Journal articles on the topic 'Remaining leaf area'
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1
Liu, Guofan, and Kent D. Kobayashi. "250 Using Leaf Area Devices (LADS) to Estimate Total Leaf Area of Coffee Plants." HortScience 34, no. 3 (June 1999): 485C—485. http://dx.doi.org/10.21273/hortsci.34.3.485c.
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It is difficult to estimate the total leaf area of coffee plants with accuracy due to the large number of leaves and the high leaf density of the plant canopy. In 1996, on Maui, Hawaii, 98 leaves of various sizes were randomly collected for each of five cultivars of Coffea arabica L. The cultivars used were `Guadalupe', `Guatemalan', `Mokka', `Red Catuai', and `Yellow Caturra'. Leaf length, width, and area were measured. Seventy-five leaves were used to develop leaf area models, and the remaining leaves were used to test the accuracy of the models using a 1:1 line. We then developed leaf area devices (LADs), which were made of sheet plastic and shaped to resemble coffee leaves. There were three groups of areas in the leaf area devices, based on leaf sizes. Total leaf area (TLA) contained three components. Each component related to the mean leaf area (k) and the number of leaves (n) in that group. The model for the total leaf area was: TLA = k1n1 + k2n2 + k3n3, where k is a constant in each group. The estimation errors for the different cultivars ranged from 5.6% to 12.3% for 1-year-old plants (four cultivars) and from 1.9% to 7.8% for mature plants (five cultivars). By using the LADs and counting the number of leaves, we can obtain the total leaf area for coffee plants in the field.
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Bueno, Adeney de Freitas, Benjamin Zechmann, William Wyatt Hoback, Regiane Cristina Oliveira de Freitas Bueno, and Odair Aparecido Fernandes. "Serpentine leafminer (Liriomyza trifolii) on potato (Solanum tuberosum): field observations and plant photosynthetic responses to injury." Ciência Rural 37, no. 6 (December 2007): 1510–17. http://dx.doi.org/10.1590/s0103-84782007000600001.
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Serpentine leafminers, Liriomyza spp. (Diptera: Agromyzidae), are polyphagous insects that feed on numerous crops worldwide including potato. Recently, leafminer larvae (Liriomyza trifolii) have become an economically important pest of potato. The larvae eat the mesophyll of leaflets leaving long winding tunnels inside the leaflets. The photosynthetic effects of larval tunneling on the remaining leaf tissue are unknown. In 2003, physiological responses of potato to leafminer, L. trifolii were evaluated in Kearney, Nebraska, USA. The leaflets were examined 7 and 14 days post infestation for leaf area injury, photosynthetic rates and fluorescence. Leafminers caused up to 13% leaf area loss due to leafminer injury with no effect on the photosynthetic rates of the remaining leaf tissue thus having similar effects as other gross tissue removers. However, fluorescence measures revealed changes in the photosynthetic efficiency and depend of the type of injury, it may lead to early leaf senescence. Field monitoring of L. trifolii infestations showed that treatments with abamectin were effective in reducing leafminer numbers and had no immediate effect on beneficial parasitoid from Eulophidae family suggesting that abamectin is a good option for chemical control.
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Ribeiro, Ana Maria Alves de Souza, Daniel Alves Mundim, Daisy Cristina Martins Mendonça, Karina Tiemi Hassuda dos Santos, Jéssica Sayuri Hassuda Santos, Vinicius de Souza Oliveira, Gleyce Pereira Santos, et al. "Leaf Area Estimation of Garden Boldo From Linear Dimensions." Journal of Agricultural Science 11, no. 5 (April 15, 2019): 461. http://dx.doi.org/10.5539/jas.v11n5p461.
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The objective of this work was to determine a mathematical equation using linear measures that allows estimating a leaf area of the specie Plectranthus barbatus Andrews, a plant with medicinal properties popularly known as garden boldo. For this was performed a direct measurement of the leaf blade considering the length (L) along the midrib and the maximum width (W) perpendicular to the midrib of 500 leaves of different specimens and the observed foliar area (OLA), which were obtained by digitized images. A regression study with linear, quadratic, potential and exponential models was performed using a random sample of 400 from the evaluated leaves using OLA as a function of L, W or LW and then obtaining the estimated leaf area (ELA) of each model. From the remaining 100 leaves a validation of the tested models was performed using ELA as a function of OLA in a simple linear regression. From the residues between ELA and OLA the root-square-mean error and Willmot index (d) was obtained and the normality was verified. The parameters used for validation were: statistically linear and angular coefficient equal to zero and one respectively; coefficient of determination closest to the unit; RQME closer to zero; d index closest to the unit; normal distribution of residues. The equation that best represents the estimated leaf area of the garden boldo is ELA = 0.1389 + 0.6779 (LW).
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Simon, J. C., M. L. Decau, J. C. Avice, A. Jacquet, F. Meuriot, and J. M. Allirand. "Effects of initial N reserve status and residual leaf area after cutting on leaf area and organ establishment during regrowth of alfalfa." Canadian Journal of Plant Science 84, no. 4 (October 1, 2004): 1059–66. http://dx.doi.org/10.4141/p03-118.
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Nitrogen reserves in remaining organs and residual leaf area after cutting have long been recognized as key factors during alfalfa (Medicago sativa L.) regrowth. The present work examined which morphological components were influenced by contrasting initial N status and residual leaf area during 29 d of regrowth after cutting at 15 cm height. Two levels of initial N reserves (high and low) and of residual leaf areas (not or completely defoliated) were combined in four treatments. Both factors affected shoot dry matter (DM) production at the end of regrowth. The increase in DM of new organs observed with high N reserves resulted from a combination of short- and long-term effects on plant morphology; i.e., (1) an increase in the rate of axis appearance from the crown in the early regrowth stage (day 0–9) and (2) an increase in individual leaf area (ILA) all along the regrowth. Compared with completely defoliated plants, plants with a residual leaf area at cutting exhibited an increased rate of axillary stems appearance all along the regrowth. Then the architecture of plants with a residual leaf area was more branched than the one of defoliated plants. This increase in branching was always associated with smaller ILA. Hence, differences in plant leaf area were only significant in the early growth stage. This suggested that differences observed in new stems DM at the end of the regrowth were established by day 9 and remained unchanged in late regrowth. Our results clearly showed that initial N reserve status and residual leaf area both significantly modify the dynamic of leaf area establishment and new organ growth of alfalfa. Key words: Medicago sativa L., defoliation, morphology, N storage, stems regrowth
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Rubinstein, Adriana, and Heraldo L. Vasconcelos. "Leaf-litter decomposition in Amazonian forest fragments." Journal of Tropical Ecology 21, no. 6 (October 19, 2005): 699–702. http://dx.doi.org/10.1017/s0266467405002762.
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Most of the forests of the Amazon basin grow on nutrient-poor soils (Jordan 1982). Despite this, these forests remain productive through a variety of nutrient conservation mechanisms and a very effective system of organic matter decomposition and nutrient cycling (Jordan 1982). When an area of forest is fragmented however, the remaining patches experience modified microclimatic conditions (Camargo & Kapos 1995, Didham & Lawton 1999), and changes in floristic composition (Laurance et al. 1998), which can affect the decomposer community (Didham et al. 1996, Souza & Brown 1994) and consequently the decomposition process.
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Barclay, Hugh J., and Doug Goodman. "Conversion of total to projected leaf area index in conifers." Canadian Journal of Botany 78, no. 4 (April 21, 2000): 447–54. http://dx.doi.org/10.1139/b00-020.
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Several definitions of leaf area index (LAI) presently exist in the literature but the relationships among them are not clear. To compare the results of various studies, there is a need to convert from one definition to another. Factors for converting among four definitions of LAI are presented for six conifer species: Abies grandis (Dougl. ex D. Don) Lindl., Thuja plicata Donn ex D. Don., Tsuga heterophylla (Raf.) Sarg., Picea sitchensis (Bong.) Carr.), Pinus contorta Dougl., and Pseudotsuga menziesii (Mirb) Franco). Among the four definitions of LAI, the two extremes involve (i) the total area of the leaf and (ii) the projected area of nonhorizontal leaves, as they occur on the tree. If leaves are randomly oriented in space, then the conversion factor between definitions i and ii should be 0.25. Four of the six species have conversion factors very close to this value, and three of these four are relatively shade-intolerant,. The remaining two species, A. grandis and Thuja plicata, have conversion factors of approximately 0.35, owing to the approximately horizontal orientation of their leaves. These two species are both relatively shade-tolerant, and the trend toward horizontal leaves might be an adaptation to assist in shade tolerance. A sensitivity analysis indicated that the foliage of most of the species maximized the amount of light gathered when the light was coming from almost straight overhead, as is the case with many shaded forest trees.Key words: leaf area index, conifers, leaf area index conversion.
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Huang, Weiwei, David Ratkowsky, Cang Hui, Ping Wang, Jialu Su, and Peijian Shi. "Leaf Fresh Weight Versus Dry Weight: Which is Better for Describing the Scaling Relationship between Leaf Biomass and Leaf Area for Broad-Leaved Plants?" Forests 10, no. 3 (March 13, 2019): 256. http://dx.doi.org/10.3390/f10030256.
