WorldWideScience

Sample records for abaxial leaf surfaces

  1. Characterization of photosynthetic gas exchange in leaves under simulated adaxial and abaxial surfaces alternant irradiation.

    Science.gov (United States)

    Zhang, Zi-Shan; Li, Yu-Ting; Gao, Hui-Yuan; Yang, Cheng; Meng, Qing-Wei

    2016-07-05

    Previous investigations on photosynthesis have been performed on leaves irradiated from the adaxial surface. However, leaves usually sway because of wind. This action results in the alternating exposure of both the adaxial and abaxial surfaces to bright sunlight. To simulate adaxial and abaxial surfaces alternant irradiation (ad-ab-alt irradiation), the adaxial or abaxial surface of leaves were exposed to light regimes that fluctuated between 100 and 1,000 μmol m(-2) s(-1). Compared with constant adaxial irradiation, simulated ad-ab-alt irradiation suppressed net photosynthetic rate (Pn) and transpiration (E) but not water use efficiency. These suppressions were aggravated by an increase in alternant frequency of the light intensity. When leaves were transferred from constant light to simulated ad-ab-alt irradiation, the maximum Pn and E during the high light period decreased, but the rate of photosynthetic induction during this period remained constant. The sensitivity of photosynthetic gas exchange to simulated ad-ab-alt irradiation was lower on abaxial surface than adaxial surface. Under simulated ad-ab-alt irradiation, higher Pn and E were measured on abaxial surface compared with adaxial surface. Therefore, bifacial leaves can fix more carbon than leaves with two "sun-leaf-like" surfaces under ad-ab-alt irradiation. Photosynthetic research should be conducted under dynamic conditions that better mimic nature.

  2. Abaxial growth and steric constraints guide leaf folding and shape in Acer pseudoplatanus.

    Science.gov (United States)

    Couturier, Etienne; Brunel, Nicole; Douady, Stéphane; Nakayama, Naomi

    2012-08-01

    How leaf shape is regulated is a long-standing question in botany. For diverse groups of dicotyledon species, lamina folding along the veins and geometry of the space available for the primordia can explain the palmate leaf morphology. Dubbed the kirigami theory, this hypothesis of fold-dependent leaf shape regulation has remained largely theoretical. Using Acer pseudoplatanus, we investigated the mechanisms behind the two key processes of kirigami leaf development. Cytological examination and quantitative analyses were used to examine the course of the vein-dependent lamina folding. Surgical ablation and tissue culturing were employed to test the effects of physical constraints on primordia growth. The final morphology of leaves growing without steric constraints were predicted mathematically. The cytological examination showed that the lamina's abaxial side along the veins grows substantially more than the adaxial side. The abaxial hypergrowth along the veins and the lamina extension correlated with the lamina folding. When a primordium was released from the physical constraints imposed by the other primordia, it rapidly grew into the newly available space, while maintaining the curvature inward. The morphology of such a leaf was predicted to lack symmetry in the lobe shapes. The enhanced growth on the abaxial side of the lamina along the veins is likely to drive lamina folding. The surgical ablation provided clear support for the space-filling nature of leaf growth; thus, steric constraints play a role in determination of the shapes of folded leaves and probably also of the final leaf morphology.

  3. Genetic Variation and Divergence of Genes Involved in Leaf Adaxial-abaxial Polarity Establishment in Brassica rapa

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    Jianli eLiang

    2016-02-01

    Full Text Available Alterations in leaf adaxial–abaxial (ad-ab polarity are one of the main factors that are responsible for leaf curvature. In Chinese cabbage, to form a leafy head, leaf incurvature is an essential prerequisite. Identifying ad-ab patterning genes and investigating its genetic variations will facilitate in elucidating the mechanism underlying leaf incurvature during head formation. In the present study we conducted comparative genomic analysis of the identification of 45 leaf ad-ab patterning genes in Brassica rapa based on 26 homologs in Arabidopsis thaliana, indicating that these genes underwent expansion and were retained after whole genome triplication (WGT. We also assessed the nucleotide diversity and selection footprints of these 45 genes in a collection of 94 Brassica rapa accessions that were composed of heading and non-heading morphotypes. Six of the 45 genes showed significant negative Tajima’s D indices and nucleotide diversity reduction in heading accessions compared to that in non-heading accessions, indicating that these underwent purifying selection. Further testing of the BrARF3.1 gene, which was one of the selection signals from a larger collection, confirmed that purifying selection did occur. Our results provide genetic evidence that ad-ab patterning genes are involved in leaf incurvature that is associated in the formation of a leafy head, as well as promote an understanding of the genetic mechanism underlying leafy head formation in Chinese cabbage.

  4. SlLAX1 is Required for Normal Leaf Development Mediated by Balanced Adaxial and Abaxial Pavement Cell Growth in Tomato.

    Science.gov (United States)

    Pulungan, Sri Imriani; Yano, Ryoichi; Okabe, Yoshihiro; Ichino, Takuji; Kojima, Mikiko; Takebayashi, Yumiko; Sakakibara, Hitoshi; Ariizumi, Tohru; Ezura, Hiroshi

    2018-06-01

    Leaves are the major plant organs with a primary function for photosynthesis. Auxin controls various aspects of plant growth and development, including leaf initiation, expansion and differentiation. Unique and intriguing auxin features include its polar transport, which is mainly controlled by the AUX1/LAX and PIN gene families as influx and efflux carriers, respectively. The role of AUX1/LAX genes in root development is well documented, but the role of these genes in leaf morphogenesis remains unclear. Moreover, most studies have been conducted in the plant model Arabidopsis thaliana, while studies in tomato are still scarce. In this study, we isolated six lines of the allelic curly leaf phenotype 'curl' mutants from a γ-ray and EMS (ethyl methanesulfonate) mutagenized population. Using a map-based cloning strategy combined with exome sequencing, we observed that a mutation occurred in the SlLAX1 gene (Solyc09g014380), which is homologous to an Arabidopsis auxin influx carrier gene, AUX1 (AtAUX1). Characterization of six alleles of single curl mutants revealed the pivotal role of SlLAX1 in controlling tomato leaf flatness by balancing adaxial and abaxial pavement cell growth, which has not been reported in tomato. Using TILLING (Targeting Induced Local Lesions IN Genome) technology, we isolated an additional mutant allele of the SlLAX1 gene and this mutant showed a curled leaf phenotype similar to other curl mutants, suggesting that Solyc09g014380 is responsible for the curl phenotype. These results showed that SlLAX1 is required for normal leaf development mediated by balanced adaxial and abaxial pavement cell growth in tomato.

  5. Two Nucleolar Proteins, GDP1 and OLI2, Function As Ribosome Biogenesis Factors and Are Preferentially Involved in Promotion of Leaf Cell Proliferation without Strongly Affecting Leaf Adaxial–Abaxial Patterning in Arabidopsis thaliana

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    Koji Kojima

    2018-01-01

    Full Text Available Leaf abaxial–adaxial patterning is dependent on the mutual repression of leaf polarity genes expressed either adaxially or abaxially. In Arabidopsis thaliana, this process is strongly affected by mutations in ribosomal protein genes and in ribosome biogenesis genes in a sensitized genetic background, such as asymmetric leaves2 (as2. Most ribosome-related mutants by themselves do not show leaf abaxialization, and one of their typical phenotypes is the formation of pointed rather than rounded leaves. In this study, we characterized two ribosome-related mutants to understand how ribosome biogenesis is linked to several aspects of leaf development. Previously, we isolated oligocellula2 (oli2 which exhibits the pointed-leaf phenotype and has a cell proliferation defect. OLI2 encodes a homolog of Nop2 in Saccharomyces cerevisiae, a ribosome biogenesis factor involved in pre-60S subunit maturation. In this study, we found another pointed-leaf mutant that carries a mutation in a gene encoding an uncharacterized protein with a G-patch domain. Similar to oli2, this mutant, named g-patch domain protein1 (gdp1, has a reduced number of leaf cells. In addition, gdp1 oli2 double mutants showed a strong genetic interaction such that they synergistically impaired cell proliferation in leaves and produced markedly larger cells. On the other hand, they showed additive phenotypes when combined with several known ribosomal protein mutants. Furthermore, these mutants have a defect in pre-rRNA processing. GDP1 and OLI2 are strongly expressed in tissues with high cell proliferation activity, and GDP1-GFP and GFP-OLI2 are localized in the nucleolus. These results suggest that OLI2 and GDP1 are involved in ribosome biogenesis. We then examined the effects of gdp1 and oli2 on adaxial–abaxial patterning by crossing them with as2. Interestingly, neither gdp1 nor oli2 strongly enhanced the leaf polarity defect of as2. Similar results were obtained with as2 gdp1 oli2

  6. Leaf surface anatomy in some woody plants from northeastern Mexico

    International Nuclear Information System (INIS)

    Maiti, R.; Rodriguez, H.G.; Balboa, P.C.R.; Kumari, A

    2016-01-01

    Studies on leaf surface anatomy of woody plants and its significance are rare. The present study was undertaken in the Forest Science Faculty Experimental Research Station, UANL, Mexico, with objectives to determine the variability in leaf surface anatomy in the woody plants of the Tamaulipan thornscrub and its utility in taxonomy and possible adaptation to the prevailing semiarid conditions. The results show the presence of large variability in several leaf anatomical traits viz., waxy leaf surface, type of stomata, its size, and distribution. The species have been classified on the basis of various traits which can be used in species delimitation and adaptation to the semiarid condition such as waxy leaf surface, absence sparse stomata on the leaf surface, sunken stomata. The species identified as better adapters to semi-arid environments on the basis of the presence and absence of stomata on both adaxial and abaxial surface viz., Eysenhardtia texana, Parkinsonia texana, Gymnosperma glutinosum, Celtis laevigata, Condalia hookeri and Karwinskia humboldtiana. (author)

  7. Micromorphology of leaf surface of Coelogyne Lindl. species (Orchidaceae Juss. in greenhouse conditions

    Directory of Open Access Journals (Sweden)

    Alexander G. Gyrenko

    2013-04-01

    Full Text Available The micromorphological characteristics of both adaxial and abaxial leaf surfaces of the plants of five Coelogyne Lindl. species (C. assamicaLinden & Rchb.f., C. brachyptera Rchb.f., C. cumingii Lindl., C. fimbriataLindl., C. lentiginosaLindl. under glasshouse conditions have been described.

  8. 7 CFR 29.3528 - Leaf surface.

    Science.gov (United States)

    2010-01-01

    ... INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf...

  9. The milkweed pod1 gene encodes a KANADI protein that is required for abaxial/adaxial patterning in maize leaves.

    Science.gov (United States)

    Candela, Héctor; Johnston, Robyn; Gerhold, Abigail; Foster, Toshi; Hake, Sarah

    2008-08-01

    Leaf primordia initiate from the shoot apical meristem with inherent polarity; the adaxial side faces the meristem, while the abaxial side faces away from the meristem. Adaxial/abaxial polarity is thought to be necessary for laminar growth of leaves, as mutants lacking either adaxial or abaxial cell types often develop radially symmetric lateral organs. The milkweed pod1 (mwp1) mutant of maize (Zea mays) has adaxialized sectors in the sheath, the proximal part of the leaf. Ectopic leaf flaps develop where adaxial and abaxial cell types juxtapose. Ectopic expression of the HD-ZIPIII gene rolled leaf1 (rld1) correlates with the adaxialized regions. Cloning of mwp1 showed that it encodes a KANADI transcription factor. Double mutants of mwp1-R with a microRNA-resistant allele of rld1, Rld1-N1990, show a synergistic phenotype with polarity defects in sheath and blade and a failure to differentiate vascular and photosynthetic cell types in the adaxialized sectors. The sectored phenotype and timing of the defect suggest that mwp1 is required late in leaf development to maintain abaxial cell fate. The phenotype of mwp1; Rld1 double mutants shows that both genes are also required early in leaf development to delineate leaf margins as well as to initiate vascular and photosynthetic tissues.

  10. The milkweed pod1 Gene Encodes a KANADI Protein That Is Required for Abaxial/Adaxial Patterning in Maize Leaves[W

    Science.gov (United States)

    Candela, Héctor; Johnston, Robyn; Gerhold, Abigail; Foster, Toshi; Hake, Sarah

    2008-01-01

    Leaf primordia initiate from the shoot apical meristem with inherent polarity; the adaxial side faces the meristem, while the abaxial side faces away from the meristem. Adaxial/abaxial polarity is thought to be necessary for laminar growth of leaves, as mutants lacking either adaxial or abaxial cell types often develop radially symmetric lateral organs. The milkweed pod1 (mwp1) mutant of maize (Zea mays) has adaxialized sectors in the sheath, the proximal part of the leaf. Ectopic leaf flaps develop where adaxial and abaxial cell types juxtapose. Ectopic expression of the HD-ZIPIII gene rolled leaf1 (rld1) correlates with the adaxialized regions. Cloning of mwp1 showed that it encodes a KANADI transcription factor. Double mutants of mwp1-R with a microRNA-resistant allele of rld1, Rld1-N1990, show a synergistic phenotype with polarity defects in sheath and blade and a failure to differentiate vascular and photosynthetic cell types in the adaxialized sectors. The sectored phenotype and timing of the defect suggest that mwp1 is required late in leaf development to maintain abaxial cell fate. The phenotype of mwp1; Rld1 double mutants shows that both genes are also required early in leaf development to delineate leaf margins as well as to initiate vascular and photosynthetic tissues. PMID:18757553

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

    Science.gov (United States)

    Burkhardt, Juergen; Hunsche, Mauricio

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Jürgen eBurkhardt

    2013-10-01

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

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

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    Ladawan Rattanapolsan

    2013-07-01

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

  14. Do Aphids Alter Leaf Surface Temperature Patterns During Early Infestation?

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    Thomas Cahon

    2018-03-01

    Full Text Available Arthropods at the surface of plants live in particular microclimatic conditions that can differ from atmospheric conditions. The temperature of plant leaves can deviate from air temperature, and leaf temperature influences the eco-physiology of small insects. The activity of insects feeding on leaf tissues, may, however, induce changes in leaf surface temperatures, but this effect was only rarely demonstrated. Using thermography analysis of leaf surfaces under controlled environmental conditions, we quantified the impact of presence of apple green aphids on the temperature distribution of apple leaves during early infestation. Aphids induced a slight change in leaf surface temperature patterns after only three days of infestation, mostly due to the effect of aphids on the maximal temperature that can be found at the leaf surface. Aphids may induce stomatal closure, leading to a lower transpiration rate. This effect was local since aphids modified the configuration of the temperature distribution over leaf surfaces. Aphids were positioned at temperatures near the maximal leaf surface temperatures, thus potentially experiencing the thermal changes. The feedback effect of feeding activity by insects on their host plant can be important and should be quantified to better predict the response of phytophagous insects to environmental changes.

  15. Bacterial anoxygenic photosynthesis on plant leaf surfaces.

    Science.gov (United States)

    Atamna-Ismaeel, Nof; Finkel, Omri; Glaser, Fabian; von Mering, Christian; Vorholt, Julia A; Koblížek, Michal; Belkin, Shimshon; Béjà, Oded

    2012-04-01

    The aerial surface of plants, the phyllosphere, is colonized by numerous bacteria displaying diverse metabolic properties that enable their survival in this specific habitat. Recently, we reported on the presence of microbial rhodopsin harbouring bacteria on the top of leaf surfaces. Here, we report on the presence of additional bacterial populations capable of harvesting light as a means of supplementing their metabolic requirements. An analysis of six phyllosphere metagenomes revealed the presence of a diverse community of anoxygenic phototrophic bacteria, including the previously reported methylobacteria, as well as other known and unknown phototrophs. The presence of anoxygenic phototrophic bacteria was also confirmed in situ by infrared epifluorescence microscopy. The microscopic enumeration correlated with estimates based on metagenomic analyses, confirming both the presence and high abundance of these microorganisms in the phyllosphere. Our data suggest that the phyllosphere contains a phylogenetically diverse assemblage of phototrophic species, including some yet undescribed bacterial clades that appear to be phyllosphere-unique. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  16. Adaxial/abaxial specification in the regulation of photosynthesis and stomatal opening with respect to light orientation and growth with CO2 enrichment in the C4 species Paspalum dilatatum.

    Science.gov (United States)

    Soares, Ana Sofia; Driscoll, Simon P; Olmos, Enrique; Harbinson, Jeremy; Arrabaça, Maria Celeste; Foyer, Christine H

    2008-01-01

    Whole-plant morphology, leaf structure and composition were studied together with the effects of light orientation on the dorso-ventral regulation of photosynthesis and stomatal conductance in Paspalum dilatatum cv. Raki plants grown for 6 wk at either 350 or 700 microl l(-1) CO(2). Plant biomass was doubled as a result of growth at high CO(2) and the shoot:root ratio was decreased. Stomatal density was increased in the leaves of the high CO(2)-grown plants, which had greater numbers of smaller stomata and more epidermal cells on the abaxial surface. An asymmetric surface-specific regulation of photosynthesis and stomatal conductance was observed with respect to light orientation. This was not caused by dorso-ventral variations in leaf structure, the distribution of phosphoenolpyruvate carboxylase (PEPC) and ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) proteins or light absorptance, transmittance or reflectance. Adaxial/abaxial specification in the regulation of photosynthesis results from differential sensitivity of stomatal opening to light orientation and fixed gradients of enzyme activation across the leaf.

  17. Micro- and nanoscale characterization of hydrophobic and hydrophilic leaf surfaces

    International Nuclear Information System (INIS)

    Bhushan, Bharat; Jung, Yong Chae

    2006-01-01

    Superhydrophobic surfaces as well as low adhesion and friction are desirable for various industrial applications. Certain plant leaves are known to be hydrophobic in nature due to their roughness and the presence of a thin wax film on the surface of the leaf. The purpose of this study is to fully characterize the leaf surfaces on the micro- and nanoscale while separating out the effects of the micro- and the nanobumps of hydrophobic leaves on the hydrophobicity. Hydrophilic leaves were also studied to better understand the role of wax and roughness. Furthermore, the adhesion and friction properties of hydrophobic and hydrophilic leaves were studied. Using an optical profiler and an atomic/friction force microscope (AFM/FFM), measurements were made to fully characterize the leaf surfaces. It is shown that the nanobumps play a more important role than the microbumps in the hydrophobic nature as well as friction of the leaf. This study will be useful in developing superhydrophobic surfaces

  18. Oviposition behavior of the silver leaf whitefly Bemisia tabaci biotype B on tomato

    International Nuclear Information System (INIS)

    Vendramim, Jose D.; Souza, Antonio P. de; Ongarelli, Maria das G.

    2009-01-01

    The objective of this work was to evaluate the influence of the leaf surface, the insect geotropic behavior and the type of foliar trichome on Bemisia tabaci (Genn.) biotype B oviposition on tomato leaves. Bemisia tabaci females were confined in acrylic boxes in which tomato leaflets were fixed at the bottom and top part of the boxes to allow insects to access the leaf surface to be tested (adaxial and/or abaxial) in both no-choice and free choice tests. Oviposition was always higher when the leaf was offered at the top of the box and preferably at the abaxial leaf surface. The effects of leaf trichomes (glandular and non glandular) on B. tabaci oviposition was evaluated by offering the abaxial surface of tomato leaflets to females after a 70% ethanol wash to remove glandular exsudates against a control treatment (without a ethanol wash). Oviposition was concentrated mostly near to non glandular trichomes, showing whitefly females can discriminate among the trichomes. (author)

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

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    Justin Fiene

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

  20. Leaf-morphology-assisted selection for resistance to two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) in carnations (Dianthus caryophyllus L).

    Science.gov (United States)

    Seki, Kousuke

    2016-10-01

    The development of a cultivar resistant to the two-spotted spider mite has provided both ecological and economic benefits to the production of cut flowers. This study aimed to clarify the mechanism of resistance to mites using an inbred population of carnations. In the resistant and susceptible plants selected from an inbred population, a difference was recognised in the thickness of the abaxial palisade tissue by microscopic examination of the damaged leaf. Therefore, it was assumed that mites displayed feeding preferences within the internal leaf structure of the carnation leaf. The suitability of the host plant for mites was investigated using several cultivars selected using an index of the thickness from the abaxial leaf surface to the spongy tissue. The results suggested that the cultivar associated with a thicker abaxial tissue lowered the intrinsic rate of natural increase of the mites. The cultivars with a thicker abaxial tissue of over 120 µm showed slight damage in the field test. The ability of mites to feed on the spongy tissue during an early life stage from hatching to adult emergence was critical. It was possible to select a cultivar that is resistant to mites under a real cultivation environment by observing the internal structure of the leaf. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  1. Analysis of leaf surfaces using scanning ion conductance microscopy.

    Science.gov (United States)

    Walker, Shaun C; Allen, Stephanie; Bell, Gordon; Roberts, Clive J

    2015-05-01

    Leaf surfaces are highly complex functional systems with well defined chemistry and structure dictating the barrier and transport properties of the leaf cuticle. It is a significant imaging challenge to analyse the very thin and often complex wax-like leaf cuticle morphology in their natural state. Scanning electron microscopy (SEM) and to a lesser extent Atomic force microscopy are techniques that have been used to study the leaf surface but their remains information that is difficult to obtain via these approaches. SEM is able to produce highly detailed and high-resolution images needed to study leaf structures at the submicron level. It typically operates in a vacuum or low pressure environment and as a consequence is generally unable to deal with the in situ analysis of dynamic surface events at submicron scales. Atomic force microscopy also possess the high-resolution imaging required and can follow dynamic events in ambient and liquid environments, but can over exaggerate small features and cannot image most leaf surfaces due to their inherent roughness at the micron scale. Scanning ion conductance microscopy (SICM), which operates in a liquid environment, provides a potential complementary analytical approach able to address these issues and which is yet to be explored for studying leaf surfaces. Here we illustrate the potential of SICM on various leaf surfaces and compare the data to SEM and atomic force microscopy images on the same samples. In achieving successful imaging we also show that SICM can be used to study the wetting of hydrophobic surfaces in situ. This has potentially wider implications than the study of leaves alone as surface wetting phenomena are important in a range of fundamental and applied studies. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  2. Do leaf surface characteristics affect Agrobacterium infection in tea

    Indian Academy of Sciences (India)

    The host range specificity of Agrobacterium with five tea cultivars and an unrelated species (Artemisia parviflora) having extreme surface characteristics was evaluated in the present study. The degree of Agrobacterium infection in the five cultivars of tea was affected by leaf wetness, micro-morphology and surface chemistry.

  3. [PS II photochemical efficiency in flag leaf of wheat varieties and its adaptation to strong sun- light intensity on farmland of Xiangride in Qinghai Province, Northwest China].

    Science.gov (United States)

    Shi, Sheng-Bo; Chen, Wen-Jie; Shi, Rui; Li, Miao; Zhang, Huai-Gang; Sun, Ya-Nan

    2014-09-01

    Taking four wheat varieties developed by Northwest Institute of Plateau Biology, Chinese Academy of Sciences, as test materials, with the measurement of content of photosynthetic pigments, leaf area, fresh and dry mass of flag leaf, the PS II photochemistry efficiency of abaxial and adaxial surface of flag leaf and its adaptation to strong solar radiation during the period of heading stage in Xiangride region were investigated with the pulse-modulated in-vivo chlorophyll fluorescence technique. The results indicated that flag leaf angle mainly grew in horizontal state in Gaoyuan 314, Gaoyuan 363 and Gaoyuan 584, and mainly in vertical state in Gaoyuan 913 because of its smaller leaf area and larger width. Photosynthetic pigments were different among the 4 varieties, and positively correlated with intrinsic PS II photochemistry efficiencies (Fv/Fm). In clear days, especially at noon, the photosynthetic photoinhibition was more serious in abaxial surface of flag leaf due to directly facing the solar radiation, but it could recover after reduction of sunlight intensity in the afternoon, which meant that no inactive damage happened in PS II reaction centers. There were significant differences of PS II actual and maximum photochemical efficiencies at the actinic light intensity (ΦPS II and Fv'/Fm') between abaxial and adaxial surface, and their relative variation trends were on the contrary. The photochemical and non-photochemical quenching coefficients (qP and NPQ) had a similar tendency in both abaxial and adaxial surfaces. Although ΦPS II and qP were lower in adaxial surface of flag leaf, the Fv'/Fm' was significantly higher, which indicated that the potential PS II capture efficiency of excited energy was higher. The results demonstrated that process of photochemical and non-photochemical quenching could effectively dissipate excited energy caused by strong solar radiation, and there were higher adaptation capacities in wheat varieties natively cultivated in

  4. LEAF SURFACE COMPARISON OF THREE GENERA OF ARACEAE IN INDONESIA

    Directory of Open Access Journals (Sweden)

    Ina Erlinawati

    2013-07-01

    Full Text Available Alocasia, Colocasia and Remusatia are the genera of Araceae family which have high economic value, such as for food and ornamental plants. Those three genera, previously treated as Colocasieae tribe. Later, based on Nauheimer, L. et al. study in 2012, using plastid and nuclear DNA, Alocasia is placed in different tribe. Study on leaf anatomy of Araceae is still poor known. Comparison of three genera of Araceae, indicates a difference in the epidermis. Alocasia and Colocasia have stomata on both leaf surfaces (amphistomatic but Remusatia has stomata only limited on the lower surface. The three genera can be distinguished from epidermal cell shape, stomata complex and the presence of stomata.

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

    Science.gov (United States)

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

    2016-10-01

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

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

    International Nuclear Information System (INIS)

    Elagoez, Vahram; Han, Susan S.; Manning, William J.

    2006-01-01

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

  7. 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.

  8. Transcuticular translocation of radionuclides on plant leaf surfaces

    International Nuclear Information System (INIS)

    Matsumoto, Ken-ichi; Watanabe, Tadakazu; Ambe, Shizuko; Yamaguchi, Isamu

    1996-01-01

    The cuticle covering all the outermost surfaces of the aerial parts of plants could play a selective role in uptake and translocation of radionuclides from air into plants. In this study, we investigated the transcuticular uptake and translocation behavior via water droplets of various radionuclides in red clover, orchard grass, Japanese radish and mung bean. Ten μl of an aqueous solution of the multitracer generated from Au was applied to the upper surface of the 2nd leaf of the plants at the 5th leaf stage. The plants were then grown for 14 days at 25degC and 70% RH under illumination of artificial solar lights. The transcuticular uptake and translocation throughout the plant were periodically assayed by determining the radioactivity in the surface residue, the cuticle layer beneath the applied site, the leaf area outside the applied site, the other aerial parts and the root of the plant, using an HPGe detector. The applied radionuclides were absorbed into, in turn, the cuticle layer beneath the applied site and then translocated through the cuticle to the inner tissue and eventually to the other aerial parts and finally to the roots, of the plant. The distribution and accumulation in the plant seems to depend upon the characteristics of each radionuclide and plant species. Ca * and Te * tended to remain on leaf surfaces without being absorbed into the cuticle. On the other hand, Sc * , Co * , Zn * , Se * , Rb * , and Eu * were easily absorbed and translocated to every part of the plant including the root. The other radionuclides such as Be * , Mn * , Sr * , Y * , Ba * , Ce * , Pm * , Gd * , Hf * , Yb * , Lu * , Os * , Ir * , and Pt * remained in the region close to the site of their application. The above results possibly indicate the existence of mechanisms common to these plants for selective transcuticular uptake and translocation of radionuclides within plant tissues, though their translocation was considerably influenced by the plant species. (author)

  9. Oviposition behavior of the silver leaf whitefly Bemisia tabaci biotype B on tomato; Comportamento de oviposicao da mosca-branca Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae) biotipo B em tomateiro

    Energy Technology Data Exchange (ETDEWEB)

    Vendramim, Jose D. [Universidade de Sao Paulo (USP), Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Dept. de Entomologia, Fitopatologia e Zoologia Agricola]. E-mail: jdvendra@esalq.usp.br; Souza, Antonio P. de [Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, MS (Brazil). Dept. de Morfofisiologia. Lab. de Anatomia Humana]. E-mail: apsouza@nin.ufms.br; Ongarelli, Maria das G. [Universidade de Sao Paulo (USP), Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Lab. de Fisiologia e Bioquimica Pos-Colheita]. E-mail: mgong@esalq.usp.br

    2009-01-15

    The objective of this work was to evaluate the influence of the leaf surface, the insect geotropic behavior and the type of foliar trichome on Bemisia tabaci (Genn.) biotype B oviposition on tomato leaves. Bemisia tabaci females were confined in acrylic boxes in which tomato leaflets were fixed at the bottom and top part of the boxes to allow insects to access the leaf surface to be tested (adaxial and/or abaxial) in both no-choice and free choice tests. Oviposition was always higher when the leaf was offered at the top of the box and preferably at the abaxial leaf surface. The effects of leaf trichomes (glandular and non glandular) on B. tabaci oviposition was evaluated by offering the abaxial surface of tomato leaflets to females after a 70% ethanol wash to remove glandular exsudates against a control treatment (without a ethanol wash). Oviposition was concentrated mostly near to non glandular trichomes, showing whitefly females can discriminate among the trichomes. (author)

  10. Comparative morphology of leaf epidermis in eight populations of Atlas Pistachio (Pistacia atlantica Desf., Anacardiaceae).

    Science.gov (United States)

    Belhadj, Safia; Derridj, Arezki; Aigouy, Thierry; Gers, Charles; Gauquelin, Thierry; Mevy, Jean-Philippe

    2007-10-01

    A comparative analysis was undertaken to conduct a micromorphological study of Pistacia atlantica leaves by comparing different populations grown under different climatic conditions. Leaf epidermis of eight wild populations was investigated under scanning electron microscope. Micromorphological characteristics (epidermis ornament, stomata type, waxes as well as trichomes) of the adaxial and abaxial leaf surfaces were examined. The epidermis ornament varied among populations and leaf surface, the abaxial leaf surface is reticulate with a striate surface. Messaad site shows a smooth uneven surface. The adaxial leaf surface is smooth but several ornamentations can be seen. The leaflet is amphistomatic; the stomata appeared to be slightly sunken. A variety of stomatal types were recorded; actinocytic and anomocytic types are the most frequent. The indumentum consisted of glandular and nonglandular trichomes. Unicellular glandular trichomes are recorded for P. atlantica leaves in this study. Their density is higher in Oued safene site, located at the highest altitude in comparison with the other populations. The wax occurred in all the sites and its pattern varied according to the populations studied, particularly between Berriane and Messaad. The morphological variability exhibited by the eight populations of P. atlantica may be interpreted as relevant to the ecological plasticity and the physiological mechanisms involved are discussed in this report.

  11. Transcuticular translocation of radionuclides on plant leaf surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Ken-ichi; Watanabe, Tadakazu; Ambe, Shizuko; Yamaguchi, Isamu [Institute of Physical and Chemical Research, Wako, Saitama (Japan)

    1996-12-31

    The cuticle covering all the outermost surfaces of the aerial parts of plants could play a selective role in uptake and translocation of radionuclides from air into plants. In this study, we investigated the transcuticular uptake and translocation behavior via water droplets of various radionuclides in red clover, orchard grass, Japanese radish and mung bean. Ten {mu}l of an aqueous solution of the multitracer generated from Au was applied to the upper surface of the 2nd leaf of the plants at the 5th leaf stage. The plants were then grown for 14 days at 25degC and 70% RH under illumination of artificial solar lights. The transcuticular uptake and translocation throughout the plant were periodically assayed by determining the radioactivity in the surface residue, the cuticle layer beneath the applied site, the leaf area outside the applied site, the other aerial parts and the root of the plant, using an HPGe detector. The applied radionuclides were absorbed into, in turn, the cuticle layer beneath the applied site and then translocated through the cuticle to the inner tissue and eventually to the other aerial parts and finally to the roots, of the plant. The distribution and accumulation in the plant seems to depend upon the characteristics of each radionuclide and plant species. Ca{sup *} and Te{sup *} tended to remain on leaf surfaces without being absorbed into the cuticle. On the other hand, Sc{sup *}, Co{sup *}, Zn{sup *}, Se{sup *}, Rb{sup *}, and Eu{sup *} were easily absorbed and translocated to every part of the plant including the root. The other radionuclides such as Be{sup *}, Mn{sup *}, Sr{sup *}, Y{sup *}, Ba{sup *}, Ce{sup *}, Pm{sup *}, Gd{sup *}, Hf{sup *}, Yb{sup *}, Lu{sup *}, Os{sup *}, Ir{sup *}, and Pt{sup *} remained in the region close to the site of their application. The above results possibly indicate the existence of mechanisms common to these plants for selective transcuticular uptake and translocation of radionuclides within plant

  12. Effect of solution and leaf surface polarity on droplet spread area and contact angle.

    Science.gov (United States)

    Nairn, Justin J; Forster, W Alison; van Leeuwen, Rebecca M

    2016-03-01

    How much an agrochemical spray droplet spreads on a leaf surface can significantly influence efficacy. This study investigates the effect solution polarity has on droplet spreading on leaf surfaces and whether the relative leaf surface polarity, as quantified using the wetting tension dielectric (WTD) technique, influences the final spread area. Contact angles and spread areas were measured using four probe solutions on 17 species. Probe solution polarity was found to affect the measured spread area and the contact angle of the droplets on non-hairy leaves. Leaf hairs skewed the spread area measurement, preventing investigation of the influence of surface polarity on hairy leaves. WTD-measured leaf surface polarity of non-hairy leaves was found to correlate strongly with the effect of solution polarity on spread area. For non-polar leaf surfaces the spread area decreases with increasing solution polarity, for neutral surfaces polarity has no effect on spread area and for polar leaf surfaces the spread area increases with increasing solution polarity. These results attest to the use of the WTD technique as a means to quantify leaf surface polarity. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  13. What's So Bad about Being Wet All Over: Investigating Leaf Surface Wetness.

    Science.gov (United States)

    Brewer, Carol A.

    1996-01-01

    Presents investigations of leaf surface wetness that provide ideal opportunities for students to explore the relationships between leaf form and function, to study surface conditions of leaves and plant physiology, and to make predictions about plant adaptation in different environments. Describes simple procedures for exploring questions related…

  14. Quantitative study of Xanthosoma violaceum leaf surfaces using RIMAPS and variogram techniques.

    Science.gov (United States)

    Favret, Eduardo A; Fuentes, Néstor O; Molina, Ana M

    2006-08-01

    Two new imaging techniques (rotated image with maximum averaged power spectrum (RIMAPS) and variogram) are presented for the study and description of leaf surfaces. Xanthosoma violaceum was analyzed to illustrate the characteristics of both techniques. Both techniques produce a quantitative description of leaf surface topography. RIMAPS combines digitized images rotation with Fourier transform, and it is used to detect patterns orientation and characteristics of surface topography. Variogram relates the mathematical variance of a surface with the area of the sample window observed. It gives the typical scale lengths of the surface patterns. RIMAPS detects the morphological variations of the surface topography pattern between fresh and dried (herbarium) samples of the leaf. The variogram method finds the characteristic dimensions of the leaf microstructure, i.e., cell length, papillae diameter, etc., showing that there are not significant differences between dry and fresh samples. The results obtained show the robustness of RIMAPS and variogram analyses to detect, distinguish, and characterize leaf surfaces, as well as give scale lengths. Both techniques are tools for the biologist to study variations of the leaf surface when different patterns are present. The use of RIMAPS and variogram opens a wide spectrum of possibilities by providing a systematic, quantitative description of the leaf surface topography.

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

    Science.gov (United States)

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

    2017-04-01

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

  16. Relationship between Leaf Surface Characteristics and Particle Capturing Capacities of Different Tree Species in Beijing

    Directory of Open Access Journals (Sweden)

    Weikang Zhang

    2017-03-01

    Full Text Available Leaf surface is a multifunctional interface between a plant and its environment, which affects both ecological and biological processes. Leaf surface topography directly affects microhabitat availability and ability for deposition. In this study, atomic force microscopy (AFM and the resuspended particulate matter method were applied to evaluate the adsorptive capacity of the leaf surface. Patterns of particulate‐capturing capacities in different tree species and the effect of leaf surface features on these capacities were explored. Results indicated the following: (1 more total suspended particles (TSP per unit leaf area were captured by coniferous tree species than by broad‐leaved tree species in a particular order—i.e., Pinus tabuliformis > Pinus bungeana > Salix matsudana > Acer truncatum > Ginkgo biloba > Populus tomentosa; (2 Significant seasonal variation in particulate‐capturing capacities were determined. During the observation period, the broad‐leaved tree species capturing TSP and coarse particulate matter (PM10 clearly exhibited a ∩‐shape pattern— that is, increasing initially and later on decreasing; meanwhile, the ∩‐shape pattern was not clearly shown in P. tabuliformis and P. bungeana. However, no obvious patterns in the absorption of fine particulate matter (PM2.5 were found in the tested tree species; (3 The leaf surface topography, as observed by AFM and scanning electron microscopy, revealed that the broad‐leaved tree exhibits a good correlation between micro‐roughness of leaf surfaces and density of particles settling on leaf surfaces over time. However, the main factors affecting the adsorptive capacities of the leaves in coniferous trees are the number of stomata as well as the amount of epicuticular wax and the properties of the cuticle in different seasons.

  17. Do leaf surface characteristics affect Agrobacterium infection in tea ...

    Indian Academy of Sciences (India)

    Unknown

    bouring hpt and gusint) were grown in liquid yeast manni- tol broth (YMB) medium ..... C58C1 towards vir inducing phenolic compounds and solu- ble factors from ... fluence of UV-B radiation on the physicochemical nature of tobacco (Nicotiana ... 1995 Leaf epicuticular waxes of the Eceriferum mutants in. Arabidopsis; Plant ...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-04-15

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

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

    DEFF Research Database (Denmark)

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

    2014-01-01

    to this, we demonstrated that the UV radiation-induced CH4 emission is independent of leaf area index above unity. Further, we observed that the presence of O2 in the atmosphere was necessary for achieving the highest rates of CH4 emission. Methane formation from leaf surface wax is supposedly a two...... investigated the potential of the leaf surface wax itself as a source of UV radiationinduced leaf aerobic CH4 formation. Isolated leaf surface wax emitted CH4 at substantial rates in response to UV radiation. This discovery has implications for how the phenomenon should be scaled to global levels. In relation...

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

    Science.gov (United States)

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

    2015-05-05

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-25

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

  2. LEAF MICROMOPHOMETRY OF PALICOUREA RIGIDA KUNTH. (RUBIACEAE FROM BRAZILIAN CERRADO AND CAMPO RUPESTRE ENVIRONMENTS

    Directory of Open Access Journals (Sweden)

    Manuel Losada Gavilanes

    2016-06-01

    Full Text Available The objective of this work was to evaluate qualitative and quantitative leaf anatomical traits of Palicourea rigida Kunth. (Rubiaceae species occurring in the Brazilian Cerrado and Campo Rupestre ecosystems. Anatomical analysis was performed in fresh or fixed leaves processed with usual plant microtechnique. Leaves showed uniseriate epidermis in petiole and leaf blade which contains uniseriate nonglandular tricomes (tector type occurring only over the vascular bundles. Likewise, paracytic stomata were found only in abaxial side of the leaf surface. The mesophyll contains uniseriate palisade parenchyma and multiseriate spongy parenchyma (nine layers which showed cells with different morphology and size. Crystal idoblasts of different types were observed in both the petiole and leaf blade. Collateral vascular bundles were found both in the petiole and leaf blade. Leaf venation type was pinnate, campylodromous or brochydodromous. The micromorphometric analysis showed significant differences from plants of different environments for all leaf characteristics and Cerrado plants showed higher means for all evaluated traits. Therefore, the influence of environments may had modulated morphological responses in P. rigida, since no difference was found in the type or distribution of leaf tissues in Cerrado or Campo Rupestre.

  3. Surface contamination effects on leaf chemical composition in the Atlantic Forest

    International Nuclear Information System (INIS)

    Ferrari, A.A.; Franca, E.J.; Fernandes, E.A.N.; Bacchi, M.A.

    2006-01-01

    The exogenous material that adheres to the leaf surface affects the elemental composition of the plant itself, thereby constituting one of the major error sources in plant analysis. The present work investigated the surface contamination of leaves from the Atlantic Forest. Instrumental neutron activation analysis (INAA) was applied to assess the efficiency of leaf EDTA-washing. Chemical element concentrations were corrected using Sc (soil tracer) since resuspended soil is the main source of contamination in leaves. As a result, EDTA-washing should be used mainly for the evaluation of terrigenous elements, while the Sc-corrected concentrations are considered satisfactory for the other elements. (author)

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

    NARCIS (Netherlands)

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

    2000-01-01

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

  5. Behavioral Plasticity in Probing by Diaphorina citri (Hemiptera, Liviidae): Ingestion from Phloem Versus Xylem is Influenced by Leaf Age and Surface.

    Science.gov (United States)

    Ebert, Timothy A; Backus, Elaine A; Shugart, Holly J; Rogers, Michael E

    2018-01-01

    Diaphorina citri is a major pest of citrus because it transmits Candidatus Liberibacter asiaticus, a phloem-limited bacterium that putatively causes Huanglongbing (HLB). The disease moves slowly through a tree, and the vector facilitates further within-tree movement via transmission of the pathogen. However, this only happens when D. citri stylets contact the phloem, to inoculate bacteria during phloem salivation and acquire bacteria during phloem sap ingestion. Behavioral changes in D. citri associated with different plant parts would affect how long it takes to reach phloem and how long the psyllids stays in phloem to ingest, thereby influencing the risk of disease spread. D. citri feeding was recorded on the abaxial and adaxial surfaces of mature and immature citrus leaves. Adults in the field can be found on these surfaces at all times of year. On abaxial surface of immature leaves, phloem salivation would occur after 11 h on average, but rarely as soon as 0.56 h. The corresponding values on mature leaves were 16 and 2.7. In general, psyllids spent more time ingesting phloem sap on immature leaves than on mature leaves. Psyllids on abaxial surfaces spent more time ingesting from phloem, though the strength of this effect was less than for immature versus mature leaves. In contrast, xylem ingestion increased on mature leaves compared with young. The biological differences that could produce this outcome are discussed. The results discussed herein are of relevance to further studies on the efficacy of an insecticide to act quickly enough to prevent pathogen transmission.

  6. Eelgrass Leaf Surface Microbiomes Are Locally Variable and Highly Correlated with Epibiotic Eukaryotes

    Directory of Open Access Journals (Sweden)

    Mia M. Bengtsson

    2017-07-01

    Full Text Available Eelgrass (Zostera marina is a marine foundation species essential for coastal ecosystem services around the northern hemisphere. Like all macroscopic organisms, it possesses a microbiome (here defined as an associated prokaryotic community which may play critical roles in modulating the interaction of eelgrass with its environment. For example, its leaf surface microbiome could inhibit or attract eukaryotic epibionts which may overgrow the eelgrass leading to reduced primary productivity and subsequent eelgrass meadow decline. We used amplicon sequencing of the 16S and 18S rRNA genes of prokaryotes and eukaryotes to assess the leaf surface microbiome (prokaryotes as well as eukaryotic epibionts in- and outside lagoons on the German Baltic Sea coast. Prokaryote microbiomes varied substantially both between sites inside lagoons and between open coastal and lagoon sites. Water depth, leaf area and biofilm chlorophyll a concentration explained a large amount of variation in both prokaryotic and eukaryotic community composition. The prokaryotic microbiome and eukaryotic epibiont communities were highly correlated, and network analysis revealed disproportionate co-occurrence between a limited number of eukaryotic taxa and several bacterial taxa. This suggests that eelgrass leaf surfaces are home to a mosaic of microbiomes of several epibiotic eukaryotes, in addition to the microbiome of the eelgrass itself. Our findings thereby underline that eukaryotic diversity should be taken into account in order to explain prokaryotic microbiome assembly and dynamics in aquatic environments.

  7. A simulation model of distributions of radiational flux at leaf surfaces in crowns of fruit trees

    International Nuclear Information System (INIS)

    Yamamoto, T.

    1988-01-01

    A computer-model was constructed for estimating distributions with time of radiational fluxes at leaf surfaces throughout fruit tree canopies in which leaves did not distribute uniformely in three dimensional space. Several assumptions were set up to construct the model for approximation of using solid geometry. For irregular distribution of leaf area in three dimensional space data were used in the simulation as number of leaves per internal cubic bloc of a cubic grid (n-divided per side). Several main parameters used were peculiar to fruit species which contain parameters (λ, ν) of Beta function to calculate both probability density function of leaf area distribution with respect to inclination angle and leaf extinction coefficient for parallel beam by leaves parameters (A, R i ) to calculate stem extinction coefficient for parallel beam, and parameters (D i ) to calculate leaf extinction coefficient of downward transmission and downward reflection. With these data and parameters solid geometry and Lambert-Beer's law constituted this model

  8. Microbial rhodopsins on leaf surfaces of terrestrial plants

    OpenAIRE

    Atamna-Ismaeel, Nof; Finkel, Omri M.; Glaser, Fabian; Sharon, Itai; Schneider, Ron; Post, Anton F.; Spudich, John L.; von Mering, Christian; Vorholt, Julia A.; Iluz, David; Béjà, Oded; Belkin, Shimshon

    2011-01-01

    The above-ground surfaces of terrestrial plants, the phyllosphere, comprise the main interface between the terrestrial biosphere and solar radiation. It is estimated to host up to 1026 microbial cells that may intercept part of the photon flux impinging on the leaves. Based on 454-pyrosequencing-generated metagenome data, we report on the existence of diverse microbial rhodopsins in five distinct phyllospheres from tamarisk (Tamarix nilotica), soybean (Glycine max), Arabidopsis (Arabidopsis t...

  9. New photodegradation products of chlorpyrifos and their detection on glass, soil, and leaf surfaces

    International Nuclear Information System (INIS)

    Walia, S.; Dureja, P.; Mukerjee, S.K.

    1988-01-01

    The organophosphate insecticide chlorpyrifos was irradiated under different photochemical conditions and the products characterized by gas chromatography, mass spectrometry, and NMR spectroscopy. Irradiation of chlorpyrifos in hexane yielded dechlorinated photoproducts and cleavage products. In methanol, besides these products, chlorpyrifos gave oxons. Several new photoproducts, the formation of which apparently occurs by the displacement of 5-chloro by a methoxy substituent in the pyridyl moiety. The possibility of formation of such products on glass, soil, and leaf surfaces under the influence of UV and solar simulated light have also been explored and many new products presumably formed due to simultaneous photo-dechlorination, oxidation and hydrolytic processes were detected. Photodegradation of chlorpyrifos was rapid on a soil surface but comparatively slow on glass and leaf surfaces

  10. The heterogeneity and spatial patterning of structure and physiology across the leaf surface in giant leaves of Alocasia macrorrhiza.

    Directory of Open Access Journals (Sweden)

    Shuai Li

    Full Text Available Leaf physiology determines the carbon acquisition of the whole plant, but there can be considerable variation in physiology and carbon acquisition within individual leaves. Alocasia macrorrhiza (L. Schott is an herbaceous species that can develop very large leaves of up to 1 m in length. However, little is known about the hydraulic and photosynthetic design of such giant leaves. Based on previous studies of smaller leaves, and on the greater surface area for trait variation in large leaves, we hypothesized that A. macrorrhiza leaves would exhibit significant heterogeneity in structure and function. We found evidence of reduced hydraulic supply and demand in the outer leaf regions; leaf mass per area, chlorophyll concentration, and guard cell length decreased, as did stomatal conductance, net photosynthetic rate and quantum efficiency of photosystem II. This heterogeneity in physiology was opposite to that expected from a thinner boundary layer at the leaf edge, which would have led to greater rates of gas exchange. Leaf temperature was 8.8°C higher in the outer than in the central region in the afternoon, consistent with reduced stomatal conductance and transpiration caused by a hydraulic limitation to the outer lamina. The reduced stomatal conductance in the outer regions would explain the observed homogeneous distribution of leaf water potential across the leaf surface. These findings indicate substantial heterogeneity in gas exchange across the leaf surface in large leaves, greater than that reported for smaller-leafed species, though the observed structural differences across the lamina were within the range reported for smaller-leafed species. Future work will determine whether the challenge of transporting water to the outer regions can limit leaf size for plants experiencing drought, and whether the heterogeneity of function across the leaf surface represents a particular disadvantage for large simple leaves that might explain their

  11. Phylogenetic ecology of leaf surface traits in the milkweeds (Asclepias spp.): chemistry, ecophysiology, and insect behavior.

    Science.gov (United States)

    Agrawal, Anurag A; Fishbein, Mark; Jetter, Reinhard; Salminen, Juha-Pekka; Goldstein, Jessica B; Freitag, Amy E; Sparks, Jed P

    2009-08-01

    The leaf surface is the contact point between plants and the environment and plays a crucial role in mediating biotic and abiotic interactions. Here, we took a phylogenetic approach to investigate the function, trade-offs, and evolution of leaf surface traits in the milkweeds (Asclepias). Across 47 species, we found trichome densities of up to 3000 trichomes cm(-2) and epicuticular wax crystals (glaucousness) on 10 species. Glaucous species had a characteristic wax composition dominated by very-long-chain aldehydes. The ancestor of the milkweeds was probably a glaucous species, from which there have been several independent origins of glabrous and pubescent types. Trichomes and wax crystals showed negatively correlated evolution, with both surface types showing an affinity for arid habitats. Pubescent and glaucous milkweeds had a higher maximum photosynthetic rate and lower stomatal density than glabrous species. Pubescent and glaucous leaf surfaces impeded settling behavior of monarch caterpillars and aphids compared with glabrous species, although surface types did not show consistent differentiation in secondary chemistry. We hypothesize that pubescence and glaucousness have evolved as alternative mechanisms with similar functions. The glaucous type, however, appears to be ancestral, lost repeatedly, and never regained; we propose that trichomes are a more evolutionarily titratable strategy.

  12. Anatomy of leaf and stem of Erythrina velutina

    Directory of Open Access Journals (Sweden)

    Márcia M. B. da Silva

    2013-04-01

    Full Text Available Erythrina velutina Willd., Fabaceae, known as "mulungu", is a tree of tropical regions, as northeastern Brazil. Its bark is used in folk medicine as tranquilizer, sedative and insomnia. This study aimed to characterize the stem and leaf anatomy and to provide subsidies to quality control of the plant drug due to its wide use in folk medicine as well as its differentiation from other species with the same popular name. Samples were collected at Cuité, in Paraíba State, Brazil, fixed in FAA50, semipermanent slides were made, following usual procedures in plant anatomy. The stem shows a cylindrical contour, covered by a uniseriate epidermis covered by a thickened cuticle. It shows claviform glandular and branched trichomes with uniseriate stalk. Secretory cavities are into the phloem. The leaf epidermis has branched and glandular trichomes and anisocytic and paracytic stomata, on both sides, with predominance of branched trichomes and stomata on abaxial surface. Secretory cavities in stem and leaf, types of trichomes and stomata, its location and distribution constitute diagnostic characters for this specie. The structural characterization of the stem and leaf allows its distinction from other ones of this genus, ensuring safety for commercial pharmacological uses, allowing certification of the authenticity of raw material.

  13. Anatomy of leaf and stem of Erythrina velutina

    Directory of Open Access Journals (Sweden)

    Márcia M. B. da Silva

    2013-02-01

    Full Text Available Erythrina velutina Willd., Fabaceae, known as "mulungu", is a tree of tropical regions, as northeastern Brazil. Its bark is used in folk medicine as tranquilizer, sedative and insomnia. This study aimed to characterize the stem and leaf anatomy and to provide subsidies to quality control of the plant drug due to its wide use in folk medicine as well as its differentiation from other species with the same popular name. Samples were collected at Cuité, in Paraíba State, Brazil, fixed in FAA50, semipermanent slides were made, following usual procedures in plant anatomy. The stem shows a cylindrical contour, covered by a uniseriate epidermis covered by a thickened cuticle. It shows claviform glandular and branched trichomes with uniseriate stalk. Secretory cavities are into the phloem. The leaf epidermis has branched and glandular trichomes and anisocytic and paracytic stomata, on both sides, with predominance of branched trichomes and stomata on abaxial surface. Secretory cavities in stem and leaf, types of trichomes and stomata, its location and distribution constitute diagnostic characters for this specie. The structural characterization of the stem and leaf allows its distinction from other ones of this genus, ensuring safety for commercial pharmacological uses, allowing certification of the authenticity of raw material.

  14. Penetration of UV-A, UV-B and blue light through the leaf trichome layers of two xeromorphic plants, olive and oak, measured by optical fibre microprobes

    International Nuclear Information System (INIS)

    Karabourniotis, G.; Bornman, J.F.

    1999-01-01

    Quartz fibre-optic microprobes were used to monitor the light microenvironment beneath trichome layers of the xeromorphic leaves of two Mediterranean evergreen sclerophylls, Olea europaea and Quercus ilex. Young developing leaves of both plants were densely pubescent on both surfaces of the lamina, whereas the mature leaves were pubescent only on the abaxial side. Trichome layers of young as well as of mature leaves of both plants attenuated almost all incident ultraviolet (UV)-B (310 nm) and UV-A (360 nm) radiation and a considerable portion of blue light (430 nm). Abaxial trichome layers of young leaves were more effective in screening out the incident radiation compared to the adaxial ones of the same leaves and also compared to the abaxial layer of the mature leaves. The abaxial epidermis of dehaired mature leaves of O. europaea was ineffective in absorbing most of the incident UV-B and UV-A radiation. UV and visible spectra beneath trichome layers of O. europaea in mature leaves confirmed that the light microenvironment on the epidermis was deprived in the UV-B, UV-A and partly in the blue spectral regions. It is proposed that the occurrence of a dense trichome layer, especially in young leaves, may play a protective role against not only UV-B radiation damage, but also against high visible irradiance. This function is performed irrespective of the differing anatomy of individual hairs of both plants. The protection provided by the trichomes could afford advantages under stress conditions, especially during leaf development. (author)

  15. Management of Surface Drying Temperature to Increase Antioxidant Capacity of Thyme Leaf Extracts (Thymus vulgaris L.)

    OpenAIRE

    RODRIGUEZ CORTINA, JADER; Melo, E.C.; Mulet Pons, Antonio; Bon Corbín, José

    2014-01-01

    [EN] Thyme leaves are an important source of essential oils with antioxidant activity; these compounds are located in trichomes on the leaf surface. The drying conditions affect not only the drying time but also the antioxidant activity. In the literature, a drying temperature of 70 ºC appears to be the best for drying thyme leaves according to their antioxidant capacity. Considering drying periods at different temperature also could be quality beneficial. From these considerations, the goal ...

