaceae), Vochysia ferru-gi-nea Mart. (Vochysiaceae), Virola koshnii Warb. (Myristicaceae) and Tetragastris panamensis (Engl.) Kuntze (Burseraceae). By destructive analyses (n = 11-14 trees per species), we observed strong nonlinear allometric relationships (r(2) > or = 0.9) for predicting A(l) or M(l) from stem diameters or A(s) measured at breast height. Linear relationships were less accurate. In general, A(l):A(s) at breast height increased linearly with tree height except for Penta-clethra, which showed a negative trend. All species, however, showed increased total A(l) with height. The observation that four of the five species increased in A(l):A(s) with height is consistent with hypotheses about trade--offs between morphological and anatomical adaptations that favor efficient water flow through variation in the amount of leaf area supported by sapwood and those imposed by the need to respond quickly to light gaps in the canopy.

  4. A Comparison of Simulated and Field-Derived Leaf Area Index (LAI) and Canopy Height Values from Four Forest Complexes in the Southeastern USA

    Science.gov (United States)

    Vegetative leaf area is a critical input to models that simulate human and ecosystem exposure to atmospheric pollutants. Leaf area index (LAI) can be measured in the field or numerically simulated, but all contain some inherent uncertainty that is passed to the exposure assessmen...

  5. Measurements and simulation of forest leaf area index and net primary productivity in Northern China.

    Science.gov (United States)

    Wang, P; Sun, R; Hu, J; Zhu, Q; Zhou, Y; Li, L; Chen, J M

    2007-11-01

    Large scale process-based modeling is a useful approach to estimate distributions of global net primary productivity (NPP). In this paper, in order to validate an existing NPP model with observed data at site level, field experiments were conducted at three sites in northern China. One site is located in Qilian Mountain in Gansu Province, and the other two sites are in Changbaishan Natural Reserve and Dunhua County in Jilin Province. Detailed field experiments are discussed and field data are used to validate the simulated NPP. Remotely sensed images including Landsat Enhanced Thematic Mapper plus (ETM+, 30 m spatial resolution in visible and near infrared bands) and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER, 15m spatial resolution in visible and near infrared bands) are used to derive maps of land cover, leaf area index, and biomass. Based on these maps, field measured data, soil texture and daily meteorological data, NPP of these sites are simulated for year 2001 with the boreal ecosystem productivity simulator (BEPS). The NPP in these sites ranges from 80 to 800 gCm(-2)a(-1). The observed NPP agrees well with the modeled NPP. This study suggests that BEPS can be used to estimate NPP in northern China if remotely sensed images of high spatial resolution are available.

  6. Relationships of Leaf Area Index and NDVI for 12 Brassica Cultivars in Northeastern Montana

    Science.gov (United States)

    Jabro, Jay; Allen, Brett; Long, Dan; Isbell, Terry; Gesch, Russ; Brown, Jack; Hatfield, Jerry; Archer, David; Oblath, Emily; Vigil, Merle; Kiniry, Jim; Hunter, Kimberly; Shonnard, David

    2017-04-01

    To our knowledge, there is limited information on the relationship of the normalized difference vegetation index (NDVI) and leaf area index (LAI) in spring Brassica oilseed crops. The 2014 results of NDVI and LAI of 12 spring varieties of oilseed crops were measured in a field study conducted in Sidney, Montana, USA under dryland conditions. These 12 varieties were grouped under six species (B. napus, B. rapa, B. juncea, B. carinata, Sinapis alba, and Camelina sativa). The NDVI and LAI were measured weekly throughout the growing season. The NDVI was continually measured at one sample per second across the whole plot using a Crop Circle ACS-470 active crop canopy sensor. The LAI was measured at two locations at 12 samples per plot using an AccuPar model LP-80 Ceptometer. Treatments were replicated four times in a randomized complete block design in plots of 3 m×9 m. Temporal dynamics of NDVI and LAI in various growth stages of 12 varieties were evaluated throughout the growing season. Significant relationships and models between NDVI and LAI were obtained when 12 varieties were grouped under six species.

  7. Evaluation of Three Techniques for Correcting the Spatial Scaling Bias of Leaf Area Index

    Directory of Open Access Journals (Sweden)

    Jiale Jiang

    2018-02-01

    Full Text Available The correction of spatial scaling bias on the estimate of leaf area index (LAI retrieved from remotely sensed data is an essential issue in quantitative remote sensing for vegetation monitoring. We analyzed three techniques, including Taylor’s theorem (TT, Wavelet-Fractal technique (WF, and Fractal theory (FT, for correcting the scaling bias of LAI with empirical models in different functions (i.e., power, exponential, logarithmic and polynomial on both simulated data and a real dataset over a cropland site. The results demonstrated that the scaling bias became greater when the model non-linearity increased. The spatial heterogeneity, which was characterized by the class-specific proportion, the between-class spectral difference and the number of classes within each coarse pixel, was found to be the primary factor in the scaling effect. These factors influenced the scaling effect collectively and existed dependently. With the RMSE less than 0.3 × 10−6 m2/m2, TT was suggested for the correction with a polynomial LAI-NDVI functions. WF was preferred for neighboring scales rather than continuous scales. FT was not recommended for correcting the scaling bias caused by the significant non-linearity in LAI estimation models. This study illustrates the main causes of the scaling effect and provides a reference of technique selection for scaling bias correction to improve the application of remotely sensed estimates.

  8. Estimating the Fractional Vegetation Cover from GLASS Leaf Area Index Product

    Directory of Open Access Journals (Sweden)

    Zhiqiang Xiao

    2016-04-01

    Full Text Available The fractional vegetation cover (FCover is an essential biophysical variable and plays a critical role in the carbon cycle studies. Existing FCover products from satellite observations are spatially incomplete and temporally discontinuous, and also inaccurate for some vegetation types to meet the requirements of various applications. In this study, an operational method is proposed to calculate high-quality, accurate FCover from the Global LAnd Surface Satellite (GLASS leaf area index (LAI product to ensure physical consistency between LAI and FCover retrievals. As a result, a global FCover product (denoted by TRAGL were generated from the GLASS LAI product from 2000 to present. With no missing values, the TRAGL FCover product is spatially complete. A comparison of the TRAGL FCover product with the Geoland2/BioPar version 1 (GEOV1 FCover product indicates that these FCover products exhibit similar spatial distribution pattern. However, there were relatively large discrepancies between these FCover products over equatorial rainforests, broadleaf crops in East-central United States, and needleleaf forests in Europe and Siberia. Temporal consistency analysis indicates that TRAGL FCover product has continuous trajectories. Direct validation with ground-based FCover estimates demonstrated that TRAGL FCover values were more accurate (RMSE = 0.0865, and R2 = 0.8848 than GEOV1 (RMSE = 0.1541, and R2 = 0.7621.

  9. Continuous measurement of leaf area index (LAI) over broadleaf crop fields in northeast China

    Science.gov (United States)

    Fang, H.; Ye, Y.; Liu, W.; Wei, S.; Ma, L.

    2017-12-01

    Leaf area index (LAI) is one of the essential climate variables used in many ecological and land surface process models. Global LAI products have been provided routinely by many remote sensing projects. Reliable and consistent LAI estimates are a priority for LAI validation study and the application communities. In situ LAI measurements are a critical component of our ongoing global LAI validation efforts. Automatic methods, e.g., PASTIS-57, and smartphone applications (APPs) have become increasingly available for efficient field LAI measurements. The objective of this study is to investigate the feasibility of automatic and portable smartphone LAI measurements together with traditional indirect optical LAI measurements. A seasonal field campaign was carried out to take continuous LAI measurements over corn, soybean, and sorghum fields in northeast China in 2016. Field LAI measurement was made with the automatic PASTIS-57, two smartphone applications, PocketLAI and LAISmart, and two handheld optical instruments, LAI-2200 and digital hemispherical photography (DHP). The results show that PASTIS-57 provides a convenient and accurate LAI estimation method as compared to LAI-2200 and DHP. LAI estimates from smartphone applications are generally smaller than the LAI-2200 and DHP values. In addition to the LAI measurements, continuous clumping index (CI) measurements were also obtained. The seasonal continuous LAI and CI measurements obtained from this study are valuable for the validation of remote sensing products.

  10. Optimal Exploitation of the Sentinel-2 Spectral Capabilities for Crop Leaf Area Index Mapping

    Directory of Open Access Journals (Sweden)

    Guido D’Urso

    2012-02-01

    Full Text Available The continuously increasing demand of accurate quantitative high quality information on land surface properties will be faced by a new generation of environmental Earth observation (EO missions. One current example, associated with a high potential to contribute to those demands, is the multi-spectral ESA Sentinel-2 (S2 system. The present study focuses on the evaluation of spectral information content needed for crop leaf area index (LAI mapping in view of the future sensors. Data from a field campaign were used to determine the optimal spectral sampling from available S2 bands applying inversion of a radiative transfer model (PROSAIL with look-up table (LUT and artificial neural network (ANN approaches. Overall LAI estimation performance of the proposed LUT approach (LUTN50 was comparable in terms of retrieval performances with a tested and approved ANN method. Employing seven- and eight-band combinations, the LUTN50 approach obtained LAI RMSE of 0.53 and normalized LAI RMSE of 0.12, which was comparable to the results of the ANN. However, the LUTN50 method showed a higher robustness and insensitivity to different band settings. Most frequently selected wavebands were located in near infrared and red edge spectral regions. In conclusion, our results emphasize the potential benefits of the Sentinel-2 mission for agricultural applications.

  11. LEAF AREA INDEX DERIVED FROM HEMISPHERICAL PHOTOGRAPH AND ITS CORRELATION WITH ABOVEGROUND FOREST BIOMASS

    Directory of Open Access Journals (Sweden)

    Tyas Mutiara Basuki

    2015-04-01

    Full Text Available Leaf area index (LAI is one of the key physical factors in the energy exchange between terrestrial ecosystem and atmosphere. It determines the photosynthesis process to produce biomass and plays an important role in performing forest stand reflectance. Therefore building relationship between LAI and biomass from field measurements can be used to develop allometric equations for biomass estimation. This paper studies the relationship between diameter at breast height (DBH and leaves biomass, DBH and crown biomass (sum up of leaves, twigs and branches as well as between LAI and leaves biomass; LAI and crown biomass; LAI and Total Above-ground Biomass (TAGB in East Kalimantan Province. Destructive sampling was conducted to develop allometric equations. The DBH measurements from 52 sample plots were used as training data for model development (35 plots and for validation (17 plots. A hemispherical photograph was used to record LAI. The result shows that strong corelation (r exists between natural logarithmic (ln DBH and crown biomass ranging from 0.88 to 0.98. The correlation (r between LAI and biomass of leaves; leaves + twigs + branches; TAGB were 0.742, 0.768 and 0.772, respectively. Improvement of (r between LAI and biomass can be conducted by proper time of LAI measurement, when the sky is uniformly overcast.

  12. Relationships between NDVI and Leaf Area Index for spring and winter camelina in Northeastern Montana

    Science.gov (United States)

    Jabro, Jay; Allen, Brett; long, Dan; Isbell, Terry; Gesch, Russ; Brown, Jack; Hatfield, Jerry; Archer, David; Oblath, Emily; Vigil, Merle; Kiniry, Jim

    2016-04-01

    To our knowledge no research has been reported on the relationship between the normalized difference vegetation index (NDVI) and leaf area index (LAI) in spring and winter camelina. Relationships between NDVI and LAI for winter camelina (Camelina sativa) "Joelle" and spring camelina "CO46" were determined and evaluated in a 3-yr field study conducted in Sidney Montana under dryland conditions. The NDVI and LAI were measured weekly throughout the growing season. The NDVI was continually measured at one sample per second across the whole plot using a Crop Circle ACS-470 active crop canopy sensor. The LAI was measured at two locations at 12 samples per plot using an AccuPar model LP-80 Ceptometer. Treatments were replicated four times in a randomized complete block design in plots of 3 m×9 m. Temporal dynamics of NDVI and LAI in various growth stages of both spring and winter camelina were evaluated throughout 2013, 2014 and 2015 growing seasons. Significant linear relationships between NDVI and LAI were obtained for both spring and winter camelina when all the measurements were pooled across three growing seasons. Coefficients of determination (R2) of linearity were 0.77 and 0.79 for spring and winter camelina, respectively.

  13. Detection of the Coupling between Vegetation Leaf Area and Climate in a Multifunctional Watershed, Northwestern China

    Directory of Open Access Journals (Sweden)

    Lu Hao

    2016-12-01

    Full Text Available Accurate detection and quantification of vegetation dynamics and drivers of observed climatic and anthropogenic change in space and time is fundamental for our understanding of the atmosphere–biosphere interactions at local and global scales. This case study examined the coupled spatial patterns of vegetation dynamics and climatic variabilities during the past three decades in the Upper Heihe River Basin (UHRB, a complex multiple use watershed in arid northwestern China. We apply empirical orthogonal function (EOF and singular value decomposition (SVD analysis to isolate and identify the spatial patterns of satellite-derived leaf area index (LAI and their close relationship with the variability of an aridity index (AI = Precipitation/Potential Evapotranspiration. Results show that UHRB has become increasingly warm and wet during the past three decades. In general, the rise of air temperature and precipitation had a positive impact on mean LAI at the annual scale. At the monthly scale, LAI variations had a lagged response to climate. Two major coupled spatial change patterns explained 29% and 41% of the LAI dynamics during 1983–2000 and 2001–2010, respectively. The strongest connections between climate and LAI were found in the southwest part of the basin prior to 2000, but they shifted towards the north central area afterwards, suggesting that the sensitivity of LAI to climate varied over time, and that human disturbances might play an important role in altering LAI patterns. At the basin level, the positive effects of regional climate warming and precipitation increase as well as local ecological restoration efforts overwhelmed the negative effects of overgrazing. The study results offer insights about the coupled effects of climatic variability and grazing on ecosystem structure and functions at a watershed scale. Findings from this study are useful for land managers and policy makers to make better decisions in response to climate

  14. Mapping canopy gap fraction and leaf area index at continent-scale from satellite lidar

    Science.gov (United States)

    Mahoney, C.; Hopkinson, C.; Held, A. A.

    2015-12-01

    Information on canopy cover is essential for understanding spatial and temporal variability in vegetation biomass, local meteorological processes and hydrological transfers within vegetated environments. Gap fraction (GF), an index of canopy cover, is often derived over large areas (100's km2) via airborne laser scanning (ALS), estimates of which are reasonably well understood. However, obtaining country-wide estimates is challenging due to the lack of spatially distributed point cloud data. The Geoscience Laser Altimeter System (GLAS) removes spatial limitations, however, its large footprint nature and continuous waveform data measurements make derivations of GF challenging. ALS data from 3 Australian sites are used as a basis to scale-up GF estimates to GLAS footprint data by the use of a physically-based Weibull function. Spaceborne estimates of GF are employed in conjunction with supplementary predictor variables in the predictive Random Forest algorithm to yield country-wide estimates at a 250 m spatial resolution; country-wide estimates are accompanied with uncertainties at the pixel level. Preliminary estimates of effective Leaf Area Index (eLAI) are also presented by converting GF via the Beer-Lambert law, where an extinction coefficient of 0.5 is employed; deemed acceptable at such spatial scales. The need for such wide-scale quantification of GF and eLAI are key in the assessment and modification of current forest management strategies across Australia. Such work also assists Australia's Terrestrial Ecosystem Research Network (TERN), a key asset to policy makers with regards to the management of the national ecosystem, in fulfilling their government issued mandates.

  15. Teratosphaeria nubilosa, a serious leaf disease pathogen of Eucalyptus spp. in native and introduced areas

    NARCIS (Netherlands)

    Hunter, G.C.; Crous, P.W.; Carnegie, A.J.; Wingfield, M.J.

    2009-01-01

    Teratosphaeria nubilosa is a serious leaf pathogen of several Eucalyptus spp. This review considers the taxonomic history, epidemiology, host associations and molecular biology of T. nubilosa. Kingdom Fungi; Phylum Ascomycota; Class Dothideomycetes; Order Capnodiales; Family Teratosphaeriaceae;

  16. Teratosphaeria nubilosa, a serious leaf disease pathogen of Eucalyptus spp. in native and introduced areas

    NARCIS (Netherlands)

    Hunter, G.C.; Crous, P.W.; Carnegie, A.J.; Wingfield, M.J.

    2009-01-01

    BACKGROUND: Teratosphaeria nubilosa is a serious leaf pathogen of several Eucalyptus spp. This review considers the taxonomic history, epidemiology, host associations and molecular biology of T. nubilosa. TAXONOMY: Kingdom Fungi; Phylum Ascomycota; Class Dothideomycetes; Order Capnodiales; Family

  17. Effective leaf area index retrieving from terrestrial point cloud data: coupling computational geometry application and Gaussian mixture model clustering

    Science.gov (United States)

    Jin, S.; Tamura, M.; Susaki, J.

    2014-09-01

    Leaf area index (LAI) is one of the most important structural parameters of forestry studies which manifests the ability of the green vegetation interacted with the solar illumination. Classic understanding about LAI is to consider the green canopy as integration of horizontal leaf layers. Since multi-angle remote sensing technique developed, LAI obliged to be deliberated according to the observation geometry. Effective LAI could formulate the leaf-light interaction virtually and precisely. To retrieve the LAI/effective LAI from remotely sensed data therefore becomes a challenge during the past decades. Laser scanning technique can provide accurate surface echoed coordinates with densely scanned intervals. To utilize the density based statistical algorithm for analyzing the voluminous amount of the 3-D points data is one of the subjects of the laser scanning applications. Computational geometry also provides some mature applications for point cloud data (PCD) processing and analysing. In this paper, authors investigated the feasibility of a new application for retrieving the effective LAI of an isolated broad leaf tree. Simplified curvature was calculated for each point in order to remove those non-photosynthetic tissues. Then PCD were discretized into voxel, and clustered by using Gaussian mixture model. Subsequently the area of each cluster was calculated by employing the computational geometry applications. In order to validate our application, we chose an indoor plant to estimate the leaf area, the correlation coefficient between calculation and measurement was 98.28 %. We finally calculated the effective LAI of the tree with 6 × 6 assumed observation directions.

  18. Integrating remotely sensed leaf area index and leaf nitrogen accumulation with RiceGrow model based on particle swarm optimization algorithm for rice grain yield assessment

    Science.gov (United States)

    Wang, Hang; Zhu, Yan; Li, Wenlong; Cao, Weixing; Tian, Yongchao

    2014-01-01

    A regional rice (Oryza sativa) grain yield prediction technique was proposed by integration of ground-based and spaceborne remote sensing (RS) data with the rice growth model (RiceGrow) through a new particle swarm optimization (PSO) algorithm. Based on an initialization/parameterization strategy (calibration), two agronomic indicators, leaf area index (LAI) and leaf nitrogen accumulation (LNA) remotely sensed by field spectra and satellite images, were combined to serve as an external assimilation parameter and integrated with the RiceGrow model for inversion of three model management parameters, including sowing date, sowing rate, and nitrogen rate. Rice grain yield was then predicted by inputting these optimized parameters into the reinitialized model. PSO was used for the parameterization and regionalization of the integrated model and compared with the shuffled complex evolution-University of Arizona (SCE-UA) optimization algorithm. The test results showed that LAI together with LNA as the integrated parameter performed better than each alone for crop model parameter initialization. PSO also performed better than SCE-UA in terms of running efficiency and assimilation results, indicating that PSO is a reliable optimization method for assimilating RS information and the crop growth model. The integrated model also had improved precision for predicting rice grain yield.

  19. Area detectors in single-crystal neutron diffraction

    Science.gov (United States)

    McIntyre, Garry J.

    2015-12-01

    The introduction of area detectors has brought about a gentle revolution in the routine application of single-crystal neutron diffractometry. Implemented first for macromolecular crystallography, electronic detectors subsequently gradually spread to chemical and physics-oriented crystallography at steady-state sources. The volumetric surveying of reciprocal space implicit in the Laue technique has required area detectors right from the start, whether using film and more recently image plates and CCD-based detectors at reactors, or scintillation detectors at spallation sources. Wide-angle volumetric data collection has extended application of neutron single-crystal diffractometry to chemical structures, sample volumes, and physical phenomena previously deemed impossible. More than 30 of the dedicated single-crystal neutron diffractometers at steady-state reactor and neutron spallation sources worldwide and accessible via peer-review proposal mechanisms are currently equipped with area detectors. Here we review the historical development of the various types of area detectors used for single crystals, discuss experimental aspects peculiar to experiments with such detectors, highlight the scientific fields where the use of area detectors has had a special impact, and forecast future developments in hardware, implementation, and software.

  20. Area detectors in single-crystal neutron diffraction

    International Nuclear Information System (INIS)

    McIntyre, Garry J

    2015-01-01

    The introduction of area detectors has brought about a gentle revolution in the routine application of single-crystal neutron diffractometry. Implemented first for macromolecular crystallography, electronic detectors subsequently gradually spread to chemical and physics-oriented crystallography at steady-state sources. The volumetric surveying of reciprocal space implicit in the Laue technique has required area detectors right from the start, whether using film and more recently image plates and CCD-based detectors at reactors, or scintillation detectors at spallation sources. Wide-angle volumetric data collection has extended application of neutron single-crystal diffractometry to chemical structures, sample volumes, and physical phenomena previously deemed impossible. More than 30 of the dedicated single-crystal neutron diffractometers at steady-state reactor and neutron spallation sources worldwide and accessible via peer-review proposal mechanisms are currently equipped with area detectors. Here we review the historical development of the various types of area detectors used for single crystals, discuss experimental aspects peculiar to experiments with such detectors, highlight the scientific fields where the use of area detectors has had a special impact, and forecast future developments in hardware, implementation, and software. (review)

  1. Generating Global Leaf Area Index from Landsat: Algorithm Formulation and Demonstration

    Science.gov (United States)

    Ganguly, Sangram; Nemani, Ramakrishna R.; Zhang, Gong; Hashimoto, Hirofumi; Milesi, Cristina; Michaelis, Andrew; Wang, Weile; Votava, Petr; Samanta, Arindam; Melton, Forrest; hide

    2012-01-01

    This paper summarizes the implementation of a physically based algorithm for the retrieval of vegetation green Leaf Area Index (LAI) from Landsat surface reflectance data. The algorithm is based on the canopy spectral invariants theory and provides a computationally efficient way of parameterizing the Bidirectional Reflectance Factor (BRF) as a function of spatial resolution and wavelength. LAI retrievals from the application of this algorithm to aggregated Landsat surface reflectances are consistent with those of MODIS for homogeneous sites represented by different herbaceous and forest cover types. Example results illustrating the physics and performance of the algorithm suggest three key factors that influence the LAI retrieval process: 1) the atmospheric correction procedures to estimate surface reflectances; 2) the proximity of Landsatobserved surface reflectance and corresponding reflectances as characterized by the model simulation; and 3) the quality of the input land cover type in accurately delineating pure vegetated components as opposed to mixed pixels. Accounting for these factors, a pilot implementation of the LAI retrieval algorithm was demonstrated for the state of California utilizing the Global Land Survey (GLS) 2005 Landsat data archive. In a separate exercise, the performance of the LAI algorithm over California was evaluated by using the short-wave infrared band in addition to the red and near-infrared bands. Results show that the algorithm, while ingesting the short-wave infrared band, has the ability to delineate open canopies with understory effects and may provide useful information compared to a more traditional two-band retrieval. Future research will involve implementation of this algorithm at continental scales and a validation exercise will be performed in evaluating the accuracy of the 30-m LAI products at several field sites. ©

  2. Analysis of Differences in Phenology Extracted from the Enhanced Vegetation Index and the Leaf Area Index.

    Science.gov (United States)

    Wang, Cong; Li, Jing; Liu, Qinhuo; Zhong, Bo; Wu, Shanlong; Xia, Chuanfu

    2017-08-30

    Remote-sensing phenology detection can compensate for deficiencies in field observations and has the advantage of capturing the continuous expression of phenology on a large scale. However, there is some variability in the results of remote-sensing phenology detection derived from different vegetation parameters in satellite time-series data. Since the enhanced vegetation index (EVI) and the leaf area index (LAI) are the most widely used vegetation parameters for remote-sensing phenology extraction, this paper aims to assess the differences in phenological information extracted from EVI and LAI time series and to explore whether either index performs well for all vegetation types on a large scale. To this end, a GLASS (Global Land Surface Satellite Product)-LAI-based phenology product (GLP) was generated using the same algorithm as the MODIS (Moderate Resolution Imaging Spectroradiometer)-EVI phenology product (MLCD) over China from 2001 to 2012. The two phenology products were compared in China for different vegetation types and evaluated using ground observations. The results show that the ratio of missing data is 8.3% for the GLP, which is less than the 22.8% for the MLCD. The differences between the GLP and the MLCD become stronger as the latitude decreases, which also vary among different vegetation types. The start of the growing season (SOS) of the GLP is earlier than that of the MLCD in most vegetation types, and the end of the growing season (EOS) of the GLP is generally later than that of the MLCD. Based on ground observations, it can be suggested that the GLP performs better than the MLCD in evergreen needleleaved forests and croplands, while the MLCD performs better than the GLP in shrublands and grasslands.

  3. A method for assessing intercepted radiation by a crop with a low leaf area: an application to oilseed rape

    International Nuclear Information System (INIS)

    Denoroy, P.; Thiebeau, P.; Gosse, G.

    2002-01-01

    Calculation of photosynthetically active radiation interception by a crop with a low leaf area index, particularly when the canopy is not closed, needs a more detailed approach than a simple Beer's law with constant light extinction coefficient (k). This paper introduces a simple procedure for the calculation of intercepted radiation, taking into account the ground cover ratio, and using a small set of parameters. The k coefficient is deduced from this calculation and we show that k depends on the leaf area index, the location and the season. The significance of introducing ground cover ratio in the calculation of intercepted radiation is estimated, and sensitivity of the method to various parameters is assessed [fr

  4. Mapping Vineyard Leaf Area Using Mobile Terrestrial Laser Scanners: Should Rows be Scanned On-the-Go or Discontinuously Sampled?

    Directory of Open Access Journals (Sweden)

    Ignacio del-Moral-Martínez

    2016-01-01

    Full Text Available The leaf area index (LAI is defined as the one-side leaf area per unit ground area, and is probably the most widely used index to characterize grapevine vigor. However, LAI varies spatially within vineyard plots. Mapping and quantifying this variability is very important for improving management decisions and agricultural practices. In this study, a mobile terrestrial laser scanner (MTLS was used to map the LAI of a vineyard, and then to examine how different scanning methods (on-the-go or discontinuous systematic sampling may affect the reliability of the resulting raster maps. The use of the MTLS allows calculating the enveloping vegetative area of the canopy, which is the sum of the leaf wall areas for both sides of the row (excluding gaps and the projected upper area. Obtaining the enveloping areas requires scanning from both sides one meter length section along the row at each systematic sampling point. By converting the enveloping areas into LAI values, a raster map of the latter can be obtained by spatial interpolation (kriging. However, the user can opt for scanning on-the-go in a continuous way and compute 1-m LAI values along the rows, or instead, perform the scanning at discontinuous systematic sampling within the plot. An analysis of correlation between maps indicated that MTLS can be used discontinuously in specific sampling sections separated by up to 15 m along the rows. This capability significantly reduces the amount of data to be acquired at field level, the data storage capacity and the processing power of computers.

  5. Structural characteristics and forage mass of Tifton 85 pastures managed under three post-grazing residual leaf areas

    Directory of Open Access Journals (Sweden)

    Wilton Ladeira da Silva

    2013-04-01

    Full Text Available The experiment was carried out on Cynodon spp cv. Tifton 85 pastures grazed by sheep under rotational stocking, with the objective of evaluating the structural characteristics as well as the forage mass of the pastures subjected to three grazing intensities in successive cycles. Treatments were composed of three residual leaf area indices (rLAI; 2.4; 1.6 and 0.8, allocated in completely randomized blocks with seven replications, totaling 21 experimental units. Tiller population density, pasture height, leaf area index, forage morphological composition and pasture forage mass were evaluated. The rLAI modified the tiller population density, which increased linearly with decrease in the rLAI of the pastures. Dry masses of leaf blade, stem and dead material were inferior when the rLAI imposed were lower, which resulted in differentiated forage production among the treatments. Tifton 85 pastures grazed by sheep in rotational stocking under tropical conditions with different rLAI show a modified sward structure over successive grazing cycles, mainly by alteration in the height and LAI of the plants at pre-grazing and by light interception post-grazing, which change the tiller population density. The residual leaf area index of 1.6 is the most suitable for pasture management for being equivalent to the heights of entrance and exit of animals on and from paddocks of 33 and 19 cm, respectively, which avoid great accumulation of dead material and excessive stem elongation, in addition to ensuring tillering in the sward.

  6. Seasonal variation of photosynthetic model parameters and leaf area index from global Fluxnet eddy covariance data

    NARCIS (Netherlands)

    Groenendijk, M.; Dolman, A.J.; Ammann, C.; Arneth, A.; Cescatti, A.; Molen, van der M.K.; Moors, E.J.

    2011-01-01

    Global vegetation models require the photosynthetic parameters, maximum carboxylation capacity (Vcm), and quantum yield (a) to parameterize their plant functional types (PFTs). The purpose of this work is to determine how much the scaling of the parameters from leaf to ecosystem level through a

  7. Optimising view angles for the estimation of leaf area index via ...

    Indian Academy of Sciences (India)

    fixed to its measured value for corn leaf in Huailai. RS Experiment Station, and is expressed by the ellipsoidal distribution function (Campbell 1985). 3.2 Information content distribution. To examine the distribution of information content with respect to view angle, the entropy differences of canopy reflectance data for NIR ...

  8. Continual observation on crop leaf area index using wireless sensors network

    International Nuclear Information System (INIS)

    Jiao, Sihong

    2014-01-01

    Crop structural parameter, i.e. leaf area index(LAI), is the main factor that can effect the solar energy re-assignment in the canopy. An automatic measuring system which is designed on the basis of wireless sensors network(WSN) is present in this paper. The system is comprised of two types of node. One is the measurement nodes which measured solar irradiance and were deployed beneath and above the canopy respectively, and another is a sink node which was used to collect data from the other measurement nodes. The measurement nodes also have ability to repeater data from one node to another and finally transfer signal to the sink node. Then the collected data of sink node are transferred to the data center through GPRS network. Using the field data collected by WSN, canopy structural parameters can be calculated using the direct transmittance which is the ratio of sun radiation captured by the measurement node beneath and above the canopy on different sun altitude angles. The proposed WSN measurement systems which is consisted of about 45 measurement node was deployed in the Heihe watershed to continually observe the crop canopy structural parameters from 25 June to 24 August 2012. To validate the performance of the WSN measured crop structural parameters, the LAI values were also measured by LAI2000. The field preliminary validation results show that the designed system can capture the varies of solar direct canopy transmittance on different time in a day, which is the basis to calculate the target canopy structural parameters. The validation results reveal that the measured LAI values derived from our propose measurement system have acceptable correlation coefficient(R2 from 0.27 to 0.96 and averaged value 0.42) with those derived from LAI2000. So it is a promising way in the agriculture application to utilize the proposed system and thus will be an efficient way to measure the crop structural parameters in the large spatial region and on the long time series

  9. Continual observation on crop leaf area index using wireless sensors network

    Science.gov (United States)

    Jiao, Sihong

    2014-03-01

    Crop structural parameter, i.e. leaf area index(LAI), is the main factor that can effect the solar energy re-assignment in the canopy. An automatic measuring system which is designed on the basis of wireless sensors network(WSN) is present in this paper. The system is comprised of two types of node. One is the measurement nodes which measured solar irradiance and were deployed beneath and above the canopy respectively, and another is a sink node which was used to collect data from the other measurement nodes. The measurement nodes also have ability to repeater data from one node to another and finally transfer signal to the sink node. Then the collected data of sink node are transferred to the data center through GPRS network. Using the field data collected by WSN, canopy structural parameters can be calculated using the direct transmittance which is the ratio of sun radiation captured by the measurement node beneath and above the canopy on different sun altitude angles. The proposed WSN measurement systems which is consisted of about 45 measurement node was deployed in the Heihe watershed to continually observe the crop canopy structural parameters from 25 June to 24 August 2012. To validate the performance of the WSN measured crop structural parameters, the LAI values were also measured by LAI2000. The field preliminary validation results show that the designed system can capture the varies of solar direct canopy transmittance on different time in a day, which is the basis to calculate the target canopy structural parameters. The validation results reveal that the measured LAI values derived from our propose measurement system have acceptable correlation coefficient(R2 from 0.27 to 0.96 and averaged value 0.42) with those derived from LAI2000. So it is a promising way in the agriculture application to utilize the proposed system and thus will be an efficient way to measure the crop structural parameters in the large spatial region and on the long time series.

  10. Teratosphaeria nubilosa, a serious leaf disease pathogen of Eucalyptus spp. in native and introduced areas.

    Science.gov (United States)

    Hunter, Gavin C; Crous, Pedro W; Carnegie, Angus J; Wingfield, Michael J

    2009-01-01

    Teratosphaeria nubilosa is a serious leaf pathogen of several Eucalyptus spp. This review considers the taxonomic history, epidemiology, host associations and molecular biology of T. nubilosa. Kingdom Fungi; Phylum Ascomycota; Class Dothideomycetes; Order Capnodiales; Family Teratosphaeriaceae; genus Teratosphaeria; species nubilosa. Pseudothecia hypophyllous, less so amphigenous, ascomata black, globose becoming erumpent, asci aparaphysate, fasciculate, bitunicate, obovoid to ellipsoid, straight or incurved, eight-spored, ascospores hyaline, non-guttulate, thin walled, straight to slightly curved, obovoid with obtuse ends, medially one-septate, slightly constricted at the median septum, tapering to both ends, ascospore germination type F, germinating from both ends, germ tubes growing parallel to the long axis of the spore with distortion of the primary ascospore cell. Teratosphaeria nubilosa is a primary pathogen of several Eucalyptus spp., including E. botryoides, E. bicostata, E. bridgesiana, E. cypellocarpa, E. dunnii, E. globulus ssp. bicostata, E. globulus ssp. globulus, E. globulus ssp. maidenii, E. globulus ssp. pseudoglobulus, E. grandis, E. gunnii, E. nitens, E. pilularis, E. quadrangulata, E. viminalis, E. grandis x E. resinifera and E. urophylla x E. globulus. Leaf spots predominantly occur on juvenile Eucalyptus foliage; however, T. nubilosa has also recently been found on mature Eucalyptus foliage. Leaf spots are amphigenous, varying in size from small spots that are round to irregular. Lesions enlarge and coalesce to form larger blotches over the leaf surface. Initial lesions appear as pale-green spots surrounded by purple margins and, once mature, are generally yellow to pale brown with dark-brown raised borders. Mycobank, http://www.mycobank.org; Mycosphaerella identification website, http://www.cbs.knaw.nl/mycosphaerella/BioloMICS.aspx.

  11. Field-scale moisture estimates using COSMOS sensors: A validation study with temporary networks and Leaf-Area-Indices

    Science.gov (United States)

    Coopersmith, Evan J.; Cosh, Michael H.; Daughtry, Craig S. T.

    2014-11-01

    The COsmic-ray Soil Moisture Observing System (COSMOS) is a new and innovative method for estimating surface and near-surface soil moisture at large (∼700 m) scales. This system accounts for liquid water within its measurement volume. Many of the sites used in the early validation of the system had low and stable vegetation water content. It is necessary to perform validation of COSMOS in a landscape with a significant change in vegetation water content to estimate its impact on the COSMOS estimate, and potentially, correct the estimate to account for the dynamic vegetation cover. A COSMOS station was installed in Beltsville, MD in the spring of 2012, within the domain of a long-term experimental station on USDA property. This station has a large array of soil moisture sensors in profile across the field, which is approximately 700 m in diameter. Frequent estimates of Leaf Area Index (LAI) were made throughout the 2012 and 2013 growing seasons (May through September). COSMOS readings, with a simple linear adjustment, were able to produce estimates of area-weighted averages of the existing in situ network with root-mean-squared-errors (RMSE) of soil-water content well below 0.04 m3/m3 and with additional modeling to account for Leaf Area Index (LAI) values, RMSE values less than 0.03 m3/m3 were achieved.

  12. Leaf Area Index (LAI) in different type of agroforestry systems based on hemispherical photographs in Cidanau Watershed

    Science.gov (United States)

    Nur Khairiah, Rahmi; Setiawan, Yudi; Budi Prasetyo, Lilik; Ayu Permatasari, Prita

    2017-01-01

    Ecological functions of agroforestry systems have perceived benefit to people around Cidanau Watershed, especially in the protection of water quality. The main causes of the problems encountered in the Cidanau Watershed are associated with the human factors, especially encroachment and conversion of forest into farmland. The encroachment has made most forest in Cidanau Watershed become bare land. To preserve the ecological function of agroforestry systems in Cidanau Watershed, monitoring of the condition of the vegetation canopy in agroforestry systems is really needed. High intensity thinning of crown density due to deforestation can change stand leaf area index dramatically. By knowing LAI, we can assess the condition of the vegetation canopy in agroforestry systems. LAI in this research was obtained from Hemispherical Photographs analysis using the threshold method in HemiView Canopy Analysis Software. Our research results indicate that there are six types of agroforestry in Cidanau Watershed i.e. Sengon Agroforestry, Clove Agroforestry, Melinjo Agroforestry, Chocolate Agroforestry, Coffee Agroforestry, and Complex Agroforestry. Several factors potentially contribute to variations in the value of LAI in different types of agroforestry. The simple assumptions about differences ranges of LAI values on six types of agroforestry is closely related to leaf area and plant population density.

  13. Tree mortality across biomes is promoted by drought intensity, lower wood density and higher specific leaf area

    Science.gov (United States)

    Greenwood, Sarah; Ruiz-Benito, Paloma; Martinez-Vilalta, Jordi; Lloret, Francisco; Kitzberger, Thomas; Allen, Craig D.; Fensham, Rod; Laughlin, Daniel C.; Kattge, Jens; Bönisch, Gerhard; Kraft, Nathan J. B.; Jump, Alistair S.

    2017-01-01

    Drought events are increasing globally, and reports of consequent forest mortality are widespread. However, due to a lack of a quantitative global synthesis, it is still not clear whether drought-induced mortality rates differ among global biomes and whether functional traits influence the risk of drought-induced mortality. To address these uncertainties, we performed a global meta-analysis of 58 studies of drought-induced forest mortality. Mortality rates were modelled as a function of drought, temperature, biomes, phylogenetic and functional groups and functional traits. We identified a consistent global-scale response, where mortality increased with drought severity [log mortality (trees trees−1 year−1) increased 0.46 (95% CI = 0.2–0.7) with one SPEI unit drought intensity]. We found no significant differences in the magnitude of the response depending on forest biomes or between angiosperms and gymnosperms or evergreen and deciduous tree species. Functional traits explained some of the variation in drought responses between species (i.e. increased from 30 to 37% when wood density and specific leaf area were included). Tree species with denser wood and lower specific leaf area showed lower mortality responses. Our results illustrate the value of functional traits for understanding patterns of drought-induced tree mortality and suggest that mortality could become increasingly widespread in the future.

  14. An application of plot-scale NDVI in predicting carbon dioxide exchange and leaf area index in heterogeneous subarctic tundra

    International Nuclear Information System (INIS)

    Dagg, J.; Lafleur, P.

    2010-01-01

    This paper reported on a study that examined the flow of carbon into and out of tundra ecosystems. It is necessary to accurately predict carbon dioxide (CO 2 ) exchange in the Tundra because of the impacts of climate change on carbon stored in permafrost. Understanding the relationships between the normalized difference vegetation index (NDVI) and vegetation and CO 2 exchange may explain how small-scale variation in vegetation community extends to remotely sensed estimates of landscape characteristics. In this study, CO 2 fluxes were measured with a portable chamber in a range of Tundra vegetation communities. Biomass and leaf area were measured with destructive harvest, and NDVI was obtained using a hand-held infrared camera. There was a weak correlation between NDVI and leaf area index in some vegetation communities, but a significant correlation between NDVI and biomass, including mosses. NDVI was found to be strongly related to photosynthetic activity and net CO 2 uptake in all vegetation groups. However, NDVI related to ecosystem respiration only in wet sedge. It was concluded that at plot scale, the ability of NDVI to predict ecosystem properties and CO 2 exchange in heterogeneous Tundra vegetation is variable.

  15. Vegetative propagation of Plukenetia polyadenia by cuttings: effects of leaf area and indole-3-butyric acid concentration

    Directory of Open Access Journals (Sweden)

    R. Solis

    Full Text Available Abstract The seeds of Plukenetia polyadenia have high levels of unsaturated fatty acids and are used as medicine and food for native people in the Peruvian and Brazilian Amazon. The objective of this study was to develop a method for vegetative propagation of Plukenetia polyadenia by rooting of cuttings. The experiment was laid out in a randomized complete block design with 12 treatments and 3 replications of 8 cuttings, in a 3 × 4 factorial arrangement. The factors were: 3 levels of leaf area (25, 50 and 75% and 3 indole-3-butyric acid - IBA concentrations (9.84, 19.68 and 29.52mM and a control without IBA. Data were submitted to analysis of variance and means were compared by Tukey test at 5% probability. Our results show that the use of cuttings with 50% of leaf area and treatment with 29.52mM of IBA induced high percentages of rooting (93% and the best root formation. Vegetative propagation of Plukenetia polyadenia by cuttings will be used as a tool to conserve and propagate germplasm in breeding programs.

  16. Vegetative propagation of Plukenetia polyadenia by cuttings: effects of leaf area and indole-3-butyric acid concentration.

    Science.gov (United States)

    Solis, R; Pezo, M; Diaz, G; Arévalo, L; Cachique, D

    2017-01-01

    The seeds of Plukenetia polyadenia have high levels of unsaturated fatty acids and are used as medicine and food for native people in the Peruvian and Brazilian Amazon. The objective of this study was to develop a method for vegetative propagation of Plukenetia polyadenia by rooting of cuttings. The experiment was laid out in a randomized complete block design with 12 treatments and 3 replications of 8 cuttings, in a 3 × 4 factorial arrangement. The factors were: 3 levels of leaf area (25, 50 and 75%) and 3 indole-3-butyric acid - IBA concentrations (9.84, 19.68 and 29.52mM) and a control without IBA. Data were submitted to analysis of variance and means were compared by Tukey test at 5% probability. Our results show that the use of cuttings with 50% of leaf area and treatment with 29.52mM of IBA induced high percentages of rooting (93%) and the best root formation. Vegetative propagation of Plukenetia polyadenia by cuttings will be used as a tool to conserve and propagate germplasm in breeding programs.

  17. Tree mortality across biomes is promoted by drought intensity, lower wood density and higher specific leaf area.

    Science.gov (United States)

    Greenwood, Sarah; Ruiz-Benito, Paloma; Martínez-Vilalta, Jordi; Lloret, Francisco; Kitzberger, Thomas; Allen, Craig D; Fensham, Rod; Laughlin, Daniel C; Kattge, Jens; Bönisch, Gerhard; Kraft, Nathan J B; Jump, Alistair S

    2017-04-01

    Drought events are increasing globally, and reports of consequent forest mortality are widespread. However, due to a lack of a quantitative global synthesis, it is still not clear whether drought-induced mortality rates differ among global biomes and whether functional traits influence the risk of drought-induced mortality. To address these uncertainties, we performed a global meta-analysis of 58 studies of drought-induced forest mortality. Mortality rates were modelled as a function of drought, temperature, biomes, phylogenetic and functional groups and functional traits. We identified a consistent global-scale response, where mortality increased with drought severity [log mortality (trees trees -1  year -1 ) increased 0.46 (95% CI = 0.2-0.7) with one SPEI unit drought intensity]. We found no significant differences in the magnitude of the response depending on forest biomes or between angiosperms and gymnosperms or evergreen and deciduous tree species. Functional traits explained some of the variation in drought responses between species (i.e. increased from 30 to 37% when wood density and specific leaf area were included). Tree species with denser wood and lower specific leaf area showed lower mortality responses. Our results illustrate the value of functional traits for understanding patterns of drought-induced tree mortality and suggest that mortality could become increasingly widespread in the future. © 2017 John Wiley & Sons Ltd/CNRS.

  18. A phenomics approach to the analysis of the influence of glutathione on leaf area and abiotic stress tolerance in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Daniel eSchnaubelt

    2013-11-01

    Full Text Available Reduced glutathione (GSH is an abundant low molecular weight plant thiol. It fulfils multiple functions in plant biology, many of which remain poorly characterised. A phenomics approach was therefore used to investigate the effects of glutathione homeostasis on growth and stress tolerance in Arabidopsis thaliana. Rosette leaf area was compared in mutants that are either defective in GSH synthesis (cad2, pad2 and rax1 or the export of γ-glutamyl cysteine and GSH from the chloroplast (clt and in wild type plants under standard growth conditions and following exposure to a range of abiotic stress treatments, including oxidative stress, water stress and high salt. In the absence of stress, the GSH synthesis mutants had a significantly lower leaf area than the wild type. Conversely, the clt mutant has a greater leaf area and a significantly reduced lateral root density than the wild type. These findings demonstrate that cellular glutathione homeostasis exerts an influence on root architecture and on rosette area. An impaired capacity to synthesise GSH or a specific depletion of the cytosolic GSH pool did not adversely affect leaf area in plants exposed to short term abiotic stress. However, the negative effects of long term exposure to oxidative stress and high salt on leaf area were less marked in the GSH synthesis mutants than the wild type. These findings demonstrate the importance of cellular glutathione homeostasis in the regulation of plant growth under optimal and stress conditions.

  19. A phenomics approach to the analysis of the influence of glutathione on leaf area and abiotic stress tolerance in Arabidopsis thaliana.

    Science.gov (United States)

    Schnaubelt, Daniel; Schulz, Philipp; Hannah, Matthew A; Yocgo, Rosita E; Foyer, Christine H

    2013-01-01

    Reduced glutathione (GSH) is an abundant low molecular weight plant thiol. It fulfills multiple functions in plant biology, many of which remain poorly characterized. A phenomics approach was therefore used to investigate the effects of glutathione homeostasis on growth and stress tolerance in Arabidopsis thaliana. Rosette leaf area was compared in mutants that are either defective in GSH synthesis (cad2, pad2, and rax1) or the export of γ-glutamylcysteine and GSH from the chloroplast (clt) and in wild-type plants under standard growth conditions and following exposure to a range of abiotic stress treatments, including oxidative stress, water stress, and high salt. In the absence of stress, the GSH synthesis mutants had a significantly lower leaf area than the wild type. Conversely, the clt mutant has a greater leaf area and a significantly reduced lateral root density than the wild type. These findings demonstrate that cellular glutathione homeostasis exerts an influence on root architecture and on rosette area. An impaired capacity to synthesize GSH or a specific depletion of the cytosolic GSH pool did not adversely affect leaf area in plants exposed to short-term abiotic stress. However, the negative effects of long-term exposure to oxidative stress and high salt on leaf area were less marked in the GSH synthesis mutants than the wild type. These findings demonstrate the importance of cellular glutathione homeostasis in the regulation of plant growth under optimal and stress conditions.

  20. Pre- and post-windstorm leaf area index of Carpinus betulus trees in an urban forest patch

    Directory of Open Access Journals (Sweden)

    Melih Öztürk

    2016-07-01

    Full Text Available Natural disturbances are rather rare for the urban forests compared to the anthropogenic ones. However, forcible natural impact may be substantially destructive such as severe storms. Instantaneous defoliation is one of the significant signatures of the storm severity. A multipurpose vegetation parameter, Leaf Area Index (LAI is used as an indicator of instantaneous defoliation which may occur as a result of immediate leaf fall jointly with the stem and branch breakages or uprooting. Enhancing the idea, LAI of the Carpinus betulus trees were analyzed before and after the devastating storm in Balamba urban forest patch at the northwestern of Turkey. The maximum speed of the severe storm was 117 km/h and enough to destruct the trees. Consequently LAI ceased 24% as a result of instantaneous defoliation both in recreation and control sites indicating the severity of damage. Southwester which is associated with heavy rainfall and represent the winds with maximum speeds in the region led to this change. The inexistence of extraordinary meteorological data before and after the severe storm indicates that the wind speed was the main reason for such damage. The same percentage of LAI decrease within the recreation and control sites supports the situation that the soil compaction due to recreation has no definite influence on the severity of windthrow. Scattered pattern of annual maximum wind speeds particularly for the last fifteen years are possible to be the implications for climate change.

  1. 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.

  2. 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.

  3. 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

  4. The forced sound transmission of finite single leaf walls using a variational technique.

    Science.gov (United States)

    Brunskog, Jonas

    2012-09-01

    The single wall is the simplest element of concern in building acoustics, but there still remain some open questions regarding the sound insulation of this simple case. The two main reasons for this are the effects on the excitation and sound radiation of the wall when it has a finite size, and the fact that the wave field in the wall is consisting of two types of waves, namely forced waves due to the exciting acoustic field, and free bending waves due to reflections in the boundary. The aim of the present paper is to derive simple analytical formulas for the forced part of the airborne sound insulation of a single homogeneous wall of finite size, using a variational technique based on the integral-differential equation of the fluid loaded wall. The so derived formulas are valid in the entire audible frequency range. The results are compared with full numerical calculations, measurements and alternative theory, with reasonable agreement.

  5. The forced sound transmission of finite single leaf walls using a variational technique

    DEFF Research Database (Denmark)

    Brunskog, Jonas

    2012-01-01

    The single wall is the simplest element of concern in building acoustics, but there still remain some open questions regarding the sound insulation of this simple case. The two main reasons for this are the effects on the excitation and sound radiation of the wall when it has a finite size......, and the fact that the wave field in the wall is consisting of two types of waves, namely forced waves due to the exciting acoustic field, and free bending waves due to reflections in the boundary. The aim of the present paper is to derive simple analytical formulas for the forced part of the airborne sound...... insulation of a single homogeneous wall of finite size, using a variational technique based on the integral-differential equation of the fluid loaded wall. The so derived formulas are valid in the entire audible frequency range. The results are compared with full numerical calculations, measurements...

  6. Global meta-analysis of leaf area index in wetlands indicates uncertainties in understanding of their ecosystem function

    Science.gov (United States)

    Dronova, I.; Taddeo, S.; Foster, K.

    2017-12-01

    Projecting ecosystem responses to global change relies on the accurate understanding of properties governing their functions in different environments. An important variable in models of ecosystem function is canopy leaf area index (LAI; leaf area per unit ground area) declared as one of the Essential Climate Variables in the Global Climate Observing System and extensively measured in terrestrial landscapes. However, wetlands have been largely under-represented in these efforts, which globally limits understanding of their contribution to carbon sequestration, climate regulation and resilience to natural and anthropogenic disturbances. This study provides a global synthesis of >350 wetland-specific LAI observations from 182 studies and compares LAI among wetland ecosystem and vegetation types, biomes and measurement approaches. Results indicate that most wetland types and even individual locations show a substantial local dispersion of LAI values (average coefficient of variation 65%) due to heterogeneity of environmental properties and vegetation composition. Such variation indicates that mean LAI values may not sufficiently represent complex wetland environments, and the use of this index in ecosystem function models needs to incorporate within-site variation in canopy properties. Mean LAI did not significantly differ between direct and indirect measurement methods on a pooled global sample; however, within some of the specific biomes and wetland types significant contrasts between these approaches were detected. These contrasts highlight unique aspects of wetland vegetation physiology and canopy structure affecting measurement principles that need to be considered in generalizing canopy properties in ecosystem models. Finally, efforts to assess wetland LAI using remote sensing strongly indicate the promise of this technology for cost-effective regional-scale modeling of canopy properties similar to terrestrial systems. However, such efforts urgently require more

  7. Application of 3D triangulations of airborne laser scanning data to estimate boreal forest leaf area index

    Science.gov (United States)

    Majasalmi, Titta; Korhonen, Lauri; Korpela, Ilkka; Vauhkonen, Jari

    2017-07-01

    We propose 3D triangulations of airborne Laser Scanning (ALS) point clouds as a new approach to derive 3D canopy structures and to estimate forest canopy effective LAI (LAIe). Computational geometry and topological connectivity were employed to filter the triangulations to yield a quasi-optimal relationship with the field measured LAIe. The optimal filtering parameters were predicted based on ALS height metrics, emulating the production of maps of LAIe and canopy volume for large areas. The LAIe from triangulations was validated with field measured LAIe and compared with a reference LAIe calculated from ALS data using logarithmic model based on Beer's law. Canopy transmittance was estimated using All Echo Cover Index (ACI), and the mean projection of unit foliage area (β) was obtained using no-intercept regression with field measured LAIe. We investigated the influence species and season on the triangulated LAIe and demonstrated the relationship between triangulated LAIe and canopy volume. Our data is from 115 forest plots located at the southern boreal forest area in Finland and for each plot three different ALS datasets were available to apply the triangulations. The triangulation approach was found applicable for both leaf-on and leaf-off datasets after initial calibration. Results showed the Root Mean Square Errors (RMSEs) between LAIe from triangulations and field measured values agreed the most using the highest pulse density data (RMSE = 0.63, the coefficient of determination (R2) = 0.53). Yet, the LAIe calculated using ACI-index agreed better with the field measured LAIe (RMSE = 0.53 and R2 = 0.70). The best models to predict the optimal alpha value contained the ACI-index, which indicates that within-crown transmittance is accounted by the triangulation approach. The cover indices may be recommended for retrieving LAIe only, but for applications which require more sophisticated information on canopy shape and volume, such as radiative transfer models, the

  8. Estimating leaf area and above-ground biomass of forest regeneration areas using a corrected normalized difference vegetation index

    Science.gov (United States)

    Tommy L. Coleman; James H. Miller; Bruce R. Zutter

    1992-01-01

    The objective of this study was to investigate the regression relations between vegetation indices derived from remotely-sensed data of single and mixed forest regeneration plots. Loblolly pine (Pinus taeda L.) seedlings, sweelgum (Liquidambar styraciflua L.) seedlings and broomsedge (Andropogon virginicus L.)...

