The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Amilcare Porporato - One of the best experts on this subject based on the ideXlab platform.
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plants in Water controlled ecosystems active role in hydrologic processes and response to Water Stress iii vegetation Water Stress
Advances in Water Resources, 2001Co-Authors: Francesco Laio, Luca Ridolfi, Amilcare Porporato, Ignacio RodrigueziturbeAbstract:The reduction of soil moisture content during droughts lowers the plant Water potential and decreases transpiration; this in turn causes a reduction of cell turgor and relative Water content which brings about a sequence of damages of increasing seriousness. A review of the literature on plant physiology and Water Stress shows that vegetation Water Stress can be assumed to start at the soil moisture level corresponding to incipient stomatal closure and reach a maximum intensity at the wilting point. The mean crossing properties of these soil moisture levels crucial for Water Stress are derived analytically for the stochastic model of soil moisture dynamics described in Part II (F. Laio, A. Porporato, L. Ridolfi, I. Rodriguez-Iturbe. Adv. Water Res. 24 (7) (2001) 707-723). These properties are then used to propose a measure of vegetation Water Stress which combines the mean intensity, duration, and frequency of periods of soil Water deficit. The characteristics of vegetation Water Stress are then studied under different climatic conditions, showing how the interplay between plant, soil, and environment can lead to optimal conditions for vegetation.
Francesco Laio - One of the best experts on this subject based on the ideXlab platform.
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A stochastic model for vegetation Water Stress.
Ecohydrology, 2010Co-Authors: Fabio Borgogno, Paolo D'odorico, Francesco Laio, Luca RidolfiAbstract:Soil Water limitations cause Water-Stressed conditions in vegetation because of temporary and/or permanent damage to plant tissues. Vegetation Water Stress is here assumed to increase when soil moisture is below a threshold level, s*, and to decrease otherwise. The crossing properties of s* allow one to describe the temporal evolution of Water Stress, Φ, as a dichotomic Markov process. The available analytical solutions for dichotomic processes are used to determine the probability density function of Φ and the mean first-passage times (MFPT) of a Water Stress threshold. MFTP is used as a measure of the variability of Water Stress. The use of MFPT in conjunction with the average Stress levels allows us to provide a more complete characterization of health/Stress conditions in vegetation. We investigate the influence on the dynamics of vegetation Water Stress of different climatic, pedological, and plant physiological parameters. From these analyses, we find, for example, that resistant species are favoured in relatively humid environments, whereas resilient shallow-rooted plants have an advantage in drier conditions.
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plants in Water controlled ecosystems active role in hydrologic processes and response to Water Stress iii vegetation Water Stress
Advances in Water Resources, 2001Co-Authors: Francesco Laio, Luca Ridolfi, Amilcare Porporato, Ignacio RodrigueziturbeAbstract:The reduction of soil moisture content during droughts lowers the plant Water potential and decreases transpiration; this in turn causes a reduction of cell turgor and relative Water content which brings about a sequence of damages of increasing seriousness. A review of the literature on plant physiology and Water Stress shows that vegetation Water Stress can be assumed to start at the soil moisture level corresponding to incipient stomatal closure and reach a maximum intensity at the wilting point. The mean crossing properties of these soil moisture levels crucial for Water Stress are derived analytically for the stochastic model of soil moisture dynamics described in Part II (F. Laio, A. Porporato, L. Ridolfi, I. Rodriguez-Iturbe. Adv. Water Res. 24 (7) (2001) 707-723). These properties are then used to propose a measure of vegetation Water Stress which combines the mean intensity, duration, and frequency of periods of soil Water deficit. The characteristics of vegetation Water Stress are then studied under different climatic conditions, showing how the interplay between plant, soil, and environment can lead to optimal conditions for vegetation.
Ignacio Rodrigueziturbe - One of the best experts on this subject based on the ideXlab platform.