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Leaf dry mass per unit area (LMA) is considered to represent the photosynthetic capacity, which actually implies a hypothesis that foliar water mass (leaf fresh weight minus leaf dry weight) is proportional to leaf dry weight during leaf growth. However, relevant studies demonstrated that foliar water mass disproportionately increases with increasing leaf dry weight. Although scaling relationships of leaf dry weight vs. leaf area for many plants were investigated, few studies compared the scaling relationship based on leaf dry weight with that based on leaf fresh weight. In this study, we used the data of three families (Lauraceae, Oleaceae, and Poaceae, subfamily Bambusoideae) with five broad-leaved species for each family to examine whether using different measures for leaf biomass (i.e., dry weight and fresh weight) can result in different fitted results for the scaling relationship between leaf biomass and area. Reduced major axis regression was used to fit the log-transformed data of leaf biomass and area, and the bootstrap percentile method was used to test the significance of the difference between the estimate of the scaling exponent of leaf dry weight vs. area and that of leaf fresh weight vs. area. We found that there were five species across three families (Phoebe sheareri (Hemsl.) Gamble, Forsythia viridissima Lindl., Osmanthus fragrans Lour., Chimonobambusa sichuanensis (T.P. Yi) T.H. Wen, and Hibanobambusa tranquillans f. shiroshima H. Okamura) whose estimates of the scaling exponent of leaf dry weight to area and that of leaf fresh weight to area were not significantly different, whereas, for the remaining ten species, both estimates were significantly different. For the species in the same family whose leaf shape is narrow (i.e., a low ratio of leaf width to length) the estimates of two scaling exponents are prone to having a significant difference. There is also an allometric relationship between leaf dry weight and fresh weight, which means that foliar water mass disproportionately increases with increased leaf dry weight. In addition, the goodness of fit for the scaling relationship of leaf fresh weight vs. area is better than that for leaf dry weight vs. area, which suggests that leaf fresh mass might be more able to reflect the physiological functions of leaves associated with photosynthesis and respiration than leaf dry mass. The above conclusions are based on 15 broad-leaved species, although we believe that those conclusions may be potentially extended to other plants with broad and flat leaves.
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Kwon, Kei-Jung, Uuriintuya Odsuren, Sang-Yong Kim, Jong-Cheol Yang, and Bong-Ju Park. "Comparison of the Particulate Matter Removal Capacity of 11 Herbaceous Landscape Plants." Journal of People, Plants, and Environment 24, no. 3 (June 30, 2021): 267–75. http://dx.doi.org/10.11628/ksppe.2021.24.3.267.
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Background and objective Particulate matter (PM) has a fatal effect on health. There have been many studies on the use of plants such as trees and shrubs as eco-friendly and sustainable biofilter for the removal of PM. In forming more green space, ground cover plants play an important role in multi-layered planting. This study was conducted to investigate the ability of plants to reduce PM, targeting Korean native ground cover plants with high availability in urban green spaces. Methods For 4 species of Asteraceae, 4 species of Liliaceae, and 3 species of Rosaceae, one species of plants at a time were placed in an acrylic chamber (800 × 800 × 1000 mm, L × W × H) modeling an indoor space. After the injection of PM, the amount of PM remaining in the chamber over time was investigated. Results For all three types of PM (PM10, PM2.5, PM1), significant difference occurred in the amount of PM remaining between plant species after 1 hour in the Liliaceae chamber, 3 hours in the Asteraceae chamber, and 5 hours in the Rosaceae chamber. With Liliaceae, the leaf area and the amount of PM remaining in the chamber showed a negative (−) correlation. With the Asteraceae and Rosaceae, there was a weak negative correlation between the leaf area and the amount of PM remaining in the chamber. Conclusion When using ground cover plants as a biofilter to remove PM, it is considered effective to select a species with a large total leaf area, especially for Liliaceae.
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Tang, Yi Lin, Ben Zhi Zhou, Xiao Gai Ge, Xiao Ming Wang, and Qian Li. "Leaf-Litter Decomposition Dynamic, Carbon Loss and Nutrient Return for Moso Bamboo Forest with Different Litter Mass Accumulation." Advanced Materials Research 726-731 (August 2013): 4222–25. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.4222.
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To provide an important basic knowledge for the biogeochemical cycle of bamboo forest ecosystem, particularly the cycling of global carbon, we studied decomposition dynamics of leaf-litter with different mass accumulation in moso bamboo forest. Our study area located in Miaoshanwu nature reserve, Fuyang, Zhejiang province. Based on the survey, we concluded that: (1) the sequence of remaining mass of leaf-litter with different mass accumulation after 240 days' decomposition from the most to the least was in the following order: 30g (58.53%) > 60g (51.92%) > 90g (48.48%), implying that leaf-litter with more mass accumulation decomposed faster in the unit area. (2)The more accumulated leaf-litter lead to more TOC loss in leaf-litter which will not helpful for TOC increase on surface soil carbon pools. This implying that the faster leaf-litter decomposed, the less TOC increased on surface soil carbon pools in 240 day s' observation. (3)The concentration of N, P, K and Ca showed the similar tendency with initially increasing but decreasing gradually in the following stage and then increasing again in the next stage. And concentration of Mg, Fe, Cu and Zn increased gradually in the period of 0-240 days.
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Lopes, Daniela B., and Richard D. Berger. "The Effects of Rust and Anthracnose on the Photosynthetic Competence of Diseased Bean Leaves." Phytopathology® 91, no. 2 (February 2001): 212–20. http://dx.doi.org/10.1094/phyto.2001.91.2.212.
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The effects of rust (caused by Uromyces appendiculatus) and anthracnose (caused by Colletotrichum lindemuthianum) and their interaction on the photosynthetic rates of healthy and diseased bean (Phaseolus vulgaris) leaves were determined by gas-exchange analysis, in plants with each disease, grown under controlled conditions. The equation Px/P0 = (1 - x)β was used to relate relative photosynthetic rate (Px/P0) to proportional disease severity (x), where β represents the ratio between virtual and visual lesion. The β values obtained for rust were near one, indicating that the effect of the pathogen on the remaining green leaf area was minimal. The high values of β obtained for anthracnose (8.46 and 12.18) indicated that the photosynthesis in the green area beyond the necrotic symptoms of anthracnose was severely impaired. The impact of anthracnose on bean leaf photosynthesis should be considered in assessments of the proportion of healthy tissue in diseased leaves. The accurate assessment of the healthy portion of the leaf could improve the use of concepts such as healthy leaf area duration and healthy leaf area absorption, which are valuable predictors of crop yield. The equation used to analyze the interaction between rust and anthracnose on the same leaf was Pz = P0 (1 - x)βx × (1 - y)βy, where Pz is the relative photosynthetic rate of any given leaf, P0 is the maximum relative photosynthetic rate, x is anthracnose severity, y is rust severity, βx is the β value for anthracnose in the presence of rust, and βy is the β value for rust in the presence of anthracnose. From the resulting response surface, no interaction of the two diseases was observed. Dark respiration rate increased on diseased leaves compared with control leaves. The remaining green leaf area of leaves with both diseases was not a good source to estimate net photosynthetic rate because the effect of anthracnose extended far beyond the visual lesions, whereas the effect of rust on photosynthesis was essentially limited to the pustule plus halo.
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Alvim, Karen Rodrigues de Toledo, Césio Humberto de Brito, Afonso Maria Brandão, Luiz Savelli Gomes, and Maria Teresa Gomes Lopes. "The effect of leaf area reduction on corn plants during the reproduction phase." Revista Ceres 58, no. 4 (August 2011): 413–18. http://dx.doi.org/10.1590/s0034-737x2011000400002.
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Reduction in leaf area in corn plants during reproduction changes physiological metabolism and consequently the accumulation of dry matter in grains. The aim of this work was to study changes in agronomic characteristics caused by defoliation in corn during the reproduction phase. The experiment was carried out in Uberlândia, Minas Gerais state, in the agricultural year 2007/2008. The experiment was arranged in a randomized block design, consisting of seven treatments: control without defoliation, removal of two apical leaves, removal of four apical leaves, removal of all leaves above spike, removal of four intermediate leaves, removal of all leaves below spike, and removal of all plant leaves, with five repetitions. The genotype used for the evaluations was hybrid NB 7376. Defoliation was carried out when plants were at the growth stage R2. The variables assessed were: yield, density of spikes and corncobs, root resistance and stem integrity. When all leaves above the spike were removed, grain yield was reduced by 20%. Corncob density, stem integrity and root resistance to uprooting were also affected. Spike density was only affected when all plant leaves were removed. The leaf area remaining physiologically active above the spike was found to be most efficient in terms of grain yield.
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Rosenzweig, V. E., and D. V. Goloenko. "Breeding strategies for soybean canopy structure optimization in dry regions." Oil Crops 186, no. 2 (June 30, 2021): 24–30. http://dx.doi.org/10.25230/2412-608x-2021-2-186-24-30.
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Water supply is one of the key factors limiting soybean yield. Coming from the monsoon climate region, soybean lacks effective means of leaf surface growth restriction and is prone to produce excessive leaf area that leads to undesirable transpiration increase. Reducing branching rate and, correspondingly, leaf number per plant is usually proposed to decrease leaf area. However, as far as branching ability is generally a useful trait contributing to yield stability, we have undertaken a search for possible alternative ways of leaf area reduction. Soybean canopy structure was studied in our germplasm nursery in Kursk region. We have updated an express method of soybean trifoliate leaf surface calculation. A regression index for soybean trifoliate leaf surface by central leaflet length and width product characterizes leaflet shape and depends from its length to width ratio. In the sampling studied, trifoliate leaf surface varied from 79 to 150sq. cm. Leaf area index (LAI) varied from 4.0 to 8.6 sq. m/sq. m, with optimal LAI equal to 6.0 sq. m/sq. m. Excessive LAI (over 7.7 sq. m/sq. m) decreased yield by 20 %. Optimal LAI may be achieved by various combinations of leaf size and leaf number per plant. Lines possessing good branching rate but remaining within optimal LAI values due to small leaf size were revealed. Thus, lamina size reduction may be proposed as an alternative breeding direction to solve a conflict of bushy plant type and drought tolerance.
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Marler, Thomas E., and Anders J. Lindström. "Leaf Nutrient Relations of Cycads in a Common Garden." Tropical Conservation Science 14 (January 2021): 194008292110365. http://dx.doi.org/10.1177/19400829211036570.