  9. Remote sensing based mapping of leaf nitrogen and leaf area index in European landscapes using the REGularized canopy reFLECtance (REGFLEC) model

    DEFF Research Database (Denmark)

    Boegh, E.; Houborg, R.; Bienkowski, J.

    2011-01-01

    index (LAI) are important determinants of the maximum CO2 Methods/Approach uptake by plants and trees. In the EU project NitroEurope, high spatial resolution (10-20 m) remote sensing data from the HRG and HRVIR sensors onboard the SPOT satellites were acquired to derive maps of leaf N and LAI for 5...

  10. Acclimation of photosynthetic capacity to irradiance in tree canopies in relation to leaf nitrogen concentration and leaf mass per unit area

    NARCIS (Netherlands)

    Meir, P.; Kruijt, B.; Broadmeadow, M.; Barbosa, E.; Kull, O.; Carswell, F.; Nobre, A.; Jarvis, P.G.

    2002-01-01

    The observation of acclimation in leaf photosynthetic capacity to differences in growth irradiance has been widely used as support for a hypothesis that enables a simplification of some soil-vegetation-atmosphere transfer (SVAT) photosynthesis models. The acclimation hypothesis requires that

  11. Relationship between aerodynamic roughness length and bulk sedge leaf area index in a mixed-species boreal mire complex

    Science.gov (United States)

    Alekseychik, P. K.; Korrensalo, A.; Mammarella, I.; Vesala, T.; Tuittila, E.-S.

    2017-06-01

    Leaf area index (LAI) is an important parameter in natural ecosystems, representing the seasonal development of vegetation and photosynthetic potential. However, direct measurement techniques require labor-intensive field campaigns that are usually limited in time, while remote sensing approaches often do not yield reliable estimates. Here we propose that the bulk LAI of sedges (LAIs) can be estimated alternatively from a micrometeorological parameter, the aerodynamic roughness length for momentum (z0). z0 can be readily calculated from high-response turbulence and other meteorological data, typically measured continuously and routinely available at ecosystem research sites. The regressions of LAI versus z0 were obtained using the data from two Finnish natural sites representative of boreal fen and bog ecosystems. LAIs was found to be well correlated with z0 and sedge canopy height. Superior method performance was demonstrated in the fen ecosystem where the sedges make a bigger contribution to overall surface roughness than in bogs.

  12. Estimates of leaf area index from spectral reflectance of wheat under different cultural practices and solar angle

    Science.gov (United States)

    Asrar, G.; Kanemasu, E. T.; Yoshida, M.

    1985-01-01

    The influence of management practices and solar illumination angle on the leaf area index (LAI) was estimated from measurements of wheat canopy reflectance evaluated by two methods, a regression formula and an indirect technique. The date of planting and the time of irrigation in relation to the stage of plant growth were found to have significant effects on the development of leaves in spring wheat. A reduction in soil moisture adversely affected both the duration and magnitude of the maximum LAI for late planting dates. In general, water stress during vegetative stages resulted in a reduction in maximum LAI, while water stress during the reproductive period shortened the duration of green LAI in spring wheat. Canopy geometry and solar angle also affected the spectral properties of the canopies, and hence the estimated LAI. Increase in solar zenith angles resulted in a general increase in estimated LAI obtained from both methods.

  13. Clonal Propagation of Khaya senegalensis: The Effects of Stem Length, Leaf Area, Auxins, Smoke Solution, and Stockplant Age

    Directory of Open Access Journals (Sweden)

    Catherine Ky-Dembele

    2011-01-01

    Full Text Available Khaya senegalensis is a multipurpose African timber species. The development of clonal propagation could improve plantation establishment, which is currently impeded by mahogany shoot borer. To examine its potential for clonal propagation, the effects of cutting length, leaf area, stockplant maturation, auxin, and smoke solution treatments were investigated. Leafy cuttings rooted well (up to 80% compared to leafless cuttings (0%. Cuttings taken from seedlings rooted well (at least 95%, but cuttings obtained from older trees rooted poorly (5% maximum. The rooting ability of cuttings collected from older trees was improved (16% maximum by pollarding. Auxin application enhanced root length and the number of roots while smoke solution did not improve cuttings' rooting ability. These results indicate that juvenile K. senegalensis is amenable to clonal propagation, but further work is required to improve the rooting of cuttings from mature trees.

  14. Leaf Area Index, Biomass Carbon and Growth Rate of Radiata Pine Genetic Types and Relationships with LiDAR

    Directory of Open Access Journals (Sweden)

    Robert J. McGaughey

    2011-08-01

    Full Text Available Relationships between discrete-return light detection and ranging (LiDAR data and radiata pine leaf area index (LAI, stem volume, above ground carbon, and carbon sequestration were developed using 10 plots with directly measured biomass and leaf area data, and 36 plots with modelled carbon data. The plots included a range of genetic types established on north- and south-facing aspects. Modelled carbon was highly correlated with directly measured crown, stem, and above ground biomass data, with r = 0.92, 0.97 and 0.98, respectively. LiDAR canopy percentile height (P30 and cover, based on all returns above 0.5 m, explained 81, 88, and 93% of the variation in directly measured crown, stem, and above ground live carbon and 75, 89 and 88% of the modelled carbon, respectively. LAI (all surfaces ranged between 8.8–19.1 in the 10 plots measured at age 9 years. The difference in canopy percentile heights (P95–P30 and cover based on first returns explained 80% of the variation in total LAI. Periodic mean annual increments in stem volume, above ground live carbon, and total carbon between ages 9 and 13 years were significantly related to (P95–P30, with regression models explaining 56, 58, and 55%, respectively, of the variation in growth rate per plot. When plot aspect and genetic type were included with (P95–P30, the R2 of the regression models for stem volume, above ground live carbon, and total carbon increment increased to 90, 88, and 88%, respectively, which indicates that LiDAR regression equations for estimating stock changes can be substantially improved by incorporating supplementary site and crop data.

  15. Indirect estimations and spatial variation in leaf area index of coniferous, deciduous and mixed forest stands in Forsmark and Laxemar

    International Nuclear Information System (INIS)

    Tagesson, Torbern

    2006-12-01

    Two sites in Sweden are investigated for a potential deep repository of the nuclear waste, the Laxemar investigation area (57 deg 5 min N, 16 deg 7 min E) and the Forsmark investigation area (60 deg 4 min N, 18 deg 2 min E). In the characterisation of these sites, development of site descriptive models is an important part. Leaves are the main surface were an exchange of matter and energy between the atmosphere and the biosphere takes place, and leaf area index (LAI) of the vegetation cover is an important variable correlated to a number of ecophysiological parameters and hereby an important parameter in ecosystem models. In the investigation areas, LAI of boreal and temperate ecosystems were therefore estimated indirectly through optical measurements using the LAI-2000 (LI-COR, Cambridge UK) and TRAC (Tracing Radiation and Architecture of Canopies). On average, measured maximum LAI was 3.40 in Laxemar and 3.43 in Forsmark; minimum LAI was 1.65 in Laxemar and 1.97 in Forsmark. Forest inventory data showed that LAI is positively correlated with basal area, stand height, stand volume and breast height tree diameter. For the coniferous stands, there was also a linearly negative relationship with age. In the Laxemar investigation area, there were no significant relationships for LAI with a satellite derived kNN (kNearest Neighbor) data set with stand height, stand volume and stand age. The kNN data set can therefore not be used to extrapolate measured LAI over the Laxemar investigation area. There were significant relationships between LAI and the normalized difference vegetation index (NDVI) for coniferous, deciduous and mixed forest stands in the Laxemar investigation area. A NDVI image could be used to extrapolate LAI over the entire investigation area. For the Forsmark investigation area, effective LAI for all stands were correlated to NDVI and this relationship could then be used for extrapolation. The effective LAI image was afterwards corrected for average

  16. Indirect estimations and spatial variation in leaf area index of coniferous, deciduous and mixed forest stands in Forsmark and Laxemar

    Energy Technology Data Exchange (ETDEWEB)

    Tagesson, Torbern [Dept. of Physical Geography and Ecosystem Analysis, Lund Univ., Lund (Sweden)

    2006-12-15

    Two sites in Sweden are investigated for a potential deep repository of the nuclear waste, the Laxemar investigation area (57 deg 5 min N, 16 deg 7 min E) and the Forsmark investigation area (60 deg 4 min N, 18 deg 2 min E). In the characterisation of these sites, development of site descriptive models is an important part. Leaves are the main surface were an exchange of matter and energy between the atmosphere and the biosphere takes place, and leaf area index (LAI) of the vegetation cover is an important variable correlated to a number of ecophysiological parameters and hereby an important parameter in ecosystem models. In the investigation areas, LAI of boreal and temperate ecosystems were therefore estimated indirectly through optical measurements using the LAI-2000 (LI-COR, Cambridge UK) and TRAC (Tracing Radiation and Architecture of Canopies). On average, measured maximum LAI was 3.40 in Laxemar and 3.43 in Forsmark; minimum LAI was 1.65 in Laxemar and 1.97 in Forsmark. Forest inventory data showed that LAI is positively correlated with basal area, stand height, stand volume and breast height tree diameter. For the coniferous stands, there was also a linearly negative relationship with age. In the Laxemar investigation area, there were no significant relationships for LAI with a satellite derived kNN (kNearest Neighbor) data set with stand height, stand volume and stand age. The kNN data set can therefore not be used to extrapolate measured LAI over the Laxemar investigation area. There were significant relationships between LAI and the normalized difference vegetation index (NDVI) for coniferous, deciduous and mixed forest stands in the Laxemar investigation area. A NDVI image could be used to extrapolate LAI over the entire investigation area. For the Forsmark investigation area, effective LAI for all stands were correlated to NDVI and this relationship could then be used for extrapolation. The effective LAI image was afterwards corrected for average

  17. Effects of thinning on wood production, leaf area index, transpiration and canopy interception of a plantation subject to drought.

    Science.gov (United States)

    McJannet, D; Vertessy, R

    2001-08-01

    We conducted thinning trials in a 5-year-old Eucalyptus globulus ssp. globulus Labill plantation near Warrenbayne, northeastern Victoria, Australia, where soil salinization and waterlogging are common, and assessed treatment effects on tree growth, water use and survival. Half-hectare plots were thinned from the original density of 1100 stems ha(-1) to densities of 800, 600 and 400 stems ha(-1), and stem diameter increment, leaf area index, transpiration, canopy interception and depth of tree water source monitored for 21 months. Two drought periods occurred during the study, rainfall was 30% below the long-term average and there was severe mortality in all three plots. Analysis of deuterium abundance in soil and xylem water indicated that the trees accessed water only from the top meter of the soil profile. Transpiration rates were higher in the most heavily thinned plot than in the least thinned plot, which underwent a reduction in basal area during the study. The most heavily thinned plot increased in basal area by 10% during the study. Edge trees had significantly greater diameters than trees from the middle of the plots.

  18. A PROPOSED METHODOLOGY FOR THE CORRECTION OF THE LEAF AREA INDEX MEASURED WITH A CEPTOMETER FOR PINUS AND EUCALYPTUS FORESTS

    Directory of Open Access Journals (Sweden)

    Domingos Mendes Lopes

    Full Text Available ABSTRACT Leaf area index (LAI is an important parameter controlling many biological and physiological processes associated with vegetation on the Earth's surface, such as photosynthesis, respiration, transpiration, carbon and nutrient cycle and rainfall interception. LAI can be measured indirectly by sunfleck ceptometers in an easy and non-destructive way but this practical methodology tends to underestimated when measured by these instruments. Trying to correct this underestimation, some previous studies heave proposed the multiplication of the observed LAI value by a constant correction factor. The assumption of this work is LAI obtained from the allometric equations are not so problematic and can be used as a reference LAI to develop a new methodology to correct the ceptometer one. This new methodology indicates that the bias (the difference between the ceptometer and the reference LAI is estimated as a function of the basal area per unit ground area and that bias is summed to the measured value. This study has proved that while the measured Pinus LAI needs a correction, there is no need for that correction for the Eucalyptus LAI. However, even for this last specie the proposed methodology gives closer estimations to the real LAI values.

  19. Changes in nutrients and decay rate of Ginkgo biloba leaf litter exposed to elevated O3 concentration in urban area

    Directory of Open Access Journals (Sweden)

    Wei Fu

    2018-03-01

    Full Text Available Ground-level ozone (O3 pollution has been widely concerned in the world, particularly in the cities of Asia, including China. Elevated O3 concentrations have potentially influenced growth and nutrient cycling of trees in urban forest. The decomposition characteristics of urban tree litters under O3 exposure are still poorly known. Ginkgo biloba is commonly planted in the cities of northern China and is one of the main tree species in the urban forest of Shenyang, where concentrations of ground-level O3 are very high in summer. Here, we hypothesized that O3 exposure at high concentrations would alter the decomposition rate of urban tree litter. In open-top chambers (OTCs, 5-year-old G. biloba saplings were planted to investigate the impact of elevated O3 concentration (120 ppb on changes in nutrient contents and decomposition rate of leaf litters. The results showed that elevated O3 concentration significantly increased K content (6.31 ± 0.29 vs 17.93 ± 0.40, P < 0.01 in leaves of G. biloba, significantly decreased the contents of total phenols (2.82 ± 0.93 vs 1.60 ± 0.44, P < 0.05 and soluble sugars (86.51 ± 19.57 vs 53.76 ± 2.40, P < 0.05, but did not significantly alter the contents of C, N, P, lignin and condensed tannins, compared with that in ambient air. Furthermore, percent mass remaining in litterbags after 150 days under ambient air and elevated O3 concentration was 56.0% and 52.8%, respectively. No significant difference between treatments was observed in mass remaining at any sampling date during decomposition. The losses of the nutrients in leaf litters of G. biloba showed significant seasonal differences regardless of O3 treatment. However, we found that elevated O3 concentration slowed down the leaf litter decomposition only at the early decomposition stage, but slightly accelerated the litter decomposition at the late stage (after 120 days. This study provides our understanding of the ecological processes regulating

  20. Estimation of leaf area index for cotton canopies using the LI-COR LAI-2000 plant canopy analyzer

    International Nuclear Information System (INIS)

    Hicks, S.K.; Lascano, R.J.

    1995-01-01

    Measurement of leaf area index (LAI) is useful for understanding cotton (Gossypium hirsutum L.) growth, water use, and canopy light interception. Destructive measurement is time consuming and labor intensive. Our objective was to evaluate sampling procedures using the Li-Cor (Lincoln, NE) LAI 2000 plant canopy analyzer (PCA) for nondestructive estimation of cotton LAI on the southern High Plains of Texas. We evaluated shading as a way to allow PCA measurements in direct sunlight and the influence of solar direction when using this procedure. We also evaluated a test of canopy homogeneity (information required for setting PCA field of view), determined the number of below-canopy measurements required, examined the influence of leaf wilting on PCA LAI determinations, and tested an alternative method (masking the sensor's two outer rings) for calculating LAI from PCA measurements. The best agreement between PCA and destructively measured LAI values was obtained when PCA observations were made either during uniformly overcast conditions or around solar noon using the shading method. Heterogeneous canopies with large gaps between rows required both a restricted (45 degrees) azimuthal field of view and averaging the LAI values for two transects, made with the field of view parallel and then perpendicular to the row direction. This method agreed well (r2 = 0.84) with destructively measured LAI in the range of 0.5 to 3.5 and did not deviate from a 1:1 relationship. The PCA underestimated LAI by greater than or equal 20% when measurements were made on canopies wilted due to water stress. Masking the PCA sensor's outer rings did not improve the relationship between estimated and measured LAI in the range of LAI sampled

  1. A New Equation for Deriving Vegetation Phenophase from Time Series of Leaf Area Index (LAI Data

    Directory of Open Access Journals (Sweden)

    Mingliang Che

    2014-06-01

    Full Text Available Accurately modeling the land surface phenology based on satellite data is very important to the study of vegetation ecological dynamics and the related ecosystem process. In this study, we developed a Sigmoid curve (S-curve function by integrating an asymmetric Gaussian function and a logistic function to fit the leaf area index (LAI curve. We applied the resulting asymptotic lines and the curvature extrema to derive the vegetation phenophases of germination, green-up, maturity, senescence, defoliation and dormancy. The new proposed S-curve function has been tested in a specific area (Shangdong Province, China, characterized by a specific pattern in leaf area index (LAI time course due to the dominant presence of crops. The function has not yet received any global testing. The identified phenophases were validated against measurement stations in Shandong Province. (i From the site-scale comparison, we find that the detected phenophases using the S-curve (SC algorithm are more consistent with the observations than using the logistic (LC algorithm and the asymmetric Gaussian (AG algorithm, especially for the germination and dormancy. The phenological recognition rates (PRRs of the SC algorithm are obviously higher than those of two other algorithms. The S-curve function fits the LAI curve much better than the logistic function and asymmetric Gaussian function; (ii The retrieval results of the SC algorithm are reliable and in close proximity to the green-up observed data whether using the AVHRR LAI or the improved MODIS LAI. Three inversion algorithms shows the retrieval results based on AVHRR LAI are all later than based on improved MODIS LAI. The bias statistics reveal that the retrieval results based on the AVHRR LAI datasets are more reasonable than based on the improved MODIS LAI datasets. Overall, the S-curve algorithm has the advantage of deriving vegetation phenophases across time and space as compared to the LC algorithm and the AG

  2. Mapping Urban Forest Leaf Area Index Using Lidar: A Comparison of Gap Fraction Inversion and Allometric Methods

    Science.gov (United States)

    Alonzo, M.; Bookhagen, B.; McFadden, J. P.; Sun, A.; Roberts, D. A.

    2014-12-01

    In urban areas leaf area index (LAI) is a key ecosystem structural attribute with implications for energy and water balance, gas exchange, and anthropogenic energy use. Typically, citywide LAI estimates are extrapolated from those made on forest inventory sample plots through intensive crown measurement and allometric scaling. This is a time- and labor-intensive process yielding coarse spatial resolution results. In this study we generate spatially explicit estimates of LAI using high-point density airborne lidar throughout our study area in downtown Santa Barbara, CA. We implement two theoretically distinct modeling approaches. First, based on hemispherical photography at our 71 field plots, we estimate effective LAI using scan-angle corrected lidar laser penetration metrics (LPM). For our second approach, we adapt existing allometric equations for use with a suite of crown structural metrics (e.g., tree height, crown base height) measured with lidar. This approach allows for estimates of LAI to be made at the individual tree crown scale (ITC). This is important for evaluating fine-scale interactions between canopy and urban surfaces. The LPM method resulted in good agreement with field estimates (r2 = 0.80) and a slope of near unity (β = 0.998) using a model that assumed a spherical leaf angle distribution. Within ITC segments that were automatically delineated using watershed segmentation, lidar estimates of crown structure closely paralleled field measurements (r2=0.87 for crown length). LAI estimates based on the lidar structural variables corresponded well with estimates from field measurements (r2 = 0.84). Agreement between the LPM and allometric lidar methods was also strong across the 71 validation plots (r2 = 0.88) and among 450 sample points (r2 = 0.72) randomly distributed throughout the citywide maps. This is notably higher than the agreement between the hemiphoto and allometric ground-based estimates (r2 = 0.56). The allometric approach generally

  3. Leaf-litter microfungal community on poor fen plant debris in Torfy Lake area (Central Poland)

    OpenAIRE

    Mateusz Wilk; Agnieszka Banach; Julia Pawłowska; Marta Wrzosek

    2014-01-01

    The purpose of this study was to initially evaluate the species diversity of microfungi growing on litter of 15 plant species occurring on the poor fen and neighbouring area of the Torfy Lake, Masovian voivodeship, Poland. The lake is located near the planned road investment (construction of the Warsaw southern express ring road S2). The place is biologically valuable as there are rare plant communities from Rhynchosporion albae alliance protected under the Habitats Directive adopted by the E...

  4. LEAF AREA DYNAMICS AND ABOVEGROUND BIOMASS OF SPECIFIC VEGETATION TYPES OF A SEMI-ARID GRASSLAND IN SOUTHERN ETHIOPIA

    Directory of Open Access Journals (Sweden)

    Bosco Kidake Kisambo

    2016-12-01

    Full Text Available Leaf Area Index (LAI dynamics and aboveground biomass of a semi-arid grassland region in Southern Ethiopia were determined over a long rain season. The vegetation was categorized into four distinct vegetation types namely Grassland (G, Tree-Grassland (TG, Bushed-Grassland (BG and Bush-Tree grassland (BT. LAI was measured using a Plant Canopy Analyzer (LAI2000. Biomass dynamics of litter and herbaceous components were determined through clipping while the above ground biomass of trees and shrubs were estimated using species-specific allometric equations from literature. LAI showed a seasonal increase over the season with the maximum recorded in the BG vegetation (2.52. Total aboveground biomass for the different vegetation types ranged from 0.61 ton C/ha in areas where trees were non-existent to 8.80 ± 3.81ton C/ha in the Tree-Grassland vegetation in the study site. A correlation of LAI and AGB yielded a positive relationship with an R2 value of 0.55. The results demonstrate the importance of tropical semi-arid grasslands as carbon sinks hence their potential in mitigation of climate change.

  5. A Prior Knowledge-Based Method to Derivate High-Resolution Leaf Area Index Maps with Limited Field Measurements

    Directory of Open Access Journals (Sweden)

    Yuechan Shi

    2016-12-01

    Full Text Available High-resolution leaf area index (LAI maps from remote sensing data largely depend on empirical models, which link field LAI measurements to the vegetation index. The existing empirical methods often require the field measurements to be sufficient for constructing a reliable model. However, in many regions of the world, there are limited field measurements available. This paper presents a prior knowledge-based (PKB method to derivate LAI with limited field measurements, in an effort to improve the accuracy of empirical model. Based on the assumption that the experimental sites with the same vegetation type can be represented by similar models, a priori knowledge for crops was extracted from the published models in various cropland sites. The knowledge, composed of an initial guess of each model parameter with the associated uncertainty, was then combined with the local field measurements to determine a semi-empirical model using the Bayesian inversion method. The proposed method was evaluated at a cropland site in the Huailai region of Hebei Province, China. Compared with the regression method, the proposed PKB method can effectively improve the accuracy of empirical model and LAI estimation, when the field measurements were limited. The results demonstrate that a priori knowledge extracted from the universal sites can provide important auxiliary information to improve the representativeness of the empirical model in a given study area.

  6. Leaf area development, dry weight accumulation and solar energy conversion efficiencies of Phaseolus vulgaris L. under different soil moisture levels near Nairobi, Kenya

    NARCIS (Netherlands)

    Muniafu, M.M.; Macharia, J.N.M.; Stigter, C.J.; Coulson, G.L.

    1999-01-01

    Leaf area development, dry weight accumulation and solar energy conversion efficiencies of Phaseolus vulgaris L. cv GLP-2 under two soil moisture levels in two contrasting seasons near Nairobi, Kenya were investigated. The experiment confirms that dry weights and yields of Phaseolus vulgaris are

  7. Examining variation in the leaf mass per area of dominant species across two contrasting tropical gradients in light of community assembly

    NARCIS (Netherlands)

    Neyret, Margot; Bentley, Lisa Patrick; Oliveras Menor, Imma; Marimon, Beatriz S.; Marimon-Junior, Ben Hur; Almeida de Oliveira, Edmar; Barbosa Passos, Fábio; Castro Ccoscco, Rosa; Santos, dos Josias; Matias Reis, Simone; Morandi, Paulo S.; Rayme Paucar, Gloria; Robles Cáceres, Arturo; Valdez Tejeira, Yolvi; Yllanes Choque, Yovana; Salinas, Norma; Shenkin, Alexander; Asner, Gregory P.; Díaz, Sandra; Enquist, Brian J.; Malhi, Yadvinder

    2016-01-01

    Understanding variation in key functional traits across gradients in high diversity systems and the ecology of community changes along gradients in these systems is crucial in light of conservation and climate change. We examined inter- and intraspecific variation in leaf mass per area (LMA) of

  8. 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

  9. Leaf-litter microfungal community on poor fen plant debris in Torfy Lake area (Central Poland

    Directory of Open Access Journals (Sweden)

    Mateusz Wilk

    2014-06-01

    Full Text Available The purpose of this study was to initially evaluate the species diversity of microfungi growing on litter of 15 plant species occurring on the poor fen and neighbouring area of the Torfy Lake, Masovian voivodeship, Poland. The lake is located near the planned road investment (construction of the Warsaw southern express ring road S2. The place is biologically valuable as there are rare plant communities from Rhynchosporion albae alliance protected under the Habitats Directive adopted by the European Union. On the examined plant debris 73 taxa of fungi were recorded (3 basidiomycetes, 13 ascomycetes, 2 zygomycetes, 43 anamorphic ascomycetes, 12 unidentified. Two of them, Dicranidion sp. and Wentiomyces sp. are presented here as new to Poland. Among the plant species examined, the litter of Rhododendron tomentosum harbored the highest number of fungal taxa (16. The highest percents of substrate-specific microfungi (i.e. recorded only on one plant species was noted on R. tomentosum (81.3 %, and Pteridium aquilinum (75%. It is emphasized that the lake area should be protected not only because of rare plant community but also because of the uniqueness and diversity of mycobiota.

  10. The Ratio of Leaf to Total Photosynthetic Area Influences Shade Survival and Plastic Response to Light of Green‐stemmed Leguminous Shrub Seedlings

    Science.gov (United States)

    VALLADARES, FERNANDO; HERNÁNDEZ, LIBERTAD G.; DOBARRO, IKER; GARCÍA‐PÉREZ, CRISTINA; SANZ, RUBÉN; PUGNAIRE, FRANCISCO I.

    2003-01-01

    Different plant species and organs within a plant differ in their plastic response to light. These responses influence their performance and survival in relation to the light environment, which may range from full sunlight to deep shade. Plasticity, especially with regard to physiological features, is linked to a greater capacity to exploit high light and is usually low in shade‐tolerant species. Among photosynthetic organs, green stems, which represent a large fraction of the total photosynthetic area of certain species, are hypothesized to be less capable of adjustment to light than leaves, because of biomechanical and hydraulic constraints. The response to light by leaves and stems of six species of leguminous, green‐stemmed shrubs from dry and high‐light environments was studied by growing seedlings in three light environments: deep shade, moderate shade and sun (3, 30 and 100 % of full sunlight, respectively). Survival in deep shade ranged from 2 % in Retama sphaerocarpa to 74 % in Ulex europaeus. Survival was maximal at moderate shade in all species, ranging from 80 to 98 %. The six species differed significantly in their ratio of leaf to total photosynthetic area, which influenced their light response. Survival in deep shade increased significantly with increasing ratio of leaf to total photosynthetic area, and decreased with increasing plasticity in net photosynthesis and dark respiration. Responses to light differed between stems and leaves within each species. Mean phenotypic plasticity for the variables leaf or stem specific mass, chlorophyll content, chlorophyll a/b ratio, and carotenoid to chlorophyll ratio of leaves, was inversely related to that of stems. Although mean plasticity of stems increased with the ratio of leaf to total photosynthetic area, the mean plasticity of leaves decreased. Shrubs with green stems and a low ratio of leaf to total photosynthetic area are expected to be restricted to well‐lit habitats, at least during the

  11. Single-leaf partial meniscectomy in extensive horizontal tears of the discoid lateral meniscus: Does decreased peripheral meniscal thickness affect outcomes? (Mean four-year follow-up).

    Science.gov (United States)

    Lee, Se-Won; Chun, Yong-Min; Choi, Chong-Hyuk; Kim, Sung-Jae; Jung, Min; Han, Joon-Woo; Kim, Sung-Hwan

    2016-06-01

    To evaluate whether single-leaf partial meniscectomy in horizontal tears along the entire discoid lateral meniscus has any advantages in clinical and radiological results compared with other meniscectomies in discoid lateral meniscus. A total of 145 patients with a horizontal tear pattern in symptomatic lateral discoid meniscus were retrospectively reviewed. Twenty-seven patients had undergone full-extent single-leaf partial meniscectomy (group A), 60 had undergone conventional partial meniscectomy (saucerization) maintaining peripheral meniscal height (group B), and 58 patients had undergone total meniscectomy (group C). Each patient was evaluated with the Lysholm knee score, International Knee Documentation Committee (IKDC) subjective grading, and modified Kellgren-Lawrence grade in plain radiography at their last follow-up. Group C had inferior functional results to groups A and B on the Lysholm knee score and IKDC subjective score. There was no significant difference between groups A and B. Group C fared significantly worse than groups A and B (p=0.003, pmeniscus tears, the full-extent single-leaf partial meniscectomy group had no adverse results compared with the total meniscectomy group and was not significantly different compared to the conventional partial meniscectomy group. Cohort study. Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Elevated CO2 alters distribution of nodal leaf area and enhances nitrogen uptake contributing to yield increase of soybean cultivars grown in Mollisols

    Science.gov (United States)

    Jin, Jian; Li, Yansheng; Liu, Xiaobing; Wang, Guanghua; Tang, Caixian; Yu, Zhenhua; Wang, Xiaojuan; Herbert, Stephen J.

    2017-01-01

    Understanding how elevated CO2 affects dynamics of nodal leaf growth and N assimilation is crucial for the construction of high-yielding canopy via breeding and N management to cope with the future climate change. Two soybean cultivars were grown in two Mollisols differing in soil organic carbon (SOC), and exposed to ambient CO2 (380 ppm) or elevated CO2 (580 ppm) throughout the growth stages. Elevated CO2 induced 4–5 more nodes, and nearly doubled the number of branches. Leaf area duration at the upper nodes from R5 to R6 was 4.3-fold greater and that on branches 2.4-fold higher under elevated CO2 than ambient CO2, irrespective of cultivar and soil type. As a result, elevated CO2 markedly increased the number of pods and seeds at these corresponding positions. The yield response to elevated CO2 varied between the cultivars but not soils. The cultivar-specific response was likely attributed to N content per unit leaf area, the capacity of C sink in seeds and N assimilation. Elevated CO2 did not change protein concentration in seeds of either cultivar. These results indicate that elevated CO2 increases leaf area towards the upper nodes and branches which in turn contributes yield increase. PMID:28459840

  13. STUDY ON THE ABUNDANCE OF HETEROTROF BACTERIA ON LEAF LITTER MANGROVE IN COAST AREA SEDATI-SIDOARJO OF EAST JAVA

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    Nurmalitaa D.

    2018-02-01

    Full Text Available Heterotrophic bacteria are responsible for degrading and recycling important elements such as carbon, nitrogen and phosphorus. Decomposers bacteria in mangroves litter, its existence has not been so much studied. Paper presents the results of study of the amount or abundance of rotting bacteria in the Avicennia marina, Sonneratia sp. and Rizopora apiculata on the coast of Sedati-Sidoarjo of East Java. Research method is experimental with field scale using Randomized Block Design or Randomized Complete Block Design by dividing the research for three blocks area, and statistics analysis with ANOVA. These results show that nearly 70% of mangroves in this area have been exposed or damaged. This is caused by human activities such as logging, opening of ponds and exposure of waves. The result of measurement of water quality parameter in this research ranged for pH 5.5-7.3, salinity 28-35, brightness 25-50 cm. Soil quality parameters are nitrite 0.143 mg/L, phosphate 0.160 mg/L, ammonia 2.05 mg/L, COD 80 mg/L and BOD 34 mg/L. Litter weight are 230.97 g/m2/year or 2.3 ton/ha/year in which leaf litter is the largest component of other organic waste. Waste production in this area is low compared to the result of Nurhasanah (1998 which reported 2.75 ton/ha/year. Statistics analysis with ANOVA showed significant difference between mangroves (p=0,000.

  14. Topographic Correction of ZY-3 Satellite Images and Its Effects on Estimation of Shrub Leaf Biomass in Mountainous Areas

    Directory of Open Access Journals (Sweden)

    Ming-Liang Gao

    2014-03-01

    Full Text Available The availability of ZY-3 satellite data provides additional potential for surveying, mapping, and quantitative studies. Topographic correction, which eliminates the terrain effect caused by the topographic relief, is one of the fundamental steps in data preprocessing for quantitative analysis of vegetation. In this paper, we rectified ZY-3 satellite data using five commonly used topographic correction models and investigate their impact on the regression estimation of shrub forest leaf biomass obtained from sample plots in the study area. All the corrections were assessed by means of: (1 visual inspection (2 reduction of the standard deviation (SD at different terrain slopes (3 correlation analysis of different correction results. Best results were obtained from the Minnaert+SCS correction, based on the non-Lambertian reflection assumption. Additional analysis showed that the coefficient correlation of the biomass fitting result was improved after the Minnaert+SCS correction, as well as the fitting precision. The R2 has increased by 0.113 to reach 0.869, while the SD (standard deviation of the biomass dropped by 21.2%. Therefore, based on the facts, we conclude that in the region with large topographic relief, the topographical correction is essential to the estimation of the biomass.

  15. Leaf Area Index Estimation in Vineyards from Uav Hyperspectral Data, 2d Image Mosaics and 3d Canopy Surface Models

    Science.gov (United States)

    Kalisperakis, I.; Stentoumis, Ch.; Grammatikopoulos, L.; Karantzalos, K.

    2015-08-01

    The indirect estimation of leaf area index (LAI) in large spatial scales is crucial for several environmental and agricultural applications. To this end, in this paper, we compare and evaluate LAI estimation in vineyards from different UAV imaging datasets. In particular, canopy levels were estimated from i.e., (i) hyperspectral data, (ii) 2D RGB orthophotomosaics and (iii) 3D crop surface models. The computed canopy levels have been used to establish relationships with the measured LAI (ground truth) from several vines in Nemea, Greece. The overall evaluation indicated that the estimated canopy levels were correlated (r2 > 73%) with the in-situ, ground truth LAI measurements. As expected the lowest correlations were derived from the calculated greenness levels from the 2D RGB orthomosaics. The highest correlation rates were established with the hyperspectral canopy greenness and the 3D canopy surface models. For the later the accurate detection of canopy, soil and other materials in between the vine rows is required. All approaches tend to overestimate LAI in cases with sparse, weak, unhealthy plants and canopy.

  16. Efficient retrieval of vegetation leaf area index and canopy clumping factor from satellite data to support pollutant deposition assessments

    International Nuclear Information System (INIS)

    Nikolov, Ned; Zeller, Karl

    2006-01-01

    Canopy leaf area index (LAI) is an important structural parameter of the vegetation controlling pollutant uptake by terrestrial ecosystems. This paper presents a computationally efficient algorithm for retrieval of vegetation LAI and canopy clumping factor from satellite data using observed Simple Ratios (SR) of near-infrared to red reflectance. The method employs numerical inversion of a physics-based analytical canopy radiative transfer model that simulates the bi-directional reflectance distribution function (BRDF). The algorithm is independent of ecosystem type. The method is applied to 1-km resolution AVHRR satellite images to retrieve a geo-referenced data set of monthly LAI values for the conterminous USA. Satellite-based LAI estimates are compared against independent ground LAI measurements over a range of ecosystem types. Verification results suggest that the new algorithm represents a viable approach to LAI retrieval at continental scale, and can facilitate spatially explicit studies of regional pollutant deposition and trace gas exchange. - The paper presents a physics-based algorithm for retrieval of vegetation LAI and canopy-clumping factor from satellite data to assist research of pollutant deposition and trace-gas exchange. The method is employed to derive a monthly LAI dataset for the conterminous USA and verified at a continental scale

  17. Sequential Method with Incremental Analysis Update to Retrieve Leaf Area Index from Time Series MODIS Reflectance Data

    Directory of Open Access Journals (Sweden)

    Jingyi Jiang

    2014-09-01

    Full Text Available High-quality leaf area index (LAI products retrieved from satellite observations are urgently needed for crop growth monitoring and yield estimation, land-surface process simulation and global change studies. In recent years, sequential assimilation methods have been increasingly used to retrieve LAI from time series remote-sensing data. However, the inherent characteristics of these sequential assimilation methods result in temporal discontinuities in the retrieved LAI profiles. In this study, a sequential assimilation method with incremental analysis update (IAU was developed to jointly update model states and parameters and to retrieve temporally continuous LAI profiles from time series Moderate Resolution Imaging Spectroradiometer (MODIS reflectance data. Based on the existing multi-year Global Land Surface Satellite (GLASS LAI product, a dynamic model was constructed to evolve LAI anomalies over time. The sequential assimilation method with an IAU technique takes advantage of the Kalman filter (KF technique to update model parameters, uses the ensemble Kalman filter (EnKF technique to update LAI anomalies recursively from time series MODIS reflectance data and then calculates the temporally continuous LAI values by combining the LAI climatology data. The method was tested over eight Committee on Earth Observing Satellites-Benchmark Land Multisite Analysis and Intercomparison of Products (CEOS-BELMANIP sites with different vegetation types. The results indicate that the sequential method with IAU can precisely reconstruct the seasonal variation patterns of LAI and that the LAI profiles derived from the sequential method with IAU are smooth and continuous.

  18. Voxel tree modeling for estimating leaf area density and woody material volume using 3-D LIDAR data

    Directory of Open Access Journals (Sweden)

    F. Hosoi

    2013-10-01

    Full Text Available In this work, the main focus is on voxel tree modeling using 3-D lidar data for accurate leaf area density (LAD and woody material volume estimation. For more accurate LAD estimation, the voxel model was constructed by combining airborne and portable ground-based lidar data. The profiles obtained by the two types of lidar complemented each other, thus eliminating blind regions and yielding more accurate LAD profiles than could be obtained by using each type of lidar alone. Parts of the LAD profiles that were underestimated even when data from both lidars were combined were interpolated by using a Gaussian function, yielding improved results. A laser beam coverage index, Ω, incorporating the lidar's laser beam settings and a laser beam attenuation factor, was proposed. This index showed general applicability to explain the LAD estimation error for LAD measurements using different types of lidars. In addition, we proposed a method for accurate woody material volume estimation based on a 3-D voxel-based solid modeling of the tree from portable scanning lidar data. The solid model was composed of consecutive voxels that filled the outer surface and the interior of the stem and large branches. By using the model, the woody material volume of not only the whole target tree but also of any part of the target tree can be directly calculated easily and accurately by counting the number of corresponding voxels and multiplying the result by the per-voxel volume.

  19. Response of maize varieties to nitrogen application for leaf area profile, crop growth, yield and yield components

    International Nuclear Information System (INIS)

    Akmal, M.; Hameed-urRehman; Farhatullah; Asim, M.; Akbar, H.

    2010-01-01

    An experiment was conducted at NWFP Agricultural University, Peshawar, to study maize varieties and Nitrogen (N) rates for growth, yield and yield components. Three varieties (Azam, Jalal and Sarhad white) and three N rates (90, 120, 150, kg N ha/sup -1/) were compared. Experiment was conducted in a Randomized Complete Block design; split plot arrangement with 4 replications. Uniform and recommended cultural practices were applied during the crop growth. The results revealed that maize variety 'Jalal' performed relatively better crop growth rate (CGR) and leaf area profile (LAP) at nodal position one to six as compared to the other two varieties (Sarhad white and Azam). This resulted higher radiation use efficiency by the crop canopy at vegetative stage of development and hence contributed higher assimilates towards biomass production. Heavier grains in number and weight were due to higher LAP and taller plants of Jalal which yielded higher in the climate. Nitrogen applications have shown that maize seed yield increase in quadratic fashion with increased N to a plateau level. Considering soil fertility status and cropping system, the 150 kg ha/sup -1/ N application to maize variety Jalal in Peshawar is required for maximum biological and seed production. (author)

  20. Effects of different potting growing media for Petunia grandiflora and Nicotiana alata Link & Otto on photosynthetic capacity, leaf area, and flowering potential

    Directory of Open Access Journals (Sweden)

    Gheorghe Cristian Popescu

    2015-03-01

    Full Text Available Petunia grandiflora Juss. and Nicotiana alata Link & Otto are two of the most widely spread plants on the market for annual potted ornamental plants. In order to identify the most adequate substrate formula we analyzed the effects of different potting growing media used for P. hybrida grandiflora 'Bravo' and N. alata 'Dinamo' on their photosynthetic capacity, leaf area, and flowering potential. Optimization of growing media formula for petunia and ornamental tobacco was performed by preparing four growing media mixing fallow soil (FS, Biolan peat (BP, acid peat (AP, leaf compost (C, and perlite (P in different proportions. The physiological potential of petunia and ornamental tobacco was investigated by photosynthesis and respiration rate and chlorophyll pigments in leaves, while the vegetative and flowering phenological stages were evaluated by number of leaves per plant, leaf area, number of flowers per plant and leaf area/flowers ratio. These measurements were significantly influenced by the different potting growing media used in this study. In the flowering stage, the highest photosynthesis rates (8.612 μmol CO2 m-2 s-1 as well as leaf area (1.766 dm² of petunias were obtained on growing media with 60% biolan peat, 30% acid peat and 10% perlite (BP60-AP30-P10. Flowering responses to growing conditions vary greatly among plants and the biggest number of ornamental tobacco flowers (22 flowers plant-1 was registered as an effect of BP60-AP30-P10 media. Growing media with the BP60-AP30-P10 formula seem to be the most adequate growth substrate to develop profitable crops for petunias and ornamental tobacco with high decorative value.

  1. EQUATIONS FOR LEAF AREA ESTIMATION IN SOME SPECIES ADAPTED TO THE BRAZILIAN SEMI-ARID

    Directory of Open Access Journals (Sweden)

    Paulo Sérgio Lima e Silva

    2007-01-01

    Full Text Available O objetivo deste estudo foi determinar equações do tipo y = a + bx, onde y = área foliar e x = comprimento da folha (C x largura da folha (L, que permitam a estimação da area foliar, a partir de C e L, em nove espécies adaptadas à região Semi-Árida brasileira. Cem folhas foram coletadas do terço mediano da copa de diversas árvores de espécies de folhas simples (Auxemma oncocalyx, Ao; Bauhinia forticata, Bf; Combretum leprosum, Cl e de espécies com folhas compostas: Azadirachta indica (Ai, Caesalpinia bracteosa (Cb, Leucaena leucocephala (Ll, Mimosa caesalpiniifolia (Mc, Schinus terebenthifolius (St, and Tamarindus indica (Ti. Nas espécies com folhas compostas, C, L e A foram medidos em folhas intactas (sem folíolos destacados e nos folíolos destacados. O coeficiente linear foi significativo em Ao e Bf, e não significativo, com folhas intactas em Ai, Cb, St, e Ti. Todos os coeficientes angulares foram diferentes de zero, mas somente em Mc esses coeficientes não diferiram entre si, quando as equações foram ajustadas a partir de folhas intactas e a partir de folíolos destacados. O coeficiente de determinação nas espécies de folhas simples variou de 0,85 to 0,97, enquanto em folhas compostas a variação correspondente foi de 0,28 a 0,93, indicando que a variação na área foliar explicada pela regressão é maior em espécies de folhas simples. Na maioria das espécies de folhas compostas o coeficiente de determinação foi maior quando a estimação foi feita a partir de folhas intactas, exceto em ST.

  2. VIS and NIR land surface albedo sensitivity of the Ent Terrestrial Biosphere Model to forcing leaf area index

    Science.gov (United States)

    Montes, C.; Kiang, N. Y.; Ni-Meister, W.; Yang, W.; Schaaf, C.; Aleinov, I. D.; Jonas, J.; Zhao, F. A.; Yao, T.; Wang, Z.; Sun, Q.; Carrer, D.

    2016-12-01

    Land surface albedo is a major controlling factor in vegetation-atmosphere transfers, modifying the components of the energy budget, the ecosystem productivity and patterns of regional and global climate. General Circulation Models (GCMs) are coupled to Dynamic Global Vegetation Models (DGVMs) to solve vegetation albedo by using simple schemes prescribing albedo based on vegetation classification, and approximations of canopy radiation transport for multiple plant functional types (PFTs). In this work, we aim at evaluating the sensitivity of the NASA Ent Terrestrial Biosphere Model (TBM), a demographic DGVM coupled to the NASA Goddard Institute for Space Studies (GISS) GCM, in estimating VIS and NIR surface albedo by using variable forcing leaf area index (LAI). The Ent TBM utilizes a new Global Vegetation Structure Dataset (GVSD) to account for geographically varying vegetation tree heights and densities, as boundary conditions to the gap-probability based Analytical Clumped Two-Stream (ACTS) canopy radiative transfer scheme (Ni-Meister et al., 2010). Land surface and vegetation characteristics for the Ent GVSD are obtained from a number of earth observation platforms and algorithms, including the Moderate Resolution Imaging Spectroradiometer (MODIS) land cover and plant functional types (PFTs) (Friedl et al., 2010), soil albedo derived from MODIS (Carrer et al., 2014), and vegetation height from the Geoscience Laser Altimeter System (GLAS) on board ICESat (Ice, Cloud, and land Elevation Satellite) (Simard et al., 2011; Tang et al., 2014). Three LAI products are used as input to ACTS/Ent TBM: MODIS MOD15A2H product (Yang et al., 2006), Beijing Normal University LAI (Yuan et al., 2011), and Global Data Sets of Vegetation (LAI3g) (Zhu et al. 2013). The sensitivity of the Ent TBM VIS and NIR albedo to the three LAI products is assessed, compared against the previous GISS GCM vegetation classification and prescribed Lambertian albedoes (Matthews, 1984), and against

  3. Combined Study of Snow Depth Determination and Winter Leaf Area Index Retrieval by Unmanned Aerial Vehicle Photogrammetry

    Science.gov (United States)

    Lendzioch, Theodora; Langhammer, Jakub; Jenicek, Michal

    2017-04-01

    A rapid and robust approach using Unmanned Aerial Vehicle (UAV) digital photogrammetry was performed for evaluating snow accumulation over different small localities (e.g. disturbed forest and open area) and for indirect field measurements of Leaf Area Index (LAI) of coniferous forest within the Šumava National Park, Czech Republic. The approach was used to reveal impacts related to changes in forest and snowpack and to determine winter effective LAI for monitoring the impact of forest canopy metrics on snow accumulation. Due to the advancement of the technique, snow depth and volumetric changes of snow depth over these selected study areas were estimated at high spatial resolution (1 cm) by subtracting a snow-free digital elevation model (DEM) from a snow-covered DEM. Both, downward-looking UAV images and upward-looking digital hemispherical photography (DHP), and additional widely used LAI-2200 canopy analyser measurements were applied to determine the winter LAI, controlling interception and transmitting radiation. For the performance of downward-looking UAV images the snow background instead of the sky fraction was used. The reliability of UAV-based LAI retrieval was tested by taking an independent data set during the snow cover mapping campaigns. The results showed the potential of digital photogrammetry for snow depth mapping and LAI determination by UAV techniques. The average difference obtained between ground-based and UAV-based measurements of snow depth was 7.1 cm with higher values obtained by UAV. The SD of 22 cm for the open area seemed competitive with the typical precision of point measurements. In contrast, the average difference in disturbed forest area was 25 cm with lower values obtained by UAV and a SD of 36 cm, which is in agreement with other studies. The UAV-based LAI measurements revealed the lowest effective LAI values and the plant canopy analyser LAI-2200 the highest effective LAI values. The biggest bias of effective LAI was observed

  4. PYM: a new, affordable, image-based method using a Raspberry Pi to phenotype plant leaf area in a wide diversity of environments.

    Science.gov (United States)

    Valle, Benoît; Simonneau, Thierry; Boulord, Romain; Sourd, Francis; Frisson, Thibault; Ryckewaert, Maxime; Hamard, Philippe; Brichet, Nicolas; Dauzat, Myriam; Christophe, Angélique

    2017-01-01

    Plant science uses increasing amounts of phenotypic data to unravel the complex interactions between biological systems and their variable environments. Originally, phenotyping approaches were limited by manual, often destructive operations, causing large errors. Plant imaging emerged as a viable alternative allowing non-invasive and automated data acquisition. Several procedures based on image analysis were developed to monitor leaf growth as a major phenotyping target. However, in most proposals, a time-consuming parameterization of the analysis pipeline is required to handle variable conditions between images, particularly in the field due to unstable light and interferences with soil surface or weeds. To cope with these difficulties, we developed a low-cost, 2D imaging method, hereafter called PYM. The method is based on plant leaf ability to absorb blue light while reflecting infrared wavelengths. PYM consists of a Raspberry Pi computer equipped with an infrared camera and a blue filter and is associated with scripts that compute projected leaf area. This new method was tested on diverse species placed in contrasting conditions. Application to field conditions was evaluated on lettuces grown under photovoltaic panels. The objective was to look for possible acclimation of leaf expansion under photovoltaic panels to optimise the use of solar radiation per unit soil area. The new PYM device proved to be efficient and accurate for screening leaf area of various species in wide ranges of environments. In the most challenging conditions that we tested, error on plant leaf area was reduced to 5% using PYM compared to 100% when using a recently published method. A high-throughput phenotyping cart, holding 6 chained PYM devices, was designed to capture up to 2000 pictures of field-grown lettuce plants in less than 2 h. Automated analysis of image stacks of individual plants over their growth cycles revealed unexpected differences in leaf expansion rate between

  5. PYM: a new, affordable, image-based method using a Raspberry Pi to phenotype plant leaf area in a wide diversity of environments

    Directory of Open Access Journals (Sweden)

    Benoît Valle

    2017-11-01

    Full Text Available Abstract Background Plant science uses increasing amounts of phenotypic data to unravel the complex interactions between biological systems and their variable environments. Originally, phenotyping approaches were limited by manual, often destructive operations, causing large errors. Plant imaging emerged as a viable alternative allowing non-invasive and automated data acquisition. Several procedures based on image analysis were developed to monitor leaf growth as a major phenotyping target. However, in most proposals, a time-consuming parameterization of the analysis pipeline is required to handle variable conditions between images, particularly in the field due to unstable light and interferences with soil surface or weeds. To cope with these difficulties, we developed a low-cost, 2D imaging method, hereafter called PYM. The method is based on plant leaf ability to absorb blue light while reflecting infrared wavelengths. PYM consists of a Raspberry Pi computer equipped with an infrared camera and a blue filter and is associated with scripts that compute projected leaf area. This new method was tested on diverse species placed in contrasting conditions. Application to field conditions was evaluated on lettuces grown under photovoltaic panels. The objective was to look for possible acclimation of leaf expansion under photovoltaic panels to optimise the use of solar radiation per unit soil area. Results The new PYM device proved to be efficient and accurate for screening leaf area of various species in wide ranges of environments. In the most challenging conditions that we tested, error on plant leaf area was reduced to 5% using PYM compared to 100% when using a recently published method. A high-throughput phenotyping cart, holding 6 chained PYM devices, was designed to capture up to 2000 pictures of field-grown lettuce plants in less than 2 h. Automated analysis of image stacks of individual plants over their growth cycles revealed unexpected

  6. Spatial mapping of leaf area index using hyperspectral remote sensing for hydrological applications with a particular focus on canopy interception

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    H. H. Bulcock

    2010-02-01

    Full Text Available The establishment of commercial forestry plantations in natural grassland vegetation, results in increased transpiration and interception which in turn, results in a streamflow reduction. Methods to quantify this impact typically require LAI as an input into the various equations and process models that are applied. The use of remote sensing technology as a tool to estimate leaf area index (LAI for use in estimating canopy interception is described in this paper. Remote sensing provides a potential solution to effectively monitor the spatial and temporal variability of LAI. This is illustrated using Hyperion hyperspectral imagery and three vegetation indices, namely the normalized difference vegetation index (NDVI, soil adjusted vegetation index (SAVI and Vogelmann index 1 to estimate LAI in a catchment afforested with Eucalyptus, Pinus and Acacia genera in the KwaZulu-Natal midlands of South Africa. Of the three vegetation indices used in this study, it was found that the Vogelmann index 1 was the most robust index with an R2 and root mean square error (RMSE values of 0.7 and 0.3 respectively. However, both NDVI and SAVI could be used to estimate the LAI of 12 year old Pinus patula accurately. If the interception component is to be quantified independently, estimates of maximum storage capacity and canopy interception are required. Thus, the spatial distribution of LAI in the catchment is used to estimate maximum canopy storage capacity in the study area.