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plants in Water controlled ecosystems active role in hydrologic processes and response to Water Stress iii vegetation Water Stress
Advances in Water Resources, 2001Co-Authors: Francesco Laio, Luca Ridolfi, Amilcare Porporato, Ignacio RodrigueziturbeAbstract:The reduction of soil moisture content during droughts lowers the plant Water potential and decreases transpiration; this in turn causes a reduction of cell turgor and relative Water content which brings about a sequence of damages of increasing seriousness. A review of the literature on plant physiology and Water Stress shows that vegetation Water Stress can be assumed to start at the soil moisture level corresponding to incipient stomatal closure and reach a maximum intensity at the wilting point. The mean crossing properties of these soil moisture levels crucial for Water Stress are derived analytically for the stochastic model of soil moisture dynamics described in Part II (F. Laio, A. Porporato, L. Ridolfi, I. Rodriguez-Iturbe. Adv. Water Res. 24 (7) (2001) 707-723). These properties are then used to propose a measure of vegetation Water Stress which combines the mean intensity, duration, and frequency of periods of soil Water deficit. The characteristics of vegetation Water Stress are then studied under different climatic conditions, showing how the interplay between plant, soil, and environment can lead to optimal conditions for vegetation.
Luca Ridolfi - One of the best experts on this subject based on the ideXlab platform.
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A stochastic model for vegetation Water Stress.
Ecohydrology, 2010Co-Authors: Fabio Borgogno, Paolo D'odorico, Francesco Laio, Luca RidolfiAbstract:Soil Water limitations cause Water-Stressed conditions in vegetation because of temporary and/or permanent damage to plant tissues. Vegetation Water Stress is here assumed to increase when soil moisture is below a threshold level, s*, and to decrease otherwise. The crossing properties of s* allow one to describe the temporal evolution of Water Stress, Φ, as a dichotomic Markov process. The available analytical solutions for dichotomic processes are used to determine the probability density function of Φ and the mean first-passage times (MFPT) of a Water Stress threshold. MFTP is used as a measure of the variability of Water Stress. The use of MFPT in conjunction with the average Stress levels allows us to provide a more complete characterization of health/Stress conditions in vegetation. We investigate the influence on the dynamics of vegetation Water Stress of different climatic, pedological, and plant physiological parameters. From these analyses, we find, for example, that resistant species are favoured in relatively humid environments, whereas resilient shallow-rooted plants have an advantage in drier conditions.
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plants in Water controlled ecosystems active role in hydrologic processes and response to Water Stress iii vegetation Water Stress
Advances in Water Resources, 2001Co-Authors: Francesco Laio, Luca Ridolfi, Amilcare Porporato, Ignacio RodrigueziturbeAbstract:The reduction of soil moisture content during droughts lowers the plant Water potential and decreases transpiration; this in turn causes a reduction of cell turgor and relative Water content which brings about a sequence of damages of increasing seriousness. A review of the literature on plant physiology and Water Stress shows that vegetation Water Stress can be assumed to start at the soil moisture level corresponding to incipient stomatal closure and reach a maximum intensity at the wilting point. The mean crossing properties of these soil moisture levels crucial for Water Stress are derived analytically for the stochastic model of soil moisture dynamics described in Part II (F. Laio, A. Porporato, L. Ridolfi, I. Rodriguez-Iturbe. Adv. Water Res. 24 (7) (2001) 707-723). These properties are then used to propose a measure of vegetation Water Stress which combines the mean intensity, duration, and frequency of periods of soil Water deficit. The characteristics of vegetation Water Stress are then studied under different climatic conditions, showing how the interplay between plant, soil, and environment can lead to optimal conditions for vegetation.
Hipólito Medrano - One of the best experts on this subject based on the ideXlab platform.
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The Effects of Water Stress on Plant Respiration
Plant Respiration, 2020Co-Authors: Jaume Flexas, Miquel Ribas-carbo, Jeroni Galmés, Hipólito MedranoAbstract:Plant growth can be limited by several factors, among which a lack of Water is considered of major importance. Despite the vast knowledge of the effect of Water Stress on photosynthesis, there is much less known about its effect on respiration. Respiration, unlike photosynthesis, never halts, and it reflects the overall metabolism. However, the data available on the effect of Water Stress on respiration show large variation, from inhibition to stimulation under different Water-Stress conditions. This chapter combines a review of the latest studies of the effect of Water Stress on plant respiration with the compilation of data from different authors and recent results to develop a working hypothesis to explain how respiration is regulated under Water Stress. Leaf respiration shows a biphasic response to Relative Water Content (RWC), decreasing in the initial stages of Water Stress (RWC > 60%), and increasing as RWC decreases below 50%. Under this hypothesis, the initial decrease in respiration would be related to the immediate inhibition of leaf growth and, consequently, the growth respiration component. The increase of respiration at lower RWC would relate to an increasing metabolism as the plant triggers acclimation mechanisms to resist Water Stress. These mechanisms would increase the maintenance component of respiration, and, as such, the overall respiration rate. This hypothesis aims to give a metabolic explanation for the observed results, and to raise questions that can direct future plant respiration experiments.