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Background and Aims Research required to clarify leaf nutrient relations of cycad species has been inadequate. Common garden studies are useful for determining the influence of genetics on leaf traits because of the homogeneous environment among experimental units. To date, there have been no common garden studies which included all ten genera of cycads. The full phylogenetic breadth has, therefore, not been included in this important area of study. Methods We examined macronutrient and micronutrient content of leaves from one representative species from each of the ten cycad genera at Nong Nooch Tropical Botanical Garden in Thailand. Nitrogen content was determined by dry combustion, and the remaining nutrients were quantified by spectrometry. Results The least variable elements were nitrogen and phosphorus, and the most variable elements were boron and sodium. Nutrient content based on leaflet area was more variable than based on leaflet mass, reflecting species differences in specific leaf area. There were no universal macronutrient or micronutrient signals indicating clear phylogenetic distinctions. Implications for Conservation: Active management of threatened cycad taxa requires research to develop the knowledge to enable evidence-based decisions. This common garden study inclusive of all 10 cycad genera creates a foundation to determine leaf nutrient sufficiency ranges to inform management decisions.
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Damascos, Maria Angélica, Carlos Cesar Ronquim, and Carlos Henrique Britto Assis Prado. "Gas exchange and plant growth after defoliation on Leandra lacunosa, a cerrado woody species with continuous leaf production." Brazilian Archives of Biology and Technology 48, no. 6 (November 2005): 967–74. http://dx.doi.org/10.1590/s1516-89132005000800013.
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Morphological and physiological leaf traits were studied on control and defoliated potted Leandra lacunosa young plants. After defoliation, remaining bottom leaves showed no significant change in net photosynthesis and stomatal conductance values with time, but the leaf transpiration rate was higher. The production of the new leaves was greater after defoliation in top defoliated plants. Bottom defoliated plants increased stem extension rates and net photosynthesis transitorily. Two months after defoliation, control and defoliated plants did not differ in stem length and root dry mass values. In spite of smaller area and photosynthetic capacity, remaining bottom leaves were able to compensate top leaves elimination. The effectiveness of this compensatory response, however, depended on the ability of new leaves to escape from herbivores.
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Begum, Abida, and S. Harikrishna. "Evaluation of Some Tree Species to Absorb Air Pollutants in Three Industrial Locations of South Bengaluru, India." E-Journal of Chemistry 7, s1 (2010): S151—S156. http://dx.doi.org/10.1155/2010/398382.
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With the fast growing and excessive increase in industrial projects in Bengaluru, the level of pollution is also increasing. Metal-accumulating woody species have been considered for phytoextraction of metal-contaminated sites. The study examined the air pollution tolerance indices (APTI) of plant species around three industrial areas of south Bengaluru. The physiological and biochemical parameters, which are relative to leaf's water content (RWC), ascorbic acid content (AA), total leaf chlorophyll (TCh) and leaf extract pH were used to compute the APTI values and three heavy metals were selected (cadmium, lead and zinc) for analysis. The result shows that the most tolerant tree species with respect to ATPI and heavy metal concentration wereFicus religiosa, Azadirachta indicaandPongamia pinnata (L.). These plants can be considered as tolerant species in the industrial areas. The APTI values for remaining species are reported lower and are considered as sensitive species. Further studies on air pollution tolerance index with respect to three industrial areas of south Bengaluru indicated that the air pollution was maximum in Jigani industrial area and minimum in Electronic city.
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Meyer, G. A. "Mechanisms promoting recovery from defoliation in goldenrod (Solidago altissima)." Canadian Journal of Botany 76, no. 3 (March 1, 1998): 450–59. http://dx.doi.org/10.1139/b98-004.
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Plant responses to defoliation were examined using Solidago altissima and a leaf-chewing beetle (Trirhabda sp.). Plants were exposed to five intensities of defoliation (ranging from 0 to 85% leaf area loss) and effects on carbon gain, vegetative growth, and flowering were determined. Defoliated plants partially restored their capacity for carbon gain in the following ways: (i) activity of damaged leaves remaining after defoliation was increased via delayed senescence and enhanced photosynthetic rates and (ii) regrowth leaves on damaged plants had higher specific leaf area (leaf area per leaf mass) than comparable leaves on undamaged plants, but photosynthetic rates per unit area were equivalent to controls; thus, these leaves covered more area for a given investment in biomass with no loss in activity per unit area. Delayed leaf senescence and compensatory photosynthesis are commonly observed following defoliation, but increased specific leaf area is not generally recognized as a mechanism contributing to plant regrowth. In spite of these changes, total carbon gain capacity of defoliated plants was still less than that of controls after 3 weeks of regrowth. Overall plant performance was reduced by defoliation. Defoliated stems grew at a slower rate early in the season, added fewer new leaves in the first few weeks after defoliation, and had fewer lateral stems throughout the season. Damaged plants delayed flowering and maintained height growth later into the season than undamaged plants. Damaged stems reached heights comparable with undamaged stems by the end of the season, but they were thinner and their flower production was lower. Declines in plant growth and flowering were linear functions of the percentage leaf area loss, suggesting that even low levels of insect feeding are likely to affect plant performance.Key words: Solidago altissima, Trirhabda, defoliation, compensatory photosynthesis, insect herbivory, herbivore damage, plant compensation.
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Uieda, VS, and EM Carvalho. "Experimental manipulation of leaf litter colonization by aquatic invertebrates in a third order tropical stream." Brazilian Journal of Biology 75, no. 2 (May 2015): 405–13. http://dx.doi.org/10.1590/1519-6984.15013.
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Through a manipulative experiment, the colonization of leaf litter by invertebrates was investigated in two sections of a tropical stream (spatial scale) that differed in function of the canopy cover, one with the presence (closed area) and another without riparian vegetation (open area), during one month of the dry and one of the wet season (temporal scale). The work aimed to verify differences related to four variables: season, canopy cover, leaf type and leaf condition. Litter bags containing arboreal and herbaceous leaves (leaf type variable), non-conditioned and preconditioned (leaf condition variable) were placed at the bottom of the stream in each area (canopy cover variable) and season (dry and wet), and removed after 13-day colonization. The analysis of the remaining litter dry mass per leaf bag emphasizes differences related mainly to seasonality, canopy cover and leaf type, although leaf condition was also important when combined with those three factors. Comparing the abundance of invertebrates per treatment, there was a tendency of high predominance of Chironomidae during the dry season and greater taxa diversity and evenness during the wet season, when the water flow increase could alter the availability of microhabitats for local fauna. Even though canopy cover alone was not a significant source of variation in the abundance of invertebrates, the results showed a tendency of a combined effect of canopy cover with seasonality and leaf condition.
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Dodds, Darrin M., Daniel B. Reynolds, Joseph H. Massey, M. Cade Smith, and C. H. Koger. "Effect of Adjuvant and Urea Ammonium Nitrate on Bispyribac Efficacy, Absorption, and Translocation in Barnyardgrass (Echinochloa crus-galli). II. Absorption and Translocation." Weed Science 55, no. 5 (October 2007): 406–11. http://dx.doi.org/10.1614/ws-06-147.1.
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Inconsistent control of barnyardgrass with bispyribac may be alleviated through adjuvant technology. Experiments were conducted to determine the effect of adjuvant and urea ammonium nitrate (UAN) on absorption and translocation of bispyribac in barnyardgrass. Additional experiments were conducted to determine when maximum absorption and translocation occurred with the use of a methylated seed oil/organosilicone adjuvant (MSO/OSL) plus UAN (0.37 L ha−1 and 2% v/v). In the initial experiment, 14C-bispyribac–treated leaves, nontreated leaves, and roots were collected 6 and 24 h after application. Absorption was greatest with tank-mixed MSO/OSL (0.37 L ha−1) plus UAN (2% v/v) and the proprietary blend of MSO/OSL/UAN (2% v/v) at 80 and 74% of applied 14C-bispyribac, respectively. Translocation to nontreated leaves and roots was also highest with these treatments. Increased translocation appeared to be due to greater herbicide absorption, not an increase in translocation rate. The addition of 32% UAN to MSO/OSL and nonionic organosilicone (OSL/NIS) adjuvant systems resulted in a four to fivefold increase in absorption compared with treatments without UAN. Recovery of 14C-bispyribac in additional experiments generally decreased as time after application increased; however, recovery was 86% or greater for all time intervals. By 12 h after application, 68% of applied 14C-bispyribac was absorbed. At this time, 14C-bispyribac was partitioned within the plant in the following manner: 48% in the treated area, 10% in leaf tissue from treated area to tip of the treated leaf, 1.9% in leaf tissue from treated area to collar region of the treated leaf, 1.6% in remaining leaves from collar of treated leaf upward, 5.3% in remaining leaves from collar of treated leaf downward to soil line, and 0.7% in the roots. These data indicate that maximum absorption was achieved within 12 h with a tank mix of MSO/OSL and UAN or the MSO/OSL/UAN blend.
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Mączyńska, Agnieszka, Mariola Głazek, and Barbara Krzyzińska. "Effect of foliar fertilizer and fungicidal protection against leaf spot diseases on winter wheat." Acta Agrobotanica 58, no. 1 (2012): 51–58. http://dx.doi.org/10.5586/aa.2005.008.
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Field experiments were carried out in the seasons 2000/2001 and 2001/2002 in Plant Protection Institute, Sooenicowice Branch to assess the influence of foliar fertilizers such as Ekolist PK 1, Ekolist Mg, Mikrosol Z and Urea on healthiness of winter wheat. Foliar fertilizers were mixed with fungicides. The fungicides were applied at full or half recommended doses. The effect of the disease on wheat leaves was evaluated three times in each vegetation season. Remaining green leaf area (GLA) of leaves was also determined. GLA of the leaves F-1 was not significantly different for each combination with different fertilization and different levels of chemical treatment. The application of foliar fertilizer only had no effect on green leaf area (GLA). The results indicate that foliar fertilization of all experimental plots improved leaf condition and therefore halted the development of wheat leaf diseases. The increases of 1000 grain mass and yield was high for each plot where a fertilizer and a full or half dose of a fungicide was applied. Foliar fertilizing with no chemical control had no proven effect on studied parameters.
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Liu, Guangzhou, Yunshan Yang, Wanmao Liu, Xiaoxia Guo, Jun Xue, Ruizhi Xie, Bo Ming, Keru Wang, Peng Hou, and Shaokun Li. "Leaf Removal Affects Maize Morphology and Grain Yield." Agronomy 10, no. 2 (February 13, 2020): 269. http://dx.doi.org/10.3390/agronomy10020269.