  7. Research status of large mode area single polarization active fiber

    Science.gov (United States)

    Xiao, Chun; Zhang, Ge; Yang, Bin-hua; Cheng, Wei-feng; Gu, Shao-yi

    2018-03-01

    As high power fiber laser used more and more widely, to increase the output power of fiber laser and beam quality improvement have become an important goal for the development of high power fiber lasers. The use of large mode fiber is the most direct and effective way to solve the nonlinear effect and fiber damage in the fiber laser power lifting process. In order to reduce the effect of polarization of the fiber laser system, the study found that when introduces a birefringence in the single-mode fiber, the polarization state changes caused by the birefringence is far greater than the random polarization state changes, then the external disturbance is completely submerged, finally the polarization can be controlled and stabilized. Through the fine design of the fiber structure, if the birefringence is high enough to achieve the separation of the two polarization states, the fiber will have a different cut-off mechanism to eliminate polarization which is not need, which will realize single mode single polarization transmission in a band. In this paper, different types of single polarization fiber design are presented and the application of these fibers are also discussed.

  8. Modelos para estimativa da área foliar de Curcuma alismatifolia e Vurcuma zedoaria Leaf area prediction models for Curcuma alismatifolia and Curcuma zedoaria

    Directory of Open Access Journals (Sweden)

    Ana Christina Rossini Pinto

    2008-01-01

    Full Text Available O presente estudo determina modelos para estimativa da área foliar de Curcuma alismatifolia e de Curcuma zedoaria. Para utilização destas espécies como ornamentais, é necessário o estabelecimento de técnicas de produção adequadas. Assim, a determinação da área foliar é importante, pois é usada para avaliar a resposta da planta a fatores ambientais e técnicas culturais. O uso de modelos para estimar a área foliar é um método simples, de boa precisão e não destrutivo. No estádio de floração foram coletadas cem folhas de C.alismatifolia ('Pink' e 'White' e de C.zedoaria. Determinaram-se o comprimento (C e a largura (L máximos e a área foliar real (AFR, com auxílio de integrador de área foliar (LI-3100. Estudaram-se as relações entre a AFR e o C, L e CL (produto do comprimento pela largura da folha, por meio de modelos de regressão linear. Os modelos AFR = 0,59048 CL (C.alismatifolia 'Pink', AFR = 6,08410 + 0,52162 CL (C.alismatifolia 'White' e AFR = 0,70233 CL (C.zedoaria são estatisticamente adequados para estimar a área foliar real.The present work establishes regression models to estimate leaf area of Curcuma alismatifolia and Curcuma zedoaria. To use these of species as ornamental plants is necessary to establish adequate cultivation techniques. Thus, the determination of leaf area is very important, once it is used to evaluate plant response to environmental factors and crop techniques. The use of prediction models to estimate leaf area is a simple, accurate and nondestructive method. At the stage of flowering, a hundred leaves of C.alismatifolia ('Pink' and 'White' and C.zedoaria were collected for each species and cultivar. Maximum length (L, maximum width (W and real leaf area (RLA were measured with a leaf area meter (LI-3100. The relation between RLA and the L, W and the product of length by width (LW, was studied through linear regression models. The models RLA = 0.59048 LW (C.alismatifolia 'Pink', RLA = 6

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

    Science.gov (United States)

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

    2010-05-01

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

  10. Determination of leaf area in the macadamia from linear dimensions of the leaf blade = Determinação da área foliar de macadâmia a partir de dimensões lineares do limbo foliar

    Directory of Open Access Journals (Sweden)

    Edilson Romais Schmildt

    2016-10-01

    Full Text Available Measurement of leaf area is required in various agronomic studies, as it is one of the key measurements for evaluating the growth of plants. The aim of the present study therefore, was to determine the statistical models that best describe leaf area in the macadamia (Macadamia integrifolia cv. HAES 344, from linear dimensions of the length and width of the blade. An experiment was carried out in a completely randomised design, in a scheme of split lots with five replications. Each lot comprised the cardinal points (north, south, east and west of one plant, with the sub-lots comprising three positions on the plant (the lower, middle and upper third. The leaf area was measured using the ImageJ® public-domain software, by analysis of scanned images of the leaves. Equations were estimated from 600 leaves with linear and nonlinear regression models. The resulting equations, together with another four equations quoted in the literature for other cultivars, were validated with a sample of 200 leaves. Statistical modelling of the leaf area in adult plants of the Macadamia cv. HAES 344 can be done using leaves taken from any of the four cardinal points or three heights of the plant. Leaf area is determined by the product of the length (L and the maximum width (W of the leaves as an independent variable. The suggested equation for determining leaf area in leaves of adult plants of the Macadamia cv. HAES 344 is Ŷi = 1.6635+0.6968 WL. = A mensuração da área foliar é requerida em vários estudos agronômicos por ser uma das principais medidas para avaliar o crescimento das plantas. Nesse sentido, objetivou-se com o presente trabalho determinar os modelos estatísticos que melhor descrevem a área foliar de macadâmia (Macadamia integrifolia cv. HAES 344, a partir de dimensões lineares de comprimento e largura do limbo. Um experimento foi realizado em delineamento inteiramente casualizado, em esquema de parcelas subdivididas, com cinco repetições. A

  11. Leaf area of snap bean (Phaseolus vulgaris L. according to leaf dimensionsÁrea foliar de feijão-vagem (Phaseolus vulgaris L. em função de dimensões foliares

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    Marcos Toebe

    2012-12-01

    Full Text Available The aim of this work was to compare the methods of leaf discs and digital photos used to determine the leaf area of snap bean (Phaseolus vulgaris L., with indeterminate growth habit, and model complete leaf area (three leaflets according the length, or width and or the product of length width, for different sizes of leaves. An experiment was conducted in a greenhouse at University Federal of Santa Maria, in Rio Grande do Sul State, Brazil. For this, in 191 leaves, collected 55 days after sowing, it was measured the maximum length and maximum width of central leaflet, and calculated the product of length width. After was determined leaf area of complete leaves (left, central and right leaflets, by the methods of digital photos and leaf discs. Linear regression analysis and correlation were used to compare the methods. The quadratic, potency and linear models of the leaf area as a function of the length, or width, or product of length width were adjusted, and validated by different indicators. In snap beans, the leaf disks and digital photos methods are discordant. The method digital photos adequately represent the leaf limb, regardless of different mass per area exist, and is appropriate for the determination of leaf area. Quadratic model (? = –4.8376 + 1.8908 x + 2.2027 x2, R2 = 0.9901 and potency model (? = 2.5806 x1.9565, R2 = 0.9883 based on the width of central leaflet (x are adequate to estimate complete leaf area (three leaflets, determined by digital photos.O objetivo deste trabalho foi comparar os métodos de discos foliares e de fotos digitais, utilizados para determinar a área foliar de feijão-vagem (Phaseolus vulgaris L. de hábito de crescimento indeterminado, e modelar a área foliar completa (três folíolos em função do comprimento, ou da largura e/ou do produto comprimento vezes largura do folíolo central, de diferentes tamanhos de folhas. O experimento foi conduzido na Universidade Federal de Santa Maria, sob estufa pl

  12. Estimation of Leaf Area Index (LAI) Through the Acquisition of Ground Truth Data in Yosemite National Park

    Science.gov (United States)

    Basson, G.; Hawk, A.; Lue, E.; Ottman, D.; Schiffman, B.; Ghosh, M.; Melton, F.; Schmidt, C.; Skiles, J.

    2007-12-01

    Leaf area index (LAI) is an important indicator of ecosystem health. Remote sensing offers the only feasible method of estimating LAI at global and regional scales. Land managers can efficiently monitor changes in vegetation by using NASA data products such as the MODIS LAI 1km product. To increase confidence in use of the MODIS LAI product in Yosemite National Park, we investigated the accuracy of remotely sensed LAI data and created LAI maps using three optical in-situ instruments: the LAI-2000 instrument, digital hemispheric photography (DHP), and the Tracing Radiation and Architecture of Canopies (TRAC) instrument. We compared our in-situ data with three spectral vegetation indices derived from Landsat Thematic Mapper imagery: Reduced Simple Ratio (RSR), Simple Ratio (SR), and Normalized Difference Vegetation Index (NDVI) to produce models which created LAI maps at 30m and 1km resolution. The strongest correlations occurred between DHP LAI values and RSR. Pixel values from the 1km LAI map were then compared to pixel values from a MODIS LAI map. A strong correlation exists between our in-situ data and MODIS LAI values which confirms its accuracy for use by the National Park Service as a decision support tool in Yosemite. The MODIS LAI product is particularly useful because of its high temporal resolution of 1-2 days and can be used to monitor current and future vegetation changes. The model created using the in-situ data can also be applied to Landsat data to provide thirty years of historical LAI values.

  13. Evaluation of a Phenology-Dependent Response Method for Estimating Leaf Area Index of Rice Across Climate Gradients

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    Bora Lee

    2016-12-01

    Full Text Available Accurate estimate of the seasonal leaf area index (LAI in croplands is required for understanding not only intra- and inter-annual crop development, but also crop management. Lack of consideration in different growth phases in the relationship between LAI and vegetation indices (VI often results in unsatisfactory estimation in the seasonal course of LAI. In this study, we partitioned the growing season into two phases separated by maximum VI ( VI max and applied the general regression model to the data gained from two phases. As an alternative method to capture the influence of seasonal phenological development on the LAI-VI relationship, we developed a consistent development curve method and compared its performance with the general regression approaches. We used the Normalized Difference VI (NDVI and the Enhanced VI (EVI from the rice paddy sites in Asia (South Korea and Japan and Europe (Spain to examine its applicability across different climate conditions and management cycles. When the general regression method was used, separating the season into two phases resulted in no better estimation than the estimation obtained with the entire season observation due to an abrupt change in seasonal LAI occurring during the transition between the before and after VI max . The consistent development curve method reproduced the seasonal patterns of LAI from both NDVI and EVI across all sites better than the general regression method. Despite less than satisfactory estimation of a local LAI max , the consistent development curve method demonstrates improvement in estimating the seasonal course of LAI. The method can aid in providing accurate seasonal LAI as an input into ecological process-based models.

  14. Applying the concept of ecohydrological equilibrium to predict steady-state leaf area index for Australian ecosystems

    Science.gov (United States)

    Yang, J.; Medlyn, B.; De Kauwe, M. G.; Duursma, R.

    2017-12-01

    Leaf Area Index (LAI) is a key variable in modelling terrestrial vegetation, because it has a major impact on carbon, water and energy fluxes. However, LAI is difficult to predict: several recent intercomparisons have shown that modelled LAI differs significantly among models, and between models and satellite-derived estimates. Empirical studies show that long-term mean LAI is strongly related to mean annual precipitation. This observation is predicted by the theory of ecohydrological equilibrium, which provides a promising alternative means to predict steady-state LAI. We implemented this theory in a simple optimisation model. We hypothesized that, when water availability is limited, plants should adjust long-term LAI and stomatal behavior (g1) to maximize net canopy carbon export, under the constraint that canopy transpiration is a fixed fraction of total precipitation. We evaluated the predicted LAI (Lopt) for Australia against ground-based observations of LAI at 135 sites, and continental-scale satellite-derived estimates. For the site-level data, the RMSE of predicted Lopt was 0.14 m2 m-2, which was similar to the RMSE of a comparison of the data against nine-year mean satellite-derived LAI at those sites. Continentally, Lopt had a R2 of over 70% when compared to satellite-derived LAI, which is comparable to the R2 obtained when different satellite products are compared against each other. The predicted response of Lopt to the increase in atmospheric CO2 over the last 30 years also agreed with the estimate based on satellite-derivatives. Our results indicate that long-term equilibrium LAI can be successfully predicted from a simple application of ecohydrological theory. We suggest that this theory could be usefully incorporated into terrestrial vegetation models to improve their predictions of LAI.

  15. Total belowground carbon flux in subalpine forests is related to leaf area index, soil nitrogen, and tree height

    Science.gov (United States)

    Berryman, Erin Michele; Ryan, Michael G.; Bradford, John B.; Hawbaker, Todd J.; Birdsey, R.

    2016-01-01

    In forests, total belowground carbon (C) flux (TBCF) is a large component of the C budget and represents a critical pathway for delivery of plant C to soil. Reducing uncertainty around regional estimates of forest C cycling may be aided by incorporating knowledge of controls over soil respiration and TBCF. Photosynthesis, and presumably TBCF, declines with advancing tree size and age, and photosynthesis increases yet C partitioning to TBCF decreases in response to high soil fertility. We hypothesized that these causal relationships would result in predictable patterns of TBCF, and partitioning of C to TBCF, with natural variability in leaf area index (LAI), soil nitrogen (N), and tree height in subalpine forests in the Rocky Mountains, USA. Using three consecutive years of soil respiration data collected from 22 0.38-ha locations across three 1-km2 subalpine forested landscapes, we tested three hypotheses: (1) annual soil respiration and TBCF will show a hump-shaped relationship with LAI; (2) variability in TBCF unexplained by LAI will be related to soil nitrogen (N); and (3) partitioning of C to TBCF (relative to woody growth) will decline with increasing soil N and tree height. We found partial support for Hypothesis 1 and full support for Hypotheses 2 and 3. TBCF, but not soil respiration, was explained by LAI and soil N patterns (r2 = 0.49), and the ratio of annual TBCF to TBCF plus aboveground net primary productivity (ANPP) was related to soil N and tree height (r2 = 0.72). Thus, forest C partitioning to TBCF can vary even within the same forest type and region, and approaches that assume a constant fraction of TBCF relative to ANPP may be missing some of this variability. These relationships can aid with estimates of forest soil respiration and TBCF across landscapes, using spatially explicit forest data such as national inventories or remotely sensed data products.

  16. 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 (G s ), water- and light-use efficiency and surface-atmosphere coupling of European boreal coniferous forests was explored using eddy-covariance (EC) energy and CO 2 fluxes. The observed scaling relations were then explained using a biophysical multilayer soil-vegetation-atmosphere transfer model as well as by a bulk G s representation. The LAI variations significantly alter radiation regime, within-canopy microclimate, sink/source distributions of CO 2 , H 2 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 G s 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. © 2016 John Wiley & Sons Ltd.

  17. Photon Recollision Probability: a Useful Concept for Cross Scale Consistency Check between Leaf Area Index and Foliage Clumping Products

    Science.gov (United States)

    Pisek, J.

    2017-12-01

    Clumping index (CI) is the measure of foliage aggregation relative to a random distribution of leaves in space. CI is an important factor for the correct quantification of true leaf area index (LAI). Global and regional scale CI maps have been generated from various multi-angle sensors based on an empirical relationship with the normalized difference between hotspot and darkspot (NDHD) index (Chen et al., 2005). Ryu et al. (2011) suggested that accurate calculation of radiative transfer in a canopy, important for controlling gross primary productivity (GPP) and evapotranspiration (ET) (Baldocchi and Harley, 1995), should be possible by integrating CI with incoming solar irradiance and LAI from MODIS land and atmosphere products. It should be noted that MODIS LAI/FPAR product uses internal non-empirical, stochastic equations for parameterization of foliage clumping. This raises a question if integration of the MODIS LAI product with empirically-based CI maps does not introduce any inconsistencies. Here, the consistency is examined independently through the `recollision probability theory' or `p-theory' (Knyazikhin et al., 1998) along with raw LAI-2000/2200 Plant Canopy Analyzer (PCA) data from > 30 sites, surveyed across a range of vegetation types. The theory predicts that the amount of radiation scattered by a canopy should depend only on the wavelength and the spectrally invariant canopy structural parameter p. The parameter p is linked to the foliage clumping (Stenberg et al., 2016). Results indicate that integration of the MODIS LAI product with empirically-based CI maps is feasible. Importantly, for the first time it is shown that it is possible to obtain p values for any location solely from Earth Observation data. This is very relevant for future applications of photon recollision probability concept for global and local monitoring of vegetation using Earth Observation data.

  18. Assimilation of Remotely-Sensed Leaf Area Index into a Dynamic Vegetation Model for Gross Primary Productivity Estimation

    Directory of Open Access Journals (Sweden)

    Rui Ma

    2017-02-01

    Full Text Available Quantitative estimation of the magnitude and variability of gross primary productivity (GPP is required to study the carbon cycle of the terrestrial ecosystem. Using ecosystem models and remotely-sensed data is a practical method for accurately estimating GPP. This study presents a method for assimilating high-quality leaf area index (LAI products retrieved from satellite data into a process-oriented Lund-Potsdam-Jena dynamic global vegetation model (LPJ-DGVM to acquire accurate GPP. The assimilation methods, including the Ensemble Kalman Filter (EnKF and a proper orthogonal decomposition (POD-based ensemble four-dimensional (4D variational assimilation method (PODEn4DVar, incorporate information provided by observations into the model to achieve a better agreement between the model-estimated and observed GPP. The LPJ-POD scheme performs better with a correlation coefficient of r = 0.923 and RMSD of 32.676 gC/m2/month compared with the LPJ-EnKF scheme (r = 0.887, RMSD = 38.531 gC/m2/month and with no data assimilation (r = 0.840, RMSD = 45.410 gC/m2/month. Applying the PODEn4DVar method into LPJ-DGVM for simulating GPP in China shows that the annual amount of GPP in China varied between 5.92 PgC and 6.67 PgC during 2003–2012 with an annual mean of 6.35 PgC/yr. This study demonstrates that integrating remotely-sensed data with dynamic global vegetation models through data assimilation methods has potential in optimizing the simulation and that the LPJ-POD scheme shows better performance in improving GPP estimates, which can provide a favorable way for accurately estimating dynamics of ecosystems.

  19. Spatially Distributed Assimilation of Remotely Sensed Leaf Area Index and Potential Evapotranspiration for Hydrologic Modeling in Wetland Landscapes

    Science.gov (United States)

    Rajib, A.; Evenson, G. R.; Golden, H. E.; Lane, C.

    2017-12-01

    Evapotranspiration (ET), a highly dynamic flux in wetland landscapes, regulates the accuracy of surface/sub-surface runoff simulation in a hydrologic model. Accordingly, considerable uncertainty in simulating ET-related processes remains, including our limited ability to incorporate realistic ground conditions, particularly those involved with complex land-atmosphere feedbacks, vegetation growth, and energy balances. Uncertainty persists despite using high resolution topography and/or detailed land use data. Thus, a good hydrologic model can produce right answers for wrong reasons. In this study, we develop an efficient approach for multi-variable assimilation of remotely sensed earth observations (EOs) into a hydrologic model and apply it in the 1700 km2 Pipestem Creek watershed in the Prairie Pothole Region of North Dakota, USA. Our goal is to employ EOs, specifically Leaf Area Index (LAI) and Potential Evapotranspiration (PET), as surrogates for the aforementioned processes without overruling the model's built-in physical/semi-empirical process conceptualizations. To do this, we modified the source code of an already-improved version of the Soil and Water Assessment Tool (SWAT) for wetland hydrology (Evenson et al. 2016 HP 30(22):4168) to directly assimilate remotely-sensed LAI and PET (obtained from the 500 m and 1 km Moderate Resolution Imaging Spectroradiometer (MODIS) gridded products, respectively) into each model Hydrologic Response Unit (HRU). Two configurations of the model, one with and one without EO assimilation, are calibrated against streamflow observations at the watershed outlet. Spatio-temporal changes in the HRU-level water balance, based on calibrated outputs, are evaluated using MODIS Actual Evapotranspiration (AET) as a reference. It is expected that the model configuration having remotely sensed LAI and PET, will simulate more realistic land-atmosphere feedbacks, vegetation growth and energy balance. As a result, this will decrease simulated

  20. Investigation the Vertical Distribution of Leaf Area and Dry Matter of Sweet Basil (Ocimum basilicum L., Borage (Borago officinalis L. and Cover Crops in Competition with Weeds

    Directory of Open Access Journals (Sweden)

    zeinab shirzadi margavi

    2017-10-01

    Full Text Available Introduction Distribution of leaf area and dry matter are the effective factors that influence on absorption the radiation, evaporation and transpiration of canopy and eventually dry matter accumulation and grain yield in plants. Plant canopy is the spatial arrangement of shoots in a plant population. In plant canopy, leaves are responsible for radiation absorption and gas exchange with the outside. Stem and branches arrange photosynthetic organs somehow, which gas exchange and light distribution best done. The effect of canopy structure on gas exchange and absorption of radiation in plant communities caused detailed study of the canopy structure to be more important. Materials and methods In order to investigate the vertical distribution of leaf area and dry matter of borage and sweet basil in competition with weeds by cover crops treatments, a field experiment was carried out in a randomized complete block design with 8 treatments and 3 replications in Agricultural Sciences and Natural Resources University of Sari in 2013. Treatments were cover crops mung bean (Vigna radiata L. and Persian clover (Trifolium resupinatum L. in the rows between the sweet basil (Ocimum basilicum L. and borage (Borago officinalis L.. Moreover, in order to evaluate the effectiveness of cover crops to control weeds, pure stand of sweet basil and borage in terms of weeding and no weed controls per replicates were used. Each plot was included 5 rows of medicinal plants. Cover crop inter-seeded simultaneously in the main crop. Estimation of leaf area and dry matter of each plant in different canopy layers (0-20, 20-40, 40-60, 80.100, 100-120 and 120-140 cm were done after 75 planting days, with 1 m × 1 m quadrate per plot. For this purpose a vertical card board frame marked in 20-cm increments was used in the field as a guide to cut standing plants (crops, cover crops and weeds into 20-cm strata increments (Mosier & Oliver, 1995. All samples were transferred to the

  1. Multi-Spectral Imaging from an Unmanned Aerial Vehicle Enables the Assessment of Seasonal Leaf Area Dynamics of Sorghum Breeding Lines

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    Andries B. Potgieter

    2017-09-01

    Full Text Available Genetic improvement in sorghum breeding programs requires the assessment of adaptation traits in small-plot breeding trials across multiple environments. Many of these phenotypic assessments are made by manual measurement or visual scoring, both of which are time consuming and expensive. This limits trial size and the potential for genetic gain. In addition, these methods are typically restricted to point estimates of particular traits, such as leaf senescence or flowering and do not capture the dynamic nature of crop growth. In water-limited environments in particular, information on leaf area development over time would provide valuable insight into water use and adaptation to water scarcity during specific phenological stages of crop development. Current methods to estimate plant leaf area index (LAI involve destructive sampling and are not practical in breeding. Unmanned aerial vehicles (UAV and proximal-sensing technologies open new opportunities to assess these traits multiple times in large small-plot trials. We analyzed vegetation-specific crop indices obtained from a narrowband multi-spectral camera on board a UAV platform flown over a small pilot trial with 30 plots (10 genotypes randomized within 3 blocks. Due to variable emergence we were able to assess the utility of these vegetation indices to estimate canopy cover and LAI over a large range of plant densities. We found good correlations between the Normalized Difference Vegetation Index (NDVI and the Enhanced Vegetation Index (EVI with plant number per plot, canopy cover and LAI both during the vegetative growth phase (pre-anthesis and at maximum canopy cover shortly after anthesis. We also analyzed the utility of time-sequence data to assess the senescence pattern of sorghum genotypes known as fast (senescent or slow senescing (stay-green types. The Normalized Difference Red Edge (NDRE index which estimates leaf chlorophyll content was most useful in characterizing the leaf area

  2. Multi-Spectral Imaging from an Unmanned Aerial Vehicle Enables the Assessment of Seasonal Leaf Area Dynamics of Sorghum Breeding Lines

    Science.gov (United States)

    Potgieter, Andries B.; George-Jaeggli, Barbara; Chapman, Scott C.; Laws, Kenneth; Suárez Cadavid, Luz A.; Wixted, Jemima; Watson, James; Eldridge, Mark; Jordan, David R.; Hammer, Graeme L.

    2017-01-01

    Genetic improvement in sorghum breeding programs requires the assessment of adaptation traits in small-plot breeding trials across multiple environments. Many of these phenotypic assessments are made by manual measurement or visual scoring, both of which are time consuming and expensive. This limits trial size and the potential for genetic gain. In addition, these methods are typically restricted to point estimates of particular traits, such as leaf senescence or flowering and do not capture the dynamic nature of crop growth. In water-limited environments in particular, information on leaf area development over time would provide valuable insight into water use and adaptation to water scarcity during specific phenological stages of crop development. Current methods to estimate plant leaf area index (LAI) involve destructive sampling and are not practical in breeding. Unmanned aerial vehicles (UAV) and proximal-sensing technologies open new opportunities to assess these traits multiple times in large small-plot trials. We analyzed vegetation-specific crop indices obtained from a narrowband multi-spectral camera on board a UAV platform flown over a small pilot trial with 30 plots (10 genotypes randomized within 3 blocks). Due to variable emergence we were able to assess the utility of these vegetation indices to estimate canopy cover and LAI over a large range of plant densities. We found good correlations between the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI) with plant number per plot, canopy cover and LAI both during the vegetative growth phase (pre-anthesis) and at maximum canopy cover shortly after anthesis. We also analyzed the utility of time-sequence data to assess the senescence pattern of sorghum genotypes known as fast (senescent) or slow senescing (stay-green) types. The Normalized Difference Red Edge (NDRE) index which estimates leaf chlorophyll content was most useful in characterizing the leaf area dynamics

  3. Multi-Spectral Imaging from an Unmanned Aerial Vehicle Enables the Assessment of Seasonal Leaf Area Dynamics of Sorghum Breeding Lines.

    Science.gov (United States)

    Potgieter, Andries B; George-Jaeggli, Barbara; Chapman, Scott C; Laws, Kenneth; Suárez Cadavid, Luz A; Wixted, Jemima; Watson, James; Eldridge, Mark; Jordan, David R; Hammer, Graeme L

    2017-01-01

    Genetic improvement in sorghum breeding programs requires the assessment of adaptation traits in small-plot breeding trials across multiple environments. Many of these phenotypic assessments are made by manual measurement or visual scoring, both of which are time consuming and expensive. This limits trial size and the potential for genetic gain. In addition, these methods are typically restricted to point estimates of particular traits, such as leaf senescence or flowering and do not capture the dynamic nature of crop growth. In water-limited environments in particular, information on leaf area development over time would provide valuable insight into water use and adaptation to water scarcity during specific phenological stages of crop development. Current methods to estimate plant leaf area index (LAI) involve destructive sampling and are not practical in breeding. Unmanned aerial vehicles (UAV) and proximal-sensing technologies open new opportunities to assess these traits multiple times in large small-plot trials. We analyzed vegetation-specific crop indices obtained from a narrowband multi-spectral camera on board a UAV platform flown over a small pilot trial with 30 plots (10 genotypes randomized within 3 blocks). Due to variable emergence we were able to assess the utility of these vegetation indices to estimate canopy cover and LAI over a large range of plant densities. We found good correlations between the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI) with plant number per plot, canopy cover and LAI both during the vegetative growth phase (pre-anthesis) and at maximum canopy cover shortly after anthesis. We also analyzed the utility of time-sequence data to assess the senescence pattern of sorghum genotypes known as fast (senescent) or slow senescing (stay-green) types. The Normalized Difference Red Edge (NDRE) index which estimates leaf chlorophyll content was most useful in characterizing the leaf area dynamics

  4. Effect of Salinity Stress and Iron Spraying on Leaf Area Index, Light Absorption and Relations with Yield in Sunflower (Helianthus annuns L.)

    OpenAIRE

    M.H Shariatmadari; G.R Zamani; M.H Sayari

    2012-01-01

    Salinity stress results to decreasing leaf area index (LAI) and light absorption in plant leading in yield decrease. In order to study effect of salinity and iron sulphate on LAI, absorbed light percentage and yield of sunflower (Euroflor cultivar), an experiment was carried out as split plot based on complete randomized block design with four replications in the Research Field of University of Birjand on 2009. In this experiment main plots were different levels of irrigation with saline wate...

  5. Evaluation of Indirect Measurement Method of Seasonal Patterns of Leaf Area Index in a High-Density Short Rotation Coppice Culture of Poplar

    Czech Academy of Sciences Publication Activity Database

    Tripathi, Abishek; Fischer, Milan; Orság, Matěj; Marek, Michal V.; Žalud, Zdeněk; Trnka, Miroslav

    2016-01-01

    Roč. 64, č. 2 (2016), s. 549-556 ISSN 1211-8516 R&D Projects: GA MŠk(CZ) LD13030; GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk(CZ) EE2.3.20.0248 Institutional support: RVO:67179843 Keywords : SunScan Plant Canopy Analyzer * litterfall * specific leaf area * poplar clone J-105 Subject RIV: GC - Agronomy

  6. Variation Trend of Leaf Area Index, Yield and Yield Components of Green Beans (Phaseolous vulgaris L. by Using Zinc Sulfate and Nitrogen

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    Sh. Lack

    2016-01-01

    Full Text Available Proper nutrition of plant is one of the most important factors to improve both quality and quantiy of crop yields. Accordingly, the effect of different levels of zinc and nitrogen on leaf area index, yield and yield components of green beans investigated in the summer of 2012. The experiment used was a split plot in randomized complete block design with three replications in the Dezful. In this study, the main plots consisted of four nitrogen rates of urea (0, 30, 60 and 90 kgha-1, and sub plots of four levels of zinc sulfate (0, 10, 20 and 30 kg.ha-1. The results showed that application of 90 N kg.ha-1 increased leaf area index, plant dry matter, grain yield, biological yield, harvest index and protein content. Use of zinc sulfate at the rate of 20 kg.ha-1 was superior in grain yield and yield components. The highest leaf area index, grain and biological yields harvest index and protein content were achieved by application of 90 kg nitrogen and 20 kg of zinc sulfate per hectare. It seems that the use of zinc with appropriate rates, through its involvement in physiological processes and nitrogen metabolism in plants as an essential element, accelerates green beans growth processes and increases green bean yield.

  7. Effects of extreme drought on specific leaf area of grassland species: A meta-analysis of experimental studies in temperate and sub-Mediterranean systems.

    Science.gov (United States)

    Wellstein, Camilla; Poschlod, Peter; Gohlke, Andreas; Chelli, Stefano; Campetella, Giandiego; Rosbakh, Sergey; Canullo, Roberto; Kreyling, Jürgen; Jentsch, Anke; Beierkuhnlein, Carl

    2017-06-01

    Here, we conducted a meta-analysis of experimental drought manipulation studies using rainout shelters in five sites of natural grassland ecosystems of Europe. The single studies assess the effects of extreme drought on the intraspecific variation of the specific leaf area (SLA), a proxy of plant growth. We evaluate and compare the effect size of the SLA response for the functional groups of forbs and grasses in temperate and sub-Mediterranean systems. We hypothesized that the functional groups of grasses and forbs from temperate grassland systems have different strategies in short-term drought response, measured as adjustment of SLA, with SLA-reduction in grasses and SLA-maintenance in forbs. Second, we hypothesized that grasses and forbs from sub-Mediterranean systems do not differ in their drought response as both groups maintain their SLA. We found a significant decrease of SLA in grasses of the temperate systems in response to drought while SLA of forbs showed no significant response. Lower SLA is associated with enhanced water-use efficiency under water stress and thus can be seen as a strategy of phenotypic adjustment. By contrast, in the sub-Mediterranean systems, grasses significantly increased their SLA in the drought treatment. This result points towards a better growth performance of these grasses, which is most likely related to their strategy to allocate resources to belowground parts. The observed SLA reduction of forbs is most likely a direct drought response given that competitive effect of grasses is unlikely due to the scanty vegetation cover. We point out that phenotypic adjustment is an important driver of short-term functional plant response to climatic extremes such as drought. Differential reactions of functional groups have to be interpreted against the background of the group's evolutionary configuration that can differ between climatic zones. © 2017 John Wiley & Sons Ltd.

  8. Estimative of Black Pepper leaf area with basis on the leaf blade linear dimension Estimativa da área foliar de pimenta do reino a partir de dimensões lineares do limbo foliar

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    Fábio Luiz Partelli

    2007-10-01

    Full Text Available This research was aimed at establishing regression equations to estimate black pepper (Piper nigrum leaf area based on linear leaf measures. Different black pepper varieties where growth on the field, four different size leaves were collected per plant with a total of 52 leaves to establish the regression equation and 28 to validate the equation for each variety (Bragantina, Laçará, Guajarina e Cingapura. Leaf midrib length (LML, maximum leaf broad width (MLBW and leaf area (LA were measured. Pearson's linear correlation coefficients were determined between observed and predicted measures with the observed LA, besides estimating the linear regression equation for each variety. The equations best-fitted to estimate LA based on circumscript rectangle were: 1 LA = 2.2689 + 0.6900 x LML x MLBW; 2 LA = 1.6402 + 0.6816 x LML x MLBW; 3 LA = 1.4942 + 0.6215 x LML x MLBW and 4 LA = 0.7467 + 0.6735 x LML x MLBW, for Bragantina, Laçará, Guajarina and Cingapura varieties respectively. For all equations predicted values had high correlation coefficient with observed values thus showing that these equations must be variety specific and that they are appropriate for black pepper leaf area estimative.O objetivo deste trabalho foi estabelecer equações de regressão para estimar a área foliar de diferentes variedades de pimenta-do-reino (Piper nigrum cultivadas no campo, a partir de medidas lineares de folhas. Foram coletadas quatro folhas por planta, de tamanhos diferentes, totalizando 52 folhas, para estabelecer a equação de regressão e 28 para validar a equação para cada variedade (Bragantina, Laçará, Guajarina e Cingapura. Procederam-se às medições do comprimento da nervura central (LML, da maior largura do limbo foliar (MLBW e da área foliar (LA. Determinaram-se os coeficientes de correlação linear de Pearson entre as medidas mensuráveis e preditas com a LA observada, além de estimarem-se as equações de regressão linear para cada

  9. Modelos de determinação não-destrutiva da área foliar em girassol Models for estimating leaf area in sunflower

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    Ivan Carlos Maldaner

    2009-08-01

    Full Text Available Os objetivos deste trabalho foram obter e testar modelos matemáticos de estimativa da área do limbo foliar em função das suas dimensões lineares para o girassol. Foram conduzidos dois experimentos na área experimental do departamento de Fitotecnia da Universidade Federal de Santa Maria. As plantas de girassol foram coletadas a partir dos 27 dias após emergência (DAE. A área foliar (AF foi determinada pelo método dos discos. Ajustaram-se modelos lineares, quadráticos, cúbicos e potenciais entre área foliar e comprimento ou largura e seus produtos (comprimento*largura, sendo eliminados os que apresentaram coeficiente de determinação menor do que 0,90. A estatística utilizada para avaliar o desempenho dos modelos foi a raiz do quadrado médio do erro (RQME. Os modelos que melhor se ajustaram aos dados foram: potência, quadrático e cúbico, considerando a largura como variável independente. A área foliar de girassol pode ser estimada com o modelo potência, por ser o mais preciso, e a largura da folha.The objective of this study was to obtain and to numerical models to estimate the leaf area in function leaves linear dimension in sunflower. Two experiments were conducted at the experimental area of the Plant Science Department of the Federal University of Santa Maria, Santa Maria, RS, Brazil. Plants of sunflower were collected starting 27 days after emergency (DAE. The disks method was used to determine the leaf area (LA. Leaves were dried in oven at 65°C until constant weight. Linear, quadratic, cubic and power models between leaf area and length or width, and the product (length * width, were fitted. Models that apresented coefficient of determination lower than 0.90 were not selected. The statistic used to evaluate the performance of the models was the root mean square error (RQME. Models that had the best fit were power, quadratic and cubic using blade width as the independent variable. Leaf area in sunflower can be

  10. Multiscale assessment of green leaf area in a semi-arid rangeland with a small unmanned aerial vehicle

    Science.gov (United States)

    Spatial variability in green leaf cover of a western rangeland was studied by comparing field measurements on 50 m crossed transects to aerial and satellite imagery. The normalized difference vegetation index was calculated for multiple 2 cm resolution images collected over the field transects with ...

  11. Exploring the Potential of WorldView-2 Red-Edge Band-Based Vegetation Indices for Estimation of Mangrove Leaf Area Index with Machine Learning Algorithms

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    Yuanhui Zhu

    2017-10-01

    Full Text Available To accurately estimate leaf area index (LAI in mangrove areas, the selection of appropriate models and predictor variables is critical. However, there is a major challenge in quantifying and mapping LAI using multi-spectral sensors due to the saturation effects of traditional vegetation indices (VIs for mangrove forests. WorldView-2 (WV2 imagery has proven to be effective to estimate LAI of grasslands and forests, but the sensitivity of its vegetation indices (VIs has been uncertain for mangrove forests. Furthermore, the single model may exhibit certain randomness and instability in model calibration and estimation accuracy. Therefore, this study aims to explore the sensitivity of WV2 VIs for estimating mangrove LAI by comparing artificial neural network regression (ANNR, support vector regression (SVR and random forest regression (RFR. The results suggest that the RFR algorithm yields the best results (RMSE = 0.45, 14.55% of the average LAI, followed by ANNR (RMSE = 0.49, 16.04% of the average LAI, and then SVR (RMSE = 0.51, 16.56% of the average LAI algorithms using 5-fold cross validation (CV using all VIs. Quantification of the variable importance shows that the VIs derived from the red-edge band consistently remain the most important contributor to LAI estimation. When the red-edge band-derived VIs are removed from the models, estimation accuracies measured in relative RMSE (RMSEr decrease by 3.79%, 2.70% and 4.47% for ANNR, SVR and RFR models respectively. VIs derived from red-edge band also yield better accuracy compared with other traditional bands of WV2, such as near-infrared-1 and near-infrared-2 band. Furthermore, the estimated LAI values vary significantly across different mangrove species. The study demonstrates the utility of VIs of WV2 imagery and the selected machine-learning algorithms in developing LAI models in mangrove forests. The results indicate that the red-edge band of WV2 imagery can help alleviate the saturation

  12. Comparison of the Spatial Characteristics of Four Remotely Sensed Leaf Area Index Products over China: Direct Validation and Relative Uncertainties

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    Xinlu Li

    2018-01-01

    Full Text Available Leaf area index (LAI is a key input for many land surface models, ecological models, and yield prediction models. In order to make the model simulation and/or prediction more reliable and applicable, it is crucial to know the characteristics and uncertainties of remotely sensed LAI products before they are input into models. In this study, we conducted a comparison of four global remotely sensed LAI products—Global Land Surface Satellite (GLASS, Global LAI Product of Beijing Normal University (GLOBALBNU, Global LAI Map of Chinese Academy of Sciences (GLOBMAP, and Moderate-resolution Imaging Spectrometer (MODIS LAI, while the former three products are newly developed by three Chinese research groups on the basis of the MODIS land reflectance product over China between 2001 and 2011. Direct validation by comparing the four products to ground LAI observations both globally and over China demonstrates that GLASS LAI shows the best performance, with R2 = 0.70 and RMSE = 0.96 globally and R2 = 0.94 and RMSE = 0.61 over China; MODIS performs worst (R2 = 0.55, RMSE = 1.23 globally and R2 = 0.03, RMSE = 2.12 over China, and GLOBALBNU and GLOBMAP performs moderately. Comparison of the four products shows that they are generally consistent with each other, giving the smallest spatial correlation coefficient of 0.7 and the relative standard deviation around the order of 0.3. Compared with MODIS LAI, GLOBALBNU LAI is the most similar, followed by GLASS LAI and GLOBMAP. Large differences mainly occur in southern regions of China. LAI difference analysis indicates that evergreen needleleaf forest (ENF, woody savannas (SAV biome types and temperate dry hot summer, temperate warm summer dry winter and temperate hot summer no dry season climate types correspond to high standard deviation, while ENF and grassland (GRA biome types and temperate warm summer dry winter and cold dry winter warm summer climate types are responsible for the large relative standard

  13. Satellite Leaf Area Index: global scale analysis of the tendencies per vegetation type over the last 17 years

    Science.gov (United States)

    Munier, Simon; Carrer, Dominique; Planque, Carole; Albergel, Clément; Calvet, Jean-Christophe

    2017-04-01

    The dynamics of terrestrial vegetation is greatly altered by global environmental change. In particular, changes in vegetation greenness have been related to multiple biogeochemical drivers (such as CO2 concentration in the atmosphere or changes in temperature and precipitation) and land-use effects (fertilization, irrigation, etc.). Impacts of such drivers on the vegetation dynamics and Leaf Area Index (LAI) are expected to depend on the region of the globe but also on the vegetation type. With recent advances in remote sensing techniques, it has become possible to study the LAI variations at the global scale and in a consistent way over the last decades. For instance, the BIOPAR dataset from the Copernicus Global Land Service project (http://land.copernicus.eu/global/) provides satellite derived LAI every 10 days at a 1 km spatial resolution since 1999. Yet, in spite of the high spatial resolution of such datasets, they do not allow to discriminate between vegetation types over mixed pixels. In this study, we first developed a Kalman Filtering (KF) approach to disaggregate the satellite driven LAI from BIOPAR over nine main vegetation types, including broadleaves, conifers and grassland. We used as a prior information data from the ECOCLIMAP land cover database. Temporal fluctuations of the satellite signal are assumed to be due to changes of the properties of the dominant vegetation types in the pixel grid. The analysed LAI of the dominant cover type absorbs most of the temporal fluctuations that exist in the total LAI. This KF approach permits to separate the individual LAI of different vegetation types that co-exist in a grid pixel. Same approach has been developed by Carrer et al. (2013) to derive bare soil and vegetation albedos from total surface albedo products. In a second step a trend analysis has been conducted using the Mann-Kendall test for each vegetation type independently over the period 1999-2015 and comparisons with the original aggregated LAI

  14. Comparison of UAV and WorldView-2 imagery for mapping leaf area index of mangrove forest

    Science.gov (United States)

    Tian, Jinyan; Wang, Le; Li, Xiaojuan; Gong, Huili; Shi, Chen; Zhong, Ruofei; Liu, Xiaomeng

    2017-09-01

    Unmanned Aerial Vehicle (UAV) remote sensing has opened the door to new sources of data to effectively characterize vegetation metrics at very high spatial resolution and at flexible revisit frequencies. Successful estimation of the leaf area index (LAI) in precision agriculture with a UAV image has been reported in several studies. However, in most forests, the challenges associated with the interference from a complex background and a variety of vegetation species have hindered research using UAV images. To the best of our knowledge, very few studies have mapped the forest LAI with a UAV image. In addition, the drawbacks and advantages of estimating the forest LAI with UAV and satellite images at high spatial resolution remain a knowledge gap in existing literature. Therefore, this paper aims to map LAI in a mangrove forest with a complex background and a variety of vegetation species using a UAV image and compare it with a WorldView-2 image (WV2). In this study, three representative NDVIs, average NDVI (AvNDVI), vegetated specific NDVI (VsNDVI), and scaled NDVI (ScNDVI), were acquired with UAV and WV2 to predict the plot level (10 × 10 m) LAI. The results showed that AvNDVI achieved the highest accuracy for WV2 (R2 = 0.778, RMSE = 0.424), whereas ScNDVI obtained the optimal accuracy for UAV (R2 = 0.817, RMSE = 0.423). In addition, an overall comparison results of the WV2 and UAV derived LAIs indicated that UAV obtained a better accuracy than WV2 in the plots that were covered with homogeneous mangrove species or in the low LAI plots, which was because UAV can effectively eliminate the influence from the background and the vegetation species owing to its high spatial resolution. However, WV2 obtained a slightly higher accuracy than UAV in the plots covered with a variety of mangrove species, which was because the UAV sensor provides a negative spectral response function(SRF) than WV2 in terms of the mangrove LAI estimation.

  15. An Extended Fourier Approach to Improve the Retrieved Leaf Area Index (LAI in a Time Series from an Alpine Wetland

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    Xingwen Quan

    2014-01-01

    Full Text Available An extended Fourier approach was presented to improve the retrieved leaf area index (LAIr of herbaceous vegetation in a time series from an alpine wetland. The retrieval was performed from the Aqua MODIS 8-day composite surface reflectance product (MYD09Q1 from day of year (DOY 97 to 297 using a look-up table (LUT based inversion of a two-layer canopy reflectance model (ACRM. To reduce the uncertainty (the ACRM inversion is ill-posed, we used NDVI and NIR images to reduce the influence of the soil background and the priori information to constrain the range of sensitive ACRM parameters determined using the Sobol’s method. Even so the uncertainty caused the LAIr versus time curve to oscillate. To further reduce the uncertainty, a Fourier model was fitted using the periodically LAIr results, obtaining LAIF. We note that the level of precision of the LAIF potentially may increase through removing singular points or decrease if the LAIr data were too noisy. To further improve the precision level of the LAIr, the Fourier model was extended by considering the LAIr uncertainty. The LAIr, the LAI simulated using the Fourier model, and the LAI simulated using the extended Fourier approach (LAIeF were validated through comparisons with the field measured LAI. The R2 values were 0.68, 0.67 and 0.72, the residual sums of squares (RSS were 3.47, 3.42 and 3.15, and the root-mean-square errors (RMSE were 0.31, 0.30 and 0.29, respectively, on DOY 177 (early July 2011. In late August (DOY 233, the R2 values were 0.73, 0.77 and 0.79, the RSS values were 38.96, 29.25 and 27.48, and the RMSE values were 0.94, 0.81 and 0.78, respectively. The results demonstrate that the extended Fourier approach has the potential to increase the level of precision of estimates of the time varying LAI.

  16. Extracting Leaf Area Index by Sunlit Foliage Component from Downward-Looking Digital Photography under Clear-Sky Conditions

    Directory of Open Access Journals (Sweden)

    Yelu Zeng

    2015-10-01

    Full Text Available The development of near-surface remote sensing requires the accurate extraction of leaf area index (LAI from networked digital cameras under all illumination conditions. The widely used directional gap fraction model is more suitable for overcast conditions due to the difficulty to discriminate the shaded foliage from the shadowed parts of images acquired on sunny days. In this study, a new LAI extraction method by the sunlit foliage component from downward-looking digital photography under clear-sky conditions is proposed. In this method, the sunlit foliage component was extracted by an automated image classification algorithm named LAB2, the clumping index was estimated by a path length distribution-based method, the LAD and G function were quantified by leveled digital images and, eventually, the LAI was obtained by introducing a geometric-optical (GO model which can quantify the sunlit foliage proportion. The proposed method was evaluated at the YJP site, Canada, by the 3D realistic structural scene constructed based on the field measurements. Results suggest that the LAB2 algorithm makes it possible for the automated image processing and the accurate sunlit foliage extraction with the minimum overall accuracy of 91.4%. The widely-used finite-length method tends to underestimate the clumping index, while the path length distribution-based method can reduce the relative error (RE from 7.8% to 6.6%. Using the directional gap fraction model under sunny conditions can lead to an underestimation of LAI by (1.61; 55.9%, which was significantly outside the accuracy requirement (0.5; 20% by the Global Climate Observation System (GCOS. The proposed LAI extraction method has an RMSE of 0.35 and an RE of 11.4% under sunny conditions, which can meet the accuracy requirement of the GCOS. This method relaxes the required diffuse illumination conditions for the digital photography, and can be applied to extract LAI from downward-looking webcam images

  17. [Comparison of precision in retrieving soybean leaf area index based on multi-source remote sensing data].

    Science.gov (United States)

    Gao, Lin; Li, Chang-chun; Wang, Bao-shan; Yang Gui-jun; Wang, Lei; Fu, Kui

    2016-01-01

    With the innovation of remote sensing technology, remote sensing data sources are more and more abundant. The main aim of this study was to analyze retrieval accuracy of soybean leaf area index (LAI) based on multi-source remote sensing data including ground hyperspectral, unmanned aerial vehicle (UAV) multispectral and the Gaofen-1 (GF-1) WFV data. Ratio vegetation index (RVI), normalized difference vegetation index (NDVI), soil-adjusted vegetation index (SAVI), difference vegetation index (DVI), and triangle vegetation index (TVI) were used to establish LAI retrieval models, respectively. The models with the highest calibration accuracy were used in the validation. The capability of these three kinds of remote sensing data for LAI retrieval was assessed according to the estimation accuracy of models. The experimental results showed that the models based on the ground hyperspectral and UAV multispectral data got better estimation accuracy (R² was more than 0.69 and RMSE was less than 0.4 at 0.01 significance level), compared with the model based on WFV data. The RVI logarithmic model based on ground hyperspectral data was little superior to the NDVI linear model based on UAV multispectral data (The difference in E(A), R² and RMSE were 0.3%, 0.04 and 0.006, respectively). The models based on WFV data got the lowest estimation accuracy with R2 less than 0.30 and RMSE more than 0.70. The effects of sensor spectral response characteristics, sensor geometric location and spatial resolution on the soybean LAI retrieval were discussed. The results demonstrated that ground hyperspectral data were advantageous but not prominent over traditional multispectral data in soybean LAI retrieval. WFV imagery with 16 m spatial resolution could not meet the requirements of crop growth monitoring at field scale. Under the condition of ensuring the high precision in retrieving soybean LAI and working efficiently, the approach to acquiring agricultural information by UAV remote

  18. The leaf litter ant fauna of an Atlantic Forest area in the Cantareira State Park – São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Andre Soliva Ribeiro

    2005-11-01

    Full Text Available The present work surveys the leaf litter ant fauna of an Atlantic Forest area in Cantareira State Park – SP, Brazil as a complement to the project “Richness and diversity of Hymenoptera and Isoptera along a latitudinal gradient in the Atlantic Forest – the eastern Brazilian rain forest” that forms part of the BIOTA-FAPESP program. The general protocol of the project was to collect 50 leaf litter samples of 1 m2 which were then sifted and submitted to Winkler extractors for 48 hours. Sixty-two species of 25 genera in eight ant subfamilies were collected. Myrmicinae was the richest with 39 species, followed by Ponerinae (14, Ectatomminae, Heteroponerinae and Formicinae (two species each, Amblyoponinae, Proceratiinae and Dolichoderinae (one species each. The richest genera were Solenopsis and Hypoponera (12 morph-species each, and Pheidole (eight. Richness estimators indicated that the total number of species in the area should be between 68 and 85, in a confidence interval of 95%. In comparison, other locations of the evergreen Atlantic Forest have shown a significantly higher richness. Our hypothesis is that the proximity of regions of great urban concentration, allied to the factors that act on a local scale, modifies the structure of the local community of leaf litter ants.

  19. Undecomposed Twigs in the Leaf Litter as Nest-Building Resources for Ants (Hymenoptera: Formicidae in Areas of the Atlantic Forest in the Southeastern Region of Brazil

    Directory of Open Access Journals (Sweden)

    Tae Tanaami Fernandes

    2012-01-01

    Full Text Available In tropical forests, the leaf-litter stratum exhibits one of the greatest abundances of ant species. This diversity is associated with the variety of available locations for nest building. Ant nests can be found in various microhabitats, including tree trunks and fallen twigs in different stages of decomposition. In this study, we aimed to investigate undecomposed twigs as nest-building resources in the leaf litter of dense ombrophilous forest areas in the southeastern region of Brazil. Demographic data concerning the ant colonies, the physical characteristics of the nests, and the population and structural of the forest were observed. Collections were performed manually over four months in closed canopy locations that did not have trails or flooded areas. A total of 294 nests were collected, and 34 ant species were recorded. Pheidole, Camponotus, and Hypoponera were the richest genera observed; these genera were also among the most populous and exhibited the greatest abundance of nests. We found no association between population size and nest diameter. Only tree cover influenced the nest abundance and species richness. Our data indicate that undecomposed twigs may be part of the life cycle of many species and are important for maintaining ant diversity in the leaf litter.