  16. Responses of herbaceous plants to urban air pollution: Effects on growth, phenology and leaf surface characteristics

    International Nuclear Information System (INIS)

    Honour, Sarah L.; Bell, J. Nigel B.; Ashenden, Trevor W.; Cape, J. Neil; Power, Sally A.

    2009-01-01

    Vehicle exhaust emissions are a dominant feature of urban environments and are widely believed to have detrimental effects on plants. The effects of diesel exhaust emissions on 12 herbaceous species were studied with respect to growth, flower development, leaf senescence and leaf surface wax characteristics. A diesel generator was used to produce concentrations of nitrogen oxides (NO x ) representative of urban conditions, in solardome chambers. Annual mean NO x concentrations ranged from 77 nl l -l to 98 nl l -1 , with NO:NO 2 ratios of 1.4-2.2, providing a good experimental simulation of polluted roadside environments. Pollutant exposure resulted in species-specific changes in growth and phenology, with a consistent trend for accelerated senescence and delayed flowering. Leaf surface characteristics were also affected; contact angle measurements indicated changes in surface wax structure following pollutant exposure. The study demonstrated clearly the potential for realistic levels of vehicle exhaust pollution to have direct adverse effects on urban vegetation. - Fumigation experiments demonstrate adverse effects of exhaust emissions on urban vegetation

  17. Effect of Leaf Surface Chemical Properties on Efficacy of Sanitizer for Rotavirus Inactivation

    Science.gov (United States)

    Fuzawa, Miyu; Ku, Kang-Mo; Palma-Salgado, Sindy Paola; Nagasaka, Kenya; Feng, Hao; Juvik, John A.; Sano, Daisuke; Shisler, Joanna L.

    2016-01-01

    ABSTRACT The use of sanitizers is essential for produce safety. However, little is known about how sanitizer efficacy varies with respect to the chemical surface properties of produce. To answer this question, the disinfection efficacies of an oxidant-based sanitizer and a new surfactant-based sanitizer for porcine rotavirus (PRV) strain OSU were examined. PRV was attached to the leaf surfaces of two kale cultivars with high epicuticular wax contents and one cultivar of endive with a low epicuticular wax content and then treated with each sanitizer. The efficacy of the oxidant-based sanitizer correlated with leaf wax content as evidenced by the 1-log10 PRV disinfection on endive surfaces (low wax content) and 3-log10 disinfection of the cultivars with higher wax contents. In contrast, the surfactant-based sanitizer showed similar PRV disinfection efficacies (up to 3 log10) that were independent of leaf wax content. A statistical difference was observed with the disinfection efficacies of the oxidant-based sanitizer for suspended and attached PRV, while the surfactant-based sanitizer showed similar PRV disinfection efficacies. Significant reductions in the entry and replication of PRV were observed after treatment with either disinfectant. Moreover, the oxidant-based-sanitizer-treated PRV showed sialic acid-specific binding to the host cells, whereas the surfactant-based sanitizer increased the nonspecific binding of PRV to the host cells. These findings suggest that the surface properties of fresh produce may affect the efficacy of virus disinfection, implying that food sanitizers should be carefully selected for the different surface characteristics of fresh produce. IMPORTANCE Food sanitizer efficacies are affected by the surface properties of vegetables. This study evaluated the disinfection efficacies of two food sanitizers, an oxidant-based sanitizer and a surfactant-based sanitizer, on porcine rotavirus strain OSU adhering to the leaf epicuticular surfaces of

  18. Leaf, stem bark and fruit anatomy of zanthoxylum armatum dc. (rutaceae)

    International Nuclear Information System (INIS)

    Barkatullah, A.; Ibrar, M.; Jelani, G.; Ahmad, I.

    2014-01-01

    Zanthoxylum armatum DC. (Rutaceae) is an important medicinal plant. The present study deals with anatomical exploration of the leaf, stem bark and fruit of this plant. Leaf of Z. armatum is bifacial, compound and punctate with glabrous surfaces having a single layer of epidermis and palisade mesophyll. The leaf has a Palisade ratio ranged from 6.00 to 9.00 (8.2 +- 0.32). Vein islets and vein termination number were 14-21 (16.8 +- 0.64) and 17-21 (19.1 +- 0.43) per mm2 respectively. The vein-islets were quite distinct with squaresh, elongated, polygonal or irregular in shape bounding many forked and unforked vascular branches. Adaxial surface of Z. armatum leaf midrib was planoconvex while the abaxial surface was semicircular in appearance. The diagnostic feature of the leaf was the complete absence of any kind of trichomes or any other appendages. The leaf showed prominent oil cavities. Nine types of stomata with different frequencies and other dimensions were observed. Brachparatetracytic stomata was the most frequent stoma (80%) followed by actinostephanocytic (40%) and then straucytic and brachyparacytic (30%) each. Hemiparacytic and stomatal cluster were the rarely occurring stomata (10% each) present on the lower epidermis of the leaf. Stomatal cluster, which is considered to be a special leaf epidermal feature and reported only in few genera of vascular plants, was also recorded in this plant. Bark and fruit anatomy of Z. armatum showed different tissue arrangement. The seed was non endospermic and contains an elongated embryo. The present study will be helpful in the phylogeny and taxonomic description of this important medicinal plant. (author)

  19. Nanocrystalline nickel films with lotus leaf texture for superhydrophobic and low friction surfaces

    Science.gov (United States)

    Shafiei, Mehdi; Alpas, Ahmet T.

    2009-11-01

    Nanostructured Ni films with high hardness, high hydrophobicity and low coefficient of friction (COF) were fabricated. The surface texture of lotus leaf was replicated using a cellulose acetate film, on which a nanocrystalline (NC) Ni coating with a grain size of 30 ± 4 nm was electrodeposited to obtain a self-sustaining film with a hardness of 4.42 GPa. The surface texture of the NC Ni obtained in this way featured a high density (4 × 10 3 mm -2) of conical protuberances with an average height of 10.0 ± 2.0 μm and a tip radius of 2.5 ± 0.5 μm. This structure increased the water repellency and reduced the COF, compared to smooth NC Ni surfaces. The application of a short-duration (120 s) electrodeposition process that deposited "Ni crowns" with a larger radius of 6.0 ± 0.5 μm on the protuberances, followed by a perfluoropolyether (PFPE) solution treatment succeeded in producing a surface texture consisting of nanotextured protuberances that resulted in a very high water contact angle of 156°, comparable to that of the superhydrophobic lotus leaf. Additionally, the microscale protuberances eliminated the initial high COF peaks observed when smooth NC Ni films were tested, and the PFPE treatment resulted in a 60% reduction in the steady-state COFs.

  20. Fluid drag reduction and efficient self-cleaning with rice leaf and butterfly wing bioinspired surfaces

    Science.gov (United States)

    Bixler, Gregory D.; Bhushan, Bharat

    2013-08-01

    Researchers are continually inspired by living nature to solve complex challenges. For example, unique surface characteristics of rice leaves and butterfly wings combine the shark skin (anisotropic flow leading to low drag) and lotus leaf (superhydrophobic and self-cleaning) effects, producing the so-called rice and butterfly wing effect. In this paper, we present an overview of rice leaf and butterfly wing fluid drag and self-cleaning studies. In addition, we examine two other promising aquatic surfaces in nature known for such properties, including fish scales and shark skin. Morphology, drag, self-cleaning, contact angle, and contact angle hysteresis data are presented to understand the role of wettability, viscosity, and velocity. Liquid repellent coatings are utilized to recreate or combine various effects. Discussion is provided along with conceptual models describing the role of surface structures related to low drag, self-cleaning, and antifouling properties. Modeling provides design guidance when developing novel low drag and self-cleaning surfaces for applications in the medical, marine, and industrial fields.

  1. Leaf wettability as a measure of air pollution effects

    International Nuclear Information System (INIS)

    Jagels, R.

    1994-01-01

    Droplet contact angle (DCA) is a technique that can be used to measure wettability and, in turn, provide an assessment of the physical and chemical characteristics of a surface. As adapted to plant bioligy, DCA measurements have been useful in characterizing changes in the type or condition of leaf epicuticular waxes. Environmental as well as temporal factors can modify the biophysical features of epicuticular wax surfaces and thereby affect DCA measurements. An understanding of the role of these non-pollutant factors is necessary before pollution damage can be accurately assessed. Controlled chamber experiments and field pollutant gradient studies have shown that DCA is generally reduced when plants are exposed to air pollutants such as ozone, So 2 , and acidic fog. In some cases, environmental influences, such as temperature, have been separated from the pollutant effect. However, mixtures of anthropogenic pollutants or anthropogenic and natural compounds (sea salts, dust particles) which are often present in field studies can confound the interpretation of DCA measurements. A few studies that attempt to separate these factors have been conducted, but more are needed before the potential for using DCA measurements in long-term bioindicator studies can be fully realized. Some studies have demonstrated that pollutants do not necessarily affect leaf surfaces in a uniform pattern, but rather are specific for certain structures such as stomates or trichomes; deposition levels can also be different on ad-and abaxial surfaces. The degree to which these inhomogeneities of action can affect DCA measurements needs further study. (orig.)

  2. Relevance of leaf surface contamination for assessing chemical composition of bromeliads in a restinga forest

    Energy Technology Data Exchange (ETDEWEB)

    Elias, C; Fernandes, E A.N.; Franca, E J; Bacchi, M A; Tagliaferro, F S [Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo, Piracicaba, SP (Brazil)

    2008-11-15

    Resuspended soil and other airborne particles adhered to the leaf surface affect the chemical composition of the plant. A well-defined cleaning procedure is necessary to avoid this problem, providing a correct assessment of the inherent chemical composition of bromeliads. To evaluate the influence of a washing procedure, INAA was applied for determining chemical elements in the leaves of bromeliads from Vriesea carinata species, both non-washed and washed with Alconox, EDTA and bi-distilled water. Br, Ce, Hg, La, Sc, Se, Sm and Th showed higher mass fractions in nonwashed leaves. The washing procedure removed the exogenous material without leaching chemical elements from inside the tissues. (author)

  3. Leaf surface wetness and evaporation studies with a β-ray gauge

    International Nuclear Information System (INIS)

    Barthakur, N.N.

    1984-01-01

    Surface wetness duration was measured by a β-ray gauge as a function of wind velocity in the laboratory. The instrument was field-tested as a dewmeter over a wax bean canopy. Diurnal variations of the net count rate through a turgid tobacco leaf measured by a β-ray gauge system corresponded with the stomatal movement. The approximate exponential relationship of the transmission of β-particles with absorber thickness was found acceptable to study rates of evaporation from free water and through pores. The cumulative rate of evaporation of free water varied linearly with time. Three distinct stages of evaporation rates were observed through a porous medium. (author)

  4. Relevance of leaf surface contamination for assessing chemical composition of bromeliads in a restinga forest

    International Nuclear Information System (INIS)

    Elias, C.; Fernandes, E.A.N.; Franca, E.J.; Bacchi, M.A.; Tagliaferro, F.S.

    2008-01-01

    Resuspended soil and other airborne particles adhered to the leaf surface affect the chemical composition of the plant. A well-defined cleaning procedure is necessary to avoid this problem, providing a correct assessment of the inherent chemical composition of bromeliads. To evaluate the influence of a washing procedure, INAA was applied for determining chemical elements in the leaves of bromeliads from Vriesea carinata species, both non-washed and washed with Alconox, EDTA and bi-distilled water. Br, Ce, Hg, La, Sc, Se, Sm and Th showed higher mass fractions in nonwashed leaves. The washing procedure removed the exogenous material without leaching chemical elements from inside the tissues. (author)

  5. Ultrasonographic anatomy of the dorsal and abaxial aspects of the equine fetlock.

    Science.gov (United States)

    Denoix, J M; Jacot, S; Bousseau, B; Perrot, P

    1996-01-01

    This paper describes normal ultrasound images of the soft tissues of the dorsal and abaxial aspects of the equine fetlock. The palmar aspect of the fetlock is not discussed because it is related to the suspensory apparatus and flexor tendon anatomy which has been previously described. Ultrasound scanning was performed with 7.5 MHz linear or 10 MHz sector probes and recorded on 7.5 cm U-matic videocassettes allowing further retrospective data analysis, computer manipulation and good image reproducibility. Sagittal, parasagittal, frontal and transverse ultrasound scans of 13 lameness free mature horses were compared to anatomically dissected leg specimens, anatomical sections and Magnetic Resonance Imaging scans of isolated limbs. The results are focused on the comparison between anatomical sections and ultrasonograms performed on the legs of nonlame horses. Ultrasonography was demonstrated to be a very accurate imaging procedure for soft tissue structures at the dorsal and abaxial aspects of the equine fetlock. Under clinical conditions, a thorough knowledge of normal ultrasonographic anatomy is critical for an accurate diagnosis of fetlock soft tissue injury.

  6. Evolution at the tips: Asclepias phylogenomics and new perspectives on leaf surfaces.

    Science.gov (United States)

    Fishbein, Mark; Straub, Shannon C K; Boutte, Julien; Hansen, Kimberly; Cronn, Richard C; Liston, Aaron

    2018-03-01

    Leaf surface traits, such as trichome density and wax production, mediate important ecological processes such as anti-herbivory defense and water-use efficiency. We present a phylogenetic analysis of Asclepias plastomes as a framework for analyzing the evolution of trichome density and presence of epicuticular waxes. We produced a maximum-likelihood phylogeny using plastomes of 103 species of Asclepias. We reconstructed ancestral states and used model comparisons in a likelihood framework to analyze character evolution across Asclepias. We resolved the backbone of Asclepias, placing the Sonoran Desert clade and Incarnatae clade as successive sisters to the remaining species. We present novel findings about leaf surface evolution of Asclepias-the ancestor is reconstructed as waxless and sparsely hairy, a macroevolutionary optimal trichome density is supported, and the rate of evolution of trichome density has accelerated. Increased sampling and selection of best-fitting models of evolution provide more resolved and robust estimates of phylogeny and character evolution than obtained in previous studies. Evolutionary inferences are more sensitive to character coding than model selection. © 2018 The Authors. American Journal of Botany is published by Wiley Periodicals, Inc. on behalf of the Botanical Society of America.

  7. Far-red enrichment and photosynthetically active radiation level influence leaf senescence in field-grown sunflower

    International Nuclear Information System (INIS)

    Rousseaux, M.C.; Hall, A.J.; Sánchez, R.A.

    1996-01-01

    Basal leaves frequently senesce before anthesis in high population density crops. This paper evaluates the hypothesis that quantitative and qualitative changes in the light environment associated with a high leaf area index (LAI) trigger leaf senescence in sunflower (Helianthus annuus L.) canopies. Mean leaf duration (LD, time from achievement of maximum leaf area) of leaf 8 was significantly (P < 0.05) reduced from 51 to 19 days as crop population density was increased from 0.47 to 4.76 plants m−2. High compared to low plant population density was associated with earlier reduction in the photosynthetically active radiation (PAR) and red/far-red ratio (R/FR) reaching the target leaf. However the changes in R/FR preceded those in PAR. When the light environment of individual leaves of isolated plants growing under field conditions was manipulated using filters and FR-reflecting mirrors, LD was positively and linearly related with the mean daily PAR (MDR) received in the FR- (no FR enrichment) treatments. FR enrichment of light reaching the abaxial surface of the leaf significantly (P < 0.05) reduced LD by 9 days at intermediate PAR levels with respect to FR-controls, but did not affect LD at the maximum PAR used in these experiments. However, when light reaching both leaf surfaces was enriched with FR, LD (for leaves receiving maximum PAR) was 13 days shorter than that of the FR- control. These results show that basal leaf senescence in sunflower is enhanced both by a decrease in PAR and by a decrease in R/FR. (author)

  8. A Robust Inversion Algorithm for Surface Leaf and Soil Temperatures Using the Vegetation Clumping Index

    Directory of Open Access Journals (Sweden)

    Zunjian Bian

    2017-07-01

    Full Text Available The inversion of land surface component temperatures is an essential source of information for mapping heat fluxes and the angular normalization of thermal infrared (TIR observations. Leaf and soil temperatures can be retrieved using multiple-view-angle TIR observations. In a satellite-scale pixel, the clumping effect of vegetation is usually present, but it is not completely considered during the inversion process. Therefore, we introduced a simple inversion procedure that uses gap frequency with a clumping index (GCI for leaf and soil temperatures over both crop and forest canopies. Simulated datasets corresponding to turbid vegetation, regularly planted crops and randomly distributed forest were generated using a radiosity model and were used to test the proposed inversion algorithm. The results indicated that the GCI algorithm performed well for both crop and forest canopies, with root mean squared errors of less than 1.0 °C against simulated values. The proposed inversion algorithm was also validated using measured datasets over orchard, maize and wheat canopies. Similar results were achieved, demonstrating that using the clumping index can improve inversion results. In all evaluations, we recommend using the GCI algorithm as a foundation for future satellite-based applications due to its straightforward form and robust performance for both crop and forest canopies using the vegetation clumping index.

  9. Effect of Extraction Process and Surface Treatment on the mechanical properties in Pineapple Leaf Fibre

    Directory of Open Access Journals (Sweden)

    Ariffin Azrie

    2017-01-01

    Full Text Available Pineapple Leaf Fibre (PALF is a one of the natural fibre that has high potential in the industry. Natural fibres have become the main alternative source in the modern world industry. The objective of this study is to observe the effect chemical treatment using Sodium Hydroxide (NaOH solution on the physical and mechanical properties of pineapple leaf fibre. Different concentration of NaOH solution (2%, 4%, 6%, 8% and different treatment time (1 hour, 3 hour and 5 hour are used for the experiment. The tensile test was conducted to obtain the mechanical properties such as tensile strength, Yong modulus, (E and elongation at break. From the results obtained, NaOH concentration of 6% and five-hour treatment time that was used for treatment showed the higher physical and mechanical properties values. Furthermore, morphology analysis also shows the surface of the fibre at 6% NaOH after five-hour of treatment was in the better condition with good bonding arrangement of the fibre.

  10. Response of sugar beet plants to ultraviolet-B (280-320 nm) radiation and Cercospora leaf spot disease

    International Nuclear Information System (INIS)

    Panagopoulos, I.; Bornman, J.F.; Björn, L.O.

    1992-01-01

    Sugar beet (Beta vulgaris L.) plants injected with Cercospora beticola Sacc. as well as non-infected plants were grown under visible light with or without ultraviolet-B (UV-B, 280-320 nm) radiation for 40 days. An interaction between UV-B radiation and Cercospora leaf spot disease was observed, resulting in a large reduction in leaf chlorophyll content, dry weight of leaf laminae, petioles and storage roots. Lipid peroxidation in leaves also increased the most under the combined treatments. This was also true for ultraweak luminescence from both adaxial and abaxial leaf surfaces. However, no correlation between lipid peroxidation and ultraweak luminescence was observed. Ultraviolet-B radiation given alone appeared to have either a stimulating effect, giving an increase in dry weight of laminac and reducing lipid peroxidation, or no effect. This lack of effect was seen in the absence of change in dry weight of storage roots and chlorophyll content relative to controls. The study demonstrated a harmful interaction between UV-B radiation and Cercospora leaf spot disease on sugar beet

  11. Sesquiterpene Lactones of Amphoricarpos autariatus ssp. autariatus from Montenegro - Antifungal Leaf - Surface Constituents

    Directory of Open Access Journals (Sweden)

    Milka Jadranin

    2013-05-01

    Full Text Available The composition of leaf cuticular neutral lipids of Amphoricarpos autariatus ssp. autariatus collected at canyon of river Tara (North Montenegro was investigated by GC/MS (nonpolar fraction, LC-ESI TOF MS and 1H NMR spectroscopy (more polar fraction. The nonpolar fraction (ca. 15% of the whole surface extract contained C 27 - 33 n-alkanes, those with odd-number of carbons predominating. The LC-ESI MS and 1H NMR of the more polar fraction revealed 13 sesquiterpene lactones, constituting ca. 97.5% of the lactone mixture, identified as the known guaianolides, so-called amphoricarpolides, found previously in the aerial parts of the genus. The lactone fraction exhibited considerable in vitro effect against eight fungi, i.e. Aspergillus ochraceus , A. niger, A. versicolor , Penicillium funiculosum, P. ochrochloron, Trichoderma viride, Fusarium verticillioides and Fulvia fulvum.

  12. 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

  13. In Situ Nondestructive Analysis of Kalanchoe pinnata Leaf Surface Structure by Polarization-Modulation Infrared Reflection-Absorption Spectroscopy.

    Science.gov (United States)

    Hama, Tetsuya; Kouchi, Akira; Watanabe, Naoki; Enami, Shinichi; Shimoaka, Takafumi; Hasegawa, Takeshi

    2017-12-14

    The outermost surface of the leaves of land plants is covered with a lipid membrane called the cuticle that protects against various stress factors. Probing the molecular-level structure of the intact cuticle is highly desirable for understanding its multifunctional properties. We report the in situ characterization of the surface structure of Kalanchoe pinnata leaves using polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS). Without sample pretreatment, PM-IRRAS measures the IR spectra of the leaf cuticle of a potted K. pinnata plant. The peak position of the CH 2 -related modes shows that the cuticular waxes on the leaf surface are mainly crystalline, and the alkyl chains are highly packed in an all-trans zigzag conformation. The surface selection rule of PM-IRRAS revealed the average orientation of the cuticular molecules, as indicated by the positive and negative signals of the IR peaks. This unique property of PM-IRRAS revealed that the alkyl chains of the waxes and the main chains of polysaccharides are oriented almost perpendicular to the leaf surface. The nondestructive, background-free, and environmental gas-free nature of PM-IRRAS allows the structure and chemistry of the leaf cuticle to be studied directly in its native environment.

  14. Fate of plutonium intercepted by leaf surfaces: leachability and translocation to seed and root tissues

    International Nuclear Information System (INIS)

    Cataldo, D.A.; Klepper, E.L.; Craig, D.K.

    1975-01-01

    A low windspeed plant exposure chamber was employed for the generation and deposition of particulate 238 Pu as nitrate, citrate, and oxide (fresh and aged) onto foliage of Phaseolus vulgaris. Physical deposition characteristics and particle sizing were routinely measured and deposition parameters calculated. At wind speeds of 0.42 cm sec -1 , deposition velocities for these compounds were of the order 10 -3 cm sec -1 with deposition rates onto exposed foliage of 0.26 to 0.52 pg 238 Pu cm -2 sec -1 . The fate of surface deposited Pu compounds with respect to chemical modification and leachability was evaluated by leaching with synthetic rainwater and 0.1 percent HNO 3 solutions. Leaching of contaminated foliage with acidified solutions resulted in a 1-to-9 fold increase in Pu removal from foliar surfaces, depending upon chemical form, as compared to rainwater. Sequential leaching of foliage at 1, 7, 14, or 21 days after contamination indicated a reduced leachability of surface deposits with residence time on the leaf. The extent of leaching and concentration of soluble component was dependent on chemical form supplied (Pu-citrate greater than -nitrate greater than -aged oxide greater than -fresh oxide). The bioavailability of Pu as measured by translocation of foliarly deposited plutonium to root and seed tissue was markedly affected by the presence of a solution vector (i.e., simulated rainfall), and also the timing of its application

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

    KAUST Repository

    Houborg, Rasmus

    2013-07-01

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

  16. Glands on the foliar surfaces of tribe Cercideae (Caesapiniodeae, Leguminosae: distribution and taxonomic significance

    Directory of Open Access Journals (Sweden)

    JOAQUIM M. DUARTE-ALMEIDA

    2015-06-01

    Full Text Available Large elongated glands occur on Cercideae leaf surfaces. Leaves of Bauhinia (55 taxa, 53 species, Cercis (1 species, Phanera (1 species, Piliostigma (2 species, Schnella (19 species and Tylosema (1 species were observed to determine location and relative number of glands. They were only observed on the abaxial leaf surface of 42 Bauhinia taxa. The glands were analyzed by light stereomicroscope and scanning electron microscopy. They are large (up to 270 µm long and 115 µm wide and multicellular, containing lipophilic substances, probably volatile oils. Presence or absence and density of the glands in species of Bauhinia may be useful to determine species delimitation or distinction among infraspecific taxa. Higher density of glands is more common in species from "cerrado" (a savanna ecosystem and "caatinga" (a semiarid ecosystem from northeast Brazil areas. Bauhinia species devoid of foliar glands are frequently from humid forests.

  17. Data from the analytical performance of the Abaxis Piccolo Xpress point of care analyzer in whole blood, serum, and plasma

    Directory of Open Access Journals (Sweden)

    Kazunori Murata

    2018-02-01

    Full Text Available The objective of this study was to examine the analytical performance of 14 comprehensive metabolic panel analytes on the Abaxis Piccolo Xpress® Point of Care analyzer in serum, plasma, and whole blood. A method comparison was performed on all three specimen types intended for use on the Piccolo Xpress®: serum, heparinized plasma, and whole blood. This data is also presented in Murata et al. (2015 [1]. This article includes the actual Bland-Altman bias plots of the difference in results obtained for analytes in the comprehensive metabolic panel from the Abaxis Piccolo Xpress and the comparison instrument, the Ortho Vitros. Keywords: Clinical chemistry, Point-of care testing

  18. Response surface optimization of enzymatic hydrolysis of narrow-leaf cattail for bioethanol production

    International Nuclear Information System (INIS)

    Ruangmee, Arrisa; Sangwichien, Chayanoot

    2013-01-01

    Highlights: • The cellulose of pretreated sample was higher than untreated sample. • Lower hemicellulose and lignin were enhanced of hydrolyzed cellulose to sugar. • The predicted result of enzymatic hydrolysis process was fitted by quadratic model. • Predicted data was good agreement with the experimental data; with 95% confidence. - Abstract: Narrow-leaf cattail was employed as lignocellulosic biomass substrate for the investigation of the hydrolysis process of lignocellulosic ethanol. Cellulose saccharification into a high yield of fermentable sugar is an important step in ethanol production. Response surface methodology was utilized in the study of variables affecting enzymatic hydrolysis on the released glucose and xylose. Five levels (−2, −1, 0, +1, +2) of independent variable factors; cellulase (5–25 FPU/g substrate), β-glucosidase (0–20 U/g substrate), hydrolysis temperature (30–50 °C), and hydrolysis time (24–96 h), were randomly setup by using the Design of Experiment program. The significance of the regression model was high; with 95% confidence interval (less than 5% error). The predicted result after optimization was also in good agreement with the experimental data. An optimal condition; 13.50 FPU/g substrate, 16.50 U/g substrate, 50 °C and 24 h, was obtained, yielding a released glucose of 552.9 mg/g substrate (75.6% saccharification) and a released xylose of 74.0 mg/g substrate (45.6% saccharification)

  19. Influence of simulated acid rain on the flowering dogwood (Cornus florida) leaf surface

    Energy Technology Data Exchange (ETDEWEB)

    Brown, D.A. (Auburn Univ., AL (United States)); Windham, M.T.; Trigiano, R.N. (Tennessee Univ., Knoxville, TN (United States)); Anderson, R.L. (United States Dept. of Agriculture, Asheville, NC (United States))

    1994-01-01

    Acidic rainfall has the potential to influence anthracnose incidence and severity in flowering dogwood (Cornus florida L.) of the eastern United States. One-year-old, nursery-grown flowering dogwood seedlings were exposed to 1 cm of simulated rain 10 times over a 42-day period in 1990. Simulated rains were composed of a mixture of salts typical of ambient rainfall in the eastern United States and pH was adjusted to 5.5, 4.5, 3.5, and 2.5 with sulfuric and nitric acids. Samples were cut from the leaf tip, margin, and midvein of rain-treated trees and prepared for scanning electron microscopy. Cuticular cracking, desiccation, and erosion of trichrome surfaces were observed with decreasing pH for all samples. Cuticular erosion due to acid rain has the potential to predispose dogwoods in the eastern United States to anthracnose caused by Discula destructiva sp.nov. (Red.) and an unnamed Discula sp. 25 refs., 4 figs.

  20. Simple microscopic process to determine the pollution level on leaf surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kisser, J; Lehnert, I

    1957-01-01

    For an unbiased determination of the degree of contamination of plants in the sphere of industrial establishments a method was developed by which a qualitative and quantitative fixation of the real dust cover could be found on the spot at any given time. Such a method must also be practicable as a field method and must provide the possibility for collecting the necessary amount of test material in the field in the shortest possible time and by the simplest means. For this purpose two methods were tried: the production of proof films including all contaminations of the leaf surface, and the production of impression preparations, by which the dust cover is picked up in its natural arrangement by an adhesive layer. The latter has proven to be the more efficient method. For the production of impression preparations transparent adhesive tape on a cellulose basis has proved to be very suitable. The making of impression preparations of contaminated leaves by means of the adhesive tape method is described in detail. It consists of the applications on the leaves, the removal of the Scotch tape and the preparation of microscopic preparations of the proofs; this can be done by different means, either by a direct mounting of the proofs on slides or another Scotch tape, or by using different mounting media described separately (no danger of turbidity). Finally some brief indications are given, as to how the preparations should be utilized.

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

    Directory of Open Access Journals (Sweden)

    Yusran Payae

    2009-07-01

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

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

    Science.gov (United States)

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

    2012-01-01

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

  3. 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...

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

    OpenAIRE

    Dr.T.Jayasree; Dr.Shaikh Ubedulla; Dr.Harini K; Dr.Shankar.J

    2014-01-01

    Aim: Piper betel Linn. (Piperaceae) commonly known as betel leaf and the habit of betel chewing is widely prevalent in most parts of India. It is claimed to have aphrodisiac, laxative, antimicrobial, mucolytic, antiinflammatory and euphoric properties and proven antimutagenic and anti-carcinogenic effect. It is commonly observed that chewing of betel leaf produces numbness in the mouth, suggesting a possible local anesthetic effect. This observation prompted us to take this study . The aim...

  5. Comparison of avian biochemical test results with Abaxis VetScan and Hitachi 911 analyzers.

    Science.gov (United States)

    Greenacre, Cheryl B; Flatland, Bente; Souza, Marcy J; Fry, Michael M

    2008-12-01

    To compare results of clinical biochemical analysis using an Abaxis VetScan bench-top analyzer with reagents specifically marketed for avian use and a Hitachi 911 analyzer, plasma (both methods) and whole blood (VetScan method) samples from 20 clinically healthy Hispaniolan Amazon parrots (Amazona ventralis) were analyzed. Correlation between methods was very high (r = 0.9-1.0) for aspartate aminotransferase (AST), calcium, glucose, and uric acid; high (r = 0.7-0.89) for creatine kinase (CK), phosphorus, potassium, and total protein; moderate (r = 0.5-0.69) for globulin; and low (r = 0.3-0.49) for albumin and sodium. VetScan analyzer results for globulin, sodium, and uric acid had a constant negative bias (values below those from the Hitachi method). Based on difference plot analysis, results for AST, calcium, CK, and glucose are comparable. Because 16 of 20 values fell below the lower detection limit of the VetScan analyzer, bile acid data were excluded from analysis. By using a relatively small sample size (0.1 ml whole blood or plasma), the VetScan analyzer offers rapid in-house results, compact size, and ease of operation. For 4 of the most clinically relevant biochemical analytes used in avian medicine (AST, calcium, CK, glucose), it offers reliable values. For an additional 4 analytes (phosphorous, potassium, total protein, uric acid), establishing analyzer-specific reference intervals is recommended. Neither the VetScan nor the Hitachi method is recommended to assess albumin and globulin concentrations.

  6. Dispersal, density dependence, and population dynamics of a fungal microbe on leaf surfaces.

    Science.gov (United States)

    Woody, Scott T; Ives, Anthony R; Nordheim, Erik V; Andrews, John H

    2007-06-01

    Despite the ubiquity and importance of microbes in nature, little is known about their natural population dynamics, especially for those that occupy terrestrial habitats. Here we investigate the dynamics of the yeast-like fungus Aureobasidium pullulans (Ap) on apple leaves in an orchard. We asked three questions. (1) Is variation in fungal population density among leaves caused by variation in leaf carrying capacities and strong density-dependent population growth that maintains densities near carrying capacity? (2) Do resident populations have competitive advantages over immigrant cells? (3) Do Ap dynamics differ at different times during the growing season? To address these questions, we performed two experiments at different times in the growing season. Both experiments used a 2 x 2 factorial design: treatment 1 removed fungal cells from leaves to reveal density-dependent population growth, and treatment 2 inoculated leaves with an Ap strain engineered to express green fluorescent protein (GFP), which made it possible to track the fate of immigrant cells. The experiments showed that natural populations of Ap vary greatly in density due to sustained differences in carrying capacities among leaves. The maintenance of populations close to carrying capacities indicates strong density-dependent processes. Furthermore, resident populations are strongly competitive against immigrants, while immigrants have little impact on residents. Finally, statistical models showed high population growth rates of resident cells in one experiment but not in the other, suggesting that Ap experiences relatively "good" and "bad" periods for population growth. This picture of Ap dynamics conforms to commonly held, but rarely demonstrated, expectations of microbe dynamics in nature. It also highlights the importance of local processes, as opposed to immigration, in determining the abundance and dynamics of microbes on surfaces in terrestrial systems.

  7. Leaf and stem morphoanatomy of Petiveria alliacea.

    Science.gov (United States)

    Duarte, M R; Lopes, J F

    2005-12-01

    Petiveria alliacea is a perennial herb native to the Amazonian region and used in traditional medicine for different purposes, such as diuretic, antispasmodic and anti-inflammatory. The morphoanatomical characterization of the leaf and stem was carried out, in order to contribute to the medicinal plant identification. The plant material was fixed, freehand sectioned and stained either with toluidine blue or astra blue and basic fuchsine. Microchemical tests were also applied. The leaf is simple, alternate and elliptic. The blade exhibits paracytic stomata on the abaxial side, non-glandular trichomes and dorsiventral mesophyll. The midrib is biconvex and the petiole is plain-convex, both traversed by collateral vascular bundles adjoined with sclerenchymatic caps. The stem, in incipient secondary growth, presents epidermis, angular collenchyma, starch sheath and collateral vascular organization. Several prisms of calcium oxalate are seen in the leaf and stem.

  8. Retrieval of Specific Leaf Area From Landsat-8 Surface Reflectance Data Using Statistical and Physical Models

    NARCIS (Netherlands)

    Ali, Abebe Mohammed; Darvishzadeh, R.; Skidmore, Andrew K.

    2017-01-01

    One of the key traits in the assessment of ecosystem functions is a specific leaf area (SLA). The main aim of this study was to examine the potential of new generation satellite images, such as Landsat-8 imagery, for the retrieval of SLA at regional and global scales. Therefore, both statistical and

  9. Composição química da cera epicuticular e caracterização da superfície foliar em genótipos de cana-de-açúcar Chemical composition of epicuticular wax and characterization of leaf surface in sugarcane genotypes

    Directory of Open Access Journals (Sweden)

    E.A. Ferreira

    2005-12-01

    Full Text Available Objetivou-se neste trabalho avaliar a composição química da cera epicuticular e caracterizar a superfície foliar dos cultivares de cana-de-açúcar RB855113 (sensível à mistura de herbicidas trifloxysulfuron-sodium + ametryn, SP80-1842 e SP80-1816, do clone RB957689 (com média sensibilidade à mistura de herbicidas e do cultivar RB867515 (tolerante. A cera epicuticular foi extraída e quantificada e os seus constituintes analisados por cromatografia a gás, acoplada a espectrômetro de massa (CG-EM. Para determinação da composição química, assim como a caracterização da superfície foliar dos cultivares avaliados, amostras de lâmina foliar foram coletadas e submetidas à microscopia eletrônica de varredura, para caracterização das faces adaxial e abaxial. A análise das amostras revelou a presença de hidrocarbonetos, esteróides, ésteres graxos, álcoois e aldeídos. A cera do cultivar sensível à mistura (RB855113 apresentou menor número de componentes químicos e predominância de ésteres graxos de cadeia mais curta que os encontrados nos demais cultivares, bem como pequena proporção de esteróides e hidrocarbonetos. Nos cultivares com média sensibilidade (SP80-1842 e RB867515, a cera apresentou maior proporção de hidrocarbonetos e esteróides. A cera do cultivar RB855113 apresentou polaridade intermediária, porém menos polar que a cera do cultivar RB867515 (tolerante à mistura. Não foram observadas diferenças marcantes entre os cultivares no que se refere à micromorfologia foliar.This study aimed to evaluate the chemical composition of epicuticular wax and to characterize leaf surface in the sugarcane cultivars RB85113 (sensitive to trifloxysulfuron-sodium + ametryn, SP80 1842, SP80 1816, clone RB957689 (with medium sensitivity to trifloxysulfuron-sodium + ametryn and the cultivar RB867515 (tolerant. Epicuticular wax was extracted and quantified, and its contents submitted to gas chromatography coupled to a

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

    Directory of Open Access Journals (Sweden)

    Xiang Li

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

  11. Heterogeneous Photochemistry of Agrochemicals at the Leaf Surface: A Case Study of Plant Activator Acibenzolar-S-methyl.

    Science.gov (United States)

    Sleiman, M; de Sainte Claire, P; Richard, C

    2017-09-06

    The photoreactivity of plant activator benzo(1,2,3)thiadiazole-7-carbothioic acid S-methyl ester (BTH), commonly named acibenzolar-S-methyl, was studied on the surfaces of glass, paraffinic wax films, and apple leaves. Experiments were carried out in a solar simulator using pure and formulated BTH (BION). Surface photoproducts were identified using liquid chromatography coupled with electrospray ionization and high-resolution Orbitrap mass spectrometry, while volatile photoproducts were characterized using an online thermal desorption system coupled to a gas chromatography-mass spectrometry (GC-MS) system. Pure BTH degraded quickly on wax surfaces with a half-life of 5.0 ± 0.5 h, whereas photolysis of formulated BTH was 7 times slower (t 1/2 = 36 ± 14 h). On the other hand, formulated BTH was found to photolyze quickly on detached apple leaves with a half-life of 2.8 h ± 0.4 h. This drastic difference in photoreactivity was attributed to the nature and spreading of the BTH deposit, as influenced by the surfactant and surface characteristics. Abiotic stress of irradiated apple leaf was also shown to produce OH radicals which might contribute to the enhanced photodegradability. Eight surface photoproducts were identified, whereas GC-MS analyses revealed the formation of gaseous dimethyl disulfide and methanethiol. The yield of dimethyl disulfide ranged between 1.5% and 12%, and a significant fraction of dimethyl disulfide produced was found to be absorbed by the leaf. This is the first study to report on the formation of volatile chemicals and OH radicals during agrochemical photolysis on plant surfaces. The developed experimental approach can provide valuable insights into the heterogeneous photoreactivity of sprayed agrochemicals and could help improve dissipation models.

  12. Epidemiology and Control of Strawberry Bacterial Angular Leaf Spot Disease Caused by Xanthomonas fragariae

    Directory of Open Access Journals (Sweden)

    Da-Ran Kim

    2016-08-01

    Full Text Available Strawberry bacterial angular leaf spot (ALS disease, caused by Xanthomonas fragariae has become increasingly problematic in the strawberry agro-industry. ALS causes small angular water-soaked lesions to develop on the abaxial leaf surface. Studies reported optimum temperature conditions for X. fragariae are 20°C and the pathogen suffers mortality above 32°C. However, at the nursery stage, disease symptoms have been observed under high temperature conditions. In the present study, results showed X. fragariae transmission was via infected maternal plants, precipitation, and sprinkler irrigation systems. Systemic infections were detected using X. fragariae specific primers 245A/B and 295A/B, where 300-bp and 615-bp were respectively amplified. During the nursery stage (from May to August, the pathogen was PCR detected only in maternal plants, but not in soil or irrigation water through the nursery stage. During the cultivation period, from September to March, the pathogen was detected in maternal plants, progeny, and soil, but not in water. Additionally, un-infected plants, when planted with infected plants were positive for X. fragariae via PCR at the late cultivation stage. Chemical control for X. fragariae with oxolinic acid showed 87% control effects against the disease during the nursery period, in contrast to validamycin-A, which exhibited increased efficacy against the disease during the cultivation stage (control effect 95%. To our knowledge, this is the first epidemiological study of X. fragariae in Korean strawberry fields.

  13. Pathogenicity of Fusarium avenaceum isolates to tulip leaves assessed on leaf disks

    Directory of Open Access Journals (Sweden)

    Agnieszka Piwoni

    2013-12-01

    Full Text Available The purpose of this study was to investigate the pathogenicity of 14 Fusarium avenaceum (Giberella avenacea isolates, obtained from tulip plantations located in Puławy region, to leaves of tulip cv. Apeldoorn. Mycelial plugs 3 mm in diameter from the margins of the colonies growing on PDA and SNA were placed on 20 mm disks cut from tulip leaves. The disks were placed abaxial surface up, in Petri dishes on top of filter paper soaked with 100 mg/l gibberellic acid to retard leaf senescence. There were 5 replications for each isolate. Leaves in each Petń dish were inoculated with one isolate. Plates were incubated at 20°C and lesion diameters were measured after 4 days. The pathogenicity of investigated isolates was compared by measuring lesion development on tulip leaves. All of isolates colonized leaves disks succesfull - causing after 4 days necrotic lesions and sporulating after 14 days what indicated that an infection had occurred. There were significant differences in lesions size among isolates. Isolates: 27, 1, 2, 48 and 3 caused largest lesions at mean size from 150 mm2 to 163 mm2 what indicates their high pathogenicity. Less pathogenic were isolates: 28, 42, 7 and 72 caused lesions at mean size from 46 mm2 to 97 mm~2. On average, mycelial plugs taken from PDA medium colonized leaf disks more efficient in comparison to them taken from SNA, that caused smaller lesions.

  14. Effect of enhanced UV-B radiation of adaxial leaf surface micromorphology and epicuticular wax biosynthesis of sugar maple

    International Nuclear Information System (INIS)

    Gordon, D.C.; Percy, K.E.; Riding, R.T.

    1998-01-01

    Sugar maple (Acer saccharum [Marsh.]) seedlings were exposed to UV-B BE ranging from 0.61 kJ m -2 d -1 to 12.48 kJ m -2 d -1 . Increasing UV-B intensity was associated with changes in micromorphological characteristics of the adaxial leaf surface. In vivo incorporation of [1- 14 C] acetate into sugar maple adaxial leaf surface epicuticular wax indicated (p<0.05) a UV-B sensitivity threshold at or near 6.2 kJ m -2 d -1 . Exposure to dosages greater than 6.2 kJ m -2 d -1 resulted in a significant (p<0.05) decrease in wax biosynthesis. The proportion of [1- 14 C] acetate incorporated into each of the different epicuticular wax classes changed with increasing UV-B. Incorporation of [1- 14 C] acetate into alkyl esters decreased while incorporation into alkanes increased with increasing UV-B dose. The effects of enhanced UV-B dose recorded in this experiment may have implications for cuticle function. (author)

  15. Real-time mapping of salt glands on the leaf surface of Cynodon dactylon L. using scanning electrochemical microscopy.

    Science.gov (United States)

    Parthasarathy, Meera; Pemaiah, Brindha; Natesan, Ravichandran; Padmavathy, Saralla R; Pachiappan, Jayaraman

    2015-02-01

    Salt glands are specialized organelles present in the leaf tissues of halophytes, which impart salt-tolerance capability to the plant species. These glands are usually identified only by their morphology using conventional staining procedures coupled with optical microscopy. In this work, we have employed scanning electrochemical microscopy to identify the salt glands not only by their morphology but also by their salt excretion behavior. Bermuda grass (Cynodon dactylon L.) species was chosen for the study as they are known to be salt-tolerant and contain salt glands on leaf surfaces. Scanning electrochemical microscopy performed in sodium chloride medium in the presence and absence of potassium ferrocyanide as redox mediator, reveals the identity of salt glands. More insight into the ion expulsion behavior of these glands was obtained by mapping lateral and vertical variations in ion concentrations using surface impedance measurements which indicated five times higher resistance over the salt glands compared to the surrounding tissues and bulk solution. The protocol could be used to understand the developmental processes in plants grown in different soil/water conditions in order to improve salt tolerance of food crops by genetic engineering and hence improve their agricultural productivity.

  16. The Effect of Leaf Litter Cover on Surface Runoff and Soil Erosion in Northern China

    Science.gov (United States)

    Li, Xiang; Niu, Jianzhi; Xie, Baoyuan

    2014-01-01

    The role of leaf litter in hydrological processes and soil erosion of forest ecosystems is poorly understood. A field experiment was conducted under simulated rainfall in runoff plots with a slope of 10%. Two common types of litter in North China (from Quercus variabilis, representing broadleaf litter, and Pinus tabulaeformis, representing needle leaf litter), four amounts of litter, and five rainfall intensities were tested. Results revealed that the litter reduced runoff and delayed the beginning of runoff, but significantly reduced soil loss (prunoff yield was 29.5% and 31.3% less than bare-soil plot, and for Q. variabilis and P. tabulaeformis, respectively, and average sediment yield was 85.1% and 79.9% lower. Rainfall intensity significantly affected runoff (R = 0.99, prunoff reduction by litter decreased considerably. Runoff yield and the runoff coefficient increased dramatically by 72.9 and 5.4 times, respectively. The period of time before runoff appeared decreased approximately 96.7% when rainfall intensity increased from 5.7 to 75.6 mm h−1. Broadleaf and needle leaf litter showed similarly relevant effects on runoff and soil erosion control, since no significant differences (p≤0.05) were observed in runoff and sediment variables between two litter-covered plots. In contrast, litter mass was probably not a main factor in determining runoff and sediment because a significant correlation was found only with sediment in Q. variabilis litter plot. Finally, runoff yield was significantly correlated (prunoff and erosion processes was crucial, and both rainfall intensity and litter characteristics had an impact on these processes. PMID:25232858

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

    Science.gov (United States)

    Li, Xiang; Niu, Jianzhi; Xie, Baoyuan

    2014-01-01

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

  18. In situ determination of the depuration of three- and four-ringed polycyclic aromatic hydrocarbons co-adsorbed onto mangrove leaf surfaces

    International Nuclear Information System (INIS)

    Sun, Haifeng; Shi, Jing; Guo, Shuai; Zhang, Yong; Duan, Lusha

    2016-01-01

    A dual-wavelength fiber-optic fluorimetry for the in situ simultaneous determinations of fluorene (Flu), phenanthrene (Phe) and pyrene (Pyr) adsorbed onto the leaf surfaces of living Avicennia marina (Am) seedling were developed and used to study the depuration kinetics of the three PAHs, adsorbed individually or mixed together, onto living Am leaf surfaces. Limits of detection for the in situ measurements of adsorbed Flu, Phe and Pyr were 4.62, 2.75 and 1.38 ng spot"−"1, respectively. The depuration kinetics of the three selected polycyclic aromatic hydrocarbons (PAHs) are divided into rapid and slow phases; both phases followed the same first-order kinetics with relative clearance rates of Flu > Phe > Pyr during the rapid phase, and a clearance rate order of Pyr > Flu > Phe during the slow phase. For the three PAHs co-adsorbed on living Am leaf surfaces, a significant synergistic effect was detected during the rapid phase clearance; conversely, an antagonistic effect was observed during the slow phase. However, the synergistic effect dominated during both phases of the depuration process, and the co-adsorption of PAHs promoted the clearance of all three compounds from the mangrove leaf surfaces. These findings demonstrate a novel analytical method for in situ characterization of multiple PAHs adsorbed onto the plant surfaces. - Highlights: • A novel method for the in situ determination of multi-component PAHs was developed. • Synergistic and antagonistic effects separately occurred over rapid and slow phases. • The clearance of all three PAHs from leaf surfaces was promoted by co-adsorption. - The co-adsorption of PAHs promoted the depuration of all three compounds from the mangrove leaf surfaces.

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

    Directory of Open Access Journals (Sweden)

    Mohammad I. Jahirul

    2014-08-01

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

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

    Directory of Open Access Journals (Sweden)

    Lyudmila I. Buyun

    2013-04-01

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

  1. Superhydrophobic surfaces fabricated by femtosecond laser with tunable water adhesion: from lotus leaf to rose petal.

    Science.gov (United States)

    Long, Jiangyou; Fan, Peixun; Gong, Dingwei; Jiang, Dafa; Zhang, Hongjun; Li, Lin; Zhong, Minlin

    2015-05-13

    Superhydrophobic surfaces with tunable water adhesion have attracted much interest in fundamental research and practical applications. In this paper, we used a simple method to fabricate superhydrophobic surfaces with tunable water adhesion. Periodic microstructures with different topographies were fabricated on copper surface via femtosecond (fs) laser irradiation. The topography of these microstructures can be controlled by simply changing the scanning speed of the laser beam. After surface chemical modification, these as-prepared surfaces showed superhydrophobicity combined with different adhesion to water. Surfaces with deep microstructures showed self-cleaning properties with extremely low water adhesion, and the water adhesion increased when the surface microstructures became flat. The changes in surface water adhesion are attributed to the transition from Cassie state to Wenzel state. We also demonstrated that these superhydrophobic surfaces with different adhesion can be used for transferring small water droplets without any loss. We demonstrate that our approach provides a novel but simple way to tune the surface adhesion of superhydrophobic metallic surfaces for good potential applications in related areas.

  2. Leaf surface structures enable the endemic Namib desert grass Stipagrostis sabulicola to irrigate itself with fog water.

    Science.gov (United States)

    Roth-Nebelsick, A; Ebner, M; Miranda, T; Gottschalk, V; Voigt, D; Gorb, S; Stegmaier, T; Sarsour, J; Linke, M; Konrad, W

    2012-08-07

    The Namib grass Stipagrostis sabulicola relies, to a large degree, upon fog for its water supply and is able to guide collected water towards the plant base. This directed irrigation of the plant base allows an efficient and rapid uptake of the fog water by the shallow roots. In this contribution, the mechanisms for this directed water flow are analysed. Stipagrostis sabulicola has a highly irregular surface. Advancing contact angle is 98° ± 5° and the receding angle is 56° ± 9°, with a mean of both values of approximately 77°. The surface is thus not hydrophobic, shows a substantial contact angle hysteresis and therefore, allows the development of pinned drops of a substantial size. The key factor for the water conduction is the presence of grooves within the leaf surface that run parallel to the long axis of the plant. These grooves provide a guided downslide of drops that have exceeded the maximum size for attachment. It also leads to a minimum of inefficient drop scattering around the plant. The combination of these surface traits together with the tall and upright stature of S. sabulicola contributes to a highly efficient natural fog-collecting system that enables this species to thrive in a hyperarid environment.

  3. Leaf surface structures enable the endemic Namib desert grass Stipagrostis sabulicola to irrigate itself with fog water

    Science.gov (United States)

    Roth-Nebelsick, A.; Ebner, M.; Miranda, T.; Gottschalk, V.; Voigt, D.; Gorb, S.; Stegmaier, T.; Sarsour, J.; Linke, M.; Konrad, W.

    2012-01-01

    The Namib grass Stipagrostis sabulicola relies, to a large degree, upon fog for its water supply and is able to guide collected water towards the plant base. This directed irrigation of the plant base allows an efficient and rapid uptake of the fog water by the shallow roots. In this contribution, the mechanisms for this directed water flow are analysed. Stipagrostis sabulicola has a highly irregular surface. Advancing contact angle is 98° ± 5° and the receding angle is 56° ± 9°, with a mean of both values of approximately 77°. The surface is thus not hydrophobic, shows a substantial contact angle hysteresis and therefore, allows the development of pinned drops of a substantial size. The key factor for the water conduction is the presence of grooves within the leaf surface that run parallel to the long axis of the plant. These grooves provide a guided downslide of drops that have exceeded the maximum size for attachment. It also leads to a minimum of inefficient drop scattering around the plant. The combination of these surface traits together with the tall and upright stature of S. sabulicola contributes to a highly efficient natural fog-collecting system that enables this species to thrive in a hyperarid environment. PMID:22356817

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

    Directory of Open Access Journals (Sweden)

    Barbara Dyki

    2014-01-01

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

  5. [Leaf micrografic anatomy of the Neotropical palm Bactris gasipaes (Arecaceae)].

    Science.gov (United States)

    Chaimsohn, Francisco Paulo; Montiel, Mayra; Villalobos, Enrique; Mora Urpi, Jorge

    2008-06-01

    The economic importance of the palm Bactris gasipaes is growing in the Neotropoical region. We collected leaflets from plants under a chemical fertilization regime and a population of 5000 plants per hectare, in Costa Rica. The variety, Diamantes 10, has an ascendency fom the upper Amazon basin. We used Harries hematoxiline, eocine and standard light microscopy techniques. The presence of raphids and buliform cells was confirmed for the abaxial surface of the leaflets and for the hypodermic tissue on both sides. The absence of the Krantz anatomy was confirmed in consistence with former observations about the C3 photosynthesis in other species of Palmaceae. The average stomatal density on the abaxial surface was 96.87 +/- 16.31 stomata.mm(-2) and 14.20 +/- 4.05 in the adaxial surface.

  6. 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.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  8. Solar UV Irradiation-Induced Production of Greenhouse Gases from Plant Surfaces: From Leaf to Earth

    DEFF Research Database (Denmark)

    Mikkelsen, Teis Nørgaard; Bruhn, Dan; Ambus, Per

    2016-01-01

    -methane volatile organic compounds (NMVOC), NOx and N2O. This gas production, near or at the plant surface, is a new discovery and is normally not included in emission budgets (e.g. by the Intergovernmental Panel on Climate Change, IPCC) due to a lack of information with respect to validation and upscaling. For CH...

  9. Physical and mechanical properties of spinach for whole-surface online imaging inspection

    Science.gov (United States)

    Tang, Xiuying; Mo, Chang Y.; Chan, Diane E.; Peng, Yankun; Qin, Jianwei; Yang, Chun-Chieh; Kim, Moon S.; Chao, Kuanglin

    2011-06-01

    The physical and mechanical properties of baby spinach were investigated, including density, Young's modulus, fracture strength, and friction coefficient. The average apparent density of baby spinach leaves was 0.5666 g/mm3. The tensile tests were performed using parallel, perpendicular, and diagonal directions with respect to the midrib of each leaf. The test results showed that the mechanical properties of spinach are anisotropic. For the parallel, diagonal, and perpendicular test directions, the average values for the Young's modulus values were found to be 2.137MPa, 1.0841 MPa, and 0.3914 MPa, respectively, and the average fracture strength values were 0.2429 MPa, 0.1396 MPa, and 0.1113 MPa, respectively. The static and kinetic friction coefficient between the baby spinach and conveyor belt were researched, whose test results showed that the average coefficients of kinetic and maximum static friction between the adaxial (front side) spinach leaf surface and conveyor belt were 1.2737 and 1.3635, respectively, and between the abaxial (back side) spinach leaf surface and conveyor belt were 1.1780 and 1.2451 respectively. These works provide the basis for future development of a whole-surface online imaging inspection system that can be used by the commercial vegetable processing industry to reduce food safety risks.

