scholarly journals The effect of vapor pressure deficit on water use efficiency at the subdaily time scale

2014 ◽  
Vol 41 (14) ◽  
pp. 5005-5013 ◽  
Author(s):  
Sha Zhou ◽  
Bofu Yu ◽  
Yuefei Huang ◽  
Guangqian Wang
Keyword(s):  
Vapor Pressure ◽  
Water Use Efficiency ◽  
Water Use ◽  
Time Scale ◽  
Vapor Pressure Deficit ◽  
Use Efficiency

scholarly journals Protected Fresh Grapefruit Cultivation Systems: Antipsyllid Screen Effects on Plant Growth and Leaf Transpiration, Vapor Pressure Deficit, and Nutrition

2017 ◽  
Vol 27 (5) ◽  
pp. 666-674 ◽  
Author(s):  
Rhuanito S. Ferrarezi ◽  
Alan L. Wright ◽  
Brian J. Boman ◽  
Arnold W. Schumann ◽  
Fred G. Gmitter ◽  
...  
Keyword(s):  
Plant Growth ◽  
Vapor Pressure ◽  
Water Use Efficiency ◽  
Surface Area ◽  
Water Use ◽  
Vapor Pressure Deficit ◽  
Nitrogen Concentration ◽  
Area Index ◽  
Young Tree ◽  
Use Efficiency

Completely enclosed screen houses can physically exclude contact between the asian citrus psyllid [ACP (Diaphorina citri)] and young, healthy citrus (Citrus sp.) trees and prevent huanglongbing (HLB) disease development. The current study investigated the use of antipsyllid screen houses on plant growth and physiological parameters of young ‘Ray Ruby’ grapefruit (Citrus ×paradisi) trees. We tested two coverings [enclosed screen house and open-air (control)] and two planting systems (in-ground and container-grown), with four replications arranged in a split-plot experimental design. Trees grown inside screen houses developed larger canopy surface area, canopy surface area water use efficiency (CWUE), leaf area index (LAI) and LAI water use efficiency (LAIWUE) relative to trees grown in open-air plots (P < 0.01). Leaf water transpiration increased and leaf vapor pressure deficit (VPD) decreased in trees grown inside screen houses compared with trees grown in the open-air plots. CWUE was negatively related to leaf VPD (P < 0.01). Monthly leaf nitrogen concentration was consistently greater in container-grown trees in the open-air compared with trees grown in-ground and inside the screen houses. However, trees grown in-ground and inside the screen houses did not experience any severe leaf N deficiencies and were the largest trees, presenting the highest canopy surface area and LAI at the end of the study. The screen houses described here provided a better growing environment for in-ground grapefruit because the protective structures accelerated young tree growth compared with open-air plantings while protecting trees from HLB infection.

scholarly journals Divergent gas-exchange and chlorophyll fluorescence in F1 hybrids driving habitat differentiation compared to their parents in Buddleja

2019 ◽  
Author(s):  
Weichang Gong ◽  
Yaqing Chen ◽  
Jian Wang ◽  
Han Yuan
Keyword(s):  
Chlorophyll Fluorescence ◽  
Gas Exchange ◽  
Vapor Pressure ◽  
Water Use Efficiency ◽  
Growth Performance ◽  
Water Use ◽  
Vapor Pressure Deficit ◽  
F1 Hybrids ◽  
Photochemical Quenching ◽  
Use Efficiency

Abstract Background Inter-specific hybridizations were common and can easily take place in Buddleja , and it was an important way for evolution and rapid speciation. The F1 hybrid in this study was a newly identified inter-specific hybridization between B. crispa and B. offic inalis in Sino-Himalayan region. In the natural hybrid zones, F1 hybrids always occupy different habitats from their parents. The objective of this study was to explore environmental acclimatization of F1 hybrids and their parents at physiological and biochemical levels.Results The results showed that F1 hybrids performed as an intermediate in adaptation to their parents, with divergent gas-exchange and chlorophyll fluorescence features. F1 hybrids showed the parallel light compensation point and light saturation point with their parents, but low utilization efficiency to low-light density. They synthesized the greatest total chlorophyll content (10.41 ± 0.56 mg•g -1 ) in leaves than their parents. During the diurnal variation of photosynthesis, F1 hybrids markedly decreased and preserved the stomatal conductance and leaf transpiration rate at a low level. However, they kept high carbon assimilation rate and water-use efficiency with markedly increased vapor pressure deficit. In F1 hybrids, the maximum net photosynthetic rate, maximum water-use efficiency and maximum vapor pressure deficit were 10.48 ± 0.50 mmol CO 2 •mmol -1 photo, 21.52 ± 2.20 µmol•mmol -1 and 4.18 ± 0.55 kPa, respectively. In addition, all Buddleja species performed well and grow healthy with high level of the maximum photochemical efficiency of PSII and low non-photochemical quenching, 0.83 ± 0.004 - 0.85 ± 0.004, and 1.22 ± 0.15 - 1.97 ± 0.08, respectively. In F1 hybrids, they showed great photochemical activity compared to their parental species with high photochemical quenching. Furthermore, the effective quantum yield and electron transport rate presented a similar behavior.Conclusions The results indicated that F1 hybrids have great photochemical activities and growth acclimatization compared to their parents. Associated with the growth performance of F1 hybrids in the homogenous garden, our results suggested that the divergent gas-exchange and chlorophyll fluorescence patterns may facilitate F1 hybrids to respond to different habitats, and to improve growth performance.

scholarly journals Consistent Differences in Field Leaf Water-Use Efficiency among Soybean Cultivars

Plants ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 123 ◽  
Author(s):  
James Bunce
Keyword(s):  
Water Use Efficiency ◽  
Carbon Isotope ◽  
Water Use ◽  
Vapor Pressure Deficit ◽  
Cultivar Differences ◽  
Stomatal Response ◽  
Soybean Cultivars ◽  
Air Temperatures ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

