Journal articles on the topic 'Plants canopies'
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1
FINNIGAN, J. J. "Waving plants and turbulent eddies." Journal of Fluid Mechanics 652 (May 19, 2010): 1–4. http://dx.doi.org/10.1017/s0022112010001746.
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New large-eddy simulations of flow over a flexible plant canopy by Dupont et al. (J. Fluid Mech., 2010, this issue, vol. 652, pp. 5–44) have produced apparently paradoxical results. Work over the last three decades had suggested that turbulent eddies could ‘lock onto’ to the waving frequency of uniform cereal canopies. Their new simulations contradict this view, although a resolution may lie in the essentially three-dimensional nature of the instability process that generates the dominant eddies above plant canopies.
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Beeson*, Richard C. "Response of Individual Plant Actual Evapotranspiration to Canopy Closure: A Three Dimensional Model Derived from Viburnum odoratissimum." HortScience 39, no. 4 (July 2004): 857A—857. http://dx.doi.org/10.21273/hortsci.39.4.857a.
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ng production and in landscapes, woody plants are initially spaced apart to develop to desirable landscape quality. As plants grow and canopies begin to interact, canopies transform from individual isolated canopies to one large, closed canopy system. Changes in individual plant actual evapotranspiration (ETA) during the transitions between isolated and closed canopies are 30% on average. Such changes can have a substantial impact on supplemental irrigation requirements, both decreasing with closure and increasing with random removal of plants from a closed canopy. Data will be presented demonstrating changes in ETA as canopy closure progresses from isolated plants through 33%, 67%, and 100% canopy closure. Concurrent data from plants of marketable size grown in 3.8, 10.4, and 26.6 L containers were used to evaluate effects of canopy vertical thickness, and total canopy height, on the changes in ETA relative to degree of canopy closure. Contributions to ETA at 100% canopy closure and isolated plants from leaves at various depths within a canopy will be discussed.
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Méndez-Toribio, Moisés, Ana María González-Di Pierro, Mauricio Quesada, and Julieta Benítez-Malvido. "Regeneration beneath a dioecious tree species (Spondias purpurea) in a Mexican tropical dry forest." Journal of Tropical Ecology 30, no. 3 (March 10, 2014): 265–68. http://dx.doi.org/10.1017/s0266467414000066.
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Abstract:In dioecious plant species different frugivore activity between genders may influence the abundance and richness of the seedling banks underneath their canopies throughout seed removal and dispersal. In the tropical dry forest of Chamela, on the Pacific Coast of Mexico, the role of S. purpurea female trees as nucleation sites of regeneration was investigated. The standing density, species richness and dispersal syndrome of woody seedlings (i.e. trees and shrubs, 10–100 cm tall) recruited underneath and outside the canopy of 10 male and 10 female S. purpurea trees were recorded in a total of 160 1-m2 plots. Total density was greater in seedling communities associated with female trees (i.e. underneath and outside their canopies) as compared with male trees (231 vs. 153 seedlings, respectively); whereas overall species richness was greater underneath female canopies. Further, the density of zoochorous species were greater underneath the canopy of S. purpurea females (range = 0–5 plants m−2), than elsewhere (outside female canopies, range = 0–3 plants m−2; underneath and outside male canopies, range = 0–2 plants m−2), suggesting a directional dispersal bias towards them. Females of dioecious plant species may act as nucleation sites of initial seedling recruitment in tropical dry forests.
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Zubair, Muhammad, Akash Jamil, Syed Bilal Hussain, Ahsan Ul Haq, Ahmad Hussain, Din Muhammad Zahid, Abeer Hashem, Abdulaziz A. Alqarawi, and Elsayed Fathi Abd_Allah. "Diversity of Medicinal Plants among Different Tree Canopies." Sustainability 13, no. 5 (March 2, 2021): 2640. http://dx.doi.org/10.3390/su13052640.
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The moist temperate forests in Northern Pakistan are home to a variety of flora and fauna that are pivotal in sustaining the livelihoods of the local communities. In these forests, distribution and richness of vegetation, especially that of medicinal plants, is rarely reported. In this study, we carried out a vegetation survey in District Balakot, located in Northeastern Pakistan, to characterize the diversity of medicinal plants under different canopies of coniferous forest. The experimental site was divided into three major categories (viz., closed canopy, open spaces, and partial tree cover). A sampling plot of 100 m2 was established on each site to measure species diversity, dominance, and evenness. To observe richness and abundance, the rarefaction and rank abundance curves were plotted. Results revealed that a total of 45 species representing 34 families were available in the study site. Medicinal plants were the most abundant (45%) followed by edible plants (26%). Tree canopy cover affected the overall growth of medicinal plants on the basis of abundance and richness. The site with partial canopy exhibited the highest diversity, dominance, and abundance compared to open spaces and closed canopy. These findings are instrumental in identifying the wealth of the medicinal floral diversity in the northeastern temperate forest of Balakot and the opportunity to sustain the livelihoods of local communities with the help of public/private partnership.
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Schuerger, Andrew C., Kenneth L. Copenhaver, David Lewis, Russell Kincaid, and George May. "Canopy structure and imaging geometry may create unique problems during spectral reflectance measurements of crop canopies in bioregenerative advanced life support systems." International Journal of Astrobiology 6, no. 2 (April 2007): 109–21. http://dx.doi.org/10.1017/s147355040700376x.
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AbstractHuman exploration missions to the Moon or Mars might be helped by the development of a bioregenerative advanced life-support (ALS) system that utilizes higher plants to regenerate water, oxygen and food. In order to make bioregenerative ALS systems competitive to physiochemical life-support systems, the ‘equivalent system mass’ (ESM) must be reduced by as much as possible. One method to reduce the ESM of a bioregenerative ALS system would be to deploy an automated remote sensing system within plant production modules to monitor crop productivity and disease outbreaks. The current study investigated the effects of canopy structure and imaging geometries on the efficiency of measuring the spectral reflectance of individual plants and crop canopies in a simulated ALS system. Results indicate that canopy structure, shading artefacts and imaging geometries are likely to create unique challenges in developing an automated remote sensing system for ALS modules. The cramped quarters within ALS plant growth units will create problems in collecting spectral reflectance measurements from the nadir position (i.e. directly above plant canopies) and, thus, crop canopies likely will be imaged from a diversity of orientations relative to the primary illumination source. In general, highly reflective white or polished surfaces will be used within an ALS plant growth module to maximize the stray light that is reflected onto plant canopies. Initial work suggested that these highly reflective surfaces might interfere with the collection of spectral reflectance measurements of plants, but the use of simple remote sensing algorithms such as 760/685 band ratios or normalized difference vegetation index (NDVI) images greatly reduced the effects of the reflective backgrounds. A direct comparison of 760/685 and NDVI images from canopies of lettuce, pepper and tomato plants indicated that unique models of individual plants are going to be required to properly assess the health conditions of canopies. A mixed model of all three plant species was not effective in predicting plant stress using either the 760/685 or NDVI remote sensing algorithms.
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Soter, Steven. "Radiocarbon Anomalies from Old CO2 in the Soil and Canopy Air." Radiocarbon 53, no. 1 (2011): 55–69. http://dx.doi.org/10.1017/s0033822200034354.
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The canopies of forests and cultivated fields can retard the ventilation of CO2 respired from the soil. The plants in dense canopies can then acquire a small fraction of their carbon by recycling some of the respired CO2. Furthermore, some plants can assimilate a small fraction of their carbon by uptake of CO2 in the soil via their roots. In tectonically active areas, the diffuse flux of CO2 from geological sources may be comparable to that from normal soil respiration. In such areas, both the canopy and root uptake effects may allow plants to acquire a measurable fraction of their carbon from geological sources. Because this “old” carbon lacks radiocarbon, its assimilation would increase the apparent 14C ages of the plants. These effects may account for some of the discrepancies between archaeological and 14C dates.
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Darfis, Irwan, and Aprisal Aprisal. "FAKTOR-FAKTOR EKSTERNAL YANG MEMPENGARUHI WAKTU PEMBUAHAN MANGGIS." Jurnal Solum 6, no. 2 (July 2, 2009): 66. http://dx.doi.org/10.25077/js.6.2.66-73.2009.
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A research aiming to evaluate external factors affecting fertility process on manggo trees had been conducted in Lima Puluh Kota Regency, as one of production central for manggos in West Sumatra. In the first year, the activity of the research was aimed to identification on earlier and later flowering plants. External factors being identified were soil nutrients and soil chemical characteristics, as well as temperature and relative humidity around canopies of the trees. The results showed that there was an interaction among the external factors on the characteristics of both groups of the manggo trees. Earlier flowering plants had higher temperature around the canopies, but lower relative humidity than those later flowering plants. Some other external factors such as light intensity as well as the duration of day and night period will be identified on the following research.Key Words: Manggos tree, canopy temperature and humidity, earlier flowering plants, later flowering plants
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Lindig-Cisneros, Roberto, and Joy B. Zedler. "Phalaris arundinacea seedling establishment: effects of canopy complexity in fen, mesocosm, and restoration experiments." Canadian Journal of Botany 80, no. 6 (June 1, 2002): 617–24. http://dx.doi.org/10.1139/b02-042.