  20. A RVI/LAI-reference curve to detect N stress and guide N fertigation using combined information from spectral reflectance and leaf area measurements in potato

    DEFF Research Database (Denmark)

    Zhenjiang, Zhou; Plauborg, Finn; Thomsen, Anton Gårde

    2017-01-01

    strip in the field. The reference curve method was derived from the integrated information of ratio vegetation index (RVI) and leaf area index (LAI), which were obtained from field experimental potato crops. Different N treatments received 42 kg N ha−1 at planting and, subsequently, the rest of N......More user-friendly methods are needed to detect crop N status/stress and guide the timing of in-season N application. In the current study, a reference curve method of detecting N stress was proposed to remedy practical problems of methods that require leaf sampling or maintaining a N sufficient...... function, which was independent of season. The treatments where N fertigation was stopped before reaching 180 kg N ha−1 started to deviate from the 95% confidence interval of the reference curve about 10 days after N-fertigation was stopped. This corresponded to 10–20 kg ha−1 difference in total plant N...

  1. Modelo para determinção da área foliar de Kalanchoe blossfeldiana Poelln Model for leaf area determination in Kalanchoe blossfeldiana Poelln

    Directory of Open Access Journals (Sweden)

    Marcia Xavier Peiter

    2006-12-01

    Full Text Available O presente trabalho teve por objetivo a verificação de um procedimento matemático que permita a descrição do crescimento foliar de Kalanchoe (Kalanchoe blossfeldiana Poelln. e possa prever a sua área foliar fotossinteticamente ativa a partir de medidas não destrutivas de folhas. As mudas de Kalanchoe Cv. "Gold Jewel" foram cultivadas para o procedimento experimental em vasos irrigados com doses recomendadas para a cultura. Semanalmente, foram retirados três vasos da estufa e as plantas tiveram suas folhas cortadas, identificadas e submetidas a tomadas de medidas de sua posição na planta, do máximo comprimento longitudinal e do máximo comprimento transversal. Foram realizadas um total de nove coletas semanalmente, desde 04/04/2003 até o início da floração. Em cada coleta, três plantas eram amostradas e a área foliar calculada com a utilização do método de Gauss (GARCIA & PIEDADE, 1944 implementado em Visual Basic especificamente para este objetivo. Foram amostradas um total de 979 folhas e a verificação da possibilidade de uso de um fator de correção médio (FCM para o cálculo da área de uma folha, independentemente de sua posição na planta ou fase do ciclo de crescimento, foi averiguada por análise de regressão entre os valores obtidos pelo método padrão (Gauss e os valores estimados pelo método do FCM. Os resultados experimentais indicam que o valor FCM=1,1134 pode ser utilizado para estimar a área foliar pela multiplicação pelos valores de comprimento e largura de folha em qualquer fase do cultivo e sem qualquer posição da folha na planta.This research was aimed at versifying a mathematical procedure that allows the description of leaf of Kalanchoe (Kalanchoe blossfeldiana Poelln. and the estimation of its photosynthetically active leaf area starting from a non destructive leaf determination. Seedlings of Kalanchoe cv Gold Jewel were cultivated in irrigated vases with recommended doses for the culture

  2. Satellite Leaf Area Index: Global Scale Analysis of the Tendencies Per Vegetation Type Over the Last 17 Years

    Directory of Open Access Journals (Sweden)

    Simon Munier

    2018-03-01

    Full Text Available The main objective of this study is to detect and quantify changes in the vegetation dynamics of each vegetation type at the global scale over the last 17 years. With recent advances in remote sensing techniques, it is now possible to study the Leaf Area Index (LAI seasonal and interannual variability at the global scale and in a consistent way over the last decades. However, the coarse spatial resolution of these satellite-derived products does not permit distinguishing vegetation types within mixed pixels. Considering only the dominant type per pixel has two main drawbacks: the LAI of the dominant vegetation type is contaminated by spurious signal from other vegetation types and at the global scale, significant areas of individual vegetation types are neglected. In this study, we first developed a Kalman Filtering (KF approach to disaggregate the satellite-derived LAI from GEOV1 over nine main vegetation types, including grasslands and crops as well as evergreen, broadleaf and coniferous forests. The KF approach permits the separation of distinct LAI values for individual vegetation types that coexist within a pixel. The disaggregated LAI product, called LAI-MC (Multi-Cover, consists of world-wide LAI maps provided every 10 days for each vegetation type over the 1999–2015 period. A trend analysis of the original GEOV1 LAI product and of the disaggregated LAI time series was conducted using the Mann-Kendall test. Resulting trends of the GEOV1 LAI (which accounts for all vegetation types compare well with previous regional or global studies, showing a greening over a large part of the globe. When considering each vegetation type individually, the largest global trend from LAI-MC is found for coniferous forests (0.0419 m 2 m − 2 yr − 1 followed by summer crops (0.0394 m 2 m − 2 yr − 1 , while winter crops and grasslands show the smallest global trends (0.0261 m 2 m − 2 yr − 1 and 0.0279 m 2 m − 2 yr − 1 , respectively. The LAI

  3. Estimativa da área da folha da batateira utilizando medidas lineares Evaluation of the potato plant leaf area using linear measures

    Directory of Open Access Journals (Sweden)

    Marcelo CC Silva

    2008-03-01

    Full Text Available O objetivo deste experimento foi determinar o modelo mais apropriado para estimar a área da folha da batateira, utilizando-se medidas de comprimento e largura da folha. Foram coletadas 300 folhas de 300 plantas de batata, cultivar Monalisa, de forma aleatória, aos 21 e 56 dias após a emergência (DAE. Em laboratório, foram medidos o comprimento (C, a largura (L e a área de cada folha (AF. Os dados foram submetidos à análise de regressão com o valor da AF sendo considerado a variável dependente e os valores de comprimento e largura de folha as variáveis independentes. Foram testados três modelos estatísticos: linear, exponencial e logarítmico. A AF da batateira foi mais precisamente estimada (R² = 0,88, usando as medidas, L e C (AF = 0,2798**LC + 71,267. Para maior rapidez e praticidade, a AF da batateira, foi também apropriadamente estimada medindo-se apenas L ou C da folha e utilizando-se as equações AF = 0,0479**L + 10,777 (R² = 0,83 ou AF = 0,0659**C + 12,979 (R² = 0,82. A área foliar estimada 21 DAE, utilizando o modelo linear foi de 234,41 cm², sendo que o valor real medido, foi de 185,52 cm². Aos 56 DAE, a área foliar estimada pelo mesmo modelo foi de 175,60 cm², o valor real medido, foi de 176,01 cm². Com um dos modelos propostos, a área da folha pode ser estimada em tempo real, de forma rápida e sem a necessidade de coletar a folha.The objective of this experiment was to determine the most appropriate model to estimate potato leaf area through the leaf length and width. 300 leaves of 300 potato plants, cv. Monalisa were collected in an aleatory way, 21 and 56 days after the plant emergence (DAE. In laboratory, the length (C, width (L and area of each leaf (AF were measured. The data were submitted to the regression analysis with the AF value as a dependent variable and the leaf length and width values as the independent variables. Three statistical models were tested (linear, exponential and logarithmic. Potato

  4. Spatial distribution of tree species governs the spatio-temporal interaction of leaf area index and soil moisture across a forested landscape.

    Directory of Open Access Journals (Sweden)

    Kusum J Naithani

    Full Text Available Quantifying coupled spatio-temporal dynamics of phenology and hydrology and understanding underlying processes is a fundamental challenge in ecohydrology. While variation in phenology and factors influencing it have attracted the attention of ecologists for a long time, the influence of biodiversity on coupled dynamics of phenology and hydrology across a landscape is largely untested. We measured leaf area index (L and volumetric soil water content (θ on a co-located spatial grid to characterize forest phenology and hydrology across a forested catchment in central Pennsylvania during 2010. We used hierarchical Bayesian modeling to quantify spatio-temporal patterns of L and θ. Our results suggest that the spatial distribution of tree species across the landscape created unique spatio-temporal patterns of L, which created patterns of water demand reflected in variable soil moisture across space and time. We found a lag of about 11 days between increase in L and decline in θ. Vegetation and soil moisture become increasingly homogenized and coupled from leaf-onset to maturity but heterogeneous and uncoupled from leaf maturity to senescence. Our results provide insight into spatio-temporal coupling between biodiversity and soil hydrology that is useful to enhance ecohydrological modeling in humid temperate forests.

  5. A hybrid training approach for leaf area index estimation via Cubist and random forests machine-learning

    Science.gov (United States)

    Houborg, Rasmus; McCabe, Matthew F.

    2018-01-01

    With an increasing volume and dimensionality of Earth observation data, enhanced integration of machine-learning methodologies is needed to effectively analyze and utilize these information rich datasets. In machine-learning, a training dataset is required to establish explicit associations between a suite of explanatory 'predictor' variables and the target property. The specifics of this learning process can significantly influence model validity and portability, with a higher generalization level expected with an increasing number of observable conditions being reflected in the training dataset. Here we propose a hybrid training approach for leaf area index (LAI) estimation, which harnesses synergistic attributes of scattered in-situ measurements and systematically distributed physically based model inversion results to enhance the information content and spatial representativeness of the training data. To do this, a complimentary training dataset of independent LAI was derived from a regularized model inversion of RapidEye surface reflectances and subsequently used to guide the development of LAI regression models via Cubist and random forests (RF) decision tree methods. The application of the hybrid training approach to a broad set of Landsat 8 vegetation index (VI) predictor variables resulted in significantly improved LAI prediction accuracies and spatial consistencies, relative to results relying on in-situ measurements alone for model training. In comparing the prediction capacity and portability of the two machine-learning algorithms, a pair of relatively simple multi-variate regression models established by Cubist performed best, with an overall relative mean absolute deviation (rMAD) of ∼11%, determined based on a stringent scene-specific cross-validation approach. In comparison, the portability of RF regression models was less effective (i.e., an overall rMAD of ∼15%), which was attributed partly to model saturation at high LAI in association with

  6. A hybrid training approach for leaf area index estimation via Cubist and random forests machine-learning

    KAUST Repository

    McCabe, Matthew

    2017-12-06

    With an increasing volume and dimensionality of Earth observation data, enhanced integration of machine-learning methodologies is needed to effectively analyze and utilize these information rich datasets. In machine-learning, a training dataset is required to establish explicit associations between a suite of explanatory ‘predictor’ variables and the target property. The specifics of this learning process can significantly influence model validity and portability, with a higher generalization level expected with an increasing number of observable conditions being reflected in the training dataset. Here we propose a hybrid training approach for leaf area index (LAI) estimation, which harnesses synergistic attributes of scattered in-situ measurements and systematically distributed physically based model inversion results to enhance the information content and spatial representativeness of the training data. To do this, a complimentary training dataset of independent LAI was derived from a regularized model inversion of RapidEye surface reflectances and subsequently used to guide the development of LAI regression models via Cubist and random forests (RF) decision tree methods. The application of the hybrid training approach to a broad set of Landsat 8 vegetation index (VI) predictor variables resulted in significantly improved LAI prediction accuracies and spatial consistencies, relative to results relying on in-situ measurements alone for model training. In comparing the prediction capacity and portability of the two machine-learning algorithms, a pair of relatively simple multi-variate regression models established by Cubist performed best, with an overall relative mean absolute deviation (rMAD) of ∼11%, determined based on a stringent scene-specific cross-validation approach. In comparison, the portability of RF regression models was less effective (i.e., an overall rMAD of ∼15%), which was attributed partly to model saturation at high LAI in association

  7. 45 CFR 1321.41 - Single State planning and service area.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Single State planning and service area. 1321.41 Section 1321.41 Public Welfare Regulations Relating to Public Welfare (Continued) OFFICE OF HUMAN... PROGRAMS GRANTS TO STATE AND COMMUNITY PROGRAMS ON AGING State Agency Responsibilities § 1321.41 Single...

  8. A Comparison of Simulated and Field-Derived Leaf Area Index (LAI and Canopy Height Values from Four Forest Complexes in the Southeastern USA

    Directory of Open Access Journals (Sweden)

    John S. Iiames

    2018-01-01

    Full Text Available Vegetative leaf area is a critical input to models that simulate human and ecosystem exposure to atmospheric pollutants. Leaf area index (LAI can be measured in the field or numerically simulated, but all contain some inherent uncertainty that is passed to the exposure assessments that use them. LAI estimates for minimally managed or natural forest stands can be particularly difficult to develop as a result of interspecies competition, age and spatial distribution. Satellite-based LAI estimates hold promise for retrospective analyses, but we must continue to rely on numerical models for alternative management analysis. Our objective for this study is to calculate and validate LAI estimates generated from the USDA Environmental Policy Impact Climate (EPIC model (a widely used, field-scale, biogeochemical model on four forest complexes spanning three physiographic provinces in Virginia and North Carolina. Measurements of forest composition (species and number, LAI, tree diameter, basal area, and canopy height were recorded at each site during the 2002 field season. Calibrated EPIC results show stand-level temporally resolved LAI estimates with R2 values ranging from 0.69 to 0.96, and stand maximum height estimates within 20% of observation. This relatively high level of performance is attributable to EPIC’s approach to the characterization of forest stand biogeochemical budgets, stand history, interspecies competition and species-specific response to local weather conditions. We close by illustrating the extension of this site-level approach to scales that could support regional air quality model simulations.

  9. High genetic homogeneity points to a single introduction event responsible for invasion of Cotton leaf curl Multan virus and its associated betasatellite into China.

    Science.gov (United States)

    Du, Zhenguo; Tang, Yafei; He, Zifu; She, Xiaoman

    2015-10-07

    Cotton leaf curl Multan virus (CLCuMuV) is a Whitefly Transmitted Geminivirus (WTG) endemic to the India subcontinent and is notorious as a causal agent of cotton leaf curl disease (CLCuD), a major constraint to cotton production in south Asia. We found CLCuMuV infecting Hibiscus rosa-sinensis in Guangzhou, China in 2006. The spread and evolution of the invading CLCuMuV were monitored in the following nine years. CLCuMuV spread rapidly in the last nine years and became established in Southern China. It infects at least five malvaceous plant species, H. rosa-sinensis, H. esculentus, Malvaiscus arboreus, Gossypium hirsutum and H. cannabinus. Complete nucleotide sequences of 34 geographically and/or temporally distinct CLCuMuV isolates were determined and analyzed together with six other publicly available genomes of CLCuMuV occurring in China. The 40 CLCuMuV isolates were found to share > 99 % nucleotide sequence identity with each other. In all cases tested, the CLCuMuVs were associated with a CLCuMuB. The 36 CLCuMuBs (30 sequenced by us) shared > 98 % nucleotide sequence identity. The high genetic homogeneity of CLCuMuV and CLCuMuB in China suggests the establishment of them from a single founder event.

  10. Determination of Leaf Area Index, Total Foliar N, and Normalized Difference Vegetation Index for Arctic Ecosystems Dominated by Cassiope tetragona

    DEFF Research Database (Denmark)

    Campioli, M; Street, LE; Michelsen, Anders

    2009-01-01

    have not been accurately quantified. We address this knowledge gap by (i) direct measurements of LAI and TFN for C. tetragona, and (ii) determining TFN-LAI and LAI–normalized difference vegetation index (NDVI) relationships for typical C. tetragona tundras in the subarctic (Sweden) and High Arctic...... leaf N and biomass. The LAI-NDVI and TFN-LAI relationships showed high correlation and can be used to estimate indirectly LAI and TFN. The LAI-NDVI relationship for C. tetragona vegetation differed from a generic LAI-NDVI relationship for arctic tundra, whereas the TFN-LAI relationship did not. Overall...

  11. Vegetative propagation of Plukenetia polyadenia by cuttings: effects of leaf area and indole-3-butyric acid concentration

    OpenAIRE

    Solis, R.; Pezo, M.; Diaz, G.; Arévalo, L.; Cachique, D.

    2016-01-01

    Abstract The seeds of Plukenetia polyadenia have high levels of unsaturated fatty acids and are used as medicine and food for native people in the Peruvian and Brazilian Amazon. The objective of this study was to develop a method for vegetative propagation of Plukenetia polyadenia by rooting of cuttings. The experiment was laid out in a randomized complete block design with 12 treatments and 3 replications of 8 cuttings, in a 3 × 4 factorial arrangement. The factors were: 3 levels of leaf are...

  12. 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

    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...... albedo plus the weighted distance between the underlying vegetation canopy albedo and the albedo over deep snow. The LAI/FAPAR and surface albedo values estimated using this framework were compared with MODIS collection 5 eight-day 1-km LAI/FAPAR products (MOD15A2) and 500-m surface albedo product (MCD43......-series MODerate Resolution Imaging Spectroradiometer (MODIS) surface reflectance data. If the reflectance data showed snow-free areas, an ensemble Kalman filter (EnKF) technique was used to estimate leaf area index (LAI) for a two-layer canopy reflectance model (ACRM) by combining predictions from a phenology...

  13. Quantum dot resonant tunneling diode single photon detector with aluminum oxide aperture defined tunneling area

    DEFF Research Database (Denmark)

    Li, H.W.; Kardynal, Beata; Ellis, D.J.P.

    2008-01-01

    Quantum dot resonant tunneling diode single photon detector with independently defined absorption and sensing areas is demonstrated. The device, in which the tunneling is constricted to an aperture in an insulating layer in the emitter, shows electrical characteristics typical of high quality...... resonant tunneling diodes. A single photon detection efficiency of 2.1%+/- 0.1% at 685 nm was measured corresponding to an internal quantum efficiency of 14%. The devices are simple to fabricate, robust, and show promise for large absorption area single photon detectors based on quantum dot structures....

  14. 77 FR 59931 - Single Source Program Expansion Supplement Award to Area Health Education Centers (AHEC) Program...

    Science.gov (United States)

    2012-10-01

    ... grantee, to coordinate the U.S. Affiliated Pacific Islands (USAPI) Nursing Program Capacity Strengthening... Program Expansion Supplement Award to Area Health Education Centers (AHEC) Program Grantee; Exception to... Competition--Single Source Program Expansion Supplement Award to Area Health Education Centers (AHEC) Program...

  15. Área foliar e número de flores de nastúrcio sob duas densidades de plantio Leaf area and flower number of nasturtium in two plant densities

    Directory of Open Access Journals (Sweden)

    Sidinei José Lopes

    2007-06-01

    Full Text Available Estimou-se a área foliar do nastúrcio (Tropaeolum majus L. por métodos não destrutivos e determinou-se a variação temporal da área foliar e do número de flores sob duas densidades de plantas em dois experimentos, em estufa plástica, na UFSM. No primeiro experimento calculou-se a área foliar a partir da análise de 50 folhas, provenientes de dez plantas, através de imagens digitais, relacionando-a à estimativa da área foliar feita a partir de discos foliares. Correlacionou-se também a área foliar à medida de quatro diagonais das folhas: medida sobre a nervura principal, perpendicular à nervura principal e duas medidas transversais à nervura principal. Obteve-se coeficiente de determinação (r² de 0,94 (p Two experiments were conducted in a plastic greenhouses in Santa Maria, Rio Grande do Sul State, Brazil, to estimate the nasturtium (Tropaeolum majus L. leaf area through non destructive methods, as well as to study the leaf area and flower number variation in time, in two planting densities. In the first experiment, leaf area was assessed using 50 leaves harvested out of ten plants through digital image. This calculated value was then compared to leaf area estimation obtained using leaf disks. In addition, leaf area was correlated to the following leaf diagonals: main rib, perpendicular to the main rib, and two transversal measures to the main rib. A determination coefficient (r² of 0,94 (p<0,05 was obtained for leaf area calculated through digital images and leaf disks. The leaf area formula 0,8906x², where x corresponds to the measure on the main rib, presented the largest determination coefficient (r² = 0,99; p<0,05 among the four tested diagonals. In the second experiment, two plant densities were tested: 0.60 x 0.50 m and 0.30 x 0.25 respectively between plants and rows. For each plant density, leaf area was estimated using the equation adjusted for the length of the main rib. Main rib was measured in all leaves

  16. High NDVI and Potential Canopy Photosynthesis of South American Subtropical Forests despite Seasonal Changes in Leaf Area Index and Air Temperature

    Directory of Open Access Journals (Sweden)

    Piedad M. Cristiano

    2014-02-01

    Full Text Available The canopy photosynthesis and carbon balance of the subtropical forests are not well studied compared to temperate and tropical forest ecosystems. The main objective of this study was to assess the seasonal dynamics of Normalized Difference Vegetation Index (NDVI and potential canopy photosynthesis in relation to seasonal changes in leaf area index (LAI, chlorophyll concentration, and air temperatures of NE Argentina subtropical forests throughout the year. We included in the analysis several tree plantations (Pinus, Eucalyptus and Araucaria species that are known to have high productivity. Field studies in native forests and tree plantations were conducted; stem growth rates, LAI and leaf chlorophyll concentration were measured. MODIS satellite-derived LAI (1 km SIN Grid and NDVI (250m SIN Grid from February 2000 to 2012 were used as a proxy of seasonal dynamics of potential photosynthetic activity at the stand level. The remote sensing LAI of the subtropical forests decreased every year from 6 to 5 during the cold season, similar to field LAI measurements, when temperatures were 10 °C lower than during the summer. The yearly maximum NDVI values were observed during a few months in autumn and spring (March through May and November, respectively because high and low air temperatures may have a small detrimental effect on photosynthetic activity during both the warm and the cold seasons. Leaf chlorophyll concentration was higher during the cold season than the warm season which may have a compensatory effect on the seasonal variation of the NDVI values. The NDVI of the subtropical forest stands remained high and fairly constant throughout the year (the intra-annual coefficient of variation was 1.9%, and were comparable to the values of high-yield tree plantations. These results suggest that the humid subtropical forests in NE Argentina potentially could maintain high canopy photosynthetic activity throughout the year and thus this ecosystem may

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

    Science.gov (United States)

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

    2013-12-01

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

  18. Single pot synthesized gold nanoparticles using Hippophae rhamnoides leaf and berry extract showed shape-dependent differential nanobiotechnological applications.

    Science.gov (United States)

    Sharma, Bhavana; Deswal, Renu

    2018-04-04

    A facile one-pot green synthesis of gold nanoparticles (AuNPs) with different geometries was achieved using an underutilized Himalayan bioresource Hippophae rhamnoides. Aqueous leaf (LE) and berry extracts (BE) showed rapid synthesis of monodispersed spherical LEAuNPs (27 ± 3.2 nm) and anisotropic BEAuNPs (55 ± 4.5 nm) within 2 and 15 min, respectively. The Fourier-transform infrared (FTIR) spectroscopy showed involvement of polyphenolics/flavonoids in AuNPs reduction. LE AuNPs (IC 50 49 µg) exhibited higher antioxidant potential than BE AuNPs (IC 50 57 µg). Both BE nanotriangles and LE nanospheres exhibited cytotoxicity against Jurkat cell lines. These nanocatalysts also exhibited effective (80-99%) reductive degradation of structurally different carcinogenic azo dyes. Kinetic studies revealed that BE nanotriangles exhibited higher catalytic efficiency (14-67%) than LE nanospheres suggesting shape-dependent regulation of biological activities. The gas chromatography-mass spectrometry (GC-MS) analysis confirmed conversion of toxic methyl orange dye to non-toxic intermediates. Probable degradation mechanism involving adsorption and catalytic reduction of azo bonds was proposed. The present synthesis protocol provided a facile and energy saving procedure for rapid synthesis of highly stable nanoparticles with significant antioxidant and anticancer potential. This is the first report of H. rhamnoides-mediated green synthesis of multipurpose AuNPs as antioxidant, anticancer and nanocatalytic agents for treatment of dye contaminated waste water and future therapeutic applications.

  19. Land cover in single-family housing areas and how it correlates with urban form

    DEFF Research Database (Denmark)

    Nielsen, Mette Boye; Jensen, Marina Bergen

    2015-01-01

    Land cover composition is a valuable indicator of the ecological performance of a city. Single-family housing areas constitute a substantial part of most cities and may as such play an important role for sustainable urban development. From aerial photos we performed detailed GIS-based mapping...... that the urban form of neighbourhoods to some degree predicts the long term land cover composition. We conclude that strategies for maximizing the ecological performance of single-family housing areas can be informed by knowledge on urban form, and that digital mapping of land cover based on aerial photography...... of land cover in three detached single-family housing areas in Denmark of different urban form but comparable housing densities (ranging from 10.0 to 11.3 houses per hectare). The findings were subjected to statistical analysis and landscape metrics. Land cover varied with urban form: A traditional...

  20. Genetic control and combining ability of flag leaf area and relative water content traits of bread wheat cultivars under drought stress condition

    Directory of Open Access Journals (Sweden)

    Golparvar Ahmad Reza

    2013-01-01

    Full Text Available In order to compare mode of inheritance, combining ability, heterosis and gene action in genetic control of traits flag leaf area, relative water content and grain filling rate of bread wheat under drought stress, a study was conducted on 8 cultivars using of Griffing’s method2 in fixed model. Mean square of general combining ability was significant also for all traits and mean square of specific combining ability was significant also for all traits except relative water content of leaf which show importance of both additive and dominant effects of genes in heredity of these traits under stress. GCA to SCA mean square ratio was significant for none of traits. Results of this study showed that non additive effects of genes were more important than additive effect for all traits. According to results we can understand that genetic improvement of mentioned traits will have low genetic efficiency by selection from the best crosses of early generations. Then it is better to delay selection until advanced generations and increase in heritability of these traits.

  1. Evaluation of Indirect Measurement Method of Seasonal Patterns of Leaf Area Index in a High-Density Short Rotation Coppice Culture of Poplar

    Directory of Open Access Journals (Sweden)

    Abhishek M. Tripathi

    2016-01-01

    Full Text Available Leaf area index (LAI is an important determinant of biomass production and yield of short rotation bio-energy plantation. An accurate measurement of LAI is critical for quantifying light interception and penetration within the canopy, and subsequently understanding its influence on the stand carbon and energy balance. The aim of the current study is validation of the Sunscan Plant Canopy Analyzer which serves as an indirect method for the evaluation of the seasonal patterns of LAI, relation between LAI and above ground woody dry biomass and to determine the specific leaf area in short-rotation poplar hybrid clone J-105 (Populus nigra × P. maximowiczii in uncoppiced (1st rotation and coppiced (2nd rotation, respectively. LAI was measured in uncoppiced and coppiced by two different methods using indirect (SunScan Plant Canopy Analyzer and direct (litterfall collection. Sunscan Plant Canopy Analyzer was compared against litterfall collection (only way to retrieve the actual LAI. Simple regression (R2 = 0.82 model was fitted to validate indirect measurement method and a very good agreement (82% was observed in LAI values estimated from SunScan Plant Canopy Analyzer and from litterfall collection. Seasonal variability of LAI in a short rotation coppice (SRC culture of poplar clone J-105 was evaluated over six years period (2008–2013, for uncoppiced (2008 and 2009 and coppiced (2010, 2011, 2012 and 2013 culture. The maximum canopy LAI (LAImax reached 7.3 (uncoppiced and 9.5 (coppiced. The linear regression (R2 = 0.93 for average LAI and above ground woody dry biomass was determined, and it was found that LAI acts an indicator of biomass productivity. Specific leaf area (SLA was estimated in both uncoppiced and coppiced culture of poplar. The maximum SLA was found to be 138.9 cm2g−1 in uncoppiced and 126.9 cm2g−1 in coppiced. To conclude, the evaluated indirect LAI measurement method is portable, reliable and faster than direct LAI measurement

  2. Modeling canopy-level productivity: is the "big-leaf" simplification acceptable?

    Science.gov (United States)

    Sprintsin, M.; Chen, J. M.

    2009-05-01

    The "big-leaf" approach to calculating the carbon balance of plant canopies assumes that canopy carbon fluxes have the same relative responses to the environment as any single unshaded leaf in the upper canopy. Widely used light use efficiency models are essentially simplified versions of the big-leaf model. Despite its wide acceptance, subsequent developments in the modeling of leaf photosynthesis and measurements of canopy physiology have brought into question the assumptions behind this approach showing that big leaf approximation is inadequate for simulating canopy photosynthesis because of the additional leaf internal control on carbon assimilation and because of the non-linear response of photosynthesis on leaf nitrogen and absorbed light, and changes in leaf microenvironment with canopy depth. To avoid this problem a sunlit/shaded leaf separation approach, within which the vegetation is treated as two big leaves under different illumination conditions, is gradually replacing the "big-leaf" strategy, for applications at local and regional scales. Such separation is now widely accepted as a more accurate and physiologically based approach for modeling canopy photosynthesis. Here we compare both strategies for Gross Primary Production (GPP) modeling using the Boreal Ecosystem Productivity Simulator (BEPS) at local (tower footprint) scale for different land cover types spread over North America: two broadleaf forests (Harvard, Massachusetts and Missouri Ozark, Missouri); two coniferous forests (Howland, Maine and Old Black Spruce, Saskatchewan); Lost Creek shrubland site (Wisconsin) and Mer Bleue petland (Ontario). BEPS calculates carbon fixation by scaling Farquhar's leaf biochemical model up to canopy level with stomatal conductance estimated by a modified version of the Ball-Woodrow-Berry model. The "big-leaf" approach was parameterized using derived leaf level parameters scaled up to canopy level by means of Leaf Area Index. The influence of sunlit

  3. Área foliar de duas trepadeiras infestantes de cana-de-açúcar utilizando dimensões lineares de folhas Foliar area estimate of two sugarcane-infesting weeds using leaf blade linear dimensions

    Directory of Open Access Journals (Sweden)

    N.P. Cardozo

    2009-01-01

    Full Text Available Esta pesquisa teve como objetivo obter uma equação, por meio de medidas lineares dimensionais das folhas, que permitisse a estimativa da área foliar de Momordica charantia e Pyrostegia venusta. Entre maio e dezembro de 2007, foram estudadas as correlações entre a área folia real (Sf e as medidas dimensionais do limbo foliar, como o comprimento ao longo da nervura principal (C e a largura máxima (L perpendicular à nervura principal. Todas as equações, exponenciais geométricas ou lineares simples, permitiram boas estimativas da área foliar. Do ponto de vista prático, sugere-se optar pela equação linear simples envolvendo o produto C x L, considerando-se o coeficiente linear igual a zero. Desse modo, a estimativa da área foliar de Momordica charantia pode ser feita pela fórmula Sf = 0,4963 x (C x L, e a de Pyrostegia venusta, por Sf = 0,6649 x (C x L.The aim of this study was to obtain a mathematical equation to estimate the leaf area of Momordica charantia and Pyrostegia venusta using linear leaf blade measurements. Correlation studies were conducted involving real leaf area (Sf and leaf length (C, maximum leaf width (L and C x L. The linear and geometric equations involving parameter C provided good leaf area estimates. From a practical viewpoint, the simple linear equation of the regression model is suggested using the C x L parameter, i.e., considering the linear coefficient equal to zero. Thus, leaf area estimate of Momordica charantia can be obtained by using the equation Sf = 0.4963 x (C x L, and that of Pyrostegia venusta by using equation Sf = 0.6649 x (C x L.

  4. A model of canopy irradiance in relation to changing leaf area in a phytotron-grown snap bean ( Phaseolus vulgaris L.) Crop

    Science.gov (United States)

    Lieth, J. H.; Reynolds, J. F.

    1984-03-01

    Simple exponential decay models were used to describe the variation in irradiance profiles within a snap bean ( Phaseolus vulgaris L.) canopy over a 33-day period of canopy development. The extinction coefficients of these models were varied over time as a function of changing canopy leaf area; nonlinear least-squares procedures were used to estimate parameter values. The resultant model response surfaces depict the changes in canopy irradiance that accompany canopy maturation and illustrate the dynamic nature of canopy closure. A criterion index is defined to aid in assessing the applicability of these models for use in whole-plant simulation models, and an evaluation of these models is given based on this index, their predictive accuracy, and the utility for use within varying modeling frameworks.

  5. Effect of Salinity Stress and Iron Spraying on Leaf Area Index, Light Absorption and Relations with Yield in Sunflower (Helianthus annuns L.

    Directory of Open Access Journals (Sweden)

    M.H Shariatmadari

    2012-02-01

    Full Text Available Salinity stress results to decreasing leaf area index (LAI and light absorption in plant leading in yield decrease. In order to study effect of salinity and iron sulphate on LAI, absorbed light percentage and yield of sunflower (Euroflor cultivar, an experiment was carried out as split plot based on complete randomized block design with four replications in the Research Field of University of Birjand on 2009. In this experiment main plots were different levels of irrigation with saline water and subplot was levels of Iron Sulphate. Results showed that with decreased LAI and light absorption, yield was negatively responded to salinity. One way for recovery of light absorption in salinity condition is spraying iron sulphate. The Highest light absorption percentage up to 70.34% was obtained in control condition with the LAI of 3. In this condition yield of sunflower was 4250 kg/ha. Iron sulphate spraying reduced the negative effects of salinity on LAI.

  6. A new control scheme for PID load frequency controller of single-area and multi-area power systems.

    Science.gov (United States)

    Padhan, Dola Gobinda; Majhi, Somanath

    2013-03-01

    A new control structure with a tuning method to design a PID load frequency controller for power systems is presented. Initially, the controller is designed for single area power system, then it is extended to multi-area case. The controller parameters are obtained by expanding controller transfer function using Laurent series. Relay based identification technique is adopted to estimate power system dynamics. Robustness studies on stability and performance are provided, with respect to uncertainties in the plant parameters. The proposed scheme ensures that overall system remains asymptotically stable for all bounded uncertainties and for system oscillations. Simulation results show the feasibility of the approach and the proposed method improves the load disturbance rejection performance significantly even in the presence of the uncertainties in plant parameters. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

  7. Application of Economic MPC to Frequency Control in a Single-Area

    DEFF Research Database (Denmark)

    Sokoler, Leo Emil; Edlund, Kristian; Jørgensen, John Bagterp

    2016-01-01

    This paper presents a novel model predictive control scheme for frequency control in a single-area power system. The proposed controller provides set-point corrections to the system power generators, based on the solution to an optimal control problem. The optimal control problem directly incorpo...

  8. Geology Data Package for the Single-Shell Tank Waste Management Areas at the Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Reidel, Steve P.; Chamness, Mickie A.

    2007-01-01

    This data package discusses the geology of the single-shell tank (SST) farms and the geologic history of the area. The focus of this report is to provide the most recent geologic information available for the SST farms. This report builds upon previous reports on the tank farm geology and Integrated Disposal Facility geology with information available after those reports were published.

  9. Leaf area index drives soil water availability and extreme drought-related mortality under elevated CO2 in a temperate grassland model system.

    Science.gov (United States)

    Manea, Anthony; Leishman, Michelle R

    2014-01-01

    The magnitude and frequency of climatic extremes, such as drought, are predicted to increase under future climate change conditions. However, little is known about how other factors such as CO2 concentration will modify plant community responses to these extreme climatic events, even though such modifications are highly likely. We asked whether the response of grasslands to repeat extreme drought events is modified by elevated CO2, and if so, what are the underlying mechanisms? We grew grassland mesocosms consisting of 10 co-occurring grass species common to the Cumberland Plain Woodland of western Sydney under ambient and elevated CO2 and subjected them to repeated extreme drought treatments. The 10 species included a mix of C3, C4, native and exotic species. We hypothesized that a reduction in the stomatal conductance of the grasses under elevated CO2 would be offset by increases in the leaf area index thus the retention of soil water and the consequent vulnerability of the grasses to extreme drought would not differ between the CO2 treatments. Our results did not support this hypothesis: soil water content was significantly lower in the mesocosms grown under elevated CO2 and extreme drought-related mortality of the grasses was greater. The C4 and native grasses had significantly higher leaf area index under elevated CO2 levels. This offset the reduction in the stomatal conductance of the exotic grasses as well as increased rainfall interception, resulting in reduced soil water content in the elevated CO2 mesocosms. Our results suggest that projected increases in net primary productivity globally of grasslands in a high CO2 world may be limited by reduced soil water availability in the future.

  10. Leaf area index drives soil water availability and extreme drought-related mortality under elevated CO2 in a temperate grassland model system.

    Directory of Open Access Journals (Sweden)

    Anthony Manea

    Full Text Available The magnitude and frequency of climatic extremes, such as drought, are predicted to increase under future climate change conditions. However, little is known about how other factors such as CO2 concentration will modify plant community responses to these extreme climatic events, even though such modifications are highly likely. We asked whether the response of grasslands to repeat extreme drought events is modified by elevated CO2, and if so, what are the underlying mechanisms? We grew grassland mesocosms consisting of 10 co-occurring grass species common to the Cumberland Plain Woodland of western Sydney under ambient and elevated CO2 and subjected them to repeated extreme drought treatments. The 10 species included a mix of C3, C4, native and exotic species. We hypothesized that a reduction in the stomatal conductance of the grasses under elevated CO2 would be offset by increases in the leaf area index thus the retention of soil water and the consequent vulnerability of the grasses to extreme drought would not differ between the CO2 treatments. Our results did not support this hypothesis: soil water content was significantly lower in the mesocosms grown under elevated CO2 and extreme drought-related mortality of the grasses was greater. The C4 and native grasses had significantly higher leaf area index under elevated CO2 levels. This offset the reduction in the stomatal conductance of the exotic grasses as well as increased rainfall interception, resulting in reduced soil water content in the elevated CO2 mesocosms. Our results suggest that projected increases in net primary productivity globally of grasslands in a high CO2 world may be limited by reduced soil water availability in the future.

  11. Multivariate assimilation of coarse scale soil moisture, cosmic-ray soil moisture, land surface temperature and leaf area index in CLM4.5

    Science.gov (United States)

    Han, Xujun; Hendricks Franssen, Harrie-Jan; Schalge, Bernd; Baroni, Gabriele; Rihani, Jehan; Kollet, Stefan; Vereecken, Harry; Simmer, Clemens

    2017-04-01

    The land surface plays a central role in the atmosphere - land surface - subsurface continuum. Surface soil moisture for instance impacts the partitioning of absorbed radiation in heating ground and atmosphere and thus impacts resulting evapotranspiration. The land surface also drives partitioning of rainfall between infiltration which ends up as groundwater recharge and surface runoff contributing to stream discharge. It is therefore expected that the use of observations for characterizing and predicting the land surface state also leads to improved state estimations and predictions in all the other sub-compartments of the system we consider: groundwater, stream discharge and atmosphere. To test this hypothesis requires efficient data assimilation schemes that are capable to take up specific requirements of different compartments, such as different time windows of observations. In this study we will derive such data assimilation methods and quantify the improvement of predictions in the different compartments due to assimilation of multiple observations, and evaluate to what extent assimilation of land surface observations will also improve predictions of land surface states and fluxes for atmosphere and groundwater. We argue that improvements can be achieved by implementing a data assimilation methodology that is capable of simultaneous assimilation of many data sources (remote sensing soil moisture, cosmic-ray measurement for soil moisture, land surface temperature and leaf area index) at different spatial scales ranging from 102 m to 104 m. The multivariate data assimilation system for the land-surface component will be developed and extended to assimilate the coarse scale remote sensing soil moisture, cosmic-ray soil moisture, land surface temperature and leaf area index, and their different combinations using the local ensemble transform Kalman filter. The multivariate data assimilation will be evaluated using a synthetic study which mimics the Neckar

  12. Large Mode Area Single Trench Fiber for 2 mu m Operation

    DEFF Research Database (Denmark)

    Jain, Deepak; Sahu, Jayanta K.

    2016-01-01

    to 25 cm bend radius, respectively, by exploiting high delocalization of the higher order modes. Achievement of a large effective-area can be very useful to address nonlinear effects. Moreover, single trench fiber offers certain advantages such as low-cost fabrication and easy postprocessing (such......Performance of single trench fibers has been investigated using finite-element method at 2 mu m wavelength. Numerical investigations show that an effective single mode operation for large effective area between 3000-4000 mu m(2) and 2000-3000 mu m(2) can be achieved at similar to 40 and similar...... as cleaving and splicing) thanks to the all-solid fiber design....

  13. SU-F-T-629: Effect of Multi-Leaf Collimator (MLC) Width On Plan Quality of Single-Isocenter VMAT Intracranial Stereotactic Radiosurgery for Multiple Metastases

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, J; Thomas, E; Wu, X; Fiveash, J; Popple, R [University Alabama Birmingham, Birmingham, AL (United States)

    2016-06-15

    Purpose: Single-isocenter VMAT has been shown able to create high quality plans for complex intracranial multiple metastasis SRS cases. Linacs capable of the technique are typically outfitted with an MLC that consists of a combination of 5 mm and 10 mm leaves (standard) or 2.5 mm and 5 mm leaves (high-definition). In this study, we test the hypothesis that thinner collimator leaves are associated with improved plan quality. Methods: Ten multiple metastasis cases were identified and planned for VMAT SRS using a 10 MV flattening filter free beam. Plans were created for a standard (std) and a high-definition (HD) MLC. Published values for leaf transmission factor and dosimetric leaf gap were utilized. All other parameters were invariant. Conformity (plan and individual target), moderate isodose spill (V50%), and low isodose spill (mean brain dose) were selected for analysis. Results: Compared to standard MLC, HD-MLC improved overall plan conformity (median: Paddick CI-HD = 0.83, Paddick CI-std = 0.79; p = 0.004 and median: RTOG CI-HD =1.18, RTOG CI-std =1.24; p = 0.01 ), improved individual lesion conformity (median: Paddick CI-HD,i =0.77, Paddick CI-std,i =0.72; p < 0.001 and median: RTOG CI-HD,i = 1.28, RTOG CI-std,i =1.35; p < 0.001), improved moderate isodose spill (median: V50%-HD = 37.0 cc, V50%-std = 45.7 cc; p = 0.002), and improved low dose spill (median: dmean-HD = 2.90 Gy, dmean-std = 3.19 Gy; p = 0.002). Conclusion: For the single-isocenter VMAT SRS of multiple metastasis plans examined, use of HD-MLC modestly improved conformity, moderate isodose, and low isodose spill compared to standard MLC. However, in all cases we were able to generate clinically acceptable plans with the standard MLC. More work is need to further quantify the difference in cases with higher numbers of small targets and to better understand any potential clinical significance. This research was supported in part by Varian Medical Systems.

  14. SU-F-T-629: Effect of Multi-Leaf Collimator (MLC) Width On Plan Quality of Single-Isocenter VMAT Intracranial Stereotactic Radiosurgery for Multiple Metastases

    International Nuclear Information System (INIS)

    Kraus, J; Thomas, E; Wu, X; Fiveash, J; Popple, R

    2016-01-01

    Purpose: Single-isocenter VMAT has been shown able to create high quality plans for complex intracranial multiple metastasis SRS cases. Linacs capable of the technique are typically outfitted with an MLC that consists of a combination of 5 mm and 10 mm leaves (standard) or 2.5 mm and 5 mm leaves (high-definition). In this study, we test the hypothesis that thinner collimator leaves are associated with improved plan quality. Methods: Ten multiple metastasis cases were identified and planned for VMAT SRS using a 10 MV flattening filter free beam. Plans were created for a standard (std) and a high-definition (HD) MLC. Published values for leaf transmission factor and dosimetric leaf gap were utilized. All other parameters were invariant. Conformity (plan and individual target), moderate isodose spill (V50%), and low isodose spill (mean brain dose) were selected for analysis. Results: Compared to standard MLC, HD-MLC improved overall plan conformity (median: Paddick CI_HD = 0.83, Paddick CI_std = 0.79; p = 0.004 and median: RTOG CI_HD =1.18, RTOG CI_std =1.24; p = 0.01 ), improved individual lesion conformity (median: Paddick CI_HD,i =0.77, Paddick CI_std,i =0.72; p < 0.001 and median: RTOG CI_HD,i = 1.28, RTOG CI_std,i =1.35; p < 0.001), improved moderate isodose spill (median: V50%_HD = 37.0 cc, V50%_std = 45.7 cc; p = 0.002), and improved low dose spill (median: dmean_HD = 2.90 Gy, dmean_std = 3.19 Gy; p = 0.002). Conclusion: For the single-isocenter VMAT SRS of multiple metastasis plans examined, use of HD-MLC modestly improved conformity, moderate isodose, and low isodose spill compared to standard MLC. However, in all cases we were able to generate clinically acceptable plans with the standard MLC. More work is need to further quantify the difference in cases with higher numbers of small targets and to better understand any potential clinical significance. This research was supported in part by Varian Medical Systems.

  15. Effects of Nitrogen Addition on Leaf Decomposition of Single-Species and Litter Mixture in Pinus tabulaeformis Forests

    Directory of Open Access Journals (Sweden)

    Jinsong Wang

    2015-12-01

    Full Text Available The litter decomposition process is closely correlated with nutrient cycling and the maintenance of soil fertility in the forest ecosystem. In particular, the intense environmental concern about atmospheric nitrogen (N deposition requires a better understanding of its influence on the litter decomposition process. This study examines the responses of single-species litter and litter mixture decomposition processes to N addition in Chinese pine (Pinus tabulaeformis Carr. ecosystems. Chinese pine litter, Mongolian oak (Quercus mongolica Fisch. ex Ledeb. litter, and a pine–oak mixture were selected from a plantation and a natural forest of Chinese pine. Four N addition treatments, i.e., control (N0: 0 kg N ha−1·year−1, low-N (N1: 5 kg N ha−1·year−1, medium-N (N2: 10 kg N ha−1·year−1, and high-N (N3: 15 kg N ha−1·year−1, were applied starting May 2010. In the plantation, N addition significantly stimulated the decomposition of the Chinese pine litter. In the natural forest, N addition had variable effects on the decomposition of single-species litter and the litter mixture. A stimulatory effect of the high-N treatment on the Chinese pine litter decomposition could be attributed to a decrease in the substrate C:N ratio. However, an opposite effect was found for the Mongolian oak litter decomposition. The stimulating effect of N addition on the Chinese pine litter may offset the suppressive effect on the Mongolian oak litter, resulting in a neutral effect on the litter mixture. These results suggest that the different responses in decomposition of single-species litter and the litter mixture to N addition are mainly attributed to litter chemical composition. Further investigations are required to characterize the effect of long-term high-level N addition on the litter decomposition as N deposition is likely to increase rapidly in the region where this study was conducted.

  16. Habitat Complexity of Stream Leaf Packs: Effects on Benthic Macroinvertebrates and Leaf Litter Breakdown

    Science.gov (United States)

    Ruetz, C. R.; Vanhaitsma, D. L.; Breen, M. J.

    2005-05-01

    We investigated two attributes of leaf-pack complexity (i.e., leaf-pack mass and leaf surface area) on fish predation, colonization of benthic macroinvertebrates, and leaf breakdown rates in a coldwater Michigan stream. We manipulated three factors using a factorial design: fish (exclusion or control cage), leaf-pack mass (1, 3, or 5 g dry mass), and leaf surface area (10 cm leaf width). Acer leaves were fastened into leaf packs. Exclusion cages had mesh on all sides; control cages lacked mesh on two sides to provide access to fishes. Two replicate leaf packs were randomly collected after 25-31 d from two sections of the stream (n = 4). Common shredders were Gammarus, Pycnopsyche, and Lepidostoma. We did not detect a significant effect of fish predation on benthic macroinvertebrates or leaf breakdown (i.e., mass loss). Colonization of benthic macroinvertebrates appeared proportional to leaf-pack mass but was unaffected by the surface area of leaves. Leaf breakdown was more rapid among leaf packs with fewer leaves (i.e., leaves with large surface area and leaf packs with low mass) and greater numbers of shredders. We suspect that physical fragmentation is the primary mechanism for higher breakdown rates among leaf packs with fewer leaves.

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

    Science.gov (United States)

    Ding, Risheng; Kang, Shaozhong; Du, Taisheng; Hao, Xinmei; Zhang, Yanqun

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Risheng Ding

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

  19. Search of Xylella fastidiosa in plants with symptoms of chlorosis and leaf scorch present in ornamental areas in the university district and nearness

    International Nuclear Information System (INIS)

    Pacheco Acevedo, Maria Jose

    2010-01-01

    The presence of Xylella fastidiosa is detected in plants considered as hosts of urban ornament with characteristic symptoms, present in gardens in the area of the university district and around in the area. Urban ornamental plants are identified with suggestive symptomatology of infection by X. fastidiosa in gardens of urban areas. Plants are classified according to the presence or absence of symptoms. In the study were gathered 97 samples, belonging to 29 vegetable species with symptoms of chlorosis on leaves, leaf scorch, delay in the development and loss of foliage. The identified plants are screened by techniques of ELISA, and immunofluorescence for the detection of X. fastidiosa. Xylella fastidiosa is isolated from urban ornamental plants. The isolates of Xylella obtained, are characterized phenotypic and molecularly. The performance of two standardized immunological techniques are compared for the serological detection of Xylella fastidiosa. The presence of X. fastidiosa is detected, using the DAS-ELISA technique on 48 of the 97 processed samples, corresponding to 46,1% of the samples. Parallely, the samples processed using the IFA technique, have detected the presence of X. fastidiosa in the same proportions [es

  20. SSR markers associated to early leaf spot disease resistance through selective genotyping and single marker analysis in groundnut (Arachis hypogaea L.

    Directory of Open Access Journals (Sweden)

    Adama Zongo

    2017-09-01

    Full Text Available Groundnut (Arachis hypogaea L. is an important oilseed and food crop of the world. Breeding for disease resistance is one of major objectives in groundnut breeding. Early leaf spot (ELS is one of the major destructive diseases worldwide and in West Africa, particularly in Burkina Faso causing significant yield losses. Conventional breeding approaches have been employed to develop improved varieties resistant to ELS. Molecular dissection of resistance traits using QTL analysis can improve the efficiency of resistance breeding. In the present study, an ELS susceptible genotype QH243C and an ELS resistant genotype NAMA were crossed and the F2 population genotypic and F3 progenies phenotypic data were used for marker-trait association analysis. Parents were surveyed with 179 simple sequence repeat (SSR markers out of which 103 SSR markers were found to be polymorphic between the parents. These polymorphic markers were utilized to genotype the F2 population followed by marker-trait analysis through single marker analysis (SMA and selective genotyping of the population using 23 resistant and 23 susceptible genotypes. The SMA revealed 13 markers while the selective genotyping method identified 8 markers associated with ELS resistance. Four markers (GM1911, GM1883, GM1000 and Seq13E09 were found common between the two trait mapping methods. These four markers could be employed in genomics-assisted breeding for selection of ELS resistant genotypes in groundnut breeding.

  1. Leaf aging of Amazonian canopy trees as revealed by spectral and physiochemical measurements.

    Science.gov (United States)

    Chavana-Bryant, Cecilia; Malhi, Yadvinder; Wu, Jin; Asner, Gregory P; Anastasiou, Athanasios; Enquist, Brian J; Cosio Caravasi, Eric G; Doughty, Christopher E; Saleska, Scott R; Martin, Roberta E; Gerard, France F

    2017-05-01

    Leaf aging is a fundamental driver of changes in leaf traits, thereby regulating ecosystem processes and remotely sensed canopy dynamics. We explore leaf reflectance as a tool to monitor leaf age and develop a spectra-based partial least squares regression (PLSR) model to predict age using data from a phenological study of 1099 leaves from 12 lowland Amazonian canopy trees in southern Peru. Results demonstrated monotonic decreases in leaf water (LWC) and phosphorus (P mass ) contents and an increase in leaf mass per unit area (LMA) with age across trees; leaf nitrogen (N mass ) and carbon (C mass ) contents showed monotonic but tree-specific age responses. We observed large age-related variation in leaf spectra across trees. A spectra-based model was more accurate in predicting leaf age (R 2  = 0.86; percent root mean square error (%RMSE) = 33) compared with trait-based models using single (R 2  = 0.07-0.73; %RMSE = 7-38) and multiple (R 2  = 0.76; %RMSE = 28) predictors. Spectra- and trait-based models established a physiochemical basis for the spectral age model. Vegetation indices (VIs) including the normalized difference vegetation index (NDVI), enhanced vegetation index 2 (EVI2), normalized difference water index (NDWI) and photosynthetic reflectance index (PRI) were all age-dependent. This study highlights the importance of leaf age as a mediator of leaf traits, provides evidence of age-related leaf reflectance changes that have important impacts on VIs used to monitor canopy dynamics and productivity and proposes a new approach to predicting and monitoring leaf age with important implications for remote sensing. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  2. Reflectance of Biological Turbid Tissues under Wide Area Illumination: Single Backward Scattering Approach

    Directory of Open Access Journals (Sweden)

    Guennadi Saiko

    2014-01-01

    Full Text Available Various scenarios of light propagation paths in turbid media (single backward scattering, multiple backward scattering, banana shape are discussed and their contributions to reflectance spectra are estimated. It has been found that a single backward or multiple forward scattering quasi-1D paths can be the major contributors to reflected spectra in wide area illumination scenario. Such a single backward scattering (SBS approximation allows developing of an analytical approach which can take into account refractive index mismatched boundary conditions and multilayer geometry and can be used for real-time spectral processing. The SBS approach can be potentially applied for the distances between the transport and reduced scattering domains. Its validation versus the Kubelka-Munk model, path integrals, and diffusion approximation of the radiation transport theory is discussed.