  10. Process parameter and surface morphology of pineapple leaf electrospun nanofibers (PALF)

    Science.gov (United States)

    Surip, S. N.; Aziz, F. M. A.; Bonnia, N. N.; Sekak, K. A.; Zakaria, M. N.

    2017-09-01

    In recent times, nanofibers have attracted the attention of researchers due to their pronounced micro and nano structural characteristics that enable the development of advanced materials that have sophisticated applications. The production of nanofibers by the electrospinning process is influenced both by the electrostatic forces and the viscoelastic behavior of the polymer. Process parameters, like solution feed rate, applied voltage, nozzle-collector distance, and spinning environment, and material properties, like solution concentration, viscosity, surface tension, conductivity, and solvent vapor pressure, influence the structure and properties of electrospun nanofibers. Significant work has been done to characterize the properties of PALF nanofibers as a function of process and material parameters.

  11. Epiderme dos segmentos foliares de Mauritia flexuosa L. f. (Arecaceae em três fases de desenvolvimento Epidermis of leaf segments from Mauritia flexuosaL. f. (Arecaceae on three phases of development

    Directory of Open Access Journals (Sweden)

    Mahedy Araújo Bastos Passos

    2006-12-01

    Full Text Available São apresentados os dados anatômicos da epiderme dos segmentos foliares de Mauritia flexuosa L. f. (Arecaceae em três fases do desenvolvimento. Os segmentos foliares foram analisados em toda a extensão do limbo. As células intercostais da epiderme das faces adaxial e abaxial evidenciam-se com paredes sinuosas, retangulares e orientadas longitudinalmente em relação ao eixo do segmento foliar com acentuada presença de corpos de sílica esférico-espinulosos. As células epidérmicas da região costal de ambas as faces apresentam paredes retas e variam entre curtas, longas e arredondadas. Os tricomas são simples, unicelulares, longos, com base mais alargada. Os segmentos foliares de M. flexuosa são anfiestomáticos com estômatos tetracíticos. Em secção transversal a epiderme foliar é uniestratificada com câmara subestomática ampla. Os resultados obtidos não demonstraram variações expressivas entre as três fases de desenvolvimento e os caracteres encontrados parecem ser comuns a outras palmeiras.Anatomic data on the epidermis leaf segments from Mauritia flexuosa L. f. (Arecaceae are presented on three phases of development. Leaf segments were analyzed on the all extension of leaf. Both adaxial and abaxial epidermal cells stand out with sinuous walls, rectangular and longitudinally oriented to the foliar axis with the marked presence of spherical- spiny silica bodies. The back epidermal cells of both surfaces present straight walls and vary among short, long and round. Trichomes are unicellular, simple, long, with a wider base. Leaf segments from M. flexuosa are anphistomatic with tetracitic type stomats. In a cross-section the leaf skin is unistratified with a broad substimatic chamber. The findings obtained showed no significant variations among the three phases of development and the characters that were found appear to be common on other palm trees.

  12. The utility of Bambusoideae (Poaceae, Poales leaf blade anatomy for identification and systematics

    Directory of Open Access Journals (Sweden)

    T. D. Leandro

    Full Text Available Abstract Bambusoideae is a diverse subfamily that includes herbaceous (Olyreae and woody (Arundinarieae and Bambuseae bamboos. Species within Bambusae are particularly difficult to identify due to their monocarpic lifecycle and the often long durations between mass flowering events; whereas the herbaceous bamboos are pluricarpic, but often are found with no reproductive structures. The leaf blade anatomy of 16 sympatric species of native Brazilian bamboos (Olyreae and Bambuseae from the Atlantic Rainforest was studied in order to detect useful features for their identification. All the studied species share the following features: epidermis with a single stratum of cells; adaxial bulliform cells; mesophyll with arm cells, rosette cells, and fusoid cells; and collateral vascular bundles. Herbaceous bamboos share two features: papillae scattered on the abaxial surface and parallel-sided arrays of bulliform cells; whereas woody bamboos share: centrally organized papillae and fan-shaped arrays of bulliform cells. Also within the woody bamboos, intercostal fibers and a midrib with only one vascular bundle (simple midrib characterize the subtribe Arthrostylidiinae; whereas a midrib with more than one vascular bundle (complex midrib and a stomatal apparatus with two pappilae per subsidiary cell characterize the subtribe Chusqueinae. There are also diagnostic features for the sampled species, such as: papillae shape, and the outline and structure of the midrib. An identification key for all the studied species is provided based on the anatomical features.

  13. Comparison of computer assisted surgery with conventional technique for treatment of abaxial distal phalanx fractures in horses: an in vitro study.

    Science.gov (United States)

    Rossol, Melanie; Gygax, Diego; Andritzky-Waas, Juliane; Zheng, Guoyan; Lischer, Christoph J; Zhang, Xuan; Auer, Joerg A

    2008-01-01

    To (1) evaluate and compare computer-assisted surgery (CAS) with conventional screw insertion (conventional osteosynthesis [COS]) for treatment of equine abaxial distal phalanx fractures; (2) compare planned screw position with actual postoperative position; and (3) determine preferred screw insertion direction. Experimental study. Cadaveric equine limbs (n=32). In 8 specimens each, a 4.5 mm cortex bone screw was inserted in lag fashion in dorsopalmar (plantar) direction using CAS or COS. In 2 other groups of 8, the screws were inserted in opposite direction. Precision of CAS was determined by comparison of planned and actual screw position. Preferred screw direction was also assessed for CAS and COS. In 4 of 6 direct comparisons, screw positioning was significantly better with CAS. Results of precision analysis for screw position were similar to studies published in human medicine. None of evaluated criteria identified a preferred direction for screw insertion. For abaxial fractures of the distal phalanx, superior precision in screw position is achieved with CAS technique compared with COS technique. Abaxial fractures of the distal phalanx lend themselves to computer-assisted implantation of 1 screw in a dorsopalmar (plantar) direction. Because of the complex anatomic relationships, and our results, we discourage use of COS technique for repair of this fracture type.

  14. Acquisition and Diversification of Cladodes: Leaf-Like Organs in the Genus Asparagus[W

    Science.gov (United States)

    Nakayama, Hokuto; Yamaguchi, Takahiro; Tsukaya, Hirokazu

    2012-01-01

    The genus Asparagus is unusual in producing axillary, determinate organs called cladodes, which may take on either a flattened or cylindrical form. Here, we investigated the evolution of cladodes to elucidate the mechanisms at play in the diversification of shoot morphology. Our observations of Asparagus asparagoides, which has leaf-like cladodes, showed that its cladodes are anatomically and developmentally similar to leaves but differ in the adaxial/abaxial polarity of the vasculature. In addition to the expression of an ortholog of KNAT1, orthologous genes that are normally expressed in leaves, ASYMMETRIC LEAVES1 and HD-ZIPIII, were found to be expressed in cladode primordia in a leaf-like manner. The cylindrical cladodes of Asparagus officinalis showed largely similar expression patterns but showed evidence of being genetically abaxialized. These results provide evidence that cladodes are modified axillary shoots, suggest that the co-option of preexisting gene networks involved in leaf development transferred the leaf-like form to axillary shoots, and imply that altered expression of leaf polarity genes led to the evolution of cylindrical cladodes in the A. officinalis clade. PMID:22415273

  15. Acquisition and diversification of cladodes: leaf-like organs in the genus Asparagus.

    Science.gov (United States)

    Nakayama, Hokuto; Yamaguchi, Takahiro; Tsukaya, Hirokazu

    2012-03-01

    The genus Asparagus is unusual in producing axillary, determinate organs called cladodes, which may take on either a flattened or cylindrical form. Here, we investigated the evolution of cladodes to elucidate the mechanisms at play in the diversification of shoot morphology. Our observations of Asparagus asparagoides, which has leaf-like cladodes, showed that its cladodes are anatomically and developmentally similar to leaves but differ in the adaxial/abaxial polarity of the vasculature. In addition to the expression of an ortholog of KNAT1, orthologous genes that are normally expressed in leaves, asymmetric leaves1 and HD-ZIPIII, were found to be expressed in cladode primordia in a leaf-like manner. The cylindrical cladodes of Asparagus officinalis showed largely similar expression patterns but showed evidence of being genetically abaxialized. These results provide evidence that cladodes are modified axillary shoots, suggest that the co-option of preexisting gene networks involved in leaf development transferred the leaf-like form to axillary shoots, and imply that altered expression of leaf polarity genes led to the evolution of cylindrical cladodes in the A. officinalis clade.

  16. A novel growth-promoting microbe, Methylobacterium funariae sp. nov., isolated from the leaf surface of a common moss.

    Science.gov (United States)

    Schauer, S; Kutschera, U

    2011-04-01

    Land plants (embryophytes) evolved in the presence of prokaryotic microbes. As a result, numerous mutually beneficial associations (symbioses) developed that can be analyzed using a variety of methods. Here we describe the isolation and characterization of a new pink-pigmented facultatively methylotrophic symbiotic bacterium of the genus Methylobacterium (laboratory strain F3.2) that was isolated from the gametophytic phylloids of the common cord moss Funaria hygrometrica Hedw. Plantlets were collected in the field and analyzed in the laboratory. Colonies of methylobacteria were obtained by the agar-impression-method. Based on its unique phenotype (the bacterial cells are characterized by fimbriae-like appendages), a comparative 16S rRNA gene (DNA) sequence analysis, and an average DNA-DNA hybridization value of 8,4 %, compared with its most closely related sister taxon, this isolate is described as a new species, Methylobacterium funariae sp. nov. (type strain F3.2). This new epiphytic bacterium inhabits the leaf surface of "primitive" land plants such as mosses and interacts with its host organism via the secretion of phytohormones (cytokinines, auxins). These external signals are perceived by the plant cells that divide and grow more rapidly than in the absence of their prokaryotic phytosymbionts. We suggest that M. funariae sp. nov. uses methanol emitted from the stomatal pores as principal carbon source for cell metabolism. However, our novel data indicate that, in this unique symbiotic plant-microbe interaction, the uptake of amino acids leached from the surface of the epidermal cells of the green host organism may be of importance as microbial carbon- and nitrogen-source.

  17. A novel growth-promoting microbe, Methylobacterium funariae sp. nov., isolated from the leaf surface of a common moss

    Science.gov (United States)

    Schauer, S

    2011-01-01

    Land plants (embryophytes) evolved in the presence of prokaryotic microbes. As a result, numerous mutually beneficial associations (symbioses) developed that can be analyzed using a variety of methods. Here we describe the isolation and characterization of a new pink-pigmented facultatively methylotrophic symbiotic bacterium of the genus Methylobacterium (laboratory strain F3.2) that was isolated from the gametophytic phylloids of the common cord moss Funaria hygrometrica Hedw. Plantlets were collected in the field and analyzed in the laboratory. Colonies of methylobacteria were obtained by the agar-impression-method. Based on its unique phenotype (the bacterial cells are characterized by fimbriae-like appendages), a comparative 16S rRNA gene (DNA) sequence analysis and an average DNA-DNA hybridization value of 8.4%, compared with its most closely related sister taxon, this isolate is described as a new species, Methylobacterium funariae sp. nov. (type strain F3.2). This new epiphytic bacterium inhabits the leaf surface of “primitive” land plants such as mosses and interacts with its host organism via the secretion of phytohormones (cytokinines, auxins). These external signals are perceived by the plant cells that divide and grow more rapidly than in the absence of their prokaryotic phytosymbionts. We suggest that M. funariae sp. nov. uses methanol emitted from the stomatal pores as principal carbon source for cell metabolism. However, our novel data indicate that, in this unique symbiotic plant-microbe interaction, the uptake of amino acids leached from the surface of the epidermal cells of the green host organism may be of importance as microbial carbon- and nitrogen-source. PMID:21673511

  18. Statistical optimization for alkali pretreatment conditions of narrow-leaf cattail by response surface methodology

    Directory of Open Access Journals (Sweden)

    Arrisa Ruangmee

    2013-08-01

    Full Text Available Response surface methodology with central composite design was applied to optimize alkali pretreatment of narrow-leafcattail (Typha angustifolia. Joint effects of three independent variables; NaOH concentration (1-5%, temperature (60-100 ºC,and reaction time (30-150 min, were investigated to evaluate the increase in and the improvement of cellulosic componentscontained in the raw material after pretreatment. The combined optimum condition based on the cellulosic content obtainedfrom this study is: a concentration of 5% NaOH, a reaction time of 120 min, and a temperature of 100 ºC. This result has beenanalyzed employing ANOVA with a second order polynomial equation. The model was found to be significant and was able topredict accurately the response of strength at less than 5% error. Under this combined optimal condition, the desirable cellulosic content in the sample increased from 38.5 to 68.3%, while the unfavorable hemicellulosic content decreased from 37.6 to7.3%.

  19. 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

    -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...... 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...

  20. Insect Analogue to the Lotus Leaf: A Planthopper Wing Membrane Incorporating a Low-Adhesion, Nonwetting, Superhydrophobic, Bactericidal, and Biocompatible Surface.

    Science.gov (United States)

    Watson, Gregory S; Green, David W; Cribb, Bronwen W; Brown, Christopher L; Meritt, Christopher R; Tobin, Mark J; Vongsvivut, Jitraporn; Sun, Mingxia; Liang, Ai-Ping; Watson, Jolanta A

    2017-07-19

    Nature has produced many intriguing and spectacular surfaces at the micro- and nanoscales. These small surface decorations act for a singular or, in most cases, a range of functions. The minute landscape found on the lotus leaf is one such example, displaying antiwetting behavior and low adhesion with foreign particulate matter. Indeed the lotus leaf has often been considered the "benchmark" for such properties. One could expect that there are animal counterparts of this self-drying and self-cleaning surface system. In this study, we show that the planthopper insect wing (Desudaba danae) exhibits a remarkable architectural similarity to the lotus leaf surface. Not only does the wing demonstrate a topographical likeness, but some surface properties are also expressed, such as nonwetting behavior and low adhering forces with contaminants. In addition, the insect-wing cuticle exhibits an antibacterial property in which Gram-negative bacteria (Porphyromonas gingivalis) are killed over many consecutive waves of attacks over 7 days. In contrast, eukaryote cell associations, upon contact with the insect membrane, lead to a formation of integrated cell sheets (e.g., among human stem cells (SHED-MSC) and human dermal fibroblasts (HDF)). The multifunctional features of the insect membrane provide a potential natural template for man-made applications in which specific control of liquid, solid, and biological contacts is desired and required. Moreover, the planthopper wing cuticle provides a "new" natural surface with which numerous interfacial properties can be explored for a range of comparative studies with both natural and man-made materials.

  1. A genetic link between epigenetic repressor AS1-AS2 and a putative small subunit processome in leaf polarity establishment of Arabidopsis

    Directory of Open Access Journals (Sweden)

    Yoko Matsumura

    2016-07-01

    Full Text Available Although the DEAD-box RNA helicase family is ubiquitous in eukaryotes, its developmental role remains unelucidated. Here, we report that cooperative action between the Arabidopsis nucleolar protein RH10, an ortholog of human DEAD-box RNA helicase DDX47, and the epigenetic repressor complex of ASYMMETRIC-LEAVES1 (AS1 and AS2 (AS1-AS2 is critical to repress abaxial (ventral genes ETT/ARF3 and ARF4, which leads to adaxial (dorsal development in leaf primordia at shoot apices. Double mutations of rh10-1 and as2 (or as1 synergistically up-regulated the abaxial genes, which generated abaxialized filamentous leaves with loss of the adaxial domain. DDX47 is part of the small subunit processome (SSUP that mediates rRNA biogenesis. In rh10-1 we found various defects in SSUP-related events, such as: accumulation of 35S/33S rRNA precursors; reduction in the 18S/25S ratio; and nucleolar hypertrophy. Double mutants of as2 with mutations of genes that encode other candidate SSUP-related components such as nucleolin and putative rRNA methyltransferase exhibited similar synergistic defects caused by up-regulation of ETT/ARF3 and ARF4. These results suggest a tight link between putative SSUP and AS1-AS2 in repression of the abaxial-determining genes for cell fate decisions for adaxial development.

  2. Assimilation of Leaf Area Index and Soil Wetness Index into the ISBA-A-gs land surface model over France

    Science.gov (United States)

    Barbu, A. L.; Calvet, J.-C.; Lafont, S.

    2012-04-01

    The development of a Land Data Assimilation System (LDAS) dedicated to carbon and water cycles is considered as a key aspect for monitoring activities of terrestrial carbon fluxes. It allows the assimilation of biophysical products in order to reduce the bias between the model simulations and the observations and have a positive impact on carbon and water fluxes. This work shows the benefits of data assimilation of Earth observations for the monitoring of vegetation status and carbon fluxes, in the framework of the GEOLAND2 project, co-funded by the European Commission within the GMES initiative in FP7. In this study, the SURFEX modelling platform developed at Meteo-France is used for describing the continental vegetation state, surface fluxes and soil moisture. It consists of the land surface model ISBA-A-gs that simulates photosynthesis and plant growth. The vegetation biomass and Leaf Area Index (LAI) evolve dynamically in response to weather and climate conditions. The ECOCLIMAP database provides detailed information about the land cover at a resolution of 1 km. Over the France domain, the most present ecosystem types are grasslands (32%), C3 crop lands (24%), deciduous forest (20%), bare soil (11%), and C4 crop lands (8%).The model also includes a representation of the soil moisture stress with two different types of drought responses for herbaceous vegetation and forests. A version of the Extended Kalman Filter (EKF) scheme is developed for the joint assimilation of satellite-derived surface soil moisture from ASCAT-25 km product, namely Soil Wetness Index (SWI-01) developed by TU-Wien, and remote sensing LAI product provided by GEOLAND2. The GEOLAND2 LAI product is derived from CYCLOPES V3.1 and MODIS collection 5 data. It is more consistent with an effective LAI for low LAI and close to the actual LAI for high values. The assimilation experiment was conducted across France at a spatial resolution of 8 km. The study period ranges from July 2007 to December

  3. Leaf reflectance variation along a vertical crown gradient of two deciduous tree species in a Belgian industrial habitat

    International Nuclear Information System (INIS)

    Khavaninzadeh, Ali Reza; Veroustraete, Frank; Van Wittenberghe, Shari; Verrelst, Jochem; Samson, Roeland

    2015-01-01

    The reflectometry of leaf asymmetry is a novel approach in the bio-monitoring of tree health in urban or industrial habitats. Leaf asymmetry responds to the degree of environmental pollution and reflects structural changes in a leaf due to environmental pollution. This paper describes the boundary conditions to scale up from leaf to canopy level reflectance, by describing the variability of adaxial and abaxial leaf reflectance, hence leaf asymmetry, along the crown height gradients of two tree species. Our findings open a research pathway towards bio-monitoring based on the airborne remote sensing of tree canopies and their leaf asymmetric properties. - Highlights: • Reflectometry of leaf asymmetry is a novel approach in tree health bio-monitoring. • Leaf asymmetry reflects degrees of structural changes by environmental pollution. • Conditions to scale up from leaf to canopy level reflectance are described. • A research pathway is opened towards airborne pollution bio-assessment. - Tree leaf asymmetry responds to the degree of environmental pollution and reflects leaf structural changes differentially according to species and height in the crown

  4. Arabidopsis ketoacyl-CoA synthase 16 (KCS16) forms C36 /C38 acyl precursors for leaf trichome and pavement surface wax.

    Science.gov (United States)

    Hegebarth, Daniela; Buschhaus, Christopher; Joubès, Jérôme; Thoraval, Didier; Bird, David; Jetter, Reinhard

    2017-09-01

    The aliphatic waxes sealing plant surfaces against environmental stress are generated by fatty acid elongase complexes, each containing a β-ketoacyl-CoA synthase (KCS) enzyme that catalyses a crucial condensation forming a new C─C bond to extend the carbon backbone. The relatively high abundance of C 35 and C 37 alkanes derived from C 36 and C 38 acyl-CoAs in Arabidopsis leaf trichomes (relative to other epidermis cells) suggests differences in the elongation machineries of different epidermis cell types, possibly involving KCS16, a condensing enzyme expressed preferentially in trichomes. Here, KCS16 was found expressed primarily in Arabidopsis rosette leaves, flowers and siliques, and the corresponding protein was localized to the endoplasmic reticulum. The cuticular waxes on young leaves and isolated leaf trichomes of ksc16 loss-of-function mutants were depleted of C 35 and C 37 alkanes and alkenes, whereas expression of Arabidopsis KCS16 in yeast and ectopic overexpression in Arabidopsis resulted in accumulation of C 36 and C 38 fatty acid products. Taken together, our results show that KCS16 is the sole enzyme catalysing the elongation of C 34 to C 38 acyl-CoAs in Arabidopsis leaf trichomes and that it contributes to the formation of extra-long compounds in adjacent pavement cells. © 2017 John Wiley & Sons Ltd.

  5. Effects of leaf area index on the coupling between water table, land surface energy fluxes, and planetary boundary layer at the regional scale

    Science.gov (United States)

    Lu, Y.; Rihani, J.; Langensiepen, M.; Simmer, C.

    2013-12-01

    Vegetation plays an important role in the exchange of moisture and energy at the land surface. Previous studies indicate that vegetation increases the complexity of the feedbacks between the atmosphere and subsurface through processes such as interception, root water uptake, leaf surface evaporation, and transpiration. Vegetation cover can affect not only the interaction between water table depth and energy fluxes, but also the development of the planetary boundary layer. Leaf Area Index (LAI) is shown to be a major factor influencing these interactions. In this work, we investigate the sensitivity of water table, surface energy fluxes, and atmospheric boundary layer interactions to LAI as a model input. We particularly focus on the role LAI plays on the location and extent of transition zones of strongest coupling and how this role changes over seasonal timescales for a real catchment. The Terrestrial System Modelling Platform (TerrSysMP), developed within the Transregional Collaborative Research Centre 32 (TR32), is used in this study. TerrSysMP consists of the variably saturated groundwater model ParFlow, the land surface model Community Land Model (CLM), and the regional climate and weather forecast model COSMO (COnsortium for Small-scale Modeling). The sensitivity analysis is performed over a range of LAI values for different vegetation types as extracted from the Moderate Resolution Imaging Spectroradiometer (MODIS) dataset for the Rur catchment in Germany. In the first part of this work, effects of vegetation structure on land surface energy fluxes and their connection to water table dynamics are studied using the stand-alone CLM and the coupled subsurface-surface components of TerrSysMP (ParFlow-CLM), respectively. The interconnection between LAI and transition zones of strongest coupling are investigated and analyzed through a subsequent set of subsurface-surface-atmosphere coupled simulations implementing the full TerrSysMP model system.

  6. LEAF MICROMORPHOMETRY OF Schinus molle L. (ANARCADIACEAE IN DIFFERENT CANOPY HEIGHTS.

    Directory of Open Access Journals (Sweden)

    Marinês Ferreira Pires

    2015-03-01

    Full Text Available Leaf characterization of trees is essential for its identification and use, as well as to understand its relationships with environment. The objective of this work is to study the leaflet anatomy and leaf biometrical characteristics at different canopy heights of Schinus molle plants as a function of its environmental and physiological modifications. Leaves were collected at three different canopy heights: base, middle and upper canopy in a plantation of S. molle. Leaves were used for anatomical and biometrical analysis. For the anatomical analysis, leaves were fixed in FAA and stored in ethanol 70% and further submitted to transversal and paradermical sections. Slides were photomicrographed and image analysis was performed in UTHSCSA-Imagetool. For biometrical analysis leaf area, length, width, dry mass and specific leaf area were evaluated. The leaflets exhibited single layer epidermis, anomocytic and ciclocytic stomata, isobilateral mesophyll, subepidermal parenchyma layer in both adaxial and abaxial faces of epidermis, secretory vessels and lamellar collenchyma in midrib and leaf border. Leaf anatomy modifications occurred in cuticle and mesophyll thickness, vascular system, phloem thickness, and stomatal density in accordance with leaf canopy position. Leaves were smaller and with reduced leaf area at higher canopy positions. S. molle leaf anatomy is different from other species within Schinus genre with modifications under different environmental and physiological modifications promoted by its canopy height.

  7. Variations in the dorso-ventral organization of leaf structure and Kranz anatomy coordinate the control of photosynthesis and associated signalling at the whole leaf level in monocotyledonous species.

    Science.gov (United States)

    Soares-Cordeiro, Ana Sofia; Driscoll, Simon P; Pellny, Till K; Olmos, Enrique; Arrabaça, Maria Celeste; Foyer, Christine H

    2009-12-01

    Photosynthesis and associated signalling are influenced by the dorso-ventral properties of leaves. The degree of adaxial/abaxial symmetry in stomatal numbers, photosynthetic regulation with respect to light orientation and the total section areas of the bundle sheath (BS) cells and the surrounding mesophyll (M) cells on the adaxial and abaxial sides of the vascular bundles were compared in two C(4)[Zea mays (maize) and Paspalum dilatatum] and one C(3)[Triticum turgidum (Durum wheat)] monocotyledonous species. The C(3) leaves had a higher degree of dorso-ventral symmetry than the C(4) leaves. Photosynthetic regulation was the same on each side of the wheat leaves, as were stomatal numbers and the section area of the BS relative to that of the M cells (BS/M section area ratio). In contrast, photosynthetic regulation in maize and P. dilatatum leaves showed a marked surface-specific response to light orientation. Compared to the adaxial sides of the C(4) monocotyledonous leaves, the abaxial surfaces had more stomata and the BS/M section area ratio was significantly higher. Differences in dorso-ventral structure, particularly in Kranz anatomy, serve not only to maximize photosynthetic capacity with respect light orientation in C(4) monocotyledonous leaves but also allow adaxial and abaxial-specific signalling from the respective M cells.

  8. The foliar trichomes of Hypoestes aristata (Vahl) Sol. ex Roem. & Schult var aristata (Acanthaceae) a widespread medicinal plant species in tropical sub-Saharan Africa: with comments on its possible phylogenetic significance.

    Science.gov (United States)

    Bhatt, A; Naidoo, Y; Nicholas, A

    2010-01-01

    The micromorphology of foliar trichomes of Hypoestes aristata var. aristata was studied using stereo, light and scanning microscopy (SEM). This genus belongs to the advanced angiosperm family Acanthaceae, for which few micromorphological leaf studies exist. Results revealed both glandular and non-glandular trichomes, the latter being more abundant on leaf veins, particularly on the abaxial surface of very young leaves. With leaf maturity, the density of non-glandular trichomes decreased. Glandular trichomes were rare and of two types: long-stalked capitate and globose-like peltate trichomes. Capitate trichomes were observed only on the abaxial leaf surface, while peltate trichomes were distributed on both adaxial and abaxial leaf surfaces.

  9. Anatomia foliar de soja infectada por Phakopsora pachyrhizi H. Sydow & Sydow e tratadas com extratos vegetais Leaf anatomy of soybean infected with Phakopsora pachyrhizi H. Sydow & Sydow and treated with plant extracts

    Directory of Open Access Journals (Sweden)

    R.M. Mussury

    2012-01-01

    Full Text Available Folhas de Glycine max (L. Merril,infectadas pelo fungo Phakopsora pachyrhizi H. Sydow & Sydow e tratadas com extratos vegetais foram avaliadas, visando determinar in vivo as modificações anatômicas nas diferentes estruturas/tecidos foliares, além de reconhecer prováveis mecanismos de defesa. Folhas de soja cultivar 181 provenientes do quinto nó foram inoculadas com fungo e tratadas com diferentes extratos vegetais, água e álcool 70%. Para comparação foram analisadas a anatomia das folhas sadia e infectada e realizadas medidas nas estruturas/tecidos foliares. Na folha infectada, observou-se destruição da epiderme e parênquima lacunoso, visível proliferação de tricomas e cutícula espessada, principalmente na face abaxial. Observou-se a presença de compostos fenólicos nas células da epiderme quando rompida, em função do crescimento micelial. Nas folhas infectadas e tratadas com os extratos vegetais de Azadirachta indica, Maytenus ilicifolia e Allium sativum, as estruturas/tecidos vegetais apresentaram aumento de espessura por alongamento celular.Glycine max (L. Merril leaves, infected by the fungus Phakopsora pachyrhizi H. Sydow & Sydow and treated with plant extracts, were evaluated with the aim of determining in vivo the anatomical modifications in different leaf structures and of identifying probable defense mechanisms. Leaves from the 181 soybean cultivar originated from the fifth node were inoculated with the fungus and treated with different plant extracts, water and alcohol at 70%. For comparison, the anatomy of the healthy and infected leaves was analyzed and the leaf structures were measured. In the infected leaf, there was destruction of the epidermis and lacunar parenchyma, apparent trichome proliferation and denser cuticle, especially on the abaxial surface. There were also phenolic compounds in ruptured epidermis cells, due to mycelium growth. In the infected leaves treated with Azadirachta indica, Maytenus

  10. Anatomia foliar como subsídio à taxonomia de espécies do Complexo Briza L. (Poaceae: Pooideae: Poeae Leaf anatomy as a taxonomic tool for Briza Complex species (Poaceae: Pooideae: Poeae

    Directory of Open Access Journals (Sweden)

    Carla Maria Garlet de Pelegrin

    2009-09-01

    Full Text Available O objetivo deste trabalho foi verificar a importância da anatomia foliar, visando a fornecer subsídios para a taxonomia do Complexo Briza, cuja circunscrição vem sendo objeto de discussão. Porções medianas da segunda folha abaixo da inflorescência de 21 táxons do Complexo Briza e um de Erianthecium Parodi foram coletadas, fixadas e processadas de acordo com a metodologia usual em microscopia óptica. Todas as espécies estudadas apresentam padrão anatômico festucóide, característico de gramíneas C3. Os resultados mostram que os caracteres da face abaxial da epiderme relativos à presença/ausência de células suberosas e à forma dos corpos silicosos são úteis para compreender as relações taxonômicas no Complexo Briza, distinguindo as espécies eurasiáticas das americanas. Da mesma forma, alguns caracteres da secção transversal da lâmina foliar como forma da lâmina, quantidade de esclerênquima e estrutura do mesofilo. Por outro lado, com relação às espécies americanas do Complexo Briza, os três agrupamentos aqui obtidos não correspondem a nenhuma proposta anterior de categorias taxonômicas genéricas ou infragenéricas.The aim of this study was to analyze leaf anatomy of selected taxa of the Briza Complex and also of a related genus, Erianthecium Parodi, to provide data for the taxonomy of the Complex, whose circumscription is being discussed. Middle portions of the second leaf below the inflorescence of 21 taxa of the Briza Complex and of Erianthecium bulbosum were collected, fixed and processed according to conventional methodology for light microscopy. All species present anatomical patterns typical of festucoid and C3 grasses. The results suggest that the characters of the abaxial surface of the epidermis such as presence/absence of cork cells and shape of silica bodies are useful for understanding the taxonomic relationships within the Briza Complex, distinguishing Eurasiatic species from American species

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

    Science.gov (United States)

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

    2016-04-01

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

  12. Leaf gas exchange and water status responses of a native and non-native grass to precipitation across contrasting soil surfaces in the Sonoran Desert.

    Science.gov (United States)

    Ignace, Danielle D; Huxman, Travis E; Weltzin, Jake F; Williams, David G

    2007-06-01

    Arid and semi-arid ecosystems of the southwestern US are undergoing changes in vegetation composition and are predicted to experience shifts in climate. To understand implications of these current and predicted changes, we conducted a precipitation manipulation experiment on the Santa Rita Experimental Range in southeastern Arizona. The objectives of our study were to determine how soil surface and seasonal timing of rainfall events mediate the dynamics of leaf-level photosynthesis and plant water status of a native and non-native grass species in response to precipitation pulse events. We followed a simulated precipitation event (pulse) that occurred prior to the onset of the North American monsoon (in June) and at the peak of the monsoon (in August) for 2002 and 2003. We measured responses of pre-dawn water potential, photosynthetic rate, and stomatal conductance of native (Heteropogon contortus) and non-native (Eragrostis lehmanniana) C(4) bunchgrasses on sandy and clay-rich soil surfaces. Soil surface did not always amplify differences in plant response to a pulse event. A June pulse event lead to an increase in plant water status and photosynthesis. Whereas the August pulse did not lead to an increase in plant water status and photosynthesis, due to favorable soil moisture conditions facilitating high plant performance during this period. E. lehmanniana did not demonstrate heightened photosynthetic performance over the native species in response to pulses across both soil surfaces. Overall accumulated leaf-level CO(2) response to a pulse event was dependent on antecedent soil moisture during the August pulse event, but not during the June pulse event. This work highlights the need to understand how desert species respond to pulse events across contrasting soil surfaces in water-limited systems that are predicted to experience changes in climate.

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

    Directory of Open Access Journals (Sweden)

    A. L. Barbu

    2011-07-01

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

  14. Overexpression of the TaSHN1 transcription factor in bread wheat leads to leaf surface modifications, improved drought tolerance and no yield penalty under controlled growth conditions.

    Science.gov (United States)

    Bi, Huihui; Shi, Jianxin; Kovalchuk, Natalia; Luang, Sukanya; Bazanova, Natalia; Chirkova, Larissa; Zhang, Dabing; Shavrukov, Yuri; Stepanenko, Anton; Tricker, Penny; Langridge, Peter; Hrmova, Maria; Lopato, Sergiy; Borisjuk, Nikolai

    2018-05-14

    Transcription factors regulate multiple networks, mediating the responses of organisms to stresses, including drought. Here we investigated the role of the wheat transcription factor TaSHN1 in crop growth and drought tolerance. TaSHN1, isolated from bread wheat, was characterised for molecular interactions and functionality. The overexpression of TaSHN1 in wheat was followed by the evaluation of T 2 and T 3 transgenic lines for drought tolerance, growth and yield components. Leaf surface changes were analysed by light microscopy, SEM, TEM and GC-MS/GC-FID. TaSHN1 behaves as a transcriptional activator in a yeast transactivation assay and binds stress-related DNA cis-elements, determinants of which were revealed using 3D molecular modelling. The overexpression of TaSHN1 in transgenic wheat did not result in a yield penalty under the controlled plant growth conditions of a glasshouse. Transgenic lines had significantly lower stomatal density and leaf water loss, and exhibited improved recovery after severe drought, compared to control plants. The comparative analysis of cuticular waxes revealed an increased accumulation of alkanes in leaves of transgenic lines. Our data demonstrate that TaSHN1 may operate as a positive modulator of drought stress tolerance. Positive attributes could be mediated through an enhanced accumulation of alkanes and reduced stomatal density. This article is protected by copyright. All rights reserved.

  15. Are trichomes involved in the biomechanical systems of Cucurbita leaf petioles?

    Science.gov (United States)

    Zajączkowska, Urszula; Kucharski, Stanisław; Guzek, Dominika

    2015-12-01

    Trichomes are involved in petiole movement and likely function as a part of the plant biomechanical system serving as an additional reservoir of hydrostatic pressure. The large, non-glandular trichomes on Cucurbita petioles occur across collenchyma strands. Time-lapse imaging was used to study the leaf reorientation of Cucurbita maxima 'Bambino' plants placed in horizontal position. The experiment comprised four variants of the large non-glandular petiole trichomes: (1) intact, (2) mechanically removed, (3) dehydrated, and (4) intact but with longitudinally injured petioles. Isolated strands of collenchyma with intact epidermis or epidermis mechanically removed from the abaxial and adaxial sides of the petiole were subjected to breaking test. The stiffness of the non-isolated tissue with intact epidermis was measured using the micro-indentation method. Petioles without trichomes did not exhibit tropic response, and the dehydration of trichomes slowed and prevented complete leaf reorientation. Isolated strands of collenchyma showed no correlation between strength values and position on the petiole. However, strands of collenchyma with epidermis exhibited a significantly greater strength regardless of their position on the petiole. The indentation test showed that non-isolated collenchyma is stiffer on the abaxial side of the petiole. Trichomes from the abaxial side of the petiole were larger at their base. The application of the 'tensile triangles method' revealed that these trichomes had a biomechanically optimized shape in comparison to the adaxial side. We conclude that trichomes can be involved in plant biomechanical system and serve as an additional reservoir of hydrostatic pressure that is necessary for maintaining petioles in the prestressed state.

  16. Leaf Trichomes Morphology of Hyptis suaveolens (L.) Poit. (LAMIACEAE)

    Science.gov (United States)

    Chatri, M.; Baktiar, A.; Mansyurdin, M.; Periadnadi, P.

    2018-04-01

    Hyptis suaveolens L. Poit is one of the plants from family Lamiaceae and is an aromatic plant. The aroma contained in plants is usually secreted by certain structures in plants, such as glandular trichomes. At this plant has been carried out observations about the type and distribution of trichomes by using light microscopy and SEM (Scanning Electron Microscopy). The results showed that the leaves of this plant are non-glandular trichomes types and glandular, either on the surface abaxial and adaxial and on the veins. Non-glandular trichomes consist of the monoselular and multicellular trichomes. While the glandular trichomes consist of peltate type, capitate type I and type II.

  17. 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

    Radiation per day (Rn). The best relationship results when stomatal side surface area is considered. Cladophylls have stomata on all sides while flat leaves have stomata on the abaxial side only. The correction multiplies LAI by .5 in flat leaf vegetation and 1 in T. chinensis vegetation. That means that transpiration rates are two times greater in T. chinensis sites compared with P. deltoides for the same leaf area. The resulting equations are put into a model to quantify ET for each available image and then for the entire growing season.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-11-25

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

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

    KAUST Repository

    Houborg, Rasmus; Cescatti, Alessandro; Gitelson, Anatoly A.

    2013-01-01

    variability exists. Satellite remote sensing can support modeling efforts by offering distributed information on important land surface characteristics, which would be very difficult to obtain otherwise. This study investigates the utility of satellite based

  20. Bioinspired Surface for Low Drag, Self-Cleaning, and Antifouling: Shark Skin, Butterfly and Rice Leaf Effects

    Science.gov (United States)

    Bixler, Gregroy D.

    In this thesis, first presented is an overview of inorganic-fouling and biofouling which is generally undesirable for many medical, marine, and industrial applications. A survey of nature's flora and fauna are studied in order to discover new antifouling methods that could be mimicked for engineering applications. New antifouling methods will presumably incorporate a combination of physical and chemical controls. Presented are mechanisms and experimental results focusing on laminar and turbulent drag reducing shark skin inspired riblet surfaces. This includes new laser etched and riblet film samples for closed channel drag using water, oil, and air as well as in wind tunnel. Also presented are mechanisms and experimental results focusing on the newly discovered rice and butterfly wing effect surfaces. Morphology, drag, self-cleaning, contact angle, and contact angle hysteresis data are presented to understand the role of sample geometrical dimensions, wettability, viscosity, and velocity. Hierarchical liquid repellent coatings combining nano- and micro-sized features and particles are utilized to recreate or combine various effects. Such surfaces have been fabricated with photolithography, soft lithography, hot embossing, and coating techniques. Discussion is provided along with new conceptual models describing the role of surface structures related to low drag, self-cleaning, and antifouling properties. Modeling provides design guidance when developing novel low drag and self-cleaning surfaces for medical, marine, and industrial applications.

  1. Leaf glands of Banisteriopsis muricata (Malpighiaceae: distribution, secretion composition, anatomy and relationship to visitors

    Directory of Open Access Journals (Sweden)

    Lays Araújo Nery

    Full Text Available ABSTRACT Leaf glands are common structures in Malpighiaceae and exhibit great morphological diversity, yet information on their anatomy, secretion and type of visitors remains scarce. The aim of this study was to describe the distribution, anatomical development and chemical and functional properties of leaf glands of Banisteriopsis muricata (Malpighiaceae. Leaves at different stages of development were collected and processed according to standard techniques for light and scanning electron microscopy. Secretion composition was determined by histochemical tests and test-strips, while gland funciton was determined by field observation of interactions with visitors. Leaf glands were located on the petiole and on the abaxial base of the leaf blade. The gland secretion was found to be a protein-rich nectar that was foraged upon by ants ( Solenopsis; it was found accumulated in subcuticular spaces without pores or stomata for its release. Leaf glands were found to develop from protoderm and ground meristem, and consisted of typical secretory epidermis, nectariferous parenchyma and vascularized subnectariferous parenchyma. Therefore, it can be concluded that the distribution, chemical nature of secretion and anatomy of leaf glands of B. muricata characterize them as EFNs, while foraging by ants indicate a mutualistic relationship that possibly protects the plant against herbivores.

  2. Cracking the omega code: hydraulic architecture of the cycad leaf axis.

    Science.gov (United States)

    Tomlinson, P Barry; Ricciardi, Alison; Huggett, Brett A

    2018-03-05

    The leaf axis of members of the order Cycadales ('cycads') has long been recognized by its configuration of independent vascular bundles that, in transverse section, resemble the Greek letter omega (hence the 'omega pattern'). This provides a useful diagnostic character for the order, especially when applied to paleobotany. The function of this pattern has never been elucidated. Here we provide a three-dimensional analysis and explain the pattern in terms of the hydraulic architecture of the pinnately compound cycad leaf. The genus Cycas was used as a simple model, because each leaflet is supplied by a single vascular bundle. Sequential sectioning was conducted throughout the leaf axis and photographed with a digital camera. Photographs were registered and converted to a cinematic format, which provided an objective method of analysis. The omega pattern in the petiole can be sub-divided into three vascular components, an abaxial 'circle', a central 'column' and two adaxial 'wings', the last being the only direct source of vascular supply to the leaflets. Each leaflet is supplied by a vascular bundle that has divided or migrated directly from the closest wing bundle. There is neither multiplication nor anastomoses of vascular bundles in the other two components. Thus, as one proceeds from base to apex along the leaf axis, the number of vascular bundles in circle and column components is reduced distally by their uniform migration throughout all components. Consequently, the distal leaflets are irrigated by the more abaxial bundles, guaranteeing uniform water supply along the length of the axis. The omega pattern exemplifies one of the many solutions plants have achieved in supplying distal appendages of an axis with a uniform water supply. Our method presents a model that can be applied to other genera of cycads with more complex vascular organization. © The Author(s) 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights

  3. Aerial electrostatic spray deposition and canopy penetration in cotton

    Science.gov (United States)

    Spray deposition on abaxial and adaxial leaf surfaces along with canopy penetration are essential for insect control and foliage defoliation in cotton production agriculture. Researchers have reported that electrostatically charged sprays have increased spray deposit onto these surfaces under widel...

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

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    Molero, Julià

    1992-12-01

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

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

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    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

  6. Leaf and inflorescence axis anatomy of Brazilian species of Rapateoideae (Rapateaceae, Poales

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    Ângela L. Daltin

    2015-03-01

    Full Text Available The anatomy of leaves and inflorescence axes of Spathanthus (2 spp., Rapatea (2 spp., Cephalostemon(1 sp., and Duckea(1 sp. (Rapateoideae, Rapateaceae was studied to identify useful characters for taxonomy. The cross-section shape of inflorescence axis differentiates the genera, while the cross-section shape and structure of leaf midrib has a specific value. The following characteristics are exclusive of Spathanthus: silica cells randomly distributed in the leaf epidermis; plicate chlorenchyma in the leaf blade; presence of fiber bundles in the mesophyll and in the inflorescence axis parenchyma. Spathanthus is also distinguished by the number, type and distribution of vascular bundles in the inflorescence axis. The genus Rapatea is characterized by the presence of stomata and silica cells only on the abaxial epidermis of the leaves and chlorenchyma composed of arm cells in the leaf blade. Characteristics with diagnostic value for Cephalostemon riedelianusare: leaf epidermal cells with straight to slightly sinuous walls in frontal view, inflorescence axes presenting a defined cortex, fiber bundles facing the larger vascular bundles and a fistulous pith. The anatomical characteristics of the leaves and inflorescence axes thus proved to be of taxonomic value in generic and specific levels. They are also useful to differentiate Rapateoideae from other subfamilies of Rapateaceae.

  7. MORPHOANATOMICAL LEAF ANALYSIS IN HORTICULTURAL GROUPS OF AVOCADO (Persea americana PLACED AT INIA-CENIAP’S COLLECTION, VENEZUELA

    Directory of Open Access Journals (Sweden)

    H. Ferrer Pereira

    2017-08-01

    Full Text Available The avocado (Persea americana Mill. is the most important species of Lauraceae in America due to its exploitation as food for pre-Columbian and modern cultures. It is a very important seasonal crop in Venezuela based on a perennial fruit tree management. From a selection of 76 accessions (45 cultivars of avocados cultivated at the Germplasm Bank of INIA-CENIAP, a morphoanatomical analysis was performed to identify attributes of taxonomic resolution (diagnostic characters which allow to characterize sets and / or culta. Morphological study was carried out from each accession herborized sample. Information was obtained by freehand transverse leaf sections (epidermis, mesophyll and midvein as well as paradermic preparations, and observed data was recorded in DELTA System. New morphoanatomical characters and discriminating attributes between cultivars were identified and described, especially to discriminate the Mexican group, and a close relationship within West Indian and Guatemalan cultivars was observed due to the variability identified from the latter group. Indument- related attributes were highly informative to discriminate among cultivars, along with the outline, apical angle and projections at the base of the leaf blades, stem cross section and presence of anise odor, progress and joining of the secondary nerve branches, tertiary venation pattern, abaxial contour and thickness of the sclerenchymatous sheath and compaction of the phloem in the vascular bundle, adaxial contour of the median nerve, and thickness, outline and uniformity of the anticlinal walls of adaxial and abaxial epidermal cells.

  8. Laboratory blood analysis in Strigiformes-Part II: plasma biochemistry reference intervals and agreement between the Abaxis Vetscan V2 and the Roche Cobas c501.

    Science.gov (United States)

    Ammersbach, Mélanie; Beaufrère, Hugues; Gionet Rollick, Annick; Tully, Thomas

    2015-03-01

    Limited plasma biochemical information is available in Strigiformes. Only one study investigated the agreement between a point-of-care with a reference laboratory analyzer for biochemistry variables in birds. The objective was to report reference intervals (RI) for plasma biochemistry variables in Strigiformes, and to assess agreement between the Abaxis Vetscan V2 and Roche Cobas c501. A prospective study was designed to assess plasma biochemistry RI for concentration of calcium, phosphorus, total protein, albumin, globulin, glucose, bilirubin, uric acid, bile acids, sodium, potassium, and chloride, and activities of AST, GGT, CK, amylase, lipase, LDH, and GLDH. In addition, the agreement between the Vetscan and the Cobas in owl species was assessed. A total of 190 individuals were sampled belonging to 12 Strigiformes species including Barn Owls, Barred Owls, Great Horned Owls, Eurasian Eagle Owls, Spectacled Owls, Eastern Screech Owls, Long-Eared Owls, Short-Eared Owls, Great Gray Owls, Snowy Owls, Northern Saw-Whet Owls, and Northern Hawk-Owls. Order-, species-, and method-specific RI were determined on both analyzers. Although Vetscan data were not equivalent to the Cobas, 4 analytes (glucose, AST, CK, and total protein, with correction for bias) were within acceptable agreement, 3 analytes (uric acid, calcium, and phosphorus) were within close agreement, and the remaining analytes were in strong disagreement. Species-specific differences were observed notably for the concentration of glucose in Barn Owls and electrolytes in Northern Saw-Whet Owls. Overall, this study suggests that the Vetscan has acceptable clinical performance in Strigiformes for some analytes and highlights discrepancies for several analytes. © 2015 American Society for Veterinary Clinical Pathology.

  9. Caracterização anatômica de folha, colmo e rizoma de Digitaria insularis Anatomical characterization of the leaf, stem and rhizome of Digitaria insularis

    Directory of Open Access Journals (Sweden)

    A.F.L. Machado

    2008-03-01

    reached the preflowering stage, three totally expanded leaves were collected per plant, between the third and fifth nodes. Fragments of the internodes covered by the sheaths of the sampled leaves were collected together with the rhizomes. The samples were fixed in FAA50 and embedded in ethanol to obtain histological sections and mount the slider, according to the methodology. Leaf samples were diaphanized, following the usual methodology, to obtain the stomatal index and stomatal density at the epidermal surfaces. Plants derived from rhizomes had higher stomatal index and larger number of stomata per mm², thicker adaxial and abaxial epidermis faces and thicker leaf lamina. The intense coloration in the rhizomes treated with lugol indicated the presence of a great amount of starch, regardless of the origin of the material.

  10. Leaf anatomy of the South African Danthonieae (Poaceae. III. Merxmuellera stricta

    Directory of Open Access Journals (Sweden)

    R. P. Ellis

    1980-11-01

    Full Text Available The anatomical structure, of the leaf blade as seen in transverse section, and of the abaxial epidermis, of Merxmuellera stricta (Schrad. Conert is described and illustrated. In this variable species four distinct anatomical “forms” are recognized viz. the typical  M. stricta form, the Cathedral Peak form, the Drakensberg form and the alpine form. The alpine and Cathedral Peak forms have recently been described as M. guillarmodiae Conert (1975. The degree of anatomical differentiation of these “forms” resembles the situation described in M. disticha (Nees Conert (Ellis, 1980. Populations of both M. stricta and M. disticha from the Drakensberg mountains display extensive anatomical diversification which appears to be correlated with environmental factors. In addition, morphological differences are exhibited as well and the anatomical “forms” of M. stricta probably warrant taxonomic recognition.

  11. Biophysical control of leaf temperature

    Science.gov (United States)

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

    2014-12-01

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

  12. MULTIVARIATE ANALYSIS OF BALI SALAK CULTIVARS (SALACCA ZALACCA VAR. AMBOINENSIS (BECC. MOGEA BASED ON LEAF MICROMORPHOLOGICAL CHARACTERS

    Directory of Open Access Journals (Sweden)

    NI MADE GARI

    2011-06-01

    Full Text Available Leaf micromorphology of 13 Bali salak cultivars was studied by using multivariate analysis (Principal component analysis. The results showed that the cultivars clustered into a main group consisted of nine cultivars (Boni, Bingin, Selem, Embad, Nangka, Penyalin, Maong, Nyuh, and Putih. However, two cultivars (Muani and Gondok were distinctly separated from this main group and two the others Nanas and Gula were intermediate. The principal component analysis (PCA revealed that the main group has highly correlated to the characters abaxial cell length and number of cross vein density. Muani cultivar generally had longer adaxial cells, wider guard cells and lower stomatal index than the other cultivars. These three characters strongly influenced the separation of Muani from the others. Similarly, Gondok cultivar generally had wider abaxial cells than the other cultivars that discriminated Gondok clearly from the others. Whereas, the intermediate cultivars (Gula and Nanas were placed between the main group that consisted of nine cultivars and the two separated cultivars (Muani and Gondok. These cultivars (Gula and Nanas had intermediate values, which influenced their separations.

  13. Is the lotus leaf superhydrophobic?

    Science.gov (United States)

    Cheng, Yang-Tse; Rodak, Daniel E.

    2005-04-01

    Superhydrophobic surfaces have important technical applications ranging from self-cleaning window glasses, paints, and fabrics to low-friction surfaces. The archetype superhydrophobic surface is that of the lotus leaf. When rain falls on lotus leaves, water beads up with a contact angle in the superhydrophobic range of about 160°. The water drops promptly roll off the leaves collecting dirt along the way. This lotus effect has, in recent years, stimulated much research effort worldwide in the fabrication of surfaces with superhydrophobicity. But, is the lotus surface truly superhydrophobic? This work shows that the lotus leaves can be either hydrophobic or hydrophilic, depending on how the water gets on to their surfaces. This finding has significant ramifications on how to make and use superhydrophobic surfaces.

  14. Betel leaf in stoma care.

    Science.gov (United States)

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

    2007-07-01

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

  15. Leaf structural adaptations of two Limonium miller (Plumbaginales, Plumbaginaceae taxa

    Directory of Open Access Journals (Sweden)

    Zorić Lana N.

    2013-01-01

    Full Text Available Limonium gmelinii (Willd. O. Kuntze 1891 subsp. hungaricum (Klokov Soó is Pannonian endemic subspecies that inhabits continental halobiomes, while Limonium anfractum (Salmon Salmon 1924 is one of the indicators of halophyte vegetation of marine rocks and its distribution is restricted to the southern parts of Mediterranean Sea coast. In this work, micromorphological and anatomical characters of leaves of these two Limonium taxa were analyzed, in order to examine their adaptations to specific environmental conditions on saline habitats. The results showed that both taxa exhibited strong xeromorphic adaptations that reflected in flat cell walls of epidermal cells, thick cuticle, high palisade/spongy tissue ratio, high index of palisade cells, the presence of sclereid idioblasts in leaf mesophyll and mechanical tissue by phloem and xylem. Both taxa are crynohalophytes and have salt glands on adaxial and abaxial epidermis for excretion of surplus salt. Relatively high dimensions of mesophyll cells, absence of non-glandular hairs and unprotected stomata slightly increased above the level of epidermal cells, are also adaptations to increased salinity. [Projekat Ministarstva nauke Republike Srbije, br. 173002

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

    Science.gov (United States)

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

    2016-07-01

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

  17. Leaf anatomy of the genus Ehrharta (Poaceae in southern Africa: the Setacea group

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    R. P. Ellis

    1987-10-01

    Full Text Available The leaf blade anatomy of the taxa of the Setacea group of species of the genus Ehrharta is described and illustrated. This group includes E. rupestris Nees ex Trin. subsp.  rupestris, subsp.  tricostata (Stapf Gibbs Russell and subsp.  dodii (Stapf Gibbs Russell, as well as E. setacea Nees subsp.  setacea, subsp.  scabra (Stapf Gibbs Russell, subsp.  uniflora (Burch, ex Stapf Gibbs Russell and subsp.  disticha Gibbs Russell. All these taxa share a very characteristic leaf anatomy with inrolled or infolded leaves without keels and have adaxial ribs with interlocking prickles. The chlorenchyma is dense and compact with inwardly projecting invaginations visible in all taxa except  E. setacea subsp.  setacea. In E .  setacea subsp. scabra typical arm cells are present. Abaxial costal and intercostal zones are not differentiated and stomata are absent. The long cells are hexagonal or inflated with sinuous walls. Silica bodies are single or paired and rounded in shape. Small hook-like prickles with short barbs are common. Microhairs with a short, truncated distal cell occur. This leaf anatomical structure differs considerably from that of the other species groups recognized in African  Ehrharta and the Setacea group appears to be more distinct from the other groups than they are from each other.

  18. Cladodes, leaf-like organs in Asparagus, show the significance of co-option of pre-existing genetic regulatory circuit for morphological diversity of plants.