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Phalaris arundinacea L. (reed canary grass) is a major invader of wetlands in temperate North America; it creates monotypic stands and displaces native vegetation. In this study, the effect of plant canopies on the establishment of P. arundinacea from seed in a fen, fen-like mesocosms, and a fen restoration site was assessed. In Wingra Fen, canopies that were more resistant to P. arundinacea establishment had more species (eight or nine versus four to six species) and higher cover of Aster firmus. In mesocosms planted with Glyceria striata plus 1, 6, or 15 native species, all canopies closed rapidly and prevented P. arundinacea establishment from seed, regardless of the density of the matrix species or the number of added species. Only after gaps were created in the canopy was P. arundinacea able to establish seedlings; then, the 15-species treatment reduced establishment to 48% of that for single-species canopies. A similar experiment in the restoration site produced less cover of native plants, and P. arundinacea recruited more readily. Results suggest that, where conditions are favorable for native plant growth, even species-poor canopies can inhibit P. arundinacea establishment from seed, but when disturbances create gaps, species-rich canopies confer greater resistance to invasion.Key words: diversity, establishment, fen, invasion resistance, species richness, wetlands.
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Mugunga, C. P., and D. T. Mugumo. "Acacia sieberiana Effects on Soil Properties and Plant Diversity in Songa Pastures, Rwanda." International Journal of Biodiversity 2013 (November 4, 2013): 1–11. http://dx.doi.org/10.1155/2013/237525.
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Effects of A. sieberiana trees on soil properties and plant diversity were investigated in Songa pastures, Rwanda. Tree characteristics and crown architecture of A. sieberiana were studied. Soil properties were assessed and plants were identified under and away from tree crowns. Counts of individual plants/species were done only under tree crowns. Nitrogen, P, and K were analysed in the soil, grass, and A. sieberiana leaves. Plant diversity was determined using Simpson's diversity index. Data were subjected to ANOVA. Soil organic carbon (SOC), cation exchange capacity (CEC), Ca2+, N and pH, and plant diversity were higher in soils under tree canopies than in open areas. Tree leaves were significantly richer in N and poorer in P and K as compared to grasses. Tree crowns grew wider and horizontal and developed intertwined secondary branching, reducing light intensity to as low as 38% under tree canopies compared to the open pasture. At 3 trees/ha stocking, A. sieberiana trees shaded 0.18 ha and herbaceous plants and grasses unpalatable to livestock dominated under tree canopies. A tradeoff of A. sieberiana tree value versus the loss of palatable grass due to tree presence needs to be assessed to decide whether the trees should be included in pastures and if yes, the apporpriate stocking identified.
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Giuliani, Rita, and James A. Flore. "534 Use of Infrared Thermal Imagery for Ground-based and Real-time Detection of Water Deficit in Fruit Trees." HortScience 35, no. 3 (June 2000): 487D—487. http://dx.doi.org/10.21273/hortsci.35.3.487d.
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Ground-based infrared thermal imagery was applied for early detection of plant water deficit, i.e., before photosynthetic activity is depressed and before growth processes are negatively affected by water shortage. Remote and real-time sensing of radiative canopy surface temperature was performed in Michigan in Summer 1999 on peach and apple orchards, using a digital IR imaging radiometer. Still images and videos were acquired on single canopies of well-watered plants and plants subjected to water depletion. Atmospheric parameters were monitored simultaneously. On apple trees, the apparent canopy temperature showed a wider thermal dispersion [10 °C], compared to peach tree canopies [2–5 °C]. Central tendency and shape parameters describing the canopy thermal distribution could identify, even for apple canopies, the thermal signal [1–2 °C] of plant water deficit, before changes in leaf net photosynthetic rate and fruit diameter were observed. The results of this study support the application of digital infrared thermal imagery and image processing for early recognition of plant water deficit. The decrease of the cost of available thermographic cameras makes their use feasible.
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Messier, Christian, and Pierre Bellefleur. "Light quantity and quality on the forest floor of pioneer and climax stages in a birch–beech–sugar maple stand." Canadian Journal of Forest Research 18, no. 5 (May 1, 1988): 615–22. http://dx.doi.org/10.1139/x88-090.
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The quantity and quality of solar radiation (300 to 1100 nm) beneath forest canopies were compared on sunny (sunflecks excluded) and cloudy days between the pioneer and climax stages of a birch–beech–sugar maple stand, and among the main species within these two stages of succession. The climax stage (mature canopies) transmits less energy between 300 and 1100 nm and casts smaller red to far red ratios than the pioneer stage (5-year-old canopies) on both sunny and cloudy days. Moreover, the canopies of the main species within each of these two stages of succession do not transmit the same quantity and quality of solar radiation. All these differences are greater on cloudy than sunny days. Leaf transmittance varies among species but this alone does not explain the differences in canopy transmission among these same species. The results are discussed in relation to the ecological significance for the plants growing under birch–beech–sugar maple stands.
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Tikhomirov, Alexander A. "Intracanopy Lighting in Phytocenoses and Photobiological Efficiency of Radiation in Photoculture Conditions." Light & Engineering, no. 02-2021 (April 2021): 4–15. http://dx.doi.org/10.33383/2020-076.
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The review is devoted to the study of the internal radiation regime in the canopies cultivated under controlled environmental conditions. The expediency of using canopies as an object of research for evaluating the photobiological efficiency of radiation in light culture conditions is justified. The appropriateness of light measurements in multi-tiered canopies is shown, taking into account the role of leaves of different tiers in the formation of an economically useful crop. The main requirements for light devices for their use in measuring artificial radiation in light culture conditions are considered, and a brief analysis of the existing instrument base for performing these studies is given. A number of examples show the complexity and ambiguity of the internal structure of the light field that is forming within canopies in light culture conditions. Conceptual approaches to the choice of spectral and energy characteristics of artificial irradiation for plant light culture are proposed and justified. The necessity of taking into account the light conditions of leaves of different tiers when choosing the spectral and energy characteristics of light sources for the cultivation of multi-tiered canopies is justified. Techniques, methods, and light sources used for additional intracanopy lighting are analysed. The efficiency of using side illumination of plant canopies and conditions for its implementation are considered. The advantages of the volume distribution of canopies on the most common multi-tiered lighting installations are discussed. Based on the presented material, we consider ways to improve methodological approaches for evaluating the photobiological effectiveness of artificial radiation in light culture conditions for canopies of cultivated plants, taking into account the features of their architectonics and internal radiation regime.
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Guan, Zhen, Amr Abd-Elrahman, Vance Whitaker, Shinsuke Agehara, Benjamin Wilkinson, Jean-Philippe Gastellu-Etchegorry, and Bon Dewitt. "Radiative Transfer Image Simulation Using L-System Modeled Strawberry Canopies." Remote Sensing 14, no. 3 (January 24, 2022): 548. http://dx.doi.org/10.3390/rs14030548.
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The image-based modeling and simulation of plant growth have numerous and diverse applications. In this study, we used image-based and manual field measurements to develop and validate a methodology to simulate strawberry (Fragaria × ananassa Duch.) plant canopies throughout the Florida strawberry growing season. The simulated plants were used to create a synthetic image using radiative transfer modeling. Observed canopy properties were incorporated into an L-system simulator, and a series of strawberry canopies corresponding to specific weekly observation dates were created. The simulated canopies were compared visually with actual plant images and quantitatively with in-situ leaf area throughout the strawberry season. A simple regression model with L-system-derived and in-situ total leaf areas had an Adj R2 value of 0.78. The L-system simulated canopies were used to derive information needed for image simulation, such as leaf area and leaf angle distribution. Spectral and plant canopy information were used to create synthetic high spatial resolution multispectral images using the Discrete Anisotropic Radiative Transfer (DART) software. Vegetation spectral indices were extracted from the simulated image and used to develop multiple regression models of in-situ biophysical parameters (leaf area and dry biomass), achieving Adj R2 values of 0.63 and 0.50, respectively. The Normalized Difference Vegetation Index (NDVI) and the Red Edge Simple Ratio (SRre) vegetation indices, which utilize the red, red edge, and near infrared bands of the spectrum, were identified as statistically significant variables (p < 0.10). This study showed that both geometric (canopy seize metrics) and spectral variables were successful in modeling in-situ biomass and leaf area. Combining the geometric and spectral variables, however, only slightly improved the prediction model. These results show the feasibility of simulating strawberry canopies and images with inherent geometrical, topological, and spectral properties of real strawberry plants. The simulated canopies and images can be used in applications beyond creating realistic computer graphics for quantitative applications requiring the depiction of vegetation biological processes, such as stress modeling and remote sensing mission planning.