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Increasing planting density is an important practice associated with increases in maize yield, but densely planted maize can suffer from poor light conditions. In our two-year field experiments, two morphologically different cultivars, ZD958 (less compact) and DH618 (more compact), were planted at 120,000 plants ha−1 and 135,000 plants ha−1, respectively. We established different leaf area index (LAI) treatments by removing leaves three days after silking: (1) control, no leaves removed (D0); (2) the two uppermost leaves removed (D1); (3) the four uppermost leaves removed (D2); (4) the leaves below the third leaf below the ear removed (D3); (5) the leaves of D1 and D3 removed (D4); (6) the leaves of D2 and D3 removed (D5). Optimal leaf removal improved light distribution, increased photosynthetic capacity and the post-silking source-sink ratio, and thus the grain yield, with an average LAI of 5.9 (5.6 and 6.2 for ZD958 and DH618, respectively) for the highest yields in each year. Therefore, less-compact cultivars should have smaller or fewer topmost leaves or leaves below the ear that quickly senesce post-silking, so as to decrease leaf area and thus improve light distribution and photosynthetic capacity in the canopy under dense planting conditions. However, for more compact cultivars, leaves below the ear should senesce quickly after silking to reduce leaf respiration and improve the photosynthetic capacity of the remaining top residual leaves. In future maize cultivation, compact cultivars with optimal post-silking LAI should be adopted when planting densely.
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Fu, Wei, Xingyuan He, Sheng Xu, Wei Chen, Yan Li, Bo Li, Lili Su, and Qin Ping. "Changes in nutrients and decay rate of Ginkgo biloba leaf litter exposed to elevated O3 concentration in urban area." PeerJ 6 (March 5, 2018): e4453. http://dx.doi.org/10.7717/peerj.4453.
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Ground-level ozone (O3) pollution has been widely concerned in the world, particularly in the cities of Asia, including China. Elevated O3 concentrations have potentially influenced growth and nutrient cycling of trees in urban forest. The decomposition characteristics of urban tree litters under O3 exposure are still poorly known. Ginkgo biloba is commonly planted in the cities of northern China and is one of the main tree species in the urban forest of Shenyang, where concentrations of ground-level O3 are very high in summer. Here, we hypothesized that O3 exposure at high concentrations would alter the decomposition rate of urban tree litter. In open-top chambers (OTCs), 5-year-old G. biloba saplings were planted to investigate the impact of elevated O3 concentration (120 ppb) on changes in nutrient contents and decomposition rate of leaf litters. The results showed that elevated O3 concentration significantly increased K content (6.31 ± 0.29 vs 17.93 ± 0.40, P < 0.01) in leaves of G. biloba, significantly decreased the contents of total phenols (2.82 ± 0.93 vs 1.60 ± 0.44, P < 0.05) and soluble sugars (86.51 ± 19.57 vs 53.76 ± 2.40, P < 0.05), but did not significantly alter the contents of C, N, P, lignin and condensed tannins, compared with that in ambient air. Furthermore, percent mass remaining in litterbags after 150 days under ambient air and elevated O3 concentration was 56.0% and 52.8%, respectively. No significant difference between treatments was observed in mass remaining at any sampling date during decomposition. The losses of the nutrients in leaf litters of G. biloba showed significant seasonal differences regardless of O3 treatment. However, we found that elevated O3 concentration slowed down the leaf litter decomposition only at the early decomposition stage, but slightly accelerated the litter decomposition at the late stage (after 120 days). This study provides our understanding of the ecological processes regulating biogeochemical cycles from deciduous tree species in high-O3 urban area.
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Camlin, Theodore E. "UPLAND/INLAND SPILL RESPONSE: USE OF UNDERFLOW DAMS." International Oil Spill Conference Proceedings 2001, no. 2 (March 1, 2001): 1381–89. http://dx.doi.org/10.7901/2169-3358-2001-2-1381.
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ABSTRACT On December 20, 1999 at approximately 1045 hours, crude oil was discovered in the Leaf River near Collins, Mississippi. The investigation determined the discharge was approximately 8,000 barrels originating from a source in the vicinity of State Highway 28 and Summerland Road, Jones County, Mississippi. The point of the release was located inland and in an upland type environment approximately 8 miles from the discovery location (Highway 84 bridge) near Collins, Mississippi. After the line was shut-in and control of the source was certain, it was determined there were three distinct types of work areas remaining for the cleanup operations: an upland marsh type environment, an ephemeral flow creek bed, and a limited access river environment. Strategic objectives for the response included prevention of any further migration of oil down the Leaf River; and prevent any additional oil from migrating or being flushed (during the next rain event) out of the upland marsh area down the unnamed creek and entering the Leaf River. The focus of this paper is on the measures pursued by operations and the Unified Command that were designed to prevent any further oiling of the Leaf River in the event oil was flushed out of the upper marshy area as a result of the cleanup operations or from a rain event. Operations installed a series of underflow dams at the confluence of the unnamed creek and the Leaf River as well as between the unnamed creek and the upland marsh area. These two stopgaps provided the necessary containment for the anticipated rain events forecast to occur early in the new year. The series of dams were successful in controlling the total fluid flow, containing flushed oil, and preventing additional oiling of the Leaf River during the first rain and throughout the remainder of the response.
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Delhomez, Nathalie, Odile Carisse, Michel Lareau, and Shahrokh Khanizadeh. "Susceptibility of Strawberry Cultivars and Advanced Selections to Leaf Spot Caused by Mycosphaerella fragariae." HortScience 30, no. 3 (June 1995): 592–95. http://dx.doi.org/10.21273/hortsci.30.3.592.
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Seventeen strawberry (Fragaria ×ananassa Duchesne) cultivars and six selections were tested under greenhouse conditions for susceptibility to leaf spot induced by Mycosphaerella fragariae (Tul.) Lindau. The level of susceptibility was evaluated based on maximum disease severity and area under the disease progress curve (AUDPC). The 23 genotypes were ranked based on AUDPC and grouped according to their susceptibility. Cluster analysis for AUDPC gave four groups corresponding to low, moderate, high, and very high susceptibility to leaf spot. `Annapolis', `Chambly', `Glooscap', `Redcoat', and `Veestar' consistently showed a low level of susceptibility. The selections SJ89700-1 and SJ8518-11 and `Tribute' showed a very high level of susceptibility, and the remaining cultivars were grouped as either moderately or highly susceptible.
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Xue, A. G., J. C. Sutton, A. Dale, and J. A. Sullivan. "Differences in virulence of Diplocarpon earlianum isolates on selected strawberry cultivars." Phytoprotection 77, no. 3 (April 12, 2005): 113–18. http://dx.doi.org/10.7202/706107ar.
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Eight isolates of Diplocarpon earlianum were evaluated for virulence, measured as the ability to produce percent leaf area with symptoms (LAS), on 18 cultivars of strawberry (Fragaria x ananassa). Significant differences were observed from isolate and cultivar effects, and isolate x cultivar interaction. Four of the eight isolates, on the average of 18 strawberry cultivars, had LAS ranging from 6.7-9.6%, and were classified as a group of low virulence. The remaining four isolates had LAS ranging from 25.9-45.8% and formed a high virulence group. Of the cultivars tested, 'Vibrant' was resistant and 'Micmac' was susceptible to all isolates in both virulence groups; 'Honeoye', 'Redcoat', 'Scotland', 'St. Clair' and 'Vantage' were resistant to the low virulence group, but had differential interactions to isolates in the high virulence group; the remaining 11 cultivars were susceptible to the high virulence group, but had differential interactions to isolates in the low virulence group. It is suggested that a number of different pathogen isolates are required to test strawberry genotypes for leaf scorch resistance. A leaf disk assay was developed in this study and can be used for laboratory evaluations of strawberry genotypes for susceptibility to D. earlianum.
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Zhou, Chang Wei, and Xing Yuan He. "Urban Forests Carbon Storage and Sequestration Benefits in Changchun City, Based on i-Tree Model." Advanced Materials Research 573-574 (October 2012): 471–74. http://dx.doi.org/10.4028/www.scientific.net/amr.573-574.471.
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The study area and plant 928786 trees, of which the most enjoy trees, accounting for about 45.6% of the total number of trees in the city. Eight of the region in the study area covered 2.7-7.9% of trees. Salix matsudana, Populus pseudo-simonii, Pinus sylvestnis var. mongolica Litv, Pinus tabulaeformis var.mukdensis Uyeki and Prunus persica f. rubro-plena is the most important species, they represent 32.2% of the number of all the trees, leaves area of 50.6% and 43.1% of the leaf biomass. The city a lot of trees concentrated in diameter at breast height 15.3-38.1 cm. In general, the tree is younger Changchun city (50.7% of DBH less than 23 cm). A large part of Changchun city area (accounting for 54% of the whole city) is by impervious material, asphalt, cement, stone cover, and the remaining 46% is permeable ground, herb areas, lawns and a small proportion of the pond, artificial lakes and rivers.
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Combe, Laurette. "Nouvelle méthode de suivi au champ de la sénescence des feuilles de maïs." Canadian Journal of Botany 83, no. 8 (August 1, 2005): 941–53. http://dx.doi.org/10.1139/b05-043.