  3. Evaluating the influence of the Red Edge band from RapidEye sensor in quantifying leaf area index for hydrological applications specifically focussing on plant canopy interception

    Science.gov (United States)

    Dube, Timothy; Mutanga, Onisimo; Sibanda, Mbulisi; Shoko, Cletah; Chemura, Abel

    2017-08-01

    Reliable and accurate quantification of plant Leaf Area Index (LAI) is critical in understanding its role in reducing runoff. The main aim of the present study was to evaluate the ability of the Red Edge (RE) band derived from RapidEye in estimating LAI for applications in quantifying canopy interception at landscape scale. To achieve this objective, the study also compares the predictive power of two machine learning algorithms (Random Forest-RF and Stochastic Gradient Boosting-SGB) in estimating LAI. Comparatively, the results of the study have demonstrated that the inclusion of spectral information derived from the Red Edge band yields high accurate LAI estimates, when compared to the use of traditional traditional Red, Green, Blue and Near Infra-Red (traditional RGBNIR) spectral information. The results indicate that the use of the four traditional RGBNIR bands yielded comparatively lower R2 values and high Root Mean Squares, Mean Absolute Error (Pinus taeda: R2 of 0.60; the lowest RMSE (0.35 m2/m2) and MAE of 28); whereas the use of integration of traditional RGBNIR + RE in more accurate LAI estimates (Pinus taeda: R2 = 0.65; RMSE = 0.30 m2/m2) and the lowest MAE of 0.23). These findings therefore underscores the importance of new generation multispectral sensors with strategically-position bands and machine learning algorithms in estimating LAI for quantifying canopy interception, especially in resource-poor areas.

  4. Winter wheat yield estimation of remote sensing research based on WOFOST crop model and leaf area index assimilation

    Science.gov (United States)

    Chen, Yanling; Gong, Adu; Li, Jing; Wang, Jingmei

    2017-04-01

    Accurate crop growth monitoring and yield predictive information are significant to improve the sustainable development of agriculture and ensure the security of national food. Remote sensing observation and crop growth simulation models are two new technologies, which have highly potential applications in crop growth monitoring and yield forecasting in recent years. However, both of them have limitations in mechanism or regional application respectively. Remote sensing information can not reveal crop growth and development, inner mechanism of yield formation and the affection of environmental meteorological conditions. Crop growth simulation models have difficulties in obtaining data and parameterization from single-point to regional application. In order to make good use of the advantages of these two technologies, the coupling technique of remote sensing information and crop growth simulation models has been studied. Filtering and optimizing model parameters are key to yield estimation by remote sensing and crop model based on regional crop assimilation. Winter wheat of GaoCheng was selected as the experiment object in this paper. And then the essential data was collected, such as biochemical data and farmland environmental data and meteorological data about several critical growing periods. Meanwhile, the image of environmental mitigation small satellite HJ-CCD was obtained. In this paper, research work and major conclusions are as follows. (1) Seven vegetation indexes were selected to retrieve LAI, and then linear regression model was built up between each of these indexes and the measured LAI. The result shows that the accuracy of EVI model was the highest (R2=0.964 at anthesis stage and R2=0.920 at filling stage). Thus, EVI as the most optimal vegetation index to predict LAI in this paper. (2) EFAST method was adopted in this paper to conduct the sensitive analysis to the 26 initial parameters of the WOFOST model and then a sensitivity index was constructed

  5. Screening for diabetic retinopathy in rural area using single-field, digital fundus images.

    Science.gov (United States)

    Ruamviboonsuk, Paisan; Wongcumchang, Nattapon; Surawongsin, Pattamaporn; Panyawatananukul, Ekchai; Tiensuwan, Montip

    2005-02-01

    To evaluate the practicability of using single-field, 2.3 million-pixel, digital fundus images for screening of diabetic retinopathy in rural areas. All diabetic patients who regularly attended the diabetic clinic at Kabcheang Community Hospital, located at 15 kilometers from the Thailand-Cambodia border, were appointed to the hospital for a 3-day diabetic retinopathy screening programme. The fundi of all patients were captured in single-field, 45 degrees, 2.3 million-pixel images using nonmydriatic digital fundus camera and then sent to a reading center in Bangkok. The fundi were also examined through dilated pupils by a retinal specialist at this hospital. The grading of diabetic retinopathy from two methods was compared for an exact agreement. The average duration of single digital fundus image capture was 2 minutes. The average file size of each image was 750 kilobytes. The average duration of single image transmission to a reading center in Bangkok via satellite was 3 minutes; via a conventional telephone line was 8 minutes. Of all 150 patients, 130 were assessed for an agreement between dilated fundus examination and digital fundus images in diagnosis of diabetic retinopathy. The exact agreement was 0.87, the weighted kappa statistics was 0.74. The sensitivity of digital fundus images in detecting diabetic retinopathy was 80%, the specificity was 96%. For diabetic macular edema the exact agreement was 0.97, the weighted kappa was 0.43, the sensitivity was 43%, and the specificity was 100%. The image capture of the nonmydriatic digital fundus camera is suitable for screening of diabetic retinopathy and single-field digital fundus images are potentially acceptable tools for the screening. The real-time image transmission via telephone lines to remote reading center, however, may not be practical for routine diabetic retinopathy screening in rural areas.

  6. REGIONAL DIFFERENCES IN THE AMOUNTS OF SINGLE AREA PAYMENT SCHEME IN AGRICULTURE

    Directory of Open Access Journals (Sweden)

    Hanna Teszbir

    2014-09-01

    Full Text Available The article discusses the causes of regional variation in the direct payments. The publication data has been used from ARiMR, publications which spans the time included the amount of subsidies paid throughout the post-accession period. Both at national and regional level, the total amount of payments increased from year to year, average 10%, which was connected to the principle phasing in. The amount of aid received by individual regions and individual farms varied widely, which had a direct relationship with the agrarian structure and the average total area of farms in these areas. The bigger number of small farms, as well as the smaller average total surface area of a single voivodeship, the lower sum of the payments.

  7. Fusing Cubesat and Landsat 8 data for near-daily mapping of leaf area index at 3 m resolution

    Science.gov (United States)

    McCabe, M.; Houborg, R.

    2017-12-01

    Constellations of small cubesats are emerging as a relatively inexpensive observational resource with the potential to overcome spatio-temporal constraints of traditional single-sensor satellite missions. With more than 130 compact 3U (i.e., 10 x 10 x 30 cm) cubesats currently in orbit, the company "Planet" has realized near-daily image capture in RGB and the near-infrared (NIR) at 3 m resolution for every location on the earth. However cross-sensor inconsistencies can be a limiting factor, which result from relatively low signal-to-noise ratios, varying overpass times, and sensor-specific spectral response functions. In addition, the sensor radiometric information content is more limited compared to conventional satellite systems such as Landsat. In this study, a synergistic machine-learning framework utilizing Planet, Landsat 8, and MODIS data is developed to produce Landsat 8 consistent LAI with a factor of 10 increase in spatial resolution and a daily observing potential, globally. The Cubist machine-learning technique is used to establish scene-specific links between scale-consistent cubesat RGB+NIR imagery and Landsat 8 LAI. The scheme implements a novel LAI target sampling technique for model training purposes, which accounts for changes in cover conditions over the cubesat and Landsat acquisition timespans. Results over an agricultural region in Saudi Arabia highlight the utility of the approach for detecting high frequency (i.e., near-daily) and fine-scale (i.e., 3 m) intra-field dynamics in LAI with demonstrated potential for timely identification of developing crop risks. The framework maximizes the utility of ultra-high resolution cubesat data for agricultural management and resource efficiency optimization at the precision scale.

  8. Visceral adipose tissue area measurement at a single level: can it represent visceral adipose tissue volume?

    Science.gov (United States)

    Noumura, Yusuke; Kamishima, Tamotsu; Sutherland, Kenneth; Nishimura, Hideho

    2017-08-01

    Measurement of visceral adipose tissue (VAT) needs to be accurate and sensitive to change for risk monitoring. The purpose of this study is to determine the CT slice location where VAT area can best reflect changes in VAT volume and body weight. 60 plain abdominal CT images from 30 males [mean age (range) 51 (41-68) years, mean body weight (range) 71.1 (101.9-50.9) kg] who underwent workplace screenings twice within a 1-year interval were evaluated. Automatically calculated and manually corrected areas of the VAT of various scan levels using "freeform curve" region of interest on CT were recorded and compared with body weight changes. The strongest correlations of VAT area with VAT volume and body weight changes were shown in a slice 3 cm above the lower margin of L3 with r values of 0.853 and 0.902, respectively. VAT area measurement at a single level 3 cm above the lower margin of the L3 vertebra is feasible and can reflect changes in VAT volume and body weight. Advances in knowledge: As VAT area at a CT slice 3cm above the lower margin of L3 can best reflect interval changes in VAT volume and body weight, VAT area measurement should be selected at this location.

  9. Solution coating of large-area organic semiconductor thin films with aligned single-crystalline domains

    KAUST Repository

    Diao, Ying

    2013-06-02

    Solution coating of organic semiconductors offers great potential for achieving low-cost manufacturing of large-area and flexible electronics. However, the rapid coating speed needed for industrial-scale production poses challenges to the control of thin-film morphology. Here, we report an approach - termed fluid-enhanced crystal engineering (FLUENCE) - that allows for a high degree of morphological control of solution-printed thin films. We designed a micropillar-patterned printing blade to induce recirculation in the ink for enhancing crystal growth, and engineered the curvature of the ink meniscus to control crystal nucleation. Using FLUENCE, we demonstrate the fast coating and patterning of millimetre-wide, centimetre-long, highly aligned single-crystalline organic semiconductor thin films. In particular, we fabricated thin films of 6,13-bis(triisopropylsilylethynyl) pentacene having non-equilibrium single-crystalline domains and an unprecedented average and maximum mobilities of 8.1±1.2 cm2 V-1 s -1 and 11 cm2 V-1 s-1. FLUENCE of organic semiconductors with non-equilibrium single-crystalline domains may find use in the fabrication of high-performance, large-area printed electronics. © 2013 Macmillan Publishers Limited. All rights reserved.

  10. Relationship between spectral reflectance and leaf area index in needleleaf forest: The effect of three-dimensional forest structure and clumping

    International Nuclear Information System (INIS)

    Kobayashi, H.

    2008-01-01

    Toward the reliable estimation of leaf area index (LAI) and fraction of absorbed photosynthetically active radiation (FAPAR), the relationship between LAI/FAPAR and bidirectional reflectance factor (BRF) at the top of canopy should be accurately modeled by the radiation transfer models. These relationships vary with the forest landscape due to its horizontal heterogeneity and needles clumping within shoot. In this study, the effect of the forest heterogeneity on the relationships between BRF and LAI, and NDVI and LAI/FAPAR were examined through the three-dimensional radiative transfer simulation, and were compared with the results from one-dimensional radiative transfer simulation. In addition to the simulation, limitation of one-dimensional radiative transfer simulation was evaluated. The results showed that BRF at red and near infrared, and NDVI had large variations with different forest landscape under the same LAI conditions. However the relationship between NDVI and LAI, and NDVI and FAPAR derived from dense canopy condition were quite similar to the results from one-dimensional model. If we add the shoot clumping effect in one dimensional radiative transfer model as a universal parameter for three-dimensional effect of the forest, one dimensional radiative transfer model can work well for the BRF simulation in spatially heterogeneous landscape except higher LAI conditions

  11. Extraction of Rice Heavy Metal Stress Signal Features Based on Long Time Series Leaf Area Index Data Using Ensemble Empirical Mode Decomposition.

    Science.gov (United States)

    Tian, Lingwen; Liu, Xiangnan; Zhang, Biyao; Liu, Ming; Wu, Ling

    2017-09-06

    The use of remote sensing technology to diagnose heavy metal stress in crops is of great significance for environmental protection and food security. However, in the natural farmland ecosystem, various stressors could have a similar influence on crop growth, therefore making heavy metal stress difficult to identify accurately, so this is still not a well resolved scientific problem and a hot topic in the field of agricultural remote sensing. This study proposes a method that uses Ensemble Empirical Mode Decomposition (EEMD) to obtain the heavy metal stress signal features on a long time scale. The method operates based on the Leaf Area Index (LAI) simulated by the Enhanced World Food Studies (WOFOST) model, assimilated with remotely sensed data. The following results were obtained: (i) the use of EEMD was effective in the extraction of heavy metal stress signals by eliminating the intra-annual and annual components; (ii) LAI df (The first derivative of the sum of the interannual component and residual) can preferably reflect the stable feature responses to rice heavy metal stress. LAI df showed stability with an R² of greater than 0.9 in three growing stages, and the stability is optimal in June. This study combines the spectral characteristics of the stress effect with the time characteristics, and confirms the potential of long-term remotely sensed data for improving the accuracy of crop heavy metal stress identification.

  12. Physiological aspects of stevia (Stevia rebaudiana Bertoni) in the Colombian Caribbean: I. Effects of attendant radiation on leaf area and biomass distribution

    International Nuclear Information System (INIS)

    Jarma, A.; Rengifo, T.; Araméndiz-Tatis, H.

    2005-01-01

    Stevia rebaudiana Bertoni is one of the Stevia genus' 154 members. The sweetening component of its leaves is due to dipterpene glycosides. The major steviol glycosides are: stevioside, rebaudioside A, rebaudioside C and dulcoside A. This research was carried out at Montería (Colombia); it evaluated the effect of four levels of attendant radiation in the climatic conditions found in the Sinú river valley on the physiological behaviour of S. rebaudiana. A completely random design was used, employing percentage of attendant radiation (19%, 24%, 56% and 100%) and Stevia genotypes ('Morita 1' and 'Morita 2') as factors. The results indicated that the leaf area of 'Morita 2' was always bigger than that of 'Morita 1' and radiation level did not influence this variable. The biggest accumulation of dry mass on leaves returned the highest levels of attendant radiation (100% and 56%). 'Morita 2' was better able to accumulate dry mass than 'Morita 1'. The fact that leaves accumulated more biomass than the stems during the first 60 d after being transplanted showed that plants were working to strengthen their photosynthetic ability during this period. This was followed by a greater migration of substances produced by photosynthesis towards the stems. The tendency stabilised toward both demands at the end of the period being studied [es

  13. Retrieval of Seasonal Leaf Area Index from Simulated EnMAP Data through Optimized LUT-Based Inversion of the PROSAIL Model

    Directory of Open Access Journals (Sweden)

    Matthias Locherer

    2015-08-01

    Full Text Available The upcoming satellite mission EnMAP offers the opportunity to retrieve information on the seasonal development of vegetation parameters on a regional scale based on hyperspectral data. This study aims to investigate whether an analysis method for the retrieval of leaf area index (LAI, developed and validated on the 4 m resolution scale of six airborne datasets covering the 2012 growing period, is transferable to the spaceborne 30 m resolution scale of the future EnMAP mission. The widely used PROSAIL model is applied to generate look-up-table (LUT libraries, by which the model is inverted to derive LAI information. With the goal of defining the impact of different selection criteria in the inversion process, different techniques for the LUT based inversion are tested, such as several cost functions, type and amount of artificial noise, number of considered solutions and type of averaging method. The optimal inversion procedure (Laplace, median, 4% inverse multiplicative noise, 350 out of 100,000 averages is identified by validating the results against corresponding in-situ measurements (n = 330 of LAI. Finally, the best performing LUT inversion (R2 = 0.65, RMSE = 0.64 is adapted to simulated EnMAP data, generated from the airborne acquisitions. The comparison of the retrieval results to upscaled maps of LAI, previously validated on the 4 m scale, shows that the optimized retrieval method can successfully be transferred to spaceborne EnMAP data.

  14. Using the Normalized Differential Wetness Index to Scale Leaf Area Index, Create Three-Dimensional Classification Maps, and Scale Seasonal Evapotranspiration Depletions in Canopies Along the Middle Rio Grande Riparian CorridorCorridor

    Science.gov (United States)

    McDonnell, D. E.; Cleverly, J. R.; Dahm, C. N.; Coonrod, J. A.

    2005-12-01

    This research creates temporally and spatially explicit data layers of vegetation, leaf area index (LAI), three dimensional (3D) vegetation classification maps, and seasonal evapotranspiration (ET) depletions along the middle Rio Grande riparian corridor. The first part of this work produces two dimensional (2D) classification maps of native and non-native canopy vegetation using temporal patterns and the decision tree classifier in ENVI 4.0 (Research Systems Inc. Boulder, Colorado). The second part of this work correlates the normalized differential wetness index (NDWI) with field measurements of plant area index (PAI), stem area index (SAI), and leaf area index (LAI) using the LAI-2000 Plant Canopy Analyzer (PCA) (LICOR Inc., Lincoln, Nebraska). SAI is measured in winter to capture only branches and stems. PAI is measured during the growing season. Field measurements taken within 10 days of image capture dates provide adequate correlations though the closer the dates the better the correlation. LAI represents the surface area of active green leafy vegetation. NDWI correlates with both PAI and estimated LAI in both Tamarisk chinensis and Populus deltoides ssp. Wislizeni sites better than the more traditional normalized differential vegetation index (NDVI). This study also suggests that winter PCA measurements approximate SAI which should be subtracted from PAI in woody vegetation like T. chinensis and Salix exigua stands. The results show that correcting for leaf geometry by multiplying T. chinensis areas with cylindrical cladophylls by pi and the remaining flat leaf vegetation by two yields the best relationship between NDWI and total LAI. The 2Dclassification maps can be placed on top of relief maps of LAI to produce 3D classification maps. The final part of this research scales ET from four 3D eddy covariance towers located in two T. chinensis and two P. deltoides study sites. ET is regressed with LAI, percent daylight (PD), and average hourly incoming net

  15. Estimativa da área foliar de meloeiro em estádios fenológicos por fotos digitais Estimate of the leaf area of melon plant in growing stages for digital photos

    Directory of Open Access Journals (Sweden)

    Sidinei José Lopes

    2007-08-01

    Full Text Available O objetivo deste trabalho foi avaliar a precisão do método de fotos digitais na estimativa da área foliar de meloeiro e encontrar modelos matemáticos de estimativa da área foliar em função de medidas lineares da folha para diferentes estádios fenológicos. Foram fotografadas todas as folhas ímpares de 8 plantas após transplante definitivo, através de câmera fotográfica digital, resultando, durante todo o ciclo da cultura, em 4.188 fotos, das quais mediu-se a área foliar, o comprimento e a largura da folha, por meio do software Sigma Scan Pro v. 5.0, Jandel Scientific. Para verificar a precisão do método de fotos digitais, retirou-se uma amostra de 40 folhas, de onde foram obtidas a área foliar através do método padrão de discos foliares e pelo método de fotos. Foi encontrada uma correlação de 0,99 entre o método padrão (discos e o de fotos. O método de fotos digitais pode ser utilizado para estimar a área foliar da cultura de meloeiro, e a estimativa da área foliar de meloeiro por estádio fenológico apresenta maior precisão, sendo a maior variabilidade na estimativa da área da folha observada no período reprodutivo. A largura máxima da folha de meloeiro é a medida linear que melhor estima a área foliar.This experiment was aimed at evaluating the precision of digital photos in estimating the leaf area of watermelon plants and to find mathematical models that estimates leaf area as a function of leaf linear measurements at different growth stages. All odd leaves of eight plants were photographed after being established on the field using a digital camera that resulted in 4,188 photos in which length and width were measured using a Sigma Scan Pro v. 5.0 Jandel Scientific software. In order to estimate the precision of the digital photos method, a sample consisting of 40 leaves was taken and leaf area measured using the standard leaf disks and the photo method. A 0.99 correlation coefficient was detected between

  16. Comparative Analysis of Chinese HJ-1 CCD, GF-1 WFV and ZY-3 MUX Sensor Data for Leaf Area Index Estimations for Maize

    Directory of Open Access Journals (Sweden)

    Jing Zhao

    2018-01-01

    Full Text Available In recent years, China has developed and launched several satellites with high spatial resolutions, such as the resources satellite No. 3 (ZY-3 with a multi-spectral camera (MUX and 5.8 m spatial resolution, the satellite GaoFen No. 1 (GF-1 with a wide field of view (WFV camera and 16 m spatial resolution, and the environment satellite (HJ-1A/B with a charge-coupled device (CCD sensor and 30 m spatial resolution. First, to analyze the potential application of ZY-3 MUX, GF-1 WFV, and HJ-1 CCD to extract the leaf area index (LAI at the regional scale, this study estimated LAI from the relationships between physical model-based spectral vegetation indices (SVIs and LAI values that were generated from look-up tables (LUTs, simulated from the combination of the PROSPECT-5B leaf model and the scattering by arbitrarily inclined leaves with the hot-spot effect (SAILH canopy reflectance model. Second, to assess the surface reflectance quality of these sensors after data preprocessing, the well-processed surface reflectance products of the Landsat-8 operational land imager (OLI sensor with a convincing data quality were used to compare the performances of ZY-3 MUX, GF-1 WFV, and HJ-1 CCD sensors both in theory and reality. Apart from several reflectance fluctuations, the reflectance trends were coincident, and the reflectance values of the red and near-infrared (NIR bands were comparable among these sensors. Finally, to analyze the accuracy of the LAI estimated from ZY-3 MUX, GF-1 WFV, and HJ-1 CCD, the LAI estimations from these sensors were validated based on LAI field measurements in Huailai, Hebei Province, China. The results showed that the performance of the LAI that was inversed from ZY-3 MUX was better than that from GF-1 WFV, and HJ-1 CCD, both of which tended to be systematically underestimated. In addition, the value ranges and accuracies of the LAI inversions both decreased with decreasing spatial resolution.

  17. Photosynthetic efficiency of healthy leaf area influenced by angular leaf spot severity in bean field/ Influência da severidade de mancha angular na eficiência fotossintética da área foliar sadia de feijoeiro, sob condições de campo

    Directory of Open Access Journals (Sweden)

    Cláudia Vieira Godoy

    2005-06-01

    Full Text Available This paper aimed to show the relationship among healthy leaf area, angular leaf spot severity and bean yield, under field conditions, indicating the influence of this relationship on photosynthetic efficiency of leaf tissue remaining on plants. Leaf area and severity of angular leaf spot [Phaeoisariopsis griseola (Sacc. Ferraris] of bean were weekly assessed, beginning at 30 days after emergence (DAE. Different levels of severity were reached varying the timing of fungicide spraying (fentin hydroxide 0.10% + tebuconazole 0.04%. Variations on total leaf area were consequence of natural variation on plants and also due to different physic and chemical soil conditions among plots. The relation between healthy leaf area duration (HAD and area under disease progress curve (AUDPC and yield (g m-2 presented R2=74.8% and healthy area absorption (HAA, AUDPC and yield (g m-2 presented R2=74.7%. Results indicated reduction of yield when severity (AUDPC was high, even in plots with same level of healthy leaf area. So, the disease influenced the photosynthetic efficiency of healthy leaf area, besides avoiding the production of the necrotic tissue.O objetivo do trabalho foi demonstrar, em parcelas experimentais sob condições de campo, a relação entre área foliar sadia, severidade de mancha angular e produção em feijoeiro indicando a influência desta relação na eficiência fotossintética do tecido foliar remanescentes nas plantas. Área foliar e severidade de mancha angular [Phaeoisariopsis griseola (Sacc. Ferraris] de feijoeiro foram avaliadas semanalmente, iniciando-se aos 30 dias após a emergência (DAE. Obtiveram-se diferentes níveis de severidade variando-se a data de início de aplicação da mistura fungicida (fentin hydroxide 0,10% + tebuconazole 0,04%. Variações na quantidade de área foliar foram obtidas em função da variação inerente entre plantas e das diferenças de condições físicoquímicas encontradas no solo das parcelas

  18. Single-mode ytterbium-doped large-mode-area photonic bandgap rod fiber amplifier

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Scolari, Lara; Broeng, Jes

    2011-01-01

    Enabling Single-Mode (SM) operation in Large-Mode-Area (LMA) fiber amplifiers and lasers is critical, since a SM output ensures high beam quality and excellent pointing stability. In this paper, we demonstrate and test a new design approach for achieving SM LMA rod fibers by using a photonic...... bandgap structure. The structure allows resonant coupling of higher-order modes from the core and acts as a spatially Distributed Mode Filter (DMF). With this approach, we demonstrate passive SM performance in an only ~50cm long and straight ytterbium-doped rod fiber. The amplifier has a mode field...

  19. Full-Waveform, Wide-Swath Lidar Imaging of Forested and Urban Areas in Leaf-On Conditions: Development, Results and Future Direction

    Science.gov (United States)

    Blair, James B.; Hofton, M.; Rabine, David; Welch, Wayne; Ramos, Luis; Padden, Phillip

    2003-01-01

    Full-Waveform lidar measurements provide unprecedented views of the vertical and horizontal structure of vegetation and the topography of the Earth s surface. Utilizing a high signal-to-noise ratio lidar system, larger than typical laser footprints (10-20 m), and the recorded time history of interaction between a short-duration (approx. 10 ns) pulse of laser light and the surface of the Earth, full-waveform lidar is able to simultaneously image sub-canopy topography as well as the vertical structure of any overlying vegetation. These data reveal the true 3-D vegetation structure in leaf-on conditions enabling important biophysical parameters such as above-ground biomass to be estimated with unprecedented accuracy. An airborne lidar mission was conducted July-August 2003 in support of the North America Carbon Program. NASA s Laser Vegetation Imaging Sensor (LVIS) was used to image approximately 2,000 km$^2$ in Maine, New Hampshire, Massachusetts and Maryland. Areas with available ground and other data were included (e.g., experimental forests, FLUXNET sites) in order to facilitate as many bio- and geophysical investigations as possible. Data collected included ground elevation and canopy height measurements for each laser footprint, as well as the vertical distribution of intercepted surfaces. Data will be publicly distributed within 6- 12 months of collection. Further details of the mission, including the lidar system technology, the locations of the mapped areas, and examples of the numerous data products that can be derived from the return waveform data products will be presented. Future applications including detection of ground and vegetation canopy changes and a spaceborne implementation of wide-swath, full-waveform imaging lidar will also be discussed.

  20. Comparing the Dry Season In-Situ Leaf Area Index (LAI Derived from High-Resolution RapidEye Imagery with MODIS LAI in a Namibian Savanna

    Directory of Open Access Journals (Sweden)

    Manuel J. Mayr

    2015-04-01

    Full Text Available The Leaf Area Index (LAI is one of the most frequently applied measures to characterize vegetation and its dynamics and functions with remote sensing. Satellite missions, such as NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS operationally produce global datasets of LAI. Due to their role as an input to large-scale modeling activities, evaluation and verification of such datasets are of high importance. In this context, savannas appear to be underrepresented with regards to their heterogeneous appearance (e.g., tree/grass-ratio, seasonality. Here, we aim to examine the LAI in a heterogeneous savanna ecosystem located in Namibia’s Owamboland during the dry season. Ground measurements of LAI are used to derive a high-resolution LAI model with RapidEye satellite data. This model is related to the corresponding MODIS LAI/FPAR (Fraction of Absorbed Photosynthetically Active Radiation scene (MOD15A2 in order to evaluate its performance at the intended annual minimum during the dry season. Based on a field survey we first assessed vegetation patterns from species composition and elevation for 109 sites. Secondly, we measured in situ LAI to quantitatively estimate the available vegetation (mean = 0.28. Green LAI samples were then empirically modeled (LAImodel with high resolution RapidEye imagery derived Difference Vegetation Index (DVI using a linear regression (R2 = 0.71. As indicated by several measures of model performance, the comparison with MOD15A2 revealed moderate consistency mostly due to overestimation by the aggregated LAImodel. Model constraints aside, this study may point to important issues for MOD15A2 in savannas concerning the underlying MODIS Land Cover product (MCD12Q1 and a potential adjustment by means of the MODIS Burned Area product (MCD45A1.

  1. Effects of controlled-release fertilizer on leaf area index and fruit yield in high-density soilless tomato culture using low node-order pinching.

    Science.gov (United States)

    Kinoshita, Takafumi; Yano, Takayoshi; Sugiura, Makoto; Nagasaki, Yuji

    2014-01-01

    To further development of a simplified fertigation system using controlled-release fertilizers (CRF), we investigated the effects of differing levels of fertilizers and plant density on leaf area index (LAI), fruit yields, and nutrient use in soilless tomato cultures with low node-order pinching and high plant density during spring-summer (SS), summer-fall (SF), and fall-winter (FW) seasons. Plants were treated with 1 of 3 levels of CRF in a closed system, or with liquid fertilizer (LF) with constant electrical conductivity (EC) in a drip-draining system. Two plant densities were examined for each fertilizer treatment. In CRF treatments, LAI at pinching increased linearly with increasing nutrient supply for all cropping seasons. In SS, both light interception by plant canopy at pinching and total marketable fruit yield increased linearly with increasing LAI up to 6 m(2) · m(-2); the maximization point was not reached for any of the treatments. In FW, both light interception and yield were maximized at an LAI of approximately 4. These results suggest that maximizing the LAI in SS and FW to the saturation point for light interception is important for increasing yield. In SF, however, the yield maximized at an LAI of approximately 3, although the light interception linearly increased with increasing LAI, up to 4.5. According to our results, the optimal LAI at pinching may be 6 in SS, 3 in SF, and 4 in FW. In comparing LAI values with similar fruit yield, we found that nutrient supply was 32-46% lower with the CRF method than with LF. In conclusion, CRF application in a closed system enables growers to achieve a desirable LAI to maximize fruit yield with a regulated amount of nutrient supply per unit area. Further, the CRF method greatly reduced nutrient use without decreasing fruit yield at similar LAIs, as compared to the LF method.

  2. Effects of controlled-release fertilizer on leaf area index and fruit yield in high-density soilless tomato culture using low node-order pinching.

    Directory of Open Access Journals (Sweden)

    Takafumi Kinoshita

    Full Text Available To further development of a simplified fertigation system using controlled-release fertilizers (CRF, we investigated the effects of differing levels of fertilizers and plant density on leaf area index (LAI, fruit yields, and nutrient use in soilless tomato cultures with low node-order pinching and high plant density during spring-summer (SS, summer-fall (SF, and fall-winter (FW seasons. Plants were treated with 1 of 3 levels of CRF in a closed system, or with liquid fertilizer (LF with constant electrical conductivity (EC in a drip-draining system. Two plant densities were examined for each fertilizer treatment. In CRF treatments, LAI at pinching increased linearly with increasing nutrient supply for all cropping seasons. In SS, both light interception by plant canopy at pinching and total marketable fruit yield increased linearly with increasing LAI up to 6 m(2 · m(-2; the maximization point was not reached for any of the treatments. In FW, both light interception and yield were maximized at an LAI of approximately 4. These results suggest that maximizing the LAI in SS and FW to the saturation point for light interception is important for increasing yield. In SF, however, the yield maximized at an LAI of approximately 3, although the light interception linearly increased with increasing LAI, up to 4.5. According to our results, the optimal LAI at pinching may be 6 in SS, 3 in SF, and 4 in FW. In comparing LAI values with similar fruit yield, we found that nutrient supply was 32-46% lower with the CRF method than with LF. In conclusion, CRF application in a closed system enables growers to achieve a desirable LAI to maximize fruit yield with a regulated amount of nutrient supply per unit area. Further, the CRF method greatly reduced nutrient use without decreasing fruit yield at similar LAIs, as compared to the LF method.

  3. Evaluation of single implants placed in the posterior mandibular area under immediate loading: a prospective study.

    Science.gov (United States)

    Guidetti, L G C; Monnazzi, M S; Piveta, A C G; Gabrielli, M A C; Gabrielli, M F R; Pereira Filho, V A

    2015-11-01

    The aim of this study was to evaluate the survival of single dental implants subjected to immediate function. Twelve patients with edentulous areas in the posterior mandible were included in the study. All received at least one regular platform dental implant (3.75mm×11mm or 3.75mm×13mm). Clinical and radiographic parameters were evaluated. The survival rate after 12 months was 83.3%. The implants showed no clinical mobility, had implant stability quotient values (ISQ; Osstell) around 70, bone loss of up to 2mm, and a probing depth of ≤3mm. Although the posterior mandible is an area in which the immediate loading of dental implants should be performed with caution, this treatment presented a good success rate in the present study sample. Copyright © 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  4. Lidar-based Evaluation of Sub-pixel Forest Structural Characteristics and Sun-sensor Geometries that Influence MODIS Leaf Area Index Product Accuracy and Retrieval Quality

    Science.gov (United States)

    Jensen, J.; Humes, K. S.

    2010-12-01

    Leaf Area Index (LAI) is an important structural component of vegetation because the foliar surface of plants largely controls the exchange of water, nutrients, and energy within terrestrial ecosystems. Because LAI is a key variable used to model water, energy, and biogeochemical cycles, Moderate Resolution Imaging Spectroradiometer (MODIS) LAI products are widely used in many studies to better understand and quantify exchanges between the terrestrial surface and the atmosphere. Within the last decade, significant resources and efforts have been invested toward MODIS LAI validation for a variety of biome types and a suite of published work has provided valuable feedback on the agreement between MODIS-derived LAI via radiative transfer (RT) inversion compared to multispectral-based empirical estimates of LAI. Our study provides an alternative assessment of the MODIS LAI product for a 58,000 ha evergreen needleleaf forest located in the western Rocky Mountain range in northern Idaho by using lidar data to model (R2=0.86, RMSE=0.76) and map fine-scale estimates of vegetation structure over a region for which multispectral LAI estimates were unacceptable. In an effort to provide feedback on algorithm performance, we evaluated the agreement between lidar-modeled and MODIS-retrieved LAI by specific MODIS LAI retrieval algorithm and product quality definitions. We also examined the sub-pixel vegetation structural conditions and satellite-sensor geometries that tend to influence MODIS LAI retrieval algorithm and product quality over our study area. Our results demonstrate a close agreement between lidar LAI and MODIS LAI retrieved using the main RT algorithm and consistently large MODIS LAI overestimates for pixels retrieved from a saturated set of RT solutions. Our evaluation also illuminated some conditions for which sub-pixel structural characteristics and sun-sensor geometries influenced retrieval quality and product agreement. These conditions include: 1) the

  5. Large-Area WS2 Film with Big Single Domains Grown by Chemical Vapor Deposition

    Science.gov (United States)

    Liu, Pengyu; Luo, Tao; Xing, Jie; Xu, Hong; Hao, Huiying; Liu, Hao; Dong, Jingjing

    2017-10-01

    High-quality WS2 film with the single domain size up to 400 μm was grown on Si/SiO2 wafer by atmospheric pressure chemical vapor deposition. The effects of some important fabrication parameters on the controlled growth of WS2 film have been investigated in detail, including the choice of precursors, tube pressure, growing temperature, holding time, the amount of sulfur powder, and gas flow rate. By optimizing the growth conditions at one atmospheric pressure, we obtained tungsten disulfide single domains with an average size over 100 μm. Raman spectra, atomic force microscopy, and transmission electron microscopy provided direct evidence that the WS2 film had an atomic layer thickness and a single-domain hexagonal structure with a high crystal quality. And the photoluminescence spectra indicated that the tungsten disulfide films showed an evident layer-number-dependent fluorescence efficiency, depending on their energy band structure. Our study provides an important experimental basis for large-area, controllable preparation of atom-thick tungsten disulfide thin film and can also expedite the development of scalable high-performance optoelectronic devices based on WS2 film.

  6. The development of a single-crystal fiber-array scintillator area detector

    International Nuclear Information System (INIS)

    Loong, Chun; Vitt, Richard; Sayir, Ali; Sayir, Haluk

    2001-01-01

    The scientific output of a neutron instrument is directly proportional to the effectiveness of its detector system-coverage of scattering area, pixel resolution, counting efficiency, signal-to-noise ratio, life time and cost. The current neutron scintillator detectors employ mainly 6 Li-doped glass and ZnS, both of which present well-know limitations such as low light output, high gamma sensitivity in the case of 6 Li-glass and optical opacity in the case of ZnS. We aim to develop a position-sensitive, flight-time differentiable, efficient and cost-effective neutron detector system based on single-crystal scintillator fiber-arrays. The laser-heated melt modulation fiber growth technology developed at NASA provides the means to grow high-purity single-crystal fibers or rods of variable diameters (200 μm to 5 mm) and essentially unlimited length. Arrays of such fibers can be tailored to meet the requirements of pixel size, geometric configuration, and coverage area for a detector system. We report a plan in the growth and characterization of scintillators based on lithium silicates and boron aluminates using Ce as activator. (author)

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

    African Journals Online (AJOL)

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

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

    African Journals Online (AJOL)

    Jane

    2011-06-22

    Jun 22, 2011 ... herbagreen (HG), humic acid (HA), combined foliar fertilizer (CFF) and HG+CFF performed in the. Müşküle grape variety grafted on 5 BB rootstock on fresh or pickled leaf size and leaf raw cellulose content. HA application increased leaf area and leaf water content values whereas HG+CFF application.

  9. Efeito da irrigação e da ontogenia sobre a estimativa da área foliar de Hancornia speciosa Gómez (mangabeira Effect of irrigation and ontogeny in estimating the leaf area of Hancornia speciosa Gómez (mangabeira

    Directory of Open Access Journals (Sweden)

    Francisco de Almeida Lobo

    2010-09-01

    Full Text Available A estimativa da área foliar por meio de curvas de regressão que empregam o produto do comprimento pela largura do limbo como variável independente, é uma prática comumente empregada na análise de crescimento vegetal. Entretanto, dependendo da natureza do material vegetal e das condições de cultivo, é possível a ocorrência de variações que afetam essa relação alométrica, o que implica a não universalidade de uma única curva de regressão. Devido a esse problema, o presente trabalho teve como objetivo realizar uma avaliação do efeito da irrigação e da ontogenia sobre a estimativa da área foliar da Hancornia speciosa, para testar a hipótese de que a irrigação afetaria tal relação alométrica. Verificou-se que os modelos de regressão obtidos para as plantas irrigadas e para as não irrigadas diferiram entre si, sendo que houve a necessidade da inclusão da área foliar específica no modelo de estimativa da área foliar das plantas não irrigadas. A não inclusão dessa variável no modelo de regressão acarretou uma diferença de estimativa que se incrementou com a redução da área foliar específica. Em folhas recém-expandidas de plantas irrigadas e não irrigadas, verificou-se diferença na área foliar específica devida à alteração na massa seca e não associada à largura dos tecidos foliares.Leaf area estimation by regression curves using the product of the length by the breadth of the leaf blade as an independent variable is commonly used in plant growth analysis. However, depending on the nature of the plant species and the farming conditions,it is possible to find variations which affect this allometric relationship, leading to non-universality of a single regression curve. Due to this problem, the present work aimed to evaluate the effect of irrigation and ontogeny in estimating the leaf area of Hancornia speciosa to test the hypothesis that the irrigation would affect such allometric relationship. It

  10. Spatial variation and seasonal dynamics of leaf-area index in the arctic tundra-implications for linking ground observations and satellite images

    Science.gov (United States)

    Juutinen, Sari; Virtanen, Tarmo; Kondratyev, Vladimir; Laurila, Tuomas; Linkosalmi, Maiju; Mikola, Juha; Nyman, Johanna; Räsänen, Aleksi; Tuovinen, Juha-Pekka; Aurela, Mika

    2017-09-01

    Vegetation in the arctic tundra typically consists of a small-scale mosaic of plant communities, with species differing in growth forms, seasonality, and biogeochemical properties. Characterization of this variation is essential for understanding and modeling the functioning of the arctic tundra in global carbon cycling, as well as for evaluating the resolution requirements for remote sensing. Our objective was to quantify the seasonal development of the leaf-area index (LAI) and its variation among plant communities in the arctic tundra near Tiksi, coastal Siberia, consisting of graminoid, dwarf shrub, moss, and lichen vegetation. We measured the LAI in the field and used two very-high-spatial resolution multispectral satellite images (QuickBird and WorldView-2), acquired at different phenological stages, to predict landscape-scale patterns. We used the empirical relationships between the plant community-specific LAI and degree-day accumulation (0 °C threshold) and quantified the relationship between the LAI and satellite NDVI (normalized difference vegetation index). Due to the temporal difference between the field data and satellite images, the LAI was approximated for the imagery dates, using the empirical model. LAI explained variation in the NDVI values well (R 2 adj. 0.42-0.92). Of the plant functional types, the graminoid LAI showed the largest seasonal amplitudes and was the main cause of the varying spatial patterns of the NDVI and the related LAI between the two images. Our results illustrate how the short growing season, rapid development of the LAI, yearly climatic variation, and timing of the satellite data should be accounted for in matching imagery and field verification data in the Arctic region.

  11. Calibration of a Species-Specific Spectral Vegetation Index for Leaf Area Index (LAI Monitoring: Example with MODIS Reflectance Time-Series on Eucalyptus Plantations

    Directory of Open Access Journals (Sweden)

    Guerric le Maire

    2012-11-01

    Full Text Available The leaf area index (LAI is a key characteristic of forest ecosystems. Estimations of LAI from satellite images generally rely on spectral vegetation indices (SVIs or radiative transfer model (RTM inversions. We have developed a new and precise method suitable for practical application, consisting of building a species-specific SVI that is best-suited to both sensor and vegetation characteristics. Such an SVI requires calibration on a large number of representative vegetation conditions. We developed a two-step approach: (1 estimation of LAI on a subset of satellite data through RTM inversion; and (2 the calibration of a vegetation index on these estimated LAI. We applied this methodology to Eucalyptus plantations which have highly variable LAI in time and space. Previous results showed that an RTM inversion of Moderate Resolution Imaging Spectroradiometer (MODIS near-infrared and red reflectance allowed good retrieval performance (R2 = 0.80, RMSE = 0.41, but was computationally difficult. Here, the RTM results were used to calibrate a dedicated vegetation index (called “EucVI” which gave similar LAI retrieval results but in a simpler way. The R2 of the regression between measured and EucVI-simulated LAI values on a validation dataset was 0.68, and the RMSE was 0.49. The additional use of stand age and day of year in the SVI equation slightly increased the performance of the index (R2 = 0.77 and RMSE = 0.41. This simple index opens the way to an easily applicable retrieval of Eucalyptus LAI from MODIS data, which could be used in an operational way.

  12. Estimation and Validation of RapidEye-Based Time-Series of Leaf Area Index for Winter Wheat in the Rur Catchment (Germany

    Directory of Open Access Journals (Sweden)

    Muhammad Ali

    2015-03-01

    Full Text Available Leaf Area Index (LAI is an important variable for numerous processes in various disciplines of bio- and geosciences. In situ measurements are the most accurate source of LAI among the LAI measuring methods, but the in situ measurements have the limitation of being labor intensive and site specific. For spatial-explicit applications (from regional to continental scales, satellite remote sensing is a promising source for obtaining LAI with different spatial resolutions. However, satellite-derived LAI measurements using empirical models require calibration and validation with the in situ measurements. In this study, we attempted to validate a direct LAI retrieval method from remotely sensed images (RapidEye with in situ LAI (LAIdestr. Remote sensing LAI (LAIrapideye were derived using different vegetation indices, namely SAVI (Soil Adjusted Vegetation Index and NDVI (Normalized Difference Vegetation Index. Additionally, applicability of the newly available red-edge band (RE was also analyzed through Normalized Difference Red-Edge index (NDRE and Soil Adjusted Red-Edge index (SARE. The LAIrapideye obtained from vegetation indices with red-edge band showed better correlation with LAIdestr (r = 0.88 and Root Mean Square Devation, RMSD = 1.01 & 0.92. This study also investigated the need to apply radiometric/atmospheric correction methods to the time-series of RapidEye Level 3A data prior to LAI estimation. Analysis of the the RapidEye Level 3A data set showed that application of the radiometric/atmospheric correction did not improve correlation of the estimated LAI with in situ LAI.

  13. Leaf Area Index (LAI Estimation in Boreal Mixedwood Forest of Ontario, Canada Using Light Detection and Ranging (LiDAR and WorldView-2 Imagery

    Directory of Open Access Journals (Sweden)

    Paul Treitz

    2013-10-01

    Full Text Available Leaf Area Index (LAI is an important input variable for forest ecosystem modeling as it is a factor in predicting productivity and biomass, two key aspects of forest health. Current in situ methods of determining LAI are sometimes destructive and generally very time consuming. Other LAI derivation methods, mainly satellite-based in nature, do not provide sufficient spatial resolution or the precision required by forest managers for tactical planning. This paper focuses on estimating LAI from: (i height and density metrics derived from Light Detection and Ranging (LiDAR; (ii spectral vegetation indices (SVIs, in particular the Normalized Difference Vegetation Index (NDVI; and (iii a combination of these methods. For the Hearst Forest of Northern Ontario, in situ measurements of LAI were derived from digital hemispherical photographs (DHPs while remote sensing variables were derived from low density LiDAR (i.e., 1 m−2 and high spatial resolution WorldView-2 data (2 m. Multiple Linear Regression (MLR models were generated using these variables. Results from these analyses demonstrate: (i moderate explanatory power (i.e., R2 = 0.53 for LiDAR height and density metrics that have proven to be related to canopy structure; (ii no relationship when using SVIs; and (iii no significant improvement of LiDAR models when combining them with SVI variables. The results suggest that LiDAR models in boreal forest environments provide satisfactory estimations of LAI, even with narrow ranges of LAI for model calibration. Models derived from low point density LiDAR in a mixedwood boreal environment seem to offer a reliable method of estimating LAI at high spatial resolution for decision makers in the forestry community. This method can be easily incorporated into simultaneous modeling efforts for forest inventory variables using LiDAR.

  14. Enhanced nitrogen removal in single-chamber microbial fuel cells with increased gas diffusion areas

    KAUST Repository

    Yan, Hengjing

    2012-11-23

    Single-chamber microbial fuel cells (MFCs) with nitrifiers pre-enriched at the air cathodes have previously been demonstrated as a passive strategy for integrating nitrogen removal into current-generating bioelectrochemical systems. To further define system design parameters for this strategy, we investigated in this study the effects of oxygen diffusion area and COD/N ratio in continuous-flow reactors. Doubling the gas diffusion area by adding an additional air cathode or a diffusion cloth significantly increased the ammonia and COD removal rates (by up to 115% and 39%), ammonia removal efficiency (by up to 134%), the cell voltage and cathode potentials, and the power densities (by a factor of approximately 2). When the COD/N ratio was lowered from 13 to 3, we found up to 244% higher ammonia removal rate but at least 19% lower ammonia removal efficiency. An increase of COD removal rate by up to 27% was also found when the COD/N ratio was lowered from 11 to 3. The Coulombic efficiency was not affected by the additional air cathode, but decreased by an average of 11% with the addition of a diffusion cloth. Ammonia removal by assimilation was also estimated to understand the ammonia removal mechanism in these systems. These results showed that the doubling of gas diffusion area enhanced N and COD removal rates without compromising electrochemical performance. © 2012 Wiley Periodicals, Inc.

  15. The chlorophyll-deficient golden leaf mutation in cucumber is due to a single nucleotide substitution in CsChlI for magnesium chelatase I subunit

    Science.gov (United States)

    The chlorophyll gives the green color in plants. Any mutations in chloroplhyll biosynthesis or regulation may result in colr changes. Leaf color mutants are common in higher plants, which can be used as markers in crop breeding or as a tool in understanding regulatory mechanisms in chlorophyll biosy...

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

    Science.gov (United States)

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

    2017-11-01

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

  17. THE IMPLICATIONS OF SINGLE EURO PAYMENTS AREA (SEPA ON BANKING EFFICIENCY

    Directory of Open Access Journals (Sweden)

    Mihaita-Cosmin POPOVICI

    2014-09-01

    Full Text Available With the creation of the euro by the Maastricht Treaty in 1992, European integration has deepened. Even with this step done the financial market is fragmented. In order to eliminate this disadvantage, the European Union has taken a number of measures. The first step is the Financial Services Action Plan in 2000, through the Lisbon Strategy. Second is the European Commission Regulation 2560/2001 to harmonise fees for cross border and domestic euro transactions. Third is the first pan-European Automated Clearing House in 2003. Last great step made is the Single Euro Payments Area (SEPA in 2008. In this paper, we want to research the degree of implementation of SEPA by using quantitative indicators: credit transfers, direct debits and payment cards, and the effects of this system on bank efficiency.

  18. Bend-insensitive single-mode photonic crystal fiber with ultralarge effective area for dual applications

    Science.gov (United States)

    Islam, Md. Asiful; Alam, M. Shah

    2013-05-01

    A novel photonic crystal fiber (PCF) having circular arrangement of cladding air holes has been designed and numerically optimized to obtain a bend insensitive single mode fiber with large mode area for both wavelength division multiplexing (WDM) communication and fiber-to-the-home (FTTH) application. The bending loss of the proposed bent PCF lies in the range of 10-3 to 10-4 dB/turn or lower over 1300 to 1700 nm, and 2 × 10-4 dB/turn at the wavelength of 1550 nm for a 30-mm bend radius with a higher order mode (HOM) cut-off frequency below 1200 nm for WDM application. When the whole structure of the PCF is scaled down, a bending loss of 6.78×10-4 dB/turn at 1550 nm for a 4-mm bend radius is obtained, and the loss remains in the order of 10-4 dB/turn over the same range of wavelength with an HOM cut-off frequency below 700 nm, and makes the fiber useful for FTTH applications. Furthermore, this structure is also optimized to show a splice loss near zero for fusion-splicing to a conventional single-mode fiber (SMF).

  19. Large-Area High Aspect Ratio Plasmonic Interference Lithography Utilizing a Single High-k Mode.

    Science.gov (United States)

    Chen, Xi; Yang, Fan; Zhang, Cheng; Zhou, Jing; Guo, L Jay

    2016-04-26

    Plasmonic lithography, which utilizes subwavelength confinement of surface plasmon polartion (SPP) waves, has the capability of breaking the diffraction limit and delivering high resolution. However, all previously reported results suffer from critical issues, such as shallow pattern depth and pattern nonuniformity even over small exposure areas, which limit the application of the technology. In this work, periodic patterns with high aspect ratios and a half-pitch of about 1/6 of the wavelength were achieved with pattern uniformity in square centimeter areas. This was accomplished by designing a special mask and photoresist (PR) system to select a single high spatial frequency mode and incorporating the PR into a waveguide configuration to ensure uniform light exposure over the entire depth of the photoresist layer. In addition to the experimental progress toward large-scale applications of plasmonic interference lithography, the general criteria of designing such an exposure system is also discussed, which can be used for nanoscale fabrication in this fashion for various applications with different requirements for wavelength, pitch, aspect ratio, and structure.

  20. Evidence of the effects of fire on branching and leaf development in cerrado trees

    OpenAIRE

    Souza, João Paulo; Albino, Ana Lúcia S.; Prado, Carlos Henrique B. A.

    2017-01-01

    ABSTRACT We discuss evidence of effects of an accidental fire on shoot growth and leaf development in six cerrado tree species with distinct leaf phenologies. Buds of all six species were marked before shoot and leaf emergence in the dry season. After fire, leaf and shoot growth were monitored weekly and specific leaf area (SLA) was determined. Shoot order was determined in the growing season. Evergreens and semideciduous woody species had rapid leaf and shoot growth and decreased leaf life s...