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Muth, Christine C., and F. A. Bazzaz. "Tree canopy displacement and neighborhood interactions." Canadian Journal of Forest Research 33, no. 7 (July 1, 2003): 1323–30. http://dx.doi.org/10.1139/x03-045.
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Competitive interactions among plants are largely determined by spatial proximity. However, despite their sessile nature, plants have the ability to avoid neighbors by growing towards areas with high resource availability and reduced competition. Because of this flexibility, tree canopies are rarely centered directly above their stem bases and are often displaced. We sought to determine how a tree's competitive neighborhood influences its canopy position. In a 0.6-ha temperate forest plot, all trees greater than 10 cm DBH (n = 225) were measured for basal area, height, canopy depth, and trunk position. Canopy extent relative to trunk base was determined in eight subcardinal directions, and this information was used to reconstruct canopy size, shape, and position. We found that trees positioned their canopies away from large neighbors, close neighbors, and shade-tolerant neighbors. Neighbor size, expressed as basal area or canopy area, was the best indication of a neighbor's importance in determining target tree canopy position. As neighborhood asymmetry increased, the magnitude of canopy displacement increased, and the precision with which canopies avoided neighbors increased. Flexibility in canopy shape and position appears to reduce competition between neighbors, thereby influencing forest community dynamics.
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Gleeson, Scott K., and F. Schieving. "Plato's Plant; On the Mathematical Structure of Simple Plants and Canopies." Journal of Vegetation Science 11, no. 4 (August 2000): 613. http://dx.doi.org/10.2307/3246592.
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Veselkin, D. V., D. I. Dubrovin, O. S. Rafikova, Y. A. Lipikhina, N. V. Zolotareva, E. N. Podgaevskaya, L. A. Pustovalova, and A. V. Yakovleva. "SHADING AND LIGHT INTERCEPTION IN THICKETS OF INVASIVE <i>ACER NEGUNDO </i>AND <i>SORBARIA SORBIFOLIA</i>." Russian Journal of Biological Invasions 14, no. 4 (November 26, 2021): 30–42. http://dx.doi.org/10.35885/1996-1499-2021-14-4-30-42.
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The aim of the work is to establish how greatly the light conditions change under the leaf canopy of two invasive plant species in the Middle Urals - Acer negundo and Sorbaria sorbifolia . In June - August 2020, using a portable light meter, 8370 measurements of illumination were performed in forest parks (at a height of 1.5 and 0.5 m, i.e. above and below the canopy of the leaves of the invasive shrub S. sorbifolia and the native shrub Rubus idaeus ; in random points under the canopies of Pinus sylvestris ; on glades, paths and forest edges) and in urban habitats (at a height of 1.5 m and 0.5 m in dense thickets of the invasive tree A. negundo and other tree species). The average illumination intensity was as following: under S. sorbifolia - 4 ± 1 lux × 10; under R. idaeus - 7 ± 1 lux × 10; in A. negundo thickets - 13 ± 2 lux × 10; in thickets of other tree species - 25 ± 4 lux × 10; under the canopies of urban pine forests - 80 ± 10 lux × 10; in the forest edges - 96 ± 14 lux × 10. In dense thickets, A. negundo intercepts about 94% of the light falling on its canopies, S. sorbifolia - about 93%. This is significantly higher than the light interception level in habitats used as control: other tree species canopies of greatly urbanized habitats intercept about 89%, the thickets of R. idaeus - about 82%. Thus, invasive plants reduce the amount of light available to other plant species in communities significantly more than native plants.
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Andrade, José Luis, Erick De la Barrera, Casandra Reyes-García, M. Fernanda Ricalde, Gustavo Vargas-Soto, and J. Carlos Crevera. "El metabolismo ácido de las crasuláceas: diversidad, fisiología ambiental y productividad." Botanical Sciences, no. 81 (June 4, 2017): 37. http://dx.doi.org/10.17129/botsci.1764.
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Mexico possesses a great species diversity of Crassulacean Acid Metabolism (CAM) plants. These plants can grow in places where water is infrequent, such as arid and semi-arid zones, and tree canopies, or as aquatic plants in places with low CO2 availability. This review presents methodological, evolutionary, ecological, and physiological aspects on CAM plants. Also, it shows data from recent studies related to the environmental effect on changes in the photosynthesis CAM. Finally, we made a consideration about the lack of studies on the physiology of CAM plants in Mexico despite its enormous diversity.
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Muth, Christine C., and F. A. Bazzaz. "Tree canopy displacement at forest gap edges." Canadian Journal of Forest Research 32, no. 2 (February 1, 2002): 247–54. http://dx.doi.org/10.1139/x01-196.
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Although plants are sessile organisms, they can forage for resources and avoid neighbors by growing towards areas with high resource availability and reduced competition. Apparently because of this morphological flexibility, tree canopies are rarely positioned directly above their stem bases and are often displaced. To determine if contrasts in light availability lead to the development of canopy displacement, we investigated the responses of tree canopies to the heterogeneous light environments at the edges of six experimental gaps. Canopies and trunks of gap edge trees were mapped, and their spatial distributions were analyzed. We found that tree canopies were displaced towards gap centers. The magnitude and precision of canopy displacement were greater for subcanopy trees than for canopy trees. The magnitude and precision of canopy displacement were generally greater for earlier successional trees and hardwoods than for later successional trees and conifers. Canopy depth was significantly greater on gap-facing sides of trees than on forest-facing sides of trees. Thus, trees along gap edges foraged for light by occupying both horizontal and vertical gap space. This morphological flexibility has implications for individual plant success, as well as forest structure and dynamics.
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Jackson, J., and A. J. Ash. "The role of trees in enhancing soil nutrient availability for native perennial grasses in open eucalypt woodlands of north-east Queensland." Australian Journal of Agricultural Research 52, no. 3 (2001): 377. http://dx.doi.org/10.1071/ar00012.
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To investigate the effects of eucalypt trees on pasture in open eucalypt woodlands of north-eastern Queensland, 2 common native pasture species, Chrysopogon fallaxand Heteropogon contortus, were grown in soil collected from under tree canopies and inter-canopy areas. These soils were collected from 2 localities that differed in soil fertility. The objective was to determine whether trees enhanced soil nutrient levels beneath their canopies and whether such changes affected pasture productivity and quality. It was hypothesised that tree effects would be greater when overall soil fertility was low. Shade and water stress treatments, which aimed to simulate field conditions, were also imposed to investigate their independent and interactive effects on plant growth. Chemical analyses showed that nutrient levels were higher in under-canopy soils, and plants grown in under-canopy soil produced 42% more biomass than plants in outside-canopy soil. This increase in biomass was significantly greater when the soil was from the low fertility site than from the high fertility site. Leaf quality, in terms of N and P concentration and dry matter digestibility (DMD), was generally higher in plants in under-canopy soil. Shading reduced plant root biomass but had no effects on above ground biomass or leaf quality. Water stress reduced above and below ground biomass and increased leaf quality. Shading and water stress effects were greater in plants in the more fertile soil types. Simulated ‘under-canopy’ plants (shaded, water-stressed plants in under-canopy soil) produced more biomass and had higher leaf N concentration and DMD than simulated ‘outside-canopy’ plants (unshaded, well-watered plants in outside-canopy soil). In a pastoral context, trees in tropical woodlands are generally considered in terms of their competitive effect on pasture productivity. This study has demonstrated that soil nutrient availability is enhanced under eucalypt canopies. The biomass results indicate that this effect is greater when overall soil fertility conditions are low. These enhanced soil nutrient conditions influence forage productivity and quality. Such positive benefits should be considered when management decisions are taken to remove or kill trees in eucalypt woodlands.
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Schuch, Ursula K., Jack J. Kelly, and Trent Teegerstrom. "Capillary Mats for Maintenance of Plants in the Retail Nursery." HortTechnology 18, no. 2 (January 2008): 250–55. http://dx.doi.org/10.21273/horttech.18.2.250.
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Capillary mats and overhead sprinkler irrigation were used in a simulated retail environment to maintain annual and perennial plants in containers for various time periods during summer and winter. Combining the results from both seasons, four species with dense canopies had larger canopy sizes when maintained on the capillary mats, three species requiring more drainage had larger canopies with overhead irrigation, and five species were unaffected by irrigation systems. Substrate electrical conductivity was higher for some species in winter for plants on capillary mats, conserving fertilizer compared with overhead irrigation. Most species tolerated either irrigation system well. Water application was 71% less in summer and 62% less in winter to maintain plants on capillary mats compared with overhead irrigation. An economic analysis compared the investment required for setup and maintenance of plants in a retail situation using hand watering, overhead sprinkler, or capillary mat irrigation. The partial budget indicates that capillary mats are a labor-saving alternative to hand watering in a retail nursery and will compensate for the higher initial investment within less than 1 year. The overhead sprinklers are the most cost-effective system of the three because of less costly initial set-up and maintenance than the capillary mats; however, they are not a true alternative to hand watering in a retail situation because they interfere with customer traffic and worker activities.