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A new method was developed to describe and quantify leaf senescence in a field-grown maize canopy with the purpose of future crop modelling. Leaf shape was analysed using the outlines of over 500 adult leaves from plants grown under diverse culture conditions. Leaf width (λ) taken at regular distances from the ligule (L) allowed the development of leaf-shape equations. These are third-degree polynomials. Thus, four leaf measurements are needed for characterizing leaf shape: maximum width (λm), total length (Lt), width at ligule level (λo), and distance from ligule to the point of maximum width (Lx). Assuming y = (λ/λm) and x = (L/Lt), the shape equation can be written as y = (1 x)(ax2 + bx + yo). Coefficients a and b were estimated from (λo/λm) = yo and (Lx/Lt) = xm. The leaf area between the ligule and any point on the midrib can be obtained by analytically integrating the leaf shape equation. In the present work, degreening was used as the indicator of senescence. Thus, once the shape equation was been defined, easily taken measurements of “green colour” allowed me to calculate the remaining green area by leaf. The vertical profile of the green area on the whole plant could then be described. The time course of green leaf area in a field-grown maize canopy was analysed from silking up to harvest. The farther the leaves were from the ear and the lower they were in the plant, the earlier they lost their green colour. The smallest leaves fully changed colour in 1 week, while this process took 2 weeks for the largest ones. A whole plant lost its green colour in about 5 weeks. Drought caused earlier but not faster leaf degreening. Low plant densities delayed discoloration of the leaves close to the ear, even under drought conditions. The start of senescence in leaves 716 was almost simultaneous in all crop conditions, but it could not be determined whether this was due to a threshold effect of the source/sink ratio or to another factor. This method was easy to set up for field studies with maize, but it could be also used for studies on other graminaceous species and some broad-leaved species. It could be extended to describe the physiological functioning over the leaf length and across the vertical profile of the whole plant. Key words: leaf shape, leaf area, leaf senescence, leaf color, maize, plant density, drought.
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Ávila, Crébio José, and José Roberto Postali Parra. "Leaf consumption by Diabrotica speciosa (Coleoptera: Chrysomelidade) adults on difFerent host plants." Scientia Agricola 60, no. 4 (December 2003): 789–92. http://dx.doi.org/10.1590/s0103-90162003000400028.
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Studies related to the feeding behavior of pest insects provide information that will aid the development of control tactics. Leaf consumption by Diabrotica speciosa adults fed on bean, corn, potato and soybean was determined in the laboratory under free-choice (multiple or double-choice) and no-choice (confinement) conditions. In the multiple-choice tests leaf circles were randomly arranged in a circular pattern (arena) inside Petri dishes. The degree of preference for the hosts was determined under double-choice conditions, where common bean was considered the standard host and the remaining plants (soybean, potato and corn) as test hosts. In all trials, two Diabrotica speciosa couples were released and maintained within the dish for 24 hours; the leaf area consumed by the insects was determined after this feeding period. Food type (host) influenced leaf area consumption by D. speciosa adults both in free-choice and in no-choice tests (P < 0.05). Under free-choice conditions, the insects preferred to feed on bean rather than on soybean, potato or corn, with no differences among these last three host plants (P > 0.05). As to the no-choice test, the consumption was higher for corn than for potato, probably to compensate the low nutritional quality of the first host.
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Fournioux, Jean-Claude. "Demonstration and study of characters of foliar « compensatory growth» phenomenon in grapevine (Vitis vinifera L.)." OENO One 30, no. 2 (June 30, 1996): 53. http://dx.doi.org/10.20870/oeno-one.1996.30.2.1109.
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<p style="text-align: justify;">Defoliation and decapitation experiments showed that the growth of a grapevine leaf was inhibited by both the terminal bud and the younger higher leaves. There is a phenomenon of synergy between these two influences. A young leaf freed of these two influences showed a higher growth rate than the norm ; this is « compensatory growth ». It is when a leaf is in its phase of maximal growth that it is most able to realize this &laquo compensatory growth ». This is not due to a longer growth time, but more to a faster growth rate. This « compensatory growth » is not the consequence of competition between leaf growth and internodal elongation. Exogenous applications of auxins prevented or restricted this growth; gibberellic acid had no effect. These results partly explain those of other authors who demonstrate that reduction in the leaf area of a vine is accompanied by an increase in photosynthetic efficiency of the remaining leaves.</p>
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Ali, Shahid, B. B. Kumar, C. M. Kalleshwara Swamy, M. S. Kadian, and B. V. Ramakrishna. "Studies on feasibility of sustainable quality seed potato production technology and development of supply chain for the benefit of small and marginal potato growers of Karnataka." Journal of Horticultural Sciences 13, no. 1 (June 30, 2018): 72–81. http://dx.doi.org/10.24154/jhs.2018.v13i01.008.
Full textAbstract:
Management of aphid vectors in potato is important for the production of quality seed potato. Aphids are the major vectors of many potato viruses which transmit viral diseases limiting the seed potato production. To explore the area with aphid free/low population a weekly aphid observation was made in major potato growing areas of Chikkaballapur and Chickmagalur districts during rabiand kharif seasons to assess the build-up trends on the standing crop using aphid-leaf count and catches of yellow water pan and yellow sticky traps. Aphid population was below threshold level in the areas surveyed, however in Chickmagalur aphid build-up was erratic due to heavy rain fall followed by dry spells. Harvested potato in Chikkaballapur was treated and stored in cold storage for three months. During June, 50 per cent of the seed stock was transported to Chickmagalur area for planting in kharif season and remaining seed was used for planting in Chikkaballapur area during rabi season. In Chickmagalur, the harvested and treated seed was stored in low cost country potato store for three months and 50 per cent seed from warehouse was transported to Chikkaballapur for rabi planting and remaining seed was planted in Chickmagalur area during November thereby saving nearly 40 per cent of seed cost. Thus, the feasibility supply chain has been established making the local potato growers self-sustainable in quality seed potato production resulting in 30-40 percent seed requirement met locally produced quality seed and non-traditional areas will be brought under potato cultivation. The breeder seed was multiplied under low cost insect proof net houses during rabi season in Chikkaballapur area, harvested seed was stored in cold storage thereafter distributed among the local potato growers for planting during kharif season in Chickmagalur area.
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Portillo-Estrada, Miguel, Mari Pihlatie, Janne F. J. Korhonen, Janne Levula, Arnoud K. F. Frumau, Andreas Ibrom, Jonas J. Lembrechts, et al. "Climatic controls on leaf litter decomposition across European forests and grasslands revealed by reciprocal litter transplantation experiments." Biogeosciences 13, no. 5 (March 16, 2016): 1621–33. http://dx.doi.org/10.5194/bg-13-1621-2016.
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Abstract. Carbon (C) and nitrogen (N) cycling under future climate change is associated with large uncertainties in litter decomposition and the turnover of soil C and N. In addition, future conditions (especially altered precipitation regimes and warming) are expected to result in changes in vegetation composition, and accordingly in litter species and chemical composition, but it is unclear how such changes could potentially alter litter decomposition. Litter transplantation experiments were carried out across six European sites (four forests and two grasslands) spanning a large geographical and climatic gradient (5.6–11.4 °C in annual temperature 511–878 mm in precipitation) to gain insight into the climatic controls on litter decomposition as well as the effect of litter origin and species. The decomposition k rates were overall higher in warmer and wetter sites than in colder and drier sites, and positively correlated with the litter total specific leaf area. Also, litter N content increased as less litter mass remained and decay went further. Surprisingly, this study demonstrates that climatic controls on litter decomposition are quantitatively more important than species or site of origin. Cumulative climatic variables, precipitation, soil water content and air temperature (ignoring days with air temperatures below zero degrees Celsius), were appropriate to predict the litter remaining mass during decomposition (Mr). Mr and cumulative air temperature were found to be the best predictors for litter carbon and nitrogen remaining during the decomposition. Using mean annual air temperature, precipitation, soil water content and litter total specific leaf area as parameters we were able to predict the annual decomposition rate (k) accurately.
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LIN, Kuan-Hung, Chun-Wei WU, and Yu-Sen CHANG. "Applying Dickson Quality Index, Chlorophyll Fluorescence, and Leaf Area Index for Assessing Plant Quality of Pentas lanceolata." Notulae Botanicae Horti Agrobotanici Cluj-Napoca 47, no. 1 (October 20, 2018): 169–76. http://dx.doi.org/10.15835/nbha47111312.
Full textAbstract:
Plant quality greatly relates to the seedling vigor (SV), survival and growth of plants after transplantation. The objective of this study was to use the nondestructive measurements of chlorophyll fluorescence (ChlF) and leaf area index (LAI) as SV indices for star cluster (Pentas lanceolata). Plants were grown in potting soil under nature sunlight for 90 d. A total of 13 morphological and physiological parameters were selected for measurements. Among them, root growth potential (RGP) was the best predictor for SV in all tested plants. Plants were separated into 5 RGP groups based on the number of new roots, and remaining parameters were also separated into those same levels. The trends and rates of increase from levels 1 to 5 in Dickson quality index (DQI), LAI, total dry mass, and ChlF were all similar to the RGP index. Although RGP and DQI are frequently used as indices for SV, these measurements are time-consuming and require sample destruction. Consistent and strongly high correlations were observed among DQI, LAI, and ChlF, demonstrating the applicability of these indices for measuring SV in star cluster. The measurements of LAI and ChlF were predicted using multiple variables from validation datasets, and showed novel and useful parameters for examining the SV of star cluster.
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Portillo-Estrada, M., M. Pihlatie, J. F. J. Korhonen, J. Levula, A. K. F. Frumau, A. Ibrom, J. J. Lembrechts, et al. "Biological and climatic controls on leaf litter decomposition across European forests and grasslands revealed by reciprocal litter transplantation experiments." Biogeosciences Discussions 12, no. 21 (November 11, 2015): 18053–84. http://dx.doi.org/10.5194/bgd-12-18053-2015.
Full textAbstract:
Abstract. Projection of carbon and nitrogen cycles to future climates is associated with large uncertainties, in particular due to uncertainties how changes in climate alter soil turnover, including litter decomposition. In addition, future conditions are expected to result in changes in vegetation composition, and accordingly in litter type and quality, but it is unclear how such changes could potentially alter litter decomposition. Litter transplantation experiments were carried out across 6 European sites (4 forest and 2 grasslands) spanning a large geographical and climatic gradient (5.6–11.4 °C in annual temperature 511–878 mm in precipitation) to gain insight into biological (litter origin and type, soil type) and climatic controls on litter decomposition. The decomposition k rates were overall higher in warmer and wetter sites than in colder and drier sites, and positively correlated to the litter total specific leaf area. Also, litter N content increased as less litter mass remained and decay went further. Surprisingly, this study demonstrates that climatic controls on litter decomposition are quantitatively more important than species, litter origin and soil type. Cumulative climatic variables, precipitation and air temperature (ignoring days with air temperatures below 0 °C), were appropriate to predict the litter remaining mass during decomposition (Mr). And Mr and cumulative air temperature were found to be the best predictors for litter carbon and nitrogen remaining during decomposition. We concluded with an equation for predicting the decomposition k rate by using mean annual air temperature and litter total specific leaf area.