  1. Difference in the crab fauna of mangrove areas at a southwest Florida and a northeast Australia location: Implications for leaf litter processing

    Science.gov (United States)

    McIvor, C.C.; Smith, T. J.

    1995-01-01

    Existing paradigms suggest that mangrove leaf litter is processed primarily via the detrital pathway in forests in the Caribbean biogeographic realm whereas herbivorous crabs are relatively more important litter processors in the Indo-West Pacific. To test this hypothesis, we used pitfall traps to collect intertidal crabs to characterize the crab fauna in a mangrove estuary in southwest Florida. We also tethered mangrove leaves to determine if herbivorous crabs are major leaf consumers there. We compared the results with previously published data collected in an analogous manner from forests in northeastern Australia. The crab fauna in Rookery Bay, Florida, is dominated by carnivorous xanthid and deposit-feeding ocypodid crabs whereas that of the Murray River in northeastern Australia is dominated by herbivorous grapsid crabs. No leaves tethered at five sites in the forests in Southwest Florida were taken by crabs. This contrasts greatly with reported values of leaf removal by crabs in Australian forests of 28-79% of the leaves reaching the forest floor. These differences in the faunal assemblages and in the fate of marked or tethered leaves provide preliminary support for the hypothesis that leaf litter is in fact processed in fundamentally different ways in the two biogeographic realms.

  2. 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

  3. Application about an one-single-channel online radioactive monitoring equipment used for multiple areas in Tianwan Nuclear Power Plant

    International Nuclear Information System (INIS)

    Li Zhong; Zheng Suhong; Hong Yuanjin

    2012-01-01

    Generally, one online monitoring instrument used for monitoring radioactive is needed for one area of nuclear island workshop in nuclear power plant. This paper will expound one monitoring system which can measure multiple areas by one instrument. It uses a single instrument, through the electromagnetic valve automatically switch and compressor continuous suction, realized the 11 different areas of on-line radioactive monitoring. Since its operation, this monitoring system is running stably, it is available for reference to fellows. (authors)

  4. Data Package for Past and Current Groundwater Flow and Contamination beneath Single-Shell Tank Waste Management Areas

    Energy Technology Data Exchange (ETDEWEB)

    Horton, Duane G.

    2007-03-16

    This appendix summarizes historic and recent groundwater data collected from the uppermost aquifer beneath the 200 East and 200 West Areas. Although the area of interest is the Hanford Site Central Plateau, most of the information discussed in this appendix is at the scale of individual single-shell tank waste management areas. This is because the geologic, and thus the hydraulic, properties and the geochemical properties (i.e., groundwater composition) are different in different parts of the Central Plateau.

  5. Towards ground-truthing of spaceborne estimates of above-ground life biomass and leaf area index in tropical rain forests

    Directory of Open Access Journals (Sweden)

    P. Köhler

    2010-08-01

    Full Text Available The canopy height h of forests is a key variable which can be obtained using air- or spaceborne remote sensing techniques such as radar interferometry or LIDAR. If new allometric relationships between canopy height and the biomass stored in the vegetation can be established this would offer the possibility for a global monitoring of the above-ground carbon content on land. In the absence of adequate field data we use simulation results of a tropical rain forest growth model to propose what degree of information might be generated from canopy height and thus to enable ground-truthing of potential future satellite observations. We here analyse the correlation between canopy height in a tropical rain forest with other structural characteristics, such as above-ground life biomass (AGB (and thus carbon content of vegetation and leaf area index (LAI and identify how correlation and uncertainty vary for two different spatial scales. The process-based forest growth model FORMIND2.0 was applied to simulate (a undisturbed forest growth and (b a wide range of possible disturbance regimes typically for local tree logging conditions for a tropical rain forest site on Borneo (Sabah, Malaysia in South-East Asia. In both undisturbed and disturbed forests AGB can be expressed as a power-law function of canopy height h (AGB = a · hb with an r2 ~ 60% if data are analysed in a spatial resolution of 20 m × 20 m (0.04 ha, also called plot size. The correlation coefficient of the regression is becoming significant better in the disturbed forest sites (r2 = 91% if data are analysed hectare wide. There seems to exist no functional dependency between LAI and canopy height, but there is also a linear correlation (r2 ~ 60% between AGB and the area fraction of gaps in which the canopy is highly disturbed. A reasonable agreement of our results with observations is obtained from a

  6. Reduced uncertainty of regional scale CLM predictions of net carbon fluxes and leaf area indices with estimated plant-specific parameters

    Science.gov (United States)

    Post, Hanna; Hendricks Franssen, Harrie-Jan; Han, Xujun; Baatz, Roland; Montzka, Carsten; Schmidt, Marius; Vereecken, Harry

    2016-04-01

    Reliable estimates of carbon fluxes and states at regional scales are required to reduce uncertainties in regional carbon balance estimates and to support decision making in environmental politics. In this work the Community Land Model version 4.5 (CLM4.5-BGC) was applied at a high spatial resolution (1 km2) for the Rur catchment in western Germany. In order to improve the model-data consistency of net ecosystem exchange (NEE) and leaf area index (LAI) for this study area, five plant functional type (PFT)-specific CLM4.5-BGC parameters were estimated with time series of half-hourly NEE data for one year in 2011/2012, using the DiffeRential Evolution Adaptive Metropolis (DREAM) algorithm, a Markov Chain Monte Carlo (MCMC) approach. The parameters were estimated separately for four different plant functional types (needleleaf evergreen temperate tree, broadleaf deciduous temperate tree, C3-grass and C3-crop) at four different sites. The four sites are located inside or close to the Rur catchment. We evaluated modeled NEE for one year in 2012/2013 with NEE measured at seven eddy covariance sites in the catchment, including the four parameter estimation sites. Modeled LAI was evaluated by means of LAI derived from remotely sensed RapidEye images of about 18 days in 2011/2012. Performance indices were based on a comparison between measurements and (i) a reference run with CLM default parameters, and (ii) a 60 instance CLM ensemble with parameters sampled from the DREAM posterior probability density functions (pdfs). The difference between the observed and simulated NEE sum reduced 23% if estimated parameters instead of default parameters were used as input. The mean absolute difference between modeled and measured LAI was reduced by 59% on average. Simulated LAI was not only improved in terms of the absolute value but in some cases also in terms of the timing (beginning of vegetation onset), which was directly related to a substantial improvement of the NEE estimates in

  7. A new method for estimating the leaf area index of cucumber and tomato plants Um novo método para estimar o índice de área foliar de plantas de pepino e tomate

    Directory of Open Access Journals (Sweden)

    Flávio Favaro Blanco

    2003-12-01

    Full Text Available Non-destructive methods of leaf area measurement are useful for small plant populations, such as experiments with potted plants, and allow the measurement of the same plant several times during the growing period. A methodology was developed to estimate the leaf area index (LAI of cucumber and tomato plants through the evaluation of the leaf area distribution pattern (LADP of the plants and the relative height of the leaves in the plants. Plant and leaf height, as well as the length and width of all leaves were measured and the area of some leaves was determined by a digital area meter. The obtained regression equations were used to estimate the leaf area for all relative heights along the plant. The LADP adjusted to a quadratic model for both crops and LAI were estimated by measuring the length and width of the leaves located at the relative heights representing the mean leaf area of the plants. The LAI estimations presented high precision and accuracy when the proposed methodology was used resulting in time and effort savings and being useful for both crops.Métodos não destrutivos para a medição da área foliar são úteis para pequena população de plantas, como experimentos com plantas conduzidas em vasos, e permitem que a mesma planta seja medida várias vezes durante o período de cultivo. O objetivo desse trabalho foi desenvolver uma metodologia para a estimativa do índice de área foliar (IAF do pepino e do tomate pela determinação do padrão de distribuição de área foliar (PDAF das plantas e da altura relativa da folha que representa a área foliar média da planta. A altura da planta e da folha, assim como o comprimento e a largura de todas as folhas, foram medidos e algumas folhas tiveram sua área determinada por um medidor digital de área foliar. As equações de regressão obtidas foram utilizadas para estimar a área foliar para todas as alturas relativas ao longo da planta. O PDAF ajustou-se a um modelo quadr

  8. Estimation of leaf area for greenhouse cucumber by linear measurements under salinity and grafting Estimativa da área foliar do pepino em ambiente protegido por medidas lineares sob salinidade e enxertia

    Directory of Open Access Journals (Sweden)

    Flávio Favaro Blanco

    2005-08-01

    Full Text Available The measurement of leaf area by linear parameters is a useful tool when plants cannot be destroyed for direct measurement. The objectives of this study were to establish equations to estimate the leaf area of greenhouse-cucumber and to evaluate the effects of salinity and grafting on this estimative. Non-grafted cucumber seedlings, cv. 'Hokushin', were transplanted in a greenhouse and were irrigated with water of different salinities (1.0, 3.2 and 5.0 dS m-1. In the second growing period, the same cultivar was grafted on Cucurbita spp. and the plants were irrigated with water of 1.4, 3.0 and 5.3 dS m-1. Leaves of different sizes were collected from both experiments and leaf area was determined by an integrating area meter. Leaf length (L and width (W were also recorded. An equation for estimating the leaf area from L and W was developed for a given salinity level or grafting condition and estimated well the area of leaves collected in the other treatments. The leaf area (LA of cucumber 'Hokushin' could be estimated using the equation LA = 0.88LW - 4.27, for any grafting and salinity conditions.A determinação da área foliar por medidas lineares é uma ferramenta útil quando as plantas não podem ser destruídas para que a medição direta seja realizada. Os objetivos desse trabalho foram definir equações para a estimativa da área foliar do pepino em ambiente protegido e avaliar os efeitos da salinidade e da a enxertia nessa estimativa. Mudas de pepino, cv. 'Hokushin', não enxertadas, foram transplantadas em um ambiente protegido e irrigadas com água de diferentes salinidades (1,0, 3,2 e 5,0 dS m-1. No segundo período de cultivo, a mesma cultivar foi enxertada sobre Cucurbita spp., sendo as plantas irrigadas com água de 1,4, 3,0 e 5,3 dS m-1. Foram coletadas folhas de diferentes tamanhos dos dois cultivos e dos três tratamentos e a área foliar foi determinada por um medidor de área foliar. O comprimento (C e a largura (L da folha

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

    Directory of Open Access Journals (Sweden)

    Hipólito Medrano

    2015-06-01

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

  10. Phylogenetic Distribution of Leaf Spectra and Optically Derived Functional Traits in the American Oaks

    Science.gov (United States)

    Cavender-Bares, J.; Meireles, J. E.; Couture, J. J.; Kaproth, M.; Townsend, P. A.

    2015-12-01

    Detecting functional traits of species, genotypes and phylogenetic lineages is critical in monitoring functional biodiversity remotely. We examined the phylogenetic distribution of leaf spectra across the American Oaks for 35 species under greenhouse conditions as well as genetic variation in leaf spectra across Central American populations of a single species grown in common gardens in Honduras. We found significant phylogenetic signal in the leaf spectra (Blomberg's K > 1.0), indicating similarity in spectra among close relatives. Across species, full range leaf spectra were used in a Partial Least Squares Discriminant Analysis (PLS-DA) that allowed species calibration (kappa statistic = 0.55). Validation of the model used to detect species (kappa statistic = 0.4) indicated reasonably good detection of individual species within the same the genus. Among four populations from Belize, Costa Rica, Honduras, and Mexico within a single species (Quercus oleoides), leaf spectra were also able to differentiate populations. Ordination of population-level data using dissimilarities of predicted foliar traits, including leaf mass per area (LMA), lignin content, fiber content, chlorophyll a+b, and C:N ratio in genotypes in either watered or unwatered conditions showed significant differentiation among populations and treatments. These results provide promise for remote detection and differentiation of plant functional traits among plant phylogenetic lineages and genotypes, even among closely related populations and species.

  11. The network structure of adaptive governance - A single case study of a fish management area

    Directory of Open Access Journals (Sweden)

    Annica Charlotte Sandström

    2009-09-01

    Full Text Available The challenge of establishing adaptive management systems is a widely discussed topic in the literature on natural resource management. Adaptive management essentially focuses on achieving a governance process that is both sensitive to and has the capacity to continuously react to changes within the ecosystem being managed. The adoption of a network approach that perceives governance structures as social networks, searching for the kind of network features promoting this important feature, has been requested by researchers in the field. In particular, the possibilities associated with the application of a formal network approach, using the tools and concepts of social network analysis (SNA, have been identified as having significant potential for advancing this branch of research. This paper aims to address the relation between network structure and adaptability using an empirical approach. With the point of departure in a previously generated theoretical framework as well as related hypotheses, this paper presents a case study of a governance process within a fish management area in Sweden. The hypotheses state that, although higher levels of network density and centralisation promote the rule-forming process, the level of network heterogeneity is important for the existence and spread of ecological knowledge among the actors involved. According to the empirical results, restricted by the single-case study design, this assumption is still a well-working hypothesis. However, in order to advance our knowledge concerning these issues and test the validity of the hypotheses, more empirical work using a similar approach in multiple case study designs is needed.

  12. SU-E-T-331: Dosimetric Impact of Multileaf Collimator Leaf Width On Stereotactic Radiosurgery (SRS) RapidArc Treatment Plans for Single and Multiple Brain Metastases

    International Nuclear Information System (INIS)

    Hossain, S; Keeling, V; Ahmad, S; Algan, O

    2015-01-01

    Purpose: To determine the effects of multileaf collimator (MLC) leaf width on normal-brain-tissue doses and dose conformity of SRS RapidArc treatment plans for brain tumors. Methods: Ten patients with 24 intracranial tumors (seven with 1–2 and three with 4–6 lesions) were planned using RapidArc for both Varian Millennium 120 MLC (5 mm leaf width) and high definition (HD) MLC (2.5 mm leaf width). Between 2 and 8 arcs were used with two full coplanar arcs and the rest non-coplanar half arcs. 6 MV beams were used and plans were optimized with a high priority to the Normal Tissue Objective (to achieve dose conformity and sharp dose fall-off) and normal brain tissue. Calculation was done using AAA on a 1 mm grid size. The prescription dose ranged from 14–22 Gy. Plans were normalized such that 99% of the target received the prescription dose. Identical beam geometries, optimizations, calculations, and normalizations were used for both plans. Paddick Conformity Index (PCI), V4, V8 and V12 Gy for normal brain tissue and Integral Dose were used for analysis. Results: In all cases, HD MLC plans performed better in sparing normal brain tissue, achieving a higher PCI with a lower Integral Dose. The average PCI for all 24 targets was 0.75±0.23 and 0.70±0.23 (p ≤0.0015) for HD MLC and Millennium MLC plans, respectively. The average ratio of normal brain doses for Millennium MLC to HD MLC plans was 1.30±0.16, 1.27±0.15, and 1.31±0.18 for the V4, V8, and V12, respectively. The differences in normal brain dose for all criteria were statistically significant with p-value < 0.02. On average Millennium MLC plans had a 16% higher integral dose than HD MLC plans. Conclusion: Significantly better dose conformity with reduced volume of normal brain tissue and integral dose was achieved with HD MLC plans compared to Millennium MLC plans

  13. Area G perimeter surface-soil and single-stage water sampling: Environmental surveillance for fiscal year 95. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Childs, M.; Conrad, R.

    1997-09-01

    ESH-19 personnel collected soil and single-stage water samples around the perimeter of Area G at Los Alamos National Laboratory (LANL) during FY 95 to characterize possible radionuclide movement out of Area G through surface water and entrained sediment runoff. Soil samples were analyzed for tritium, total uranium, isotopic plutonium, americium-241, and cesium-137. The single-stage water samples were analyzed for tritium and plutonium isotopes. All radiochemical data was compared with analogous samples collected during FY 93 and 94 and reported in LA-12986 and LA-13165-PR. Six surface soils were also submitted for metal analyses. These data were included with similar data generated for soil samples collected during FY 94 and compared with metals in background samples collected at the Area G expansion area.

  14. [Study on pharmacognosy of Ginkgo leaf].

    Science.gov (United States)

    Geng, Guo-Ping; Ma, Zhi-Gang; Mao, Chong-Wu

    2007-05-01

    The primary study of Ginkgo leaf such as crude drug macroscopic and powder characteristics were carried out, and the flavonoids content in the leaf of Ginkgo in different areas of Gansu province was determined by HPLC, in order to provide scientific references for the exploitation of Ginkgo in Gansu province.

  15. Leaf Wetness within a Lily Canopy

    NARCIS (Netherlands)

    Jacobs, A.F.G.; Heusinkveld, B.G.; Klok, E.J.

    2005-01-01

    A wetness duration experiment was carried out within a lily field situated adjacent to coastal dunes in the Netherlands. A within-canopy model was applied to simulate leaf wetness in three layers, with equal leaf area indices, within the canopy. This simulation model is an extension of an existing

  16. A Constrained Maximization Model for inspecting the impact of leaf shape on optimal leaf size and stoma resistance

    Science.gov (United States)

    Ding, J.; Johnson, E. A.; Martin, Y. E.

    2017-12-01

    potential with respect to net leaf carbon gain. With same leaf area, total xylem resistance of narrow leaf is higher than broad leaf. Given same stoma resistance and petiole water potential, narrow leaf will lose more xylem water potential than broad leaf. Consequently, narrow leaf has smaller size and higher stoma resistance at optimum.

  17. Impact of Moringa oleifera lam. Leaf powder supplementation versus nutritional counseling on the body mass index and immune response of HIV patients on antiretroviral therapy: a single-blind randomized control trial.

    Science.gov (United States)

    Tshingani, Koy; Donnen, Philippe; Mukumbi, Henri; Duez, Pierre; Dramaix-Wilmet, Michèle

    2017-08-22

    To achieve effective antiretroviral therapy (ART) outcomes, adherence to an antiretroviral regimen and a good immunometabolic response are essential. Food insecurity can act as a real barrier to adherence to both of these factors. Many people living with human immunodeficiency virus (PLHIV) treated with ART in the Democratic Republic of the Congo (DRC) are faced with nutritional challenges. A significant proportion are affected by under nutrition, which frequently leads to therapeutic failure. Some HIV care facilities recommend supplementation with Moringa oleifera (M.O.) Lam. leaf powder to combat marginal and major nutritional deficiencies. This study aims to assess the impact of M.O. Lam. leaf powder supplementation compared to nutritional counseling on the nutritional and immune status of PLHIV treated with ART. A single-blind randomized control trial was carried out from May to September 2013 at an outpatient clinic for HIV-infected patients in Kinshasa (DRC). Sixty adult patients who were at stable HIV/AIDS clinical staging 2, 3 or 4 according to the World Health Organization (WHO), and were undergoing ART were recruited. After random allocation, 30 patients in the Moringa intervention group (MG) received the M.O. Lam. leaf powder daily over 6 months, and 30 in the control group (CG) received nutritional counseling over the same period. Changes in the body mass index (BMI) were measured monthly and biological parameters were measured upon admission and at the end of the study for the patients in both groups. The two study groups were similar in terms of long-term nutritional exposure, sociodemographic, socioeconomic, clinical, and biological features. At 6 months follow-up, patients in the MG exhibited a significantly greater increase in BMI and albumin levels than those in the CG. The interaction between the sociodemographic, clinical, and biological characteristics of patients in the two groups was not significant, with the exception of professional

  18. Phase 1 RCRA Facility Investigation and Corrective Measures Study Work Plan for Single Shell Tank Waste Management Areas

    International Nuclear Information System (INIS)

    ROGERS, P.M.

    2000-01-01

    This document is the master work plan for the Resource Conservation and Recovery Act of 1976 (RCRA) for single-shell tank (SST) farms at the Hanford Site. Evidence indicates that releases at four of the seven SST waste management areas have impacted

  19. Phase 1 RCRA Facility Investigation and Corrective Measures Study Work Plan for Single Shell Tank Waste Management Areas

    Energy Technology Data Exchange (ETDEWEB)

    ROGERS, P.M.

    2000-06-01

    This document is the master work plan for the Resource Conservation and Recovery Act of 1976 (RCRA) for single-shell tank (SST) farms at the Hanford Site. Evidence indicates that releases at four of the seven SST waste management areas have impacted.

  20. Sifting thourgh single grave settlements : Keinsmerbrug and Mienakker in the Noord Holland tidal area (the Netherlands)

    NARCIS (Netherlands)

    Kleijne, J.P.; Beckerman, Sandra; Brinkhuizen, Dick; Brinkkemper, O.; Garcia-Diaz, V.; Kubiak-Martens, L.; LAUWERIER, RCGM; Oudemans, T.F.M.; Peeters, Johannes; Raemaekers, Daniel; Smit, Bjorn; Theunissen, L.; van Gijn, A.L; Zeiler, J.T.; Furholt, Martin; Grossman, Ralph; Szmyt, Marzena

    2016-01-01

    Between 2009 and 2014, a research project was carried out by several research institutes and commercial companies in order to study and publish three settlement sites of the Single Grave Culture located in the Western Netherlands. These sites were excavated more than twenty years ago, but

  1. Comparison of high power large mode area and single mode 1908nm Tm-doped fiber lasers

    Science.gov (United States)

    Johnson, Benjamin R.; Creeden, Daniel; Limongelli, Julia; Pretorius, Herman; Blanchard, Jon; Setzler, Scott D.

    2016-03-01

    We compare large mode area (LMA) and single-mode (SM) double-clad fiber geometries for use in high power 1908nm fiber lasers. With a simple end-pumped architecture, we have generated 100W of 1908nm power with LMA fiber at 40% optical efficiency and 117W at 52.2% optical efficiency with single-mode fiber. We show the LMA fiber is capable of generating >200W and the SM fiber is capable of >300W at 1908nm. In all cases, the fiber lasers are monolithic power-oscillators with no free-space coupling.

  2. DETERMINATION OF A MATHEMATICAL MODEL TO ESTIMATE THE AREA AND DRY WEIGHT OF THE LEAF LIMBO OF Prunus persica CV. Jarillo DETERMINACIÓN DE UN MODELO MATEMÁTICO PARA LA ESTIMACIÓN DEL ÁREA FOLIAR Y PESO SECO DEL LIMBO DE Prunus persica CV. Jarillo

    Directory of Open Access Journals (Sweden)

    Enrique Quevedo García

    2012-06-01

    Full Text Available Abstract. A study was conducted to determine the variables that estimated the leaf limbo area and the leaf limbo dry weight of peach Prunus persica (L. Batsch cv. Jarillo. Fifty leaves, aged 2.5 months, were selected and measured: leaf limbo length and width, petiole length, leaf length, petiole diameter, leaf limbo fresh weight, petiole fresh weight, leaf fresh weight, leaf limbo dry weight, petiole dry weight, leaf dry weight, length/width limbo, petiole length/limbo length and leaf limbo area. The results allowed to obtain regression equations for estimating the leaf area and the limbo dry weight. Using the lineal models LA = b1 + b2 (LLL x LLW and LA= b1+ b2LLL + b3LLW a leaf area equation was determined. Alternative models to calculate limbo dry weight were evaluated LLDW = -b1+ b2 LLFW and LLDW= - b1 + b2LLL + b3PL. The best equations found with an R2 of 0.99 were LA = 1.572 + 0.65169(LLL x LLW, LA=-23.106+2.8064LLW + 3.6761LLL and LLDW = -0.002+0.401(LLFW.Resumen. Se realizó un estudio para determinar las variables que estimaran el área del limbo foliar y el peso seco del limbo de durazno Prunus persica (L. Batsch cv. Jarillo. Se seleccionaron cincuenta hojas con 2,5 meses de edad, fueron medidos: ancho del limbo, longitud del limbo, longitud del peciolo, longitud hoja, diámetro peciolo, peso fresco del limbo, peso fresco del peciolo, peso fresco de la hoja, peso seco del limbo, peso seco peciolo, peso seco de la hoja, longitud /ancho limbo, longitud del peciolo/longitud del limbo, área foliar del limbo. Los resultados alcanzados permitieron obtener ecuaciones de regresión para estimar el área foliar del limbo y el peso seco del limbo. Se halló una ecuación para la determinación del área foliar del limbo con los modelos lineales LA = b1 + b2 (LLL x LLW y LA= b1 + b2LLL + b3LLW. También se evaluaron modelos alternativas para calcular el peso seco del limbo, LLDW = -b1+ b2LLFW y LLDW= - b1 + b2LLL + b3PL. Las mejores ecuaciones

  3. Estimación del area de las hojas en plantas de trigo bajo diferentes tipos de estrés abiótico Leaf area estimation in wheat plants suffering several kinds of abiotic stress

    Directory of Open Access Journals (Sweden)

    D.H. Cogliatti

    2010-06-01

    Full Text Available En trigo, es posible estimar el área de las hojas (AF utilizando el producto del largo, el ancho de la lámina (LxA y un coeficiente de proporcionalidad (b m. Sin embargo, no hay información sobre la posibilidad de usar el mismo valor del coeficiente para estimar el área en plantas que sufren estrés hídrico, lumínico o nutricional. Para estudiar este punto se realizaron dos experimentos en los cuales se aplicó sequía, sombreo y deficiencias de N y P a plantas de trigo. El coeficiente b m se calculó a partir de la regresión lineal entre AF y LxA y fue similar entre las plantas control y aquellas que sufrieron sequía o deficiencias de N o P, pero fue distinto en plantas sombreadas. El mayor valor de b m en las plantas sombreadas se debió a una mayor proporción del sector medio de la lámina, definido por su forma rectangular. La validación de la posibilidad de usar el b m del control para estimar AF en plantas estresadas se realizó por regresión lineal entre el AF medida y calculada. Se concluye que puede usarse el mismo coeficiente b m para estimar el AF en plantas no estresadas y en plantas que sufren sequía o deficiencias de N o P. El uso del mismo valor del coeficiente b m en plantas sombreadas llevó a una subestimación del AF, la que fue más pronunciada a medida que aumentó el sombreo.In wheat, leaf area (LA can be estimated as the product between length, maximum blade width (LxW and a proportionality coefficient b m. However, it is unknown whether this coefficient is the same in stressed and non stressed plants. In order to study this, two experiments in which drought, shading and N and P deficiencies were applied to wheat plants were performed. The b m coefficient was calculated by linear regression between LA and LxW. The coefficient was similar in control plants as compared to those suffering wilting or N or P-deficiency, but different in shaded plants. The greater b m in shaded plants was due to an increased

  4. Area efficient digital logic NOT gate using single electron box (SEB

    Directory of Open Access Journals (Sweden)

    Bahrepour Davoud

    2017-01-01

    Full Text Available The continuing scaling down of complementary metal oxide semiconductor (CMOS has led researchers to build new devices with nano dimensions, whose behavior will be interpreted based on quantum mechanics. Single-electron devices (SEDs are promising candidates for future VLSI applications, due to their ultra small dimensions and lower power consumption. In most SED based digital logic designs, a single gate is introduced and its performance discussed. While in the SED based circuits the fan out of designed gate circuit should be considered and measured. In the other words, cascaded SED based designs must work properly so that the next stage(s should be driven by the previous stage. In this paper, previously NOT gate based on single electron box (SEB which is an important structure in SED technology, is reviewed in order to obtain correct operation in series connections. The correct operation of the NOT gate is investigated in a buffer circuit which uses two connected NOT gate in series. Then, for achieving better performance the designed buffer circuit is improved by the use of scaling process.

  5. Nutritional status and specific leaf area of mahogany and tonka bean under two light environments Estado nutricional e área foliar específica de mogno e cumaru sob dois ambientes de luz

    Directory of Open Access Journals (Sweden)

    José Francisco de C. Gonçalves

    2005-01-01

    Full Text Available Studies on nutritional status and leaf traits were carried out in two tropical tree species Swietenia macrophylla King (mahogany and Dipetryx odorata Aubl. Willd. (tonka bean planted under contrasting light environments in Presidente Figueiredo-AM, Brazil. Leaves of S. macrophylla and D. odorata were collected in three year-old trees grown under full sunlight (about 2000 µmol m-2 s-1 and natural shade under a closed canopy of Balsa-wood plantation (Ochroma pyramidale Cav. Ex. Lam.Urb about 260 µmol m-2 s-1. The parameters analysed were leaf area (LA, leaf dry mass (LDM, specific leaf area (SLA and leaf nutrient contents. It was observed that, S. macrophylla leaves grown under full sunlight showed LA 35% lower than those grown under shade. In D. odorata leaves these differences in LA were not observed. In addition, it was observed that S. macrophylla shade leaves, for LDM, were 50% smaller than sun leaves, while in D. odorata, there differences were not observed. SLA in S. macrophylla presented that sun leaves were three times smaller than those grown under shade. In D. odorata, no differences were observed. Nutrient contents in S. macrophylla, regardless of their light environments, showed higher contents for P and Ca than those found in D. odorata. The N, K, Fe and Mn contents in S. macrophylla leaves decreased under shade. Finally, we suggest that the decreasing in leaf nutrient contents may have a negative influence on leaf growth. The results demonstrated that the tested hypothesis is true for leaf traits, which D. odorata, late-successional species, showed lower plasticity for leaf traits than Swietenia macrophylla, mid-successional species.Estudou-se a nutrição mineral e as características foliares de duas espécies arbóreas tropicais Switenia macrophylla King (mogno e Dipteryx odorata Aubl Willd (cumaru plantadas sob dois ambientes de luz em Presidente Figueiredo - AM, Brasil. Folhas de S. macrophylla e de D. odorata, com três anos

  6. Índice de área foliar e produtividade do tomate sob condições de ambiente protegido Leaf area index and productivity of tomatoes under greenhouse conditions

    Directory of Open Access Journals (Sweden)

    Ligia S. Reis

    2013-04-01

    Full Text Available O cultivo de tomate tem-se expandido nos últimos anos em ambiente protegido, especialmente nas regiões Sul e Sudeste do Brasil, com o propósito de melhorar a produtividade e a qualidade dos produtos agrícolas, em razão de oferecer regularidade na produção. Objetivou-se, com o presente trabalho, determinar, ao longo do ciclo da cultura, a relação entre o índice de área foliar e a produtividade e, ao final do ciclo, os componentes de produção do tomateiro, em ambiente protegido. Os modelos foram gerados por meio de equações polinomiais de 1ª e 2ª ordem tendo-se, como variável independente, o número de dias após o transplantio. Constatou-se ser possível determinar, em ambiente protegido e por meio de modelo matemático, o índice de área foliar dessa olerícola considerando-se os dias após o transplantio. A partir de valores de índice de área foliar pode-se determinar a produtividade da cultura e o período da máxima produtividade auxiliando os agricultores a estimar a melhor época de semeadura e o transplante do tomateiro.The tomato cultivation in the greenhouse has been expanded in the last years, mainly, in the South and Southeast regions of Brazil, whose purpose is to improve the productivity and the quality of the agricultural products, offering regularity in the production. The present study aimed to determine, along the crop cycle, the relationship between the leaf area index and the productivity, and at the end of the cycle, the components of production of the tomato in the greenhouse. The models were generated through polynomial equations of 1st and 2nd order, having as independent variable the number of days after the transplanting. It was verified that it is possible to determine, in the greenhouse, through mathematical models, the leaf area index of the tomato crop considering the days after the transplanting. Basing on values of leaf area index, the productivity of the crop and the period of the maximum

  7. Single-grain Silicon Technology for Large Area X-ray Imaging

    NARCIS (Netherlands)

    Arslan, A.

    2015-01-01

    Digital flat panel X-ray imagers are currently using a-Si and poly-Si thin-film-transistors (TFTs). a-Si TFT permits the use of large area substrates, however, due to the amorphous nature, the carrier mobility is very low (<1 cm2/Vs). Poly-Si TFT improves the mobility (~150 cm2/Vs) but due to random

  8. Recharge Data Package for Hanford Single-Shell Tank Waste Management Areas

    Energy Technology Data Exchange (ETDEWEB)

    Fayer, Michael J.; Keller, Jason M.

    2007-09-24

    Pacific Northwest National Laboratory (PNNL) assists CH2M HILL Hanford Group, Inc., in its preparation of the Resource Conservation and Recovery Act (RCRA) Facility Investigation report. One of the PNNL tasks is to use existing information to estimate recharge rates for past and current conditions as well as future scenarios involving cleanup and closure of tank farms. The existing information includes recharge-relevant data collected during activities associated with a host of projects, including those of RCRA, the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), the CH2M HILL Tank Farm Vadose Zone Project, and the PNNL Remediation and Closure Science Project. As new information is published, the report contents can be updated. The objective of this data package was to use published data to provide recharge estimates for the scenarios being considered in the RCRA Facility Investigation. Recharge rates were estimated for areas that remain natural and undisturbed, areas where the vegetation has been disturbed, areas where both the vegetation and the soil have been disturbed, and areas that are engineered (e.g., surface barrier). The recharge estimates supplement the estimates provided by PNNL researchers in 2006 for the Hanford Site using additional field measurements and model analysis using weather data through 2006.

  9. Facile electrochemical transfer of large-area single crystal epitaxial graphene from Ir(1 1 1)

    DEFF Research Database (Denmark)

    Koefoed, Line; Kongsfelt, Mikkel; Ulstrup, Søren

    2015-01-01

    High-quality growth of graphene and subsequent reliable transfer to insulating substrates are needed for various technological applications, such as flexible screens and high speed electronics. In this paper, we present a new electrochemical method for the transfer of large-area, high-quality sin...

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

    Directory of Open Access Journals (Sweden)

    Renato Contillo

    2009-06-01

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

  11. Araneofauna of the leaf litter in two areas of restinga forest in Capão do Leão, Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Everton Nei Lopes Rodrigues

    2005-05-01

    Full Text Available The soil spider fauna of a restinga forest in Capão do Leão, Rio Grande do Sul, southern Brazil, was inventoried for a year. Samples were taken in the sandy restinga forest and in the ecotone, monthly, on two 30 m-long transects. Biological material was sampled with 30x30 cm quadrats, four for each transect and eight per monthly sample, with all leaf litter in the quadrats also being collected. Over the 12 samples, dry litter weighed 11.88 kg. Of a total of 96 quadrats, we calculated an annual average of 130.1 spiders/m2. The samples yielded 1124 individuals, of which 335 were adults and 788 were immature, distributed in 26 families with the highest representativity in the Oonopidae (19.57%, Lycosidae (18.06%, Theridiidae (17.08% and Salticidae (10.68% categories. Forty-four morphospecies were distinguished, the most abundant being Euryopis sp. (13.26% and Guaraniella sp. (12.8%. The month with the highest number of individuals was February 2001 (170 spiders and the one with the lowest number was July 2001 (37 specimens. Between the two transects, more spiders were found in the sandy restinga forest Araneofauna de serapilheira em mata de restinga (629 spiders than in the ecotone (495 individuals. The species richness index was 7.39 and the estimated species richness at 53.87 morphospecies.

  12. Spatial distribution of SPAD value and determination of the suitable leaf for N diagnosis in cucumber

    Science.gov (United States)

    Hu, Jing; Li, Chenxiao; Wen, Yifang; Gao, Xinhao; Shi, Feifei; Han, Luhua

    2018-01-01

    To determine the best leaf position for nitrogen diagnosis in cucumber with SPAD meter, greenhouse experiments were carried out to study spatial distribution of SPAD value of different position of the 3rd fully expanded cucumber leaf in the effect of different nitrogen levels, and the correlations between SPAD values and nitrogen concentration of chlorophyll. The results show that there is remarkable different SPAD value in different positions of the 3rd fully expanded leaf in the flowering and fruiting stage. Comparing the coefficients of SPAD value variation, we find that the coefficient of variation of leaf edge was significantly higher than the edge of the main vein, and the coefficient of variation of triangular area of leaf tip is significantly higher than any other leaf area. There is a significant correlation between SPAD values and leaf nitrogen content. Preliminary study shows that triangular area of leaf tip from the 20% leaf tip to leaf edge is the best position for nitrogen diagnosis.

  13. Effect of Wind on the Relation of Leaf N, P Stoichiometry with Leaf Morphology in Quercus Species

    Directory of Open Access Journals (Sweden)

    Peng Zhang

    2018-02-01

    Full Text Available Leaf nitrogen (N and phosphorus (P stoichiometry correlates closely to leaf morphology, which is strongly impacted by wind at multiple scales. However, it is not clear how leaf N, P stoichiometry and its relationship to leaf morphology changes with wind load. We determined the leaf N and P concentrations and leaf morphology—including specific leaf area (SLA and leaf dissection index (LDI—for eight Quercus species under a simulated wind load for seven months. Leaf N and P concentrations increased significantly under these conditions for Quercus acutissima, Quercus rubra, Quercus texana, and Quercus palustris—which have elliptic leaves—due to their higher N, P requirements and a resultant leaf biomass decrease, which is a tolerance strategy for Quercus species under a wind load. Leaf N:P was relatively stable under wind for all species, which supports stoichiometric homeostasis. Leaf N concentrations showed a positive correlation to SLA, leaf N and P concentrations showed positive correlations to LDI under each wind treatment, and the slope of correlations was not affected by wind, which indicates synchronous variations between leaf stoichiometry and leaf morphology under wind. However, the intercept of correlations was affected by wind, and leaf N and P use efficiency decreased under the wind load, which suggests that the Quercus species changes from “fast investment-return” in the control to “slow investment-return” under windy conditions. These results will be valuable to understanding functional strategies for plants under varying wind loads, especially synchronous variations in leaf traits along a wind gradient.

  14. RCRA Assessment Plan for Single-Shell Tank Waste Management Area TX-TY

    Energy Technology Data Exchange (ETDEWEB)

    Horton, Duane G.

    2007-03-26

    WMA TX-TY contains underground, single-shell tanks that were used to store liquid waste that contained chemicals and radionuclides. Most of the liquid has been removed, and the remaining waste is regulated under the RCRA as modi¬fied in 40 CFR Part 265, Subpart F and Washington State’s Hazardous Waste Management Act . WMA TX-TY was placed in assessment monitoring in 1993 because of elevated specific conductance. A groundwater quality assessment plan was written in 1993 describing the monitoring activities to be used in deciding whether WMA TX-TY had affected groundwater. That plan was updated in 2001 for continued RCRA groundwater quality assessment as required by 40 CFR 265.93 (d)(7). This document further updates the assessment plan for WMA TX-TY by including (1) information obtained from ten new wells installed at the WMA after 1999 and (2) information from routine quarterly groundwater monitoring during the last five years. Also, this plan describes activities for continuing the groundwater assessment at WMA TX TY.

  15. Caracterizacion de nueve genotipos de maiz (Zea mays L. en relacion a area foliar y coeficiente de extincion de luz Caracterização de nove genótipos de milho (Zea mays L. en relação à área foliar e coeficiente de extinção de luz Evaluation of nine corn (Zea mays L. genotypes in relation to leaf area and light extinction coefficient

    Directory of Open Access Journals (Sweden)

    R.G. Camacho

    1995-08-01

    .A field experiment was carried out to evaluate nine corn genotypes (Arichuna, Baraure, B raquitico, Expe-rimental-2, Foremaiz PB, FM-6, Obregón, Proseca-71 and Tocorón in relation to: mean leaf area per plant, total leaf area per plant (TLA, leaf area index (LAI, grain yield (Y and light extinction coefficient (K at 0.50m, 1.00m, 1.50m, 2.00m and 2.50m of plant height (from soil to flag leaf. Also, correlation and single regression between LAI and yield was performed. Significant genotypical differences for all variables were found, except for mean leaf area per plant Ranging was: mean leaf area per plant (471 cm² for Foremaiz PB and 606 cm² for Baraure; TLA (5,327 cm² for Foremaiz PB and 8,411 for Braquítico; LAI (4.26, Foremaiz PB and 6.67, Braquítico; K (0.23 for Braquítico and 0.42, Arichuna; Y (2, 877, Braquítico and 4,784 kg.ha-1 for Tocoron.The relationship between Y and LAI was not significant (r = 0.07. The relationship of LAI and K was described very well by Beer's law.

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

    Science.gov (United States)

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

    2017-12-01

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

  17. Relating Stomatal Conductance to Leaf Functional Traits.

    Science.gov (United States)

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

    2015-10-12

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

  18. SINGLE CHANNEL SEISMIC APPLICATION FOR GAS CHARGED SEDIMENT RECONNAISSANCE IN GEOHAZARD STUDY OF PORT CONSTRUCTION AT WETLAND AREA

    Directory of Open Access Journals (Sweden)

    Taufan Wiguna

    2016-10-01

    Full Text Available Gas charged sediment as a one of parameter for geohazard study in infrastructure especially in swamp area. Instability of sediment layer for exampel subsidence and landslide result in geohazard potention that caused by gas charged sediment. Seismic single channel can be used to identufy gas charged sediment location. Seabed morphology is collected from bathymetry and tidal survey. From seismic profile interpretation shows gas charged sediment indication in Line A and Line B. That indication emerged by presence of acoustic turbid zone and acoustic blanking. Line A and Line B location will be spotlight in next geotechnic port construction study.

  19. Medium area, flexible single and tandem junction solar cells based on roll coated semi-random copolymers

    DEFF Research Database (Denmark)

    Andersen, Thomas Rieks; Dam, Henrik Friis; Burkhart, Beate

    2014-01-01

    We report on medium area (1 cm2) slot-die coated organic photovoltaic devices (OPVs) of a recently developed semi-random copolymer of poly-3-hexylthiophene and diketopyrrolopyrrole (P3HTT–DPP- 10%) mixed with phenyl-C61-butyric acid methyl ester ([60]PCBM). The devices were prepared using a compact...... laboratory roll-coater using only slot-die coating and flexographic printing under ambient conditions on a flexible ITO-free substrate. In order to overcome a low JSC and FF obtained for single junction devices, devices were also prepared in a tandem geometry making it possible to employ thinner junction...

  20. Combate sistemático de formigas-cortadeiras com iscas granuladas, em eucaliptais com cultivo mínimo Systematic control of leaf-cutting ants in areas with eucalyptus stands under minimum cultivation system

    Directory of Open Access Journals (Sweden)

    Ronald Zanetti

    2003-06-01

    Full Text Available Avaliou-se a eficiência do combate sistemático de formigas-cortadeiras em áreas de reforma de eucalipto com cultivo mínimo, na Celulose Nipo-Brasileira S.A., em Belo Oriente, Minas Gerais, de setembro a dezembro de 1996. Os tratamentos consistiram na aplicação de uma isca granulada com sulfluramida (0,3% de forma sistemática, a granel ou com microporta-iscas, na dosagem de 5 g a cada 6 m² e 10 g a cada 12 m², respectivamente. A mortalidade das colônias de formigas-cortadeiras foi avaliada 30 dias após a aplicação da isca. Foram encontradas até 396,3, 285,2, 59,3, 55,6, 29,6 e 14,8 colônias de Mycocepurus goeldii, Sericomyrmex sp., Acromyrmex subterraneus molestans, Atta spp., Acromyrmex balzani e Acromyrmex niger (Hymenoptera: Formicidae por hectare, respectivamente. A eficiência da isca granulada no combate sistemático variou com o método empregado e com a espécie de formiga-cortadeira. A maior eficiência foi obtida para A. subterraneus molestans, com 69,2% de suas colônias mortas com a isca aplicada a granel e 62,5% com microporta-iscas, o que indica que a distribuição entre dois pontos com isca nos plantios de eucalipto foi maior que a área de forrageamento das formigas-cortadeiras encontradas e, ou, que a dosagem aplicada por ponto foi insuficiente.The efficiency of a systematic application of baits against leaf-cutting ants was evaluated in a eucalypus plantation under a minimum cultivation system, in areas owned by Celulose Nipo-Brasileira S.A. (CENIBRA, in Belo Oriente, Minas Gerais, Brazil, from September to December 1996. Treatments consisted of applying a granulated bait with sulfluramide (0.3% in a systematic manner in bulk and plastic bags at a dose of five grams every 6 m² (T1 and 10 grams at each 12 m² (T2. Mortality of colonies of leaf-cutting ants was evaluated 30 days after bait application. A. maximum of 396.3; 285.2; 59.3; 55.6; 29.6 and 14.8 colonies of Mycocepurus goeldii, Sericomyrmex sp

  1. Leaf traits and associated ecosystem characteristics across subtropical and timberline forests in the Gongga Mountains, Eastern Tibetan Plateau

    Science.gov (United States)

    Tianxiang Luo; Ji Luo; Yude Pan

    2005-01-01

    Knowledge of how leaf characteristics might be used to deduce information on ecosystem functioning and how this scaling task could be done is limited. In this study, we present field data for leaf lifespan, specific leaf area (SLA) and mass and area-based leaf nitrogen concentrations (Nmass, Narea) of dominant tree species...

  2. Leaf area of common bean genotypes during early pod filling as related to plant adaptation to limited phosphorus supply Área foliar de genótipos de feijoeiro no início de enchimento de vagens e sua relação com a adaptação vegetal ao suprimento limitado de fósforo

    Directory of Open Access Journals (Sweden)

    Roberto Santos Trindade

    2010-02-01

    Full Text Available Low phosphorus supply markedly limits leaf growth and genotypes able to maintain adequate leaf area at low P could adapt better to limited-P conditions. This work aimed to investigate the relationship between leaf area production of common bean (Phaseolus vulgaris genotypes during early pod filling and plant adaptation to limited P supply. Twenty-four genotypes, comprised of the four growth habits in the species and two weedy accessions, were grown at two P level applied to the soil (20 and 80 mg kg-1 in 4 kg pots and harvested at two growth stages (pod setting and early pod filling. High P level markedly increased the leaf number and leaf size (leaf area per leaf, slightly increased specific leaf area but did not affect the net assimilation rate. At low P level most genotypic variation for plant dry mass was associated with leaf size, whereas at high P level this variation was associated primarily with the number of leaves and secondarily with leaf size, specific leaf area playing a minor role at both P level. Determinate bush genotypes presented a smaller leaf area, fewer but larger leaves with higher specific leaf area and lower net assimilation rate. Climbing genotypes showed numerous leaves, smaller and thicker leaves with a higher net assimilation rate. Indeterminate bush and indeterminate prostrate genotypes presented the highest leaf area, achieved through intermediate leaf number, leaf size and specific leaf area. The latter groups were better adapted to limited P. It is concluded that improved growth at low P during early pod filling was associated with common bean genotypes able to maintain leaf expansion through leaves with greater individual leaf area.O baixo suprimento de P limita acentuadamente o crescimento foliar, e genótipos capazes de manter adequada área foliar sob baixo P podem adaptar-se melhor a condições de limitação do nutriente. Este trabalho teve por objetivo investigar as relações entre a produção de

  3. Automated estimation of leaf distribution for individual trees based on TLS point clouds

    Science.gov (United States)

    Koma, Zsófia; Rutzinger, Martin; Bremer, Magnus

    2017-04-01

    Light Detection and Ranging (LiDAR) especially the ground based LiDAR (Terrestrial Laser Scanning - TLS) is an operational used and widely available measurement tool supporting forest inventory updating and research in forest ecology. High resolution point clouds from TLS already represent single leaves which can be used for a more precise estimation of Leaf Area Index (LAI) and for higher accurate biomass estimation. However, currently the methodology for extracting single leafs from the unclassified point clouds for individual trees is still missing. The aim of this study is to present a novel segmentation approach in order to extract single leaves and derive features related to leaf morphology (such as area, slope, length and width) of each single leaf from TLS point cloud data. For the study two exemplary single trees were scanned in leaf-on condition on the university campus of Innsbruck during calm wind conditions. A northern red oak (Quercus rubra) was scanned by a discrete return recording Optech ILRIS-3D TLS scanner and a tulip tree (Liliodendron tulpifera) with Riegl VZ-6000 scanner. During the scanning campaign a reference dataset was measured parallel to scanning. In this case 230 leaves were randomly collected around the lower branches of the tree and photos were taken. The developed workflow steps were the following: in the first step normal vectors and eigenvalues were calculated based on the user specified neighborhood. Then using the direction of the largest eigenvalue outliers i.e. ghost points were removed. After that region growing segmentation based on the curvature and angles between normal vectors was applied on the filtered point cloud. On each segment a RANSAC plane fitting algorithm was applied in order to extract the segment based normal vectors. Using the related features of the calculated segments the stem and branches were labeled as non-leaf and other segments were classified as leaf. The validation of the different segmentation

  4. Leaf wetness distribution within a potato crop

    Science.gov (United States)

    Heusinkveld, B. G.

    2010-07-01

    The Netherlands has a mild maritime climate and therefore the major interest in leaf wetness is associated with foliar plant diseases. During moist micrometeorological conditions (i.e. dew, fog, rain), foliar fungal diseases may develop quickly and thereby destroy a crop quickly. Potato crop monocultures covering several hectares are especially vulnerable to such diseases. Therefore understanding and predicting leaf wetness in potato crops is crucial in crop disease control strategies. A field experiment was carried out in a large homogeneous potato crop in the Netherlands during the growing season of 2008. Two innovative sensor networks were installed as a 3 by 3 grid at 3 heights covering an area of about 2 hectares within two larger potato crops. One crop was located on a sandy soil and one crop on a sandy peat soil. In most cases leaf wetting starts in the top layer and then progresses downward. Leaf drying takes place in the same order after sunrise. A canopy dew simulation model was applied to simulate spatial leaf wetness distribution. The dew model is based on an energy balance model. The model can be run using information on the above-canopy wind speed, air temperature, humidity, net radiation and within canopy air temperature, humidity and soil moisture content and temperature conditions. Rainfall was accounted for by applying an interception model. The results of the dew model agreed well with the leaf wetness sensors if all local conditions were considered. The measurements show that the spatial correlation of leaf wetness decreases downward.

  5. Study of Cotton Leaf Senescence Induced by Alternaria alternata Infection.

    Science.gov (United States)

    Liu, Wei; Zhang, Wenwei; Zheng, Na; Zhai, Weibo; Qi, Fangjun

    2018-01-01

    Premature leaf senescence in cotton, which often happens during the mid to late growth period, has been occurring with an increasing frequency in many cotton-growing areas and causing serious reduction in yield and quality. One of the key factors causing cotton leaf senescence is the infection of Alternaria leaf spot pathogens (Alternaria species), which often happens when cotton plants encounter adverse environmental conditions, such as chilling stress and physiological impairment. Stressed cotton leaves are apt to be infected by Alternaria leaf spot pathogens (Alternaria alternata) because of the reduction in disease resistance, leading to the initiation of leaf senescence. Here we describe the induction of cotton leaf senescence by Alternaria alternata infection, including the evaluation of the disease index and measure of physiological impairment associated with cotton leaf senescence and analysis of possible molecular mechanism using microarray.

  6. Expanding our understanding of leaf functional syndromes in savanna systems: the role of plant growth form.

    Science.gov (United States)

    Rossatto, Davi Rodrigo; Franco, Augusto Cesar

    2017-04-01

    The assessment of leaf strategies has been a common theme in ecology, especially where multiple sources of environmental constraints (fire, seasonal drought, nutrient-poor soils) impose a strong selection pressure towards leaf functional diversity, leading to inevitable tradeoffs among leaf traits, and ultimately to niche segregation among coexisting species. As diversification on leaf functional strategies is dependent on integration at whole plant level, we hypothesized that regardless of phylogenetic relatedness, leaf trait functional syndromes in a multivariate space would be associated with the type of growth form. We measured traits related to leaf gas exchange, structure and nutrient status in 57 coexisting species encompassing all Angiosperms major clades, in a wide array of plant morphologies (trees, shrubs, sub-shrubs, herbs, grasses and palms) in a savanna of Central Brazil. Growth forms differed in mean values for the studied functional leaf traits. We extracted 4 groups of functional typologies: grasses (elevated leaf dark respiration, light-saturated photosynthesis on a leaf mass and area basis, lower values of leaf Ca and Mg), herbs (high values of SLA, leaf N and leaf Fe), palms (high values of stomatal conductance, leaf transpiration and leaf K) and woody eudicots (sub-shrubs, shrubs and trees; low SLA and high leaf Ca and Mg). Despite the large range of variation among species for each individual trait and the independent evolutionary trajectory of individual species, growth forms were strongly associated with particular leaf trait combinations, suggesting clear evolutionary constraints on leaf function for morphologically similar species in savanna ecosystems.