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Wright, GC, KT Hubick, and GD Farquhar. "Discrimination in Carbon Isotopes of Leaves Correlates With Water-Use Efficiency of Field-Grown Peanut Cultivars." Functional Plant Biology 15, no. 6 (1988): 815. http://dx.doi.org/10.1071/pp9880815.
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Variation in water-use efficiency (W, g of total dry matter produced/kg water used), and its correlation with cultivar isotope discrimination in leaves (Δ) was assessed in peanut plants grown in small canopies in the field. Plants were grown in separate minilysimeters that were both embedded in the ground and positioned above the crop. Differences among cultivars were found in W and � and the relationship between W and Δ was compared for plants grown in open and closed canopies. Genetic variability in W in plants grown in the field under non-limiting water conditions was demonstrated, with Tifton-8, of Virginia habit, having the highest W (3.71 g/kg) and Rangkasbitung, an Indonesian cultivar of Spanish habit, the lowest (2.46 g/ kg). Variability in W was due to variation in total dry matter production more than that of water use. A strong negative correlation was found between Δ and W, and also between Δ and total dry matter. The relationship between whole plant W, including roots, and Δ was stronger than that between shoot W, without roots and Δ. The improvement occurred because of variation among cultivars in the root to shoot ratio. This highlights the importance of taking account of root dry matter in studies concerning W. There were significant differences in W and Δ between plants in pots above-ground compared to pots in the ground, with above-ground plants having significantly lower values of both W and Δ. The ranking of W and Δ among cultivars was not affected by the contrast in environment, which suggests these parameters are under strong genetic control. Total above-ground dry matter yield at maturity was negatively correlated with Δ, while pod yield was not. It appears a negative association between harvest index and Δ may exist; however not all cultivars used in this and other studies follow this response. Both water-use efficiency, Wand total dry matter production are negatively correlated with Δ in leaves of peanut plants grown in small canopies in the field. Measurement of Δ may prove a useful trait for selecting cultivars with improved W and total dry matter yield under field conditions.
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Rodríguez, A., J. Durán, and A. Gallardo. "Influence of legumes on N cycling in a heathland in northwest Spain." Web Ecology 7, no. 1 (October 23, 2007): 87–93. http://dx.doi.org/10.5194/we-7-87-2007.
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Abstract. Nitrogen availability frequently limits plant growth in natural ecosystems. N-fixers should have a substantial competitive advantage in N-limited systems, and as a byproduct of their activity they should increase the quantity and availability of N in the system as a whole. However, this effect has rarely been quantified in natural ecosystems. Heathlands in northwest Spain are frequently occupied by legume scrubs. We tested whether the presence of these legumes affected the N cycle in these communities. Specifically, we addressed the following questions: is nitrogen availability higher beneath legume canopies than beneath non-legume canopies? Is soil microbial biomass acting as a sink of extra N mineralized beneath legume canopies? Does the presence of legume scrubs change the soil pools of labile N and P? Is N plant uptake different under N-fixer scrubs than under non-N-fixer scrubs? To answer these questions, we sampled soil beneath the canopy of randomly selected individuals of Erica umbellata, Ulex gallii, and Genista tridentata twice during the growing season. Soil samples were analyzed for organic matter, NH4-N, NO3-N, DON, PO4-P, N mineralization and nitrification rates, and soil microbial biomass-N. In addition, we estimated N uptake by plants and the N concentration in green tissue to compare internal N cycles between legume and non-legume scrubs. Nitrification rates, DON (dissolved organic nitrogen), soil NO3 concentration, and N uptake were significantly higher beneath legume canopies. However, soil microbial biomass-N and extractable-P were significantly lower under legumes. Our results showed that the presence of legume scrubs modify the size of N pools and the dominant form of available N for plants, increasing spatial heterogeneity in mixed stands.
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Simon, Helge, Tim Sinsel, and Michael Bruse. "Introduction of Fractal-Based Tree Digitalization and Accurate In-Canopy Radiation Transfer Modelling to the Microclimate Model ENVI-met." Forests 11, no. 8 (August 10, 2020): 869. http://dx.doi.org/10.3390/f11080869.
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While complex urban morphologies including different materials, wall structures, etc., are rather adequately represented in microclimate models, replication of actual plant geometry is—so far—rather crudely handled. However, plant geometry greatly differs within species and locations while strongly determining a plant’s microclimate performance. To improve the plants representation in numerical models, a new method to describe plant skeletons using the so-called Lindenmayer-System has been implemented in the microclimate model ENVI-met. The new model allows describing much more realistic plants including the position and alignment of leaf clusters, a hierarchical description of the branching system and the calculation of the plant’s biomechanics. Additionally, a new canopy radiation transfer module is introduced that allows not only the simulation of diffuse radiation extinction but also secondary sources of diffuse radiation due to scattering of direct radiation within plant canopies. Intercomparisons between model runs with and without the advancements showed large differences for various plant parameters due to the introduction of the Lindenmayer-System and the advanced radiation scheme. The combination of the two developments represents a sophisticated approach to accurately digitize plants, model radiative transfer in crown canopies, and thus achieve more realistic microclimate results.
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Tontini, Jalise Fabíola, Cesar Henrique Espírito Candal Poli, Viviane da Silva Hampel, Mariana de Souza Farias, Neuza Maria Fajardo, Joseane Anjos da Silva, Luis Henrique Ebling Farinatti, and James Pierre Muir. "Influence of tropical upright pasture structural and chemical characteristics on lamb grazing time." PLOS ONE 16, no. 4 (April 15, 2021): e0242642. http://dx.doi.org/10.1371/journal.pone.0242642.
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Tropical pasture canopy characteristics can alter lamb ingestive behavior. Our study evaluated the ingestive behavior of young lambs in different tropical pastures to identify which variables interfere in their grazing activity. Two years of study were carried out with 54 weaned lambs distributed in three different pasture canopies: 1) monoculture of an upright grass, guinea grass (Panicum maximum; GG); 2) monoculture of a shrubby legume pigeon pea (Cajanus cajan; PP) and 3) contiguous paddock with half GG and half PP (GP). The experiment was set out in a randomized complete block design (3 blocks). Lamb ingestive behavior was observed from sunrise to sunset with records every 5 minutes. To identify the main variables that affected lamb grazing activity, a multivariate analysis of the Decision Tree was performed. Our results showed that there was no difference in the ingestive behavior parameters of young lambs in different canopies (P > 0.05). There was interaction among the canopies and the experimental periods for the variables idleness time and biting rate (P ≤ 0.05). Lambs in all canopies showed more idleness time in the first evaluation period. Lambs in canopies containing grass (GG and GP) exhibited greater bites per minute throughout the experimental period. Lamb grazing time increased 40% as experimental period progressed and plants matured. The Decision Tree identified leaf:stem ratio as the variable that most influenced lamb grazing time in GG and GP canopies while in the PP, grazing time was directly related to canopy height. The behavior of young lambs on tropical pasture is variable as there is a change in the behavioral response to canopy characteristics over time. In addition, the grazing time of these animals can be estimated by means of variables related to canopy structural characteristics (leaf:stem ratio and height) together with chemical variables.
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Wien, H. Chris. "(78) Sheltering Cut Flower Plants to Increase Stem Length." HortScience 41, no. 4 (July 2006): 1066B—1066. http://dx.doi.org/10.21273/hortsci.41.4.1066b.
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The stems of many flower species used as cut flowers are too short to be commercially useful. Non-chemical techniques are needed to increase the length of the harvested stems without weakening stem strength. Field experiments were conducted that explored the use of black or red shade fabric, used either as a canopy, or as a side curtain, with three species of cut flowers. Trachelium caerulum, Eustoma grandiflorum (Echo Champagne), and Rudbeckia hirta (Prairie Sun) were grown in split-plot experiments in which shade and shelter treatments were applied as main plots, and the flower species formed the subplots. In 2004, shade canopies of 70% light transmission were compared in black and red (“ChromatiNet”) netting, and 50% red netting. Stem length increased from 51 cm for unshaded controls to 54, 56, and 59 cm for 70% black, red, and 50% red, respectively. Productivity of the plants was decreased an average of 21% by shading. In 2005, shade canopies of 50% black or red were compared to side curtains of the same materials, and an unsheltered control, growing the same species of flowers. Stem length was increased by 25% when plants were grown under a shade canopy, and by 14% in the side curtain plots. Shading treatments reduced stem yield by 31%, whereas side curtains had no significant effect on number of stems per plant. Color of the netting did not affect stem length or stem yield in 2005. In both years, the thickness of harvested stems were increased significantly in the shelter treatments. The three species reacted similarly to the treatments imposed in both years. Shelter treatments can be a practical way of increasing cut flower stem length.