High intrinsic water-use efficiency (WUEi), the ratio of leaf photosynthesis to stomatal conductance, may be a useful trait in adapting crops to water-limited environments. In soybean, cultivar differences in stomatal response to vapor pressure deficit have not consistently translated into differences in WUEi in the field. In this study, six cultivars of soybeans previously shown to differ in WUEi in indoor experiments were grown in the field in Beltsville, Maryland, and tested for mid-day WUEi on nine clear days during the mid-seasons of two years. Measurement dates were chosen for diverse temperatures, and air temperatures ranged from 21 to 34 °C on the different dates. Air saturation deficits for water vapor ranged from 0.9 to 2.2 kPa. Corrected carbon isotope delta values for 13C (CID) were determined on mature, upper canopy leaves harvested during early pod filling each year. WUEi differed among cultivars in both years and the differences were consistent across measurement dates. Correlations between mean WUEi and CID were not significant in either year. It is concluded that consistent cultivar differences in WUEi exist in these soybean cultivars under field conditions, but that carbon isotope ratios may not be useful in identifying them because of cultivar differences in mesophyll conductance.

scholarly journals The importance of radiation for semi-empirical water-use efficiency models

2017 ◽  
Author(s):  
Sven Boese ◽  
Martin Jung ◽  
Nuno Carvalhais ◽  
Markus Reichstein
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Vapor Pressure Deficit ◽  
Global Radiation ◽  
Model Performance ◽  
Fundamental Property ◽  
Improve Model ◽  
Model Predictions ◽  
Use Efficiency ◽  
Semi Empirical

Abstract. Water-use efficiency (WUE) is a fundamental property for the coupling of carbon and water cycles in plants and ecosystems. Existing model formulations predicting this variable differ in the type of response of WUE to the atmospheric vapor pressure deficit of water (VPD). We tested a representative WUE model on ecosystem scale at 110 eddy-covariance sites of the FLUXNET initiative by predicting evapotranspiration (ET) based on gross primary productivity (GPP) and VPD. We found that introducing an intercept term in the formulation increases model performance considerably, indicating that an additional factor needs to be considered. We demonstrate that this intercept term varies seasonally and we subsequently associate it with radiation. Replacing the constant intercept term with a linear function of global radiation was found to further improve model predictions of ET. Our new semi-empirical ecosystem WUE formulation indicates that, averaged over all sites, this radiation term accounts for up to half (40–49 %) of transpiration. These empirical findings challenge the current understanding of water-use efficiency on ecosystem-scale.

scholarly journals The importance of radiation for semiempirical water-use efficiency models

2017 ◽  
Vol 14 (12) ◽  
pp. 3015-3026 ◽  
Author(s):  
Sven Boese ◽  
Martin Jung ◽  
Nuno Carvalhais ◽  
Markus Reichstein
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Primary Productivity ◽  
Vapor Pressure Deficit ◽  
Global Radiation ◽  
Model Performance ◽  
Fundamental Property ◽  
Improve Model ◽  
Model Predictions ◽  
Use Efficiency

Abstract. Water-use efficiency (WUE) is a fundamental property for the coupling of carbon and water cycles in plants and ecosystems. Existing model formulations predicting this variable differ in the type of response of WUE to the atmospheric vapor pressure deficit of water (VPD). We tested a representative WUE model on the ecosystem scale at 110 eddy covariance sites of the FLUXNET initiative by predicting evapotranspiration (ET) based on gross primary productivity (GPP) and VPD. We found that introducing an intercept term in the formulation increases model performance considerably, indicating that an additional factor needs to be considered. We demonstrate that this intercept term varies seasonally and we subsequently associate it with radiation. Replacing the constant intercept term with a linear function of global radiation was found to further improve model predictions of ET. Our new semiempirical ecosystem WUE formulation indicates that, averaged over all sites, this radiation term accounts for up to half (39–47 %) of transpiration. These empirical findings challenge the current understanding of water-use efficiency on the ecosystem scale.

scholarly journals When does vapor pressure deficit drive or reduce evapotranspiration?

2018 ◽  
Author(s):  
Adam Massmann ◽  
Pierre Gentine ◽  
Changjie Lin
Keyword(s):  
Vapor Pressure ◽  
Water Use ◽  
Environmental Conditions ◽  
Water Conservation ◽  
Physiological Response ◽  
Vapor Pressure Deficit ◽  
Use Efficiency ◽  
Semi Empirical ◽  
Enriched Co2

Abstract. Increasing vapor pressure deficit (VPD) increases atmospheric demand for water, and vapor pressure deficit is expected to rise with increasing greenhouse gases. While increased evapotranspiration (ET) in response to increased atmospheric demand seems intuitive, plants are capable of reducing ET in response to increased VPD by closing their stomata, in an effort to conserve water. Here we examine which effect dominates response to increasing VPD: atmospheric demand and increases in ET, or plant physiological response (stomata closure) and decreases in ET. We use Penman-Monteith, combined with semi-empirical optimal stomatal regulation theory and underlying water use efficiency, to develop a theoretical framework for understanding how ET responds to increases in VPD. The theory suggests that for most environmental conditions and plant types, plant physiological response dominates and ET decreases with increasing VPD. Plants that are evolved or bred to prioritize primary production over water conservation (e.g. crops) exhibit a higher likelihood of atmospheric demand-driven response (ET increasing). However for forest, grass, savannah, and shrub plant types, ET more frequently decreases than increases with rising VPD. This work serves as an example of the utility of our simplified framework for disentangling land-atmosphere feedbacks, including the characterization of ET response in an atmospherically drier, enriched CO2 world.

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