    Science.gov (United States)

    Nakayama, Hokuto; Yamaguchi, Takahiro; Tsukaya, Hirokazu

    2012-08-01

    Plants in the genus Asparagus have determinate leaf-like organs called cladodes in the position of leaf axils. Because of their leaf-like morphology, axillary position, and morphological variation, it has been unclear how this unusual organ has evolved and diversified. In the previous study, we have shown that cladodes in the genus Asparagus are modified axillary shoots and proposed a model that cladodes have arisen by co-option and deployment of genetic regulatory circuit (GRC) involved in leaf development. Moreover, we proposed that the alteration of the expression pattern of genes involved in establishment of adaxial/abaxial polarity has led to the morphological diversification from leaf-like to rod-like form of cladodes in the genus. Thus, these results indicated that the co-option and alteration of pre-existing GRC play an important role in acquisition and subsequent morphological diversification. Here, we present data of further expression analysis of A. asparagoides. The results suggested that only a part of the GRC involved in leaf development appears to have been co-opted into cladode development. Based on our study and several examples of the morphological diversification, we briefly discuss the importance of co-option of pre-existing GRC and its genetic modularity in the morphological diversity of plants during evolution.

  19. An in vitro biomechanical comparison of equine proximal interphalangeal joint arthrodesis techniques: an axial positioned dynamic compression plate and two abaxial transarticular cortical screws inserted in lag fashion versus three parallel transarticular cortical screws inserted in lag fashion.

    Science.gov (United States)

    Sod, Gary A; Riggs, Laura M; Mitchell, Colin F; Hubert, Jeremy D; Martin, George S

    2010-01-01

    To compare in vitro monotonic biomechanical properties of an axial 3-hole, 4.5 mm narrow dynamic compression plate (DCP) using 5.5 mm cortical screws in conjunction with 2 abaxial transarticular 5.5 mm cortical screws inserted in lag fashion (DCP-TLS) with 3 parallel transarticular 5.5 mm cortical screws inserted in lag fashion (3-TLS) for the equine proximal interphalangeal (PIP) joint arthrodesis. Paired in vitro biomechanical testing of 2 methods of stabilizing cadaveric adult equine forelimb PIP joints. Cadaveric adult equine forelimbs (n=15 pairs). For each forelimb pair, 1 PIP joint was stabilized with an axial 3-hole narrow DCP (4.5 mm) using 5.5 mm cortical screws in conjunction with 2 abaxial transarticular 5.5 mm cortical screws inserted in lag fashion and 1 with 3 parallel transarticular 5.5 mm cortical screws inserted in lag fashion. Five matching pairs of constructs were tested in single cycle to failure under axial compression, 5 construct pairs were tested for cyclic fatigue under axial compression, and 5 construct pairs were tested in single cycle to failure under torsional loading. Mean values for each fixation method were compared using a paired t-test within each group with statistical significance set at Pcycle to failure, of the DCP-TLS fixation were significantly greater than those of the 3-TLS fixation. Mean cycles to failure in axial compression of the DCP-TLS fixation was significantly greater than that of the 3-TLS fixation. The DCP-TLS was superior to the 3-TLS in resisting the static overload forces and in resisting cyclic fatigue. The results of this in vitro study may provide information to aid in the selection of a treatment modality for arthrodesis of the equine PIP joint.

  20. 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.

  1. Global variability in leaf respiration in relation to climate and leaf traits

    Science.gov (United States)

    Atkin, Owen K.

    2015-04-01

    Leaf respiration plays a vital role in regulating ecosystem functioning and the Earth's climate. Because of this, it is imperative that that Earth-system, climate and ecosystem-level models be able to accurately predict variations in rates of leaf respiration. In the field of photosynthesis research, the F/vC/B model has enabled modellers to accurately predict variations in photosynthesis through time and space. By contrast, we lack an equivalent biochemical model to predict variations in leaf respiration. Consequently, we need to rely on phenomenological approaches to model variations in respiration across the Earth's surface. Such approaches require that we develop a thorough understanding of how rates of respiration vary among species and whether global environmental gradients play a role in determining variations in leaf respiration. Dealing with these issues requires that data sets be assembled on rates of leaf respiration in biomes across the Earth's surface. In this talk, I will use a newly-assembled global database on leaf respiration and associated traits (including photosynthesis) to highlight variation in leaf respiration (and the balance between respiration and photosynthesis) across global gradients in growth temperature and aridity.

  2. Modification and co-option of leaf developmental programs for the acquisition of flat structures in monocots: Unifacial leaves in Juncus and cladodes in Asparagus

    Directory of Open Access Journals (Sweden)

    Hokuto eNakayama

    2013-07-01

    Full Text Available It has been suggested that modification and co-option of existing gene regulatory networks (GRNs play an important role in the morphological diversity. In plants, leaf development is one of active research areas, and the basic GRN for leaf development is beginning to be understood. Moreover, leaves show wide variation in their form, and some of this variation is thought to be the result of adaptation. Thus, leaves and leaf-like organs are an emerging and interesting model to reveal how existing GRNs give rise to novel forms and architectures during evolution. In this review, we highlight recent findings in Evo-Devo studies, especially on Juncus unifacial leaves, which are composed of lamina with abaxialized identities, and Asparagus cladodes, which are leaf-like organs at the axils of scale leaves. Based on these studies, we discuss how flat structures have evolved and morphologically diversified in shoot systems of monocot species, focusing on the modification and co-option of GRN for leaf development.

  3. The foliar trichomes of Hypoestes aristata (Vahl Sol. ex Roem. & Schult var aristata (Acanthaceae a widespread medicinal plant species in tropical sub-Saharan Africa: with comments on its possible phylogenetic significance

    Directory of Open Access Journals (Sweden)

    A Bhatt

    2010-01-01

    Full Text Available The micromorphology of foliar trichomes of Hypoestes aristata var. aristata was studied using stereo, light and scanning microscopy (SEM. This genus belongs to the advanced angiosperm family Acanthaceae, for which few micromorphological leaf studies exist. Results revealed both glandular and non-glandular trichomes, the latter being more abundant on leaf veins, particularly on the abaxial surface of very young leaves. With leaf maturity, the density of non-glandular trichomes decreased. Glandular trichomes were rare and of two types: long-stalked capitate and globose-like peltate trichomes. Capitate trichomes were observed only on the abaxial leaf surface, while peltate trichomes were distributed on both adaxial and abaxial leaf surfaces.

  4. Diferenciação entre Egeria densa e Egeria najas pelos caracteres anatômicos foliares Differentiation between Egeria densa and Egeria najas by leaf anatomic characters

    Directory of Open Access Journals (Sweden)

    R.A. Rodella

    2006-06-01

    ção de caracteres anatômicos quantitativos permitiu auxiliar na diferenciação dos acessos e das espécies estudadas; entretanto, devem ser incrementados os estudos relacionando a estrutura anatômica com a resistência e suscetibilidade aos herbicidas.Seven leaf blade quantitative anatomic characters were used to differentiate five accesses of Egeria densa, and three accesses of Egeria najas, collected in 'Jupiá', 'Salto Grande', 'Três Irmãos', 'Promissão', 'Nova Avanhandava' and 'Ibitinga' reservoirs, in relation to leaf blade descriptive and quantitative anatomic characteristics, in order to obtain a better understanding the relations among these anatomic structures and herbicide penetration and translocation. Another objective was to provide identification of susceptible and resistant accesses to some chemical products. Leaf samples were collected, fixed in FAA 50, infiltrated in glycol metacrylate resin, cut transversally with 8 mm of thickness, and stained with toluidine blue. The following leaf anatomic middle vein characters were quantitatively evaluated (%: adaxial and abaxial epidermis, vascular bundle and parenchyma. In the region between the vein and the leaf margin, the % adaxial and abaxial epidermis and leaf thickness were evaluated. The quantitative anatomic characters of the leaf were submitted to statistic multivariate methods of Cluster Analysis and Principal Components Analysis. Results showed that three groups were formed according to similarity levels: group 1 - three accesses of E. najas; group 2 - four accesses of E. densa; group 3 - one access of E. densa. The anatomic characters with high discriminatory degree were: % vascular bundle and abaxial epidermis of middle vein, and % adaxial and abaxial epidermis of the region between the vein and leaf margin. In conclusion, it was observed that the quantitative anatomic characters were determinant in differentiating accesses and aquatic weed species; however, further studies must be conducted to

  5. Efeitos da radiação ultravioleta-B sobre a morfologia foliar de Arabidopsis thaliana (L. Heynh. (Brassicaceae Effects of ultraviolet-B radiation on leaf morphology of Arabidopsis thaliana (L. Heynh. (Brassicaceae

    Directory of Open Access Journals (Sweden)

    Maria Regina Torres Boeger

    2006-06-01

    Full Text Available A redução da camada de ozônio resulta no aumento da radiação ultravioleta que atinge a superfície terrestre, especialmente a radiação ultravioletaB (UV-B. O aumento da radiação poderá induzir a mudanças estruturais e fisiológicas nas plantas, influenciando no seu crescimento e desenvolvimento. O objetivo deste trabalho foi determinar os efeitos da radiação UV-B ambiente sobre a morfologia das folhas de Arabidopsis thaliana desenvolvidas em condições controladas. As sementes de A. thaliana cresceram em câmaras de crescimento, com 300 µmol m-2s-1 de radiação fotossinteticamente ativa (PAR com ou sem 6 kJ m-2 s-1 de radiação UV-Bbe (UV-Bbe; UV-B biologicamente efetiva. Após 21 dias, 10 folhas de cada tratamento (com e sem radiação UV-B foram coletadas para avaliar área foliar, massa fresca e seca, AEF, densidades estomáticas e de tricomas de ambas as faces da folha, espessura da lâmina foliar e concentração de compostos fenólicos e de clorofila total, a e b. As folhas tratadas com radiação UV-B apresentaram menor área foliar, massa fresca e seca, densidade de tricomas na face adaxial e densidade de estômatos na face abaxial da folha. Entretanto, apresentaram os maiores valores médios de espessura total da lâmina e do mesofilo, maior concentração de clorofila total, clorofila a e clorofila b e compostos fenólicos foliares do que as folhas não tratadas com radiação UV-B. Essas diferenças morfológicas significativas (p Reduction of the ozone layer results in the increase in ultraviolet radiation reaching the earth's surface, especially the ultraviolet-B (UV-B. The increase of radiation may induce structural and physiological changes in plants, influencing their growth and development. This paper evaluates the effects of ambient UV-B radiation upon to the leaf morphology of Arabidopsis thaliana developed under controlled conditions. The seeds of A. thaliana grown in environmental chamber, with 300 µmol m-2

  6. Leaf anatomy of genotypes of banana plant grown under coloured ...

    African Journals Online (AJOL)

    SAM

    2014-06-04

    Jun 4, 2014 ... is oriented toward hypodermis of abaxial face (Sumardi .... Means followed by the same lowercase letter in the column and uppercase letter in the row for each variable do ..... F.A.O. Statistical database: Food and agricultural.

  7. Dorsoventral variations in dark chilling effects on photosynthesis and stomatal function in Paspalum dilatatum leaves.

    Science.gov (United States)

    Soares-Cordeiro, Ana Sofia; Driscoll, Simon P; Arrabaça, Maria Celeste; Foyer, Christine H

    2011-01-01

    The effects of dark chilling on the leaf-side-specific regulation of photosynthesis were characterized in the C(4) grass Paspalum dilatatum. CO(2)- and light-response curves for photosynthesis and associated parameters were measured on whole leaves and on each leaf side independently under adaxial and abaxial illumination before and after plants were exposed to dark chilling for one or two consecutive nights. The stomata closed on the adaxial sides of the leaves under abaxial illumination and no CO(2) uptake could be detected on this surface. However, high rates of whole leaf photosynthesis were still observed because CO(2) assimilation rates were increased on the abaxial sides of the leaves under abaxial illumination. Under adaxial illumination both leaf surfaces contributed to the inhibition of whole leaf photosynthesis observed after one night of chilling. After two nights of chilling photosynthesis remained inhibited on the abaxial side of the leaf but the adaxial side had recovered, an effect related to increased maximal ribulose-1,5-bisphosphate carboxylation rates (V(cmax)) and enhanced maximal electron transport rates (J(max)). Under abaxial illumination, whole leaf photosynthesis was decreased only after the second night of chilling. The chilling-dependent inhibition of photosynthesis was located largely on the abaxial side of the leaf and was related to decreased V(cmax) and J(max), but not to the maximal phosphoenolpyruvate carboxylase carboxylation rate (V(pmax)). Each side of the leaf therefore exhibits a unique sensitivity to stress and recovery. Side-specific responses to stress are related to differences in the control of enzyme and photosynthetic electron transport activities.

  8. Wind increases leaf water use efficiency.

    Science.gov (United States)

    Schymanski, Stanislaus J; Or, Dani

    2016-07-01

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

  9. Response of Eustoma Leaf Phenotype and Photosynthetic Performance to LED Light Quality

    Directory of Open Access Journals (Sweden)

    Md Zohurul Kadir Roni

    2017-10-01

    Full Text Available In a controlled environment, light from light-emitting diodes (LEDs has been associated with affecting the leaf characteristics of Eustoma. LEDs help plant growth and development, yet little is known about photosynthetic performance and related anatomical features in the early growth stage of Eustoma leaves. In this study, we examined the effects of blue (B, red (R, and white (W LEDs on the photosynthetic performance of Eustoma leaves, as well as leaf morphology and anatomy including epidermal layer thickness, palisade cells, and stomatal characteristics. Leaves grown under B LEDs were thicker and had a higher chlorophyll content than those grown under the R and W LEDs. Leaves under B LEDs had greater net photosynthetic rates (A, stomatal conductance (gs, and transpiration rates (E, especially at a higher photon flux density (PPFD, that resulted in a decrease in the intercellular CO2 concentration (Ci, than leaves under the W and R LEDs. B LEDs resulted in greater abaxial epidermal layer thickness and palisade cell length and width than the R and W LED treatments. The palisade cells also developed a more cylindrical shape in response to the B LEDs. B LED leaves also showed greater guard cell length, breadth, and area, and stomatal density, than W or R LEDs, which may contribute to increased A, gs and E at higher PPFDs.

  10. The effectiveness of betel leaf (Piper betle Linn extract gel and cocoa bean (Theobroma cacao L extract gel application against the hardness of enamel surface in vitro.

    Directory of Open Access Journals (Sweden)

    Juni Jekti Nugroho

    2017-04-01

    Full Text Available Objective : Nowadays several ways  have been evolved  to increase the hardness of the enamel surface as an effort to prevent caries. One of the alternatives that can be used is application of gel with herbal basic material. Material and Methods : The use of herbal basic material is preferred by people because the side effects are relatively small compared to synthetic drugs. Piper betle and cocoa beans are medicinal plants that is often used by people to inhibit caries. This is because piper betle and cocoa beans contain hardness that may influence the enamel surface. The purpose of this research was to determine the effect of piper betle extract gel and cocoa bean extract gel against the hardness of enamel surface. The samples, maxillary first premolar teeth, which has been extracted and does not have caries, were divided into 3 treatment groups: piper betle extract gel, cocoa bean extract gel, and distilled water as a negative control. Each treatment group consisted of 8 samples. The samples are decoronated in cemento-enamel junction (CEJ areas and planted on orthoplast blocks with labial surface facing up. Samples were applied in labial enamel surface to 5, 15 and 35 minutes period times. Samples before and after the application in each treatment group were measured using Universal Hardness Tester. Data were collected and analyzed using ANNOVA Repeated test. Results : Showed there were significant differences (p 0.05 of enamel surface hardness before and after the application of piper betel extract gel and distilled water. Conclusion : Therefore it can be concluded that cocoa been extract gel is more effective to increase the hardness of email surface.

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

    Directory of Open Access Journals (Sweden)

    Mykola V. Yatsenko

    2013-04-01

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

  12. Geometric leaf placement strategies

    International Nuclear Information System (INIS)

    Fenwick, J D; Temple, S W P; Clements, R W; Lawrence, G P; Mayles, H M O; Mayles, W P M

    2004-01-01

    Geometric leaf placement strategies for multileaf collimators (MLCs) typically involve the expansion of the beam's-eye-view contour of a target by a uniform MLC margin, followed by movement of the leaves until some point on each leaf end touches the expanded contour. Film-based dose-distribution measurements have been made to determine appropriate MLC margins-characterized through an index d 90 -for multileaves set using one particular strategy to straight lines lying at various angles to the direction of leaf travel. Simple trigonometric relationships exist between different geometric leaf placement strategies and are used to generalize the results of the film work into d 90 values for several different strategies. Measured d 90 values vary both with angle and leaf placement strategy. A model has been derived that explains and describes quite well the observed variations of d 90 with angle. The d 90 angular variations of the strategies studied differ substantially, and geometric and dosimetric reasoning suggests that the best strategy is the one with the least angular variation. Using this criterion, the best straightforwardly implementable strategy studied is a 'touch circle' approach for which semicircles are imagined to be inscribed within leaf ends, the leaves being moved until the semicircles just touch the expanded target outline

  13. Mueller matrix of a dicot leaf

    Science.gov (United States)

    Vanderbilt, Vern C.; Daughtry, Craig S. T.

    2012-06-01

    A better understanding of the information contained in the spectral, polarized bidirectional reflectance and transmittance of leaves may lead to improved techniques for identifying plant species in remotely sensed imagery as well as better estimates of plant moisture and nutritional status. Here we report an investigation of the optical polarizing properties of several leaves of one species, Cannabis sativa, represented by a 3x3 Mueller matrix measured over the wavelength region 400-2,400 nm. Our results support the hypothesis that the leaf surface alters the polarization of incident light - polarizing off nadir, unpolarized incident light, for example - while the leaf volume tends to depolarized incident polarized light.

  14. 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...

  15. 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.

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

    Science.gov (United States)

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

    2016-04-01

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

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

    Science.gov (United States)

    Schrader, Julian; Pillar, Giso; Kreft, Holger

    2017-11-01

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

  18. The epidermis in Passerina/ (Thymelaeaceae: structure, function and taxonomic significance

    Directory of Open Access Journals (Sweden)

    C. L. Bredenkamp

    2000-02-01

    Full Text Available Epidermal features were studied in all 17 species of Passerina, a genus endemic to southern Africa. Leaves in Passerina are inversely ericoid, the adaxial surface concave and the abaxial surface convex. Leaves are inversely dorsiventral and epistomatic. The adaxial epidermis is villous, with unicellular, uniseriate trichomes and relatively small thin-walled cells, promoting flexibility of leaf margins owing to turgor changes. In common with many other Thymelaeaceae, abaxial epidermal cells are large and tanniniferous with mucilaginous cell walls. The cuticle is adaxially thin, but abaxially well devel­oped, probably enabling the leaf to restrict water loss and to tolerate high light intensity and UV-B radiation. Epicuticular waxes, present in all species, comprise both soft and plate waxes. Epidermal structure proves to be taxonomically impor­tant at family, genus and species levels. Interspecific differences include arrangement of stomata and presence or absence of abaxial epidermal hair. Other diagnostic characters of the abaxial epidermal cells are arrangement,size and shape, cutic- ular ornamentation and presence or absence of wax platelets. Two groups of species on the basis of abaxial epidermal cell orientation are recognised. Many leaf epidermal features in Passerina are interpreted as structural adaptations to the Mediterranean climate of the Cape.

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

    Science.gov (United States)

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

    2017-12-01

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

  20. Aerial stem and leaf morphoanatomy of some species of Smilax

    Directory of Open Access Journals (Sweden)

    Aline R. Martins

    2013-06-01

    Full Text Available This study aimed to describe the morphoanatomy of the aerial vegetative organs of seven Smilax species, used in Brazilian folk medicine. Samples of leaves and stems were fixed with FAA 50, embedded in historesin, sectioned on a rotary microtome, stained and mounted in synthetic resin. Cuticle ornamentation was analyzed with standard scanning electron microscopy. In the frontal view, the walls of the adaxial epidermis are straight in S. brasiliensis, S. cissoides, S. goyazana and sinuous in the other species. The walls of the epidermis on the abaxial surface are straight in S. brasiliensis, S. goyazana, S. rufescens, sinuous in S. campestris, S. fluminensis, S. oblongifolia, and wavy in S. cissoides. The stomata are paracytic in S. brasiliensis, S. goyazana, S. oblongifolia, and S. rufescens, anomocytic in S. cissoides, S. campestris; anisocytic and paracytic in S. fluminensis. The midrib has three vascular bundles that are individually wrapped by lignified cells in S. brasiliensis, S. cissoides, and S. fluminensis. In the other, the three vascular bundles are surrounded by a single lignified sheath. In the stems the vascular cylinder is surrounded by a sclerenchymatous ring with the exception of Smilax fluminensis, which has a starch sheath and internal layers of thin-walled cells.

  1. Titan Lifting Entry & Atmospheric Flight (T-LEAF) Science Mission

    Science.gov (United States)

    Lee, G.; Sen, B.; Ross, F.; Sokol, D.

    2016-12-01

    Northrop Grumman has been developing the Titan Lifting Entry & Atmospheric Flight (T-LEAF) sky rover to roam the lower atmosphere and observe at close quarters the lakes and plains of Saturn's ocean moon, Titan. T-LEAF also supports surface exploration and science by providing precision delivery of in-situ instruments to the surface of Titan. T-LEAF is a highly maneuverable sky rover and its aerodynamic shape (i.e., a flying wing) does not restrict it to following prevailing wind patterns on Titan, but allows mission operators to chart its course. This freedom of mobility allows T-LEAF to follow the shorelines of Titan's methane lakes, for example, or to target very specific surface locations. We will present a straw man concept of T-LEAF, including size, mass, power, on-board science payloads and measurement, and surface science dropsonde deployment CONOPS. We will discuss the various science instruments and their vehicle level impacts, such as meteorological and electric field sensors, acoustic sensors for measuring shallow depths, multi-spectral imagers, high definition cameras and surface science dropsondes. The stability of T-LEAF and its long residence time on Titan will provide for time to perform a large aerial survey of select prime surface targets deployment of dropsondes at selected locations surface measurements that are coordinated with on-board remote measurements communication relay capabilities to orbiter (or Earth). In this context, we will specifically focus upon key factors impacting the design and performance of T-LEAF science: science payload accommodation, constraints and opportunities characteristics of flight, payload deployment and measurement CONOPS in the Titan atmosphere. This presentation will show how these factors provide constraints as well as enable opportunities for novel long duration scientific studies of Titan's surface.

  2. Morfoanatomia de folha e caule de Genipa americana L., Rubiaceae Leaf and stem morpho-anatomy of Genipa americana L., Rubiaceae

    Directory of Open Access Journals (Sweden)

    Marianna Erbano

    2010-12-01

    Full Text Available Genipa americana L., conhecida como jenipapo, é uma Rubiaceae nativa do Brasil e as suas folhas são utilizadas pela população como antidiarreico e febrífugo, e o caule como anti-hemorrágico, contra luxações e contusões. Com o objetivo de caracterizar macro e microscopicamente folhas adultas e caules jovens para o controle de qualidade farmacognóstico, essa planta medicinal foi analisada segundo a metodologia clássica de morfoanatomia vegetal. Genipa americana apresenta folhas simples, opostas, de formato obovado a oblanceolado e pecíolos curtos. A epiderme foliar é uniestratificada e revestida por cutícula delgada e levemente estriada. Os estômatos são paracíticos e restritos à superfície abaxial. Há tricomas tectores uni e pluricelulares predominantemente na superfície abaxial. O mesofilo é dorsiventral. Em secção transversal, a nervura central é plano-convexa e o pecíolo é circular, ambos apresentando um feixe vascular colateral em disposição cilíndrica e outros menores. O caule possui felogênio localizado nas camadas subepidérmicas, colênquima anelar e um cilindro floemático externo ao de xilema, sendo ambos percorridos por raios parenquimáticos estreitos. Ocorrem idioblastos contendo compostos fenólicos, areia cristalina e drusas de oxalato de cálcio na folha e no caule.Genipa americana L., known as jenipapo, is a Rubiaceae species native to Brazil. Its leaves are used by the population as anti-diarrheic and febrifuge, and its stem as anti-hemorrhagic and for trauma injuries. Aiming to identify macro and microscopically mature leaves and young stems for the pharmacognostic quality control, this medicinal plant was investigated according to standard morpho-anatomical techniques. The leaves are simple, opposite, obovate-oblanceolate, presenting short petiole. The epidermis is uniseriate and coated with thin and slightly striate cuticle. The stomata are paracytic and restricted to the abaxial surface. It

  3. Stomatal distribution, stomatal density and daily leaf movement in Acacia aroma (Leguminosae Distribución y densidad estomática y movimiento diario de la hoja en Acacia aroma (Leguminosae

    Directory of Open Access Journals (Sweden)

    Marcelo P. Hernández

    2010-12-01

    Full Text Available Acacia aroma Gillies ex Hook. & Arn. grows in the Chacoan and Yungas Biogeographic Provinces, Argentina. It has numerous medicinal applications, sweet and edible fruits, and it may be used as forage. The objective of the present contribution was to analyse the stomatal distribution and stomatal density on the secondary leaflet surfaces, in different parts of the leaf, and at different tree crown levels, establishing the leaf movement and environmental condition relationships. The work was performed with fresh material and herbarium specimens, using conventional anatomical techniques. Stomatal distribution on the secondary leaflet surfaces was established, and differences in stomatal density among basal, medium and apical leaflets were found. A decrease in stomatal density from the lower level to the upper level of the tree crown would be connected with that. The stomatal distribution and density appear related to the secondary leaflet shape and its position on the secondary rachis, interacting with the daily secondary leaflets and leaf movement, and the weather conditions. It is interesting that the medium value of stomata density were found in the middle part of the leaf and at the middle level of the tree crown. Original illustrations are given.Acacia aroma crece en las Provincias Biogeográficas Chaqueña y de las Yungas, Argentina. Este árbol posee numerosas aplicaciones en medicina popular, sus frutos son comestibles y puede ser usada como forraje. Los objetivos de la presente contribución fueron: establecer la distribución y densidad de los estomas en el folíolo secundario, en distintos folíolos secundarios de la misma hoja y en los folíolos secundarios de las hojas de la parte basal, media y superior de la copa del árbol, estableciendo relaciones con el movimiento diario de las hojas y condiciones ambientales. Para el estudio se utilizó material fresco y ejemplares de herbario empleando técnicas de anatomía convencionales. Se

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

    Science.gov (United States)

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

    2014-09-15

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

  5. Comparison of leaf-on and leaf-off ALS data for mapping riparian tree species

    Science.gov (United States)

    Laslier, Marianne; Ba, Antoine; Hubert-Moy, Laurence; Dufour, Simon

    2017-10-01

    Forest species composition is a fundamental indicator of forest study and management. However, describing forest species composition at large scales and of highly diverse populations remains an issue for which remote sensing can provide significant contribution, in particular, Airborne Laser Scanning (ALS) data. Riparian corridors are good examples of highly valuable ecosystems, with high species richness and large surface areas that can be time consuming and expensive to monitor with in situ measurements. Remote sensing could be useful to study them, but few studies have focused on monitoring riparian tree species using ALS data. This study aimed to determine which metrics derived from ALS data are best suited to identify and map riparian tree species. We acquired very high density leaf-on and leaf-off ALS data along the Sélune River (France). In addition, we inventoried eight main riparian deciduous tree species along the study site. After manual segmentation of the inventoried trees, we extracted 68 morphological and structural metrics from both leaf-on and leaf-off ALS point clouds. Some of these metrics were then selected using Sequential Forward Selection (SFS) algorithm. Support Vector Machine (SVM) classification results showed good accuracy with 7 metrics (0.77). Both leaf-on and leafoff metrics were kept as important metrics for distinguishing tree species. Results demonstrate the ability of 3D information derived from high density ALS data to identify riparian tree species using external and internal structural metrics. They also highlight the complementarity of leaf-on and leaf-off Lidar data for distinguishing riparian tree species.

  6. 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.

  7. Bacterial anoxygenic photosynthesis on plant leaf surfaces

    Czech Academy of Sciences Publication Activity Database

    Atamna-Ismaeel, N.; Finkel, O.; Glaser, F.; von Mering, Ch.; Vorholt, J. A.; Koblížek, Michal; Belkin, S.; Béja, O.

    2012-01-01

    Roč. 4, č. 2 (2012), s. 209-216 ISSN 1758-2229 R&D Projects: GA MŠk(CZ) ED2.1.00/03.0110; GA ČR GAP501/10/0221 Institutional support: RVO:61388971 Keywords : phyllosphere * plant * phyllosphere Subject RIV: EE - Microbiology, Virology Impact factor: 2.708, year: 2012

  8. Relationship between transpiration and amino acid accumulation in Brassica leaf discs treated with cytokinins and fusicoccin

    International Nuclear Information System (INIS)

    Kuraishi, Susumu; Ishikawa, Fumio

    1977-01-01

    Both cytokinins and fusicoccin (FC) stimulated the transpiration and the amino acid accumulation in leaf discs of Brassica campestris var. komatsuna. Enhancement effects were of the same magnitude. Both the accumulation and the transpiration were similarly inhibited when vaseline was smeared on the leaf surface. Abscisic acid (ABA) also inhibited those cytokinin-induced effects. The accumulation of amino acid- 14 C was at the cytokinin- or FC-treated site unless the leaf surface was smeared with vaseline. These facts suggest that cytokinin- or FC-induced amino acid accumulation in leaf is caused by the stimulation of transpiration. (auth.)

  9. Is There a Relation between the Microscopic Leaf Morphology and the Association of Salmonella and Escherichia coli O157:H7 with Iceberg Lettuce Leaves?

    Science.gov (United States)

    VAN der Linden, Inge; Eriksson, Markus; Uyttendaele, Mieke; Devlieghere, Frank

    2016-10-01

    To prevent contamination of fresh produce with enteric pathogens, more insight into mechanisms that may influence the association of these pathogens with fresh produce is needed. In this study, Escherichia coli O157:H7 and Salmonella were chosen as model pathogens, and fresh cut iceberg lettuce was chosen as a model fresh produce type. The morphological structure of iceberg lettuce leaves (stomatal density and length of cell margins per leaf area) was quantified by means of leaf peels and light microscopy of leaves at different stages of development (outer, middle, and inner leaves of the crop) on both leaf sides (abaxial and adxial) and in three leaf regions (top, center, and bottom). The morphology of the top region of the leaves was distinctly different from that of the center and base, with a significantly higher stomatal density (up to five times more stomata), different cell shape, and longer cell margins (two to three times longer). Morphological differences between the same regions of the leaves at different stages of development were smaller or nonsignificant. An attachment assay with two attenuated E. coli O157:H7 strains (84-24h11-GFP and BRMSID 188 GFP) and two Salmonella strains (serovars Thompson and Typhimurium) was performed on different regions of the middle leaves. Our results confirmed earlier reports that these pathogens have a higher affinity for the base of the lettuce leaf than the top. Differences of up to 2.12 log CFU/g were seen ( E. coli O157:H7 86-24h11-GFP). Intermediate attachment occurred in the central region. The higher incidence of preferential bacterial attachment sites such as stomata and cell margins or grooves could not explain the differences observed in the association of the tested pathogens with different regions of iceberg lettuce leaves.

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

    Science.gov (United States)

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

    1974-01-01

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

  11. Air pollutants and the leaf cuticle. Proceedings

    International Nuclear Information System (INIS)

    Percy, K.E.; Jagels, R.; Simpson, C.J.

    1994-01-01

    The leaf surface forms the interface between plants and a deteriorating atmospheric environment. It is, therefore, the first point of contact between plants and air pollutants and presents an effective barrier to pollutant entry. Outermost surfaces of leaves are covered by a thin, lipoidal, non-living membrane called a cuticle. Cuticle integrity is essential to plant survival and has many essential functions, including the prevention of excessive water loss, regulation of solute uptake and protection of sensitive underlying photosynthetic tissues against harmful irradiation such as enhanced UV-B resulting from stratospheric ozone depletion. The physicochemical properties of the cuticle vary greatly between and within species. They are known to be sensitive to change through natural and anthropogenic influences. This book comprises contributions made to a NATO-sponsored Advanced Research Workshop ''Air Pollutants and the Leaf Cuticle'' held October 4-9, 1993 in Fredericton, New Brunswick, Canada. The objective of the ARW was to bring together for the first time international expertise on the subject of air pollutant interactions with the cuticle. In order to facilitate a state-of-science review, the ARW was structured around four themes. They were as follows: 1. Cuticular physicochemical characteristics, physiological, regulatory, and protective roles. 2. Effects, mechanisms, and consequences of air pollutant interaction with leaf cuticles. 3. Non-anthropogenic and environmental influences on the cuticle and potential of the cuticle for biomonitoring and critical levels mapping. 4. New developments in experimental methodology and analytical techniques. (orig./vhe)

  12. Adaxial/abaxial specification in the regulation of photosynthesis and stomatal opening with respect to light orentation and growth with CO2 enrichment in the C4 species Paspalum dilatatum

    NARCIS (Netherlands)

    Soares, A.S.; Discoll, S.P.; Olmos, E.; Harbinson, J.; Arrabaca, M.C.

    2008-01-01

    Whole-plant morphology, leaf structure and composition were studied together with the effects of light orientation on the dorso-ventral regulation of photosynthesis and stomatal conductance in Paspalum dilatatum cv. Raki plants grown for 6 wk at either 350 or 700 µl l¿1 CO2. Plant biomass was

  13. Gold leaf counter electrodes for dye-sensitized solar cells

    Science.gov (United States)

    Shimada, Kazuhiro; Toyoda, Takeshi

    2018-03-01

    In this study, a gold leaf 100 nm thin film is used as the counter electrode in dye-sensitized solar cells. The traditional method of hammering gold foil to obtain a thin gold leaf, which requires only small amounts of gold, was employed. The gold leaf was then attached to the substrate using an adhesive to produce the gold electrode. The proposed approach for fabricating counter electrodes is demonstrated to be facile and cost-effective, as opposed to existing techniques. Compared with electrodes prepared with gold foil and sputtered gold, the gold leaf counter electrode demonstrates higher catalytic activity with a cobalt-complex electrolyte and higher cell efficiency. The origin of the improved performance was investigated by surface morphology examination (scanning electron microscopy), various electrochemical analyses (cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy), and crystalline analysis (X-ray diffractometry).

  14. (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.

  15. The leaf angle distribution of natural plant populations: assessing the canopy with a novel software tool.

    Science.gov (United States)

    Müller-Linow, Mark; Pinto-Espinosa, Francisco; Scharr, Hanno; Rascher, Uwe

    2015-01-01

    Three-dimensional canopies form complex architectures with temporally and spatially changing leaf orientations. Variations in canopy structure are linked to canopy function and they occur within the scope of genetic variability as well as a reaction to environmental factors like light, water and nutrient supply, and stress. An important key measure to characterize these structural properties is the leaf angle distribution, which in turn requires knowledge on the 3-dimensional single leaf surface. Despite a large number of 3-d sensors and methods only a few systems are applicable for fast and routine measurements in plants and natural canopies. A suitable approach is stereo imaging, which combines depth and color information that allows for easy segmentation of green leaf material and the extraction of plant traits, such as leaf angle distribution. We developed a software package, which provides tools for the quantification of leaf surface properties within natural canopies via 3-d reconstruction from stereo images. Our approach includes a semi-automatic selection process of single leaves and different modes of surface characterization via polygon smoothing or surface model fitting. Based on the resulting surface meshes leaf angle statistics are computed on the whole-leaf level or from local derivations. We include a case study to demonstrate the functionality of our software. 48 images of small sugar beet populations (4 varieties) have been analyzed on the base of their leaf angle distribution in order to investigate seasonal, genotypic and fertilization effects on leaf angle distributions. We could show that leaf angle distributions change during the course of the season with all varieties having a comparable development. Additionally, different varieties had different leaf angle orientation that could be separated in principle component analysis. In contrast nitrogen treatment had no effect on leaf angles. We show that a stereo imaging setup together with the

  16. A cytochemical and immunocytochemical analysis of the wall labyrinth apparatus in leaf transfer cells in Elodea canadensis.

    Science.gov (United States)

    Ligrone, Roberto; Vaughn, Kevin C; Rascio, Nicoletta

    2011-04-01

    Transfer cells are plant cells specialized in apoplast/symplast transport and characterized by a distinctive wall labyrinth apparatus. The molecular architecture and biochemistry of the labyrinth apparatus are poorly known. The leaf lamina in the aquatic angiosperm Elodea canadensis consists of only two cell layers, with the abaxial cells developing as transfer cells. The present study investigated biochemical properties of wall ingrowths and associated plasmalemma in these cells. Leaves of Elodea were examined by light and electron microscopy and ATPase activity was localized cytochemically. Immunogold electron microscopy was employed to localize carbohydrate epitopes associated with major cell wall polysaccharides and glycoproteins. The plasmalemma associated with the wall labyrinth is strongly enriched in light-dependent ATPase activity. The wall ingrowths and an underlying wall layer share an LM11 epitope probably associated with glucuronoarabinoxylan and a CCRC-M7 epitope typically associated with rhamnogalacturonan I. No labelling was observed with LM10, an antibody that recognizes low-substituted and unsubstituted xylan, a polysaccharide consistently associated with secondary cell walls. The JIM5 and JIM7 epitopes, associated with homogalacturonan with different degrees of methylation, appear to be absent in the wall labyrinth but present in the rest of cell walls. The wall labyrinth apparatus of leaf transfer cells in Elodea is a specialized structure with distinctive biochemical properties. The high level of light-dependent ATPase activity in the plasmalemma lining the wall labyrinth is consistent with a formerly suggested role of leaf transfer cells in enhancing inorganic carbon inflow. The wall labyrinth is a part of the primary cell wall. The discovery that the wall ingrowths in Elodea have an antibody-binding pattern divergent, in part, from that of the rest of cell wall suggests that their carbohydrate composition is modulated in relation to transfer

  17. Acute and Sub-acute Toxicity Profile of Aqueous Leaf Extract of ...

    African Journals Online (AJOL)

    information on the safety/toxicity of the aqueous extract of Nymphaea .... automatic chemistry analyzer (Abaxis Inc. Union. City, CA .... play central role in gaseous exchange and inter- compartmental .... OECD guidelines for testing of chemicals ...

  18. 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.

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

    Science.gov (United States)

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

  20. Effect of Plant Growth Regulators on Leaf Number, Leaf Area and Leaf Dry Matter in Grape

    Directory of Open Access Journals (Sweden)

    Zahoor Ahmad BHAT

    2011-03-01

    Full Text Available Influence of phenylureas (CPPU and brassinosteriod (BR along with GA (gibberellic acid were studied on seedless grape vegetative characteristics like leaf number, leaf area and leaf dry matter. Growth regulators were sprayed on the vines either once (7 days after fruit set or 15 days after fruit set or twice (7+15 days after fruit set. CPPU 2 ppm+BR 0.4 ppm+GA 25 ppm produced maximum number of leaves (18.78 while as untreated vines produced least leaf number (16.22 per shoot. Maximum leaf area (129.70 cm2 and dry matter content (26.51% was obtained with higher CPPU (3 ppm and BR (0.4 ppm combination along with GA 25 ppm. Plant growth regulators whether naturally derived or synthetic are used to improve the productivity and quality of grapes. The relatively high value of grapes justifies more expensive inputs. A relatively small improvement in yield or fruit quality can justify the field application of a very costly product. Application of new generation growth regulators like brassinosteroids and phenylureas like CPPU have been reported to increase the leaf number as well as leaf area and dry matter thereby indirectly influencing the fruit yield and quality in grapes.

  1. 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

  2. Agave Americana Leaf Fibers

    Directory of Open Access Journals (Sweden)

    Ashish Hulle

    2015-02-01

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

  3. Cytotoxicity testing of aqueous extract of bitter leaf (Vernonia ...

    African Journals Online (AJOL)

    Cytotoxicity testing of aqueous extract of bitter leaf (Vernonia amygdalina Del) and sniper. 1000EC (2,3 ... man and animals.1 It is estimated that 80% of the popula- ..... evaluation of waste, surface and ground water quality using the Allium test ...

  4. Interaction between Silver Nanoparticles and Spinach Leaf

    Science.gov (United States)

    Tian, Y.; Li, H.; Zhang, Y.; Riser, E.; He, S.; Zhang, W.

    2013-12-01

    Interactions of engineered nanoparticles (ENPs) with plant surfaces are critical to assessing the bioavailability of ENPs to edible plants and to further evaluating impacts of ENPs on ecological health and food safety. Silver nanoparticles (i.e., nanoAg) could enter the agroecosystems either as an active ingredient in pesticides or from other industrial and consumer applications. Thus, in the events of pesticide application, rainfall, and irrigation, vegetable leaves could become in contact and then interact with nanoAg. The present study was to assess whether the interaction of nanoAg with spinach leaves can be described by classical sorption models and to what extent it depends on and varies with dispersion methods, environmental temperature, and ion release. We investigated the stability and ion release of nanoAg dispersed by sodium dodecyl sulfate (SDS, 1%) and humic acid (HA, 10 mg C/L) solutions, as well as sorption and desorption of nanoAg on and from the fresh spinach leaf. Results showed SDS-nanoAg released about 2%-8% more Ag ion than HA-nanoAg. The sorption of Ag ion, described by the Freundlich model in the initial concentration range of 0.6-50 mg/L, was 2-4 times higher than that of nanoAg. The sorption of nanoAg on spinach leaf can be fitted by the Langmuir model, and the maximum sorption amount of HA-nanoAg and SDS-nanoAg was 0.21 and 0.41 mg/g, respectively. The higher sorption of SDS-nanoAg relative to that of HA-nanoAg could be partially resulted from the higher release of Ag ion from the former. The maximum desorption amount of HA-nanoAg and SDS-nanoAg in 1% SDS solution was 0.08 and 0.10 mg/g, respectively. NanoAg attachment on and its penetration to the spinach leaf was visualized by the Scanning Electron Microscope equipped with an Energy Dispersive Spectrometer (SEM-EDS). It is equally important that the less sorption of nanoAg under low environmental temperature could be partially due to the closure of stomata, as verified by SEM-EDS. Cyto

  5. 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...

  6. 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...

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

    Science.gov (United States)

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

    2016-11-01

    Leaf photosynthesis is determined by biochemical properties and anatomical features. Here we developed a three-dimensional leaf model that can be used to evaluate the internal light environment of a leaf and its implications for whole-leaf electron transport rates (J). This model includes (i) the basic components of a leaf, such as the epidermis, palisade and spongy tissues, as well as the physical dimensions and arrangements of cell walls, vacuoles and chloroplasts; and (ii) an efficient forward ray-tracing algorithm, predicting the internal light environment for light of wavelengths between 400 and 2500nm. We studied the influence of leaf anatomy and ambient light on internal light conditions and J The results show that (i) different chloroplasts can experience drastically different light conditions, even when they are located at the same distance from the leaf surface; (ii) bundle sheath extensions, which are strips of parenchyma, collenchyma or sclerenchyma cells connecting the vascular bundles with the epidermis, can influence photosynthetic light-use efficiency of leaves; and (iii) chloroplast positioning can also influence the light-use efficiency of leaves. Mechanisms underlying leaf internal light heterogeneity and implications of the heterogeneity for photoprotection and for the convexity of the light response curves are discussed. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  8. Microscopic, physicochemical and chromatographic fingerprints of ...

    African Journals Online (AJOL)

    Polygonal epidermal cells and numerous uniseriate, unicellular trichomes were also present. Quantitative leaf analysis revealed the following: stomata number on abaxial surface 445, stomata index 30.7, palisade ratio 17.1, vein- islet number 17.3 and vein- termination number 14.2. Chemomicroscopic characters present ...

  9. Pharmacognostic evaluation of the leaves and stem-bark of ...

    African Journals Online (AJOL)

    The microscopy revealed the dorsiventral nature of the leaf and was observed to be hypostomatic with anomocytic type of stomata, with numerous unicellular covering and glandular trichomes on the abaxial surface. Chemomicroscopic characters present include; lignin, starch, cellulose, tannin, suberin and calcium oxalate ...

  10. Sampling plans for pest mites on physic nut.

    Science.gov (United States)

    Rosado, Jander F; Sarmento, Renato A; Pedro-Neto, Marçal; Galdino, Tarcísio V S; Marques, Renata V; Erasmo, Eduardo A L; Picanço, Marcelo C

    2014-08-01

    The starting point for generating a pest control decision-making system is a conventional sampling plan. Because the mites Polyphagotarsonemus latus and Tetranychus bastosi are among the most important pests of the physic nut (Jatropha curcas), in the present study, we aimed to establish sampling plans for these mite species on physic nut. Mite densities were monitored in 12 physic nut crops. Based on the obtained results, sampling of P. latus and T. bastosi should be performed by assessing the number of mites per cm(2) in 160 samples using a handheld 20× magnifying glass. The optimal sampling region for T. bastosi is the abaxial surface of the 4th most apical leaf on the branch of the middle third of the canopy. On the abaxial surface, T. bastosi should then be observed on the side parts of the middle portion of the leaf, near its edge. As for P. latus, the optimal sampling region is the abaxial surface of the 4th most apical leaf on the branch of the apical third of the canopy on the abaxial surface. Polyphagotarsonemus latus should then be assessed on the side parts of the leaf's petiole insertion. Each sampling procedure requires 4 h and costs US$ 7.31.

  11. Specklinia lugduno-batavae (Pleurothallidinae: Orchidaceae), a new species in the S. digitalis group

    NARCIS (Netherlands)

    Karremans, A.P.; Bogarín, D.; Gravendeel, B.

    2015-01-01

    Specklinia lugduno-batavae from the Caribbean lowlands of Nicaragua and Costa Rica is formally described and illustrated. The new species belongs to the Specklinia digitalis group and can be recognised by the creeping habit, purple spotted abaxial surface of the leaf and the almost immaculate

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

    Science.gov (United States)

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

    2013-04-01

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

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

    Science.gov (United States)

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

    2012-10-01

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

  14. Global variability in leaf respiration in relation to climate, plant functional types and leaf traits.

    Science.gov (United States)

    Atkin, Owen K; Bloomfield, Keith J; Reich, Peter B; Tjoelker, Mark G; Asner, Gregory P; Bonal, Damien; Bönisch, Gerhard; Bradford, Matt G; Cernusak, Lucas A; Cosio, Eric G; Creek, Danielle; Crous, Kristine Y; Domingues, Tomas F; Dukes, Jeffrey S; Egerton, John J G; Evans, John R; Farquhar, Graham D; Fyllas, Nikolaos M; Gauthier, Paul P G; Gloor, Emanuel; Gimeno, Teresa E; Griffin, Kevin L; Guerrieri, Rossella; Heskel, Mary A; Huntingford, Chris; Ishida, Françoise Yoko; Kattge, Jens; Lambers, Hans; Liddell, Michael J; Lloyd, Jon; Lusk, Christopher H; Martin, Roberta E; Maksimov, Ayal P; Maximov, Trofim C; Malhi, Yadvinder; Medlyn, Belinda E; Meir, Patrick; Mercado, Lina M; Mirotchnick, Nicholas; Ng, Desmond; Niinemets, Ülo; O'Sullivan, Odhran S; Phillips, Oliver L; Poorter, Lourens; Poot, Pieter; Prentice, I Colin; Salinas, Norma; Rowland, Lucy M; Ryan, Michael G; Sitch, Stephen; Slot, Martijn; Smith, Nicholas G; Turnbull, Matthew H; VanderWel, Mark C; Valladares, Fernando; Veneklaas, Erik J; Weerasinghe, Lasantha K; Wirth, Christian; Wright, Ian J; Wythers, Kirk R; Xiang, Jen; Xiang, Shuang; Zaragoza-Castells, Joana

    2015-04-01

    Leaf dark respiration (Rdark ) is an important yet poorly quantified component of the global carbon cycle. Given this, we analyzed a new global database of Rdark and associated leaf traits. Data for 899 species were compiled from 100 sites (from the Arctic to the tropics). Several woody and nonwoody plant functional types (PFTs) were represented. Mixed-effects models were used to disentangle sources of variation in Rdark . Area-based Rdark at the prevailing average daily growth temperature (T) of each site increased only twofold from the Arctic to the tropics, despite a 20°C increase in growing T (8-28°C). By contrast, Rdark at a standard T (25°C, Rdark (25) ) was threefold higher in the Arctic than in the tropics, and twofold higher at arid than at mesic sites. Species and PFTs at cold sites exhibited higher Rdark (25) at a given photosynthetic capacity (Vcmax (25) ) or leaf nitrogen concentration ([N]) than species at warmer sites. Rdark (25) values at any given Vcmax (25) or [N] were higher in herbs than in woody plants. The results highlight variation in Rdark among species and across global gradients in T and aridity. In addition to their ecological significance, the results provide a framework for improving representation of Rdark in terrestrial biosphere models (TBMs) and associated land-surface components of Earth system models (ESMs). © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  15. Coordination of Leaf Photosynthesis, Transpiration, and Structural Traits in Rice and Wild Relatives (Genus Oryza).

    Science.gov (United States)

    Giuliani, Rita; Koteyeva, Nuria; Voznesenskaya, Elena; Evans, Marc A; Cousins, Asaph B; Edwards, Gerald E

    2013-07-01

    The genus Oryza, which includes rice (Oryza sativa and Oryza glaberrima) and wild relatives, is a useful genus to study leaf properties in order to identify structural features that control CO(2) access to chloroplasts, photosynthesis, water use efficiency, and drought tolerance. Traits, 26 structural and 17 functional, associated with photosynthesis and transpiration were quantified on 24 accessions (representatives of 17 species and eight genomes). Hypotheses of associations within, and between, structure, photosynthesis, and transpiration were tested. Two main clusters of positively interrelated leaf traits were identified: in the first cluster were structural features, leaf thickness (Thick(leaf)), mesophyll (M) cell surface area exposed to intercellular air space per unit of leaf surface area (S(mes)), and M cell size; a second group included functional traits, net photosynthetic rate, transpiration rate, M conductance to CO(2) diffusion (g(m)), stomatal conductance to gas diffusion (g(s)), and the g(m)/g(s) ratio.While net photosynthetic rate was positively correlated with gm, neither was significantly linked with any individual structural traits. The results suggest that changes in gm depend on covariations of multiple leaf (S(mes)) and M cell (including cell wall thickness) structural traits. There was an inverse relationship between Thick(leaf) and transpiration rate and a significant positive association between Thick(leaf) and leaf transpiration efficiency. Interestingly, high g(m) together with high g(m)/g(s) and a low S(mes)/g(m) ratio (M resistance to CO(2) diffusion per unit of cell surface area exposed to intercellular air space) appear to be ideal for supporting leaf photosynthesis while preserving water; in addition, thick M cell walls may be beneficial for plant drought tolerance.

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

    Science.gov (United States)

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

    2006-12-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

  18. Waiting for the Leaf; Warten auf den Leaf

    Energy Technology Data Exchange (ETDEWEB)

    Wilms, Jan

    2012-01-15

    Nissan will be the first manufacturer to launch an electric vehicle of the VW Golf category in the German market. With a mileage of about 170 km and a roomy passenger compartment, the Leaf promises much comfort. In the US market, it was launched two years ago. Was it worth while waiting for?.

  19. Effect of nitrogen supply on leaf appearance, leaf growth, leaf nitrogen economy and photosynthetic capacity in maize (Zea mays L.)

    NARCIS (Netherlands)

    Vos, J.; Putten, van der P.E.L.; Birch, C.J.

    2005-01-01

    Leaf area growth and nitrogen concentration per unit leaf area, Na (g m-2 N) are two options plants can use to adapt to nitrogen limitation. Previous work indicated that potato (Solanum tuberosum L.) adapts the size of leaves to maintain Na and photosynthetic capacity per unit leaf area. This paper

  20. Spectral reflectance relationships to leaf water stress

    Science.gov (United States)

    Ripple, William J.

    1986-01-01

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

  1. Method of manufacturing leaf spring for PWR type reactor fuel assembly

    International Nuclear Information System (INIS)

    Yokoyama, Takashi; Mori, Kazuma.

    1991-01-01

    A leaf spring is manufactured by precision casting using corrosion resistant and heat resistant high strength steel material and, subsequently, the surface is treated with slight surface grinding or pickling. Further, for increasing resistance to stress corrosion cracks (SCC), shot blasting is applied to the surface. This reduces the surface roughness (Rmax) of the leaf spring to less than 0.005 mm, and the dimensional tolerance can be set to +0.005 mm, -0.0 mm. In this way, since the surface roughness is so small as not causing fabrication injury to the surface, the material has sufficient resistance to SCC. Further, since the accuracy for the plate thickness is high, stress distribution as designed can be attained to prevent stress concentration. Then, if a casting die is once prepared, the casting mass production is enabled to reduce the manufacturing cost for the leaf spring. (T.M.)

  2. LEAF RESIDUE DECOMPOSITION OF SELECTED ATLANTIC FOREST TREE SPECIES

    Directory of Open Access Journals (Sweden)

    Helga Dias Arato

    2018-02-01

    Full Text Available ABSTRACT Biogeochemical cycling is essential to establish and maintain plant and animal communities. Litter is one of main compartments of this cycle, and the kinetics of leaf decomposition in forest litter depend on the chemical composition and environmental conditions. This study evaluated the effect of leaf composition and environmental conditions on leaf decomposition of native Atlantic Forest trees. The following species were analyzed: Mabea fistulifera Mart., Bauhinia forficata Link., Aegiphila sellowiana Cham., Zeyheria tuberculosa (Vell, Luehea grandiflora Mart. et. Zucc., Croton floribundus Spreng., Trema micrantha (L Blume, Cassia ferruginea (Schrad Schrad ex DC, Senna macranthera (DC ex Collad. H. S. Irwin and Barney and Schinus terebinthifolius Raddi (Anacardiaceae. For each species, litter bags were distributed on and fixed to the soil surface of soil-filled pots (in a greenhouse, or directly to the surface of the same soil type in a natural forest (field. Every 30 days, the dry weight and soil basal respiration in both environments were determined. The cumulative decomposition of leaves varied according to the species, leaf nutrient content and environment. In general, the decomposition rate was lowest for Aegiphila sellowiana and fastest for Bauhinia forficate and Schinus terebinthifolius. This trend was similar under the controlled conditions of a greenhouse and in the field. The selection of species with a differentiated decomposition pattern, suited for different stages of the recovery process, can help improve soil restoration.