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Shropshire, Christy, Robert G. Wagner, F. Wayne Bell, and Clarence J. Swanton. "Light attenuation by early successional plants of the boreal forest." Canadian Journal of Forest Research 31, no. 5 (May 1, 2001): 812–23. http://dx.doi.org/10.1139/x01-006.
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The influence of eight early successional plant species from the boreal forest on photosynthetically active radiation (PAR) were compared using a controlled plant competition study. Four woody (green alder, Alnus crispa (Ait.) Pursh; upland willow, Salix humilis Marsh.; white birch, Betula papyrifera Marsh.; wild red raspberry, Rubus idaeus L.) and four herbaceous (eastern bracken fern, Pteridium aquilinum L.; bluejoint grass, Calamagrostis canadensis Michx.; large-leaved aster, Aster macrophyllus L.; fireweed, Epilobium angustifolium L.) plant species were studied using an additive density experiment with jack pine (Pinus banksiana Lamb.) seedlings. The transmission of PAR through the plant canopies was measured using a line quantum sensor under six plant density treatments at the time of maximum canopy development each year. Four measures of plant abundance (planting density, actual density, projected leaf area index, and crown cover) were evaluated for their ability to predict PAR transmission through the plant canopies. Visual estimates of crown cover provided the best models each year. Vertical profiles of PAR transmission were used to compare the canopy structure among plant species and were used to refine the models. During the second growing season, increasing crown cover of bluejoint grass and large-leaved aster had the largest influence on PAR. In the third season, green alder, upland willow, and white birch (along with bluejoint grass and fireweed at the jack pine crown level) had the greatest influence on PAR. PAR measurements taken from a nearby forest for several of the plant species indicate that the models developed from our controlled experiment are reasonably applicable to naturally occurring plant populations.
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Gloser, J. "Schieving, F.: Plato's Plant. On the Mathematical Structure of Simple Plants and Canopies." Biologia plantarum 43, no. 1 (March 1, 2000): 24. http://dx.doi.org/10.1023/a:1026592005693.
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Asner, Gregory P. "Plato's Plant: On the Mathematical Structure of Simple Plants and Canopies. Feike Schieving." Quarterly Review of Biology 75, no. 2 (June 2000): 187–88. http://dx.doi.org/10.1086/393418.
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Burri, Katrin, Christof Gromke, Michael Lehning, and Frank Graf. "Aeolian sediment transport over vegetation canopies: A wind tunnel study with live plants." Aeolian Research 3, no. 2 (November 2011): 205–13. http://dx.doi.org/10.1016/j.aeolia.2011.01.003.
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Wright, Ian J., Michelle R. Leishman, Cassia Read, and Mark Westoby. "Gradients of light availability and leaf traits with leaf age and canopy position in 28 Australian shrubs and trees." Functional Plant Biology 33, no. 5 (2006): 407. http://dx.doi.org/10.1071/fp05319.
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Light availability generally decreases vertically downwards through plant canopies. According to optimisation theory, in order to maximise canopy photosynthesis plants should allocate leaf nitrogen per area (Narea) in parallel with vertical light gradients, and leaf mass per area (LMA) and leaf angles should decrease down through the canopy also. Many species show trends consistent with these predictions, although these are never as steep as predicted. Most studies of canopy gradients in leaf traits have concerned tall herbaceous vegetation or forest trees. But do evergreen species from open habitats also show these patterns? We quantified gradients of light availability, LMA, leaf N and phosphorus (P), and leaf angle along leaf age sequences and vertical canopy profiles, across 28 woody species from open habitats in eastern Australia. The observed trends in LMA, Narea and leaf angle largely conflicted with expectations from canopy optimisation models, whereas trends in leaf P were more consistent with optimal allocation. These discrepancies most likely relate to these species having rather open canopies with quite shallow light gradients, but also suggest that modelling the co-optimisation of resources other than nitrogen is required for understanding plant canopies.
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Hesp, Patrick A. "A review of biological and geomorphological processes involved in the initiation and development of incipient foredunes." Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 96 (1989): 181–201. http://dx.doi.org/10.1017/s0269727000010927.
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SynopsisThe evolution, ecological processes, aerodynamics, and morphology of incipient or new foredunes on the upper beach is reviewed. Four types of incipient foredunes may be distinguished, namely: type 1, those initiated by shadow dune formation within zones of discrete individual pioneer annuals (e.g. Cakile spp.), and perennials (e.g. Spinifex spp.; Ammophila spp.); type 2, those initiated by dunelet or hummock formation within discrete colonies of perennial grasses and herbs; type 3, those initiated by sand deposition within laterally extensive colonies of pioneer seedlings; and type 4, those initiated by sand deposition within a laterally extensive plant rhizome cover.Type 1 dunes are dominated by high, local flow deceleration and 3-D flow separation. Shadow dunes form within and downwind of the discrete plants. If colonised by annual plants, invasion by perennial plants is necessary for survival. Later lateral plant spread and accretion produces hummocky terraces and ridges. Type 2 dunes (dunelets) are characterised by local landward flow deceleration and marginal high velocity side flows. Sand deposition results in the formation of low, discrete, semi-circular convex mounds (seedlings), or more elongate hummocks and mounds (rhizomes). Types 3 and 4 dunes are characterised by laterally extensive, often homogeneous vegetation canopies. High canopies display more rapid landward flow deceleration than low canopies, thus narrow, asymmetric ridges and longer convex ridges result respectively. High plant densities result in rapid down-canopy flow deceleration, maximum traction load retardation and the formation of narrow asymmetric ridges. Dune height decreases and dune length increases as plant densities decrease. Maximum deposition zones occur for each wind velocity range. Whether ramp, terrace or ridge morphologies are formed depends on mode of beach colonisation, plant density and distribution, sand volume, wind speed, and plant species type and morphology.A range of variables which affect foredune morphology and evolution, including plant canopy density, height and distribution, wind velocity, and various ecological environmental processes are examined.
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Gravena, Renan, Ricardo Victoria Filho, Pedro Luis C. A. Alves, Paulo Mazzafera, and Adriana R. Gravena. "Glyphosate has low toxicity to citrus plants growing in the field." Canadian Journal of Plant Science 92, no. 1 (January 2012): 119–27. http://dx.doi.org/10.4141/cjps2011-055.
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Gravena, R., Filho, R. V., Alves, P. L. C. A., Mazzafera, P. and Gravena, A. R. 2012. Glyphosate has low toxicity to citrus plants growing in the field. Can. J. Plant Sci. 92: 119–127. There has been controversy over whether glyphosate used for weed management in citrus fields causes significant toxicity to citrus plants. Glyphosate may be toxic to non-target plants exposed to accidental application or drift. This work evaluated glyphosate toxicity in plants of Valencia citrus (Citrus sinensis L. Osbeck) grafted onto ‘Rangpur lime’ (Citrus limonia L. Osbeck) and citrumelo ‘Swingle’ (Poncirus trifoliata (L.) Raf×Citrus paradisi Macf) by trunk- or foliar-directed herbicide applications under field conditions. In the first experiment, glyphosate was sprayed at rates of 0, 90, 180, 260, 540, 1080 and 2160 g a.e. ha−1 directly on the trunk to a height of 5 cm above the grafting region. In the second experiment, glyphosate was sprayed on the plant canopies at rates of 0, 0.036, 0.36, 3.6, 36, 360 and 720 g a.e. ha−1. There was no visual damage caused by glyphosate applied directly to the trunk, but the plants were affected by glyphosate sprayed directly on the canopies at rates over 360 g a.e. ha−1. The main symptom was observed in the new shoots formed after the application, indicating an effect on meristems. Little or no effect was observed in mature leaves. Eight days after application the levels of shikimate, total free amino acids and total phenolic compounds were unaffected. All plants affected by glyphosate recovered between 6 and 12 mo after the treatments. Therefore, despite some transient symptoms Valencia citrus grafted onto ‘Rangpur lime’ and citrumelo ‘Swingle’ were tolerant to glyphosate.
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Yamaguchi, Hiromu, Daisuke Yasutake, Tomoyoshi Hirota, and Koichi Nomura. "Nondestructive Measurement Method of Leaf Area Index Using Near-infrared Radiation and Photosynthetically Active Radiation Transmitted through a Leafy Vegetable Canopy." HortScience 58, no. 1 (January 2023): 16–22. http://dx.doi.org/10.21273/hortsci16761-22.