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uavs challenge to assess Water Stress for sustainable agriculture
Agricultural Water Management, 2015Co-Authors: Jorge Gago, Jaume Flexas, Cyril Douthe, Rafael E Coopman, P P Gallego, Miquel Ribascarbo, J M Escalona, Hipólito MedranoAbstract:Unmanned aerial vehicles (UAVs) present an exciting opportunity to monitor crop fields with high spatial and temporal resolution remote sensing capable of improving Water Stress management in agriculture. In this study, we reviewed the application of different types of UAVs using different remote sensors and compared their performance with ground-truth plant data. Several reflectance indices, such as NDVI, TCARI/OSAVI and PRInorm obtained from UAVs have shown positive correlations related to Water Stress indicators such as Water potential (Ψ) and stomatal conductance (gs). Nevertheless, they have performed differently in diverse crops; thus, their uses and applications are also discussed in this study. Thermal imagery is also a common remote sensing technology used to assess Water Stress in plants, via thermal indices (calculated using artificial surfaces as references), estimates of the difference between canopy and air temperature, and even canopy conductance estimates derived from leaf energy balance models. These indices have shown a great potential to determine field Stress heterogeneity using unmanned aerial platforms. It has also been proposed that chlorophyll fluorescence could be an even better indicator of plant photosynthesis and Water use efficiency under Water Stress. Therefore, developing systems and methodologies to easily retrieve fluorescence from UAVs should be a priority for the near future. After a decade of work with UAVs, recently emerging technologies have developed more user-friendly aerial platforms, such as the multi-copters, which offer industry, science, and society new opportunities. Their use as high-throughput phenotyping platforms for real field conditions and also for Water Stress management increasing temporal and resolution scales could improve our capacity to determine important crop traits such as yield or Stress tolerance for breeding purposes.
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Effects of Water Stress on respiration in soybean leaves.
Plant Physiology, 2005Co-Authors: Miquel Ribas-carbo, Nicolas L. Taylor, Larry Giles, Sílvia Busquets, Patrick M. Finnegan, Hans Lambers, Hipólito Medrano, Joseph A. Berry, Jaume FlexasAbstract:The effect of Water Stress on respiration and mitochondrial electron transport has been studied in soybean ( Glycine max ) leaves, using the oxygen-isotope-fractionation technique. Treatments with three levels of Water Stress were applied by irrigation to replace 100%, 50%, and 0% of daily Water use by transpiration. The levels of Water Stress were characterized in terms of light-saturated stomatal conductance ( g s ): well irrigated ( g s > 0.2 mol H 2 O m −2 s −1 ), mildly Water Stressed ( g s between 0.1 and 0.2 mol H 2 O m −2 s −1 ), and severely Water Stressed ( g s 2 O m −2 s −1 ). Although net photosynthesis decreased by 40% and 70% under mild and severe Water Stress, respectively, the total respiratory oxygen uptake ( V t ) was not significantly different at any Water-Stress level. However, severe Water Stress caused a significant shift of electrons from the cytochrome to the alternative pathway. The electron partitioning through the alternative pathway increased from 10% to 12% under well-Watered or mild Water-Stress conditions to near 40% under severe Water Stress. Consequently, the calculated rate of mitochondrial ATP synthesis decreased by 32% under severe Water Stress. Unlike many other Stresses, Water Stress did not affect the levels of mitochondrial alternative oxidase protein. This suggests a biochemical regulation (other than protein synthesis) that causes this mitochondrial electron shift.