  3. An evolutionary perspective on leaf economics : Phylogenetics of leaf mass per area in vascular plants

    NARCIS (Netherlands)

    Flores, Olivier; Garnier, Eric; Wright, Ian J.; Reich, Peter B.; Pierce, Simon; Diaz, Sandra; Pakeman, Robin J.; Rusch, Graciela M.; Bernard-Verdier, Maud; Testi, Baptiste; Bakker, Jan P.; Bekker, Renee M.; Cerabolini, Bruno E. L.; Ceriani, Roberta M.; Cornu, Guillaume; Cruz, Pablo; Delcamp, Matthieu; Dolezal, Jiri; Eriksson, Ove; Fayolle, Adeline; Freitas, Helena; Golodets, Carly; Gourlet-Fleury, Sylvie; Hodgson, John G.; Brusa, Guido; Kleyer, Michael; Kunzmann, Dieter; Lavorel, Sandra; Papanastasis, Vasilios P.; Perez-Harguindeguy, Natalia; Vendramini, Fernanda; Weiher, Evan

    In plant leaves, resource use follows a trade-off between rapid resource capture and conservative storage. This "worldwide leaf economics spectrum" consists of a suite of intercorrelated leaf traits, among which leaf mass per area, LMA, is one of the most fundamental as it indicates the cost of leaf

  4. The Nissan LEAF electric powertrain

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

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

    Science.gov (United States)

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

    2013-04-01

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

  6. 7 CFR 30.2 - Leaf tobacco.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf tobacco. 30.2 Section 30.2 Agriculture... Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO STOCKS AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of Grades § 30.2 Leaf...

  7. 7 CFR 29.3035 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.3035 Section 29.3035 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Leaf structure. The cell development of a leaf as indicated by its porosity or solidity. (See Elements...

  8. 7 CFR 29.6023 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.6023 Section 29.6023 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6023 Leaf structure. The cell development of a leaf as indicated by its...

  9. 7 CFR 29.1030 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.1030 Section 29.1030 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 92) § 29.1030 Leaf structure. The cell development of a leaf as indicated by its porosity. (See...

  10. 7 CFR 29.3527 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.3527 Section 29.3527 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 95) § 29.3527 Leaf structure. The cell development of a leaf as indicated by its porosity. (See...

  11. 7 CFR 29.3526 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.3526 Section 29.3526 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 95) § 29.3526 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results from handling...

  12. 7 CFR 29.3034 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.3034 Section 29.3034 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Leaf scrap. A by-product of unstemmed tobacco. Leaf scrap results from handling unstemmed tobacco and...

  13. 7 CFR 29.6022 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.6022 Section 29.6022 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6022 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results...

  14. Weak leaf photosynthesis and nutrient content relationships from tropical vegetation

    Science.gov (United States)

    Domingues, T. F.; Ishida, F. Y.; Feldpaush, T.; Saiz, G.; Grace, J.; Meir, P.; Lloyd, J.

    2015-12-01

    Evergreen rain forests and savannas are the two major vegetations of tropical land ecosystems, in terms of land area, biomass, biodiversity, biogeochemical cycles and rates of land use change. Mechanistically understanding ecosystem functioning on such ecosystems is still far from complete, but important for generation of future vegetation scenarios in response to global changes. Leaf photosynthetic rates is a key processes usually represented on land surface-atmosphere models, although data from tropical ecosystems is scarce, considering the high biodiversity they contain. As a shortcut, models usually recur to relationships between leaf nutrient concentration and photosynthetic rates. Such strategy is convenient, given the possibility of global datasets on leave nutrients derived from hyperspectral remote sensing data. Given the importance of Nitrogen on enzyme composition, this nutrient is usually used to infer photosynthetic capacity of leaves. Our experience, based on individual measurements on 1809 individual leaves from 428 species of trees and shrubs naturally occurring on tropical forests and savannas from South America, Africa and Australia, indicates that the relationship between leaf nitrogen and its assimilation capacity is weak. Therefore, leaf Nitrogen alone is a poor predictor of photosynthetic rates of tropical vegetation. Phosphorus concentrations from tropical soils are usually low and is often implied that this nutrient limits primary productivity of tropical vegetation. Still, phosphorus (or other nutrients) did not exerted large influence over photosynthetic capacity, although potassium influenced vegetation structure and function. Such results draw attention to the risks of applying universal nitrogen-photosynthesis relationships on biogeochemical models. Moreover, our data suggests that affiliation of plant species within phylogenetic hierarchy is an important aspect in understanding leaf trait variation. The lack of a strong single

  15. Non-linear direct effects of acid rain on leaf photosynthetic rate of terrestrial plants.

    Science.gov (United States)

    Dong, Dan; Du, Enzai; Sun, Zhengzhong; Zeng, Xuetong; de Vries, Wim

    2017-12-01

    Anthropogenic emissions of acid precursors have enhanced global occurrence of acid rain, especially in East Asia. Acid rain directly suppresses leaf function by eroding surface waxes and cuticle and leaching base cations from mesophyll cells, while the simultaneous foliar uptake of nitrates in rainwater may directly benefit leaf photosynthesis and plant growth, suggesting a non-linear direct effect of acid rain. By synthesizing data from literature on acid rain exposure experiments, we assessed the direct effects of acid rain on leaf photosynthesis across 49 terrestrial plants in China. Our results show a non-linear direct effect of acid rain on leaf photosynthetic rate, including a neutral to positive effect above pH 5.0 and a negative effect below that pH level. The acid rain sensitivity of leaf photosynthesis showed no significant difference between herbs and woody species below pH 5.0, but the impacts above that pH level were strongly different, resulting in a significant increase in leaf photosynthetic rate of woody species and an insignificant effect on herbs. Our analysis also indicates a positive effect of the molar ratio of nitric versus sulfuric acid in the acid solution on leaf photosynthetic rate. These findings imply that rainwater acidity and the composition of acids both affect the response of leaf photosynthesis and therefore result in a non-linear direct effect. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    1998-05-01

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

  17. Styloid crystals in Claoxylon (Euphorbiaceae) and allies (Claoxylinae) with notes on leaf anatomy Botanical Journal of the Linnean Society

    NARCIS (Netherlands)

    Kabouw, P.; Welzen, van P.C.; Baas, P.; Heuven, Van B.J.

    2008-01-01

    Claoxylon and Micrococca are the only Euphorbiaceae genera that have rough dried leaves (fresh ones are smooth) because of protruding styloid (needle-like) crystals more or less perpendicular to the leaf surface, which perforate the epidermis and cuticle. A broad leaf anatomical study of the

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

    DEFF Research Database (Denmark)

    Bøgh, Eva; Houborg, R; Bienkowski, J

    2013-01-01

    Leaf nitrogen and leaf surface area influence the exchange of gases between terrestrial ecosystems and the atmosphere, and they play a significant role in the global cycles of carbon, nitrogen and water. Remote sensing data from satellites can be used to estimate leaf area index (LAI), leaf......). Predictabilities of SVIs and REGFLEC simulations generally improved when constrained to single land use categories (wheat, maize, barley, grass) across the European landscapes, reflecting sensitivity to canopy structures. Predictability further improved when constrained to local (10 × 10 km2) landscapes, thereby...

  19. Leaf dimorphism of Microgramma squamulosa (Polypodiaceae: a qualitative and quantitative analysis focusing on adaptations to epiphytism

    Directory of Open Access Journals (Sweden)

    Ledyane Dalgallo Rocha

    2013-03-01

    Full Text Available The epiphytic fern Microgramma squamulosa occurs in the Neotropics and shows dimorphic sterile and fertile leaves. The present study aimed to describe and compare qualitatively and quantitatively macroscopic and microscopic structural characteristics of the dimorphic leaves of M. squamulosa, to point more precisely those characteristics which may contribute to epiphytic adaptations. In June 2009, six isolated host trees covered by M. squamulosa were selected close to the edge of a semi-deciduous seasonal forest fragment in the municipality of Novo Hamburgo, State of Rio Grande do Sul, Brazil. Macroscopic and microscopic analyzes were performed from 192 samples for each leaf type, and permanent and semi-permanent slides were prepared. Sections were observed under light microscopy using image capture software to produce illustrations and scales, as well as to perform quantitative analyses. Fertile and sterile leaves had no qualitative structural differences, being hypostomatous and presenting uniseriate epidermis, homogeneous chlorenchyma, amphicribal vascular bundle, and hypodermis. The presence of hypodermal tissue and the occurrence of stomata at the abaxial face are typical characteristics of xeromorphic leaves. Sterile leaves showed significantly larger areas (14.80cm², higher sclerophylly index (0.13g/cm² and higher stomatal density (27.75stomata/mm² than fertile leaves. The higher sclerophylly index and the higher stomatal density observed in sterile leaves are features that make these leaves more xeromorphic, enhancing their efficiency to deal with limited water availability in the epiphytic environment, compared to fertile leaves.El helecho epífito Microgramma squamulosa se encuentra en el Neotrópico y tiene hojas estériles y fértiles dimorfas. El objetivo de este estudio fue describir y comparar cuantitativa y cualitativamente la organización estructural de las hojas de la M. squamulosa, investigando las características morfol

  20. A sensitive hydrogen peroxide sensor based on leaf-like silver

    International Nuclear Information System (INIS)

    Meng, Zuchao; Zhang, Mingyin; Zhang, Hongfang; Zheng, Jianbin

    2014-01-01

    A novel non-enzymatic hydrogen peroxide sensor based on leaf-like silver was constructed. The leaf-like silver was synthesized on the surface of L-cysteine (L-cys) by electrodeposition. Scanning electron microscopy and electrochemical techniques were used to characterize the leaf-like silver nanoparticles. The sensor showed high electrocatalytic activity towards the reduction of hydrogen peroxide. A wide linear range of 2.5–1.5 mM with a low detection limit of 0.7 µM was obtained. Excellent electrocatalytic activity, large surface-to-volume ratio and efficient electron transport properties of leaf-like silver have enabled stable and highly sensitive performance for the non-enzymatic hydrogen peroxide sensor. (paper)

  1. Analysis of Peanut Leaf Proteome

    DEFF Research Database (Denmark)

    Ramesh, R.; Suravajhala, Prashanth; Pechan, T.

    2010-01-01

    Peanut (Arachis hypogaea) is one of the most important sources of plant protein. Current selection of genotypes requires molecular characterization of available populations. Peanut genome database has several EST cDNAs which can be used to analyze gene expression. Analysis of proteins is a direct...... approach to define function of their associated genes. Proteome analysis linked to genome sequence information is critical for functional genomics. However, the available protein expression data is extremely inadequate. Proteome analysis of peanut leaf was conducted using two-dimensional gel...... electrophoresis in combination with sequence identification using MALDI/TOF to determine their identity and function related to growth, development and responses to stresses. Peanut leaf proteins were resolved into 300 polypeptides with pI values between 3.5 and 8.0 and relative molecular masses from 12 to 100 k...

  2. 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.

  3. A new species of Cinnamomum (Lauraceae) from the Bladen Nature Reserve, southern Belize.

    Science.gov (United States)

    Brewer, Steven W; Stott, Gail L

    2017-01-01

    A new species in the Lauraceae, Cinnamomum bladenense S.W. Brewer & G.L. Stott, is described from the Bladen Nature Reserve in southern Belize. The new species is similar to Cinnamomum brenesii (Standl.) Kosterm., from which it differs by its much smaller, narrowly-campanulate flowers, its inner tepals glabrous abaxially, its shorter petioles, its minutely sericeous younger twigs, and its abaxial leaf surfaces not glaucous and with prominent secondary venation. A description, preliminary conservation assessment, and photographs of the species as well as a key to and notes on the Cinnamomum of Belize are provided.

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

    Science.gov (United States)

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

    2018-02-01

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

  5. Tuning Transpiration by Interfacial Solar Absorber‐Leaf Engineering

    Science.gov (United States)

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

    2017-01-01

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

  6. Leaf Surface Scanning Electron Microscopy of 16 Mulberry Genotypes (Morus spp. with Respect to their Feeding Value in Silkworm (Bombyx mori L. Rearing Microscopía Electrónica de Barrido de la Superficie Foliar de 16 Genotipos de Morus spp. en Relación a su Valor Alimenticio para Crianza del Gusano de la Seda (Bombyx mori L.

    Directory of Open Access Journals (Sweden)

    B.K Singhal

    2010-06-01

    Full Text Available Mulberry (Morus spp. is the only silkworm (Bombyx mori L. food plant. In Indian sub tropics, S-146 is the only popular and ruling mulberry genotype for silkworm rearing. As a result, mulberry leaf availability is always the limiting factor, and therefore, sub tropics are contributing less than 1% of the country’s total silk production compared with more than 60% under tropical conditions. Besides climatic conditions, this is due to a very limited number of mulberry genotypes available in this region for silkworm rearing. However, in the mean time, 15 mulberry genotypes viz. ‘Tr-10’,‘Chinese White’,‘K-2’,‘Sujanpur Local’,‘BC2-59’,‘S-1635’,‘C-1730’,‘Mandalaya’,‘S-30’‘(Vishala,‘RFS-175’,‘Anantha’,‘C-2016’,‘C-2017’,‘S-41’ and‘V-1’ were also introduced in the sub tropics, but remained unexplored. In sericulture, leaf surface is also an important parameter for, both, the silkworm’s acceptability of not having any feeding impediment and the mulberry improvement programs. The objective of this study was to explore the possibilities of using these 16 mulberry genotypes for their leaf surface characteristics by scanning electron microscopy and using them for sericulture. Based on leaf yield, stomatal size, stomatal number per unit of area and trichomes and idioblasts length, these genotypes were grouped into different categories. The mulberry genotype ‘Mandalaya’, in addition to the ruling genotype ‘S-146’ excelled because of their higher leaf yield and desired leaf surface characteristics. Furthermore, the genotypes ‘K-2’, ‘S-41’ and ‘Sujanpur Local’ are also suggested to develop high yield mulberry genotypes in the Indian sub tropics.La morera (Morus spp. es la única planta de alimento para el gusano de la seda (Bombyx mori L.. En los sub-trópicos de la India, ‘S-146’ es el único genotipo popular y predominante de morera para criarlo. Como resultado, la

  7. Leveraging multiple datasets for deep leaf counting

    OpenAIRE

    Dobrescu, Andrei; Giuffrida, Mario Valerio; Tsaftaris, Sotirios A

    2017-01-01

    The number of leaves a plant has is one of the key traits (phenotypes) describing its development and growth. Here, we propose an automated, deep learning based approach for counting leaves in model rosette plants. While state-of-the-art results on leaf counting with deep learning methods have recently been reported, they obtain the count as a result of leaf segmentation and thus require per-leaf (instance) segmentation to train the models (a rather strong annotation). Instead, our method tre...

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

    International Nuclear Information System (INIS)

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

    1994-01-01

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

  9. Derivation of elastic stiffness formula for leaf type HDS and conceptual design of leaf type HDS of SMART FA

    Energy Technology Data Exchange (ETDEWEB)

    Song, Kee Nam; Kang, Heung Seok; Yoon, Kyung Ho; Suh, Jung Min; Lee, Jin Seok

    1997-12-01

    Based on the strain energy method and Euler beam theory, an elastic stiffness formula for the leaf type HDS, now widely used as the holddown spring for the FA of Westinghouse type PWRs, has been derived. Through comparisons with the characteristic test results of the test produced HDSs, it has been found that the derived formula is useful to reliably estimate an elastic stiffness with material properties and the geometric data of an HDS. Through sensitivity analysis of HDS`s elastic stiffness, the elastic stiffness sensitivity with respect to different design variables was identified, as well as the design variables having remarkable sensitivity. In addition, finite element analysis using surface-to-surface contact elements on the contact surface between the leaves shows that the analysis results are in good agreement with the elastic stiffness determined from the derived formula. It is therefore expected that the finite element model and the analysis method will be useful in the analysis of the elasto-plastic behavior of the leaf type HDS in the future. To both reduce the cobalt content, which is considered to be the source of radioactive contamination in the reactor core, and to design the HDS to meet the holddown requirements of the SMART FA, a conceptual design for the HDS of the SMART FA has been performed through two analyses of the elastic characteristics of the HDS : the possibility of substitution of the leaf spring`s material from Inconel 718 to Zircaloy and the effects on the HDS`s elastic characteristics according to the variation of leaf thickness and the number of leaves composing the HDS. (author). 34 refs., 33 tabs., 37 figs.

  10. Leaf sequencing algorithms for segmented multileaf collimation

    International Nuclear Information System (INIS)

    Kamath, Srijit; Sahni, Sartaj; Li, Jonathan; Palta, Jatinder; Ranka, Sanjay

    2003-01-01

    The delivery of intensity-modulated radiation therapy (IMRT) with a multileaf collimator (MLC) requires the conversion of a radiation fluence map into a leaf sequence file that controls the movement of the MLC during radiation delivery. It is imperative that the fluence map delivered using the leaf sequence file is as close as possible to the fluence map generated by the dose optimization algorithm, while satisfying hardware constraints of the delivery system. Optimization of the leaf sequencing algorithm has been the subject of several recent investigations. In this work, we present a systematic study of the optimization of leaf sequencing algorithms for segmental multileaf collimator beam delivery and provide rigorous mathematical proofs of optimized leaf sequence settings in terms of monitor unit (MU) efficiency under most common leaf movement constraints that include minimum leaf separation constraint and leaf interdigitation constraint. Our analytical analysis shows that leaf sequencing based on unidirectional movement of the MLC leaves is as MU efficient as bidirectional movement of the MLC leaves

  11. Leaf sequencing algorithms for segmented multileaf collimation

    Energy Technology Data Exchange (ETDEWEB)

    Kamath, Srijit [Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL (United States); Sahni, Sartaj [Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL (United States); Li, Jonathan [Department of Radiation Oncology, University of Florida, Gainesville, FL (United States); Palta, Jatinder [Department of Radiation Oncology, University of Florida, Gainesville, FL (United States); Ranka, Sanjay [Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL (United States)

    2003-02-07

    The delivery of intensity-modulated radiation therapy (IMRT) with a multileaf collimator (MLC) requires the conversion of a radiation fluence map into a leaf sequence file that controls the movement of the MLC during radiation delivery. It is imperative that the fluence map delivered using the leaf sequence file is as close as possible to the fluence map generated by the dose optimization algorithm, while satisfying hardware constraints of the delivery system. Optimization of the leaf sequencing algorithm has been the subject of several recent investigations. In this work, we present a systematic study of the optimization of leaf sequencing algorithms for segmental multileaf collimator beam delivery and provide rigorous mathematical proofs of optimized leaf sequence settings in terms of monitor unit (MU) efficiency under most common leaf movement constraints that include minimum leaf separation constraint and leaf interdigitation constraint. Our analytical analysis shows that leaf sequencing based on unidirectional movement of the MLC leaves is as MU efficient as bidirectional movement of the MLC leaves.

  12. Two Inexpensive and Non-destructive Techniques to Correct for Smaller-Than-Gasket Leaf Area in Gas Exchange Measurements

    Directory of Open Access Journals (Sweden)

    Andreas M. Savvides

    2018-04-01

    Full Text Available The development of technology, like the widely-used off-the-shelf portable photosynthesis systems, for the quantification of leaf gas exchange rates and chlorophyll fluorescence offered photosynthesis research a massive boost. Gas exchange parameters in such photosynthesis systems are calculated as gas exchange rates per unit leaf area. In small chambers (<10 cm2, the leaf area used by the system for these calculations is actually the internal gasket area (AG, provided that the leaf covers the entire AG. In this study, we present two inexpensive and non-destructive techniques that can be used to easily quantify the enclosed leaf area (AL of plant species with leaves of surface area much smaller than the AG, such as that of cereal crops. The AL of the cereal crop species studied has been measured using a standard image-based approach (iAL and estimated using a leaf width-based approach (wAL. iAL and wAL did not show any significant differences between them in maize, barley, hard and soft wheat. Similar results were obtained when the wAL was tested in comparison with iAL in different positions along the leaf in all species studied. The quantification of AL and the subsequent correction of leaf gas exchange parameters for AL provided a precise quantification of net photosynthesis and stomatal conductance especially with decreasing AL. This study provides two practical, inexpensive and non-destructive solutions to researchers dealing with photosynthesis measurements on small-leaf plant species. The image-based technique can be widely used for quantifying AL in many plant species despite their leaf shape. The leaf width-based technique can be securely used for quantifying AL in cereal crop species such as maize, wheat and barley along the leaf. Both techniques can be used for a wide range of gasket shapes and sizes with minor technique-specific adjustments.

  13. Inhibition of mild steel corrosion using Jatropha Curcas leaf extract

    Directory of Open Access Journals (Sweden)

    OLORUNFEMI MICHAEL AJAYI

    2014-05-01

    Full Text Available Jatropha Curcas leaf was investigated as a green inhibitor on the degradation of mild steel in 4 M HCl and 4 M H2SO4 aqueous solutions using gasometric technique. Mild steel coupons of dimension 2 × 1.5 cm were immersed in test solutions of uninhibited acid and also those with extract concentrations of 4 ml, 6 ml, 8 ml and 10 ml at 30 oC, for up to 30 minutes. The results showed that as the concentration of the extract increases, there was reduction in the corrosion rate. As the extract concentration increased from 4 ml to 10 ml at 30 minutes exposure, the volume of hydrogen gas evolved decreased from 19.1 cm3 to 11.2 cm3 in H2SO4 medium, while it reduced to 5 cm3 from 9 cm3 in HCl medium. Also, the metal surface-phytoconstituent interaction mechanism showed that 6 minutes is the best exposure time for the adsorption of the extract in both acidic media. The Jatropha Curcas leaf extract was adsorbed on the mild steel surface to inhibit corrosion, while the experimental data obtained at 30 minutes exposure in both acidic media were well fitted with the Langmuir adsorption isotherm. Hence, Jatropha Curcas leaf extract is a good and safe inhibitor in both acidic solutions.

  14. Effect of Addition of Moringa Leaf By-Product (Leaf-Waste) on ...

    African Journals Online (AJOL)

    The effects of incorporation of Moringa leaf fibre (a by-product of leaf processing which contains 24% Crude Fibre by dry weight at 0, 5 and 10 % substitution of wheat flour in cookies was investigated. Three products containing wheat flour: Moringa leaf fibre ratios of 100:0, 95:5, and 90:10 respectively were prepared, and a ...

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

    NARCIS (Netherlands)

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

    2017-01-01

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

  16. Leaf size and leaf display of thirty-eight tropical tree species

    NARCIS (Netherlands)

    Poorter, L.; Rozendaal, D.M.A.

    2008-01-01

    Trees forage for light through optimal leaf display. Effective leaf display is determined by metamer traits (i.e., the internode, petiole, and corresponding leaf), and thus these traits strongly co-determine carbon gain and as a result competitive advantage in a light-limited environment. We

  17. Host Phenology and Leaf Effects on Susceptibility of California Bay Laurel to Phytophthora ramorum.

    Science.gov (United States)

    Johnston, Steven F; Cohen, Michael F; Torok, Tamas; Meentemeyer, Ross K; Rank, Nathan E

    2016-01-01

    Spread of the plant pathogen Phytophthora ramorum, causal agent of the forest disease sudden oak death, is driven by a few competent hosts that support spore production from foliar lesions. The relationship between traits of a principal foliar host, California bay laurel (Umbellularia californica), and susceptibility to P. ramorum infection were investigated with multiple P. ramorum isolates and leaves collected from multiple trees in leaf-droplet assays. We examined whether susceptibility varies with season, leaf age, or inoculum position. Bay laurel susceptibility was highest during spring and summer and lowest in winter. Older leaves (>1 year) were more susceptible than younger ones (8 to 11 months). Susceptibility was greater at leaf tips and edges than the middle of the leaf. Leaf surfaces wiped with 70% ethanol were more susceptible to P. ramorum infection than untreated leaf surfaces. Our results indicate that seasonal changes in susceptibility of U. californica significantly influence P. ramorum infection levels. Thus, in addition to environmental variables such as temperature and moisture, variability in host plant susceptibility contributes to disease establishment of P. ramorum.

  18. Theoretical analysis of radiation field penumbra from a multi leaf collimator

    International Nuclear Information System (INIS)

    Li Shidong; Boyer, Arthur; Findley, David; Mok, Ed

    1996-01-01

    Purpose/Objective: Analysis and measurement of the difference between the light field and the radiation field of the multi leaf collimator (MLC) leaves that are constructed with curved ends. Material and Methods: A Varian MLC with curved leaf ends was installed on a Clinac 2300 C/D. The leaves were 6.13 cm deep (dimension in beam direction) and were located 53.9 cm from the x-ray target. The leaf ends had an 8 cm radius of curvature. A relation was derived using three dimensional geometry predicting the location of the light field edge relative to the geometric projection of the tip of the curved leaf end. This is a nonlinear relationship because the shadow of the leaf is generated by different points along the leaf end surface as the leaf moves across the field. The theoretical edge of the radiation fluence for a point source was taken to be located along the projection of a chord whose length was 1 Half-Value Thickness (HVT). The chords having projection points across the light field edge were computed using an analytical solution. The radiation transmission through the leaf end was then estimated. The HVT used for tungsten alloy, the leaf material, was 0.87 cm and 0.94 cm for the 6 MV and 15 MV photon beams, respectively. The location of the projection of the 1 HVT chord at a distance of 100 cm from x-ray target was also a nonlinear function of the projection of the leaf tip. Results: The displacement of the light field edge relative to the projection of the leaf tip varies from 0 mm when the leaf tip projects to the central axis, to approximately 3.2 mm for a 20 cm half-field width. The light field edge was always displaced into the unblocked area. The displacement of the projection of the 1 HVT chord relative to the projection of the leaf tip varies from 0.3 mm on the central axis to 3.0 mm for a 20 cm half-field width. The projection of 1 HVT chord was deviated from the light field edge by only 0.3 mm which would be slightly increased to 0.4 mm on decreasing

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

    Science.gov (United States)

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

    2002-08-01

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

  20. Relation between Silver Nanoparticle Formation Rate and Antioxidant Capacity of Aqueous Plant Leaf Extracts

    Directory of Open Access Journals (Sweden)

    Azat Akbal

    2016-01-01

    Full Text Available Correlation between the antioxidant capacity and silver nanoparticle formation rates of pomegranate (Punica granatum, quince (Cydonia oblonga, chestnut (Castanea sativa, fig (Ficus carica, walnut (Juglans cinerea, black mulberry (Morus nigra, and white mulberry (Morus alba leaf extracts is investigated at a fixed illumination. Silver nanoparticles formed in all plant leaf extracts possess round shapes with average particle size of 15 to 25 nm, whereas corresponding surface plasmon resonance peak wavelengths vary between 422 nm and 451 nm. Cupric reducing antioxidant capacity technique is used as a reference method to determine total antioxidant capacity of the plant leaf extracts. Integrated absorbance over the plasmon resonance peaks exhibits better linear relation with antioxidant capacities of various plant leaf extracts compared to peak absorbance values, with correlation coefficient values of 0.9333 and 0.7221, respectively.

  1. Abiotic and biotic determinants of leaf carbon exchange capacity from tropical to high boreal biomes

    Science.gov (United States)

    Smith, N. G.; Dukes, J. S.

    2016-12-01

    Photosynthesis and respiration on land represent the two largest fluxes of carbon dioxide between the atmosphere and the Earth's surface. As such, the Earth System Models that are used to project climate change are high sensitive to these processes. Studies have found that much of this uncertainty is due to the formulation and parameterization of plant photosynthetic and respiratory capacity. Here, we quantified the abiotic and biotic factors that determine photosynthetic and respiratory capacity at large spatial scales. Specifically, we measured the maximum rate of Rubisco carboxylation (Vcmax), the maximum rate of Ribulose-1,5-bisphosphate regeneration (Jmax), and leaf dark respiration (Rd) in >600 individuals of 98 plant species from the tropical to high boreal biomes of Northern and Central America. We also measured a bevy of covariates including plant functional type, leaf nitrogen content, short- and long-term climate, leaf water potential, plant size, and leaf mass per area. We found that plant functional type and leaf nitrogen content were the primary determinants of Vcmax, Jmax, and Rd. Mean annual temperature and mean annual precipitation were not significant predictors of these rates. However, short-term climatic variables, specifically soil moisture and air temperature over the previous 25 days, were significant predictors and indicated that heat and soil moisture deficits combine to reduce photosynthetic capacity and increase respiratory capacity. Finally, these data were used as a model benchmarking tool for the Community Land Model version 4.5 (CLM 4.5). The benchmarking analyses determined errors in the leaf nitrogen allocation scheme of CLM 4.5. Under high leaf nitrogen levels within a plant type the model overestimated Vcmax and Jmax. This result suggested that plants were altering their nitrogen allocation patterns when leaf nitrogen levels were high, an effect that was not being captured by the model. These data, taken with models in mind

  2. Cross-scale modelling of transpiration from stomata via the leaf boundary layer

    Science.gov (United States)

    Defraeye, Thijs; Derome, Dominique; Verboven, Pieter; Carmeliet, Jan; Nicolai, Bart

    2014-01-01

    Background and Aims Leaf transpiration is a key parameter for understanding land surface–climate interactions, plant stress and plant structure–function relationships. Transpiration takes place at the microscale level, namely via stomata that are distributed discretely over the leaf surface with a very low surface coverage (approx. 0·2–5 %). The present study aims to shed more light on the dependency of the leaf boundary-layer conductance (BLC) on stomatal surface coverage and air speed. Methods An innovative three-dimensional cross-scale modelling approach was applied to investigate convective mass transport from leaves, using computational fluid dynamics. The gap between stomatal and leaf scale was bridged by including all these scales in the same computational model (10−5–10−1 m), which implies explicitly modelling individual stomata. Key Results BLC was strongly dependent on stomatal surface coverage and air speed. Leaf BLC at low surface coverage ratios (CR), typical for stomata, was still relatively high, compared with BLC of a fully wet leaf (hypothetical CR of 100 %). Nevertheless, these conventional BLCs (CR of 100 %), as obtained from experiments or simulations on leaf models, were found to overpredict the convective exchange. In addition, small variations in stomatal CR were found to result in large variations in BLCs. Furthermore, stomata of a certain size exhibited a higher mass transfer rate at lower CRs. Conclusions The proposed cross-scale modelling approach allows us to increase our understanding of transpiration at the sub-leaf level as well as the boundary-layer microclimate in a way currently not feasible experimentally. The influence of stomatal size, aperture and surface density, and also flow-field parameters can be studied using the model, and prospects for further improvement of the model are presented. An important conclusion of the study is that existing measures of conductances (e.g. from artificial leaves) can be

  3. 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

  4. Estimation of leaf area in tropical maize

    NARCIS (Netherlands)

    Elings, A.

    2000-01-01

    Leaf area development of six tropical maize cultivars grown in 1995 and 1996 in several tropical environments in Mexico (both favourable and moisture-and N-limited) was observed and analysed. First, the validity of a bell-shaped curve describing the area of individual leaves as a function of leaf

  5. Chromosome-damaging effect of betel leaf.

    Science.gov (United States)

    Sadasivan, G; Rani, G; Kumari, C K

    1978-05-01

    The chewing of betel leaf with other ingredients is a widespread addiction in India. The chromosome damaging effect was studied in human leukocyte cultures. There was an increase in the frequency of chromatid aberrations when the leaf extract was added to cultures.

  6. ANXIOLYTIC ACTIVITY OF OCIMUM SANCTUM LEAF EXTRACT

    OpenAIRE

    Chattopadhyay, R.R.

    1994-01-01

    The anxiolytic activity of Ocimum sanctum leaf extract was studied in mice. O.sanctum leaf extract produced significant anxiolytic activity in plus – maze and open field behaviour test models. The effect was compared with diazepam, a standard antianxiety drug.

  7. 7 CFR 29.2530 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.2530 Section 29.2530 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2530 Leaf structure. The cell development of...

  8. 7 CFR 29.2278 - Leaf structure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.2278 Section 29.2278 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... structure. The cell development of a leaf as indicated by its porosity. (See chart, § 29.2351.) ...

  9. 7 CFR 29.2277 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.2277 Section 29.2277 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed tobacco and consists...

  10. 7 CFR 29.2529 - Leaf scrap.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.2529 Section 29.2529 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... tobacco. Leaf scrap results from handling unstemmed tobacco and consists of loose and tangled whole or...

  11. Caracterização morfoanatômica das folhas de Eremanthus erythropappus (DC. MacLeisch, Asteraceae Leaf morpho-anatomical characterization of Eremanthus erythropappus (DC. MacLeisch, Asteraceae

    Directory of Open Access Journals (Sweden)

    Rafael C. Dutra

    2010-12-01

    . The quantification of glandular trichomes on the adaxial surface of the epidermis was evaluated in young and mature leaves with camera lucida. The leaves are alternate or fasciculate and the blade has uniseriate epidermis coated with thin and smooth cuticle and dorsiventral mesophyll. There are predominantly anomocytic stomata on both surfaces, as well as glandular trichomes located in epidermal depressions. Various non-glandular trichomes are encountered on the abaxial surface. The palisade parenchyma consists of a single layer of cells and the parenchyma which is faced to the abaxial surface comprehends three to five layers of cells in compact arrangement. The young and mature leaves showed, respectively, 21.78±5.83 e 17.80±6.69 glandular trichomes on the adaxial side. The morpho-anatomical analysis of E. erythropappus leaves has proved to be a practical and rapid method for the identification and quality control of the vegetal species used for medical purposes.

  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

    NARCIS (Netherlands)

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

    2018-01-01

    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

  13. Easy Leaf Area: Automated digital image analysis for rapid and accurate measurement of leaf area.

    Science.gov (United States)

    Easlon, Hsien Ming; Bloom, Arnold J

    2014-07-01

    Measurement of leaf areas from digital photographs has traditionally required significant user input unless backgrounds are carefully masked. Easy Leaf Area was developed to batch process hundreds of Arabidopsis rosette images in minutes, removing background artifacts and saving results to a spreadsheet-ready CSV file. • Easy Leaf Area uses the color ratios of each pixel to distinguish leaves and calibration areas from their background and compares leaf pixel counts to a red calibration area to eliminate the need for camera distance calculations or manual ruler scale measurement that other software methods typically require. Leaf areas estimated by this software from images taken with a camera phone were more accurate than ImageJ estimates from flatbed scanner images. • Easy Leaf Area provides an easy-to-use method for rapid measurement of leaf area and nondestructive estimation of canopy area from digital images.

  14. Easy Leaf Area: Automated Digital Image Analysis for Rapid and Accurate Measurement of Leaf Area

    Directory of Open Access Journals (Sweden)

    Hsien Ming Easlon

    2014-07-01

    Full Text Available Premise of the study: Measurement of leaf areas from digital photographs has traditionally required significant user input unless backgrounds are carefully masked. Easy Leaf Area was developed to batch process hundreds of Arabidopsis rosette images in minutes, removing background artifacts and saving results to a spreadsheet-ready CSV file. Methods and Results: Easy Leaf Area uses the color ratios of each pixel to distinguish leaves and calibration areas from their background and compares leaf pixel counts to a red calibration area to eliminate the need for camera distance calculations or manual ruler scale measurement that other software methods typically require. Leaf areas estimated by this software from images taken with a camera phone were more accurate than ImageJ estimates from flatbed scanner images. Conclusions: Easy Leaf Area provides an easy-to-use method for rapid measurement of leaf area and nondestructive estimation of canopy area from digital images.

  15. Possible Roles of Strigolactones during Leaf Senescence

    Directory of Open Access Journals (Sweden)

    Yusuke Yamada

    2015-09-01

    Full Text Available Leaf senescence is a complicated developmental process that involves degenerative changes and nutrient recycling. The progress of leaf senescence is controlled by various environmental cues and plant hormones, including ethylene, jasmonic acid, salicylic acid, abscisic acid, cytokinins, and strigolactones. The production of strigolactones is induced in response to nitrogen and phosphorous deficiency. Strigolactones also accelerate leaf senescence and regulate shoot branching and root architecture. Leaf senescence is actively promoted in a nutrient-poor soil environment, and nutrients are transported from old leaves to young tissues and seeds. Strigolactones might act as important signals in response to nutrient levels in the rhizosphere. In this review, we discuss the possible roles of strigolactones during leaf senescence.

  16. Applicability of non-destructive substitutes for leaf area in different stands of Norway spruce (Picea abies L. Karst.) focusing on traditional forest crown measures

    Science.gov (United States)

    Laubhann, Daniel; Eckmüllner, Otto; Sterba, Hubert

    2010-01-01

    Since individual tree leaf area is an important measure for productivity as well as for site occupancy, it is of high interest in many studies about forest growth. The exact determination of leaf area is nearly impossible. Thus, a common way to get information about leaf area is to use substitutes. These substitutes are often variables which are collected in a destructive way which is not feasible for long term studies. Therefore, this study aimed at testing the applicability of using substitutes for leaf area which could be collected in a non-destructive way, namely crown surface area and crown projection area. In 8 stands of Norway spruce (Picea abies L. Karst.), divided into three age classes and two thinning treatments, a total of 156 trees were felled in order to test the relationship between leaf area and crown surface area and crown projection area, respectively. Individual tree leaf area of the felled sample trees was estimated by 3P-branch sampling with an accuracy of ±10%. Crown projection area and crown surface area were compared with other, more commonly used, but destructive predictors of leaf area, namely sapwood area at different heights on the bole. Our investigations confirmed findings of several studies that sapwood area is the most precise measure for leaf area because of the high correlation between sapwood area and the leaf area. But behind sapwood area at crown base and sapwood area at three tenth of the tree height the predictive ability of crown surface area was ranked third and even better than that of sapwood area at breast height (R2 = 0.656 compared with 0.600). Within the stands leaf area is proportional to crown surface area. Using the pooled data of all stands a mixed model approach showed that additionally to crown surface area dominant height and diameter at breast height (dbh) improved the leaf area estimates. Thus, taking dominant height and dbh into account, crown surface area can be recommended for estimating the leaf area of

  17. Applicability of non-destructive substitutes for leaf area in different stands of Norway spruce (Picea abies L. Karst.) focusing on traditional forest crown measures.

    Science.gov (United States)

    Laubhann, Daniel; Eckmüllner, Otto; Sterba, Hubert

    2010-09-30

    Since individual tree leaf area is an important measure for productivity as well as for site occupancy, it is of high interest in many studies about forest growth. The exact determination of leaf area is nearly impossible. Thus, a common way to get information about leaf area is to use substitutes. These substitutes are often variables which are collected in a destructive way which is not feasible for long term studies. Therefore, this study aimed at testing the applicability of using substitutes for leaf area which could be collected in a non-destructive way, namely crown surface area and crown projection area. In 8 stands of Norway spruce (Picea abies L. Karst.), divided into three age classes and two thinning treatments, a total of 156 trees were felled in order to test the relationship between leaf area and crown surface area and crown projection area, respectively. Individual tree leaf area of the felled sample trees was estimated by 3P-branch sampling with an accuracy of ±10%. Crown projection area and crown surface area were compared with other, more commonly used, but destructive predictors of leaf area, namely sapwood area at different heights on the bole. Our investigations confirmed findings of several studies that sapwood area is the most precise measure for leaf area because of the high correlation between sapwood area and the leaf area. But behind sapwood area at crown base and sapwood area at three tenth of the tree height the predictive ability of crown surface area was ranked third and even better than that of sapwood area at breast height (R(2) = 0.656 compared with 0.600). Within the stands leaf area is proportional to crown surface area. Using the pooled data of all stands a mixed model approach showed that additionally to crown surface area dominant height and diameter at breast height (dbh) improved the leaf area estimates. Thus, taking dominant height and dbh into account, crown surface area can be recommended for estimating the leaf area

  18. 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.

  19. Stomatal characterization of five species of the genus Vanilla.

    Directory of Open Access Journals (Sweden)

    Delfino Reyes-López

    2015-06-01

    Full Text Available The objective was to characterize the stomata of five species of vanilla. Throughout 2012, leaf samples of V. planifolia G. Jackson, V. pompona Schiede, V. indora Schiede, V. insignis Ames and V. odorota Presl were taken from the vanilla germplasm bank at the Benemérita Universidad Autónoma de Puebla. The stomata size was obtained considering their length and width, as well as the index and stomata number of the abaxial and adaxial leaf surfaces in a randomized complete block design with three replications. V. pompona Schiede and V. inodora Schiede showed the highest stomatal index with 8713 and 8246 stomata per mm2, respectively, followed by V. odorata Presl with 4412 stomata per mm2. V. insignis Ames and V. planifolia G. Jackson showed the lowest stomata index with 2968 and 1378 stomata per mm2, respectively, in the abaxial leaf surface, these differences were statistically significant (P≤0.05. According to the position of the leaf stomata, V. planifolia G. Jackson and V. inodora Schiede can be considered to be hypostomatics since they showed stomata only in the abaxial leaf surface. V. insignis Ames, V. inodora Schiede and V. odorata Presl. can be considered to be anfiestomatic because they showed stomata in both the abaxial and adaxial leaf surfaces. V. inodora Schiede had smaller stomata compared with the other species.That is an important feature to be included in the genetic improvement of the genus Vanilla, because due to climate change, temperature will increase and precipitation will decrease, so Vainilla will require more efficient genotypes for water use.

  20. Stomatal characterization of five species of the genus Vanilla

    International Nuclear Information System (INIS)

    Reyes-Lopez, Delfino; Quiroz-Valentin, Jonathan; Kelso-Bucio, Henry Arturo; Huerta-Lara, Manuel; Avendano-Arrazate, Carlos Hugo; Lobato-Ortiz, Ricardo

    2015-01-01

    The stomata of five species of vanilla were characterized. Throughout 2012, leaf samples of V. planifolia G. Jackson, V. pompona Schiede, V. inodora Schiede, V. insignis Ames and V. odorota Presl were taken from the vanilla germplasm bank at the Benemerita Universidad Autonoma de Puebla, throughout 2012. The stomata size was obtained considering their length and width, as well as the index and stomata number of the abaxial and adaxial leaf surfaces in a randomized complete block design with three replications. The highest stomatal index with 8713 and 8246 stomata per mm"2, was showed in V. pompona Schiede an V. inodora Schiede respectively, followed by V. odorata Presl with 4412 stomata per mm"2. The lowest stomata index with 2968 and 1378 stomata per mm"2, was showed by V. insignis Ames and V. planifolia G. Jackson respectively, in the abaxial leaf surface, these differences were statistically significant (p≤0,05). According to the position of the leaf stomata, V. planifolia G. Jackson and V. inodora Schiede can be considered to be hypostomatics since they showed stomata only in the abaxial leaf surface. V. insignis Ames, V. inodora Schiede and V. odorata Presl. can be considered to be anfiestomatic because they showed stomata in both the abaxial and adaxial leaf surfaces. V. inodora Schiede has had smaller stomata compared with the other species. That is an important feature to be included in the genetic improvement of the genus Vanilla, because due to climate change, temperature will increase and precipitation will decrease, so Vainilla will require more efficient genotypes for water use. (author) [es

  1. Detritivores enhance the mobilization of {sup 137}Cs from leaf-litter

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Masashi; Suzuki, Takahiro [Community Ecology Lab., Biology Course, Faculty of Science, Chiba University, Chiba, 263-8522 (Japan); Ishii, Nobuyoshi [National Institute of Radiological Sciences, Chiba, 263-8555 (Japan); Ohte, Nobuhito [Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657 (Japan)

    2014-07-01

    A large amount of radioactive material was released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident after the disastrous earthquake and subsequent tsunami of March 2011. Since most of the Japanese land area is covered by forest ecosystems, {sup 137}Cs was mostly deposited and accumulated on the land surface of forest. The fate of radioactive materials accumulated on the leaf litters should be conscientiously monitored to understand the future distribution and the spread to the surrounding landscapes. Because the accident took place on 11 March 2011, just before the bud-break of deciduous trees, the {sup 137}Cs are highly accumulated on the surface of leaf litter on the forest floor. This accumulated {sup 137}Cs had transferred to higher trophic organisms mainly through the detritus food chain. However, on the litter surface, {sup 137}Cs considered to be strongly and immediately fixed and highly immobilized. Decomposition processes in the forest floor can re-mobilise the nutritional elements which are contained within detritus and make them available for the organisms. In the present study, the feeding effect of detritivore soil arthropods on the mobilization of {sup 137}Cs from leaf litter was experimentally examined. Furthermore, the effect of detritivores on the plant uptake of {sup 137}Cs was examined by small-scale nursery experiment. Decomposition experiment in the small microcosms was performed using a larvae of Trypoxylus dichotomus, whichis a detritivores feeding on dead plant materials such as wood debris and leaf litters. Contaminated leaf litters were collected in a forest of the Kami-Oguni River catchment in the northern part of Fukushima Prefecture. The leaf litters at A0 layers which are highly contaminated by {sup 137}Cs were utilized for the experiment. The contaminated leaf litter was fed to the larvae for ten days. The litter with larvae excreta was washed by 2 M KCl and deionized water. The {sup 137}Cs concentration was measured

  2. Leaf Structure and Taxonomy of Petunia and Calibrachoa (Solanaceae

    Directory of Open Access Journals (Sweden)

    Claudia dos Reis

    2002-03-01

    Full Text Available We studied the leaf anatomy of sixteen species of Calibrachoa and eight species of Petunia. In Calibrachoa leaves, the vascular bundles sheath (endodermis was formed by parenchymatous developed cells, different from those of the mesophyll. In Petunia, this sheath did not show a marked morphological differentiation. The Calibrachoa leaves could be separated according to the type of leaf margins, the distribution of the stomata on leaf surfaces, the organization of the mesophyll and the morphology of the trichomes. Based on these results, an indented dichotomous identification key was elaborated for the species of the genus Calibrachoa.Foram estudados, sob o ponto de vista anatômico, os limbos foliares de dezesseis espécies de Calibrachoa Llav. & Lex. e de oito espécies de Petunia Juss. (Solanaceae. Em Calibrachoa, a bainha que envolve os feixes vasculares (endoderme é formada por células desenvolvidas e distintas das do mesofilo. Em Petunia, esta bainha não apresenta diferenciação morfológica marcante. As folhas das espécies de Calibrachoa foram separadas entre si levando-se em conta a distribuição dos estômatos nas faces foliares, a organização do mesofilo, o tipo de bordo e a morfologia dos tricomas. Com base nesses resultados, foi elaborada uma chave dicotômica indentada de identificação para as espécies do gênero Calibrachoa.

  3. Titan LEAF: A Sky Rover Granting Targeted Access to Titan's Lakes and Plains

    Science.gov (United States)

    Ross, Floyd; Lee, Greg; Sokol, Daniel; Goldman, Benjamin; Bolisay, Linden

    2016-10-01

    Northrop Grumman, in collaboration with L'Garde Inc. and Global Aerospace Corporation (GAC), has been developing the Titan Lifting Entry Atmospheric Flight (T-LEAF) sky rover to roam the atmosphere and observe at close quarters the lakes and plains of Titan. T-LEAF also supports surface exploration and science by providing precision delivery of in situ instruments to the surface.T-LEAF is a maneuverable, buoyant air vehicle. Its aerodynamic shape provides its maneuverability, and its internal helium envelope reduces propulsion power requirements and also the risk of crashing. Because of these features, T-LEAF is not restricted to following prevailing wind patterns. This freedom of mobility allows it be commanded to follow the shorelines of Titan's methane lakes, for example, or to target very specific surface locations.T-LEAF utilizes a variable power propulsion system, from high power at ~200W to low power at ~50W. High power mode uses the propellers and control surfaces for additional mobility and maneuverability. It also allows the vehicle to hover over specific locations for long duration surface observations. Low power mode utilizes GAC's Titan Winged Aerobot (TWA) concept, currently being developed with NASA funding, which achieves guided flight without the use of propellers or control surfaces. Although slower than high powered flight, this mode grants increased power to science instruments while still maintaining control over direction of travel.Additionally, T-LEAF is its own entry vehicle, with its leading edges protected by flexible thermal protection system (f-TPS) materials already being tested by NASA's Hypersonic Inflatable Aerodynamic Decelerator (HIAD) group. This f-TPS technology allows T-LEAF to inflate in space, like HIAD, and then enter the atmosphere fully deployed. This approach accommodates entry velocities from as low as ~1.8 km/s if entering from Titan orbit, up to ~6 km/s if entering directly from Saturn orbit, like the Huygens probe

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  5. Can biomass responses to warming at plant to ecosystem levels be predicted by leaf-level responses?

    Science.gov (United States)

    Xia, J.; Shao, J.; Zhou, X.; Yan, W.; Lu, M.

    2015-12-01

    Global warming has the profound impacts on terrestrial C processes from leaf to ecosystem scales, potentially feeding back to climate dynamics. Although numerous studies had investigated the effects of warming on C processes from leaf to plant and ecosystem levels, how leaf-level responses to warming scale up to biomass responses at plant, population, and community levels are largely unknown. In this study, we compiled a dataset from 468 papers at 300 experimental sites and synthesized the warming effects on leaf-level parameters, and plant, population and ecosystem biomass. Our results showed that responses of plant biomass to warming mainly resulted from the changed leaf area rather than the altered photosynthetic capacity. The response of ecosystem biomass to warming was weaker than those of leaf area and plant biomass. However, the scaling functions from responses of leaf area to plant biomass to warming were different in diverse forest types, but functions were similar in non-forested biomes. In addition, it is challenging to scale the biomass responses from plant up to ecosystem. These results indicated that leaf area might be the appropriate index for plant biomass response to warming, and the interspecific competition might hamper the scaling of the warming effects on plant and ecosystem levels, suggesting that the acclimation capacity of plant community should be incorporated into land surface models to improve the prediction of climate-C cycle feedback.

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

    Directory of Open Access Journals (Sweden)

    BRUNO H.P. ROSADO

    2013-09-01

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

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

    Science.gov (United States)

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

    2013-09-01

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

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

    Science.gov (United States)

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

    2010-11-01

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

  9. Characterization and pathogenicity of Fusarium species associated with leaf spot of mango (Mangifera indica L.).

    Science.gov (United States)

    Omar, Nurul Husna; Mohd, Masratulhawa; Mohamed Nor, Nik Mohd Izham; Zakaria, Latiffah

    2018-01-01

    Leaf spot diseases are mainly caused by fungi including Fusarium. In the present study several species of Fusarium were isolated from the leaf spot lesion of mango (Mangifera indica L.) Based on morphological characteristics, TEF-1α sequences and phylogenetic analysis, five species were identified as F. proliferatum, F. semitectum, F. mangiferae, F. solani and F. chlamydosporum. Pathogenicity test indicated that representative isolates of F. proliferatum, F. semitectum and F. chlamydosporum were pathogenic on mango leaves causing leaf spot with low to moderate virulence. Nevertheless, abundance of spots on the leaf can disrupt photosynthesis which in turn reduced growth, and lead to susceptibility to infection by opportunistic pathogens due to weakening of the plant. Fusarium solani and F. mangiferae were non-pathogenic and it is possible that both species are saprophyte which associated with nutrient availability on the surface of the leaf through decaying leave tissues. The occurrence of Fusarium spp. on the leaf spot lesion and the effect from the disease needs to be considered when developing disease management method of mango cultivation as numerous spot on the leaves could effect the photosynthesis process and finally giving low yield and less quality of mango. Copyright © 2017. Published by Elsevier Ltd.

  10. 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.

  11. Leaf Characteristics and Photosynthetic Performance of Floating, Emergent and Terrestrial Leaves of Marsilea quadrifolia

    Directory of Open Access Journals (Sweden)

    Chia-Hong Lin

    2007-09-01

    Full Text Available Individuals of Marsilea quadrifolia, an amphibious fern, experiencing extreme variation in environment develop heterophyll. In this study, we compared stomatal and trichome density on upper and lower surfaces, leaf and petiole area mass ratio, spectral properties and photosynthetic performance of floating, emergent and terrestrial leaves of M. quadrifolia, to explore the ecological advantages of producing different leaf types. Morphological measurement reveals that these three types of leaf display highly differences in stomatal density on lower epidermis, trichome density on both surfaces and petiole dry mass per length, and reflectance coefficient between 500 and 650 nm. In contrast, no significant difference was found in the PSII electron transport rate of the three types of leaves. The analysis of stable carbon isotope ratio of the three types of leaves indicates that they all use C3 photosynthetic pathway.

  12. Evaluation of Methane from Sisal Leaf Residue and Palash Leaf Litter

    Science.gov (United States)

    Arisutha, S.; Baredar, P.; Deshpande, D. M.; Suresh, S.

    2014-12-01

    The aim of this study is to evaluate methane production from sisal leaf residue and palash leaf litter mixed with different bulky materials such as vegetable market waste, hostel kitchen waste and digested biogas slurry in a laboratory scale anaerobic reactor. The mixture was prepared with 1:1 proportion. Maximum methane content of 320 ml/day was observed in the case of sisal leaf residue mixed with vegetable market waste as the feed. Methane content was minimum (47 ml/day), when palash leaf litter was used as feed. This was due to the increased content of lignin and polyphenol in the feedstock which were of complex structure and did not get degraded directly by microorganisms. Sisal leaf residue mixtures also showed highest content of volatile fatty acids (VFAs) as compared to palash leaf litter mixtures. It was observed that VFA concentration in the digester first increased, reached maximum (when pH was minimum) and then decreased.

  13. Leaf structural traits of tropical woody species resistant to cement dust.

    Science.gov (United States)

    Siqueira-Silva, Advanio Inácio; Pereira, Eduardo Gusmão; Modolo, Luzia Valentina; Paiva, Elder Antonio Sousa

    2016-08-01

    Cement industries located nearby limestone outcrops in Brazil have contributed to the coating of cement dust over native plant species. However, little is known about the extent of the response of tropical woody plants to such environmental pollutant particularly during the first stages of plant development and establishment. This work focused on the investigation of possible alterations in leaf structural and ultrastructural traits of 5-month-old Guazuma ulmifolia Lam. (Malvaceae), 6-month-old Myracrodruon urundeuva Allemão (Anacardiaceae), and 9-month-old Trichilia hirta L. (Meliaceae) challenged superficially with cement dust during new leaf development. Leaf surface of plants, the soil or both (leaf plus soil), were treated (or not) for 60 days, under controlled conditions, with cement dust at 2.5 or 5.0 mg cm(-2). After exposure, no significant structural changes were observed in plant leaves. Also, no plant death was recorded by the end of the experiment. There was also some evidence of localized leaf necrosis in G. ulmifolia and T. hirta, leaf curling in M. urundeuva and T. hirta, and bulges formation on epidermal surface of T. hirta, after cement dust contact with plant shoots. All species studied exhibited stomata obliteration while T. hirta, in particular, presented early leaf abscission, changes in cellular relief, and organization and content of midrib cells. No significant ultrastructural alterations were detected under the experimental conditions studied. Indeed, mesophyll cells presented plastids with intact membrane systems. The high plant survival rates, together with mild morphoanatomic traits alterations in leaves, indicate that G. ulmifolia is more resistant to cement dust pollutant, followed by M. urundeuva and T. hirta. Thus, the three plant species are promising for being used to revegetate areas impacted by cement industries activities.