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Because the leaf area index (LAI) is an essential parameter for understanding the structure and growth status of plant canopies, nondestructive and continuous estimation methods have been required. Recently, an LAI estimation method using the ratio of near-infrared radiation (NIR; 700–1000 nm) to photosynthetically active radiation (PAR; 400–700 nm) (NIRin/PARin) transmitted through a canopy has been proposed. However, because previous studies on this NIRin/PARin-based LAI estimation method are limited to tall plants (e.g., forest and rice canopies), in this study, we applied this method to a short canopy (i.e., spinach) and investigated its validity. NIRin/PARin and three other traditional indices for indirect LAI estimation—relative PPF density (rPPFD), normalized difference vegetation index (NDVI), and simple ratio (SR)—were measured in 25 canopies with different LAI. NIRin/PARin showed better estimation sensitivity (R2 = 0.88) to the observed LAI than the other three indices, particularly when LAI was greater than 3 m2·m−2. In addition, the LAI estimated from NIRin/PARin measured at 10-min intervals in the entire growth period could capture an increasing trend in the measured LAI throughout the entire growth stage (mean absolute error = 0.87 m2·m−2). Errors in long-term LAI estimations may be caused by the sensor location and insufficient data due to unsuitable weather conditions for measuring NIRin/PARin. The current study demonstrates the merits and limitations of the NIRin/PARin-based LAI estimation method applied to low height canopies, thereby contributing to its practical use in horticultural crops.
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J. S. BRAR, SOM PAL SINGH, and J. S. BAL. "Physico-chemical properties of guava fruits as influenced by solar radiation penetration in plants canopies." Journal of Agrometeorology 13, no. 1 (June 1, 2011): 50–53. http://dx.doi.org/10.54386/jam.v13i1.1334.
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The study was conducted to observe the solar radiation distribution in different parts of 7- year’s old guava plants and its subsequent effect on fruit quality. The interception of solar radiation decreased markedly with the depth of plant canopy from top to bottom as well as with increase in plant density. More than 3/4th of incoming radiations were found to be intercepted by upper one meter periphery of guava plants irrespective of plant spacing. The fruit quality in terms of size, weight, TSS, vitamin C and overall palatability reduced significantly with the depth of plant canopy and decrease in plant spacing. The upper canopy fruits particularly of widely spaced plants were better than others. Winter season fruits were double in weight and more palatable as compared to rainy season fruits.
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Jonsson, K., C. K. Ong, and J. C. W. Odongo. "INFLUENCE OF SCATTERED NÉRÉ AND KARITÉ TREES ON MICROCLIMATE, SOIL FERTILITY AND MILLET YIELD IN BURKINA FASO." Experimental Agriculture 35, no. 1 (February 1999): 39–53. http://dx.doi.org/10.1017/s0014479799001039.
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Microclimate and soil fertility were measured under and away from the canopies of small and large scattered trees of néré (Parkia biglobosa) and karité (Vitellaria paradoxa) to explain their influence on pearl millet (Pennisetum glaucum). During the rainy season, photosynthetically active radiation under both tree canopies was reduced to 24% of incident radiation but, surprisingly, millet biomass was not significantly different from that in the open. Millet seedlings under the tree canopies experienced only 1–9 h week−1 of supra-optimal temperatures (>40 °C) compared with 27 h week−1 in the open. Reduction in windspeed and soil evaporation was observed under the trees but was unlikely to have a significant influence on millet growth since water was not limiting (rainfall = 920 mm).Exchangeable potassium, percentage carbon and pH were significantly higher and δ13C lower in soil under trees than in the open. Nitrogen levels were not significantly higher than in the open except for large néré trees. Carbon derived from C3 plants, calculated from δ13C, was significantly higher in soils under trees than in the open and is recommended as a good indicator of the influence of trees on soils. These results show that the combined beneficial effects of temperature modifications and soil fertility could exceed the negative effect of tree shade.
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Ding, Jingyi, Samantha K. Travers, and David J. Eldridge. "Grow wider canopies or thicker stems: Variable response of woody plants to increasing dryness." Global Ecology and Biogeography 30, no. 1 (November 13, 2020): 183–95. http://dx.doi.org/10.1111/geb.13212.
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Singh, D., M. Balota, T. G. Isleib, E. Collakova, and G. E. Welbaum. "Suitability of Canopy Temperature Depression, Specific Leaf Area, and SPAD Chlorophyll Reading for Genotypic Comparison of Peanut Grown in a Sub-humid Environment." Peanut Science 41, no. 2 (July 1, 2014): 100–110. http://dx.doi.org/10.3146/ps13-11.1.
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ABSTRACT Peanut (Arachis hypogaea L.) is mostly grown under rainfed production with water deficit being the major limiting factor. Several physiological characteristics have been proposed as surrogates for yield and genotypic selection under water deficit in arid climates, but their suitability for selection under sub-humid rainfed production where water deficit can also occur is not clear. Canopy temperature depression (CTD), specific leaf area (SLA), and SPAD chlorophyll reading of eight virginia-type peanut genotypes were evaluated at three growth stages in field trials involving rainfed and irrigated plants in sub-humid environments in northeastern Virginia-Carolina (VC) region in 2011 and 2012. Significant (p≤0.05) variation in pod yield and all physiological characteristics was observed in response to water regime in both years. Rainfed plants had warmer (CTD 2.2 vs. 3.1 °C) and greener canopies in 2011 but cooler (CTD 3.9 vs. 2.2 °C) and less green canopies in 2012 than the irrigated plants. Compared to irrigated plants, rainfed plants had slightly increased SLA in 2011 (135 vs. 131 cm2 g−1), but decreased SLA in 2012 (133 vs. 144 cm2 g−1). Differences (p≤0.05) among genotypes were observed for pod yield, SLA, and SPAD chlorophyll reading, but not for CTD. Among the physiological characteristics, only SPAD chlorophyll readings were significantly correlated to pod yield in all water regimes and growth stages in 2012, but not in 2011. Based on these results, CTD, SLA, and SPAD chlorophyll reading appear to be unsuited for genotypic selection for yield and water-deficit tolerance for peanut grown in sub-humid environment of the Virginia-Carolina region in part due to unpredictable rainfall amount and distribution. For reproducible field evaluations, additional methods will have to be used such as use of rain exclusion shelters.
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Beeson, Richard C., and Thomas H. Yeager. "Plant Canopy Affects Sprinkler Irrigation Application Efficiency of Container-grown Ornamentals." HortScience 38, no. 7 (December 2003): 1373–77. http://dx.doi.org/10.21273/hortsci.38.7.1373.
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Marketable size plants of sweet viburnum (Viburnum odoratissimum Ker-Gawl.), waxleaf ligustrum (Ligustrum japonicum Thunb.), and azalea (Rhododendron spp. L. `Southern Charm') grown in 11.4-L containers were irrigated with overhead impact sprinklers at container spacings ranging from 0 to 51 cm apart. Water reaching the substrate surface was quantified and the percentage of that applied calculated as percent capture (% capture). Percent capture is defined as the percentage of water falling above the plant within a projected vertical cylinder of a container that reaches the substrate surface. For all species, % capture increased linearly with the decline in adjacent canopy interaction, which results from canopies extending beyond the diameter of a container. Increases in total leaf area or leaf area outside the cylinder of a container, in conjunction with increasing distance between containers, were significantly (P < 0.05) correlated with increases in % capture for ligustrum and viburnum. Increases in % capture partially compensated for decreases in percentage of production area occupied by viburnum containers as distances between containers increased, but not for the other two species. Under commercial conditions, optimal irrigation efficiency would be achieved when plants are grown at the minimum spacing required for commercial quality. This spacing should not extend beyond the point where canopies become isolated.
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Tovar-Sanchez, Efraĺn. "Canopy arthropods community within and among oak species in central Mexico." Current Zoology 55, no. 2 (April 1, 2009): 132–44. http://dx.doi.org/10.1093/czoolo/55.2.132.
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Abstract Quercus rugosa and Q. laurina are species that presents a wide geographical distribution range in temperate forests of Mexico. Oak canopies contain a considerable portion of arthropod diversity and the arthropods fauna fulfill a wide variety of ecological roles. We examined the effect of oak species and seasonal changes on some community structure parameters (diversity, composition, similarity, biomass, rare species, and density of arthropod fauna) of canopy arthropods. In total, 40 oak canopies were fogged during rainy and dry season. A total of 614 identified arthropod morphospecies were recognized belonging to 22 orders associated with tree canopies. A separation of host tree species during both seasons, suggesting a different community structure on host plants species was demonstrated by the principal component analyses (PCA), therefore, differences between oak species results in phenotypes that structure the composition of the arthropod community. Q. laurina registered the highest densities, diversity index and number of rare species in comparison with Q. rugosa. While arthropod biomass showed an inverse pattern. Trees more close to one another (spatial distance) register a more similar canopy arthropod fauna. This study suggests that the trees of Q. laurina could act as a center of biodiversity by the accumulation of arthropod fauna with a considerable number of rare species, which presents wide ecological roles or is involved in critical processes that maintain forest ecosystems.