  7. Long-range projection neurons of the mouse ventral tegmental area: a single-cell axon tracing analysis.

    Science.gov (United States)

    Aransay, Ana; Rodríguez-López, Claudia; García-Amado, María; Clascá, Francisco; Prensa, Lucía

    2015-01-01

    Pathways arising from the ventral tegmental area (VTA) release dopamine and other neurotransmitters during the expectation and achievement of reward, and are regarded as central links of the brain networks that create drive, pleasure, and addiction. While the global pattern of VTA projections is well-known, the actual axonal wiring of individual VTA neurons had never been investigated. Here, we labeled and analyzed the axons of 30 VTA single neurons by means of single-cell transfection with the Sindbis-pal-eGFP vector in mice. These observations were complemented with those obtained by labeling the axons of small populations of VTA cells with iontophoretic microdeposits of biotinylated dextran amine. In the single-cell labeling experiments, each entire axonal tree was reconstructed from serial sections, the length of terminal axonal arbors was estimated by stereology, and the dopaminergic phenotype was tested by double-labeling for tyrosine hydroxylase immunofluorescence. We observed two main, markedly different VTA cell morphologies: neurons with a single main axon targeting only forebrain structures (FPN cells), and neurons with multibranched axons targeting both the forebrain and the brainstem (F + BSPN cells). Dopaminergic phenotype was observed in FPN cells. Moreover, four "subtypes" could be distinguished among the FPN cells based on their projection targets: (1) "Mesocorticolimbic" FPN projecting to both neocortex and basal forebrain; (2) "Mesocortical" FPN innervating the neocortex almost exclusively; (3) "Mesolimbic" FPN projecting to the basal forebrain, accumbens and caudateputamen; and (4) "Mesostriatal" FPN targeting only the caudateputamen. While the F + BSPN cells were scattered within VTA, the mesolimbic neurons were abundant in the paranigral nucleus. The observed diversity in wiring architectures is consistent with the notion that different VTA cell subpopulations modulate the activity of specific sets of prosencephalic and brainstem structures.

  8. Genome-Wide Association Mapping of Leaf Rust Response in a Durum Wheat Worldwide Germplasm Collection.

    Science.gov (United States)

    Aoun, Meriem; Breiland, Matthew; Kathryn Turner, M; Loladze, Alexander; Chao, Shiaoman; Xu, Steven S; Ammar, Karim; Anderson, James A; Kolmer, James A; Acevedo, Maricelis

    2016-11-01

    Leaf rust (caused by Erikss. []) is increasingly impacting durum wheat ( L. var. ) production with the recent appearance of races with virulence to widely grown cultivars in many durum producing areas worldwide. A highly virulent race on durum wheat was recently detected in Kansas. This race may spread to the northern Great Plains, where most of the US durum wheat is produced. The objective of this study was to identify sources of resistance to several races from the United States and Mexico at seedling stage in the greenhouse and at adult stage in field experiments. Genome-wide association study (GWAS) was used to identify single-nucleotide polymorphism (SNP) markers associated with leaf rust response in a worldwide durum wheat collection of 496 accessions. Thirteen accessions were resistant across all experiments. Association mapping revealed 88 significant SNPs associated with leaf rust response. Of these, 33 SNPs were located on chromosomes 2A and 2B, and 55 SNPs were distributed across all other chromosomes except for 1B and 7B. Twenty markers were associated with leaf rust response at seedling stage, while 68 markers were associated with leaf rust response at adult plant stage. The current study identified a total of 14 previously uncharacterized loci associated with leaf rust response in durum wheat. The discovery of these loci through association mapping (AM) is a significant step in identifying useful sources of resistance that can be used to broaden the relatively narrow leaf rust resistance spectrum in durum wheat germplasm. Copyright © 2016 Crop Science Society of America.

  9. Necessidades hídricas de citros e macieiras a partir da área foliar e da energia solar Water requirements of citrus and apple trees as affected by leaf area and solar energy

    Directory of Open Access Journals (Sweden)

    André Belmont Pereira

    2009-09-01

    Full Text Available A energia solar é a fonte primária para a fotossíntese e a transpiração vegetal para que uma cultura expresse seu potencial produtivo em um dado local. O método proposto neste estudo pretende facilitar o cálculo do volume de água (litros/planta/dia necessário para uma irrigação localizada com o mínimo desperdício possível em pomares cítricos e de macieiras, utilizando-se de dados usualmente disponíveis, tais como área foliar, densidade de fluxo de radiação solar global, saldo de radiação e déficit de saturação de vapor médio diário do ar. Considerando-se que a irrigação localizada consome bem menos água do que o sistema de aspersão, e que a outorga de água para irrigação está cada vez mais limitada, tal estudo vem a ser certamente de grande importância para assegurar a autossustentabilidade da agricultura irrigada, especialmente em regiões áridas e semiáridas. Foram utilizados neste trabalho, para desenvolvimento da metodologia proposta, dados de fluxo de seiva medidos através do método de fluxo de calor, em pomar de lima-ácida-Tahiti com área foliar de 48 e 99 m², bem como em pomar de macieiras com área foliar aproximada de 5; 8; 9; 11; 16 e 21 m². Os resultados obtidos indicaram que a metodologia proposta, baseada na habilidade das plantas em converter energia solar fixada em água transpirada, mostrou-se viável para avaliar a lâmina de irrigação de plantas cítricas e macieiras nas localidades estudadas.Solar energy is the primary source for photosynthesis and transpiration in such a way as to assure the expression of the crop yield potential at a given site. The current methodology aims to ease the calculation of the water amount (liters/plant/day necessary for a localized irrigation scheduling with a minimal loss possible at both citrus and apple trees orchards by means of usual available data, such as leaf area, global solar radiation flux density, net radiation and air daily mean steam

  10. Ajuste do modelo fototérmico de estimativa do desenvolvimento e do índice de área foliar de soja Adjustment of the photothermic model to estimate soybean development and leaf area index

    Directory of Open Access Journals (Sweden)

    Neila T. Toledo

    2010-03-01

    Full Text Available Visou-se neste estudo, realizar o ajuste do modelo de estimativa do desenvolvimento de populações de soja e da variação do índice de área foliar para a variedade IAS 5. Como fonte de variação na velocidade de desenvolvimento, diferentes épocas de plantio foram utilizadas em experimentos nos anos agrícolas de 2004/2005 (três datas e 2005/2006 (quatro datas no IRDeR (Instituto Regional de Desenvolvimento Rural localizado em Augusto Pestana, RS (28º 27' 17" S e 53º 54' 50" W, nos quais foram identificadas as datas em que ocorreram as principais fases do desenvolvimento da cultura da soja, seguindo a Escala Fenológica de Fehr & Caviness e estimados o índice de área foliar em quatro momentos: no final do período de instalação da população vegetal (V6; no início do florescimento (R1; início do enchimento de grãos (R5; e no início da maturação (R7. As variáveis meteorológicas temperaturas mínima e máxima diárias foram coletadas. Após o ajuste dos coeficientes genéticos, o modelo foi formatado no programa Stella 5.0. O modelo de estimativa do desenvolvimento da soja teve desempenho satisfatório, apresentando estimativas precisas para os dados que o determinaram. O modelo de estimativa do índice de área foliar apresentou estimativas satisfatórias.The present study was carried out to adjust the soy population development model and the leaf area index model for the IAS 5 cultivar. Different sowing dates were used in two experiments as source of development variation during 2004/2005 (three dates and 2005/2006 (four dates in the IRDeR (Instituto Regional de Desenvolvimento Rural located in Augusto Pestana, in the State of Rio Grande do Sul (28º 27' 17" S and 53º 54' 50" W. The main crop development phases were identified according to the Feher & Caviness phenological scale, and the leaf area index was determined in four occasions: at the final period of plant population installation (V6; at the beginning of flowering

  11. Initial steps toward the realization of large area arrays of single photon counting pixels based on polycrystalline silicon TFTs

    Science.gov (United States)

    Liang, Albert K.; Koniczek, Martin; Antonuk, Larry E.; El-Mohri, Youcef; Zhao, Qihua; Jiang, Hao; Street, Robert A.; Lu, Jeng Ping

    2014-03-01

    The thin-film semiconductor processing methods that enabled creation of inexpensive liquid crystal displays based on amorphous silicon transistors for cell phones and televisions, as well as desktop, laptop and mobile computers, also facilitated the development of devices that have become ubiquitous in medical x-ray imaging environments. These devices, called active matrix flat-panel imagers (AMFPIs), measure the integrated signal generated by incident X rays and offer detection areas as large as ~43×43 cm2. In recent years, there has been growing interest in medical x-ray imagers that record information from X ray photons on an individual basis. However, such photon counting devices have generally been based on crystalline silicon, a material not inherently suited to the cost-effective manufacture of monolithic devices of a size comparable to that of AMFPIs. Motivated by these considerations, we have developed an initial set of small area prototype arrays using thin-film processing methods and polycrystalline silicon transistors. These prototypes were developed in the spirit of exploring the possibility of creating large area arrays offering single photon counting capabilities and, to our knowledge, are the first photon counting arrays fabricated using thin film techniques. In this paper, the architecture of the prototype pixels is presented and considerations that influenced the design of the pixel circuits, including amplifier noise, TFT performance variations, and minimum feature size, are discussed.

  12. Evolutionarily significant units of the critically endangered leaf frog Pithecopus ayeaye (Anura, Phyllomedusidae) are not effectively preserved by the Brazilian protected areas network.

    Science.gov (United States)

    de Magalhães, Rafael Félix; Lemes, Priscila; Camargo, Arley; Oliveira, Ubirajara; Brandão, Reuber Albuquerque; Thomassen, Hans; Garcia, Paulo Christiano de Anchietta; Leite, Felipe Sá Fortes; Santos, Fabrício Rodrigues

    2017-11-01

    Protected areas (PAs) are essential for biodiversity conservation, but their coverage is considered inefficient for the preservation of all species. Many species are subdivided into evolutionarily significant units (ESUs) and the effectiveness of PAs in protecting them needs to be investigated. We evaluated the usefulness of the Brazilian PAs network in protecting ESUs of the critically endangered Pithecopus ayeaye through ongoing climate change. This species occurs in a threatened mountaintop ecosystem known as campos rupestres . We used multilocus DNA sequences to delimit geographic clusters, which were further validated as ESUs with a coalescent approach. Ecological niche modeling was used to estimate spatial changes in ESUs' potential distributions, and a gap analysis was carried out to evaluate the effectiveness of the Brazilian PAs network to protect P. ayeaye in the face of climate changes. We tested the niche overlap between ESUs to gain insights for potential management alternatives for the species. Pithecopus ayeaye contains at least three ESUs isolated in distinct mountain regions, and one of them is not protected by any PA. There are no climatic niche differences between the units, and only 4% of the suitable potential area of the species is protected in present and future projections. The current PAs are not effective in preserving the intraspecific diversity of P. ayeaye in its present and future range distributions. The genetic structure of P. ayeaye could represent a typical pattern in campos rupestres endemics, which should be considered for evaluating its conservation status.

  13. Seagrass leaf element content

    NARCIS (Netherlands)

    Vonk, J.A.; Smulders, Fee O.H.; Christianen, Marjolijn J.A.; Govers, Laura L.

    2017-01-01

    Knowledge on the role of seagrass leaf elements and in particular micronutrients and their ranges is limited. We present a global database, consisting of 1126 unique leaf values for ten elements, obtained from literature and unpublished data, spanning 25 different seagrass species from 28 countries.

  14. Leaf Size in Swietenia

    Science.gov (United States)

    Charles B. Briscoe; F. Bruce. Lamb

    1962-01-01

    A study was made of the putative hybrid of bigleaf and small-leaf mahoganies. Initial measurements indicated that bigleaf mahogany can be distinguished from small-leaf mahogany by gross measurements of leaflets. Isolated mother trees yield typical progeny. Typical mother trees in mixed stands yield like progeny plus, usually, mediumleaf progeny. Mediumleaf mother trees...

  15. How do leaf veins influence the worldwide leaf economic spectrum? Review and synthesis.

    Science.gov (United States)

    Sack, Lawren; Scoffoni, Christine; John, Grace P; Poorter, Hendrik; Mason, Chase M; Mendez-Alonzo, Rodrigo; Donovan, Lisa A

    2013-10-01

    Leaf vein traits are implicated in the determination of gas exchange rates and plant performance. These traits are increasingly considered as causal factors affecting the 'leaf economic spectrum' (LES), which includes the light-saturated rate of photosynthesis, dark respiration, foliar nitrogen concentration, leaf dry mass per area (LMA) and leaf longevity. This article reviews the support for two contrasting hypotheses regarding a key vein trait, vein length per unit leaf area (VLA). Recently, Blonder et al. (2011, 2013) proposed that vein traits, including VLA, can be described as the 'origin' of the LES by structurally determining LMA and leaf thickness, and thereby vein traits would predict LES traits according to specific equations. Careful re-examination of leaf anatomy, published datasets, and a newly compiled global database for diverse species did not support the 'vein origin' hypothesis, and moreover showed that the apparent power of those equations to predict LES traits arose from circularity. This review provides a 'flux trait network' hypothesis for the effects of vein traits on the LES and on plant performance, based on a synthesis of the previous literature. According to this hypothesis, VLA, while virtually independent of LMA, strongly influences hydraulic conductance, and thus stomatal conductance and photosynthetic rate. We also review (i) the specific physiological roles of VLA; (ii) the role of leaf major veins in influencing LES traits; and (iii) the role of VLA in determining photosynthetic rate per leaf dry mass and plant relative growth rate. A clear understanding of leaf vein traits provides a new perspective on plant function independently of the LES and can enhance the ability to explain and predict whole plant performance under dynamic conditions, with applications towards breeding improved crop varieties.

  16. Efeito do número de ramos produtivos sobre o desenvolvimento da área foliar e produtividade da figueira Effect of the number of productive branches on the leaf area development and fig tree yield

    Directory of Open Access Journals (Sweden)

    Luiz Carlos Santos Caetano

    2005-12-01

    Full Text Available O objetivo deste trabalho foi estudar o efeito do número de ramos produtivos sobre o desenvolvimento da área foliar e produtividade de figos verdes do cultivar Roxo de Valinhos. O experimento utilizando plantas de seis anos de idade, foi conduzido de novembro de 2002 a abril de 2003 na Pesagro-RJ, em Campos dos Goytacazes-RJ (21º19'23" de latitude sul, 41º19'40" de longitude oeste, altitude de 20 a 30 m e clima tipo Aw Köppen. Os tratamentos consistiram de plantas conduzidas com 16; 20; 24; 28 e 32 ramos. Utilizou-se do delineamento experimental de blocos ao acaso e cinco repetições. O IAF aumentou linearmente em função do número de ramos produtivos, enquanto a produtividade mostrou um modelo de resposta quadrática aos tratamentos, provavelmente, limitada pelo sombreamento no interior do dossel que reduz a formação de gemas frutíferas. A maior produtividade observada de figos verdes foi obtida quando as plantas foram conduzidas com 24 ramos, sendo que, neste tratamento, a área foliar média de cada planta foi de 6,2 m².The objective of the present work was to study the effect of number of productive branches on the leaf area development and green fig tree yield of Roxo de Valinhos cultivar. The experiment using six year-old plants was carried out between November/2002 and April/2003 at Pesagro-RJ, Campos dos Goytacazes, RJ (21º19'23" South latitude, 41º19'40", West longitude, altitude of 20 a 30 m and Aw Koppen climate. The treatments consisted of plants conducted with 16, 20, 24, 28 and 32 productive branches in a randomized block design with five replicates. The LAI incresead linearly in function of productive branches, whereas the yield showed a quadratic response pattern to the treatments, probably, limited by shading in canopy that decrease the fruit bud formation. The highest green fig yield was observed in the treatment which had plants conducted with twenty four branches, where the mean leaf area was 6,2 m².

  17. Leaf morphology shift linked to climate change.

    Science.gov (United States)

    Guerin, Greg R; Wen, Haixia; Lowe, Andrew J

    2012-10-23

    Climate change is driving adaptive shifts within species, but research on plants has been focused on phenology. Leaf morphology has demonstrated links with climate and varies within species along climate gradients. We predicted that, given within-species variation along a climate gradient, a morphological shift should have occurred over time due to climate change. We tested this prediction, taking advantage of latitudinal and altitudinal variations within the Adelaide Geosyncline region, South Australia, historical herbarium specimens (n = 255) and field sampling (n = 274). Leaf width in the study taxon, Dodonaea viscosa subsp. angustissima, was negatively correlated with latitude regionally, and leaf area was negatively correlated with altitude locally. Analysis of herbarium specimens revealed a 2 mm decrease in leaf width (total range 1-9 mm) over 127 years across the region. The results are consistent with a morphological response to contemporary climate change. We conclude that leaf width is linked to maximum temperature regionally (latitude gradient) and leaf area to minimum temperature locally (altitude gradient). These data indicate a morphological shift consistent with a direct response to climate change and could inform provenance selection for restoration with further investigation of the genetic basis and adaptive significance of observed variation.

  18. Mapping mangrove leaf area index at the species level using IKONOS and LAI-2000 sensors for the Agua Brava Lagoon, Mexican Pacific

    Science.gov (United States)

    Kovacs, John M.; Wang, Jinfei; Flores-Verdugo, Francisco

    2005-01-01

    Using both IKONOS and in situ LAI-2000 sensor data, a map of estimated LAI, based on NDVI, was created for the Agua Brava Lagoon, Mexican Pacific. The LAI values were then aggregated according to four classes; red mangrove ( Rhizophora mangle), healthy white mangrove ( Laguncularia racemosa), poor condition white mangrove and dead mangrove. Of the live mangrove, calculated at approximately 85% of the forest, mean LAI values of 2.49, 1.74 and 0.85 were determined for the red, healthy white and poor condition white mangrove, respectively. Excluding the dead areas, an overall estimated mangrove LAI value of 1.81 was ascertained for the 71 km 2 of mapped mangrove forest. Although the results do suggest the technique as a very rapid and effective method for monitoring the condition of mangroves at the species level, potential limitations are also discussed.

  19. Leaf area index estimation in a pine plantation with LAI-2000 under direct sunlight conditions: relationship with inventory and hydrologic variables

    International Nuclear Information System (INIS)

    Molina, A.; Campo, A. D. del

    2011-01-01

    LAI is a key factor in light and rainfall interception processes in forest stands and, for this reason, is called to play an important role in global change adaptive silviculture. Therefore, it is necessary to develop practical and operative methodologies to measure this parameter as well as simple relationships with other silviculture variables. This work has studied 1) the feasibility of LAI-2000 sensor in estimating LAI-stand when readings are taken under direct sunlight conditions; and 2) the ability of LAI in studying rainfall partitioned into throughfall (T) in an Aleppo pine stand after different thinning intensities, as well as its relationships to basal area, (G), cover (FCC), and tree density (D). Results showed that the angular correction scheme applied to LAI-2000 direct-sunlight readings stabilized them for different solar angles, allowing a better operational use of LAI-2000 in Mediterranean areas, where uniform overcast conditions are difficult to meet and predict. Forest cover showed the highest predictive ability of LAI (R 2 = 0.98; S = 0.28), then G (R 2 = 0.96; S = 0.43) and D (R 2 = 0.50; S = 0.28). In the hydrological plane, T increased with thinning intensity, being G the most explanatory variable (R 2 = 0.81; S = 3.07) and LAI the one that showed the poorest relation with it (R 2 = 0.69; S = 3.95). These results open a way for forest hydrologic modeling taking LAI as an input variable either estimated form LAI-2000 or deducted from inventory data. (Author) 36 refs.

  20. Strategies of leaf expansion in Ficus carica under semiarid conditions.

    Science.gov (United States)

    González-Rodríguez, A M; Peters, J

    2010-05-01

    Leaf area expansion, thickness and inclination, gas exchange parameters and relative chlorophyll content were analysed in field-grown fig (Ficus carica L.) leaves over time, from emergence until after full leaf expansion (FLE). Ficus carica leaves showed a subtle change in shape during the early stages of development, and FLE was reached within ca. 30 days after emergence. Changes in leaf thickness and inclination after FLE demonstrated good adaptation to environmental conditions during summer in areas with a Mediterranean climate. Changes in gas exchange parameters and relative chlorophyll content showed that F. carica is a delayed-greening species, reaching maximum values 20 days after FLE. Correlation analysis of datasets collected during leaf expansion, confirmed dependence among structural and functional traits in F. carica. Pn was directly correlated with stomatal conductance (Gs), transpiration (E), leaf area (LA) and relative chlorophyll content up to FLE. The effect of pruning on leaf expansion, a cultural technique commonly applied in this fruit tree, was also evaluated. Although leaf development in pruned branches gave a significantly higher relative leaf area growth rate (RGR(l)) and higher LA than non-pruned branches, no significant differences were found in other morphological and physiological traits, indicating no pruning effect on leaf development. All studied morphological and physiological characteristics indicate that F. carica is well adapted to semiarid conditions. The delayed greening strategy of this species is discussed.

  1. Brain areas involved in acupuncture needling sensation of de qi: a single-photon emission computed tomography (SPECT) study.

    Science.gov (United States)

    Chen, Jia-Rong; Li, Gan-Long; Zhang, Gui-Feng; Huang, Yong; Wang, Shu-Xia; Lu, Na

    2012-12-01

    De qi is a sensory response elicited by acupuncture stimulation. According to traditional Chinese medicine (TCM), de qi is essential for clinical efficacy. However, the understanding of the neurobiological basis of de qi is still limited. To investigate the relationship between brain activation and de qi by taking a single-photon emission computed tomography (SPECT) scan while applying acupuncture at TE5. A total of 24 volunteers were randomly divided into 4 groups, and received verum or sham acupuncture at true acupuncture point TE5 or a nearby sham point according to grouping. All subjects then received a (99m)Tc-ethylcysteinate dimer (ECD) SPECT scan. All six subjects in the verum acupuncture at true acupuncture point group experienced de qi sensation; in contrast, all six subjects in the sham acupuncture at the sham point group responded with nothing other than non-sensation. Compared to the scan results from subjects who experienced non-sensation, SPECT scans from subjects with de qi sensation demonstrated significant activated points mainly located in brodmann areas 6, 8, 19, 21, 28, 33, 35, 37, 47, the parahippocampal gyrus, lentiform nucleus, claustrum and red nucleus; deactivated points were seen in brodmann areas 9 and 25. Verum acupuncture at true acupuncture points is more likely to elicit de qi sensation. De qi sensations mainly resulted in brain area activations, but not deactivations. These brain areas are related to the curative effect of Te5. The acupuncture needle sensations of de qi and sharp pain are associated with different patterns of activations and deactivations in the brain.

  2. Phase 1 RCRA Facility Investigation/Corrective Measures Study Work Plan for Single-Shell Tank (SST) Waste Management Areas

    International Nuclear Information System (INIS)

    MCCARTHY, M.M.

    1999-01-01

    This document is the master work plan for the Resource Conservation and Recovery Act of 1976 (RCRA) Corrective Action Program (RCAP) for single-shell tank (SST) farms at the US. Department of Energy's (DOE'S) Hanford Site. The DOE Office of River Protection (ORP) initiated the RCAP to address the impacts of past and potential future tank waste releases to the environment. This work plan defines RCAP activities for the four SST waste management areas (WMAs) at which releases have contaminated groundwater. Recognizing the potential need for future RCAP activities beyond those specified in this master work plan, DOE has designated the currently planned activities as ''Phase 1.'' If a second phase of activities is needed for the WMAs addressed in Phase 1, or if releases are detected at other SST WMAs, this master work plan will be updated accordingly

  3. Double versus single cartridge of 4% articaine infiltration into the retro-molar area for lower third molar surgery

    Science.gov (United States)

    2017-01-01

    Background There are no studies regarding 4% articaine infiltration injection into the retro-molar area for an impacted lower third molar (LITM) surgery. This study aimed to evaluate the efficacy of infiltration using 1.7 ml (single cartridge: SC) of 4% articaine versus 3.4 ml (double cartridges: DC) of 4% articaine with 1:100,000 epinephrine in LITM surgery. Method This study involved 30 healthy patients with symmetrical LITM. The patients were assigned to receive either a DC or SC of 4% articaine with 1:100,000 epinephrine as a local anesthetic for each operation. Onset, duration, profoundness, need for additional anesthetic administration, total volume of anesthetic used, vitality of the tooth, and pain score during operation were recorded. Results The DC of 4 % articaine had a significantly higher success rate (83.3%) than did the SC (53.3%; P molar region can be an alternative anesthetic for LITM surgery. PMID:28879339

  4. Phase 1 RCRA Facility Investigation & Corrective Measures Study Work Plan for Single Shell Tank (SST) Waste Management Areas

    Energy Technology Data Exchange (ETDEWEB)

    MCCARTHY, M.M.

    1999-08-01

    This document is the master work plan for the Resource Conservation and Recovery Act of 1976 (RCRA) Corrective Action Program (RCAP) for single-shell tank (SST) farms at the US. Department of Energy's (DOE'S) Hanford Site. The DOE Office of River Protection (ORP) initiated the RCAP to address the impacts of past and potential future tank waste releases to the environment. This work plan defines RCAP activities for the four SST waste management areas (WMAs) at which releases have contaminated groundwater. Recognizing the potential need for future RCAP activities beyond those specified in this master work plan, DOE has designated the currently planned activities as ''Phase 1.'' If a second phase of activities is needed for the WMAs addressed in Phase 1, or if releases are detected at other SST WMAs, this master work plan will be updated accordingly.

  5. Radionuclide deflation effects at contaminated environmental area in case of single and steady discharges to the atmosphere

    International Nuclear Information System (INIS)

    Makhon'ko, K.P.

    1984-01-01

    The effects of wind generation of radioactive dust in the area contaminated as a result of single or steady radionuclide discharges to the atmosphere are considered. Calculations are given on changing in time of the deflation coefficient Ksub(α) cm -1 on the base of the radionuclides migration rate account into the depth from a surface dust-forming soil layer and irradiation dose for account of radionuclides penetrated by food chains and into respiratory organs as a result of dusting of the contaminated zone. It is shown that the deflation effects play an essential part in case of emergency discharges owing to the possibility of including radionuclides in food chains through plants. The numerical calculations are performed for 90 Sr and 137 Cs and for light and heavy natural deposit soils

  6. Double versus single cartridge of 4% articaine infiltration into the retro-molar area for lower third molar surgery.

    Science.gov (United States)

    Sawang, Kamonpun; Chaiyasamut, Teeranut; Kiattavornchareon, Sirichai; Pairuchvej, Verasak; Bhattarai, Bishwa Prakash; Wongsirichat, Natthamet

    2017-06-01

    There are no studies regarding 4% articaine infiltration injection into the retro-molar area for an impacted lower third molar (LITM) surgery. This study aimed to evaluate the efficacy of infiltration using 1.7 ml (single cartridge: SC) of 4% articaine versus 3.4 ml (double cartridges: DC) of 4% articaine with 1:100,000 epinephrine in LITM surgery. This study involved 30 healthy patients with symmetrical LITM. The patients were assigned to receive either a DC or SC of 4% articaine with 1:100,000 epinephrine as a local anesthetic for each operation. Onset, duration, profoundness, need for additional anesthetic administration, total volume of anesthetic used, vitality of the tooth, and pain score during operation were recorded. The DC of 4 % articaine had a significantly higher success rate (83.3%) than did the SC (53.3%; P molar region can be an alternative anesthetic for LITM surgery.

  7. Online Characterisation of Mineral Dust Aerosol by Single Particle Mass Spectrometry: Mineralogical Signatures of Potential Source Areas in North Africa.

    Science.gov (United States)

    Marsden, N. A.; Allan, J. D.; Flynn, M.; Ullrich, R.; Moehler, O.; Coe, H.

    2017-12-01

    The mineralogy of individual dust particles is important for atmospheric processes because mineralogy influences optical properties, their potential to act as ice nucleating particles (INP) and geochemical cycling of elements to the ocean. Bulk mineralogy of transported mineral dust has been shown to be a reflection of the source area and size fractionation during transport. Online characterisation of single particle mineralogy is highly desirable as the composition of individual particles can be reported at a temporal resolution that is relevant to atmospheric processes. Single particle mass spectrometry (SPMS) has indentified and characterised the composition of ambient dust particles but is hampered by matrix effects that result in a non-quantatative measurement of composition. The work presented describes a comparison of mass spectral characteristics of sub 2.5μm particle fractions generated from; i) nominally pure samples from the clay mineral society (CMS), ii) soil samples collected from potential source areas in North Africa and iii) ambient measurement of transported African dust made at the Cape Verde Islands. Using a novel approach to analyse the mass spectra, the distinct characteristics of the various dust samples are obtained from the online measurements. Using this technique it was observed that dust generated from sources on the North West Margin of the Sahara Desert have distinct characteristics of illite in contrast to the kaolinitic characteristics of dust generated from sources in the Sahel. These methods offer great potential for describing the hourly variation in the source and mineralogy of transported mineral dust and the online differentiation of mineral phase in multi-mineralic dust samples.

  8. From soil to leaves--aluminum fractionation by single step extraction procedures in polluted and protected areas.

    Science.gov (United States)

    Frankowski, Marcin; Zioła-Frankowska, Anetta; Siepak, Jerzy

    2013-09-30

    The paper presents the fractionation of aluminum in the samples of soil and plants of different species using a selective single-step extraction method. The study was conducted in the area located near a chemical plant, which for many years served as a post-crystallization leachate disposal site storing chemical waste (sector I), and in the area around the site: in Wielkopolski National Park, Rogalin Landscape Park and toward the infiltration ponds at the "Dębina" groundwater well-field for the city of Poznań (Poland) (sector II). The results of aluminum fractionation in samples of soil, leaves and plants showed heavy pollution with aluminum, especially in the water soluble aluminum fraction - Alsw (maximum concentration of aluminum in soil extract was 234.8 ± 4.8 mg kg(-1), in the leaves of Betula pendula it was 107.4 ± 1.8 mg kg(-1) and in the plants of Artemisia vulgaris (root) and Medicago sativa (leaves) it amounted to 464.7 ± 10.7 mg kg(-1)and 146.8 ± 1.2 mg kg(-1) respectively). In addition, the paper presents the problem of organic aluminum fractionation in biological samples and it shows the relationship between aluminum concentration in soil and the analysed woody and herbaceous species. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. The effect of bi-directional reflectance distribution function on the estimation of vegetation indices and leaf area index (LAI): A case study of the vegetation in succession stages after forest fire in northwestern Canada

    International Nuclear Information System (INIS)

    Hasegawa, K.; Matsuyama, H.; Tsuzuki, H.; Sweda, T.

    2006-01-01

    The effect of the dependence of the satellite data on sun/sensor geometry must be considered in the case of monitoring vegetation from satellites. Vegetation structure causes uneven scattering of sunlight, which is expressed by bi-directional reflectance distribution function (BRDF). The purpose of this study is to estimate the effect of BRDF of monitoring vegetation using the reflectance of visible and near-infrared bands. We investigated the vegetation in succession stages after forest fire (main species: spruce) in the northwestern Canada. BRF (Bidirectional Reflectance Factor) was measured in the seven sites of some succession stages, along with the measurements of leaf area index (LAI) and biomass. The main results obtained in this study are summarized as follows. (1) In each site, the difference of Normalized Difference Vegetation Index (NDVI) value around 0.1-0.2 was caused by BRDF when the sensor angle was changed from -15deg to 15 deg, being equivalent to the standard image of IKONOS. Also, LAI estimated by NDVI varied from 22% to 65% of the average. (2) The robustness of other vegetation indices to BRDF was compared. The reflectance of the near-infrared band normalized by the sum of other bands (nNIR), and Global Environmental Monitoring Index (GEMI) were investigated along with NDVI. It is clarified that nNIR was most robust in the site where vegetation existed. GEMI was most robust in the sites of scarce vegetation, while NDVI was strongly affected by BRDF in such sites

  10. Heat losses in the single family houses area of Praestmarken, Vaexjoe, Sweden; Vaermefoerluster i smaahusomraadet Praestmarken, Vaexjoe

    Energy Technology Data Exchange (ETDEWEB)

    Zinko, Heimo [ZW Energiteknik, Nykoeping (Sweden); Boehm, Benny [Technical Univ. of Danmark, Lyngby (Denmark)

    2005-07-01

    The Swedish district heating nets are in many places at the border of their extension possibilities, i. e. it is difficult to find new customers within areas with adequate heat density. On the other hand, Sweden's energy situation in future would improve if cogeneration based heat and power production could be increased, both as far delivered power and delivered kWh are concerned. That means that new district heating customers are very desirable and that is why detached houses have gained increased interest for connection to district heating. Before the continued extension of district heating to areas with detached houses, it is therefore of interest to study the function of district heating in areas with low line density. One of the important questions is of course heat loss from mains and service pipes, but also other questions such as operational conditions in summer time are to be studied. Swedish District Heating Association has therefore in cooperation with Vaexjoe Energi AB (VEAB) and a research group from the Technical University of Denmark (DTU) and ZW Energiteknik AB carried out a project for studying in detail the heat losses from a local district heating net for detached houses called Praestmarken. The selected net delivers heat to an area with 103 detached houses connected to the district heating net of VEAB. The houses are relatively new, built in the time between 1995 and 2004 and the DH-net was also built during the same period. The average annual heat load is about 15,000 kWh/house and the trench length is about 3,000 m, resulting in a line density of about 0.5 MWh/m. The network consists of 78 % twin pipes and 22 % single preinsulated pipes. The measurement method is based on determining the energy difference between the heat delivered to the area and the sum of all energy delivered to the substations of the houses. The total energy delivered to the area was measured by means of a main meter connected to the distant metering system of VEAB

  11. A comparative analysis of stomata and leaf trichome characteristics in Quercus robur L. genotypes

    Directory of Open Access Journals (Sweden)

    Nikolić Nataša P.

    2003-01-01

    Full Text Available The objective of this study was to determine genotype variability of leaf trichome and stoma characteristics. Leaves were sampled from seventeen pedunculate oak (Quercus robur L genotypes originating from clonal seed orchard Banov Brod (Srem, the Vojvodina Province. The pedunculate oak has hypostomatal leaves. Statistically significant differences were found for the dimensions and density of stomata. Genotype variability of stomatal dimensions was less pronounced in comparison with their density (CV = 8.88%. Stomata number ranged from 530 to 791 per mm2 of leaf area; genotypes 18 and 25 could be distinguished from the others for the highest stomata number per leaf unit area, genotype 35 for the lowest number. In all genotypes, only solitary eglandular trichomes were observed on the adaxial leaf surface while both solitary eglandular and uniseriate glandular hairs were present on the abaxial surface. Single glandular trichomes were observed in all genotypes, while some of them were characterized by the presence of two (genotypes 4, 5, 6, 16, 22, 25, 28, 29, 30, 35, 38, 40, and 85 or three (genotypes 16, 25, 35 hairs joined by their basal cells.

  12. Economical Evaluation of Single Irrigation Efficient of Rainfed Barley under Different Agronimic Managements at On-farm Areas

    Directory of Open Access Journals (Sweden)

    Ali Reza Tavakoli

    2016-02-01

    Full Text Available Introduction: Two of the main challenges in developing countries are food production and trying to get a high income for good nutrition and reduction of poverty. Cereals and legumes are the most important crops in the rainfed areas of the country occupying the majority of dry land areas. Irrigated production systems had a main role in food production in the past years; but unfortunately, in recent years, with high population and competition of industry and environment with agricultural sectors, getting adequate irrigation water is difficult. The main purpose of this study is to determine the best option of crop agronomic management. Rainfed agriculture is important in the world; because this production system establishes %80 of the agriculture area and prepares %70 of the food in the world. In the Lorestan province, production area for rainfed barley is 120,000 ha and the amount produced is 120000 ton (approximately 1009 kg per ha. The purposes of this study were to evaluate cost, benefit and profit of rainfed barley production, economical and non-economical substitution of treatments in different agronomic management, study of sale return, cost ratio, determining break-even of price and comparing it with the guaranteed price of barley and estimating the value of water irrigation. Materials and Methods: This research was carried out by sample farmers (12 farmers on rainfed barley at the Honam selected site in the Lorestan province during 2005-07. At on-farm areas of the upper Karkheh River Basin (KRB three irrigation levels were analyzed (rainfed, single irrigation at planting time and single irrigation at spring time under two agronomic managements (advanced management (AM and traditional management (TM. Data was analyzed by Partial Budgeting (PB technique, Marginal Benefit-Cost Ratio (MBCR, and economical and non-economical test. For estimation of net benefit the following formula was used: (1 Where: N.B: Net income (Rials/ ha , B(w : Gross

  13. Assessing the Transferability of Statistical Predictive Models for Leaf Area Index Between Two Airborne Discrete Return LiDAR Sensor Designs Within Multiple Intensely Managed Loblolly Pine Forest Locations in the South-Eastern USA

    Science.gov (United States)

    Sumnall, Matthew; Peduzzi, Alicia; Fox, Thomas R.; Wynne, Randolph H.; Thomas, Valerie A.; Cook, Bruce

    2016-01-01

    Leaf area is an important forest structural variable which serves as the primary means of mass and energy exchange within vegetated ecosystems. The objective of the current study was to determine if leaf area index (LAI) could be estimated accurately and consistently in five intensively managed pine plantation forests using two multiple-return airborne LiDAR datasets. Field measurements of LAI were made using the LiCOR LAI2000 and LAI2200 instruments within 116 plots were established of varying size and within a variety of stand conditions (i.e. stand age, nutrient regime and stem density) in North Carolina and Virginia in 2008 and 2013. A number of common LiDAR return height and intensity distribution metrics were calculated (e.g. average return height), in addition to ten indices, with two additional variants, utilized in the surrounding literature which have been used to estimate LAI and fractional cover, were calculated from return heights and intensity, for each plot extent. Each of the indices was assessed for correlation with each other, and was used as independent variables in linear regression analysis with field LAI as the dependent variable. All LiDAR derived metrics were also entered into a forward stepwise linear regression. The results from each of the indices varied from an R2 of 0.33 (S.E. 0.87) to 0.89 (S.E. 0.36). Those indices calculated using ratios of all returns produced the strongest correlations, such as the Above and Below Ratio Index (ABRI) and Laser Penetration Index 1 (LPI1). The regression model produced from a combination of three metrics did not improve correlations greatly (R2 0.90; S.E. 0.35). The results indicate that LAI can be predicted over a range of intensively managed pine plantation forest environments accurately when using different LiDAR sensor designs. Those indices which incorporated counts of specific return numbers (e.g. first returns) or return intensity correlated poorly with field measurements. There were

  14. SMEX04 Leaf Area Index Data: Arizona

    Data.gov (United States)

    National Aeronautics and Space Administration — Notice to Data Users: The documentation for this data set was provided solely by the Principal Investigator(s) and was not further developed, thoroughly reviewed, or...

  15. Nondestructive estimation of leaf area for pondberry

    Science.gov (United States)

    Brian Roy Lockhart; Emile S. Gardiner; Theran P. Stautz; Theodore D. Leininger; Paul B. Hamel; Kristina F. Connor; Nathan M. Schiff; A. Dan. Wilson; Margaret S. Devall

    2007-01-01

    Pondberry (Lindera melissifolia [Walt.] Blume) is a federally listed endangered shrub found as isolated populations in seasonally flooded forests across the Southeastern United States. Because this shrub is rare, it has received little research attention, and basic knowledge of its ecology and physiology is lacking. To facilitate future ecological...

  16. Automated Leaf Tracking using Multi-view Image Sequences of Maize Plants for Leaf-growth Monitoring

    Science.gov (United States)

    Das Choudhury, S.; Awada, T.; Samal, A.; Stoerger, V.; Bashyam, S.

    2017-12-01

    Extraction of phenotypes with botanical importance by analyzing plant image sequences has the desirable advantages of non-destructive temporal phenotypic measurements of a large number of plants with little or no manual intervention in a relatively short period of time. The health of a plant is best interpreted by the emergence timing and temporal growth of individual leaves. For automated leaf growth monitoring, it is essential to track each leaf throughout the life cycle of the plant. Plants are constantly changing organisms with increasing complexity in architecture due to variations in self-occlusions and phyllotaxy, i.e., arrangements of leaves around the stem. The leaf cross-overs pose challenges to accurately track each leaf using single view image sequence. Thus, we introduce a novel automated leaf tracking algorithm using a graph theoretic approach by multi-view image sequence analysis based on the determination of leaf-tips and leaf-junctions in the 3D space. The basis of the leaf tracking algorithm is: the leaves emerge using bottom-up approach in the case of a maize plant, and the direction of leaf emergence strictly alternates in terms of direction. The algorithm involves labeling of the individual parts of a plant, i.e., leaves and stem, following graphical representation of the plant skeleton, i.e., one-pixel wide connected line obtained from the binary image. The length of the leaf is measured by the number of pixels in the leaf skeleton. To evaluate the performance of the algorithm, a benchmark dataset is indispensable. Thus, we publicly release University of Nebraska-Lincoln Component Plant Phenotyping dataset-2 (UNL-CPPD-2) consisting of images of the 20 maize plants captured by visible light camera of the Lemnatec Scanalyzer 3D high throughout plant phenotyping facility once daily for 60 days from 10 different views. The dataset is aimed to facilitate the development and evaluation of leaf tracking algorithms and their uniform comparisons.

  17. Susceptibility of field populations of the fall armyworm (Lepidoptera: Noctuidae) from Florida and Puerto Rico to purified Cry1F protein and corn leaf tissue containing single and pyramided Bt genes

    Science.gov (United States)

    Larval survival of Cry1F-susceptible (FL), -resistant (PR and Cry1F-RR), and -heterozygous (FL x PR and Cry1F-RS) populations of the fall armyworm, Spodoptera frugiperda (J.E. Smith) to purified Cry1F protein and corn leaf tissue of seven Bacillus thuringiensis (Bt) corn hybrids and five non-Bt corn...

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

    Science.gov (United States)

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

    2004-01-01

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

  19. Estimation of thigh muscle cross-sectional area by single- and multifrequency segmental bioelectrical impedance analysis in the elderly.

    Science.gov (United States)

    Yamada, Yosuke; Ikenaga, Masahiro; Takeda, Noriko; Morimura, Kazuhiro; Miyoshi, Nobuyuki; Kiyonaga, Akira; Kimura, Misaka; Higaki, Yasuki; Tanaka, Hiroaki

    2014-01-15

    Bioelectrical impedance analysis (BIA) has been used to estimate skeletal muscle mass, but its application in the elderly is not optimal. The accuracy of BIA may be influenced by the expansion of extracellular water (ECW) relative to muscle mass with aging. Multifrequency BIA (MFBIA) can evaluate the distribution between ECW and intracellular water (ICW), and thus may be superior to single-frequency BIA (SFBIA) to estimate muscle mass in the elderly. A total of 58 elderly participants aged 65-85 years were recruited. Muscle cross-sectional area (CSA) was obtained from computed tomography scans at the mid-thigh. Segmental SFBIA and MFBIA were measured for the upper legs. An index of the ratio of ECW and ICW was calculated using MFBIA. The correlation between muscle CSA and SFBIA was moderate (r = 0.68), but strong between muscle CSA and MFBIA (r = 0.85). ECW/ICW index was significantly and positively correlated with age (P < 0.001). SFBIA tends to significantly overestimate muscle CSA in subjects who had relative expansion of ECW in the thigh segment (P < 0.001). This trend was not observed for MFBIA (P = 0.42). Relative expansion of ECW was observed in older participants. The relative expansion of ECW affects the validity of traditional SFBIA, which is lowered when estimating muscle CSA in the elderly. By contrast, MFBIA was not affected by water distribution in thigh segments, thus rendering the validity of MFBIA for estimating thigh muscle CSA higher than SFBIA in the elderly.

  20. The leaf size-twig size spectrum in evergreen broadleaved forest of ...

    African Journals Online (AJOL)

    Compared to deciduous broad-leaved species, the evergreen broad-leaved species were smaller in total leaf area for a given cross-sectional area or stem mass. This suggests that the species would support less leaf area at a given twig cross-sectional area with increasing environmental stress. And the life form can modify ...

  1. Feeding selectivity by mantled howler monkeys (Alouatta palliata) in relation to leaf secondary chemistry in Hymenaea courbaril.

    Science.gov (United States)

    Welker, B J; König, W; Pietsch, M; Adams, R P

    2007-06-01

    This study is a quantitative examination of primate feeding selectivity in relation to secondary chemistry within a single plant species, Hymenaea courbaril. It provides the first evidence that sesquiterpenes may act as feeding deterrents in mantled howler monkeys. A free-ranging group of mantled howler monkeys at the study site of Sector Santa Rosa, Area de Conservacion Guanacaste, Costa Rica were observed for the 2-month period of H. courbaril leaf flush in 1999. Tree characteristic data and leaf specimens were collected from 22 focal trees. Gas chromatography and mass spectrometry were used to estimate relative percentages of sesquiterpenes in leaf specimens. The monkeys fed only on the youngest leaves and only from particular trees. Whereas leaf stage selectivity was likely governed by tannin content and structural carbohydrates in younger and older leaf stages, respectively, differential tree use may be related to variability in sesquiterpene content. There is evidence that alpha-copaene may have played a role in interindividual tree use, and that cyperene may also be implicated. However, there is no reported evidence of antiherbivore activity for cyperene.

  2. Simulation of Canopy Leaf Inclination Angle in Rice

    Directory of Open Access Journals (Sweden)

    Xiao-cui ZHANG

    2013-11-01

    Full Text Available 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.

  3. Leaf gas exchange of Pachyrhizus ahipa and P. erosus under water and temperature stress

    OpenAIRE

    Leidi, Eduardo O.

    2002-01-01

    Gas exchange, water relations, and leaf traits were studied in the tuberous-root producing legumes ahipa (Pachyrhizus ahipa) and yambean (P. erosus) under different environmental conditions. Differences in leaf traits (hairiness, leaf area, areal leaf mass, stomatal density) and paraheliotropism were found between ahipa and yambean. Under sufficient water supply, the increase in air temperature and decrease in air humidity increased stomatal conductance (gs) and net photosynthetic rate (PN) i...

  4. Leaf spring, and electromagnetic actuator provided with a leaf spring

    NARCIS (Netherlands)

    Berkhoff, Arthur P.; Lemmen, Remco Louis Christiaan

    2002-01-01

    The invention relates to a leaf spring for an electromagnetic actuator and to such an electromagnetic actuator. The leaf spring is formed as a whole from a disc of plate-shaped, resilient material. The leaf spring comprises a central fastening part, an outer fastening part extending therearound and

  5. Determinación del Área Foliar en Fotografías Tomadas con una Cámara Web, un Teléfono Celular o una Cámara Semiprofesional Leaf Area Measurement in Photographs Taken with a Webcam, a Cell Phone or a Semi Professional Camera

    Directory of Open Access Journals (Sweden)

    Natalia Rincón Guerrero

    2012-06-01

    Full Text Available Resumen. Las determinaciones de área foliar son muy usadas en investigación agrícola. Para su cuantificación existen equipos automáticos, pero costosos y de escasa disponibilidad. Para superar estos limitantes, en esta investigación se acoplaron el uso de cámaras digitales (de un teléfono celular, una cámara web o una cámara digital semiprofesional y un software libre para análisis de imágenes (ImageJ, con el fin de determinar el área foliar en forma simple, precisa y a bajo costo. Para estimar la sensibilidad de este sistema, en la primera prueba se compararon las áreas generadas por un medidor de área foliar y por las fotografías tomadas con tres tipos de cámara digital, sobre cuadrados de papel verde de áreas conocidas. En la segunda prueba se correlacionaron los valores de área foliar obtenidos con el medidor de área foliar y los obtenidos a partir del análisis de fotografías de hojas tomadas con las tres cámaras digitales, en cinco especies vegetales, que variaban en morfología y color de hojas. Los resultados indicaron coeficientes de correlación mayores a 0,99 entre los valores de área real de las piezas de papel y los valores de área estimados por el medidor de área foliar o de las fotografías. En la segunda prueba, las mediciones de area foliar obtenidas con el medidor de area foliar y con las cámaras digitales presentaron coeficientes de correlación muy altos (r=1. Los coeficientes de líneas de regresión entre las áreas del medidor de área foliar y de las fotografías del teléfono celular estuvieron entre 0,98 y 1,02, indicando una desviación máxima de 2% comparado con las mediciones del medidor de área foliar. Estos resultados sugieren una gama amplia de posibilidades para este sistema como herramienta para la investigación agrícola y biológica, debido a la disponibilidad de estos equipos que son de bajo costo, fáciles de usar y portátiles.Abstract. Leaf area is a plant trait widely assessed

  6. Taxonomic, phylogenetic, and environmental trade-offs between leaf productivity and persistence.

    Science.gov (United States)

    He, Jin-Sheng; Wang, Xiangping; Flynn, Dan F B; Wang, Liang; Schmid, Bernhard; Fang, Jingyun

    2009-10-01

    Assessing the influence of climate, soil fertility, and species identity on leaf trait relationships is crucial for understanding the adaptations of plants to their environment and for interpreting leaf trait relationships across spatial scales. In a comparative field study of 171 plant species in 174 grassland sites across China, we examined the trade-offs, defined as negative covariance between two traits, between leaf persistence (leaf mass per area, LMA) and leaf productivity (mass-based photosynthetic rate, Amass, N and P content, and photosynthetic N use efficiency, PNUE). We asked to which extent these trade-offs were influenced by: (1) variation among sites within species, decomposed into variation due to climatic and soil variables; (2) variation among species within sites, decomposed into variation among taxonomic, functional, or phylogenetic groups; and (3) the joint contribution of variation among species and sites. We used mixed-model analysis of covariance to partition bivariate relationships between leaf traits into trade-off components. We found significant mass-based persistence-productivity trade-offs of LMA-Amass, LMA-N, LMA-P, and LMA-PNUE consistent with previous broadscale findings. Overall, (1) variation among sites within species explained 14-23%, (2) variation among species within sites explained 20-34%, and (3) the two together explained 42-63% of the total covariance between leaf traits. Interspecific trade-offs of LMA-Amass, LMA-N, and LMA-P were stronger than inter-site ones. A relatively low amount of covariance was explained by climatic and soil variables. However, we found the trade-offs were stronger for LMA-N and LMA-P at higher precipitation and for LMA-PNUE at greater soil fertility, if displayed by major axis regression, which combined both intra- and interspecific variation. Residual trade-offs within species and sites were weak, suggesting that intraspecific, intra-site variation in physiology was less important than variation

  7. Tradeoff between stem hydraulic efficiency and mechanical strength affects leaf-stem allometry in 28 Ficus tree species

    NARCIS (Netherlands)

    Fan, Ze Xin; Sterck, Frank; Zhang, Shi Bao; Fu, Pei Li; Hao, Guang You

    2017-01-01

    Leaf-stem allometry is an important spectrum that linked to biomass allocation and life history strategy in plants, although the determinants and evolutionary significance of leaf-stem allometry remain poorly understood. Leaf and stem architectures - including stem area/mass, petiole area/mass,

  8. 'Dangshansuli' pear leaf

    African Journals Online (AJOL)

    ajl yemi

    2011-12-19

    Dec 19, 2011 ... Effects of calcium, potassium and magnesium on oxalic, malic and citric acid content of Valencia orange leaf tissue. Plant Physiol. 36: 39-101. Ruffner HP, Possner D, Brem S, Rast DM (1984). The physiological role of malic enzyme in grape ripening. Plant, 160: 444-448. Sadka A, Artzi B, Cohen L, Dahan E ...

  9. Single-frequency operation of a broad-area laser diode by injection locking of a complex spatial mode via a double phase conjugate mirror

    NARCIS (Netherlands)

    van Voorst, P.D.; Offerhaus, Herman L.; Boller, Klaus J.

    2006-01-01

    We demonstrate what is believed to be the first phase-coherent locking of a high-power broad-area diode to a single-frequency master laser. We use photorefractive double phase conjugation to lock the diode in a selfoptimized complex spatial mode while the photorefractive crystal diffracts that

  10. Individual mediodorsal thalamic neurons project to multiple areas of the rat prefrontal cortex: A single neuron-tracing study using virus vectors.