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

    Directory of Open Access Journals (Sweden)

    Ludger Grünhage

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

  15. 7 CFR 30.31 - Classification of leaf tobacco.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Classification of leaf tobacco. 30.31 Section 30.31... REGULATIONS TOBACCO STOCKS AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of Grades § 30.31 Classification of leaf tobacco. For the purpose of this classification leaf tobacco shall...

  16. What Is a Leaf? An Online Tutorial and Tests

    Science.gov (United States)

    Burrows, Geoffrey

    2008-01-01

    A leaf is a fundamental unit in botany and understanding what constitutes a leaf is fundamental to many plant science activities. My observations and subsequent testing indicated that many students could not confidently and consistently recognise a leaf from a leaflet, or recognise basic leaf arrangements and the various types of compound or…

  17. 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 ...

  18. PHARMACOGNOSITIC STUDIES OF THE LEAF AND STEMBARK ...

    African Journals Online (AJOL)

    PHARMACOGNOSITIC STUDIES OF THE LEAF AND STEMBARK OF STEGANOTAENIA ARALIACEAE HOCHST. Z Mohammed, M Shok, EM Abdurahman. Abstract. Microscopical investigation of the powdered leaves and stembark of Steganotaenia araliaceae (family Umbelliferae) shows the presence of anisocytic ...

  19. 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.

  20. Leaf functional response to increasing atmospheric CO(2) concentrations over the last century in two northern Amazonian tree species: a historical δ(13) C and δ(18) O approach using herbarium samples.

    Science.gov (United States)

    Bonal, Damien; Ponton, Stéphane; Le Thiec, Didier; Richard, Béatrice; Ningre, Nathalie; Hérault, Bruno; Ogée, Jérôme; Gonzalez, Sophie; Pignal, Marc; Sabatier, Daniel; Guehl, Jean-Marc

    2011-08-01

    We assessed the extent of recent environmental changes on leaf morphological (stomatal density, stomatal surface, leaf mass per unit area) and physiological traits (carbon isotope composition, δ(13)C(leaf) , and discrimination, Δ(13)C(leaf) , oxygen isotope composition, δ(18)O(leaf) ) of two tropical rainforest species (Dicorynia guianensis; Humiria balsamifera) that are abundant in the Guiana shield (Northern Amazonia). Leaf samples were collected in different international herbariums to cover a 200 year time-period (1790-2004) and the whole Guiana shield. Using models describing carbon and oxygen isotope fractionations during photosynthesis, different scenarios of change in intercellular CO(2) concentrations inside the leaf (C(i)), stomatal conductance (g), and photosynthesis (A) were tested in order to understand leaf physiological response to increasing air CO(2) concentrations (C(a)). Our results confirmed that both species displayed physiological response to changing C(a) . For both species, we observed a decrease of about 1.7‰ in δ(13)C(leaf) since 1950, without significant change in Δ(13)C(leaf) and leaf morphological traits. Furthermore, there was no clear change in δ(18)O(leaf) for Humiria over this period. Our simulation approach revealed that an increase in A, rather than a decrease in g, explained the observed trends for these tropical rainforest species, allowing them to maintain a constant ratio of C(i)/C(a) . © 2011 Blackwell Publishing Ltd.

  1. Why Does Not the Leaf Weight-Area Allometry of Bamboos Follow the 3/2-Power Law?

    Directory of Open Access Journals (Sweden)

    Shuyan Lin

    2018-05-01

    Full Text Available The principle of similarity (Thompson, 1917 states that the weight of an organism follows the 3/2-power law of its surface area and is proportional to its volume on the condition that the density is constant. However, the allometric relationship between leaf weight and leaf area has been reported to greatly deviate from the 3/2-power law, with the irregularity of leaf density largely ignored for explaining this deviation. Here, we choose 11 bamboo species to explore the allometric relationships among leaf area (A, density (ρ, length (L, thickness (T, and weight (W. Because the edge of a bamboo leaf follows a simplified two-parameter Gielis equation, we could show that A ∝ L2 and that A ∝ T2. This then allowed us to derive the density-thickness allometry ρ ∝ Tb and the weight-area allometry W ∝ A(b+3/2 ≈ A9/8, where b approximates −3/4. Leaf density is strikingly negatively associated with leaf thickness, and it is this inverse relationship that results in the weight-area allometry to deviate from the 3/2-power law. In conclusion, although plants are prone to invest less dry mass and thus produce thinner leaves when the leaf area is sufficient for photosynthesis, such leaf thinning needs to be accompanied with elevated density to ensure structural stability. The findings provide the insights on the evolutionary clue about the biomass investment and output of photosynthetic organs of plants. Because of the importance of leaves, plants could have enhanced the ratio of dry material per unit area of leaf in order to increase the efficiency of photosynthesis, relative the other parts of plants. Although the conclusion is drawn only based on 11 bamboo species, it should also be applicable to the other plants, especially considering previous works on the exponent of the weight-area relationship being less than 3/2 in plants.

  2. Non-linear direct effects of acid rain on leaf photosynthetic rate of terrestrial plants

    NARCIS (Netherlands)

    Dong, Dan; Du, Enzai; Sun, Zhengzhong; Zeng, Xuetong; Vries, de Wim

    2017-01-01

    Anthropogenic emissions of acid precursors have enhanced global occurrence of acid rain, especially in East Asia. Acid rain directly suppresses leaf function by eroding surface waxes and cuticle and leaching base cations from mesophyll cells, while the simultaneous foliar uptake of nitrates in

  3. Soil fauna and leaf species, but not species diversity, affect initial soil erosion in a subtropical forest plantation

    Science.gov (United States)

    Seitz, Steffen; Goebes, Philipp; Assmann, Thorsten; Schuldt, Andreas; Scholten, Thomas

    2017-04-01

    litter layer was influenced by the presence (or absence) of soil meso- and macrofauna. Fauna presence increased soil erosion rates significantly by 58 %. It was assumed that this faunal effect arose from arthropods loosening and processing the soil surface as well as fragmenting and decomposing the protecting leaf litter covers. Thus, effects of this fauna group on sediment discharge have to be considered in soil erosion experiments.

  4. Leaf Area Estimation Models for Ginger ( Zingibere officinale Rosc ...

    African Journals Online (AJOL)

    The study was carried out to develop leaf area estimation models for three cultivars (37/79, 38/79 and 180/73) and four accessions (29/86, 30/86, 47/86 and 52/86) of ginger. Significant variations were observed among the tested genotypes in leaf length (L), leaf width (W) and actual leaf area (ALA). Leaf area was highly ...

  5. Variability in leaf surface features and water efficiency utilisation in ...

    African Journals Online (AJOL)

    The C4 form was found to be more efficient with respect to water utilization efficiency. Keywords: alloteropsis semialata; botany; characteristics; distribution; grasses; leaves; photosynthetic rate; plant physiology; south africa; stomatal resistance; transpiration rate; transvaal highveld; water use efficiency; water utilization ...

  6. Variação do número de estômatos e micropêlos em Paspalum vaginatum Sw: em relação às condições abióticas numa marisma do estuário da Lagoa dos Patos, RS-Brasil Variation in the number of stomata and microhairs of Paspalum vaginatum Sw: en relation to abiotic conditions in a breakwater in the Lagoa dos Patos estuary, RS-Brazil

    Directory of Open Access Journals (Sweden)

    Eleci de Oliveria Bastos

    1992-12-01

    Full Text Available Paspalum vaginatum Sw., gramínea perene, estolonífera, com folhas anfistomáticas e pequenas é característica de pântanos salgados, crescendo em condições estressantes na marisma da lagoa dos Patos, molhe oeste da Barra do Rio Grande, RS. Foram feitas contagens mensais de estômatos e micropêlos nas superfícies adaxial e abaxial das lâminas e relacionadas às características abióticas do ambiente. O número de micropêlos da superfície foliar abaxial variou significativamente e diretamente com a temperatura da água intersticial junto às rizosferas. Estes, porém, não mantiveram correlação com a salinidade intersticial. Os resultados sugerem que a espécie seja uma halófita facultativa. O número de estômatos da superfície abaxial manteve um relacionamento inverso com a pluviosidade. Paspalum vaginatum, apresenta-se como uma espécie com características xeromórficas.Paspalum vaginatum Sw., a perennial, stoloniferous grass with small leaves presenting stomata on both epidermises is characteristic of salt marshes, growing under stressful conditions near the west breakwater of the Rio Grande outlet, Lagoa dos Patos, Rio Grande do Sul, Brazil. Monthly counts of stomata and microhairs on the adaxial and abaxial surfaces were related to the abiotic characteristics of the enviroment. The number of microhairs of the abaxial leaf surface varied significantly and directly with interstitial water temperature close to the rhyzosphere. However, these counts did not correlate with the interstitial salinity. The results suggest that the species is a facultative halophyte. Stomata counts of the abaxial surface showed an inverse relation to precipitation. Paspalum vaginatum appears to be a species with xeromorphic characteristics.

  7. Influence of Environmental Pollution on Leaf Properties of Urban Plane Trees, Platanus orientalis L.

    Science.gov (United States)

    Pourkhabbaz, Alireza; Rastin, Nayerah; Olbrich, Andrea; Langenfeld-Heyser, Rosemarie

    2010-01-01

    To investigate whether leaves of plane trees (Platanus orientalis) are damaged by traffic pollution, trees from a megacity (Mashhad, Iran) and a rural area were investigated. Soil and air from the urban centre showed enrichment of several toxic elements, but only lead was enriched in leaves. Leaf size and stomata density were lower at the urban site. At the urban site leaf surfaces were heavily loaded by dust particles but the stomata were not occluded; the cuticle was thinner; other anatomical properties were unaffected suggesting that plane trees can cope with traffic exhaust in megacities. PMID:20577871

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

    Science.gov (United States)

    2007-01-01

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

  9. Estimating leaf area and leaf biomass of open-grown deciduous urban trees

    Science.gov (United States)

    David J. Nowak

    1996-01-01

    Logarithmic regression equations were developed to predict leaf area and leaf biomass for open-grown deciduous urban trees based on stem diameter and crown parameters. Equations based on crown parameters produced more reliable estimates. The equations can be used to help quantify forest structure and functions, particularly in urbanizing and urban/suburban areas.

  10. NARROW LEAF 7 controls leaf shape mediated by auxin in rice

    NARCIS (Netherlands)

    Fujino, Kenji; Matsuda, Yasuyuki; Ozawa, Kenjirou; Nishimura, Takeshi; Koshiba, Tomokazu; Fraaije, Marco W.; Sekiguchi, Hiroshi

    Elucidation of the genetic basis of the control of leaf shape could be of use in the manipulation of crop traits, leading to more stable and increased crop production. To improve our understanding of the process controlling leaf shape, we identified a mutant gene in rice that causes a significant

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

    International Nuclear Information System (INIS)

    Chow, James C L; Grigorov, Grigor N

    2006-01-01

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

  12. Effect of nitrogen supply on leaf growth, leaf nitrogen economy and photosynthetic capacity in potato

    NARCIS (Netherlands)

    Vos, J.; Putten, van der P.E.L.

    1998-01-01

    Literature reports show little effect of nitrogen supply on radiation use efficiency in potato and in other dicotyledonous C3 species. This paper tests the hypothesis that potato reduces leaf size rather than leaf nitrogen concentration and photosynthetic capacity when nitrogen is in short supply.

  13. Prophylactic effect of paw-paw leaf and bitter leaf extracts on the ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-08-18

    Aug 18, 2008 ... (ANOVA) and significant means separated using FLSD = LSD procedure as outlined in Obi (2002). RESULTS AND DISCUSSION. In pre-soaking, paw-paw leaf (PL) extract had no significant effect (P > 0.05) on the disease incidence at. 50% anthesis. Bitter leaf (BL) extract had a high signifi- cant effect (P ...

  14. A Two-Big-Leaf Model for Canopy Temperature, Photosynthesis, and Stomatal Conductance.

    Science.gov (United States)

    Dai, Yongjiu; Dickinson, Robert E.; Wang, Ying-Ping

    2004-06-01

    simulated fluxes by CLM 2L were compared with the observations, and with the results by the CLM with a single big-leaf scheme (CLM 1L) and by the CLM with the assimilation stomatal conductance scheme of NCAR Land Surface Model (LSM). The results showed that CLM 2L was an improvement compared to the CLM 1L and the CLM for the test cases of tropical evergreen broadleaf land cover and coniferous boreal forest.

  15. 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

  16. Identification of Functional Single-Nucleotide Polymorphisms Affecting Leaf Hair Number in Brassica rapa.

    Science.gov (United States)

    Zhang, Wenting; Mirlohi, Shirin; Li, Xiaorong; He, Yuke

    2018-06-01

    Leaf traits affect plant agronomic performance; for example, leaf hair number provides a morphological indicator of drought and insect resistance. Brassica rapa crops have diverse phenotypes, and many B. rapa single-nucleotide polymorphisms (SNPs) have been identified and used as molecular markers for plant breeding. However, which SNPs are functional for leaf hair traits and, therefore, effective for breeding purposes remains unknown. Here, we identify a set of SNPs in the B. rapa ssp. pekinenesis candidate gene BrpHAIRY LEAVES1 ( BrpHL1 ) and a number of SNPs of BrpHL1 in a natural population of 210 B. rapa accessions that have hairy, margin-only hairy, and hairless leaves. BrpHL1 genes and their orthologs and paralogs have many SNPs. By intensive mutagenesis and genetic transformation, we selected the functional SNPs for leaf hairs by the exclusion of nonfunctional SNPs and the orthologous and paralogous genes. The residue tryptophan-92 of BrpHL1a was essential for direct interaction with GLABROUS3 and, thus, necessary for the formation of leaf hairs. The accessions with the functional SNP leading to substitution of the tryptophan-92 residue had hairless leaves. The orthologous BrcHL1b from B. rapa ssp. chinensis regulates hair formation on leaf margins rather than leaf surfaces. The selected SNP for the hairy phenotype could be adopted as a molecular marker for insect resistance in Brassica spp. crops. Moreover, the procedures optimized here can be used to explain the molecular mechanisms of natural variation and to facilitate the molecular breeding of many crops. © 2018 American Society of Plant Biologists. All rights reserved.

  17. 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.

  18. Surviving floods: leaf gas films improve O2 and CO2 exchange, root aeration, and growth of completely submerged rice

    DEFF Research Database (Denmark)

    Pedersen, Ole; Rich, Sarah Meghan; Colmer, Timothy David

    2009-01-01

    When completely submerged, the leaves of some species retain a surface gas film. Leaf gas films on submerged plants have recently been termed 'plant plastrons', analogous with the plastrons of aquatic insects. In aquatic insects, surface gas layers (i.e. plastrons) enlarge the gas–water interface...... or when in light, was improved considerably when leaf gas films were present. Thus, leaf gas films contribute to the submergence tolerance of rice, in addition to those traits already recognized, such as the shoot-elongation response, aerenchyma and metabolic adjustments to O2 deficiency and oxidative...... stress....

  19. Synthesis of monodispersed silver nanoparticles using Hibiscus cannabinus leaf extract and its antimicrobial activity

    Science.gov (United States)

    Bindhu, M. R.; Umadevi, M.

    2013-01-01

    Synthesis of silver nanoparticles using leaf extract of Hibiscus cannabinus has been investigated. The influences of different concentration of H. cannabinus leaf extract, different metal ion concentration and different reaction time on the above cases on the synthesis of nanoparticles were evaluated. The synthesized nanoparticles were characterized using UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). The prepared silver nanoparticles were monodispersed, spherical in shape with the average particle size of 9 nm and shows surface plasmon peak at 446 nm. The study also reveals that the ascorbic acid present in H. cannabinus leaf extract has been used as reducing agent. The prepared silver nanoparticle shows good antimicrobial activity against Escherichia coli, Proteus mirabilis and Shigella flexneri.

  20. Synthesis of monodispersed silver nanoparticles using Hibiscus cannabinus leaf extract and its antimicrobial activity.

    Science.gov (United States)

    Bindhu, M R; Umadevi, M

    2013-01-15

    Synthesis of silver nanoparticles using leaf extract of Hibiscus cannabinus has been investigated. The influences of different concentration of H. cannabinus leaf extract, different metal ion concentration and different reaction time on the above cases on the synthesis of nanoparticles were evaluated. The synthesized nanoparticles were characterized using UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). The prepared silver nanoparticles were monodispersed, spherical in shape with the average particle size of 9 nm and shows surface plasmon peak at 446 nm. The study also reveals that the ascorbic acid present in H. cannabinus leaf extract has been used as reducing agent. The prepared silver nanoparticle shows good antimicrobial activity against Escherichia coli, Proteus mirabilis and Shigella flexneri. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Fatty acid and sterol contents during tulip leaf senescence induced by methyl jasmonate

    Directory of Open Access Journals (Sweden)

    Marian Saniewski

    2013-12-01

    Full Text Available It has been shown previously that methyl jasmonate (JA-Me applied in lanolin paste on the bottom surface of intact tulip leaves causes a rapid and intense its senescence. The aim of this work was to study the effect of JA-Me on free and bound fatty acid and sterol contents during tulip leaf senescence. The main free and bound fatty acids of tulip leaf, in decreasing order of their abundance, were linolenic, linoleic, palmitic, oleic, stearic and myristic acids. Only the content of free linolenic acid decreased after treatment with JA-Me during visible stage of senescence. ß-Sitosterol (highest concentration, campesterol, stigmasterol and cholesterol were identified in tulip leaf. Methyl jasmonate evidently increased the level of ß-sitosterol, campesterol and stigmasterol during induced senescence. It is suggested that the increase in sterol concentrations under the influence of methyl jasmonate induced changes in membrane fluidity and permeability, which may be responsible for senescence.

  2. BOREAS TE-9 NSA Leaf Chlorophyll Density

    Science.gov (United States)

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

    2000-01-01

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

  3. Control of dew and frost formation on leaf by radiative cooling

    International Nuclear Information System (INIS)

    Matsui, T.; Eguchi, H.; Mori, K.

    1981-01-01

    A radiative cooling system was developed to control dew and frost formations and to examine the effect of the radiative cooling on the leaf temperature. The growth chamber was provided with a box which was constructed by using heat insulating materials to minimize the disturbances and to regulate the air current. A cooling coil (cooling surface of 300 cm was equipped at the bottom of the box and manipulated by a refrigerator of 1, 430 kcal hour -1 , and a concave mirror was attached to the ceiling of the box to facilitate the reflection of the radiation from the leaf to the cooling coil. The moisture in air was supplied by flowing the controlled air (0.2 m min -1 ) into the box. The distribution of dew point temperatures was almost uniform horizontally even under vertically slight conversion (downward velocity of 1.3 cm sec -1 ) of the air. The leaf temperature became about 1.0°C lower than the ambient air temperature under the radiative cooling. The dew and the frost were clearly observed on the leaf after the time when the leaf temperature had become lower than the dew point temperature. The dew increased in size in course of time, and the frost varied in shape and in size with the temperatures. Thus, artificial formations of the dew and the frost were made possible by the radiative cooling system developed in this experiment

  4. Study of Tensile Properties and Deflection Temperature of Polypropylene/Subang Pineapple Leaf Fiber Composites

    Science.gov (United States)

    Hafizhah, R.; Juwono, A. L.; Roseno, S.

    2017-05-01

    The development of eco-friendly composites has been increasing in the past four decades because the requirement of eco-friendly materials has been increasing. Indonesia has a lot of natural fiber resources and, pineapple leaf fiber is one of those fibers. This study aimed to determine the influence of weight fraction of pineapple leaf fibers, that were grown at Subang, to the tensile properties and the deflection temperature of polypropylene/Subang pineapple leaf fiber composites. Pineapple leaf fibers were pretreated by alkalization, while polypropylene pellets, as the matrix, were extruded into sheets. Hot press method was used to fabricate the composites. The results of the tensile test and Heat Deflection Temperature (HDT) test showed that the composites that contained of 30 wt.% pineapple leaf fiber was the best composite. The values of tensile strength, modulus of elasticity and deflection temperature were (64.04 ± 3.91) MPa; (3.98 ± 0.55) GPa and (156.05 ± 1.77) °C respectively, in which increased 187.36%, 198.60%, 264.72% respectively from the pristine polypropylene. The results of the observation on the fracture surfaces showed that the failure modes were fiber breakage and matrix failure.

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

    Science.gov (United States)

    Momokawa, Naoko; Kadono, Yasuro; Kudoh, Hiroshi

    2011-11-01

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

  6. Anatomia, ultra-estrutura e secreção do nectário extrafloral de Hibiscus pernambucensis Arruda (Malvaceae)

    OpenAIRE

    Rocha, Joecildo Francisco; Machado, Silvia Rodrigues [UNESP

    2009-01-01

    This paper reports on the extrafloral nectary (EFN) of Hibiscus pernambucensis, a native shrub species occurring in mangrove and restinga along Brazil's coastline. EFNs occur as furrows with a protuberant border on the abaxial surface veins of the leaf blade. Each nectary consists of numerous secretory multicellular trichomes, epidermal cells in palisade-like arrangements and non-vascularized parenchyma tissue. Nectar secretion is prolonged, since secretion starts in very young leaves and rem...

  7. Characterizing the drivers of seedling leaf gas exchange responses to warming and altered precipitation: indirect and direct effects.

    Science.gov (United States)

    Smith, Nicholas G; Pold, Grace; Goranson, Carol; Dukes, Jeffrey S

    2016-01-01

    Anthropogenic forces are projected to lead to warmer temperatures and altered precipitation patterns globally. The impact of these climatic changes on the uptake of carbon by the land surface will, in part, determine the rate and magnitude of these changes. However, there is a great deal of uncertainty in how terrestrial ecosystems will respond to climate in the future. Here, we used a fully factorial warming (four levels) by precipitation (three levels) manipulation experiment in an old-field ecosystem in the northeastern USA to examine the impact of climatic changes on leaf carbon exchange in five species of deciduous tree seedlings. We found that photosynthesis generally increased in response to increasing precipitation and decreased in response to warming. Respiration was less sensitive to the treatments. The net result was greater leaf carbon uptake in wetter and cooler conditions across all species. Structural equation modelling revealed the primary pathway through which climate impacted leaf carbon exchange. Net photosynthesis increased with increasing stomatal conductance and photosynthetic enzyme capacity (V cmax ), and decreased with increasing respiration of leaves. Soil moisture and leaf temperature at the time of measurement most heavily influenced these primary drivers of net photosynthesis. Leaf respiration increased with increasing soil moisture, leaf temperature, and photosynthetic supply of substrates. Counter to the soil moisture response, respiration decreased with increasing precipitation amount, indicating that the response to short- (i.e. soil moisture) versus long-term (i.e. precipitation amount) water stress differed, possibly as a result of changes in the relative amounts of growth and maintenance demand for respiration over time. These data (>500 paired measurements of light and dark leaf gas exchange), now publicly available, detail the pathways by which climate can impact leaf gas exchange and could be useful for testing assumptions in

  8. Induced leaf variations in faba bean

    International Nuclear Information System (INIS)

    Yasin, M.

    1996-01-01

    The frequency and spectrum of M2 chlorophyll and other leaf mutations after gamma ray, ethyl methane sulfonate (EMS) and nitrous oxide (N2O) seed treatment in two varieties of faba bean were studied. In general, cv JV1 was more sensitive and EMS treatment was most effective. The frequency of chlorina-type mutations was higher than that of xantha and chlorotica type chlorophyll mutations. The highest frequency of variations was observed in leaflet texture, followed by arrangement, shape and size in both varieties. The use of these leaf mutations in formulating an ideotype of Vicia faba L. are discussed

  9. Phyllotaxis involves auxin drainage through leaf primordia

    DEFF Research Database (Denmark)

    Deb, Yamini; Marti, Dominik; Frenz, Martin

    2015-01-01

    The spatial arrangement of leaves and flowers around the stem, known as phyllotaxis, is controlled by an auxin-dependent reiterative mechanism that leads to regular spacing of the organs and thereby to remarkably precise phyllotactic patterns. The mechanism is based on the active cellular transport...... of phyllotaxis invoke the accumulation of auxin at leaf initials and removal of auxin through their developing vascular strand, the midvein. We have developed a precise microsurgical tool to ablate the midvein at high spatial and temporal resolution in order to test its function in leaf formation and phyllotaxis...

  10. Leaf density explains variation in leaf mass per area in rice between cultivars and nitrogen treatments.

    Science.gov (United States)

    Xiong, Dongliang; Wang, Dan; Liu, Xi; Peng, Shaobing; Huang, Jianliang; Li, Yong

    2016-05-01

    Leaf mass per area (LMA) is an important leaf trait; however, correlations between LMA and leaf anatomical features and photosynthesis have not been fully investigated, especially in cereal crops. The objectives of this study were (a) to investigate the correlations between LMA and leaf anatomical traits; and (b) to clarify the response of LMA to nitrogen supply and its effect on photosynthetic nitrogen use efficiency (PNUE). In the present study, 11 rice varieties were pot grown under sufficient nitrogen (SN) conditions, and four selected rice cultivars were grown under low nitrogen (LN) conditions. Leaf anatomical traits, gas exchange and leaf N content were measured. There was large variation in LMA across selected rice varieties. Regression analysis showed that the variation in LMA was more closely related to leaf density (LD) than to leaf thickness (LT). LMA was positively related to the percentage of mesophyll tissue area (%mesophyll), negatively related to the percentage of epidermis tissue area (%epidermis) and unrelated to the percentage of vascular tissue area (%vascular). The response of LMA to N supplementation was dependent on the variety and was also mainly determined by the response of LD to N. Compared with SN, photosynthesis was significantly decreased under LN, while PNUE was increased. The increase in PNUE was more critical in rice cultivars with a higher LMA under SN supply. Leaf density is the major cause of the variation in LMA across rice varieties and N treatments, and an increase in LMA under high N conditions would aggravate the decrease in PNUE. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. SU-F-T-350: Continuous Leaf Optimization (CLO) for IMRT Leaf Sequencing

    Energy Technology Data Exchange (ETDEWEB)

    Long, T; Chen, M; Jiang, S; Lu, W [UT Southwestern Medical Center, Dallas, TX (United States)

    2016-06-15

    Purpose: To study a new step-and-shoot IMRT leaf sequencing model that avoids the two main pitfalls of conventional leaf sequencing: (1) target fluence being stratified into a fixed number of discrete levels and/or (2) aperture leaf positions being restricted to a discrete set of locations. These assumptions induce error into the sequence or reduce the feasible region of potential plans, respectively. Methods: We develop a one-dimensional (single leaf pair) methodology that does not make assumptions (1) or (2) that can be easily extended to a multi-row model. The proposed continuous leaf optimization (CLO) methodology takes in an existing set of apertures and associated intensities, or solution “seed,” and improves the plan without the restrictiveness of 1or (2). It then uses a first-order descent algorithm to converge onto a locally optimal solution. A seed solution can come from models that assume (1) and (2), thus allowing the CLO model to improve upon existing leaf sequencing methodologies. Results: The CLO model was applied to 208 generated target fluence maps in one dimension. In all cases for all tested sequencing strategies, the CLO model made improvements on the starting seed objective function. The CLO model also was able to keep MUs low. Conclusion: The CLO model can improve upon existing leaf sequencing methods by avoiding the restrictions of (1) and (2). By allowing for more flexible leaf positioning, error can be reduced when matching some target fluence. This study lays the foundation for future models and solution methodologies that can incorporate continuous leaf positions explicitly into the IMRT treatment planning model. Supported by Cancer Prevention & Research Institute of Texas (CPRIT) - ID RP150485.

  12. Simulated Acid Rain-induced Alterations in Flowering, Leaf ...

    African Journals Online (AJOL)

    Evaluation of SAR effects on budding, flowering, leaf abscission and pollen development revealed that ... Keywords: Simulated acid rain, Helianthus annuus, flowering, leaf abscission, pollen germination, sunflower. ... HOW TO USE AJOL.

  13. Primate numts and reticulate evolution of capped and golden leaf ...

    Indian Academy of Sciences (India)

    PRAKASH KUMAR

    A recent phylogenetic study of langurs and leaf monkeys of South Asia suggested a reticulate evolution of capped and golden leaf ..... Accordingly, transversions were weighted .... lineages. Most taxonomic schemes published till date place.

  14. Performance of broiler chickens fed on Moringa oleifera leaf meal ...

    African Journals Online (AJOL)

    Performance of broiler chickens fed on Moringa oleifera leaf meal ... This exploratory study was conducted to investigate the effect of Moringa oleifera leaf meal ... ratio were evaluated for the individual replicate of each dietary treatment.

  15. Antibacterial Activity of Vernonia amygdalina Leaf Extracts against ...

    African Journals Online (AJOL)

    ADOWIE PERE

    (Bitter leaf), Allium sativum (Garlic), O. gratissimum. (Scent leaf) ... complex active components that are useful ... hydroxide was added. .... KEY: CPX-Ciprofloxacin, Ro-Rocephin, St-Streptomycin, AU-Augmentin, SXT-Septrin, SP- Sparfloxacin, ...

  16. 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.

  17. 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

  18. Sound Absorption and Friction Properties of Nano-Lotus Leaf Coated Concrete for Rigid Pavement

    Directory of Open Access Journals (Sweden)

    Marcelo GONZALEZ

    2016-09-01

    Full Text Available This paper presents the feasibility of superhydrophobic films to create the nano-lotus leaf effect on concrete surface and their influence on sound absorption and friction properties of concrete for application in rigid pavements. The study involved an evaluation of nanomaterials at the laboratory scale to analyze the effects of microtexture modification on the friction and sound absorption of concrete pavement. A number of laboratory specimens were produced by applying different amounts of nano-lotus leaf coating on the top of the textured concrete surface. The British pendulum test was used to measure the friction number, and an impedance tube was used to determine the sound absorption coefficient. Laboratory results indicate that nano-lotus leaf coated concrete can maintain the required friction property for rigid pavement, but may not increase the noise absorption. Further research must be carried out to determine possible benefit of the lotus leaf effect for reducing hydroplaning, particularly during heavy rainfall.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.7638

  19. Characterization of leaf waste based biochar for cost effective hydrogen sulphide removal from biogas.

    Science.gov (United States)

    Sahota, Shivali; Vijay, Virendra Kumar; Subbarao, P M V; Chandra, Ram; Ghosh, Pooja; Shah, Goldy; Kapoor, Rimika; Vijay, Vandit; Koutu, Vaibhav; Thakur, Indu Shekhar

    2018-02-01

    Installation of decentralized units for biogas production along with indigenous upgradation systems can be an effective approach to meet growing energy demands of the rural population. Therefore, readily available leaf waste was used to prepare biochar at different temperatures and employed for H 2 S removal from biogas produced via anaerobic digestion plant. It is found that biochar prepared via carbonization of leaf waste at 400 °C effectively removes 84.2% H 2 S (from 1254 ppm to 201 ppm) from raw biogas for 25 min in a continuous adsorption tower. Subsequently, leaf waste biochar compositional, textural and morphological properties before and after H 2 S adsorption have been analyzed using proximate analysis, CHNS, BET surface area, FTIR, XRD, and SEM-EDX. It is found that BET surface area, pore size, and textural properties of leaf waste biochar plays a crucial role in H 2 S removal from the biogas. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2012-06-21

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

  1. Leaf cuticle variations in amaranthus spinousus as indicators of environmental pollution

    International Nuclear Information System (INIS)

    Otoide, J.E.; Kayode, J.

    2007-01-01

    Investigation of the leaf epidermal characteristics of Amaranthus spinosus from polluted and non-polluted populations revealed that the stomatal pores of the leaves of the plants of the polluted areas were closed whereas those of the non-polluted areas were open. Mean length x mean width of stomatal pores on the upper leaf surface were 0.86 micro x 0.43 micro and 1.23 micro x 0.45 micro on the lower leaf surface of the non polluted microhabitats. Also, the leaves of the polluted population were smaller than those of the non-polluted population. The average leaf area of the plants of the Polluted population was 7.64 cm/sub -2/ against 12.13 cm/sub 2/ of the plants of the non-polluted areas. The results were attributed to the combined effects of air pollutant that predominated roadsides from where the samples were taken. Thus it is inferred that this plant could serve as bio-indicator of air pollution. (author)

  2. Variable depth recursion algorithm for leaf sequencing

    International Nuclear Information System (INIS)

    Siochi, R. Alfredo C.

    2007-01-01

    The processes of extraction and sweep are basic segmentation steps that are used in leaf sequencing algorithms. A modified version of a commercial leaf sequencer changed the way that the extracts are selected and expanded the search space, but the modification maintained the basic search paradigm of evaluating multiple solutions, each one consisting of up to 12 extracts and a sweep sequence. While it generated the best solutions compared to other published algorithms, it used more computation time. A new, faster algorithm selects one extract at a time but calls itself as an evaluation function a user-specified number of times, after which it uses the bidirectional sweeping window algorithm as the final evaluation function. To achieve a performance comparable to that of the modified commercial leaf sequencer, 2-3 calls were needed, and in all test cases, there were only slight improvements beyond two calls. For the 13 clinical test maps, computation speeds improved by a factor between 12 and 43, depending on the constraints, namely the ability to interdigitate and the avoidance of the tongue-and-groove under dose. The new algorithm was compared to the original and modified versions of the commercial leaf sequencer. It was also compared to other published algorithms for 1400, random, 15x15, test maps with 3-16 intensity levels. In every single case the new algorithm provided the best solution

  3. ANTIFUNGAL ACTIVITY OF ETHANOLIC LEAF EXTRACT OF ...

    African Journals Online (AJOL)

    Ethanolic leaf extract of Eucalyptus camaldulensis, dispersed in a concentrated sugar solution had marked fungicidal effect against clinical dermatophytic fungal isolates; Microsporium gypseum and Trichophyton mentagrophytes. Microsporium gypseum at an inoculum level of 4.8 x 103 cfu/ml and T. mentagrophytes at ...

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

    Directory of Open Access Journals (Sweden)

    George D. Nanos

    2013-12-01

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

  5. Short Communication: The developmentt of a leaf tensilmeter for in ...

    African Journals Online (AJOL)

    The development of a portable leaf tensilmeter for the in situ measurement of leaf tensile strength is described. Tensile strength is determined by the distortion of strain gauges on modified stripping pliers which are used to break leaf blades. The output is displayed via an analogue chip through a liquid crystal display.

  6. Leaf area prediction models for Tsuga canadensis in Maine

    Science.gov (United States)

    Laura S. Kenefic; R.S. Seymour

    1999-01-01

    Tsuga canadensis (L.) Carr. (eastern hemlock) is a common species throughout the Acadian forest. Studies of leaf area and growth efficiency in this forest type have been limited by the lack of equations to predict leaf area of this species. We found that sapwood area was an effective leaf area surrogate in T. canadensis, though...

  7. Study on creation of an indocalamus leaf flavor

    Directory of Open Access Journals (Sweden)

    Guangyong ZHU

    2015-01-01

    Full Text Available AbstractFlavors represent a small but significant segment of food industry. Sensory characteristics play an important role in the process of consumer acceptance and preference. Indocalamus leaf takes on a pleasant odor and indocalamus leaf flavor can be used in many products. However, indocalamus leaf flavor formula has not been reported. Therefore, developing an indocalamus leaf flavor is of significant interests. Note is a distinct flavor or odor characteristic. This paper concentrates on preparation and creation of indocalamus leaf flavor according to the notes of indocalamus leaf. The notes were obtained by smelling indocalamus leaf, and the results showed that the notes of indocalamus leaf flavor can be classified as: green-leafy note, sweet note, beany note, aldehydic note, waxy note, woody note, roast note, creamy note, and nutty note. According to the notes of indocalamus leaf odor, a typical indocalamus leaf flavor formula was obtained. The indocalamus leaf flavor blended is pleasant, harmonious, and has characteristics of indocalamus leaf odor.

  8. Does leaf chemistry differentially affect breakdown in tropical versus temperate streams? Importance of standardized analytical techniques to measure leaf chemistry

    Science.gov (United States)

    Marcelo Ardon; Catherine M. Pringle; Susan L. Eggert

    2009-01-01

    Comparisons of the effects of leaf litter chemistry on leaf breakdown rates in tropical vs temperate streams are hindered by incompatibility among studies and across sites of analytical methods used to...

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

    Science.gov (United States)

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

    2017-04-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    International Nuclear Information System (INIS)

    Rosa, L.M.G.

    1993-01-01

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

  12. Green light drives leaf photosynthesis more efficiently than red light in strong white light: revisiting the enigmatic question of why leaves are green.

    Science.gov (United States)

    Terashima, Ichiro; Fujita, Takashi; Inoue, Takeshi; Chow, Wah Soon; Oguchi, Riichi

    2009-04-01

    The literature and our present examinations indicate that the intra-leaf light absorption profile is in most cases steeper than the photosynthetic capacity profile. In strong white light, therefore, the quantum yield of photosynthesis would be lower in the upper chloroplasts, located near the illuminated surface, than that in the lower chloroplasts. Because green light can penetrate further into the leaf than red or blue light, in strong white light, any additional green light absorbed by the lower chloroplasts would increase leaf photosynthesis to a greater extent than would additional red or blue light. Based on the assessment of effects of the additional monochromatic light on leaf photosynthesis, we developed the differential quantum yield method that quantifies efficiency of any monochromatic light in white light. Application of this method to sunflower leaves clearly showed that, in moderate to strong white light, green light drove photosynthesis more effectively than red light. The green leaf should have a considerable volume of chloroplasts to accommodate the inefficient carboxylation enzyme, Rubisco, and deliver appropriate light to all the chloroplasts. By using chlorophylls that absorb green light weakly, modifying mesophyll structure and adjusting the Rubisco/chlorophyll ratio, the leaf appears to satisfy two somewhat conflicting requirements: to increase the absorptance of photosynthetically active radiation, and to drive photosynthesis efficiently in all the chloroplasts. We also discuss some serious problems that are caused by neglecting these intra-leaf profiles when estimating whole leaf electron transport rates and assessing photoinhibition by fluorescence techniques.

  13. Tunable hydrodynamic characteristics in microchannels with biomimetic superhydrophobic (lotus leaf replica) walls.

    Science.gov (United States)

    Dey, Ranabir; Raj M, Kiran; Bhandaru, Nandini; Mukherjee, Rabibrata; Chakraborty, Suman

    2014-05-21

    The present work comprehensively addresses the hydrodynamic characteristics through microchannels with lotus leaf replica (exhibiting low adhesion and superhydrophobic properties) walls. The lotus leaf replica is fabricated following an efficient, two-step, soft-molding process and is then integrated with rectangular microchannels. The inherent biomimetic, superhydrophobic surface-liquid interfacial hydrodynamics, and the consequential bulk flow characteristics, are critically analyzed by the micro-particle image velocimetry technique. It is observed that the lotus leaf replica mediated microscale hydrodynamics comprise of two distinct flow regimes even within the low Reynolds number paradigm, unlike the commonly perceived solely apparent slip-stick dominated flows over superhydrophobic surfaces. While the first flow regime is characterized by an apparent slip-stick flow culminating in an enhanced bulk throughput rate, the second flow regime exhibits a complete breakdown of the aforementioned laminar and uni-axial flow model, leading to a predominantly no-slip flow. Interestingly, the critical flow condition dictating the transition between the two hydrodynamic regimes is intrinsically dependent on the micro-confinement effect. In this regard, an energetically consistent theoretical model is also proposed to predict the alterations in the critical flow condition with varying microchannel configurations, by addressing the underlying biomimetic surface-liquid interfacial conditions. Hence, the present research endeavour provides a new design-guiding paradigm for developing multi-functional microfluidic devices involving biomimetic, superhydrophobic surfaces, by judicious exploitation of the tunable hydrodynamic characteristics in the two regimes.

  14. Baby leaf lettuce germplasm enhancement: developing diverse populations with resistance to bacterial leaf spot caused by Xanthomonas campestris pv. vitians

    Science.gov (United States)

    Baby leaf lettuce cultivars with resistance to bacterial leaf spot (BLS) caused by Xanthomonas campestris pv. vitians (Xcv) are needed to reduce crop losses. The objectives of this research were to assess the genetic diversity for BLS resistance in baby leaf lettuce cultivars and to select early gen...

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

    Science.gov (United States)

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

  16. Does leaf chemistry differentially affect breakdown in tropical vs temperate streams? Importance of standardized analytical techniques to measure leaf chemistry

    Science.gov (United States)

    Marcelo Ard& #243; n; Catherine M. Pringle; Susan L. Eggert

    2009-01-01

    Comparisons of the effects of leaf litter chemistry on leaf breakdown rates in tropical vs temperate streams are hindered by incompatibility among studies and across sites of analytical methods used to measure leaf chemistry. We used standardized analytical techniques to measure chemistry and breakdown rate of leaves from common riparian tree species at 2 sites, 1...

  17. Seasonal variations of leaf and canopy properties tracked by ground-based NDVI imagery in a temperate forest.

    Science.gov (United States)

    Yang, Hualei; Yang, Xi; Heskel, Mary; Sun, Shucun; Tang, Jianwu

    2017-04-28

    Changes in plant phenology affect the carbon flux of terrestrial forest ecosystems due to the link between the growing season length and vegetation productivity. Digital camera imagery, which can be acquired frequently, has been used to monitor seasonal and annual changes in forest canopy phenology and track critical phenological events. However, quantitative assessment of the structural and biochemical controls of the phenological patterns in camera images has rarely been done. In this study, we used an NDVI (Normalized Difference Vegetation Index) camera to monitor daily variations of vegetation reflectance at visible and near-infrared (NIR) bands with high spatial and temporal resolutions, and found that the infrared camera based NDVI (camera-NDVI) agreed well with the leaf expansion process that was measured by independent manual observations at Harvard Forest, Massachusetts, USA. We also measured the seasonality of canopy structural (leaf area index, LAI) and biochemical properties (leaf chlorophyll and nitrogen content). We found significant linear relationships between camera-NDVI and leaf chlorophyll concentration, and between camera-NDVI and leaf nitrogen content, though weaker relationships between camera-NDVI and LAI. Therefore, we recommend ground-based camera-NDVI as a powerful tool for long-term, near surface observations to monitor canopy development and to estimate leaf chlorophyll, nitrogen status, and LAI.

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

    Science.gov (United States)

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

    2014-01-01

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

  19. Impact of collimator leaf width on stereotactic radiosurgery and 3D conformal radiotherapy treatment plans

    International Nuclear Information System (INIS)

    Kubo, H. Dale; Wilder, Richard B.; Pappas, Conrad T.E.

    1999-01-01

    Purpose: The authors undertook a study to analyze the impact of collimator leaf width on stereotactic radiosurgery and 3D conformal radiotherapy treatment plans. Methods and Materials: Twelve cases involving primary brain tumors, metastases, or arteriovenous malformations that had been planned with BrainLAB's conventional circular collimator-based radiosurgery system were re-planned using a β-version of BrainLAB's treatment planning software that is compatible with MRC Systems' and BrainLAB's micro-multileaf collimators. These collimators have a minimum leaf width of 1.7 mm and 3.0 mm, respectively, at isocenter. The clinical target volumes ranged from 2.7-26.1 cc and the number of static fields ranged from 3-5. In addition, for 4 prostate cancer cases, 2 separate clinical target volumes were planned using MRC Systems' and BrainLAB's micro-multileaf collimators and Varian's multileaf collimator: the smaller clinical target volume consisted of the prostate gland and the larger clinical target volume consisted of the prostate and seminal vesicles. For the prostate cancer cases, treatment plans were generated using either 6 or 7 static fields. A 'PITV ratio', which the Radiation Therapy Oncology Group defines as the volume encompassed by the prescription isodose surface divided by the clinical target volume, was used as a measure of the quality of treatment plans (a PITV ratio of 1.0-2.0 is desirable). Bladder and rectal volumes encompassed by the prescription isodose surface, isodose distributions and dose volume histograms were also analyzed for the prostate cancer patients. Results: In 75% of the cases treated with radiosurgery, a PITV ratio between 1.0-2.0 could be achieved using a micro-multileaf collimator with a leaf width of 1.7-3.0 mm at isocenter and 3-5 static fields. When the clinical target volume consisted of the prostate gland, the micro-multileaf collimator with a minimum leaf width of 3.0 mm allowed one to decrease the median volume of bladder and

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

    Energy Technology Data Exchange (ETDEWEB)

    Bouriaud, O. [Inst. National de la Recherche Agronomique, Centre de Recherches Forestieres de Nancy, Champenoux (France); Soudani, K. [Univ. Paris-Sud XI, Dept. d' Ecophysiologie Vegetale, Lab. Ecologie Systematique et Evolution, Orsay Cedex (France); Breda, N. [Inst. National de la Recherche Agronomique, Centre de Recherches Forestieres de Nancy, Champenoux (France)

    2003-06-01

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

  1. 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

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

    International Nuclear Information System (INIS)

    Isoda, A.; Wang, P.

    2001-01-01

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

  3. Use of NAP gene to manipulate leaf senescence in plants

    Science.gov (United States)

    Gan, Susheng; Guo, Yongfeng

    2013-04-16

    The present invention discloses transgenic plants having an altered level of NAP protein compared to that of a non-transgenic plant, where the transgenic plants display an altered leaf senescence phenotype relative to a non-transgenic plant, as well as mutant plants comprising an inactivated NAP gene, where mutant plants display a delayed leaf senescence phenotype compared to that of a non-mutant plant. The present invention also discloses methods for delaying leaf senescence in a plant, as well as methods of making a mutant plant having a decreased level of NAP protein compared to that of a non-mutant plant, where the mutant plant displays a delayed leaf senescence phenotype relative to a non-mutant plant. Methods for causing precocious leaf senescence or promoting leaf senescence in a plant are also disclosed. Also disclosed are methods of identifying a candidate plant suitable for breeding that displays a delayed leaf senescence and/or enhanced yield phenotype.

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

    Science.gov (United States)

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

    2015-12-01

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

  5. Constructing seasonal LAI trajectory by data-model fusion for global evergreen needle-leaf forests

    Science.gov (United States)

    Wang, R.; Chen, J.; Mo, G.

    2010-12-01

    For decades, advancements in optical remote sensors made it possible to produce maps of a biophysical parameter--the Leaf Area Index (LAI), which is critically necessary in regional and global modeling of exchanges of carbon, water, energy and other substances, across large areas in a fast way. Quite a few global LAI products have been generated since 2000, e.g. GLOBCARBON (Deng et al., 2006), MODIS Collection 5 (Shabanov et al., 2007), CYCLOPES (Baret et al., 2007), etc. Albeit these progresses, the basic physics behind the technology restrains it from accurate estimation of LAI in winter, especially for northern high-latitude evergreen needle-leaf forests. Underestimation of winter LAI in these regions has been reported in literature (Yang et al., 2000; Cohen et al., 2003; Tian et al., 2004; Weiss et al., 2007; Pisek et al., 2007), and the distortion is usually attributed to the variations of canopy reflectance caused by understory change (Weiss et al., 2007) as well as by the presence of ice and snow on leaves and ground (Cohen, 2003; Tian et al., 2004). Seasonal changes in leaf pigments can also be another reason for low LAI retrieved in winter. Low conifer LAI values in winter retrieved from remote sensing make them unusable for surface energy budget calculations. To avoid these drawbacks of remote sensing approaches, we attempt to reconstruct the seasonal LAI trajectory through model-data fusion. A 1-degree LAI map of global evergreen needle-leaf forests at 10-day interval is produced based on the carbon allocation principle in trees. With net primary productivity (NPP) calculated by the Boreal Ecosystems Productivity Simulator (BEPS) (Chen et al., 1999), carbon allocated to needles is quantitatively evaluated and then can be further transformed into LAI using the specific leaf area (SLA). A leaf-fall scheme is developed to mimic the carbon loss caused by falling needles throughout the year. The seasonally maximum LAI from remote sensing data for each pixel

  6. Leaf anatomical changes in Populus trichocarpa, Quercus rubra, Pseudotsuga menziesii and Pinus ponderosa exposed to enhanced ultraviolet-B radiation

    International Nuclear Information System (INIS)

    Nagel, L.M.; Bassman, J.H.; Edwards, G.E.; Robberecht, R.; Franceshi, V.R.

    1998-01-01

    Leaf anatomical characteristics are important in determining the degree of injury sustained when plants are exposed to natural and enhanced levels of ultraviolet-B (UV-B) radiation (280–320 nm). The degree to which leaf anatomy can adapt to the increasing levels of UV-B radiation reaching the earth's surface is poorly understood in most tree species. We examined four tree species, representing a wide range of leaf anatomical characteristics, to determine responses of leaf area, specific leaf weight, and leaf tissue parameters after exposure to ambient and enhanced levels of UV-B radiation. Seedlings were grown in a greenhouse with photosynthetically active radiation of 39 mol m −2 day −1 and under one of three daily irradiances of biologically effective UV-B radiation (UV-BBE) supplied for 10 h per day: (1) approximate ambient level received at Pullman, Washington on June 21 (1 x ); two times ambient (2 x ), or three times ambient (3 x ). We hypothesized the response of each species to UV-B radiation would be related to inherent anatomical differences. We found that the conifers responded anatomically to nearly an equal degree as the broad-leaved trees, but that different tissues were involved. Populus trichocarpa, an indeterminate broadleaf species, showed significantly thicker palisade parenchyma in recently mature leaves at the 3 x level and in older leaves under the 2 x level. In addition, individual leaf area was generally greater with increased UV-B irradiance. Quercus rubra, a semi-determinate broadleaf species, exhibited significantly thicker palisade parenchyma at the 2 x and 3 x levels as compared to controls. Psuedotsuga menziesii, an evergreen coniferous species with bifacially flattened needles, and Pinus ponderosa, an evergreen coniferous species with a complete hypodermis, showed no significant change in leaf area or specific leaf weight under enhanced UV-B radiation. Epidermal thickness was unchanged in P. menziesii. However, P. ponderosa

  7. Leaf endophyte load influences fungal garden development in leaf-cutting ants

    Directory of Open Access Journals (Sweden)

    Van Bael Sunshine A

    2012-11-01

    Full Text Available Abstract Background Previous work has shown that leaf-cutting ants prefer to cut leaf material with relatively low fungal endophyte content. This preference suggests that fungal endophytes exact a cost on the ants or on the development of their colonies. We hypothesized that endophytes may play a role in their host plants’ defense against leaf-cutting ants. To measure the long-term cost to the ant colony of fungal endophytes in their forage material, we conducted a 20-week laboratory experiment to measure fungal garden development for colonies that foraged on leaves with low or high endophyte content. Results Colony mass and the fungal garden dry mass did not differ significantly between the low and high endophyte feeding treatments. There was, however, a marginally significant trend toward greater mass of fungal garden per ant worker in the low relative to the high endophyte treatment. This trend was driven by differences in the fungal garden mass per worker from the earliest samples, when leaf-cutting ants had been foraging on low or high endophyte leaf material for only 2 weeks. At two weeks of foraging, the mean fungal garden mass per worker was 77% greater for colonies foraging on leaves with low relative to high endophyte loads. Conclusions Our data suggest that the cost of endophyte presence in ant forage material may be greatest to fungal colony development in its earliest stages, when there are few workers available to forage and to clean leaf material. This coincides with a period of high mortality for incipient colonies in the field. We discuss how the endophyte-leaf-cutter ant interaction may parallel constitutive defenses in plants, whereby endophytes reduce the rate of colony development when its risk of mortality is greatest.

  8. Growth of the C4 dicot Flaveria bidentis: photosynthetic acclimation to low light through shifts in leaf anatomy and biochemistry.

    Science.gov (United States)

    Pengelly, Jasper J L; Sirault, Xavier R R; Tazoe, Youshi; Evans, John R; Furbank, Robert T; von Caemmerer, Susanne

    2010-09-01

    In C(4) plants, acclimation to growth at low irradiance by means of anatomical and biochemical changes to leaf tissue is considered to be limited by the need for a close interaction and coordination between bundle sheath and mesophyll cells. Here differences in relative growth rate (RGR), gas exchange, carbon isotope discrimination, photosynthetic enzyme activity, and leaf anatomy in the C(4) dicot Flaveria bidentis grown at a low (LI; 150 micromol quanta m(2) s(-1)) and medium (MI; 500 micromol quanta m(2) s(-1)) irradiance and with a 12 h photoperiod over 36 d were examined. RGRs measured using a 3D non-destructive imaging technique were consistently higher in MI plants. Rates of CO(2) assimilation per leaf area measured at 1500 micromol quanta m(2) s(-1) were higher for MI than LI plants but did not differ on a mass basis. LI plants had lower Rubisco and phosphoenolpyruvate carboxylase activities and chlorophyll content on a leaf area basis. Bundle sheath leakiness of CO(2) (phi) calculated from real-time carbon isotope discrimination was similar for MI and LI plants at high irradiance. phi increased at lower irradiances, but more so in MI plants, reflecting acclimation to low growth irradiance. Leaf thickness and vein density were greater in MI plants, and mesophyll surface area exposed to intercellular airspace (S(m)) and bundle sheath surface area per unit leaf area (S(b)) measured from leaf cross-sections were also both significantly greater in MI compared with LI leaves. Both mesophyll and bundle sheath conductance to CO(2) diffusion were greater in MI compared with LI plants. Despite being a C(4) species, F. bidentis is very plastic with respect to growth irradiance.

  9. Transcriptional analyses of natural leaf senescence in maize.

    Directory of Open Access Journals (Sweden)

    Wei Yang Zhang

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

  10. Locomotion and attachment of leaf beetle larvae Gastrophysa viridula (Coleoptera, Chrysomelidae)

    OpenAIRE

    Zurek, Daniel B.; Gorb, Stanislav N.; Voigt, Dagmar

    2015-01-01

    While adult green dock leaf beetles Gastrophysa viridula use tarsal adhesive setae to attach to and walk on smooth vertical surfaces and ceilings, larvae apply different devices for similar purposes: pretarsal adhesive pads on thoracic legs and a retractable pygopod at the 10th abdominal segment. Both are soft smooth structures and capable of wet adhesion. We studied attachment ability of different larval instars, considering the relationship between body weight and real contact area between ...