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Doare´, O., B. Moulia, and E. de Langre. "Effect of Plant Interaction on Wind-Induced Crop Motion." Journal of Biomechanical Engineering 126, no. 2 (April 1, 2004): 146–51. http://dx.doi.org/10.1115/1.1688773.
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Plant motion due to wind affects plant growth, a phenomenon called thigmomorphogenesis. Despite intensive studies of the turbulence over plant canopies, the study of plant motion induced by wind has often been limited to individual trees or cereal plants. Few models of global canopy motions are available. Moreover the numerical analysis of models that are based on individual stems becomes time consuming when dealing with crops. A model of motion within the canopies is proposed here using a wave propagation equation within a homogenized continuous medium, and a forcing function representing turbulent gusts advected over the canopy. This model is derived from a discrete model of a set of plant shoots represented as individual oscillators, including elastic contacts between shoots. Such contacts induce nonlinearities into the wave equation. A new experimental method to measure stem dynamical properties and elastic collision properties is presented with an illustration on alfalfa stems. Results obtained modeling plant motions in an alfalfa crop are presented.
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Ballare, C. L., A. L. Scopel, M. L. Roush, and S. R. Radosevich. "How Plants Find Light in Patchy Canopies. A Comparison between Wild-Type and Phytochrome-B-Deficient Mutant Plants of Cucumber." Functional Ecology 9, no. 6 (December 1995): 859. http://dx.doi.org/10.2307/2389983.
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van Herwaarden, A. F., R. A. Richards, G. D. Farquhar, and J. F. Angus. "'Haying-off', the negative grain yield response of dryland wheat to nitrogen fertiliser III. The influence of water deficit and heat shock." Australian Journal of Agricultural Research 49, no. 7 (1998): 1095. http://dx.doi.org/10.1071/a97041.
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Post-anthesis drought and heat shock have been implicated in previous studies as factors contributing to ‘haying-off’ in wheat, but their relative importance has not been investigated. To separate the effects, wheat plants were grown at 2 levels of nitrogen (N) and then exposed to different levels of post-anthesis water deficit in factorial combination with the presence or absence of heat shock. The growth, yield, leaf carbon exchange, water use, and the contents of protein and soluble carbohydrate were measured and compared with the field results reported in Papers I and II of this series. The experiment consisted of wheat plants (cv. Janz) grown in 1·2-m-long tubes outdoors through winter and spring in Canberra, with either nil or 240 kg N/ha applied. The tubes were supported in a refrigerated box to maintain temperatures representative of those of soil in the field, and arranged to form mini-canopies with a density of 29 plants/m2. After anthesis, half of the plants at both levels of N were watered according to their transpiration demand and the other half at 75% of demand to reduce gradually the store of soil water so that water deficit could be initiated at the same time as heat shock. Fifteen days after anthesis, different temperatures were imposed by moving half of the plants into an adjacent glasshouse where heat shock was imposed by raising the air temperature to maxima of ~35ºC for 3 days, to simulate the pattern of temperatures experienced in the field during a heat wave. During this time, the control plants experienced daily maxima of ~25ºC. Following the heat shock, all plants were placed outside and rewatered to enable the assessment of treatment effects on potential leaf function. Both water deficit and high temperature reduced assimilation. After these measurements were taken, well-watered control plants were irrigated according to transpiration demand and the plants with imposed water deficit were watered at 50% of this amount. Yields increased in response to N at both levels of water status and both levels of temperature. That is, there was no evidence of the haying-off reported in Papers I and II of this series. Two factors are proposed to account for the difference between the field crops and the plants grown in the mini-canopy here. Firstly, the pattern of soil-water use differed from the field studies reported in Paper I, with the high-N plants using more soil water than low-N plants during grain filling. Secondly, the level of water-soluble carbohydrates (WSC) in the tube-grown plants of high-N status was greater than that for plants of low-N status, which was opposite to the pattern for field-grown plants reported in Paper II. In addition, the concentrations of WSC in the tube-grown plants were higher than those in the field-grown plants, apparently because lower spike density allowed better penetration of light into the mini-canopies and led to greater assimilate storage than by the denser field crops. The results confirm the conclusion of Paper I that high temperature is not necessary for haying-off, although it is likely that it would worsen the haying-off caused by post-anthesis drought and low WSC reserves in the field. The absence of the haying-off response in this experiment was mostly because the supply of WSC from the sparse canopy was adequate to ofiset the reduction of assimilation due to water deficit and heat shock. A contributing factor to haying-off in the field may therefore be dense canopies resulting in low levels of WSC
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Paturkar, Abhipray, Gourab Sen Gupta, and Donald Bailey. "Making Use of 3D Models for Plant Physiognomic Analysis: A Review." Remote Sensing 13, no. 11 (June 7, 2021): 2232. http://dx.doi.org/10.3390/rs13112232.
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Use of 3D sensors in plant phenotyping has increased in the last few years. Various image acquisition, 3D representations, 3D model processing and analysis techniques exist to help the researchers. However, a review of approaches, algorithms, and techniques used for 3D plant physiognomic analysis is lacking. In this paper, we investigate the techniques and algorithms used at various stages of processing and analysing 3D models of plants, and identify their current limiting factors. This review will serve potential users as well as new researchers in this field. The focus is on exploring studies monitoring the plant growth of single plants or small scale canopies as opposed to large scale monitoring in the field.
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Houtz, Robert L., Douglas D. Archbold, and Malcolm Royer. "ATMOSPHERIC CO2 ENRICHMENT OF TOMATO AND STRAWBERRY PLANTS UNDER FIELD PRODUCTION CONDITIONS." HortScience 25, no. 9 (September 1990): 1141b—1141. http://dx.doi.org/10.21273/hortsci.25.9.1141b.
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A technique was developed for controlled micro-release of CO2 into the leaf canopy of strawberry and tomato plants under field production conditions; The leaf canopy atmosphere of tomato plants was enriched to 500 and 1200 ppm CO2 with release rates of 60 and 300 l/h·30 m of row respectively. After 60 days of enrichment for 6 h each day beginning at fruit set, the total shoot biomass and yield was increased 41% and 25 % respectively for the high CO2 release rate. Strawberry leaf canopies did not show increased CO levels with CO2 enrichment except under ventilated2 row-covers where the atmospheric CO2 level was increased to 1500 ppm CO2. Although the total biomass was increased 39% this did not translate into increased yields perhaps due to excessive temperatures under the row covers.
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Colomer, Jordi, and Teresa Serra. "The World of Edges in Submerged Vegetated Marine Canopies: From Patch to Canopy Scale." Water 13, no. 17 (September 3, 2021): 2430. http://dx.doi.org/10.3390/w13172430.
Full textAbstract:
This review describes the world of edges in submerged vegetated marine canopies (seagrasses, saltmarshes, and seaweeds) where an edge is a boundary with a frontal area separating the vegetation from the adjacent non-vegetated zones. Plants within the vegetation are made of flexible elements pronating in the direction of the flow and oscillating back and forth in response to wave forcing. Some of them also occupy the full height within the water body. The analysis focuses on both the canopy- and local-patch scales to acquire knowledge about the hydrodynamics and the biophysical interactions in the structural shallows and deep limits of the canopies as well as on the structural edges of vegetation patches and the edges in the gaps within the canopies. The spatial arrangements of both canopy and patch edges are not only well imposed through the modification of hydrodynamics, but so too through small-scale interactions from internal structural causes and modifications. The continuous fragmentation of coastal marine habitats has reduced their structural complexity, thus making habitat edges a prevalent seascape feature, including in the shallow (or upper) and deep (or lower) limits of the canopies, the patch edges, and the edges in the gaps within the canopies. Canopy patches represent a region of high flow resistance where flow deflects and accelerates above and/or next to the canopy, resulting in an increase in water velocity and turbulence, especially at the edges of the patch. At the edges, energy transfer is found in spectral wave velocities from the longer to shorter wave period components. Likewise, at the edges, the net deposition of sediments decreases over a distance to a certain length, relative to the bare bed, which is associated with a region of vertical updraft and elevated turbulent kinetic energy. The edge effects also relate to the influence that a patch edge can have on determining species composition and predation risk, which is additionally mediated by the effect the edges have on habitat complexity within the vegetated patch. Organism feedback within the edges does not simply follow the canopy and local features and, in fact, the intricate interaction between biogeophysical processes is key in explaining the complexity of coastal submerged canopy landscapes. For example, proximity to patch edges has a greater influence on epifaunal density and community structure than structural complexity or predation do. The extent to which edges reduce predation risk depends on the extent to which they support higher structural complexities compared to patch interiors. The canopies’ shallow limits and their position in the underwater beach profile are mostly limited by light availability, the intensity of the wave action, and the local nearshore hydrodynamics, but they also depend on the local structural conditions at the vegetated side. The deep limits of the canopies, however, mainly depend on the availability of light and research findings support migration both to the deeper and shallower layers. All structural edges face changes caused by increasing nutrient inputs, development of coastal zones and the increasing impact of climate change. A considerable challenge to managing, restoring, and conserving coastal marine ecosystems stems from understanding how the canopies are able to cope with these natural and anthropogenic disturbances.