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Jett, Lewis W., and T. P. Talbot. "GROWTH CHARACTERISTICS OF `BEAUREGARD' AND `DARBY' SWEETPOTATO." HortScience 31, no. 5 (September 1996): 759d—759. http://dx.doi.org/10.21273/hortsci.31.5.759d.
Full textAbstract:
`Beauregard' and `Darby' sweetpotato cultivars were developed and released by the Louisiana Agricultural Experiment Station in 1987 and 1994, respectively. In total acreage, `Beauregard' is the dominant cultivar of sweetpotato grown in Louisiana and the remaining United States. However, very little is known about the growth characteristics of these two cultivars. Therefore, the objectives of this research were to examine storage root and shoot growth. Uniform transplants of both cultivars were transplanted in mid-July 1995 at the LSU Sweet Potato Research Station and sequentially harvested biweekly. Optimum leaf area of both cultivars was attained ≈60 days after transplanting. `Beauregard' had less leaf area than `Darby' at each stage of development, but partitioned more assimilates to the storage roots. At harvest, the harvest index of `Beauregard' was ≈75% compared with 50% for `Darby'. `Beauregard' had a significantly greater total yield of storage roots than `Darby'.
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Pinkard, E. A., and C. L. Beadle. "Aboveground biomass partitioning and crown architecture of Eucalyptus nitens following green pruning." Canadian Journal of Forest Research 28, no. 9 (September 1, 1998): 1419–28. http://dx.doi.org/10.1139/x98-119.
Full textAbstract:
The effects of green pruning on aboveground biomass partitioning and crown architecture were explored in a 3-year-old Eucalyptus nitens (Deane and Maiden) Maiden plantation. Responses were measured in five height zones and three foliage age classes over a 20-month period following removal of 0, 50, or 70% of the green crown length. Development of foliage in the upper crowns of 50%-pruned trees was faster and total leaf area at the end of the experiment was greater than in unpruned trees. Leaf area development of 70%-pruned trees was similar to that of unpruned trees. Larger apical leaves, with a lower specific leaf area (SLA), developed following 50% pruning. However, 70% pruning resulted in smaller leaves, and SLA increased in some crown positions. Pruning reduced branch diameter and length in the upper crowns. However, branches of 50%-pruned trees had an increased ratio of foliage to wood dry mass. These responses to green pruning may have increased the carbon-fixing capacity and the efficiency of carbon utilisation of the remaining crown. Following 50% pruning, responses were sufficient to maintain stem dry mass increment at a level similar to that of unpruned trees. However, following 70% pruning, stem and branch dry mass increment was reduced.
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Sharma, Y., and S. Sharma. "Effect of sowing dates on genetic components in six-rowed barley." Acta Agronomica Hungarica 56, no. 3 (September 1, 2008): 349–56. http://dx.doi.org/10.1556/aagr.56.2008.3.11.
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The genetics of yield and related traits was studied in barley ( Hordeum vulgare L.) by means of 10 × 10 half-diallel progenies (F 1 and F 2 ) at three sowing dates. An additive-dominance model fitted only for flag leaf area, spike length and 1000-grain weight at different sowing dates. Both additive (D) and dominance components (H 1 and H 2 ) were significant for all the traits studied, indicating the preponderance of dominance components in controlling the inheritance for these traits. The value of (H 1 /D) 1/2 indicated over-dominance for all the traits except for flag leaf area. Values of ‘F’ indicated an excess of dominant alleles in the parents for all traits except for flag leaf area. The environmental component ‘E’ was significant for all traits. The ratio of H 2 /4H 1 indicated the symmetrical distribution of genes for all the traits studied. The value of h 2 /H 2 was less than one for all traits except for spike length, suggesting that a dominant gene was involved in controlling the inheritance of spike length, whereas multiple genes controlled the inheritance of the remaining traits. The heritability estimates were relatively moderate for flag leaf area and 1000-grain weight, but low for all other traits. However, epistatic interactions had an important role in the expression of other traits. Breeding methods such as bi-parental mating in early segregating generations or diallel selective mating may be advantageous to combine important yield component characters for a tangible advance in six-rowed barley.
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Mutisya, J. M., J. A. Sullivan, J. C. Sutton, J. Zheng, and S. Couling. "Influence of leaf scorch on vegetative growth and yield of three strawberry (Fragaria × ananassa Duch.) cultivars with differing levels of resistance." Canadian Journal of Plant Science 85, no. 3 (July 1, 2005): 679–86. http://dx.doi.org/10.4141/p04-122.
Full textAbstract:
Three strawberry cultivars, Kent, Jewel and Blomidon, were evaluated for their reaction to leaf scorch (Diplocarpon earlianum) disease. The three cultivars are considered to be susceptible, moderately resistant and resistant to leaf scorch, respectively. Plants were grown in the field in a runnerless culture system and inoculated with conidial suspensions at one of five concentrations to generate a range of disease severities. The control plants were not innoculated. Disease severity was monitored during the establishment year and these data were used to calculate area under the disease progress curves (AUDPC) for each cultivar. At dormancy, vegetative growth analysis was performed on a sample of plants from each plot. The remaining plants were overwintered and data were collected on yield and yield components the following season. The difference in AUDPC values between control and highest levels of the disease for Kent, Jewel and Blomidon were 31.6, 26.0 and 25.2 units, respectively. Leaf scorch reduced photosynthetically active leaf area in all three cultivars, which reduced dry matter accumulation. The vegetative characters most affected were leaf area and number, crown number and dry weight and root dry weight. At the highest level of disease attained total yield declined 58, 41 and 31 g plant-1 corresponding with disease severities of 44.5, 36.4 and 32.4 units AUDPC for Kent, Jewel and Blomidon, respectively. This represented a 20–21% yield reduction in each cultivar. Fruit number was the yield component most sensitive to the leaf scorch disease. A strong relationship was established between highest disease severity during late summer and fall (which includes the time of flower bud initiation) and yield the following season. Key words: Diplocarpon earlianum, foliar disease, June-bearing
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Pande, S., and J. Narayana Rao. "Resistance of Wild Arachis Species to Late Leaf Spot and Rust in Greenhouse Trials." Plant Disease 85, no. 8 (August 2001): 851–55. http://dx.doi.org/10.1094/pdis.2001.85.8.851.
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Seventy-four accessions of wild Arachis species along with a susceptible line TMV 2 belonging to A. hypogaea were evaluated for resistance to late leaf spot and rust under greenhouse environment. The experiment was conducted twice to confirm the resistance of the accessions. Percentage of leaf area damaged and disease score on a 1 to 9 scale for late leaf spot and rust were recorded for all accessions in both experiments. Additionally, percentage of defoliation was recorded for late leaf spot. One accession, ICG 8190, of A. hoehnei and one accession, ICG 13199, of A. duranensis were asymptomatic to late leaf spot in both experiments. In addition, 26 accessions were classified as resistant, 10 accessions were moderately resistant, and the remaining 36 accessions exhibited a susceptible reaction to late leaf spot. Only one accession, ICG 8954 of A. kuhlmannii, remained asymptomatic to rust in both experiments. All other accessions, except ICG 8206 of A. ipaensis, ICG 8197, ICG 8198, ICG 11549, and ICG 13178 of A. monticola, and ICG 13171 of A. stenosperma were classified as highly resistant to rust. Four accessions of A. monticola were susceptible to late leaf spot and rust.
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Bell, M. "The effect of foliage pathogens on growth of peanuts (Arachis hypogaea L.) in tropical Northern Australia." Australian Journal of Agricultural Research 37, no. 1 (1986): 31. http://dx.doi.org/10.1071/ar9860031.
Full textAbstract:
The effect of foliage pathogens on growth and development and final yield of Virginia Bunch peanuts was assessed under tropical wet season conditions in the Ord River Irrigation Area. Applications of the fungicides chlorothalonil and benomyl were used to manipulate onset and severity of disease during the season. Heavy disease pressure in unprotected plots caused severe defoliation and a 30% reduction in commercial yield. This yield reduction, associated with significantly lower pod numbers, was probably due to defoliation causing reduced interception of incident photosynthetically active radiation (PAR) during pod fill and reduced efficiency of conversion of intercepted PAR to reproductive yield. The latter was due to the effect of foliage pathogens on either photosynthetic capacity of remaining leaves, or patterns of assimilate distribution. Data on PAR interception and remaining leaf area alone did not adequately explain the effects of foliage pathogens on crop yield. Canopies with maximum disease control maintained leaf area indices well in excess of that necessary for full interception of incident radiation until maturity. However, commercial yields of pods and kernels from these plots were significantly lower than for those with intermediate foliage protection. This effect was probably due to altered patterns of assimilate distribution between vegetative and reproductive plant parts. The rate of increase in kernel size in fully protected plots was lower than in those with less effective pathogen management, so that a greater proportion of the total pod yield consisted of small, immature pods which were lost during the commercial threshing process.
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Rodríguez, Diego, Laura Vega, Ángel Murillo, and Eduardo Peralta. "Pathogenic variability of Pseudocercospora griseola isolates from two provinces of Ecuador." Journal of Agriculture of the University of Puerto Rico 101, no. 1 (January 31, 2017): 107–19. http://dx.doi.org/10.46429/jaupr.v101i1.14297.