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

    Science.gov (United States)

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

    2011-12-01

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

  12. A model-based approach to preplanting risk assessment for gray leaf spot of maize.

    Science.gov (United States)

    Paul, P A; Munkvold, G P

    2004-12-01

    ABSTRACT Risk assessment models for gray leaf spot of maize, caused by Cercospora zeae-maydis, were developed using preplanting site and maize genotype data as predictors. Disease severity at the dough/dent plant growth stage was categorized into classes and used as the response variable. Logistic regression and classification and regression tree (CART) modeling approaches were used to predict severity classes as a function of planting date (PD), amount of maize soil surface residue (SR), cropping sequence, genotype maturity and gray leaf spot resistance (GLSR) ratings, and longitude (LON). Models were development using 332 cases collected between 1998 and 2001. Thirty cases collected in 2002 were used to validate the models. Preplanting data showed a strong relationship with late-season gray leaf spot severity classes. The most important predictors were SR, PD, GLSR, and LON. Logistic regression models correctly classified 60 to 70% of the validation cases, whereas the CART models correctly classified 57 to 77% of these cases. Cases misclassified by the CART models were mostly due to overestimation, whereas the logistic regression models tended to misclassify cases by underestimation. Both the CART and logistic regression models have potential as management decision-making tools. Early quantitative assessment of gray leaf spot risk would allow for more sound management decisions being made when warranted.

  13. High Diversity Revealed in Leaf-Associated Protists (Rhizaria: Cercozoa) of Brassicaceae.

    Science.gov (United States)

    Ploch, Sebastian; Rose, Laura E; Bass, David; Bonkowski, Michael

    2016-09-01

    The largest biological surface on earth is formed by plant leaves. These leaf surfaces are colonized by a specialized suite of leaf-inhabiting microorganisms, recently termed "phyllosphere microbiome". Microbial prey, however, attract microbial predators. Protists in particular have been shown to structure bacterial communities on plant surfaces, but virtually nothing is known about the community composition of protists on leaves. Using newly designed specific primers targeting the 18S rDNA gene of Cercozoa, we investigated the species richness of this common protist group on leaves of four Brassicaceae species from two different locations in a cloning-based approach. The generated sequences revealed a broad diversity of leaf-associated Cercozoa, mostly bacterial feeders, but also including known plant pathogens and a taxon of potential endophytes that were recently described as algal predators in freshwater systems. This initial study shows that protists must be regarded as an integral part of the microbial diversity in the phyllosphere of plants. © 2016 The Authors. The Journal of Eukaryotic Microbiology published by Wiley Periodicals, Inc. on behalf of International Society of Protistologists.

  14. [Latitude variation mechanism of leaf traits of Metasequoia glyptostroboides in eastern coastal China].

    Science.gov (United States)

    Guo, Wei Hong; Wang, Hua; Yu, Mu Kui; Wu, Tong Gui; Han, You Zhi

    2017-03-18

    We analyzed the rules of Metasequoia glyptostroboides along with latitude, including leaf length, leaf width, leaf perimeter, leaf area, ratio of leaf length to width, specific leaf area (SLA), and leaf dry mass based on eight stands growing at different latitudes in the coastal area of eastern China, as well as their relationships with climatic and soil factors. The results showed that the leaf length, leaf width and leaf perimeter increased with increasing latitude, while the leaf area and SLA firstly increased and then decreased. The mean annual temperature and annual precipitation were the major environmental factors affecting the leaf traits along latitude gradient. With the increase of soil N content, the SLA decreased firstly and then increased, while the leaf mass decreased significantly. With the increase of soil P content, the SLA increased, and the leaf mass decreased significantly.

  15. Early detection of injuries in leaves of Clusia hilariana Schltdl. (Clusiaceae caused by particulate deposition of iron

    Directory of Open Access Journals (Sweden)

    Diego Ismael Rocha

    2014-06-01

    Full Text Available This study aims to evaluate the prognostic value of microscopic parameters of asymptomatic leaves of Clusia hilariana Schltdl. subjected to particulate deposition of iron (2.14 mg cm-2 day-1 for 45 consecutive days. Samples of young and expanded leaves without symptoms were collected and subjected to light and scanning electron microscopy techniques. The height of the epidermal cells on both surfaces of the leaf and the thickness of the hypodermis, the chlorophyll parenchyma, and the leaf blade were measured. Micromorphological injury occurred in the abaxial surface of young leaves and on both surfaces of expanded leaves. Erosion of the epicuticular wax and cuticle rupture were frequent on the adaxial surface, while on the abaxial surface of both leaves there was a loss of sinuosity on the anticlinal wall of the epidermal cells, stomatal deformity and obstruction. Micromorphometric alterations were seen in all leaf tissues except in the height of epidermic cells, probably due to the thick cuticle and prominent cuticular flanges. The highest difference in thickness of the leaf blade was seen in young leaves of plants subjected to SPMFe, indicating greater sensibility to particulate iron in comparison to the expanded leaves. The micromorphological and micromorphometric alterations in the leaf blade of Clusia hilariana Schltdl. showed the prognostic potential of these tools on the evaluation of impacts caused by the deposition of particulate matter, especially in the 'Restinga' natural vegetation, where the exposure is increasing due to the presence of iron ore industry in their surroundings.

  16. Using Leaf Samples to Establish a Library of Tropical Leaf Fingerprints

    Science.gov (United States)

    Ngo, P.; Nguyen, R.; Anderson, C.; Weiss, P.

    2010-12-01

    Variation in leaf chemistry is directly expressed in spectroscopic patterns of tropical canopies. The goal of the Spectranomics project is to explore this variation in the hopes of developing a method to measure tropical forest diversity remotely from airborne or space-bound spectroscopy in the future. We analyzed tomato leaves for various chemical compositions to better understand the Spectranomics approach to quantifying chemical data of tropical species. We also compared our data to standard data in each analysis. Our results allow us to give the tomato leaves a chemical signature in which we are able to use to compare to other leaf samples. Using this process, we are able to create a library of leaf signatures and document the variety of tree species in tropical forests around the world.

  17. The hepatotoxicity of Ageratum conyzoides leaf in experimental rats

    Directory of Open Access Journals (Sweden)

    Yulvian Sani

    1998-03-01

    Full Text Available Five extracts were obtained from Ageratum conyzoides leaf extracted in methanol-water (4 :1. They were neutral extract (in ethyl acetate, moderately polar extract (in chloroform; basic extract (in chloroform-methanol, polar extract (in methanol, and filtrate. Three extracts were tested biologically and the moderately polar extract was found to be most toxic for female Wistar rats . While the toxicity of neutral extract was mild and other extracts were non-toxic. Therefore, the moderately polar extract was investigated for the hepatoxicity effects in the present study. Intragastric dosing of this extract in rats has caused mortality with clinical signs of weakness, low activity and death. Pathological examination showed mottling on the capsular surface of liver. Microscopically showed anisokaryosis, megalocytosis, bile duct cells proliferation and necrosis . Multiple dosing of this extract may lead to liver and lung injury showing anisokaryosis, megalocytosis, bile duct cells proliferation, centrolobular necrosis, vacuolisation, mitotic figures and mononuclear cells infiltration in the liver and epithelialisation of alveolar walls, thickening of alveolar walls and oedema in the lungs. Liver regeneration occurred 7 days after the last dosing showing mitotic figures and return to the normal structure of liver. The average body weight gain reduced during the first 3 weeks of intoxication from 127.6 g. on predosing to 120,4 g. on week-3 followed by an increased on body weight until the last experiment to 130.8 g. when dosing of extract was terminated . There was an increased of alanine amino transferase ( ALAT during the first 2 days after dosing from 14.6 IU/1 to 23 .0 IU/1 and reduced at the following days to 7.5 IU/1 at day-5 after dosing . Dosing with retrorsin has caused an increased in ALAT consistently during the first 5 days to 8.7 IU/1 . The activity of aspartate amino transferase (ASAT reduced during the first 3 days after dosing with the

  18. Role of residual stresses induced by double peening on fatigue durability of automotive leaf springs

    International Nuclear Information System (INIS)

    Scuracchio, Bruno Geoffroy; Batista de Lima, Nelson; Schön, Cláudio Geraldo

    2013-01-01

    Highlights: ► Proper choice of peening media is needed for higher fatigue strength in leaf springs. ► Optimum double-peening condition for leaf springs: 0.8 mm shot, followed by 0.3 mm. ► Fatigue life correlates with residual stress levels at the surface (up to 0.02 mm). ► Residual stress profile below 0.02 mm has no measurable effect over fatigue life. ► Failure of the investigated parts is nucleation-controlled. - Abstract: Improvement of fatigue life in parts subjected to cyclic stresses by application of mechanical surface treatment processes is already well known, both in the industry and in the academy. Dealing with automotive springs, the shot peening process becomes an essential step in manufacturing. In the case of leaf springs, however, a systematic investigation of the effect of shot peening on fatigue life is still required. The aim of the present work is to improve the knowledge on the role of shot peening in manufacturing leaf springs for vehicles, through the analysis of residual stresses by X-ray diffraction and fatigue tests on a series of samples that were subject to ten different peening schedules. Among the investigated processes, the usage of 0.8 mm diameter cast steel shot followed by a second peening with 0.3 mm diameter cast steel shot leads to optimal performance, regarding fatigue life. X-ray diffraction analysis shows that this improved performance may be attributed to residual compressive stress maintained until a depth of 0.02 mm below the surface, which directly influences fatigue crack nucleation. Residual stresses induced by shot peening in larger depths have no influence on the sample’s fatigue life

  19. Protoplast isolation, transient transformation of leaf mesophyll protoplasts and improved Agrobacterium-mediated leaf disc infiltration of Phaseolus vulgaris: tools for rapid gene expression analysis.

    Science.gov (United States)

    Nanjareddy, Kalpana; Arthikala, Manoj-Kumar; Blanco, Lourdes; Arellano, Elizabeth S; Lara, Miguel

    2016-06-24

    Phaseolus vulgaris is one of the most extensively studied model legumes in the world. The P. vulgaris genome sequence is available; therefore, the need for an efficient and rapid transformation system is more imperative than ever. The functional characterization of P. vulgaris genes is impeded chiefly due to the non-amenable nature of Phaseolus sp. to stable genetic transformation. Transient transformation systems are convenient and versatile alternatives for rapid gene functional characterization studies. Hence, the present work focuses on standardizing methodologies for protoplast isolation from multiple tissues and transient transformation protocols for rapid gene expression analysis in the recalcitrant grain legume P. vulgaris. Herein, we provide methodologies for the high-throughput isolation of leaf mesophyll-, flower petal-, hypocotyl-, root- and nodule-derived protoplasts from P. vulgaris. The highly efficient polyethylene glycol-mannitol magnesium (PEG-MMG)-mediated transformation of leaf mesophyll protoplasts was optimized using a GUS reporter gene. We used the P. vulgaris SNF1-related protein kinase 1 (PvSnRK1) gene as proof of concept to demonstrate rapid gene functional analysis. An RT-qPCR analysis of protoplasts that had been transformed with PvSnRK1-RNAi and PvSnRK1-OE vectors showed the significant downregulation and ectopic constitutive expression (overexpression), respectively, of the PvSnRK1 transcript. We also demonstrated an improved transient transformation approach, sonication-assisted Agrobacterium-mediated transformation (SAAT), for the leaf disc infiltration of P. vulgaris. Interestingly, this method resulted in a 90 % transformation efficiency and transformed 60-85 % of the cells in a given area of the leaf surface. The constitutive expression of YFP further confirmed the amenability of the system to gene functional characterization studies. We present simple and efficient methodologies for protoplast isolation from multiple P

  20. 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)

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  2. Method for continuous measurement of export from a leaf

    International Nuclear Information System (INIS)

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

    1979-01-01

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

  3. Endophytic fungi reduce leaf-cutting ant damage to seedlings

    Science.gov (United States)

    Bittleston, L. S.; Brockmann, F.; Wcislo, W.; Van Bael, S. A.

    2011-01-01

    Our study examines how the mutualism between Atta colombica leaf-cutting ants and their cultivated fungus is influenced by the presence of diverse foliar endophytic fungi (endophytes) at high densities in tropical leaf tissues. We conducted laboratory choice trials in which ant colonies chose between Cordia alliodora seedlings with high (Ehigh) or low (Elow) densities of endophytes. The Ehigh seedlings contained 5.5 times higher endophyte content and a greater diversity of fungal morphospecies than the Elow treatment, and endophyte content was not correlated with leaf toughness or thickness. Leaf-cutting ants cut over 2.5 times the leaf area from Elow relative to Ehigh seedlings and had a tendency to recruit more ants to Elow plants. Our findings suggest that leaf-cutting ants may incur costs from cutting and processing leaves with high endophyte loads, which could impact Neotropical forests by causing variable damage rates within plant communities. PMID:20610420

  4. Green synthesis and characterization of silver nanoparticles using Lantana camara leaf extract

    International Nuclear Information System (INIS)

    Ajitha, B.; Ashok Kumar Reddy, Y.; Sreedhara Reddy, P.

    2015-01-01

    In this work, we have investigated on Lantana camara mediated silver nanoparticles (AgNPs) with different leaf extract (LE) quantity for the evaluation of efficient bactericidal activity. The AgNPs were prepared by simple, capable, eco-friendly and biosynthesis method using L. camara LE. This method allowed the synthesis of crystalline nanoparticles, which was confirmed by X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns. The X-ray photoelectron spectroscopy (XPS) analysis confirmed the formation of metallic silver and elucidates the surface state composition of AgNPs. UV–vis spectra of AgNPs and visual perception of brownish yellow color from colorless reaction mixture confirmed the AgNP formation. Involvement of functional groups of L. camara leaf extract in the reduction and capping process of nanoparticles was well displayed in Fourier transform infrared spectroscopy (FTIR). Decrement of particle size with an increment of leaf extract volume was evident in AFM, TEM images and also through a blue shift in the UV–vis spectra. The rate of formation and size of AgNPs were dependent on LE quantity. Meanwhile, these AgNPs exhibited effective antibacterial activity with the decrement of particle size against all tested bacterial cultures. - Highlights: • Monodispersed AgNPs are synthesized using L. camara leaf extract. • The higher the L. camara content, the smaller the particle size. • Green synthesized AgNPs are found to be photoluminescent. • Size dependence of antibacterial activity is reported. • The nanoparticle stability is improved by leaf extract quantity

  5. Green synthesis and characterization of silver nanoparticles using Lantana camara leaf extract

    Energy Technology Data Exchange (ETDEWEB)

    Ajitha, B., E-mail: ajithabondu@gmail.com [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Ashok Kumar Reddy, Y. [Department of Electrical Engineering, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Sreedhara Reddy, P. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India)

    2015-04-01

    In this work, we have investigated on Lantana camara mediated silver nanoparticles (AgNPs) with different leaf extract (LE) quantity for the evaluation of efficient bactericidal activity. The AgNPs were prepared by simple, capable, eco-friendly and biosynthesis method using L. camara LE. This method allowed the synthesis of crystalline nanoparticles, which was confirmed by X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns. The X-ray photoelectron spectroscopy (XPS) analysis confirmed the formation of metallic silver and elucidates the surface state composition of AgNPs. UV–vis spectra of AgNPs and visual perception of brownish yellow color from colorless reaction mixture confirmed the AgNP formation. Involvement of functional groups of L. camara leaf extract in the reduction and capping process of nanoparticles was well displayed in Fourier transform infrared spectroscopy (FTIR). Decrement of particle size with an increment of leaf extract volume was evident in AFM, TEM images and also through a blue shift in the UV–vis spectra. The rate of formation and size of AgNPs were dependent on LE quantity. Meanwhile, these AgNPs exhibited effective antibacterial activity with the decrement of particle size against all tested bacterial cultures. - Highlights: • Monodispersed AgNPs are synthesized using L. camara leaf extract. • The higher the L. camara content, the smaller the particle size. • Green synthesized AgNPs are found to be photoluminescent. • Size dependence of antibacterial activity is reported. • The nanoparticle stability is improved by leaf extract quantity.

  6. Lotus-leaf-like structured chitosan–polyvinyl pyrrolidone films as an anti-adhesion barrier

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jin Ik; Kang, Min Ji; Lee, Woo-Kul, E-mail: leewo@dankook.ac.kr

    2014-11-30

    Highlights: • Improved mechanical properties by hydrogen bond between chitosan and PVP chains. • Improved anti-adhesion effect by lotus-leaf-like structured chitosan–PVP (L-chitosan–PVP) film. • L-Chitosan–PVP film as a blood/tissue anti-adhesion barrier for post-surgical treatment. - Abstract: For postsurgical anti-adhesion barrier applications, lotus-leaf-like structured chitosan–PVP films were prepared using a solution casting method with dodecyltrichloro-immobilized SiO{sub 2} nanoparticles. We evaluated whether the lotus-leaf-like structured chitosan–PVP films (L-chitosan–PVP) could be applied as postsurgical anti-adhesion barriers. A recovery test using a tensile strength testing machine and measurement of crystallinity using X-ray diffraction indicated that films with 75% PVP were the optimal composition of the chitosan–PVP films. Also, dodecyltrichloro-immobilized SiO{sub 2} nanoparticles were synthesized and sprayed on the film after pretreatment with the instant bio-glue. Analysis of cell adhesion, proliferation, and anti-thrombus efficiency were performed via a WST assay, field emission scanning electron microscopy, and hemacytometry. The contact angle with the lotus-leaf-like surface was of approximately 150°. Furthermore, the L-chitosan–PVP film yielded a lower cell and platelet adhesion rate (around less than 4%) than that yielded by the untreated film. These results indicate that the lotus-leaf-like structure has a unique property and that this novel L-chitosan–PVP film can be applied as a blood/tissue-compatible, biodegradable material for implantable medical devices that need an anti-adhesion barrier.

  7. Lotus-leaf-like structured chitosan–polyvinyl pyrrolidone films as an anti-adhesion barrier

    International Nuclear Information System (INIS)

    Lim, Jin Ik; Kang, Min Ji; Lee, Woo-Kul

    2014-01-01

    Highlights: • Improved mechanical properties by hydrogen bond between chitosan and PVP chains. • Improved anti-adhesion effect by lotus-leaf-like structured chitosan–PVP (L-chitosan–PVP) film. • L-Chitosan–PVP film as a blood/tissue anti-adhesion barrier for post-surgical treatment. - Abstract: For postsurgical anti-adhesion barrier applications, lotus-leaf-like structured chitosan–PVP films were prepared using a solution casting method with dodecyltrichloro-immobilized SiO 2 nanoparticles. We evaluated whether the lotus-leaf-like structured chitosan–PVP films (L-chitosan–PVP) could be applied as postsurgical anti-adhesion barriers. A recovery test using a tensile strength testing machine and measurement of crystallinity using X-ray diffraction indicated that films with 75% PVP were the optimal composition of the chitosan–PVP films. Also, dodecyltrichloro-immobilized SiO 2 nanoparticles were synthesized and sprayed on the film after pretreatment with the instant bio-glue. Analysis of cell adhesion, proliferation, and anti-thrombus efficiency were performed via a WST assay, field emission scanning electron microscopy, and hemacytometry. The contact angle with the lotus-leaf-like surface was of approximately 150°. Furthermore, the L-chitosan–PVP film yielded a lower cell and platelet adhesion rate (around less than 4%) than that yielded by the untreated film. These results indicate that the lotus-leaf-like structure has a unique property and that this novel L-chitosan–PVP film can be applied as a blood/tissue-compatible, biodegradable material for implantable medical devices that need an anti-adhesion barrier

  8. GOLD IS EARNED FROM THE PRODUCTION OF THAI GOLD LEAF

    Directory of Open Access Journals (Sweden)

    Dirk Bax

    2010-06-01

    Full Text Available Thai people like to cover sacred objects or things dear to them with gold leaf.. Statues of Buddha are sometimes covered with so many layers of gold leaf that they become formless figures, that can hardly be recognized. Portraits of beloved ancestors, statues of elephants and grave tombs are often covered with gold leaf. If one considers the number of Thai people and the popularity of the habit, the amount of gold involved could be considerable.

  9. Generality of leaf trait relationships: A test across six biomes

    Energy Technology Data Exchange (ETDEWEB)

    Reich, P.B. [Univ. of Minnesota, Saint Paul, MN (United States). Dept. of Forest Resources; Ellsworth, D.S. [Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science; Walters, M.B. [Michigan State Univ., East Lansing, MI (United States). Dept. of Forestry; Vose, J.M. [Forest Service, Otto, NC (United States). Coweeta Hydrological Lab.; Gresham, C. [Clemson Univ., Georgetown, SC (United States). Baruch Forest Inst.; Volin, J.C. [Florida Atlantic Univ., Davie, FL (United States). Div. of Science; Bowman, W.D. [Inst. of Arctic and Alpine Research, Boulder, CO (United States). Mountain Research Station]|[Univ. of Colorado, Boulder, CO (United States). Dept. of Evolutionary, Population, and Organismic Biology

    1999-09-01

    Convergence in interspecific leaf trait relationships across diverse taxonomic groups and biomes would have important evolutionary and ecological implications. Such convergence has been hypothesized to result from trade-offs that limit the combination of plant traits for any species. Here the authors address this issue by testing for biome differences in the slope and intercept of interspecific relationships among leaf traits: longevity, net photosynthetic capacity (A{sub max}), leaf diffusive conductance (G{sub S}), specific leaf area (SLA), and nitrogen (N) status, for more than 100 species in six distinct biomes of the Americas. The six biomes were: alpine tundra-subalpine forest ecotone, cold temperate forest-prairie ecotone, montane cool temperate forest, desert shrubland, subtropical forest, and tropical rain forest. Despite large differences in climate and evolutionary history, in all biomes mass-based leaf N (N{sub mass}), SLA, G{sub S}, and A{sub max} were positively related to one another and decreased with increasing leaf life span. The relationships between pairs of leaf traits exhibited similar slopes among biomes, suggesting a predictable set of scaling relationships among key leaf morphological, chemical, and metabolic traits that are replicated globally among terrestrial ecosystems regardless of biome or vegetation type. However, the intercept (i.e., the overall elevation of regression lines) of relationships between pairs of leaf traits usually differed among biomes. With increasing aridity across sites, species had greater A{sub max} for a given level of G{sub S} and lower SLA for any given leaf life span. Using principal components analysis, most variation among species was explained by an axis related to mass-based leaf traits (A{sub max}, N, and SLA) while a second axis reflected climate, G{sub S}, and other area-based leaf traits.

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

    Directory of Open Access Journals (Sweden)

    L.G. Aribal

    2017-12-01

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

  11. Silver nano fabrication using leaf disc of Passiflora foetida Linn

    Science.gov (United States)

    Lade, Bipin D.; Patil, Anita S.

    2017-06-01

    The main purpose of the experiment is to develop a greener low cost SNP fabrication steps using factories of secondary metabolites from Passiflora leaf extract. Here, the leaf extraction process is omitted, and instead a leaf disc was used for stable SNP fabricated by optimizing parameters such as a circular leaf disc of 2 cm (1, 2, 3, 4, 5) instead of leaf extract and grade of pH (7, 8, 9, 11). The SNP synthesis reaction is tried under room temperature, sun, UV and dark condition. The leaf disc preparation steps are also discussed in details. The SNP obtained using (1 mM: 100 ml AgNO3+ singular leaf disc: pH 9, 11) is applied against featured room temperature and sun condition. The UV spectroscopic analysis confirms that sun rays synthesized SNP yields stable nano particles. The FTIR analysis confirms a large number of functional groups such as alkanes, alkyne, amines, aliphatic amine, carboxylic acid; nitro-compound, alcohol, saturated aldehyde and phenols involved in reduction of silver salt to zero valent ions. The leaf disc mediated synthesis of silver nanoparticles, minimizes leaf extract preparation step and eligible for stable SNP synthesis. The methods sun and room temperature based nano particles synthesized within 10 min would be use certainly for antimicrobial activity.

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

    African Journals Online (AJOL)

    use

    2011-11-21

    Nov 21, 2011 ... discontinuous variation for leaf shape in F2 generations of three crosses .... Variable classes in leaf types (a) Normal leaf (b) Okra leaf (c) Sub-okra leaf. ..... insect pests on different isogenic lines of cotton variety H-777. J.

  13. Fire in Australian savannas: from leaf to landscape

    Science.gov (United States)

    Beringer, Jason; Hutley, Lindsay B; Abramson, David; Arndt, Stefan K; Briggs, Peter; Bristow, Mila; Canadell, Josep G; Cernusak, Lucas A; Eamus, Derek; Edwards, Andrew C; Evans, Bradley J; Fest, Benedikt; Goergen, Klaus; Grover, Samantha P; Hacker, Jorg; Haverd, Vanessa; Kanniah, Kasturi; Livesley, Stephen J; Lynch, Amanda; Maier, Stefan; Moore, Caitlin; Raupach, Michael; Russell-Smith, Jeremy; Scheiter, Simon; Tapper, Nigel J; Uotila, Petteri

    2015-01-01

    Savanna ecosystems comprise 22% of the global terrestrial surface and 25% of Australia (almost 1.9 million km2) and provide significant ecosystem services through carbon and water cycles and the maintenance of biodiversity. The current structure, composition and distribution of Australian savannas have coevolved with fire, yet remain driven by the dynamic constraints of their bioclimatic niche. Fire in Australian savannas influences both the biophysical and biogeochemical processes at multiple scales from leaf to landscape. Here, we present the latest emission estimates from Australian savanna biomass burning and their contribution to global greenhouse gas budgets. We then review our understanding of the impacts of fire on ecosystem function and local surface water and heat balances, which in turn influence regional climate. We show how savanna fires are coupled to the global climate through the carbon cycle and fire regimes. We present new research that climate change is likely to alter the structure and function of savannas through shifts in moisture availability and increases in atmospheric carbon dioxide, in turn altering fire regimes with further feedbacks to climate. We explore opportunities to reduce net greenhouse gas emissions from savanna ecosystems through changes in savanna fire management. PMID:25044767

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  15. Characterization of leaf area of Agave fourcroydes Lem. plants obtained from asexual propagation

    Directory of Open Access Journals (Sweden)

    Maryla Sosa del Castillo

    2014-01-01

    Full Text Available The henequen (Agave fourcroydes Lem. is a crop of great economic importance. This study was aimed to characterize the leaf surface of henequen plants variety `Sac Ki' obtained by asexual propagation methods. In vitro plants, shoots of bulbils of in vitro plants, shoots of rhizomes of in vitro plants, shoots of bulbils of field plants and shoots of field rhizomes were used. At 7 and 15 months after planting in the nursery, the epidermis was characterized through the stomatal index and stomatal density. Moreover, the conductor vessels and fiber bundles in leaf mesophyll, were characterized. It was found that the leaf surface of henequen plants variety `Sac Ki' obtained by different methods of asexual propagation showed similar anatomical structures. However, it was observed that in vitro plants were different from the rest in terms of stomatal index and stomatal density in both time points. It was suggesting a accommodate response to environmental conditions. Key words: stomatic density, stomatic index, in vitro plants

  16. Nanofibers-based nanoweb promise superhydrophobic polyaniline: from star-shaped to leaf-shaped structures.

    Science.gov (United States)

    Fan, Haosen; Wang, Hao; Guo, Jing; Zhao, Ning; Xu, Jian

    2013-11-01

    Star-shaped and leaf-shaped polyaniline (PANI) hierarchical structures with interlaced nanofibers on the surface were successfully prepared by chemical polymerization of aniline in the presence of lithium triflate (LT). Chemical structure and composition of the star-like PANI obtained were characterized by FTIR and UV-vis spectra. PANI 2D architectures can be tailored from star-shaped to leaf-shaped structures by change the concentration of LT. The synthesized star-like and leaf-like polyaniline show good superhydrophobicity with water contact angles of both above 150° due to the combination of the rough nanoweb structure and the low surface tension of fluorinated chain of dopant. This method is a facile and applicable strategy for a large-scale fabrication of 2D PANI micro/nanostructures. Many potential applications such as self-cleaning and antifouling coating can be expected based on the superhydrophobic PANI micro/nanostructures. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

  17. Allelopathic potential of Rapanea umbellata leaf extracts.

    Science.gov (United States)

    Novaes, Paula; Imatomi, Maristela; Varela, Rosa M; Molinillo, José M G; Lacret, Rodney; Gualtieri, Sonia C J; Macías, Francisco A

    2013-08-01

    The stressful conditions associated with the Brazilian savanna (Cerrado) environment were supposed to favor higher levels of allelochemicals in Rapanea umbellata from this ecosystem. The allelopathic potential of R. umbellata leaf extracts was studied using the etiolated wheat coleoptile and standard phytotoxicity bioassays. The most active extract was selected to perform a bioassay-guided isolation, which allowed identifying lutein (1) and (-)-catechin (2) as potential allelochemicals. Finally, the general bioactivity of the two compounds was studied, which indicated that the presence of 1 might be part of the defense mechanisms of this plant. Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.

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

    NARCIS (Netherlands)

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

    1999-01-01

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

  19. Leaf nutrient contents and morphology of invasive tamarisk in different soil conditions in the lower Virgin River

    Science.gov (United States)

    Imada, S.; Acharya, K.; Tateno, R.; Yamanaka, N.

    2012-12-01

    Invasive plants can alter ecosystem nitrogen (N) cycling. To increase our understanding of nutrient use strategy of invasive tamarisk (Tamarix spp.) on an arid riparian ecosystem, we examined leaf nutrient contents and morphology of Tamarix ramosissima and its relationship with soil properties in the lower Virgin River floodplain, Nevada, U.S. Leaves were collected in three different locations; near the river, near the stand edge (60-70 m from the river edge) and at 30-40 m from the river edge in the summer of 2011. Leaves were analyzed for carbon (C) and N contents, and specific leaf area (SLA). Soil samples at 10-20 cm depths and under the canopy were also collected for soil water, pH, electrical conductivity (EC) and inorganic nitrogen (NO3- and NH4+) analysis. Results suggested that tree size and SLA increased with decreasing distance from the river, whereas C isotope discrimination did not differ among the samples based on distance from the river. Nitrogen content per unit mass and N isotope discrimination (δ15N) were significantly higher in the trees near the river. Soil NO3- and total inorganic N had positive relationships with δ15N in leaves, which suggests that leaf δ15N may be influenced by N concentrations on the soil surface. Negative correlations were found between soil EC and leaf N contents, suggesting that high soil salinity may decrease Tamarix leaf N and thus limit tree growth.

  20. Gene expression in response to Cotton Leaf Curl Virus infection in Gossypium hirsutum under variable environmental conditions

    Directory of Open Access Journals (Sweden)

    Rehman Iqra

    2017-01-01

    Full Text Available Cotton Leaf Curl Disease (CLCuD is one of the threatening constrains of cotton production in Pakistan for which no adequate remedy is available until now. Local variety of Gossypium hirsutum (FH-142 was grown in field and infected naturally by CLCuV under variable range of temperature and humidity. Plants showed thickening of veins in lower leaf surface at 34°C and 60% relative humidity at 15days post infection (dpi and curling of leaf margins at 33°C with 58% relative humidity at 30dpi. Remarkable leaf darkening was observed with reduced boll formation at 45dpi at 26°C and 41% relative humidity. Enation developed, severe thickening and curling of leaves intensified and plants showed dwarf growth at 60dpi at 24°C with 52% relative humidity. PCR amplification of Rep associated gene confirmed the presence of CLCuD-associated begomovirus in the infected samples. Quantitative RT-PCR confirmed the amplification and differential expression of a number of pathogen stress responsive genes at different levels of temperature and humidity. This observation predicts that Cotton Leaf Curl Virus (CLCuV interacts with several host genes that are upregulated to make plants susceptible or suppress other genes to overcome host defense responses.

  1. Ultraviolet-B radiation influences the abundance and distribution of phylloplane fungi on pedunculate oak (Quercus robur)

    International Nuclear Information System (INIS)

    Newsham, K.K.; Low, M.N.R.; McLeod, A.R.; Greenslade, P.D.; Emmett, B.A.

    1997-01-01

    The effects of u.v.-B radiation (280-315 nm) on the fungi occurring on the lammas leaves of pedunculate oak (Quercus robur L.) were examined using saplings that were exposed at an outdoor facility to supplemental levels of u.v.-B radiation under treatment arrays of cellulose diacetate-filtered fluorescent lamps, which also produce u.v.-A radiation (315-400 nm). Saplings were also exposed to u.v.-A radiation alone under control arrays of polyester-filtered lamps, and to ambient levels of solar radiation under arrays of unenergized lamps. The u.v.-B treatment corresponded to a 30% elevation above the ambient level of erythemally-weighted u.v.-B radiation. The fungi were examined weekly over a 4-month-period in summer and autumn 1995 using two techniques, the spore fall and leaf impression methods, which differentiated between those fungi occurring on the upper (adaxial) and lower (abaxial) surfaces of the leaves. The abundances of Aureobasidium pullulans (De Bary) Arnaud and Sporobolomyces roseus Kluy. et van Niel, two leaf yeasts which had adaxial:abaxial ratios of < 1 under ambient levels of u.v.-B radiation, were negatively correlated with increasing ambient levels of u.v.-B radiation and were significantly reduced on adaxial leaf surfaces by supplemental levels of u.v.-B. There were few effects of supplemental u.v.-B radiation on the abundances of these yeasts on abaxial leaf surfaces. The abundances of the dematiaceous hyphomycetes, Cladosporium spp. and Epicoccum nigrum Link., species with adaxial:abaxial ratios of ⩾ 1 under ambient levels of u.v.-B radiation, were not correlated with ambient levels of u.v.-B radiation, nor were they usually affected on either leaf surface by supplemental u.v.-B radiation. Alternaria spp. and Microdochium nivale (Fr.) Samuels & Hallet showed consistent responses on adaxial leaf surfaces to u.v.-A radiation applied under control and treatment arrays. Our results suggest that current levels of shortwave radiation already

  2. 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.

  3. Leaf litter and roots as sources of mineral soil organic matter in temperate deciduous forest with and without earthworms

    Science.gov (United States)

    Fahey, T.; Yavitt, J. B.

    2012-12-01

    We labeled sugar maple trees with 13C to quantify the separate contributions of decaying leaf litter and root turnover/rhizosphere C flux to mineral soil organic matter (SOM). Labeled leaf litter was applied to forest plots with and without earthworms and recovery of the label in SOM was quantified over three years. In parallel, label recovery was quantified in soils from the labeling chambers where all label was supplied by belowground C flux. In the absence of earthworms about half of the label added as leaf litter remained in the surface organic horizons after three years, with about 3% recovered in mineral SOM. The label was most enriched on silt + clay surfaces, representing precipitation of DOC derived from litter. Earthworms mixed nearly all the leaf litter into mineral soil within one year, and after two years the label was most enriched in particulate organic matter held within soil aggregates produced by worms. After three years 15-20% of the added label was recovered in mineral SOM. In the labeling chambers over 75% of belowground C allocation (BCA) was used in root and rhizosphere respiration in the first year after labeling. We recovered only 3.8% of estimated BCA in SOM after 3 years; however, expressed as a proportion of fine root production plus rhizosphere C flux, this value is 15.4%, comparable to that for leaf litter in the presence of earthworms. In conclusion, both roots and leaf litter contribute significantly to the formation of stabilized mineral SOM in temperate deciduous forests, and this process is profoundly altered by the invasion of lumbricid earthworms.

  4. Antioxidant capacity, insecticidal ability and heat-oxidation stability of Tagetes lemmonii leaf extract.

    Science.gov (United States)

    Ma, Chih-Ming; Cheng, Chih-Lun; Lee, Shang-Chieh; Hong, Gui-Bing

    2018-04-30

    The aim of this study was to examine the effect of process factors such as ethanol concentration, extraction time and temperature on the extraction yield and the bioactive contents of Tagetes lemmonii leaf extracts using response surface methodology (RSM). ANOVA results showed that the response variables were affected by the ethanol concentration to a very significant degree and by extraction temperature to a lesser degree. GC/MS characterization showed that the extract is rich in bioactive compounds and those present exhibited important biological activities such as antioxidant, insect repellence and insecticidal activities. The results from the toxicity assay demonstrate that the extract obtained from the leaves of Tagetes lemmonii was an effective insect toxin against Tribolium castaneum. The radical scavenging activity and p-anisidine test results of olive oil spiked with different concentrations of leaf extract showed that the phenolic compounds can retard lipid oxidation. Copyright © 2018 Elsevier Inc. All rights reserved.

  5. Release Profile of Andrographis paniculata Leaf Extract Nanocapsule as α-Glucosidase Inhibitors

    Science.gov (United States)

    Zahrani, K.; Imansari, F.; Utami, T. S.; Arbianti, R.

    2017-07-01

    Andrographis paniculata is one of 13 leading commodities Indonesian medicinal plants through the Ditjen POM. Andrographolide as main active compound has been shown to have many pharmacological activities, one of which is as α-glucosidase enzyme inhibitors which has clinical potential as an antitumor, antiviral, antidiabetic, and immunoregulator agents. This study aims to do nanoencapsulation of Andrographis paniculatar leaf extract to increase its active compound bioavailability and get a release profile through synthetic fluids media simulation. Nanoencapsulation with ionic gelation method result the encapsulation efficiency and loading capacity values of 73.47% and 46.29% at 2%: 1% of chitosan: STPP ratio. The maximum α-glucosidase inhibition of 37.17% was obtained at 16% concentration. Burst release at gastric pH conditions indicate that most of the drug (in this study is an Andrographis paniculata leaf extract) adsorbed on the surface of the nanoparticles an indicates that the kind of nanoparticle formed is nanosphere.

  6. Optimization of the carrot leaf dehydration aiming at the preservation of omega-3 fatty acids

    Directory of Open Access Journals (Sweden)

    Vanessa Vivian de Almeida

    2009-01-01

    Full Text Available The carrot leaf dehydration conditions in air circulation oven were optimized through response surface methodology (RSM for minimizing the degradation of polyunsaturated fatty acids, particularly alpha-linolenic (LNA, 18:3n-3. The optimized leaf drying time and temperature were 43 h and 70 ºC, respectively. The fatty acids (FA were investigated using gas chromatography equipped with a flame ionization detector and fused silica capillary column; FA were identified with standards and based on equivalent-chain-length. LNA and other FA were quantified against C21:0 internal standard. After dehydration, the amount of LNA, quantified in mg/100 g dry matter of dehydrated carrot leaves, were 984 mg.

  7. Synthesis, characterization and catalytic activity of silver nanoparticles using Tribulus terrestris leaf extract.

    Science.gov (United States)

    Ashokkumar, S; Ravi, S; Kathiravan, V; Velmurugan, S

    2014-01-01

    Biomediated silver nanoparticles were synthesized with the aid of an eco-friendly biomaterial, namely, aqueous Tribulus terrestris extract. Silver nanoparticles were synthesized using a rapid, single step, and completely green biosynthetic method employing aqueous T. terrestris leaf extracts as both the reducing and capping agent. Silver ions were rapidly reduced by aqueous T. terrestris leaf extracts, leading to the formation of highly crystalline silver nanoparticles. An attempt has been made and formation of the silver nanoparticles was verified by surface plasmon spectra using an UV-vis (Ultra violet), spectrophotometer. Morphology and crystalline structure of the prepared silver nanoparticles were characterized by TEM (Transmission Electron Microscope) and XRD (X-ray Diffraction), techniques, respectively. FT-IR (Fourier Transform Infrared), analysis suggests that the obtained silver nanoparticles might be stabilized through the interactions of carboxylic groups, carbonyl groups and the flavonoids present in the T. terrestris extract. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Estimating leaf photosynthetic pigments information by stepwise multiple linear regression analysis and a leaf optical model

    Science.gov (United States)

    Liu, Pudong; Shi, Runhe; Wang, Hong; Bai, Kaixu; Gao, Wei

    2014-10-01

    Leaf pigments are key elements for plant photosynthesis and growth. Traditional manual sampling of these pigments is labor-intensive and costly, which also has the difficulty in capturing their temporal and spatial characteristics. The aim of this work is to estimate photosynthetic pigments at large scale by remote sensing. For this purpose, inverse model were proposed with the aid of stepwise multiple linear regression (SMLR) analysis. Furthermore, a leaf radiative transfer model (i.e. PROSPECT model) was employed to simulate the leaf reflectance where wavelength varies from 400 to 780 nm at 1 nm interval, and then these values were treated as the data from remote sensing observations. Meanwhile, simulated chlorophyll concentration (Cab), carotenoid concentration (Car) and their ratio (Cab/Car) were taken as target to build the regression model respectively. In this study, a total of 4000 samples were simulated via PROSPECT with different Cab, Car and leaf mesophyll structures as 70% of these samples were applied for training while the last 30% for model validation. Reflectance (r) and its mathematic transformations (1/r and log (1/r)) were all employed to build regression model respectively. Results showed fair agreements between pigments and simulated reflectance with all adjusted coefficients of determination (R2) larger than 0.8 as 6 wavebands were selected to build the SMLR model. The largest value of R2 for Cab, Car and Cab/Car are 0.8845, 0.876 and 0.8765, respectively. Meanwhile, mathematic transformations of reflectance showed little influence on regression accuracy. We concluded that it was feasible to estimate the chlorophyll and carotenoids and their ratio based on statistical model with leaf reflectance data.

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

    Science.gov (United States)

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

    2018-05-01

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

  10. The surface learned from nature

    Science.gov (United States)

    Lim, H.; Kim, W. D.

    2010-07-01

    In this work, I would like to introduce the emerging surface of nature. The surface in nature, has the multi and optimized function with well organized structure. There are so many examples that we learn and apply to technology. First example is self-cleaning surface. Some plants (such as lotus leaf, taro leaf) and the wings of many large-winged insects (such as moth, butterfly, dragonfly) remain their surface clean in the very dirty environment. This self cleaning effect is accomplished by the superhydrophobic surfaces which exhibit the water contact angle of more than 150° with low sliding angle. Generally, the superhydrophobic surface is made up the two factors. One is the surface composition having the low surface tension energy. The other is the surface morphology of hierarchical structure of micro and nano size. Because almost nature surface have the hierarchical structures range from macro to nano size, their topography strength their function to adjust the life in nature environment. The other example is the surface to use for drag reduction. The skin friction drag causes eruptions of air or water resulting in greater drag as the speed is increased. This drag requires more energy to overcome. The shark skin having the fine sharp-edged grooves about 0.1 mm wide known riblet reduces in skin friction drag by being far away the vortex. Among a lot of fuctional surface, the most exciting surface the back of stenocara a kind of desert beetles. Stenocara use the micrometre-sized patterns of hydrophobic, wax-coated and hydrophilic, non-waxy regions on their backs to capture water from fog. This fog-collecting structure improves the water collection of fog-capture film, condenser, engine, and future building. Here, the efforts to realize these emerging functional surfaces in nature on technology are reported with the fabrication method and their properties, especially for the control of surface wettability.

  11. Leaf cuticles as mediators of environmental influences: new developments in the use of isolated cuticles

    International Nuclear Information System (INIS)

    Scherbatskoy, T.

    1994-01-01

    Isolated leaf cuticles have been used in our research to characterize trans-cuticular ion diffusion rates under various environmental treatments and to measure cuticular attenuation of solar radiation. These studies have been conducted to understand better the role of the leaf cuticle as a protective barrier against potential environmental stressors including acid rain, ozone and ultraviolet radiation. These studies provide examples of a variety of current research uses for isolated leaf cuticles. Ion permeability coefficients and exchange rates in isolated cuticles of Acer, Prunus and Citrus species have been studied using several experimental approaches, including measurement of adsorption kinetics, electrical potential and conductance, and perfusion rates. Measured electrical (diffusion) potentials under KCl gradients across isolated cuticles are positive, indicating greater cation permeability. Electrical potentials (and permeability coefficients) vary with ionic strength and pH, and affect the driving force for ion diffusion through cuticles. Ion permeability in cuticles of Prunus serotina foliage was affected by experimental exposure to ozone and ultraviolet treatments. These studies indicate that cuticle permeability properties can be significantly altered by environmental factors. These and related studies on the ion exchange kinetics of Acer saccharum leaf cuticles suggest that foliar ''leaching'' is dominated by cuticle surface exchange mechanisms, with the magnitude of cuticular ion permeation being relatively small. In working with various hardwood species, we observed that the success rate for cuticle isolation varies with tree species and time of year. Scanning electron micrographs of inner cuticle surfaces indicate that the effects of enzymatic digestion could vary with exposure time, possibly affecting transport properties of isolated cuticles. Experimental work to test this in Citrus, however, showed no significant effect of isolation time on

  12. Estimation of Leaf Area Index and its Sunlit Portion from DSCOVR EPIC data

    Science.gov (United States)

    Knyazikhin, Y.; Yang, B.; Mottus, M.; Rautiainen, M.; Stenberg, P.; Yan, L.; Chen, C.; Yan, K.; Park, T.; Myneni, R. B.; Song, W.

    2016-12-01

    The NASA's Earth Polychromatic Imaging Camera (EPIC) onboard NOAA's Deep Space Climate Observatory (DSCOVR) mission was launched on February 11, 2015 to the Sun-Earth Lagrangian L1 point where it began to collect radiance data of the entire sunlit Earth at 16 km resolution (in equatorial zone) every 65 to 110 min in June 2015. It provides imageries in near backscattering directions with the scattering angle between 168o and 176o at ten UV to Near-IR narrow spectral bands centered at 317.5 (band width 1.0) nm, 325.0 (1.0) nm, 340.0 (3.0) nm, 388.0 (3.0) nm, 433.0 (3.0) nm, 551.0 (3.0) nm, 680.0 (1.7) nm, 687.8 (0.6) nm, 764.0 (1.7) nm and 779.5 (2.0) nm. This poster presents the theoretical basis of the algorithm designed for the generation of leaf area index (LAI) and diurnal course of sunlit leaf area index (SLAI) from EPIC Bidirectional Reflectance Factor of vegetated land. LAI and SLAI are defined as the total hemi-surface and sunlit leaf semi-surface per unit ground area. Whereas LAI is a standard product of many satellite the SLAI is a new satellite-derived parameter. Sunlit and shaded leaves exhibit different radiative response to incident Photosynthetically Active Radiation (400-700 nm), which in turn triggers various physiological and physical processes required for the functioning of plants. Leaf area and its sunlit portion are key state parameters in most ecosystem productivity and carbon/nitrogen cycle. Status of the EPIC LAI/SLAI product and its validation strategy are also discussed in this poster.

  13. BREEAM Green Leaf Eco-rating Program

    International Nuclear Information System (INIS)

    2001-01-01

    The environmental performance of buildings is measured for several reasons, the main one being that it can help owners decide where to invest their retrofit dollars to maximize the energy performance of their building and reduce operating costs. The buildings constructed in the 1950s and 1960s in North America are reaching obsolescence and will require major retrofits to improve their energy efficiency, particularly in the area of mechanical equipment. In addition to reducing operating costs, better maintenance and environmental management of buildings can also address issues such as comfort, health, indoor air quality and productivity. In order to accurately measure the environmental performance of a building, it is necessary to develop a comprehensive measuring and benchmarking tool that would allow occupants to compare the buildings' performance with others. In this pilot study, 6 high-rise multi-residential buildings were assessed for environmental performance using the BREEAM Green Leaf assessment method. The methodology originated in Canada and was developed by ECD Energy, Environment Canada and Terra Choice. It combines the BREEAM set of environmental issues with the Green Leaf Eco-Rating technique. The method covers occupant health, energy efficiency, resource efficiency, environmental responsibility and affordability. Operation and management issues are also taken into consideration. The buildings used in this study were located in various locations, ranging from inner city housing to city/suburban areas. 2 tabs., 17 figs

  14. Sorption of lead from aqueous solutions by spent tea leaf | Yoshita ...

    African Journals Online (AJOL)

    Pb) from solution. The Pb removal by the spent tea leaf adsorbent depended on pretreatment of spent tea leaf, adsorption contact time and adsorbent dosage. The optimum pretreatment conditions were confirmed to be that tea leaf was ground ...

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2012-05-21

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

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

    Science.gov (United States)

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

    2008-01-01

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

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

    African Journals Online (AJOL)

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

  19. Ozone exposure affects leaf wettability and tree water balance

    NARCIS (Netherlands)

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

    2001-01-01

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

  20. Suppressors of RNA silencing encoded by tomato leaf curl

    Indian Academy of Sciences (India)

    Whitefly-transmitted begomoviruses infecting tomato crop code for five different proteins, ORF AC4, ORF AC2 and ORF AV2 in DNA-A component, ORF BV1 in DNA-B ... In the present study suppressor function of ORF C1 of three betasatellites Tomato leaf curl Bangalore betasatellite ToLCBB-[IN:Hess:08], Cotton leaf curl ...

  1. Ontogeny of the sheathing leaf base in maize (Zea mays).

    Science.gov (United States)

    Johnston, Robyn; Leiboff, Samuel; Scanlon, Michael J

    2015-01-01

    Leaves develop from the shoot apical meristem (SAM) via recruitment of leaf founder cells. Unlike eudicots, most monocot leaves display parallel venation and sheathing bases wherein the margins overlap the stem. Here we utilized computed tomography (CT) imaging, localization of PIN-FORMED1 (PIN1) auxin transport proteins, and in situ hybridization of leaf developmental transcripts to analyze the ontogeny of monocot leaf morphology in maize (Zea mays). CT imaging of whole-mounted shoot apices illustrates the plastochron-specific stages during initiation of the basal sheath margins from the tubular disc of insertion (DOI). PIN1 localizations identify basipetal auxin transport in the SAM L1 layer at the site of leaf initiation, a process that continues reiteratively during later recruitment of lateral leaf domains. Refinement of these auxin transport domains results in multiple, parallel provascular strands within the initiating primordium. By contrast, auxin is transported from the L2 toward the L1 at the developing margins of the leaf sheath. Transcripts involved in organ boundary formation and dorsiventral patterning accumulate within the DOI, preceding the outgrowth of the overlapping margins of the sheathing leaf base. We suggest a model wherein sheathing bases and parallel veins are both patterned via the extended recruitment of lateral maize leaf domains from the SAM. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  2. Timing and duration of autumn leaf development in Sweden

    Science.gov (United States)

    Bolmgren, Kjell

    2014-05-01

    The growing season is changing in both ends and autumn phases seem to be responding in more diverse ways than spring events. Indeed, we know little about autumn leaf phenological strategies and how they are correlated with fitness components or ecosystem properties, and how they vary between species and over bioclimatic gradients. In this study more than 10 000 students were involved in observing autumn leaf development at 378 sites all over Sweden (55-68°N). They followed an image based observation protocol classifying autumn leaf development into five levels, from summer green (level 0) to 100% autumn leaf colored (level 4) canopy. In total, they submitted almost 12 000 observations between August 9 and November 15. 75% of the observations were made on the common species of Populus tremula, Betula pendula/pubescens and Sorbus aucuparia. The expected (negative) correlation between latitude and start of leaf senescence (level 2) was found in Populus and Betula, but not in Sorbus. The duration of the leaf senescence period, defined as the period between 1/3 (level 2) and 100% (level 4) of the canopy autumn leaf colored, was negatively correlated with latitude in Populus and Betula, but not in Sorbus. There was also a strong (negative) correlation of the start (level 2) and the duration of the leaf senescence in the early senescing Sorbus and Betula, while this effect was weaker in the late senescing Populus.

  3. 7 CFR 29.2662 - Heavy Leaf (B Group).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Heavy Leaf (B Group). 29.2662 Section 29.2662 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.2662 Heavy Leaf (B Group). This group consists of leaves...

  4. 7 CFR 29.2438 - Thin Leaf (C Group).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Thin Leaf (C Group). 29.2438 Section 29.2438... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.2438 Thin Leaf (C Group). This group consists of leaves... body than those of the B group, and show little or no ground injury. Choice- and fine-quality tobacco...

  5. 7 CFR 29.2437 - Heavy Leaf (B Group).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Heavy Leaf (B Group). 29.2437 Section 29.2437... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.2437 Heavy Leaf (B Group). This group consists of leaves..., are heavier in body than those of the X or C groups, and show no ground injury. Choice- and fine...

  6. 7 CFR 29.1163 - Smoking Leaf (H Group).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Smoking Leaf (H Group). 29.1163 Section 29.1163... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.1163 Smoking Leaf (H Group). This group consists of leaves normally grown at or above the midportion of the stalk. Leaves of the H group show a high degree...

  7. 7 CFR 29.1162 - Leaf (B Group).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf (B Group). 29.1162 Section 29.1162 Agriculture... INSPECTION Standards Grades § 29.1162 Leaf (B Group). This group consists of leaves normally grown at or above the midportion of the stalk. Leaves of the B group have a pointed tip, tend to fold, usually are...

  8. Evaluation of Microdesmis puberula leaf meal as feed ingredient in ...

    African Journals Online (AJOL)

    The material was milled using a hammer mill to produce the leaf meal. Microdesmis puberula leaf meal contain 17.32% crude protein, 6.52% ether extract, 12.25% total ash, 24.84% crude fibre, 24.06% NFE and an appreciable percent of minerals. Three broiler starter diets were formulated to contain the meal at dietary ...

  9. Antimalarial Anthrone and Chromone from the Leaf Latex of Aloe ...

    African Journals Online (AJOL)

    In Ethiopian traditional medicine, the leaf latex of Aloe debranan Chrstian is used for the treatment of several diseases including malaria. In an ongoing search for effective, safe and cheap antimalarial agents from plants, the leaf latex of A. debrana was tested for its in vivo antimalarial activity, in a 4-day suppressive assay ...

  10. The effect of quince leaf ( Cydonia oblonga miller) decoction on ...

    African Journals Online (AJOL)

    Current medical literature lacks any evidence of the protective effects of quince leaf on testes. Therefore, the aim of the present study was to assess the effect of quince (Cydonia oblonga Miller) leaf decoction on testicular injury and impaired spermatogenesis induced by hypercholesterolemia in rabbits. Eleven mature New ...

  11. Leaf gas exchange of mature bottomland oak trees

    Science.gov (United States)

    Rico M. Gazal; Mark E. Kubiske; Kristina F. Connor

    2009-01-01

    We determined how changes in environmental moisture affected leaf gas exchange in Nuttall (Quercus texana Buckley), overcup (Q. lyrata Walt.), and dominant and codominant swamp chestnut (Q. michauxii Nutt.) oak trees in Mississippi and Louisiana. We used canopy access towers to measure leaf level gas...

  12. Modeling the leaf angle dynamics in rice plant.

    Directory of Open Access Journals (Sweden)

    Yonghui Zhang

    Full Text Available The leaf angle between stem and sheath (SSA is an important rice morphological trait. The objective of this study was to develop and validate a dynamic SSA model under different nitrogen (N rates for selected rice cultivars. The time-course data of SSA were collected in three years, and a dynamic SSA model was developed for different main stem leaf ranks under different N rates for two selected rice cultivars. SSA increased with tiller age. The SSA of the same leaf rank increased with increase in N rate. The maximum SSA increased with leaf rank from the first to the third leaf, then decreased from the third to the final leaf. The relationship between the maximum SSA and leaf rank on main stem could be described with a linear piecewise function. The change of SSA with thermal time (TT was described by a logistic equation. A variety parameter (the maximum SSA of the 3rd leaf on main stem and a nitrogen factor were introduced to quantify the effect of cultivar and N rate on SSA. The model was validated against data collected from both pot and field experiments. The relative root mean square error (RRMSE was 11.56% and 14.05%, respectively. The resulting models could be used for virtual rice plant modeling and plant-type design.