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Klimenko, Dmitry E., Ekaterina S. Cherepanova, and Alena A. Khomyleva. "Spatial Modeling of Maximum Capacity Values of Irrecoverable Rainfall Retention by Forests in a Small Watershed." Forests 11, no. 6 (June 5, 2020): 641. http://dx.doi.org/10.3390/f11060641.
Full textAbstract:
When performing hydrologic calculations, the actual amount of rain precipitation falling under the tree canopies of the taiga zone is one of the most important factors in forming and estimating rainfall runoff. This is due to the fact that only a portion of rainfall reaching the soil through the forest canopy takes part in forming river runoff. At present, there is no unanimity on methods of estimating rainfall retention by the canopies of different tree species in various natural geographical zones. The existing estimation methods rely on empirical observations of net and gross rainfall rather than on the results of physical modeling of moisture on leaf surfaces in droplet form. The disadvantages of the existing methods mean that it is not possible to make a spatial estimation of rainfall captured by canopies. The purpose of this study was to map the maximum rainfall interception capacity for a small forest watershed. The authors were able to solve the following problems: (1) In situ modeling of specific water retention in droplet form on leaf surfaces of tree species of the experimental watershed in the middle taiga subzone was carried out and the specific water retention per unit leaf area was determined. Such experiments have never been conducted previously. (2) Indirect methods of estimating the leaf surface area of tree plants depending on the amount of phytomass, age and height of tree stands were developed. (3) Mapping of tree stand characteristics (such as species composition, height, canopy cover) were performed, and together with the specific rainfall interception capacity, which was determined during experiments, provided the basis for a map of maximum rainfall retention capacity by canopies, i.e., a spatial image of irrecoverable rainfall losses was obtained. Rainfall is retained on a canopy in droplet form (droplet size varies from 10.6 to 18.6 mg). Specific water retention (mass per unit leaf surface area) is determined by the leaf (needle) roughness. The overall droplet retention on canopies is determined by leaf surface area and precipitation intensity. The maximum mass of the rainfall retained on the canopies of individual deciduous trees reaches 77 kg, (3.0–4.0 mm per canopy projection area) and that of coniferous trees ranges from 24.8 to 58.0 kg (1.9 to 5.9 mm). Understanding rainfall loss values in hydrology is of key importance in distributed models of rainfall flooding. Taking into account rainfall losses due to canopy interception makes it possible to reduce the margin of error in calculations of maximum rainfall flood loss from 126% to 25%.
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Jaskulska, Iwona, and Dariusz Jaskulski. "Winter Wheat and Spring Barley Canopies under Strip-Till One-Pass Technology." Agronomy 11, no. 3 (February 26, 2021): 426. http://dx.doi.org/10.3390/agronomy11030426.
Full textAbstract:
Modern agriculture promotes non-inversion, ploughless tillage systems, and simplified plant cultivation methods. Environmentally friendly plant production technologies must nevertheless guarantee high yields of good quality. In the years 2017/18–2019/20, studies were carried out in which it was assumed that these conditions could be met by strip soil tillage with simultaneous application of fertilisers and paired-row sowing (strip-till one-pass (ST-OP). Two field experiments were conducted to compare two cereal cultivation technologies: ploughless, non-inversion tillage, seedbed preparation, entire-surface fertilisation, and narrowly spaced row sowing (PL-ES); and ST-OP, with two narrow spaced rows (12 cm apart) in a strip of tilled (paired-row sowing), fertilised soil, and a 24.4-cm-wide inter-row of untilled soil. Fields of winter wheat and spring barley were investigated, assessing plant density and spatial variation, plant height, yield components, and yield. The morphological and physiological indices of the plants and canopies determined were leaf area index (LAI), photosynthetically active radiation (PAR), leaf stomatal conductance, and relative chlorophyll content in leaves. The ST-OP technology provides uniform planting in the canopy, especially under conditions of insufficient rainfall. Fields of winter wheat and spring barley cultivated by this method featured shorter plants with more stalks with spikes, and spikes with greater weight and number of grains, than in the fields of cereals grown under PL-ES. The LAI and PAR indices in the narrow inter-rows were similar to the PL-ES technology and higher than in the wide, untilled inter-rows. Leaves of cereals grown under ST-OP contained more chlorophyll and had a higher leaf stomatal conductance. This technology, which provides higher winter wheat and spring barley yields, is an alternative to ploughless tillage with row sowing.
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Łukasik, Adam, Marzena Rachwał, and Zygmunt Strzyszcz. "Application Of Magnetic Susceptibility of Soils for Identification of Potential Sources of Secondary Dust Emmision in Urban Parks." Soil Science Annual 63, no. 4 (December 1, 2012): 34–40. http://dx.doi.org/10.2478/v10239-012-0039-7.
Full textAbstract:
Abstract Urban forests and parks, besides a recreation function, play significant role in pollution removal by tree canopies. Main sources of dust emissions in cities are industry (steelworks, power plants, coking plants, cement plants) and traffic. The most of dusts, stored in tree crowns, are deposited on soil surface as litterfall (leaves, needles) or are washed into soil by stemflow and throughfall. However, certain amount of dusts can be released into atmosphere as secondary dust emission. The presented studies were conducted on areas of four urban parks and both magnetic and chemical analyses of topsoil were employed. Results show topsoil contamination by heavy metals in urban parks and cumulative role of vegetations (trees) in processes of distribution of air pollution into soil surface. Magnetic susceptibility measurements allow for discrimination of areas for being the potential sources of secondary dust emission in urban parks.
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Morales-Salazar, Gonzalo, Bielinski M. Santos, and Jose P. Morales-Payan. "Response of Young `Keitt' Mango Trees to Nitrogen and Gibberellic Acid Supply." HortScience 32, no. 4 (July 1997): 603C—603. http://dx.doi.org/10.21273/hortsci.32.4.603c.
Full textAbstract:
Field experiments were conducted in the Dominican Republic to determine the effect of gibberellic acid (GA) and nitrogen (N) treatments on the growth of lateral branches in young `Keitt' mango plants. Two-year-old `Keitt' mango plants were pruned and treated with combinations of gibberellic acid (0, 20, 40, 60, 80, and 100 ppm) foliar sprays and soil nitrogen fertilization (18.75, 37.50, and 56.25 g). There were no N by GA interactions. Treatments did not significantly influence days to sprouting, number of sprouts, or number of leaves per sprout. N rates did not affect sprout length, whereas increasing GA rates enhanced sprout elongation. The effect of GA was described by the linear equation Y = 14.59 + 0.27X. Results indicate that GA sprays can be used to enhance sprout elongation to promote the desired round shape in canopies of `Keitt' mango plants.
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Warnock, Daniel F., and Rebecca Loughner. "Comparing Three Solutions for Extracting Western Flower Thrips from Coleus Shoots." HortScience 37, no. 5 (August 2002): 787–89. http://dx.doi.org/10.21273/hortsci.37.5.787.
Full textAbstract:
Western flower thrips [Frankliniella occidentalis (Pergande)] are small-bodied insects that prefer tight spaces such as flower buds and young leaves. Western flower thrips (WFT) pose sampling problems when compared with larger insects commonly found in plant canopies. Techniques to wash insects from plant canopies exist; however, plant type, plant age, and spatial distribution of insects within the canopy impact the efficacy of sampling. An experiment was designed to determine if 75% ethyl alcohol (EtOH), 0.1% detergent solution, or deionized water effectively wash WFT from the foliage of six coleus [Solenostemon scutellarioides (L.) Codd] genotypes inoculated with 32 adults and larvae. The number of WFT recovered after filtration through three mesh sizes varied between blocks and extraction solutions. The mean number of thrips recovered from coleus shoots with 75% EtOH solution, 0.1% detergent solution, or deionized water was 6.7, 8.4, or 0.8, respectively. The number of thrips recovered did not vary by coleus genotype, indicating the extraction solutions were equally effective on smooth leaf or curly leaf type plants. The 75% EtOH extraction solution is recommended for subsequent experiments.