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Common bean (Phaseolus vulgaris L.) is the most important edible grain legume in Ecuador. The Ministry of Agriculture, Cattle Raising, Aquaculture and Fisheries of this country estimated that 71,600 hectares were cultivated in 2012; of the sown area, 53% was dedicated to dry grain and the remaining 47% to fresh grain. Beans are an important source of income for farmers and food for thousands of Ecuadorian families. Crop performance and yield are affected by diseases such as angular leaf spot caused by Pseudocercospora griseola (Sacc.) Ferraris. The best alternative for disease control is to use resistant varieties. However, durability of field resistance will depend on the knowledge of angular leaf spot variability. In Ecuador, detailed and systematic studies on the variability of the angular leaf spot pathogen have not been conducted. For this reason, the pathogenic variability of 21 isolates of angular leaf spot, collected from the provinces of Carchi and Imbabura in the Ecuadorian Andes, was studied. Thirteen different pathotypes were identified, five of them showed compatibility with only the group of Andean differentials and the remaining eight showed compatibility with two groups of differentials (Andean and Mesoamerican). Race 63:0 was the most frequent and race 31:63 was the most virulent. None of the isolates were compatible with differential Cornell 49-242. Therefore, bean breeding lines in Ecuador would benefit by incorporating the Phg-2 resistance gene present in differential Cornell 49-242 .
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Nijman, Vincent, and S. (Bas) van Balen. "A faunal survey of the Dieng Mountains, Central Java, Indonesia: distribution and conservation of endemic primate taxa." Oryx 32, no. 2 (April 1998): 145–56. http://dx.doi.org/10.1046/j.1365-3008.1998.d01-24.x.
Full textAbstract:
A faunal survey was conducted in May–September 1994 and June–July 1995 in the Dieng Mountains, one of the last remaining larger patches of forest in CentralJava province, Indonesia. All three primate species endemic to the Javan faunal region – Javan gibbon Hylobates moloch, grizzled leaf monkey Presbytis comata and ebony leaf monkey Trachypithecus auratus – were found to be present. Hylobates moloch occurs only in the lowland and hill forests in the western part of the study area, while the other two species were found throughout the area from lowland to montane forests. Although more research needs to be done onhabitat preferences and densities at which the primates occur, the available data suggestthat the Dieng Mountains may harbour the second largest populations of both H. moloch and P. comata in the same location. In order to safeguard these two endangered primates itis suggested that the reserve system in Java be expanded to include the Dieng Mountains.
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Viedma, Olga, Danilo R. A. Almeida, and Jose Manuel Moreno. "Postfire Tree Structure from High-Resolution LiDAR and RBR Sentinel 2A Fire Severity Metrics in a Pinus halepensis-Dominated Burned Stand." Remote Sensing 12, no. 21 (October 30, 2020): 3554. http://dx.doi.org/10.3390/rs12213554.
Full textAbstract:
Tree and plant structures remaining after fires reflect well their degree of consumption, and are therefore good indicators of fire severity. Satellite optical images are commonly used to estimate fire severity. However, depending on the severity of a fire, these sensors have a limited ability to penetrate the canopy down to the ground. Airborne light detection and ranging (LiDAR) can overcome this limitation. Assessing the differences between areas that have been burned in different fire severities based on satellite images of plant and tree structures remaining after fires is important, given its widespread use to characterize fires and fire impacts (e.g., carbon emissions). Here, we measured the remaining tree structures after a fire in a forest stand burned in SE Spain in the summer of 2017. We used high-resolution LiDAR data, acquired from an unmanned aerial vehicle (UAV) six months after the fire. This information was crossed with fire severity levels based on the relativized burnt ratio (RBR) derived from Sentinel 2A images acquired a few months before and after fire. LiDAR tree structure data derived from vertical canopy profiles (VCPs) were classified into three clusters, using hierarchical principal component analysis (HPCA), followed by a random forest (RF) to select the most important variables in distinguishing the cluster groups. Among these, crown leaf area index (LAI), crown leaf area density (LAD), crown volume, tree height and tree height skewness, among others, were the most significant variables, and reflected well the degree of combustion undergone by the trees based on the response of these variables to variations in fire severity from RBR Sentinel 2A. LiDAR metrics were able to distinguish crown fire from surface fire through changes in the understory LAI and understory and midstory vegetation. The three tree structure clusters were well separated among each other and significantly related with the RBR Sentinel 2A-derived fire severity categories. Unburned and low-severity burned areas were more diverse in tree structures than moderate and high severity burned ones. The LiDAR metrics derived from VCPs demonstrated promising potential for characterizing fine-grained post-fire plant structures and fire damage when crossed with satellite-based fire severity metrics, turning into a promising approach for better characterizing fire impacts at a resolution needed for many ecological processes.
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Grier, Charles C. "Foliage loss due to snow, wind, and winter drying damage: its effects on leaf biomass of some western conifer forests." Canadian Journal of Forest Research 18, no. 9 (September 1, 1988): 1097–102. http://dx.doi.org/10.1139/x88-168.
Full textAbstract:
Damage to forest canopies by wind, snow, or winter desiccation significantly reduced stand leaf biomass and area below "steady-state" levels in several western coniferous forests. Leaf biomass of 12 different western conifer forests sampled for an average of 4 years was reduced by as much as 36.3, 34.5, and 42.2% by single wind damage, snow breakage, or winter desiccation events, respectively, during the sampling interval. Foliage loss exceeded annual foliage production as estimated from leaf litterfall in about half the stands where damage occurred. Production efficiency (Mg dry matter•ha−1•year−1•Mg−1 foliage) by remaining foliage appeared to increase after damage. Based on the data available, major canopy damage appears to occur at roughly 9- to 16-year intervals in western coniferous forests. However, this canopy damage is epidosic and unpredictable. Such damage adds an additional measure of uncertainty to forest productivity models.
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Thomas, Andrew L., Jackie L. Harris, Elijah A. Bergmeier, and R. Keith Striegler. "Establishment Technique and Rootstock Impact ‘Chambourcin’ Grapevine Morphology and Production in Missouri." HortTechnology 27, no. 2 (April 2017): 248–56. http://dx.doi.org/10.21273/horttech03610-16.
Full textAbstract:
An evaluation of establishment techniques and rootstocks for ‘Chambourcin’ hybrid grape (Vitis sp.) was conducted 2009–12. Our objective was to evaluate four establishment methods and their interactions with grafted and ungrafted vines in terms of vine morphology and early fruit production under southwest Missouri conditions. The study was established in May 2009, as a factorial experiment comparing four establishment methods (open-trained without protection—two shoots, grow tube protected—two shoots, paperboard carton protected—two shoots, and fan-trained without protection—six shoots) across two vine types (own-rooted and grafted to ‘Couderc 3309’ hybrid grape rootstock). All vines in four of 12 field replications were destructively harvested near the conclusion of the first growing season, with leaf area and total vine dry matter determined. In years 3 and 4, yield, fruit composition, and vegetative growth were determined from the eight remaining replications. The fan training method increased leaf area and total vine dry matter compared with the other methods, but none of the establishment techniques affected fruit yield. Trunks that were tube protected had longer internodes, smaller diameter, and less dry matter, whereas both protection devices reduced glyphosate injury. Vine type (grafted and ungrafted) did not impact total leaf area or dry weight during the establishment year, but grafted vines had increased trunk and root shank dry weights compared with own-rooted vines. Grafted vines produced greater fruit yield in 2012. The fan training method required more labor to execute; although it was successful at increasing leaf area and root dry weight, it increased susceptibility to glyphosate injury and did not promote increased precocity or early fruit yield.
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Pompelli, MF, SCV Martins, EF Celin, MC Ventrella, and FM DaMatta. "What is the influence of ordinary epidermal cells and stomata on the leaf plasticity of coffee plants grown under full-sun and shady conditions?" Brazilian Journal of Biology 70, no. 4 (November 2010): 1083–88. http://dx.doi.org/10.1590/s1519-69842010000500025.
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Stomata are crucial in land plant productivity and survival. In general, with lower irradiance, stomatal and epidermal cell frequency per unit leaf area decreases, whereas guard-cell length or width increases. Nevertheless, the stomatal index is accepted as remaining constant. The aim of this paper to study the influence of ordinary epidermal cells and stomata on leaf plasticity and the influence of these characteristics on stomata density, index, and sizes, in the total number of stomata, as well as the detailed distribution of stomata on a leaf blade. As a result, a highly significant positive correlation (R²a = 0.767 p < 0.001) between stomatal index and stomatal density, and with ordinary epidermal cell density (R²a = 0.500 p < 0.05), and a highly negative correlation between stomatal index and ordinary epidermal cell area (R²a = -0.571 p < 0.001), were obtained. However in no instance was the correlation between stomatal index or stomatal density and stomatal dimensions taken into consideration. The study also indicated that in coffee, the stomatal index was 19.09% in shaded leaves and 20.08% in full-sun leaves. In this sense, variations in the stomatal index by irradiance, its causes and the consequences on plant physiology were discussed.
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Xue, A. G., and T. D. Warkentin. "Partial resistance to Mycosphaerella pinodes in field pea." Canadian Journal of Plant Science 81, no. 3 (July 1, 2001): 535–40. http://dx.doi.org/10.4141/p00-103.
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The responses of 335 field pea lines originating from more than 30 countries to mycosphaerella blight caused by Mycosphaerella pinodes were evaluated in inoculated field plots in 1994 and 1995. Seven lines (Baccara, Carneval, Danto, Majoret, Miko, PI273605, and Yellowhead) with low area under the disease progress curve (AUDPC) scores were identified. These seven lines, along with the resistant check, Radley, and the susceptible check, 89–195, were further examined for components of partial resistance to the disease in 1996 and 1998. Components evaluated were leaf area with symptoms (LAS), stem area with symptoms (SAS), pod area with symptoms (PAS), and percent seed infection (SI). Differences among pea lines were found in all components. Compared with the susceptible check, Carneval had significantly lower LAS, PAS, and SI in both years and was considered partially resistant to leaf, pod, and seed infection; Danto had significantly lower LAS, SAS, and PAS and was partially resistant to leaf, stem, and pod infection; Yellowhead had significantly lower SAS, PAS, and SI and was partially resistant to stem, pod, and seed infection; Majoret had significantly lower LAS and SAS and was partially resistant to leaf and stem infection; Miko had significantly lower SAS and PAS and was partially resistant to stem and pod infection; PI273605 had significantly lower PAS and SI and was partially resistant to pod and seed infection; and Baccara and Radley had significantly lower SAS and were partially resistant to stem infection only. Plots of Baccara and Yellowhead inoculated with M. pinodes-infected stubble had 10 and 17% reduction in yield, respectively, compared with non-inoculated and fungicide-treated plots and, thus, were considered tolerant to the disease. The remaining lines had yield reductions of 30 to 49%. Key words: Mycosphaerella blight, Mycosphaerella pinodes, Pisum sativum, field pea, partial resistance, disease tolerance
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Page, D. S., E. S. Gilfillan, J. C. Foster, J. R. Hotham, and L. Gonzalez. "MANGROVE LEAF TISSUE SODIUM AND POTASSIUM ION CONCENTRATIONS AS SUBLETHAL INDICATORS OF OIL STRESS IN MANGROVE TREES." International Oil Spill Conference Proceedings 1985, no. 1 (February 1, 1985): 391–93. http://dx.doi.org/10.7901/2169-3358-1985-1-391.