    Science.gov (United States)

    Kuramoto, Eriko; Pan, Shixiu; Furuta, Takahiro; Tanaka, Yasuhiro R; Iwai, Haruki; Yamanaka, Atsushi; Ohno, Sachi; Kaneko, Takeshi; Goto, Tetsuya; Hioki, Hiroyuki

    2017-01-01

    The prefrontal cortex has an important role in a variety of cognitive and executive processes, and is generally defined by its reciprocal connections with the mediodorsal thalamic nucleus (MD). The rat MD is mainly subdivided into three segments, the medial (MDm), central (MDc), and lateral (MDl) divisions, on the basis of the cytoarchitecture and chemoarchitecture. The MD segments are known to topographically project to multiple prefrontal areas at the population level: the MDm mainly to the prelimbic, infralimbic, and agranular insular areas; the MDc to the orbital and agranular insular areas; and the MDl to the prelimbic and anterior cingulate areas. However, it is unknown whether individual MD neurons project to single or multiple prefrontal cortical areas. In the present study, we visualized individual MD neurons with Sindbis virus vectors, and reconstructed whole structures of MD neurons. While the main cortical projection targets of MDm, MDc, and MDl neurons were generally consistent with those of previous results, it was found that individual MD neurons sent their axon fibers to multiple prefrontal areas, and displayed various projection patterns in the target areas. Furthermore, the axons of single MD neurons were not homogeneously spread, but were rather distributed to form patchy axon arbors approximately 1 mm in diameter. The multiple-area projections and patchy axon arbors of single MD neurons might be able to coactivate cortical neuron groups in distant prefrontal areas simultaneously. Furthermore, considerable heterogeneity of the projection patterns is likely, to recruit the different sets of cortical neurons, and thus contributes to a variety of prefrontal functions. J. Comp. Neurol. 525:166-185, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  11. A photosynthesis-based two-leaf canopy stomatal ...

    Science.gov (United States)

    A coupled photosynthesis-stomatal conductance model with single-layer sunlit and shaded leaf canopy scaling is implemented and evaluated in a diagnostic box model with the Pleim-Xiu land surface model (PX LSM) and ozone deposition model components taken directly from the meteorology and air quality modeling system—WRF/CMAQ (Weather Research and Forecast model and Community Multiscale Air Quality model). The photosynthesis-based model for PX LSM (PX PSN) is evaluated at a FLUXNET site for implementation against different parameterizations and the current PX LSM approach with a simple Jarvis function (PX Jarvis). Latent heat flux (LH) from PX PSN is further evaluated at five FLUXNET sites with different vegetation types and landscape characteristics. Simulated ozone deposition and flux from PX PSN are evaluated at one of the sites with ozone flux measurements. Overall, the PX PSN simulates LH as well as the PX Jarvis approach. The PX PSN, however, shows distinct advantages over the PX Jarvis approach for grassland that likely result from its treatment of C3 and C4 plants for CO2 assimilation. Simulations using Moderate Resolution Imaging Spectroradiometer (MODIS) leaf area index (LAI) rather than LAI measured at each site assess how the model would perform with grid averaged data used in WRF/CMAQ. MODIS LAI estimates degrade model performance at all sites but one site having exceptionally old and tall trees. Ozone deposition velocity and ozone flux along with LH

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

    Directory of Open Access Journals (Sweden)

    Tawanda W. Gara

    2018-02-01

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

  13. Predicting tropical plant physiology from leaf and canopy spectroscopy.

    Science.gov (United States)

    Doughty, Christopher E; Asner, Gregory P; Martin, Roberta E

    2011-02-01

    A broad regional understanding of tropical forest leaf photosynthesis has long been a goal for tropical forest ecologists, but it has remained elusive due to difficult canopy access and high species diversity. Here we develop an empirical model to predict sunlit, light-saturated, tropical leaf photosynthesis using leaf and simulated canopy spectra. To develop this model, we used partial least squares (PLS) analysis on three tropical forest datasets (159 species), two in Hawaii and one at the biosphere 2 laboratory (B2L). For each species, we measured light-saturated photosynthesis (A), light and CO(2) saturated photosynthesis (A(max)), respiration (R), leaf transmittance and reflectance spectra (400-2,500 nm), leaf nitrogen, chlorophyll a and b, carotenoids, and leaf mass per area (LMA). The model best predicted A [r(2) = 0.74, root mean square error (RMSE) = 2.9 μmol m(-2) s(-1))] followed by R (r(2) = 0.48), and A(max) (r(2) = 0.47). We combined leaf reflectance and transmittance with a canopy radiative transfer model to simulate top-of-canopy reflectance and found that canopy spectra are a better predictor of A (RMSE = 2.5 ± 0.07 μmol m(-2) s(-1)) than are leaf spectra. The results indicate the potential for this technique to be used with high-fidelity imaging spectrometers to remotely sense tropical forest canopy photosynthesis.

  14. Arabidopsis onset of leaf death mutants identify a regulatory pathway controlling leaf senescence

    NARCIS (Netherlands)

    Jing, Hai-Chun; Sturre, Marcel J.G.; Hille, Jacques; Dijkwel, Paul P.

    2002-01-01

    The onset of leaf senescence is controlled by leaf age and ethylene can promote leaf senescence within a specific age window. We exploited the interaction between leaf age and ethylene and isolated mutants with altered leaf senescence that are named as onset of leaf death (old) mutants. Early leaf

  15. Are there any differences in medical emergency team interventions between rural and urban areas? A single-centre cohort study.

    Science.gov (United States)

    Aftyka, Anna; Rybojad, Beata; Rudnicka-Drozak, Ewa

    2014-10-01

    To compare interventions of medical emergency teams in urban and rural areas with particular emphasis on response time and on-site medical rescue activities. A retrospective analysis of ambulance call reports from two emergency medical service substations: one in the city and the other in a rural area. Two emergency medical service substations: one in the city and the other in a rural area. Medical emergency teams. Interventions in the city were associated with a substantially shorter response time in comparison to rural areas. In the city, the distances were generally less than 10 km. In the rural area, however, such short distances accounted for only 7.2% of events, while 33.8% were over 30 km. Medical emergency teams more often acted exclusively on-site or ceased any interventions in rural areas. Compared with the city, actions in the rural setting were associated with significantly increased use of cervical collars and decreased use of intravenous access. The presence of a physician in the team raised the probability of pharmacotherapy. The relationship between medical emergency teams activities and the location of intervention shows the real diversity of the functioning of emergency medical service within a city and rural areas. Further research should aim to improve the generalisability of these findings. © 2014 National Rural Health Alliance Inc.

  16. Evolution of the leaf economics spectrum in herbs: Evidence from environmental divergences in leaf physiology across Helianthus (Asteraceae).

    Science.gov (United States)

    Mason, Chase M; Donovan, Lisa A

    2015-10-01

    The leaf economics spectrum (LES) describes a major axis of plant functional trait variation worldwide, defining suites of leaf traits aligned with resource-acquisitive to resource-conservative ecological strategies. The LES has been interpreted to arise from leaf-level trade-offs among ecophysiological traits common to all plants. However, it has been suggested that the defining leaf-level trade-offs of the LES may not hold within specific functional groups (e.g., herbs) nor within many groups of closely related species, which challenges the usefulness of the LES paradigm across evolutionary scales. Here, we examine the evolution of the LES across 28 species of the diverse herbaceous genus Helianthus (the sunflowers), which occupies a wide range of habitats and climate variation across North America. Using a phylogenetic comparative approach, we find repeated evolution of more resource-acquisitive LES strategies in cooler, drier, and more fertile environments. We also find macroevolutionary correlations among LES traits that recapitulate aspects of the global LES, but with one major difference: leaf mass per area is uncorrelated with leaf lifespan. This indicates that whole-plant processes likely drive variation in leaf lifespan across Helianthus, rather than leaf-level trade-offs. These results suggest that LES patterns do not reflect universal physiological trade-offs at small evolutionary scales. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  17. Leaf absorbance and photosynthesis

    Science.gov (United States)

    Schurer, Kees

    1994-01-01

    The absorption spectrum of a leaf is often thought to contain some clues to the photosynthetic action spectrum of chlorophyll. Of course, absorption of photons is needed for photosynthesis, but the reverse, photosynthesis when there is absorption, is not necessarily true. As a check on the existence of absorption limits we measured spectra for a few different leaves. Two techniques for measuring absorption have been used, viz. the separate determination of the diffuse reflectance and the diffuse transmittance with the leaf at a port of an integrating sphere and the direct determination of the non-absorbed fraction with the leaf in the sphere. In a cross-check both methods yielded the same results for the absorption spectrum. The spectrum of a Fuchsia leaf, covering the short-wave region from 350 to 2500 nm, shows a high absorption in UV, blue and red, the well known dip in the green and a steep fall-off at 700 nm. Absorption drops to virtually zero in the near infrared, with subsequent absorptions, corresponding to the water absorption bands. In more detailed spectra, taken at 5 nm intervals with a 5 nm bandwidth, differences in chlorophyll content show in the different depths of the dip around 550 nm and in a small shift of the absorption edge at 700 nm. Spectra for Geranium (Pelargonium zonale) and Hibiscus (with a higher chlorophyll content) show that the upper limit for photosynthesis can not be much above 700 nm. No evidence, however, is to be seen of a lower limit for photosynthesis and, in fact, some experiments down to 300 nm still did not show a decrease of the absorption although it is well recognized that no photosynthesis results with 300 nm wavelengths.

  18. Comparing Multipollutant Emissions-Based Mobile Source Indicators to Other Single Pollutant and Multipollutant Indicators in Different Urban Areas

    Directory of Open Access Journals (Sweden)

    Michelle M. Oakes

    2014-11-01

    Full Text Available A variety of single pollutant and multipollutant metrics can be used to represent exposure to traffic pollutant mixtures and evaluate their health effects. Integrated mobile source indicators (IMSIs that combine air quality concentration and emissions data have recently been developed and evaluated using data from Atlanta, Georgia. IMSIs were found to track trends in traffic-related pollutants and have similar or stronger associations with health outcomes. In the current work, we apply IMSIs for gasoline, diesel and total (gasoline + diesel vehicles to two other cities (Denver, Colorado and Houston, Texas with different emissions profiles as well as to a different dataset from Atlanta. We compare spatial and temporal variability of IMSIs to single-pollutant indicators (carbon monoxide (CO, nitrogen oxides (NOx and elemental carbon (EC and multipollutant source apportionment factors produced by Positive Matrix Factorization (PMF. Across cities, PMF-derived and IMSI gasoline metrics were most strongly correlated with CO (r = 0.31–0.98, while multipollutant diesel metrics were most strongly correlated with EC (r = 0.80–0.98. NOx correlations with PMF factors varied across cities (r = 0.29–0.67, while correlations with IMSIs were relatively consistent (r = 0.61–0.94. In general, single-pollutant metrics were more correlated with IMSIs (r = 0.58–0.98 than with PMF-derived factors (r = 0.07–0.99. A spatial analysis indicated that IMSIs were more strongly correlated (r > 0.7 between two sites in each city than single pollutant and PMF factors. These findings provide confidence that IMSIs provide a transferable, simple approach to estimate mobile source air pollution in cities with differing topography and source profiles using readily available data.

  19. Classes de perfilhos na composição do índice de área foliar em pastos de capim-elefante Tiller classes on leaf area index composition in elephant grass swards

    Directory of Open Access Journals (Sweden)

    Carlos Augusto Brandão de Carvalho

    2007-04-01

    Full Text Available O trabalho foi conduzido de outubro de 2002 a abril de 2003, em Coronel Pacheco, MG, com o objetivo de avaliar os efeitos da altura do resíduo pós-pastejo (50 e 100 cm sobre a radiação fotossinteticamente ativa (RFA interceptada pelo dossel e o coeficiente de extinção luminosa; a contribuição relativa de classes de perfilhos (basais e aéreos sobre o índice de área foliar (IAF e o acúmulo de forragem (AF, em pastos de capim-elefante (Pennisetum purpureum Schum. cv. Napier manejados com intervalos de 30 dias entre pastejos. Foi usado o delineamento blocos completos ao acaso e um arranjo de parcelas subdivididas com quatro repetições, com alturas de resíduo alocadas nas parcelas e as classes de perfilhos nas subparcelas. O IAF, a interceptação da RFA e o coeficiente de extinção luminosa foram influenciados pela altura do resíduo pós-pastejo. As interceptações da RFA foram maiores no verão do que na primavera, em pastos manejados com resíduo de 100 cm. As variações do IAF e da interceptação da RFA não estiveram associados, durante todos os ciclos de pastejo. O IAF e o AF apresentaram variações sazonais, relacionadas à participação de perfilhos basais e aéreos, na população de perfilhos do pasto.The work was carried out at Coronel Pacheco, MG, Brazil, from October 2002 to April 2003 with the objective of evaluating the effects of two post-grazing residues (50 and 100 cm on the interception of photosynthetically active radiation (PAR and light extinction coefficient; relative contribution of tiller classes (basal and aerial to leaf area index (LAI and herbage accumulation of elephant grass swards (Pennisetum purpureum Schum. cv. Napier subjected to grazing intervals of 30 days. The experimental design was a complete randomized block, and treatments were allocated to experimental units using a split plot arrangement, with four replicates. Post-grazing residues were allocated to plots and tiller classes to sub plots

  20. Effect of acid mist and air pollutants on yellow-poplar seedling height and leaf growth

    Science.gov (United States)

    Leon S. Dochinger; Keith F. Jensen; Keith F. Jensen

    1985-01-01

    One-year-old yellow-poplar seedlings were treated with acid mist at pH 2.5, 3.5, 4.5, and 5.5 either alone or in combination with 0.1 ppm 03, S02, and NO2 or NO2 plus S02. After 4 and 8 weeks of treatment, height, leaf area, and leaf and new shoot weight were determined and growth analysis variables calculated. Height, leaf area, and dry weight decreased with...

  1. Borehole Data Package for Calendar Year 2000 - 2001 RCRA Wells at Single-Shell Tank Waste Management Area S-SX

    Energy Technology Data Exchange (ETDEWEB)

    Horton, Duane G.; Johnson, Vernon G.

    2001-08-15

    Six new resource conservation and Recovery Act (RCRA) groundwater monitoring wells were installed at the single-shell tank farm Waste Management Area S-SX in July 2000 through March 2001 in partial fulfillment of Tri-Party Agreement milestones M-24-00L and M-24-00M. This document describes the drilling, construction, sampling and analyses of samples from the wells.

  2. Results of phase 1 groundwater quality assessment for Single-Shell Tank Waste Management Areas B-BX-BY at the Hanford Site

    International Nuclear Information System (INIS)

    Narbutovskih, S.M.

    1998-02-01

    Pacific Northwest National Laboratory conducted a Phase 1 (or first determination) groundwater quality assessment for the US Department of Energy, Richland Operations Office, in accordance with the Federal Facility Compliance Agreement. The purpose of the assessment was to determine if the Single-Shell Tank Waste Management Area (WMA) B-BX-BY has impacted groundwater quality. This report will document the evidence demonstrating that the WMA has impacted groundwater quality

  3. Results of phase 1 groundwater quality assessment for Single-Shell Tank Waste Management Areas B-BX-BY at the Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Narbutovskih, S.M.

    1998-02-01

    Pacific Northwest National Laboratory conducted a Phase 1 (or first determination) groundwater quality assessment for the US Department of Energy, Richland Operations Office, in accordance with the Federal Facility Compliance Agreement. The purpose of the assessment was to determine if the Single-Shell Tank Waste Management Area (WMA) B-BX-BY has impacted groundwater quality. This report will document the evidence demonstrating that the WMA has impacted groundwater quality.

  4. A real-time integrator of storage-area contents for SA 40B or DIDAC 800 analyzers. Use in the digital single-channel mode

    International Nuclear Information System (INIS)

    Rigaudiere, Roger; Daburon, M.-L.

    1976-09-01

    An apparatus was developed in order to sum up, during counting, the channel contents from several storage areas of SA 40 B or DIDAC 800 multichannel analyzers. The pulse number stored in the energy bands interesting the operator are known and if necessary subsequent operation can be modified accordingly. Coupled with an autonomous amplitude encoder, this apparatus can be operated in the digital single-channel mode [fr

  5. Picosecond time-resolved laser pump/X-ray probe experiments using a gated single-photon-counting area detector

    DEFF Research Database (Denmark)

    Ejdrup, T.; Lemke, H.T.; Haldrup, Martin Kristoffer

    2009-01-01

    The recent developments in X-ray detectors have opened new possibilities in the area of time-resolved pump/probe X-ray experiments; this article presents the novel use of a PILATUS detector to achieve X-ray pulse duration limited time-resolution at the Advanced Photon Source (APS), USA. The capab......The recent developments in X-ray detectors have opened new possibilities in the area of time-resolved pump/probe X-ray experiments; this article presents the novel use of a PILATUS detector to achieve X-ray pulse duration limited time-resolution at the Advanced Photon Source (APS), USA...

  6. Leaf thermotolerance in dry tropical forest tree species: relationships with leaf traits and effects of drought.

    Science.gov (United States)

    Sastry, Aniruddh; Guha, Anirban; Barua, Deepak

    2018-02-01

    Understanding how tropical trees will respond to extreme temperatures and drought is essential to predict how future increases in the severity, frequency and duration of extreme climatic events will affect tropical systems. In this study, we investigated leaf thermotolerance by quantifying the temperatures that resulted in a 50 % decrease in photosystem II function (T 50 ) in experimentally grown saplings of 12 tree species from a seasonally dry tropical forest. We examined the relationship of thermotolerance with leaf functional traits and photosynthetic rates. Additionally, we tested how water limitation altered thermotolerance within species, and examined the relationship between thermotolerance and drought tolerance among species. Thermotolerance ranged from 44.5 to 48.1 °C in the least and most thermotolerant species, respectively. The observed variation in thermotolerance indicates that the upper limits of leaf function are critically close to maximum temperatures in this region, and that these species will be vulnerable to, and differentially affected by, future warming. Drought increased temperature tolerance, and species that were more drought tolerant were also more thermotolerant. Importantly, thermotolerance was positively related to the key leaf functional trait-leaf mass per area (LMA), and congruent with this, negatively related to photosynthetic rates. These results indicate that more productive species with lower LMA and higher photosynthetic rates may be more vulnerable to heat and drought stress, and more likely to be negatively affected by future increases in extreme climatic events.

  7. 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

  8. Leaf life span plasticity in tropical seedlings grown under contrasting light regimes.

    Science.gov (United States)

    Vincent, Gregoire

    2006-02-01

    The phenotypic plasticity of leaf life span in response to low resource conditions has a potentially large impact on the plant carbon budget, notably in evergreen species not subject to seasonal leaf shedding, but has rarely been well documented. This study evaluates the plasticity of leaf longevity, in terms of its quantitative importance to the plant carbon balance under limiting light. Seedlings of four tropical tree species with contrasting light requirements (Alstonia scholaris, Hevea brasiliensis, Durio zibethinus and Lansium domesticum) were grown under three light regimes (full sunlight, 45 % sunlight and 12 % sunlight). Their leaf dynamics were monitored over 18 months. All species showed a considerable level of plasticity with regard to leaf life span: over the range of light levels explored, the ratio of the range to the mean value of life span varied from 29 %, for the least plastic species, to 84 %, for the most. The common trend was for leaf life span to increase with decreasing light intensity. The plasticity apparent in leaf life span was similar in magnitude to the plasticity observed in specific leaf area and photosynthetic rate, implying that it has a significant impact on carbon gain efficiency when plants acclimate to different light regimes. In all species, median survival time was negatively correlated with leaf photosynthetic capacity (or its proxy, the nitrogen content per unit area) and leaf emergence rate. Longer leaf life spans under low light are likely to be a consequence of slower ageing as a result of a slower photosynthetic metabolism.

  9. Evidence of the effects of fire on branching and leaf development in cerrado trees

    Directory of Open Access Journals (Sweden)

    João Paulo Souza

    Full Text Available ABSTRACT We discuss evidence of effects of an accidental fire on shoot growth and leaf development in six cerrado tree species with distinct leaf phenologies. Buds of all six species were marked before shoot and leaf emergence in the dry season. After fire, leaf and shoot growth were monitored weekly and specific leaf area (SLA was determined. Shoot order was determined in the growing season. Evergreens and semideciduous woody species had rapid leaf and shoot growth and decreased leaf life span (LLS after fire compared with published data for evergreens in cerrado areas without fire. On the other hand, Kielmeyera variabilis, a deciduous species, showed intense branching and produced two orders of shoots in one growing season. Fires promote rapid leaf and shoot growth in evergreens owing to reserve accumulations that allow survivorship after disturbances. However, the leaves produced by evergreens after fire had high SLAs and were discarded before the next rainy season (short LLS. This leaf cohort was produced with less carbon per leaf, and the decreased LLS prevented herbivory and water loss during the dry season. Fire is an important factor of cerrado environments, influencing leaf production and shoot architecture in cerrado trees.

  10. Allometric models for determining leaf area in the ‘PH-16’ cocoa tree in the shade and in full sun = Modelos alométricos para determinação da área foliar de cacaueiro ‘PH-16’ em sombreamento e pleno sol

    Directory of Open Access Journals (Sweden)

    Edilson Romais Schmildt

    2017-03-01

    Full Text Available The aim of this work was to study the statistical modelling of leaf area in the cocoa tree (Theobroma cacao L. ‘PH - 16’, in a shaded environment and in full sun. Two hundred leaves (100 from plants grown in the shade and 100 grown in full sun were randomly collected from cacao plants in plantations in the city of Linhares in the State of Espírito Santo, Brazil, to study their linear measurements. The leaves were separated into two groups, one to estimate the equations and the other to validate the equations. All leaves were characterised for length (C, width (L and leaf area. Leaf area was estimated by linear, power and exponential models from the measurements of C, L and CL as independent variables. When validating the equations, the equation proposed by Azomaning and Lockard was also evaluated. There is a difference in leaf morphology between cocoa grown in the shade and in full sun, however the environment does not statistically affect the intercept in the linear and power models, justifying modelling from the joint use of leaves of the two environments. It is possible to estimate leaf area in the cocoa plant from allometric equations, with the equations that use the product of CL as the explanatory variable being more precise. The power model equation AFE = 0.6736 (LW1.0036 is best suited for estimating leaf area in ‘PH-16’ cocoa, and can be used both for the leaves of plants in shaded environments and in full sun. = Objetivou-se com este trabalho estudar a modelagem estatística da área foliar de cacaueiro (Theobroma cacao L. ‘PH-16’, em ambiente sombreado e a pleno sol. Coletaram-se aleatoriamente 200 folhas de cacaueiro (100 foram de plantas em cultivo sombreado e 100 em cultivo a pleno sol, situadas em lavouras cacaueiras no município de Linhares (ES, para estudo de suas medidas lineares. As folhas foram separadas em dois grupos, um para estimativa das equações e outro para validação dessas equações. Todas as folhas

  11. 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.

  12. Initial Results of Accelerated Stress Testing on Single-Channel and Multichannel Drivers: Solid-State Lighting Technology Area

    Energy Technology Data Exchange (ETDEWEB)

    None

    2018-02-28

    This report is the first in a series of studies on accelerated stress testing (AST) of drivers used for SSL luminaires, such as downlights, troffers, and streetlights. A representative group of two-stage commercial driver products was exposed to an AST environment consisting of 75°C and 75% relative humidity (7575). These drivers were a mix of single-channel drivers (i.e., a single output current for one LED primary) and multichannel drivers (i.e., separate output currents for multiple LED primaries). This AST environment was chosen because previous testing on downlights with integrated drivers demonstrated that 38% of the sample population failed in less than 2,500 hours of testing using this method. In addition to AST test results, the performance of an SSL downlight product incorporating an integrated, multichannel driver during extended room temperature operational life (RTOL) testing is also reported. A battery of measurements was used to evaluate these products during accelerated testing, including full electrical characterization (i.e., power consumption, PF, total harmonic distortion [THD], and inrush current) and photometric characterization of external LED loads attached to the drivers (i.e., flicker performance and lumen maintenance).

  13. Leaf development: A cellular perspective

    Directory of Open Access Journals (Sweden)

    Gerrit TS Beemster

    2014-07-01

    Full Text Available Through its photosynthetic capacity the leaf provides the basis for growth of the whole plant. In order to improve crops for higher productivity and resistance for future climate scenarios, it is important to obtain a mechanistic understanding of leaf growth and development and the effect of genetic and environmental factors on the process. Cells are both the basic building blocks of the leaf and the regulatory units that integrate genetic and environmental information into the developmental program. Therefore, to fundamentally understand leaf development, one needs to be able to reconstruct the developmental pathway of individual cells (and their progeny from the stem cell niche to their final position in the mature leaf. To build the basis for such understanding, we review current knowledge on the spatial and temporal regulation mechanisms operating on cells, contributing to the formation of a leaf. We focus on the molecular networks that control exit from stem cell fate, leaf initiation, polarity, cytoplasmic growth, cell division, endoreduplication, transition between division and expansion, expansion and differentiation and their regulation by intercellular signaling molecules, including plant hormones, sugars, peptides, proteins and microRNAs. We discuss to what extent the knowledge available in the literature is suitable to be applied in systems biology approaches to model the process of leaf growth, in order to better understand and predict leaf growth starting with the model species Arabidopsis thaliana.

  14. RCRA Assessment Plan for Single-Shell Tank Waste Management Area S-SX at the Hanford Site

    International Nuclear Information System (INIS)

    Chou, C.J.; Johnson, V.G.

    1999-01-01

    A groundwater quality assessment plan was prepared for waste management area S-SX at the Hanford Site. Groundwater monitoring is conducted at this facility in accordance with Title 40, Code of Federal Regulation (CFR) Part 265, Subpart F [and by reference of Washington Administrative Code (WAC) 173-303-400(3)]. The facility was placed in assessment groundwater monitoring program status after elevated waste constituents and indicator parameter measurements (i.e., chromium, technetium-99 and specific conductance) in downgradient monitoring wells were observed and confirmed. A first determination, as allowed under 40 CFR 265.93(d), provides the owner/operator of a facility an opportunity to demonstrate that the regulated unit is not the source of groundwater contamination. Based on results of the first determination it was concluded that multiple source locations in the waste management area could account for observed spatial and temporal groundwater contamination patterns. Consequently, a continued investigation is required. This plan, developed using the data quality objectives process, is intended to comply with the continued investigation requirement. Accordingly, the primary purpose of the present plan is to determine the rate and extent of dangerous waste (hexavalent chromium and nitrate) and radioactive constituents (e.g., technetium-99) in groundwater and to determine their concentrations in groundwater beneath waste management area S-SX. Comments and concerns expressed by the Washington State Department of Ecology on the initial waste management area S-SX assessment report were addressed in the descriptive narrative of this plan as well as in the planned activities. Comment disposition is documented in a separate addendum to this plan

  15. Public consultation of 27 July 2017 no. 2017-012 relating to the creation of a single gas market area in France on 1 November 2018

    International Nuclear Information System (INIS)

    2017-01-01

    This public consultation concerns the operational conditions for the creation of a single gas market area in France on 1 November 2018. It forms part of the road-map towards a single gas market area in France as defined by the CRE in 2012. In order to relieve the existing congestion between the GRTgaz network North and South zones and to enable the creation of a single market area common to GRTgaz and TIGF, the CRE adopted, in its deliberation of 7 May 2014, the investment configuration associating the reinforcement of the Val-de-Saone pipeline and the Gascogne-Midi project. These new infrastructures, developed by GRTgaz and TIGF, have been designed to enable the creation of a single zone at an optimised cost. Consequently, in certain network configurations of use, residual congestions could exceptionally occur. This public consultation proposes the contractual mechanisms planned at this stage to relieve this congestion so as to ensure the availability of firm capacity. In order to define the most relevant mechanisms, the TSOs have studied the occurrence of residual congestion and the solutions that could be implemented to remedy them in the Concertation Gas process since September 2016. At the end of this work, the TSOs submitted a joint proposal to the CRE, which is annexed to this public consultation. In addition, pending the commissioning of new works, and while the 2016-2017 winter was marked by a South-East congestion that resulted in constraints in the nomination of certain players, this public consultation also focuses on the solutions studied by the TSOs in the event that this congestion occurs again in the winter of 2017-2018, as well as the changes in the price of imbalances

  16. Detection of Single Tree Stems in Forested Areas from High Density ALS Point Clouds Using 3d Shape Descriptors

    Science.gov (United States)

    Amiri, N.; Polewski, P.; Yao, W.; Krzystek, P.; Skidmore, A. K.

    2017-09-01

    Airborne Laser Scanning (ALS) is a widespread method for forest mapping and management purposes. While common ALS techniques provide valuable information about the forest canopy and intermediate layers, the point density near the ground may be poor due to dense overstory conditions. The current study highlights a new method for detecting stems of single trees in 3D point clouds obtained from high density ALS with a density of 300 points/m2. Compared to standard ALS data, due to lower flight height (150-200 m) this elevated point density leads to more laser reflections from tree stems. In this work, we propose a three-tiered method which works on the point, segment and object levels. First, for each point we calculate the likelihood that it belongs to a tree stem, derived from the radiometric and geometric features of its neighboring points. In the next step, we construct short stem segments based on high-probability stem points, and classify the segments by considering the distribution of points around them as well as their spatial orientation, which encodes the prior knowledge that trees are mainly vertically aligned due to gravity. Finally, we apply hierarchical clustering on the positively classified segments to obtain point sets corresponding to single stems, and perform ℓ1-based orthogonal distance regression to robustly fit lines through each stem point set. The ℓ1-based method is less sensitive to outliers compared to the least square approaches. From the fitted lines, the planimetric tree positions can then be derived. Experiments were performed on two plots from the Hochficht forest in Oberösterreich region located in Austria.We marked a total of 196 reference stems in the point clouds of both plots by visual interpretation. The evaluation of the automatically detected stems showed a classification precision of 0.86 and 0.85, respectively for Plot 1 and 2, with recall values of 0.7 and 0.67.

  17. Influência da temperatura e do teor de humidade do solo na área foliar e acumulação de matéria seca durante o estabelecimento da ervilha, do milho e do girassol Influence of temperature and soil moisture on leaf area and dry matter accumulation during establishment of pea, maize and sunflower

    Directory of Open Access Journals (Sweden)

    J. A. Andrade

    2007-07-01

    Full Text Available O crescimento foliar e a acumulação de matéria seca durante o estabelecimento da ervilha (Pisum sativum L., var. Ballet, do milho (Zea mays L., var. Lorena e do girassol (Helianthus annuus L., var. Flora-sol foram estudados em função da temperatura e do teor de água num solo Pmg(Évora e num Cb (Lisboa, entre Junho de 1995 e Novembro de 1996. Mediu-se a temperatura do solo a 2 e 4 cm de profundidade, a temperatura do ar e a humidade do solo. A área foliar das plântulas foi estimada a partir de medições do comprimento e da largura de cada folha. A acumulação de matéria seca foi avaliada pela pesagem da parte aérea das plântulas após secagem em estufa. Os dados foram analisados com base no conceito de tempo térmico. Para teores de humidade superiores a 50% da capacidade utilizável de cada solo, a área foliar durante o estabelecimento da ervilha e do milho aumentou linearmente com a temperatura acumulada, enquanto que a do girassol aumentou exponencialmente durante o mesmo período. A relação entre a acumulação de matéria seca de qualquer das culturas e a temperatura acumulada foi exponencial. O tipo de solo influenciou significativamente o “início da expansão foliar” da ervilha e do girassol, a “taxa térmica de expansão foliar” do milho e a acumulação de matéria seca da ervilha e do milho. O “início da expansão foliar” da ervilha ocorreu mais cedo no solo Cb enquanto que o do girassol ocorreu mais cedo no solo Pmg. A expansão foliar do milho foi mais rápida no solo Pmg. A acumulação de matéria seca da ervilha foi mais rápida no solo Cb, enquanto que a do girassol foi mais rápida no solo Pmg. Em ambos os solos, baixos teores de humidade afectaram negativamente a expansão da área foliar e a acumulação de matéria seca.Leaf area expansion and accumulation of dry matter during the establishment of pea (Pisum sativum L., var. Ballet, maize (Zea mays L., var. Lorena and sunflower (Helianthus annuus

  18. LAMINA: a tool for rapid quantification of leaf size and shape parameters

    Directory of Open Access Journals (Sweden)

    Gustafsson Petter

    2008-07-01

    Full Text Available Abstract Background An increased understanding of leaf area development is important in a number of fields: in food and non-food crops, for example short rotation forestry as a biofuels feedstock, leaf area is intricately linked to biomass productivity; in paleontology leaf shape characteristics are used to reconstruct paleoclimate history. Such fields require measurement of large collections of leaves, with resulting conclusions being highly influenced by the accuracy of the phenotypic measurement process. Results We have developed LAMINA (Leaf shApe deterMINAtion, a new tool for the automated analysis of images of leaves. LAMINA has been designed to provide classical indicators of leaf shape (blade dimensions and size (area, which are typically required for correlation analysis to biomass productivity, as well as measures that indicate asymmetry in leaf shape, leaf serration traits, and measures of herbivory damage (missing leaf area. In order to allow Principal Component Analysis (PCA to be performed, the location of a chosen number of equally spaced boundary coordinates can optionally be returned. Conclusion We demonstrate the use of the software on a set of 500 scanned images, each containing multiple leaves, collected from a common garden experiment containing 116 clones of Populus tremula (European trembling aspen that are being used for association mapping, as well as examples of leaves from other species. We show that the software provides an efficient and accurate means of analysing leaf area in large datasets in an automated or semi-automated work flow.

  19. Tradeoff between Stem Hydraulic Efficiency and Mechanical Strength Affects Leaf-Stem Allometry in 28 Ficus Tree Species.

    Science.gov (United States)

    Fan, Ze-Xin; Sterck, Frank; Zhang, Shi-Bao; Fu, Pei-Li; Hao, Guang-You

    2017-01-01

    Leaf-stem allometry is an important spectrum that linked to biomass allocation and life history strategy in plants, although the determinants and evolutionary significance of leaf-stem allometry remain poorly understood. Leaf and stem architectures - including stem area/mass, petiole area/mass, lamina area/mass, leaf number, specific leaf area (LA), and mass-based leafing intensity (LI) - were measured on the current-year branches for 28 Ficus species growing in a common garden in SW China. The leaf anatomical traits, stem wood density (WD), and stem anatomical and mechanical properties of these species were also measured. We analyzed leaf-stem allometric relationships and their associations with stem hydraulic ad mechanical properties using species-level data and phylogenetically independent contrasts. We found isometric relationship between leaf lamina area/mass and stem area/mass, suggesting that the biomass allocation to leaf was independent to stem size. However, allometric relationship between LA/mass and petiole mass was found, indicating large leaves invest a higher fractional of biomass in petiole than small ones. LI, i.e., leaf numbers per unit of stem mass, was negatively related with leaf and stem size. Species with larger terminal branches tend to have larger vessels and theoretical hydraulic conductivity, but lower WD and mechanical strength. The size of leaf lamina, petiole, and stem was correlated positively with stem theoretical hydraulic conductivity, but negatively with stem WD and mechanical strength. Our results suggest that leaf-stem allometry in Ficus species was shaped by the trade-off between stem hydraulic efficiency and mechanical stability, supporting a functional interpretation of the relationship between leaf and stem dimensions.

  20. (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.

  1. 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.

  2. The artificial leaf.

    Science.gov (United States)

    Nocera, Daniel G

    2012-05-15

    To convert the energy of sunlight into chemical energy, the leaf splits water via the photosynthetic process to produce molecular oxygen and hydrogen, which is in a form of separated protons and electrons. The primary steps of natural photosynthesis involve the absorption of sunlight and its conversion into spatially separated electron-hole pairs. The holes of this wireless current are captured by the oxygen evolving complex (OEC) of photosystem II (PSII) to oxidize water to oxygen. The electrons and protons produced as a byproduct of the OEC reaction are captured by ferrodoxin of photosystem I. With the aid of ferrodoxin-NADP(+) reductase, they are used to produce hydrogen in the form of NADPH. For a synthetic material to realize the solar energy conversion function of the leaf, the light-absorbing material must capture a solar photon to generate a wireless current that is harnessed by catalysts, which drive the four electron/hole fuel-forming water-splitting reaction under benign conditions and under 1 sun (100 mW/cm(2)) illumination. This Account describes the construction of an artificial leaf comprising earth-abundant elements by interfacing a triple junction, amorphous silicon photovoltaic with hydrogen- and oxygen-evolving catalysts made from a ternary alloy (NiMoZn) and a cobalt-phosphate cluster (Co-OEC), respectively. The latter captures the structural and functional attributes of the PSII-OEC. Similar to the PSII-OEC, the Co-OEC self-assembles upon oxidation of an earth-abundant metal ion from 2+ to 3+, may operate in natural water at room temperature, and is self-healing. The Co-OEC also activates H(2)O by a proton-coupled electron transfer mechanism in which the Co-OEC is increased by four hole equivalents akin to the S-state pumping of the Kok cycle of PSII. X-ray absorption spectroscopy studies have established that the Co-OEC is a structural relative of Mn(3)CaO(4)-Mn cubane of the PSII-OEC, where Co replaces Mn and the cubane is extended in a

  3. Neighborhood Landscape Spatial Patterns and Land Surface Temperature: An Empirical Study on Single-Family Residential Areas in Austin, Texas

    Science.gov (United States)

    Kim, Jun-Hyun; Gu, Donghwan; Sohn, Wonmin; Kil, Sung-Ho; Kim, Hwanyong; Lee, Dong-Kun

    2016-01-01

    Rapid urbanization has accelerated land use and land cover changes, and generated the urban heat island effect (UHI). Previous studies have reported positive effects of neighborhood landscapes on mitigating urban surface temperatures. However, the influence of neighborhood landscape spatial patterns on enhancing cooling effects has not yet been fully investigated. The main objective of this study was to assess the relationships between neighborhood landscape spatial patterns and land surface temperatures (LST) by using multi-regression models considering spatial autocorrelation issues. To measure the influence of neighborhood landscape spatial patterns on LST, this study analyzed neighborhood environments of 15,862 single-family houses in Austin, Texas, USA. Using aerial photos, geographic information systems (GIS), and remote sensing, FRAGSTATS was employed to calculate values of several landscape indices used to measure neighborhood landscape spatial patterns. After controlling for the spatial autocorrelation effect, results showed that larger and better-connected landscape spatial patterns were positively correlated with lower LST values in neighborhoods, while more fragmented and isolated neighborhood landscape patterns were negatively related to the reduction of LST. PMID:27598186

  4. Neighborhood Landscape Spatial Patterns and Land Surface Temperature: An Empirical Study on Single-Family Residential Areas in Austin, Texas

    Directory of Open Access Journals (Sweden)

    Jun-Hyun Kim

    2016-09-01

    Full Text Available Rapid urbanization has accelerated land use and land cover changes, and generated the urban heat island effect (UHI. Previous studies have reported positive effects of neighborhood landscapes on mitigating urban surface temperatures. However, the influence of neighborhood landscape spatial patterns on enhancing cooling effects has not yet been fully investigated. The main objective of this study was to assess the relationships between neighborhood landscape spatial patterns and land surface temperatures (LST by using multi-regression models considering spatial autocorrelation issues. To measure the influence of neighborhood landscape spatial patterns on LST, this study analyzed neighborhood environments of 15,862 single-family houses in Austin, Texas, USA. Using aerial photos, geographic information systems (GIS, and remote sensing, FRAGSTATS was employed to calculate values of several landscape indices used to measure neighborhood landscape spatial patterns. After controlling for the spatial autocorrelation effect, results showed that larger and better-connected landscape spatial patterns were positively correlated with lower LST values in neighborhoods, while more fragmented and isolated neighborhood landscape patterns were negatively related to the reduction of LST.

  5. Neighborhood Landscape Spatial Patterns and Land Surface Temperature: An Empirical Study on Single-Family Residential Areas in Austin, Texas.

    Science.gov (United States)

    Kim, Jun-Hyun; Gu, Donghwan; Sohn, Wonmin; Kil, Sung-Ho; Kim, Hwanyong; Lee, Dong-Kun

    2016-09-02

    Rapid urbanization has accelerated land use and land cover changes, and generated the urban heat island effect (UHI). Previous studies have reported positive effects of neighborhood landscapes on mitigating urban surface temperatures. However, the influence of neighborhood landscape spatial patterns on enhancing cooling effects has not yet been fully investigated. The main objective of this study was to assess the relationships between neighborhood landscape spatial patterns and land surface temperatures (LST) by using multi-regression models considering spatial autocorrelation issues. To measure the influence of neighborhood landscape spatial patterns on LST, this study analyzed neighborhood environments of 15,862 single-family houses in Austin, Texas, USA. Using aerial photos, geographic information systems (GIS), and remote sensing, FRAGSTATS was employed to calculate values of several landscape indices used to measure neighborhood landscape spatial patterns. After controlling for the spatial autocorrelation effect, results showed that larger and better-connected landscape spatial patterns were positively correlated with lower LST values in neighborhoods, while more fragmented and isolated neighborhood landscape patterns were negatively related to the reduction of LST.

  6. Genetics and mapping of a new leaf rust resistance gene in Triticum ...

    Indian Academy of Sciences (India)

    AMIT KUMAR SINGH

    Selection G12 showed resistance at both seedling and adult plant stages. Genetic analysis in F1, F2 and F2:3 families at the seedling stage revealed that leaf rust resistance in Selection G12 is conditioned by a single incompletely dominant gene. The leaf rust resistance gene was mapped to chromosome 3BL with SSR ...

  7. Identification of leaf rust resistant gene Lr10 in Pakistani wheat ...

    African Journals Online (AJOL)

    Leaf (brown) rust is the major disease of wheat in Pakistan and other countries. The disease is more effectively controlled when several rust resistance genes are pyramided into a single line. Molecular survey was conducted to screen 25 Pakistan wheat germplasm for the presence of leaf rust resistance gene Lr10 using ...

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

    Science.gov (United States)

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

    2013-12-01

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

  9. The worldwide leaf economics spectrum

    NARCIS (Netherlands)

    Wright, I.J.; Reich, P.B.; Westoby, M.; Ackerly, D.D.; Baruch, Z.; Bongers, F.J.J.M.; Cavender-Bares, J.; Chapin, T.; Cornelissen, J.H.C.; Diemer, M.; Flexas, J.; Garnier, E.; Groom, P.K.; Gulias, J.; Hikosaka, K.; Lamont, B.B.; Lee, T.; Lee, W.; Lusk, C.; Midgley, J.J.; Navas, M.L.; Niinements, Ü.; Oleksyn, J.; Osada, N.; Poorter, H.; Poot, P.; Prior, L.; Pyankov, V.I.; Roumet, C.; Thomas, S.C.; Tjoelker, M.G.; Veneklaas, E.J.; Villar, R.

    2004-01-01

    Bringing together leaf trait data spanning 2,548 species and 175 sites we describe, for the first time at global scale, a universal spectrum of leaf economics consisting of key chemical, structural and physiological properties. The spectrum runs from quick to slow return on investments of nutrients

  10. 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. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

  11. Leaf expansion in Phaseolus: transient auxin-induced growth increase

    Science.gov (United States)

    Keller, Christopher P.

    2017-01-01

    Control of leaf expansion by auxin is not well understood. Evidence from short term exogenous applications and from treatment of excised tissues suggests auxin positively influences growth. Manipulations of endogenous leaf auxin content, however, suggests that, long-term, auxin suppresses leaf expansion. This study attempts to clarify the growth effects of auxin on unifoliate (primary) leaves of the common bean (Phaseolus vulgaris) by reexamining the response to auxin treatment of both excised leaf strips and attached leaves. Leaf strips, incubated in culture conditions that promoted steady elongation for up to 48 h, treated with 10 μM NAA responded with an initial surge of elongation growth complete within 10 hours followed by insensitivity. A range of NAA concentrations from 0.1 μM to 300 μM induced increased strip elongation after 24 hours and 48 hours. Increased elongation and epinastic curvature of leaf strips was found specific to active auxins. Expanding attached unifoliates treated once with aqueous auxin α-naphthalene acetic acid (NAA) at 1.0 mM showed both an initial surge in growth lasting 4–6 hours followed by growth inhibition sustained at least as long as 24 hours post treatment. Auxin-induced inhibition of leaf expansion was associated with smaller epidermal cell area. Together the results suggest increasing leaf auxin first increases growth then slows growth through inhibition of cell expansion. Excised leaf strips, retain only the initial increased growth response to auxin and not the subsequent growth inhibition, either as a consequence of wounding or of isolation from the plant. PMID:29200506

  12. Impairment of leaf photosynthesis after insect herbivory or mechanical injury on common milkweed, Asclepias syriaca.

    Science.gov (United States)

    Delaney, K J; Haile, F J; Peterson, R K D; Higley, L G

    2008-10-01

    Insect herbivory has variable consequences on plant physiology, growth, and reproduction. In some plants, herbivory reduces photosynthetic rate (Pn) activity on remaining tissue of injured leaves. We sought to better understand the influence of leaf injury on Pn of common milkweed, Asclepias syriaca (Asclepiadaceae), leaves. Initially, we tested whether Pn reductions occurred after insect herbivory or mechanical injury. We also (1) examined the duration of photosynthetic recovery, (2) compared mechanical injury with insect herbivory, (3) studied the relationship between leaf Pn with leaf injury intensity, and (4) considered uninjured leaf compensatory Pn responses neighboring an injured leaf. Leaf Pn was significantly reduced on mechanically injured or insect-fed leaves in all reported experiments except one, so some factor(s) (cardiac glycoside induction, reproductive investment, and water stress) likely interacts with leaf injury to influence whether Pn impairment occurs. Milkweed tussock moth larval herbivory, Euchaetes egle L. (Arctiidae), impaired leaf Pn more severely than mechanical injury in one experiment. Duration of Pn impairment lasted > 5 d to indicate high leaf Pn sensitivity to injury, but Pn recovery occurred within 13 d in one experiment. The degree of Pn reduction was more severe from E. egle herbivory than similar levels of mechanical tissue removal. Negative linear relationships characterized leaf Pn with percentage tissue loss from single E. egle-fed leaves and mechanically injured leaves and suggested that the signal to trigger leaf Pn impairment on remaining tissue of an injured leaf was amplified by additional tissue loss. Finally, neighboring uninjured leaves to an E. egle-fed leaf had a small (approximately 10%) degree of compensatory Pn to partly offset tissue loss and injured leaf Pn impairment.

  13. Impact of anatomical traits of maize (Zea mays L.) leaf as affected by nitrogen supply and leaf age on bundle sheath conductance.

    Science.gov (United States)

    Retta, Moges; Yin, Xinyou; van der Putten, Peter E L; Cantre, Denis; Berghuijs, Herman N C; Ho, Quang Tri; Verboven, Pieter; Struik, Paul C; Nicolaï, Bart M

    2016-11-01

    The mechanism of photosynthesis in C 4 crops depends on the archetypal Kranz-anatomy. To examine how the leaf anatomy, as altered by nitrogen supply and leaf age, affects the bundle sheath conductance (g bs ), maize (Zea mays L.) plants were grown under three contrasting nitrogen levels. Combined gas exchange and chlorophyll fluorescence measurements were done on fully grown leaves at two leaf ages. The measured data were analysed using a biochemical model of C 4 photosynthesis to estimate g bs . The leaf microstructure and ultrastructure were quantified using images obtained from micro-computed tomography and microscopy. There was a strong positive correlation between g bs and leaf nitrogen content (LNC) while old leaves had lower g bs than young leaves. Leaf thickness, bundle sheath cell wall thickness and surface area of bundle sheath cells per unit leaf area (S b ) correlated well with g bs although they were not significantly affected by LNC. As a result, the increase of g bs with LNC was little explained by the alteration of leaf anatomy. In contrast, the combined effect of LNC and leaf age on S b was responsible for differences in g bs between young leaves and old leaves. Future investigations should consider changes at the level of plasmodesmata and membranes along the CO 2 leakage pathway to unravel LNC and age effects further. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. Groundwater quality assessment plan for single-shell tank waste management Area U at the Hanford Site

    International Nuclear Information System (INIS)

    FN Hodges; CJ Chou

    2000-01-01

    Waste Management Area U (WMA U) includes the U Tank Farm, is currently regulated under RCRA interim-status regulations, and is scheduled for closure probably post-2030. Groundwater monitoring has been under an evaluation program that compared general contaminant indicator parameters from downgradient wells to background values established from upgradient wells. One of the indicator parameters, specific conductance, exceeded its background value in one downgradient well triggering a change from detection monitoring to a groundwater quality assessment program. The objective of the first phase of this assessment program is to determine whether the increased concentrations of nitrate and chromium in groundwater are from WMA U or from an upgradient source. Based on the results of the first determination, if WMA U is not the source of contamination, then the site will revert to detection monitoring. If WMA U is the source, then a second part of the groundwater quality assessment plan will be prepared to define the rate and extent of migration of contaminants in the groundwater and their concentrations

  15. Comparative assessment of the area of sealer voids in single cone obturation done with mineral trioxide aggregate, epoxy resin, and zinc-oxide eugenol based sealers

    Directory of Open Access Journals (Sweden)

    Anisha Kumar

    2016-01-01

    Full Text Available Introduction: Voids in the sealer mass have the potential to allow leakage through obturation. They are more critical in single cone (SC obturation as the volume of sealer used in this obturation is larger when compared to other obturations. Aim: To compare the area of voids in mineral trioxide aggregate (MTA-based, resin-based, and zinc oxide-eugenol-based sealers when employed with SC obturation technique. Materials and Methods: Fifteen teeth were cleaned and shaped and divided into three groups for SC obturation using MTA Fillapex, AH26, and Pulpdent sealers, respectively. The obturated teeth were sectioned at apical, middle, and coronal third, and area of voids in the sealer was assessed using a stereomicroscope and digital images and image software. The results were statistically analyzed using SPSS software and Kruskal-Wallis and Mann-Whitney tests. Results: The three tested sealers showed voids in all the sections except MTA Fillapex, which was void free in apical and middle sections. There were significant differences between these sealers regarding their section wise area of voids (P < 0.05. Similarly, there were significant differences in their overall area of voids (P < 0.05 with MTA Fillapex showing significantly least area of voids followed by AH26. Conclusions: SC obturation with MTA Fillapex sealer, which showed void free apical and middle third sections, had significantly least area of voids in the sealer followed by the one with AH26 sealer, whereas SC obturation with Pulpdent sealer had significantly most area of voids.

  16. Oleaceous laurophyllous leaf fossils and pollen from the European Tertiary.

    Science.gov (United States)

    Sachse, M

    2001-06-01

    By using cuticular analysis for the first time laurophyllous leaf remains from the European Tertiary have been reliably identified as belonging to the Oleaceae. Despite ecologically determined variation in cuticular structures, Late Miocene leaf material from northern Italy is assigned to a single species, Oleinites liguricus Sachse n. sp. The associated oleaceous pollen grains support that this species has been a prominent component, at least locally, of a laurophyllous forest community. From extensive comparisons with leaf cuticles and pollen of extant Oleaceae it may be concluded, that the fossil leaves and probably corresponding pollen represent the tribe Oleeae and may originate from a plant closely comparable to extant Chionanthus and Fraxinus. A reinvestigation of some Oligocene laurophyllous leaf remains has uncovered two more oleaceous species in the European Tertiary: Oleinites maii (Buzek et al.) Sachse comb. nov., and Oleinites hallbaueri (Mai) Sachse comb. nov. Considering the high diversity of laurophyllous Oleaceae in modern evergreen and mixed mesophytic forests and the common presence of oleaceous pollen in the fossil record it may be expected that cuticular analysis of laurophyllous leaf fossils will lead to the recognition of an increased number of oleaceous taxa in Tertiary leaf assemblages.

  17. Carbohydrate as a factor controlling leaf development in cocoa

    Energy Technology Data Exchange (ETDEWEB)

    Machado, R.C.R.

    1986-01-01

    Cocoa shows growth periodicity of the shoot apex where periods of active new leaf development (flushing) alternate with periods of dormancy (Interflush). This thesis presents the results of an investigation into the characteristics of leaf growth, and the production and translocation of photosynthate/carbohydrate between source and sink leaves aimed to investigate the possible role of plant carbohydrate status in the control of the intermittent leaf production. The photosynthetic capacity of mature leaves did not increase during the phase of major increase in carbohydrate consumption by developing leaves but rather decreased slightly. Translocation of assimilated /sup 14/carbon from mature leaves was however significantly increased during phase of rapid expansion of the new leaves. Compensatory changes in the /sup 14/carbon-export from a single remaining source leaf after defoliation showed that mature leaves normally operate much below both their maximum photosynthate loading capacity and export potential. Partial removal of developing leaves within one flush resulted in increased /sup 14/C-photosynthate import into the remaining leaf showing that a developing leaf has a greater import and unloading potential than that utilized during its development in o