  13. Value of Bitter Leaf ( Vernonia amygdalina ) Meal as Feed ...

    African Journals Online (AJOL)

    A 28-day feeding trial was conducted to evaluate the effect of bitter leaf (Vernonia amygdalina) leaf meal as feed ingredient on the performance, feed cost and carcass and organ weights of finisher broilers. The leaves were air dried under room temperature, ground and sieved through a 3 mm mesh to produce the meal.

  14. ( Azadirachta Indica ) Leaf Extracts on the Rot Fungus ( Fusarium ...

    African Journals Online (AJOL)

    The storage lifespan of kola nuts is challenged by the problem of decay of nuts in storage as a result of the attack by the rot fungus (Fusarium spp). The effect of the neem leaf (Azadirachta indica) extracts on the rot fungus was investigated in order to aid extended kola nuts storage. The aqueous and ethanolic leaf extracts of ...

  15. 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.

  16. Incomplete resistance to coffee leaf rust (Hemileia vastatrix)

    NARCIS (Netherlands)

    Eskes, A.B.

    1983-01-01

    Incomplete resistance to coffee leaf rust ( Hemileia vastatrix ) may be of value in obtaining durable resistance, which is of great importance for the perennial coffee crop. Methods were developed to assess incomplete resistance to coffee leaf rust by using illustrated scales

  17. Composition of the Essential Oil of Clausena Suffruticosa Leaf and ...

    African Journals Online (AJOL)

    Purpose: To investigate the essential oil content of Clausena suffruticosa leaf for its in-vitro antibacterial, antifungal and cytotoxic activities. Methods: The essential oil of Clausena suffruticosa leaf was extracted by hydrodistillation using a modified Clevenger-type apparatus and was analyzed by GC-MS using electron impact ...

  18. Evaluation of Jacaranda mimosifolia T. (Stans) leaf meal as ...

    African Journals Online (AJOL)

    The economic benefit analysis indicated that as the leaf meal increased in the diets the cost of production of the broilers decreased. Jacaranda leaf meal could be best utilized at 5.0% level of inclusion though the 7.5% levels broilers attained market size in a recorded time. Animal Production Research Advances Vol.

  19. Effect of temperature on accumulation of chlorophylls and leaf ...

    African Journals Online (AJOL)

    White young shoots from albino tea cultivars have high level of amino acids and are rare and valuable materials for processing green tea. The effects of temperature on leaf colour, accumulation of chlorophylls and leaf ultrastructures of an albino tea cultivar 'Xiaxueya' were investigated. The study showed that the shoot ...

  20. Comparative antimicrobial activities of aloe vera gel and leaf ...

    African Journals Online (AJOL)

    The comparative antimicrobial activities of the gel and leaf of Aloe vera were tested against Staphylococcus aureus, Pseudomonas aeruginosa, Trichophyton mentagraphytes, T. schoeleinii, Microsporium canis and Candida albicans. Ethanol was used for the extraction of the leaf after obtaining the gel from it. Antimicrobial ...

  1. cassava brown streak disease effects on leaf metabolites

    African Journals Online (AJOL)

    USER

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

  2. Coconut leaf bioactivity toward generalist maize insect pests

    Science.gov (United States)

    Tropical plants are often more resistant to insects than temperate plants due to evolution of robust defenses to cope with a more constant insect threat. Coconut (Cocos nucifera L.) has very few chewing leaf feeding insect pests and was tested against two omnivorous leaf feeding caterpillar species,...

  3. Somatic embryogenesis and plant regeneration from leaf explants of ...

    African Journals Online (AJOL)

    An attempt was made to study the somatic embryogenesis and plant regeneration from the in vitro leaf explants of Rumex vesicarius L. a renowned medicinal plant, which belongs to polygonaceae family. Effective in vitro regeneration of R. vesicarius was achieved via young leaf derived somatic embryo cultures.

  4. Soil Characteristics, Microbial Compostion of Plot, Leaf Count and ...

    African Journals Online (AJOL)

    Soil Characteristics, Microbial Compostion of Plot, Leaf Count and Sprout Studies of Cocoyam ( Colocasia [Schott] and Xanthosoma [Schott], Araceae) Collected in Edo State, ... Science, Technology and Arts Research Journal ... Government Areas (LGA) in Edo state and describe them based on leaf count and sprout

  5. Phytochemical constituents and ethnobotany of the leaf extract of ...

    African Journals Online (AJOL)

    The phytochemical screening and ethno botanical importance of the leaf of Vernonia amygdalina Del. were investigated. The secondary metabolites in the leaf were identified to establish a relationship between them and their therapeutic properties. The leaves were sun dried, pulverized and sieved. The resulting powdered ...

  6. Effect Of Walnut Leaf, Coriander And Pomegranate On Blood ...

    African Journals Online (AJOL)

    Mechanism of most of herbal used for diabetes mellitus treatment has not been well defined. This study was performed to investigate hypoglycemic effect of walnut leaf (Juglans regia L.), coriander leaf (Coriandrum sativum L.) or pomegranate seed (Punica granatum L.), and their possible role on pancreatic tissue. Diabetes ...

  7. Nutritive evaluation of Telfairia occidentalis leaf protein concentrate ...

    African Journals Online (AJOL)

    Leaf meal (LM), leaf proteins concentrate (LPC) and LPC residues from Telfairia occidentalis were produced, chemically characterized and the protein quality of the LPC evaluated using rats. Five infant weaning foods were formulated using varying combinations of T. occidentalis LPC and soybean meal. These foods were ...

  8. Antimicrobial activity of the aqueous, methanol and chloroform leaf ...

    African Journals Online (AJOL)

    The minimum inhibitory concentration (MIC) of methanol leaf extract show least activity against Yersinia enterocolitica and Pseudomonas aeruginosa (MIC = 100 mg/ml) and higher activity of MIC at 50 mg/ml against the other bacterial test organisms. The chloroform leaf extract MIC of 100 mg/ml had least activity against ...

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

    Directory of Open Access Journals (Sweden)

    Hu Yang

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

  10. Ultraestructura de bambúes del género Dendrocalamus (Poaceae: Bambusoideae cultivados en Costa Rica II: Dendrocalamus latiflorus var. latiflorus

    Directory of Open Access Journals (Sweden)

    Mayra Montiel

    2006-06-01

    Full Text Available Mediante el microscopio electrónico de barrido se analizaron muestras de lámina foliar, culmo y rama, así como las brácteas del culmo y yemas de las ramas de Dendrocalamus latiflorus var. latiflorus. Se determinó la presencia en la epidermis abaxial de la lámina foliar de dos tipos de papilas céricas, esféricas y alargadas; éstas últimas rodeando los estomas de bajo domo. Sólo en la superficie adaxial de la nervadura central de la lámina foliar aparecen grandes tricomas en forma de gancho. En la zona abaxial de las brácteas del culmo, hay tricomas alargados y delgados similares a los de las brácteas de D. giganteus y las yemas de las ramas están cubiertas por tricomas bicelulares.We used a scanning electron microscope to observe leaf laminae, culms, branches, culm bracts and branch buds of Dendrocalamus latiflorus var. latiflorus grown in Costa Rica. In the abaxial epidermis of the leaf lamina we found two types of ceric papillae, rounded and elongated, the latter surrounding the low dome stomata. Only the adaxial surface of the central nervature (leaf lamina has big hook-sshaped trichomes. In the abaxial zone of the culm bract there are thin elongated trichomes, similar to those from the bract of Dendrocalamus giganteus. The branch buds are covered by bicelular trichomes. Rev. Biol. Trop. 54(Suppl. 2: 51-57. Epub 2006 Dec. 01.

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

    Directory of Open Access Journals (Sweden)

    Córcoles J.I.

    2015-06-01

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

  12. Resistance in winter barley against Ramularia leaf spot

    DEFF Research Database (Denmark)

    Hjortshøj, Rasmus Lund

    Ramularia leaf spot is an emerging disease in barley caused by R. collo-cygni. At present little is known about the resistance mechanisms carried out by the host plant to avoid disease development. Nor is the lifecycle of the fungus or its populations structure fully understood. To gain insight....... fulvum-tomato and S. tritici-wheat in order to find modelsystems to enhance interpretation of results from R. collo-cygni-barley interaction. Results from the mapping showed that resistance to Ramularia leaf spot is controlled by a number of QTL’s, some of which co-locate with other physiological traits....... The populations further segregated for physiological leaf spots, a phenomenon related to the leaf damage imposed by Rubellin, although, resistance to physiological leafspots appeared to come from the Ramularia leaf spot susceptible parent. The toxin assay further supported this result as the genotypes susceptible...

  13. CIRCADIAN CLOCK-ASSOCIATED 1 Inhibits Leaf Senescence in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Yi Song

    2018-03-01

    Full Text Available Leaf senescence is an integral part of plant development, and the timing and progressing rate of senescence could substantially affect the yield and quality of crops. It has been known that a circadian rhythm synchronized with external environmental cues is critical for the optimal coordination of various physiological and metabolic processes. However, the reciprocal interactions between the circadian clock and leaf senescence in plants remain unknown. Here, through measuring the physiological and molecular senescence related markers of several circadian components mutants, we found that CIRCADIAN CLOCK-ASSOCIATED 1 inhibits leaf senescence. Further molecular and genetic studies revealed that CCA1 directly activates GLK2 and suppresses ORE1 expression to counteract leaf senescence. As plants age, the expression and periodic amplitude of CCA1 declines and thus weakens the inhibition of senescence. Our findings reveal an age-dependent circadian clock component of the process of leaf senescence.

  14. Understanding of Leaf Development—the Science of Complexity

    Directory of Open Access Journals (Sweden)

    Robert Malinowski

    2013-06-01

    Full Text Available The leaf is the major organ involved in light perception and conversion of solar energy into organic carbon. In order to adapt to different natural habitats, plants have developed a variety of leaf forms, ranging from simple to compound, with various forms of dissection. Due to the enormous cellular complexity of leaves, understanding the mechanisms regulating development of these organs is difficult. In recent years there has been a dramatic increase in the use of technically advanced imaging techniques and computational modeling in studies of leaf development. Additionally, molecular tools for manipulation of morphogenesis were successfully used for in planta verification of developmental models. Results of these interdisciplinary studies show that global growth patterns influencing final leaf form are generated by cooperative action of genetic, biochemical, and biomechanical inputs. This review summarizes recent progress in integrative studies on leaf development and illustrates how intrinsic features of leaves (including their cellular complexity influence the choice of experimental approach.

  15. Self-cleaning efficiency of artificial superhydrophobic surfaces.

    Science.gov (United States)

    Bhushan, Bharat; Jung, Yong Chae; Koch, Kerstin

    2009-03-03

    The hierarchical structured surface of the lotus (Nelumbo nucifera, Gaertn.) leaf provides a model for the development of biomimetic self-cleaning surfaces. On these water-repellent surfaces, water droplets move easily at a low inclination of the leaf and collect dirt particles adhering to the leaf surface. Flat hydrophilic and hydrophobic, nanostructured, microstructured, and hierarchical structured superhydrophobic surfaces were fabricated, and a systematic study of wettability and adhesion properties was carried out. The influence of contact angle hysteresis on self-cleaning by water droplets was studied at different tilt angles (TA) of the specimen surfaces (3 degrees for Lotus wax, 10 degrees for n-hexatriacontane, as well as 45 degrees for both types of surfaces). At 3 degrees and 10 degrees TA, no surfaces were cleaned by moving water applied onto the surfaces with nearly zero kinetic energy, but most particles were removed from hierarchical structured surfaces, and a certain amount of particles were captured between the asperities of the micro- and hierarchical structured surfaces. After an increase of the TA to 45 degrees (larger than the tilt angles of all structured surfaces), as usually used for industrial self-cleaning tests, all nanostructured surfaces were cleaned by water droplets moving over the surfaces followed by hierarchical and microstructures. Droplets applied onto the surfaces with some pressure removed particles residues and led to self-cleaning by a combination of sliding and rolling droplets. Geometrical scale effects were responsible for superior performance of nanostructured surfaces.

  16. Surviving floods: leaf gas films improve O₂ and CO₂ exchange, root aeration, and growth of completely submerged rice.

    Science.gov (United States)

    Pedersen, Ole; Rich, Sarah Meghan; Colmer, Timothy David

    2009-04-01

    When completely submerged, the leaves of some species retain a surface gas film. Leaf gas films on submerged plants have recently been termed 'plant plastrons', analogous with the plastrons of aquatic insects. In aquatic insects, surface gas layers (i.e. plastrons) enlarge the gas-water interface to promote O₂ uptake when under water; however, the function of leaf gas films has rarely been considered. The present study demonstrates that gas films on leaves of completely submerged rice facilitate entry of O₂ from floodwaters when in darkness and CO₂ entry when in light. O₂ microprofiles showed that the improved gas exchange was not caused by differences in diffusive boundary layers adjacent to submerged leaves with or without gas films; instead, reduced resistance to gas exchange was probably due to the enlarged water-gas interface (cf. aquatic insects). When gas films were removed artificially, underwater net photosynthesis declined to only 20% of the rate with gas films present, such that, after 7 days of complete submergence, tissue sugar levels declined, and both shoot and root growth were reduced. Internal aeration of roots in anoxic medium, when shoots were in aerobic floodwater in darkness or when in light, was improved considerably when leaf gas films were present. Thus, leaf gas films contribute to the submergence tolerance of rice, in addition to those traits already recognized, such as the shoot-elongation response, aerenchyma and metabolic adjustments to O₂ deficiency and oxidative stress. © 2009 The Authors. Journal compilation © 2009 Blackwell Publishing Ltd.

  17. CO2 and temperature effects on leaf area production in two annual plant species

    International Nuclear Information System (INIS)

    Ackerly, D.D.; Coleman, J.S.; Morse, S.R.; Bazzaz, F.A.

    1992-01-01

    The authors studied leaf area production in two annual plant species, Abutilon theophrasti and Amaranthus retroflexus, under three day/night temperature regimes and two concentrations of carbon dioxide. The production of whole-plant leaf area during the first 30 d of growth was analyzed in terms of the leaf initiation rate, leaf expansion, individual leaf area, and, in Amaranthus, production of branch leaves. Temperature and CO 2 influenced leaf area production through effects on the rate of development, determined by the production of nodes on the main stem, and through shifts in the relationship between whole-plant leaf area and the number of main stem nodes. In Abutilon, leaf initiation rate was highest at 38 degree, but area of individual leaves was greatest at 28 degree. Total leaf area was greatly reduced at 18 degree due to slow leaf initiation rates. Elevated CO 2 concentration increased leaf initiation rate at 28 degree, resulting in an increase in whole-part leaf area. In Amaranthus, leaf initiation rate increased with temperature, and was increased by elevated CO 2 at 28 degree. Individual leaf area was greatest at 28 degree, and was increased by elevated CO 2 at 28 degree but decreased at 38 degree. Branch leaf area displayed a similar response to CO 2 , butt was greater at 38 degree. Overall, wholeplant leaf area was slightly increased at 38 degree relative to 28 degree, and elevated CO 2 levels resulted in increased leaf area at 28 degree but decreased leaf area at 38 degree

  18. Microornamentation of leaf chameleons (Chamaeleonidae: Brookesia, Rhampholeon, and Rieppeleon)--with comments on the evolution of microstructures in the Chamaeleonidae.

    Science.gov (United States)

    Riedel, Jendrian; Böhme, Wolfgang; Bleckmann, Horst; Spinner, Marlene

    2015-02-01

    Chameleons (Chamaeleonidae) feature many adaptations to their arboreal lifestyle, including zygodactylous feet, a prehensile tail, and epidermal microstructures. In arboreal tree chameleons, the substrate-contacting site of the feet and tail is covered by microscopic hair-like structures (setae) of 6-20 µm length. Their friction enhancing function has been shown in recent studies. Leaf chameleons and one representative of the tree chameleons (Chamaeleo namaquensis) secondarily have become ground-dwelling. Because leaf chameleons are paraphyletic, one could expect that in the three leaf chameleon genera Brookesia, Rhampholeon, and Rieppeleon and the tree chameleon Ch. namaquensis, epidermis has adapted independently to terrestrial locomotion. Using scanning electron microscopy, we investigated the substrate-contacting surfaces of the feet (subdigital) of 17 leaf chameleon species and five tree chameleon species that have not yet been examined. Additionally, surfaces not involved in locomotion, the flanks (dorsolateral), and scale interstices, were examined. Although the subdigital microstructures in leaf chameleons are more diverse than in tree chameleons, we found some features across the genera. The subdigital microornamentation of Rhampholeon spinosus consists of long thin setae and spines, comparable to those of tree chameleons. All other Rhampholeon species have spines or short but broad setae. Rh. spectrum had tooth-like structures instead of setae. Subdigital scales of Brookesia have either thorns or conical scale-tops in the center and feature honeycomb microstructures. In Rieppeleon, subdigital scales have a thorn. Scale surfaces are covered by honeycombs and short hair-like structures (spines). As subdigital scales with a thorn in the center and honeycomb microstructures were also found in the terrestrial tree chameleon Ch. namaquensis, one can assume that this geometry is a convergent adaptation to terrestrial locomotion. Despite the great number of

  19. Computer Aided Simulation Machining Programming In 5-Axis Nc Milling Of Impeller Leaf

    Science.gov (United States)

    Huran, Liu

    At present, cad/cam (computer-aided design and manufacture) have fine wider and wider application in mechanical industry. For the complex surfaces, the traditional machine tool can no longer satisfy the requirement of such complex task. Only by the help of cad/cam can fulfill the requirement. The machining of the vane surface of the impeller leaf has been considered as the hardest challenge. Because of their complex shape, the 5-axis cnc machine tool is needed for the machining of such parts. The material is hard to cut, the requirement for the surface finish and clearance is very high, so that the manufacture quality of impeller leaf represent the level of 5-axis machining. This paper opened a new field in machining the complicated surface, based on a relatively more rigid mathematical basis. The theory presented here is relatively more systematical. Since the lack of theoretical guidance, in the former research, people have to try in machining many times. Such case will be changed. The movement of the cutter determined by this method is definite, and the residual is the smallest while the times of travel is the fewest. The criterion is simple and the calculation is easy.

  20. Mechanical and thermal properties of date palm leaf fiber reinforced recycled poly (ethylene terephthalate) composites

    International Nuclear Information System (INIS)

    Dehghani, Alireza; Madadi Ardekani, Sara; Al-Maadeed, Mariam A.; Hassan, Azman; Wahit, Mat Uzir

    2013-01-01

    Highlights: • A novel natural fiber reinforced recycled poly (ethylene terephthalate) composite was prepared. • Mechanical performance and thermal behavior of the composites were investigated. • Composites with improved toughness and strength were achieved. - Abstract: Development of a recycled poly (ethylene terephthalate) (PETr) reinforced with surface treated date palm leaf fiber (DPLF) composites with enhanced mechanical properties have been studied. Surface modified date palm leaf fiber reinforced PETr composites were prepared using twin-screw extruder followed by injection molding and the influence of the DPLF content on the mechanical and thermal behavior of the PETr matrix was evaluated. Upon the addition of fibers, remarkable enhancements in the mechanical properties of the composites were observed. Scanning electron microscopy (SEM) images taken from DPLF fibers showed significant enhancements in the fiber’s surface topography after the surface treatment process. Dynamic mechanical analysis (DMA) indicated that the addition of DPLF to PETr matrix increased the composites toughness. The crystallization behavior of the samples, analyzed by differential scanning calorimetry (DSC) indicated an increase in the onset crystallization temperature and showed a higher degree of crystallinity of the composites as compared to PETr, demonstrating that DPLF particles could act as nucleating agents. The results point to the composite’s potential in wider indoor applications

  1. The Effect of Leaf Stacking on Leaf Reflectance and Vegetation Indices Measured by Contact Probe during the Season

    Czech Academy of Sciences Publication Activity Database

    Neuwirthová, E.; Lhotáková, Z.; Albrechtová, Jana

    2017-01-01

    Roč. 17, č. 6 (2017), s. 1-23, č. článku 1202. ISSN 1424-8220 Institutional support: RVO:67985939 Keywords : broadleaved trees * leaf optical properties * leaf traits Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 2.677, year: 2016

  2. 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

  3. Antioxidative Activity of Tobacco Leaf Protein Hydrolysates

    Directory of Open Access Journals (Sweden)

    Guohua Rao

    2007-01-01

    Full Text Available Discarded tobacco leaf protein hydrolysate (DTLPH was prepared by enzymatic hydrolysis using papain and then separated using ultrafiltration (UF membranes with molecular mass cut-off (MMCO of 10, 5, 3 and 1 kDa. Four permeate fractions including 10-K, 5-K, 3-K and 1-K (the permeate fractions from 10, 5, 3 and 1 kDa hydrolysate fractions were obtained. The 5-K hydrolysate fraction had high oxidation inhibilitory ratio (42.62 %, which was about twofold higher than the original hydrolysate and as high as that of vitamin E (α-tocopherol. The fractionated hydrolysates were superior to the original hydrolysate in the antioxidative activity tested. Moreover, these separated hydrolysates showed the enhanced functional property. The amino acid composition of 5-K hydrolysate was analyzed and the results show that the high antioxidative activity of 5-K hydrolysate was derived from high content of histidine, methionine, cystine and tryptophan.

  4. Immune defense in leaf-cutting ants

    DEFF Research Database (Denmark)

    Armitage, Sophie A O; Broch, Jens F; Marín, Hermogenes Fernández

    2011-01-01

    To ameliorate the impact of disease, social insects combine individual innate immune defenses with collective social defenses. This implies that there are different levels of selection acting on investment in immunity, each with their own trade-offs. We present the results of a cross......-fostering experiment designed to address the influences of genotype and social rearing environment upon individual and social immune defenses. We used a multiply mating leaf-cutting ant, enabling us to test for patriline effects within a colony, as well as cross-colony matriline effects. The worker's father influenced...... both individual innate immunity (constitutive antibacterial activity) and the size of the metapleural gland, which secretes antimicrobial compounds and functions in individual and social defense, indicating multiple mating could have important consequences for both defense types. However, the primarily...

  5. Peracylated Glucosyl Kaempferols from Pasania dodonfifolia Leaf.

    Science.gov (United States)

    Chang, Chi-Chih; Lee, Shoei-Sheng

    2015-08-01

    Phytochemical investigation of the ethanolic extract of Pasania dodoniifolia leaf led to the isolation of four kaempferol 3-0-peracylated glucosides (1-4), together with four flavonoid glucosides (5-8), epicatechin (9), and (7S, 7'S, 8R, 8'R)-icariol A2 (10). Of these, kaempferol-3-O-(3",4"-di-O-acetyl-2"-O-(Z)-p- coumaroyl)-6"-O-(E)-p-coumaroyl)-beta-glucopyranoside (3) and 3-O-(3",4"-di-O-acetyl-2",6"-di-O-(Z)-p-coumaroyl)-beta-glucopyranoside (4) are new and their structures were elucidated by 2D NMR spectroscopic analyses and MS data.

  6. Adsorption Studies of Radish Leaf Powder

    Directory of Open Access Journals (Sweden)

    Ankita

    2016-01-01

    Full Text Available Radish leaves (Raphanus sativus powder fractions was subjected to moisture adsorption isotherms at different isothermal temperature conditions from 15-45°C with an equal interval of 10°C. The sorption data obtained in gravimetric static method under 0.11–0.90 water activity conditions were subjected for sorption isotherms and found to be typical sigmoid trend. Experimental data were assessed for the applicability in the prediction through sorption models fitting and found that Polynomial and GAB equations performed well over all fitted models in describing equilibrium moisture content – equilibrium relative humidity (EMC–ERH relationships for shelf stable dehydrated radish leaf powder, over the entire range of temperatures condition under study. The net isosteric heat of sorption, differential entropy and free energy were determined at different temperatures and their dependence was seen with respect to equilibrium moisture content.

  7. Iridoids from leaf extract of Genipa americana

    Directory of Open Access Journals (Sweden)

    Jovelina S.F. Alves

    Full Text Available Abstract Genipa americana L., Rubiaceae, is a plant native from Brazil popularly known as “jenipapo”. Two iridoids, 1-hydroxy-7-(hydroxymethyl-1,4aH,5H,7aH-cyclopenta[c]pyran-4-carbaldehyde (1, and iridoid 7-(hydroxymethyl-1-methoxy-1H,4aH,5H,7aH-cyclopenta[c]pyran-4-carbaldehyde (2 were isolated and identified in the leaf extract of G. americana. Compounds 1 and 2 were identified for the first time in G. americana, and 1 has not been yet described in literature. These substances were analyzed by spectroscopic techniques such as infrared, high resolution mass spectrometry, 1H and 13C 1D; as well as 2D nuclear magnetic resonance. Moreover, the presence of flavonoids was detected by a preliminary analysis by Thin Layer Chromatography.

  8. Models for leaf area estimation in dwarf pigeon pea by leaf dimensions

    Directory of Open Access Journals (Sweden)

    Rafael Vieira Pezzini

    2018-03-01

    Full Text Available ABSTRACT This study aims to determine the most suitable model to estimate the leaf area of dwarf pigeon pea in function of the leaf central leaflet dimension. Six samplings of 200 leaves were performed in the first experiment, at 36, 42, 50, 56, 64, and 72 days after emergence (DAE. In the second experiment, seven samplings of 200 leaves were performed at 29, 36, 43, 49, 57, 65, and 70 DAE, totaling 2600 leaves. The length (L and width (W of the central leaflet were measured in all leaves composed by left, central, and right leaflets, the product of length times width (LW was calculated, and the leaf area (Y – sum of left, central, and right leaflet areas was determined by digital images. Linear, power, quadratic, and cubic models of Y as function of L, W, and LW were built using data from the second experiment. Leaves from the first experiment were used to validate the models. In dwarf pigeon pea, the linear (Ŷ = – 0.4088 + 1.6669x, R2 = 0.9790 is preferable, but power (Ŷ = 1.6097x1.0065, R2 = 0.9766, quadratic (Ŷ = – 0.3625 + 1.663x + 0.00007x2, R2 = 0.9790, and cubic (Ŷ = 0.7216 + 1.522x + 0.005x2 – 5E–05x3, R2 = 0.9791 models in function of LW are also suitable to estimate the leaf area obtained by digital images. The power model (Ŷ = 5.2508x1.7868, R2 = 0.95 based on the central leaflet width is less laborious because requires only one variable, but it presents accuracy reduction.

  9. Computer controlled multi-leaf conformation radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, T [Tokyo Metropolitan Komagome Hospital (Japan); Inamura, K

    1981-10-01

    A conformation radiotherapy system with 5-split collimators of which openings can be controlled symmetrically by computerized techniques during rotational irradiation by a linear accelerator has been developed. Outline of the system performance and its clinical applications are described as follows. 1. Profile of the system: The hardware is composed of three parts, namely, the multi-split collimator, the electronic data processor, and the interface between those two parts. 1) The multi-leaf collimator is composed of 5 pairs (10 leaves) diaphragms. It can be mounted to the X-ray head of a linear accelerator when used, and can be dismounted after its use. 2) The electronic data processor sends control signal to the collimator according to the 5-leaf target volume data which can be stored into a minifloppy disc through the curve digitizer previously. This part is composed of a) dedicated micro processor, b) I/O expansion unit, c) color CRT display with key board, d) dual mini-floppy disc unit, e) curve digitizer and f) digital plotter for recording and verification of resulted accuracy. 2. Performance of the system: 1) Maximum field size: 15 cm x 15 cm at isocenter. 2) Maximum elongation ratio of the target volume: 3 : 1 when the longer diameter is 15 cm. 3) Control accuracy: Within +-3 mm deviation from planned beam focus at isocenter. 3. Clinical application: The method of treatment planning and clinical advantages of this irradiation method are explained by raising clinical experiences such as treating brain tumor and rectal cancer.

  10. Computer controlled multi-leaf conformation radiotherapy

    International Nuclear Information System (INIS)

    Matsuda, Tadayoshi; Inamura, Kiyonari.

    1981-01-01

    A conformation radiotherapy system with 5-split collimators of which openings can be controlled symmetrically by computerized techniques during rotational irradiation by a linear accelerator has been developed. Outline of the system performance and its clinical applications are described as follows. 1. Profile of the system: The hardware is composed of three parts, namely, the multi-split collimator, the electronic data processor, and the interface between those two parts. 1) The multi-leaf collimator is composed of 5 pairs (10 leaves) diaphragms. It can be mounted to the X-ray head of a linear accelerator when used, and can be dismounted after its use. 2) The electronic data processor sends control signal to the collimator according to the 5-leaf target volume data which can be stored into a minifloppy disc through the curve digitizer previously. This part is composed of a) dedicated micro processor, b) I/O expansion unit, c) color CRT display with key board, d) dual mini-floppy disc unit, e) curve digitizer and f) digital plotter for recording and verification of resulted accuracy. 2. Performance of the system: 1) Maximum field size: 15 cm x 15 cm at isocenter. 2) Maximum elongation ratio of the target volume: 3 : 1 when the longer diameter is 15 cm. 3) Control accuracy: Within +-3 mm deviation from planned beam focus at isocenter. 3. Clinical application: The method of treatment planning and clinical advantages of this irradiation method are explained by raising clinical experiences such as treating brain tumor and rectal cancer. (author)

  11. Stem and leaf anatomy of Plectranthus neochilus Schltr., Lamiaceae

    Directory of Open Access Journals (Sweden)

    Márcia do Rocio Duarte

    Full Text Available Plectranthus neochilus Schltr. is an aromatic herb named " boldo" or " boldo-gambá" and employed for treating hepatic insufficiency and dyspepsia in folk medicine. This paper has investigated its stem and leaf anatomy, in order to contribute for the medicinal plant identification. The botanical material was prepared according to standard microtechniques. The stem has quadrangular transection and, in secondary growth at the level analyzed, shows uniseriate epidermis and numerous trichomes. The glandular ones are capitate and peltate. The former has short unicellular or long multicellular stalk and uni- or bicellular head. The latter presents short stalk and eight-celled ovoid head. The non-glandular trichomes are multicellular, uniseriate and coated with granular cuticle. It is observed angular collenchyma, cambia forming phloem outward and xylem inward, and perivascular fiber caps next to the phloem. The blade has uniseriate epidermis coated with striate cuticle, diacytic stomata on both surfaces, numerous trichomes similar to the stem ones, and homogeneous mesophyll. The midrib shows one or two collateral bundles and the petiole has many of them distributed as an open arc.

  12. Interaction between Vaccinium bracteatum Thunb. leaf pigment and rice proteins.

    Science.gov (United States)

    Wang, Li; Xu, Yuan; Zhou, Sumei; Qian, Haifeng; Zhang, Hui; Qi, Xiguang; Fan, Meihua

    2016-03-01

    In this study, we investigated the interaction of Vaccinium bracteatum Thunb. leaf (VBTL) pigment and rice proteins. In the presence of rice protein, VBTL pigment antioxidant activity and free polyphenol content decreased by 67.19% and 68.11%, respectively, and L(∗) of the protein-pigment complex decreased significantly over time. L(∗) values of albumin, globulin and glutelin during 60-min pigment exposure decreased by 55.00, 57.14, and 54.30%, respectively, indicating that these proteins had bound to the pigment. A significant difference in protein surface hydrophobicity was observed between rice proteins and pigment-protein complexes, indicating that hydrophobic interaction is a major binding mechanism between VBTL pigment and rice proteins. A significant difference in secondary structures between proteins and protein-pigment complexes was also uncovered, indicating that hydrogen bonding may be another mode of interaction between VBTL pigment and rice proteins. Our results indicate that VBTL pigment can stain rice proteins with hydrophobic and hydrogen interactions. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    Scurlock, J. M. O.; Asner, G. P.; Gower, S. T.

    2001-01-01

    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 originalsource references.This report documents the development of this data set, its contents, and its availability on the Internet from the Oak Ridge National Laboratory Distributed Active Archive Center for Biogeochemical Dynamics. Caution is advised in using these data, which were collected using a wide range of methodologies and assumptions that may not allow comparisons among sites.

  14. Photoreduction of chlorothalonil fungicide on plant leaf models.

    Science.gov (United States)

    Monadjemi, S; El Roz, M; Richard, C; Ter Halle, A

    2011-11-15

    Photodegradation is seldom considered at the surface of vegetation after crop spraying. Chlorothalonil, a broad-spectrum foliar fungicide with a very widespread use worldwide, was considered. To represent the waxy upper layer of leaves, tests were performed within thin paraffin wax films or in n-heptane. Laser flash photolysis together with steady-state irradiation in n-heptane allowed the determination of the photodegradation mechanisms Chlorothalonil ability to produce singlet oxygen was measured; noteworthy its efficiency is close to 100%. Additionally, chlorothalonil photodegradation mainly proceeds through reductive dechlorination. In these hydrophobic media, a radical mechanism was evidenced. Photochemical tests on wax films under simulated solar light show that formulated chlorothalonil is more reactive than pure chlorothalonil. The field-extrapolated half-life of photolysis on vegetation was estimated to 5.3 days. This value was compared to the half-lives of penetration and volatilization available in the literature. It appears that chlorothalonil dissipation from crops is ruled by both photodegradation and penetration. The relative importance of the two paths probably depends on meteorological factors and on physicochemical characteristics of the crop leaf cuticle.

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

    Science.gov (United States)

    Samavati, Vahid; Lorestani, Mohammad; Joolazadeh, Sajjad

    2014-04-01

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

  16. [Modeling polarimetric BRDF of leaves surfaces].

    Science.gov (United States)

    Xie, Dong-Hui; Wang, Pei-Juan; Zhu, Qi-Jiang; Zhou, Hong-Min

    2010-12-01

    The purpose of the present paper is to model a physical polarimetric bidirectional reflectance distribution function (pBRDF), which can character not only the non-Lambertian but also the polarized features in order that the pBRDF can be applied to analyze the relationship between the degree of polarization and the physiological and biochemical parameters of leaves quantitatively later. Firstly, the bidirectional polarized reflectance distributions from several leaves surfaces were measured by the polarized goniometer developed by Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences. The samples of leaves include two pieces of zea mays L. leaves (young leaf and mature leaf) and a piece of E. palcherrima wild leaf. Non-Lambertian characteristics of directional reflectance from the surfaces of these three leaves are obvious. A Cook-Torrance model was modified by coupling the polarized Fresnel equations to simulate the bidirectional polarized reflectance properties of leaves surfaces. The three parameters in the modified pBRDF model, such as diffuse reflectivity, refractive index and roughness of leaf surface were inversed with genetic algorithm (GA). It was found that the pBRDF model can fit with the measured data well. In addition, these parameters in the model are related with both the physiological and biochemical properties and the polarized characteristics of leaves, therefore it is possible to build the relationships between them later.

  17. MORPHOLOGICAL ANALYSIS OF THE LEAVES OF Anacardium occidentale L.

    Directory of Open Access Journals (Sweden)

    Glenda Quaresma Ramos

    2016-03-01

    Full Text Available In morphological studies are analyzed various parameters, ranging from macro scale through the micro scale to the nanometer scale, which contribute to the study of taxonomy, pharmacognosy, ecology, among others. Among the structures found in plants, the leaves are most organs analyzed. This study aimed to analyze morphological features of the leaves of the cashew tree, which is a plant of great commercial importance in Brazil. In this work we observed sinuous epidermal cells in the adaxial and abaxial, characterize their stomata in paracytic surrounded subsidiaries cells. On the abaxial surface the presence of glandular trichomes was observed; and cross-sectional analysis showed a single-layered epidermis with compact mesophyll and several layers of parenchyma cells. Keywords: leaf anatomy; cashew tree; optical microscopy.

  18. Inter and intra-specific variation in photosynthetic acclimation response to long term exposure of elevated carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Wilkinson, M. [Univ. of Essex, Colchester (United Kingdom)]|[Writtle Coll. (United Kingdom)

    1996-08-01

    The response of intra and interspecific variation in photosynthetic acclimation to growth at elevated atmospheric CO{sub 2} concentration (600{micro}mol mol-l) in six important grassland species was investigated. Plants were grown in a background sward of Lolium perenne and measurements were made after four years of growth at elevated C{sub a}. Elevated CO{sub 2} was maintained using a FACE (Free-Air Carbon Enrichment) system. Significant intra and interspecific variation in acclimation response was demonstrated. The response of adaxial and abaxial stomatal conductance to elevated CO{sub 2} was also investigated. The stomatal conductance of both the adaxial and abaxial leaf surfaces was found to be reduced by elevated C{sub a}. Significant asymmetric responses in stomatal conductance was demonstrated in D. glomerata and T. pratense. Analysis of stomatal indices and densities indicated that the observed reductions in stomatal conductance were probably the result of changes in stomatal aperture.

  19. Differential growth of pavement cells of Arabidopsis thaliana leaf epidermis as revealed by microbead labeling.

    Science.gov (United States)

    Elsner, Joanna; Lipowczan, Marcin; Kwiatkowska, Dorota

    2018-02-01

    In numerous vascular plants, pavement cells of the leaf epidermis are shaped like a jigsaw-puzzle piece. Knowledge about the subcellular pattern of growth that accompanies morphogenesis of such a complex shape is crucial for studies of the role of the cytoskeleton, cell wall and phytohormones in plant cell development. Because the detailed growth pattern of the anticlinal and periclinal cell walls remains unknown, our aim was to measure pavement cell growth at a subcellular resolution. Using fluorescent microbeads applied to the surface of the adaxial leaf epidermis of Arabidopsis thaliana as landmarks for growth computation, we directly assessed the growth rates for the outer periclinal and anticlinal cell walls at a subcellular scale. We observed complementary tendencies in the growth pattern of the outer periclinal and anticlinal cell walls. Central portions of periclinal walls were characterized by relatively slow growth, while growth of the other wall portions was heterogeneous. Local growth of the periclinal walls accompanying lobe development after initiation was relatively fast and anisotropic, with maximal extension usually in the direction along the lobe axis. This growth pattern of the periclinal walls was complemented by the extension of the anticlinal walls, which was faster on the lobe sides than at the tips. Growth of the anticlinal and outer periclinal walls of leaf pavement cells is heterogeneous. The growth of the lobes resembles cell elongation via diffuse growth rather than tip growth. © 2018 Botanical Society of America.

  20. Green synthesis of silver nanoparticles from Moringa oleifera leaf extracts and its antimicrobial potential

    Science.gov (United States)

    Moodley, Jerushka S.; Babu Naidu Krishna, Suresh; Pillay, Karen; Sershen; Govender, Patrick

    2018-03-01

    In this study we report on the synthesis of silver nanoparticles (AgNPs) from the leaf extracts of Moringa oleifera using sunlight irradiation as primary source of energy, and its antimicrobial potential. Silver nanoparticle formation was confirmed by surface plasmon resonance at 450 nm and 440 nm, respectively for both fresh and freeze-dried leaf samples. Crystanality of AgNPs was confirmed by transmission electron microscopy, scanning electron microscopy with energy dispersive x-ray spectroscopy and Fourier transform infrared (FTIR) spectroscopy analysis. FTIR spectroscopic analysis suggested that flavones, terpenoids and polysaccharides predominate and are primarily responsible for the reduction and subsequent capping of AgNPs. X-ray diffraction analysis also demonstrated that the size range of AgNPs from both samples exhibited average diameters of 9 and 11 nm, respectively. Silver nanoparticles showed antimicrobial activity on both bacterial and fungal strains. The biosynthesised nanoparticle preparations from M. oleifera leaf extracts exhibit potential for application as broad-spectrum antimicrobial agents.

  1. Convergence in the temperature response of leaf respiration across biomes and plant functional types.

    Science.gov (United States)

    Heskel, Mary A; O'Sullivan, Odhran S; Reich, Peter B; Tjoelker, Mark G; Weerasinghe, Lasantha K; Penillard, Aurore; Egerton, John J G; Creek, Danielle; Bloomfield, Keith J; Xiang, Jen; Sinca, Felipe; Stangl, Zsofia R; Martinez-de la Torre, Alberto; Griffin, Kevin L; Huntingford, Chris; Hurry, Vaughan; Meir, Patrick; Turnbull, Matthew H; Atkin, Owen K

    2016-04-05

    Plant respiration constitutes a massive carbon flux to the atmosphere, and a major control on the evolution of the global carbon cycle. It therefore has the potential to modulate levels of climate change due to the human burning of fossil fuels. Neither current physiological nor terrestrial biosphere models adequately describe its short-term temperature response, and even minor differences in the shape of the response curve can significantly impact estimates of ecosystem carbon release and/or storage. Given this, it is critical to establish whether there are predictable patterns in the shape of the respiration-temperature response curve, and thus in the intrinsic temperature sensitivity of respiration across the globe. Analyzing measurements in a comprehensive database for 231 species spanning 7 biomes, we demonstrate that temperature-dependent increases in leaf respiration do not follow a commonly used exponential function. Instead, we find a decelerating function as leaves warm, reflecting a declining sensitivity to higher temperatures that is remarkably uniform across all biomes and plant functional types. Such convergence in the temperature sensitivity of leaf respiration suggests that there are universally applicable controls on the temperature response of plant energy metabolism, such that a single new function can predict the temperature dependence of leaf respiration for global vegetation. This simple function enables straightforward description of plant respiration in the land-surface components of coupled earth system models. Our cross-biome analyses shows significant implications for such fluxes in cold climates, generally projecting lower values compared with previous estimates.

  2. Organic compounds leached from fast pyrolysis mallee leaf and bark biochars.

    Science.gov (United States)

    Lievens, Caroline; Mourant, Daniel; Gunawan, Richard; Hu, Xun; Wang, Yi

    2015-11-01

    Characterization of organic compounds leached from biochars is essential in assessing the possible toxicity of the biochar to the soils' biota. In this study the nature of the leached organic compounds from Mallee biochars, produced from pyrolysis of Mallee leaf and bark in a fluidised-bed pyrolyser at 400 and 580°C was investigated. Light bio-oil compounds and aromatic organic compounds were investigated. The 'bio-oil like' light compounds from leaf and bark biochars 'surfaces were obtained after leaching the chars with a solvent, suitable to dissolve the respective bio-oils. GC/MS was implemented to investigate the leachates. Phenolics, which are potentially harmful toxins, were detected and their concentration shown to be dependent on the char's origin and the char production temperature. Further, to simulate biochars amendment to soils, the chars were leached with water. The water-leached aromatic compounds from leaf and bark biochars were characterized using UV-fluorescence spectroscopy. Those results suggested that biochars contain leachable compounds of which the nature and amount is dependent on the biomass feedstock, pyrolysis temperature and leaching time. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Rapid hydraulic recovery in Eucalyptus pauciflora after drought: linkages between stem hydraulics and leaf gas exchange.

    Science.gov (United States)

    Martorell, Sebastià; Diaz-Espejo, Antonio; Medrano, Hipólito; Ball, Marilyn C; Choat, Brendan

    2014-03-01

    In woody plants, photosynthetic capacity is closely linked to rates at which the plant hydraulic system can supply water to the leaf surface. Drought-induced embolism can cause sharp declines in xylem hydraulic conductivity that coincide with stomatal closure and reduced photosynthesis. Recovery of photosynthetic capacity after drought is dependent on restored xylem function, although few data exist to elucidate this coordination. We examined the dynamics of leaf gas exchange and xylem function in Eucalyptus pauciflora seedlings exposed to a cycle of severe water stress and recovery after re-watering. Stomatal closure and leaf turgor loss occurred at water potentials that delayed the extensive spread of embolism through the stem xylem. Stem hydraulic conductance recovered to control levels within 6 h after re-watering despite a severe drought treatment, suggesting an active mechanism embolism repair. However, stomatal conductance did not recover after 10 d of re-watering, effecting tighter control of transpiration post drought. The dynamics of recovery suggest that a combination of hydraulic and non-hydraulic factors influenced stomatal behaviour post drought. © 2013 John Wiley & Sons Ltd.

  4. Green Synthesis of Silver Nanoparticles by using Eucalyptus Globulus Leaf Extract

    Science.gov (United States)

    Balamurugan, Madheswaran; Saravanan, Shanmugam

    2017-12-01

    A single step eco-friendly, energy efficient and economically scalable green method was employed to synthesize silver nanoparticles. In this work, the synthesis of silver nanoparticles using Eucalyptus globulus leaf extract as reducing and capping agent along with water as solvent at normal room temperature is described. Silver nanoparticles were prepared from aqueous silver nitrate solution by adding the leaf extract. The prepared nanoparticles were characterized by using UV-visible Spectrophotometer, X-ray diffractometer, High Resolution Transmission Electron Microscope (HR-TEM) and Fourier Transform Infrared Spectroscope (FTIS). X-ray diffraction studies brought to light the crystalline nature and the face centered cubic structure of the silver nanoparticles. Using HR-TEM. the nano sizes and morphology of the particles were studied. The mean sizes of the prepared silver nanoparticles ranged from 30 to 36 nm. The density of the particles was tuned by varying the molar ratio of silver nitrate. FTIS studies showed the functional group of organic molecules which were located on the surface of the silver nanoparticles. Originating from the leaf extracts, these organic molecules reduced and capped the particles.

  5. Simulation and Failure Analysis of Car Bumper Made of Pineapple Leaf Fiber Reinforced Composite

    Science.gov (United States)

    Arbintarso, E. S.; Muslim, M.; Rusianto, T.

    2018-02-01

    The bumper car made of the Pineapple Leaf Fiber Reinforced Composite (PLFRC) is possible to be produced with the advantage of easy to get, and cheap. Pineapple leaf fiber has chosen as a natural fiber, which the maximum of the strength of 368 MPa. The objective of this study was to determine the maximum capability of front car bumpers using Pineapple Leaf Fiber Reinforced Composite materials through the process of simulating stress analysis with Solidworks 2014 software. The aim also to know the distribution of loads that occur on the front car bumper and predict the critical point position on the design of the bumper. The result will use to develop the alternative lightweight, cheap and environmentally friendly materials in general and the development of the use of pineapple fiber for automotive purposes in particular. Simulations and failure analysis have been conducted and showed an increased impact speed in line with increased displacement, strain, and stress that occur on the surface of the bumper. The bumper can withstand collisions at a speed of less than 70 kph.

  6. Seasonal and local differences in leaf litter flammability of six Mediterranean tree species.

    Science.gov (United States)

    Kauf, Zorica; Fangmeier, Andreas; Rosavec, Roman; Španjol, Željko

    2015-03-01

    One of the suggested management options for reducing fire danger is the selection of less flammable plant species. Nevertheless, vegetation flammability is both complex and dynamic, making identification of such species challenging. While large efforts have been made to connect plant traits to fire behavior, seasonal changes and within species variability of traits are often neglected. Currently, even the most sophisticated fire danger systems presume that intrinsic characteristics of leaf litter stay unchanged, and plant species flammability lists are often transferred from one area to another. In order to assess if these practices can be improved, we performed a study examining the relationship between morphological characteristics and flammability parameters of leaf litter, thereby taking into account seasonal and local variability. Litter from six Mediterranean tree species was sampled throughout the fire season from three different locations along a climate gradient. Samples were subjected to flammability testing involving an epiradiator operated at 400 °C surface temperature with 3 g sample weight. Specific leaf area, fuel moisture content, average area, and average mass of a single particle had significant influences on flammability parameters. Effects of sampling time and location were significant as well. Due to the standardized testing conditions, these effects could be attributed to changes in intrinsic characteristics of the material. As the aforementioned effects were inconsistent and species specific, these results may potentially limit the generalization of species flammability rankings. Further research is necessary in order to evaluate the importance of our findings for fire danger modeling.

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

    Science.gov (United States)

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

    2017-10-11

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

  8. Green synthesis and antimicrobial activity of monodisperse silver nanoparticles synthesized using Ginkgo Biloba leaf extract

    Science.gov (United States)

    Ren, Yan-yu; Yang, Hui; Wang, Tao; Wang, Chuang

    2016-11-01

    Various parts of plants can be used as a raw material for the synthesis of nanoparticles, which is eco-friendly way and does not involve any harmful chemicals. In this project, Ginkgo biloba leaf, an abundantly available medicinal plant in China, was for the first time adopted as a reducing and stabilizing agent to synthesize smaller sized and stable silver nanoparticles (AgNPs). To improve the quality of AgNPs, the reduction was accelerated by changing the concentrations of initial Ag+ (0.02, 0.04, 0.06 and 0.08 mol/L) of the reaction mixture consisting of silver nitrate solution (AgNO3) and Ginkgo biloba leaf extract. At pH = 8 and lower AgNO3 concentration (0.02 mol/L), a colloid consisting of well-dispersed spherical nanoparticles was obtained. The synthesized nanocrystals were successfully characterized by UV-vis and XRD. TEM images revealed the size of the spherical AgNPs ranged between 10-16 nm. FTIR analysis revealed that biological macromolecules with groups of sbnd NH2, sbnd OH, and others were distributed on the surface of the nanoparticles. The biosynthesized AgNPs exhibited good antibacterial activities against gram-negative bacteria and gram-positive bacteria. Compared to traditional chemical methods, Ginkgo biloba leaf extract provides an easy green synthetical way. It is anticipated that the biosynthesized AgNPs can be used in areas such as cosmetics, foods and medical applications.

  9. Effects of microhabitat on leaf traits in Digitalis grandiflora L. (Veronicaceae growing at forest edge and interior

    Directory of Open Access Journals (Sweden)

    Kołodziejek J.

    2014-01-01

    Full Text Available The morphological, anatomical and biochemical traits of the leaves of yellow foxglove (Digitalis grandiflora Mill. from two microhabitats, forest interior (full shade under oak canopy and forest edge (half shade near shrubs, were studied. The microhabitats differed in the mean levels of available light, but did not differ in soil moisture. The mean level of light in the forest edge microhabitat was significantly higher than in the forest interior. Multivariate ANOVA was used to test the effects of microhabitat. Comparison of the available light with soil moisture revealed that both factors significantly influenced the morphological and anatomical variables of D. grandiflora. Leaf area, mass, leaf mass per area (LMA, surface area per unit dry mass (SLA, density and thickness varied greatly between leaves exposed to different light regimes. Leaves that developed in the shade were larger and thinner and had a greater SLA than those that developed in the half shade. In contrast, at higher light irradiances, at the forest edge, leaves tended to be thicker, with higher LMA and density. Stomatal density was higher in the half-shade leaves than in the full-shade ones. LMA was correlated with leaf area and mass and to a lesser extent with thickness and density in the forest edge microsite. The considerable variations in leaf density and thickness recorded here confirm the very high variation in cell size and amounts of structural tissue within species. The leaf plasticity index (PI was the highest for the morphological leaf traits as compared to the anatomical and biochemical ones. The nitrogen content was higher in the “half-shade leaves” than in the “shade leaves”. Denser leaves corresponded to lower nitrogen (N contents. The leaves of plants from the forest edge had more potassium (K than leaves of plants from the forest interior on an area basis but not on a dry mass basis; the reverse was true for phosphorus.

  10. Surface Water & Surface Drainage

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This data set contains boundaries for all surface water and surface drainage for the state of New Mexico. It is in a vector digital data structure digitized from a...

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

    Science.gov (United States)

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

    2013-05-06

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

  12. Importance of Secondary Metabolites for Leaf Beetles (Coleoptera: Chrysomelidae

    Directory of Open Access Journals (Sweden)

    A. N. EKİZ

    2014-06-01

    Full Text Available Leaf beetles (Chrysomelidae are one of the most diverse families of herbivorous insects. Many of them are important agricultural pests and cause remarkable loss of crop and money as well. Plant leaves and roots are primary food source of both larva and adults of leaf beetles. Plants produce many secondary metabolites in reaction to herbivore insects. It is a well-known phenomenon that quantity and variety of secondary metabolites in plant leaves may change in response to insect attacks. Herbivore insects have to deal with such defensive secondary chemicals and overcome either by detoxifying or storing them. Accordingly, many specialist herbivores coevolved with their host plant. Certain phenolic glycosides may reduce leaf beetle feeding. Condensed tannins are anti-herbivore defenses against leaf chewing beetles, including leaf beetles. Flavonoid compounds are feeding deterrents for many flea leaf beetles. Cinnamic acid derivatives are other known feeding deterrents for leaf beetles. Secondary metabolites quantity and nutritional quality of host plants are not only important for feeding but also for providing enemy-free space and suitable oviposition sites.

  13. Leaf temperature and stomatal influences on sap velocity diurnal hysteresis in the Amazon rainforest

    Science.gov (United States)

    Jardine, K.; Gimenez, B.; Negron Juarez, R. I.; Koven, C.; Powell, T.; Higuchi, N.; Chambers, J.; Varadharajan, C.

    2016-12-01

    In order to improve our ability to predict terrestrial evapotranspiration fluxes, an understanding of the interactions between plant physiology and environmental conditions is necessary, but remains poorly characterized, especially in tropical ecosystems. In this study we show a tight positive correlation between sap velocity (at 1 m of height) and leaf surface temperature (LST, 20-30 m of height) in canopy dominant trees in two primary rainforest sites in the Amazon basin (Santarém and Manaus, Brazil). As leaf temperatures varied throughout the day, sap velocity responded with little delay (<15 min). Positive sap velocity was often observed at night, but also closely followed night time LSTs. When plotted versus LST, sap velocity showed an exponential increase before reaching a reflection point and a plateau and is characterized as a sigmoidal curve, in all observed trees. Moreover, a clear diurnal hysteresis in sap velocity was evident with morning periods showing higher temperature sensitivities than afternoon and night periods. Diurnal leaf observations showed a morning peak in stomatal conductance ( 10:00-10:30), but a mid-day to afternoon peak in transpiration and leaf temperature (12:00-14:00). Our observations suggest the sap velocity-LST hysteresis pattern arises due to the temporal offset between stomatal conductance and vapor pressure deficits (VPD) and demonstrates the dominating effect of VPD over stomatal conductance in maintaining high transpiration/sap flow rates under elevated temperatures. Our results have important implications for modeling tropical forest transpiration and suggests the possibility of predicting evapotranspiration fluxes at the ecosystem to regional scales based on remote sensed vegetation temperature.

  14. Green synthesis and antimicrobial activity of monodisperse silver nanoparticles synthesized using Ginkgo Biloba leaf extract

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Yan-yu [School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xi' an 710021 (China); Yang, Hui, E-mail: 549456369@qq.com [School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xi' an 710021 (China); Wang, Tao [School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xi' an 710021 (China); Wang, Chuang