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ABSTRACT As part of an ongoing study of the long-term effects of the Zoe Colocotroni oil spill of March 17, 1973, in Bahia Sucia, Puerto Rico, the effects of the remaining oil on the red mangrove trees in the impact area were investigated. This study involved four sampling trips to the spill site and a reference area outside the spill zone between April 1979 and April 1981. The present study was based on the observation that stressed mangrove trees in the heavily oil-affected areas had a similar appearance to trees exhibiting stress due to hypersalinity in unoiled areas. The working hypothesis was that petroleum hydrocarbons induce stress in salt-excluding plants such as red mangroves by disrupting the ability of the roots to exclude ions from seawater. Measurements of sodium (the principal seawater cation) and potassium (a major physiological ion) were made on leaf samples taken from trees from oil-affected areas and reference areas. Sediment core samples were taken from the root zone of the trees sampled at each site and analyzed for hydrocarbons by gravimetric and gas chromatographic methods. The results show a relationship between sediment hydrocarbon concentration and the ratio of sodium to potassium for mangrove leaves sampled at each site. The results show that for trees exposed at the root zone to the least weathered oil, the values of this ratio for the leaves had the largest values, reflecting an oil-induced impairment of the salt (Na) exclusion mechanism. This approach to measuring the physiological health of mangrove trees at an oil spill site offers a potentially useful means of documenting oil stress and recovery from oil stress in salt-excluding halophytes. Because oil stress in mangroves appears to be a root membrane-directed effect, there may be a “window in time” between initial oil impact and plant damage, as oil penetrates the sediments, during which mitigation measures could be taken.
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Cheng, Lailiang, Guohai Xia, and Terry Bates. "Growth and Fruiting of Young `Concord' Grapevines in Relation to Reserve Nitrogen and Carbohydrates." Journal of the American Society for Horticultural Science 129, no. 5 (September 2004): 660–66. http://dx.doi.org/10.21273/jashs.129.5.0660.
Full textAbstract:
One-year-old `Concord' grapevines (Vitis labruscana Bailey) were fertigated with 0, 5, 10, 15, or 20 mm nitrogen by using a modified Hoagland's solution for 8 weeks during active vine growth in summer. Half of the vines at each N concentration were sprayed with 3% foliar urea twice in late September while the rest served as controls. After natural leaf fall, all the vines were overwintered in a cold room (2 to 4 °C). Four vines from each treatment were destructively sampled before budbreak for reserve N and carbohydrate analysis. The remaining vines were supplied with either no N or sufficient N (10 mm N) from 2 weeks before bloom to 1 month after bloom. All the vines were destructively harvested at 1 month after bloom. Total amount of N in dormant vines increased with increasing N fertigation concentration. Total nonstructural carbohydrates (TNC) increased with increasing N fertigation concentration from 0 to 10 mm, and then leveled off with further rises in N supply. Foliar urea application increased total N but decreased TNC of dormant vines at each given N fertigation level. When no N was provided during the regrowth period, vine total leaf area, fruit yield, and total dry weight increased with increasing N supply from fertigation the previous year. Vines sprayed with foliar urea the previous fall produced a larger total leaf area, a higher yield, and a higher total vine dry weight at each given N fertigation concentration. Providing vines with sufficient N during the regrowth period significantly increased total leaf area, fruit yield, and vine total dry weight across the previous N fertigation concentrations, but vines sprayed with foliar urea still had a larger leaf area, a higher yield, and a higher total vine dry weight at each given N fertigation concentration. Therefore, we conclude that both vegetative growth and fruiting of young `Concord' vines are largely determined by reserve nitrogen, not by reserve carbohydrates, and that current-season N supply plays a very important role in sustaining vine growth and development, especially fruit growth.
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Berbec, A., and D. Laskowska. "Investigations of IsogenomicAlloplasmics of Flue-Cured Tobacco Nicotianatabacum cv. Wislica." Beiträge zur Tabakforschung International/Contributions to Tobacco Research 21, no. 5 (April 1, 2005): 259–63. http://dx.doi.org/10.2478/cttr-2013-0791.
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AbstractCytoplasms of fifteen wild Nicotianae and a male sterile cytoplasm (cms) from N. tabacum were bred into the genome of a standard Polish flue-cured cultivar Wislica. The sixteen iso-genomic alloplasmics were compared for expression of male sterility and for some traits related to field performance. In cmsN. bigelovii, N. debneyi, N. exigua, N. megalosiphonor N. suaveolens stamens were absent, in cmsN. tabacum, N. glauca, N. goodspeedii or N. undulata stamens were absent or rudimentary, in cmsN. eastii, N. glutinosa or N. plumbaginifoliastamen tissue became petaloid, in those from N. knightiana and N. raimondiithey were morphologically normal. Female organ morphology was changed in cmsN. goodspeedii, N. occidentalis, N. exigua, N. debneyior N. bigelovii, seed set was reduced only in cmsN. occidentalis. Plant height in most alloplasmics was similar to that of the fertile variety but was strongly depressed by the cytoplasms of N. glutinosa, N. eastiiand N. plumbaginifolia. Leaf area was positively affected by N. amplexicaulis, N. bigeloviiand N. undulatacytoplasms, unaffected by N. suaveolens, N. tabacumand N. glaucacytoplasms and negatively affected by the remaining cytoplasms mostly because of the narrowing of the leaf blade. Cured leaf yields from cmsN. bigelovii were higher than those of Wislica. Leaf yields from cmsN. amplexicaulis, N. suaveolens, N. glauca or N. tabacum were not affected by the alien cytoplasm, whereas those from the remaining alloplasmics were depressed to different extents. Increased incidence of PVY and white spots (mostly attributable to Cercospora sp.) were observed on many of the alloplasmics especially on cmsN. exigua and N. suaveolens(PVY) and increased white spots only on cmsN. bigelovii, N. exigua, N. occidentalis and N. undulata.
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Silva, Antônio Veimar da, Carla Michelle da Silva, Caio Nunes Gonçalves, Manoel Cícero de Oliveira Filho, Caike de Sousa Pereira, Maria Jany Kátia Loiola Andrade, and Wagner Rogério Leocádio Soares Pessoa. "Productive potential of watermelon under different plant spacings in the semi-arid region of Brazil." Australian Journal of Crop Science, no. 15(02):2021 (February 3, 2021): 238–43. http://dx.doi.org/10.21475/ajcs.21.15.02.p2796.
Full textAbstract:
This study aimed to evaluate the growth and development of watermelon plants under different plant spacings in the Semi-arid region of Brazil. A randomized block experimental design was used with four treatments and eight replications. Data were submitted to analysis of variance and the Tukey test. The treatments were composed by the following spacings: T1: 3.0 x 0.8 m; T2: 3.0 x 0.6 m; T3: 2.0 x 0.8 m and T4: 2.0 x 0.6 m (spacings between rows and between plants, respectively). The plant length, number of leaves, stem diameter, leaf area, number of flowers, number of fruits per plant, average fruit weight, total fruit production, number of commercial fruits, average weight of commercial fruits, total weight of commercial fruits and percentage of commercial fruits were evaluated in this study. There was a significant difference in the growth traits: stem diameter and leaf area at 30 days after sowing (DAS), and plant length, stem diameter and number of leaves at 60 DAS, with no significant statistical difference in the remaining days and nor for the number of flowers. The watermelon plants showed adequate vegetative and productive development at the 2.0 x 0.8 m plant spacing in the edaphoclimatic conditions of the semi-arid region under study. This spacing is well suited to small producers in the semi-arid region, which are dependent on agriculture with small areas and can obtain good productivity with no need to use larger areas due to spacing
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RIGHI, CIRO ABBUD, VINCENT COUDERC, CARLOS RODRIGUES PEREIRA, and HILTON THADEU ZARATE COUTO. "RESPONSES OF EUCALYPTUS CAMALDULENSIS SPROUTS TO SHADE: AN EVALUATION OF CANOPY PLASTICITY." Experimental Agriculture 52, no. 3 (June 16, 2015): 346–58. http://dx.doi.org/10.1017/s0014479715000137.
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SUMMARYEucalyptus spp. is the main tree used in cellulose production worldwide, cultivated mostly in extensive monocrop plantations. However, due to concerns on environmental impacts, fear on decrease of food production related to the size of cultivated area, its location near human settlements with few jobs generation, eucalypt cultivation is no longer encouraged in many places. At the same time, large plantations hold the opportunity to integrate eucalypt into agroforestry systems (AFS) in a variety of production systems with many social, economical and environmental advantages. In this study we studied canopy modifications of E. camaldulensis sprouts under different degrees of shade. The plants were located on a gradient of available solar irradiation ranging from 51 to 94%. E. camaldulensis showed canopy plasticity with modified radiation interception patterns under diverse irradiations. Most of these variations were of small amplitude with some important variables remaining almost unchanged (leaf density, canopy percentage, tree, trunk and canopy height) or increasing only slightly (leaf area index and canopy opening). The main changes presented by E. camaldulensis, with a steep increase towards full sun, were: foliage area, canopy surface, canopy volume and area of canopy projection. In order to design appropriate agroforestry systems with young eucalypt growing under the shade of other crops, it is necessary to determine at which point the observed variable changes can support reasonable production.