Effects of soil moisture on water transport, photosynthetic carbon gain and water use efficiency in tomato are influenced by evaporative demand

2019 ◽  
Vol 226 ◽  
pp. 105818
Author(s):  
Qingming Li ◽  
Min Wei ◽  
Yiman Li ◽  
Gaili Feng ◽  
Yaping Wang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Use Efficiency ◽  
Water Transport ◽  
Water Use ◽  
Carbon Gain ◽  
Evaporative Demand ◽  
Photosynthetic Carbon ◽  
Use Efficiency

scholarly journals Modeling stomatal conductance in the earth system: linking leaf water-use efficiency and water transport along the soil–plant–atmosphere continuum

2014 ◽  
Vol 7 (5) ◽  
pp. 2193-2222 ◽  
Author(s):  
G. B. Bonan ◽  
M. Williams ◽  
R. A. Fisher ◽  
K. W. Oleson
Keyword(s):  
Soil Moisture ◽  
Stomatal Conductance ◽  
Water Use Efficiency ◽  
Water Use ◽  
Functional Dependence ◽  
Moisture Stress ◽  
Leaf Water ◽  
Carbon Gain ◽  
Soil Moisture Stress ◽  
Use Efficiency

Abstract. The Ball–Berry stomatal conductance model is commonly used in earth system models to simulate biotic regulation of evapotranspiration. However, the dependence of stomatal conductance (gs) on vapor pressure deficit (Ds) and soil moisture must be empirically parameterized. We evaluated the Ball–Berry model used in the Community Land Model version 4.5 (CLM4.5) and an alternative stomatal conductance model that links leaf gas exchange, plant hydraulic constraints, and the soil–plant–atmosphere continuum (SPA). The SPA model simulates stomatal conductance numerically by (1) optimizing photosynthetic carbon gain per unit water loss while (2) constraining stomatal opening to prevent leaf water potential from dropping below a critical minimum. We evaluated two optimization algorithms: intrinsic water-use efficiency (ΔAn /Δgs, the marginal carbon gain of stomatal opening) and water-use efficiency (ΔAn /ΔEl, the marginal carbon gain of transpiration water loss). We implemented the stomatal models in a multi-layer plant canopy model to resolve profiles of gas exchange, leaf water potential, and plant hydraulics within the canopy, and evaluated the simulations using leaf analyses, eddy covariance fluxes at six forest sites, and parameter sensitivity analyses. The primary differences among stomatal models relate to soil moisture stress and vapor pressure deficit responses. Without soil moisture stress, the performance of the SPA stomatal model was comparable to or slightly better than the CLM Ball–Berry model in flux tower simulations, but was significantly better than the CLM Ball–Berry model when there was soil moisture stress. Functional dependence of gs on soil moisture emerged from water flow along the soil-to-leaf pathway rather than being imposed a priori, as in the CLM Ball–Berry model. Similar functional dependence of gs on Ds emerged from the ΔAn/ΔEl optimization, but not the ΔAn /gs optimization. Two parameters (stomatal efficiency and root hydraulic conductivity) minimized errors with the SPA stomatal model. The critical stomatal efficiency for optimization (ι) gave results consistent with relationships between maximum An and gs seen in leaf trait data sets and is related to the slope (g1) of the Ball–Berry model. Root hydraulic conductivity (Rr*) was consistent with estimates from literature surveys. The two central concepts embodied in the SPA stomatal model, that plants account for both water-use efficiency and for hydraulic safety in regulating stomatal conductance, imply a notion of optimal plant strategies and provide testable model hypotheses, rather than empirical descriptions of plant behavior.

scholarly journals Reducing the Evaporative Demand Improves Photosynthesis and Water Use Efficiency of Indoor Cultivated Lettuce

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1396
Author(s):  
Chiara Amitrano ◽  
Youssef Rouphael ◽  
Antonio Pannico ◽  
Stefania De Pascale ◽  
Veronica De Micco
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Net Photosynthesis ◽  
Carbon Gain ◽  
Specific Response ◽  
Crop Water ◽  
Evaporative Demand ◽  
Crop Water Use ◽  
Better Regulation ◽  
Use Efficiency

Currently, climate change is affecting considerably the availability of freshwater for agriculture, increasing the need for the optimization of crop water use efficiency. Attempts to use VPD (vapor pressure deficit) modulation to reduce water consumption have been made. However, the effects of VPD on leaf stomatal and hydraulic traits, and on possible tradeoffs between photosynthetic carbon gain and transpiration, are rarely reported. We analyzed photosynthesis (gas-exchange, photochemistry) stomatal and hydraulic-related traits of green (G) and red (R) butterhead lettuce (Lactuca sativa L.) grown under low and high VPD (LV, HV) in a controlled environment. Our results showed that plants developed a higher number of small stomata under LV, allowing better regulation over opening/closing mechanisms and thus increasing net photosynthesis by 18%. LV plants also achieved better performance of the photosystem II and a more efficient water use (increments in ΦPSII and iWUE by 3% and 49%), resulting in enhanced plant growth and reduced need for irrigation. Significant differences between G and R plants were limited to a few traits, and the physiological response under the two VPDs did not show cultivar-specific response. We discuss the role of VPD management as necessary to maximize crop water use by harmonizing photosynthesis and transpiration.

Limitations to photosynthetic carbon gain in timberline Abies lasiocarpa seedlings during prolonged drought

2007 ◽  
Vol 37 (3) ◽  
pp. 568-579 ◽  
Author(s):  
Daniel M. Johnson ◽  
William K. Smith
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Water Status ◽  
Early Summer ◽  
Leaf Conductance ◽  
Carbon Gain ◽  
Forest Site ◽  
Abies Lasiocarpa ◽  
Photosynthetic Carbon ◽  
Use Efficiency

Photosynthesis, water status, and associated physiological parameters were measured in chronically drought-stressed seedlings (5 years of below-average precipitation, 107 cm net deficit) of Abies lasiocarpa (Hook.) Nutt. above (treeline ecotone site, TS) and below (forest site, FS) a Rocky Mountain timberline. In contrast to normal seasonal patterns reported for timberline conifer trees, xylem water potentials were exceptionally low in early summer and remained low for the rest of the summer. Although photosynthesis was not significantly different between the two sites, early season photosynthesis was greater than late-season photosynthesis, especially at FS. Mean daily values of leaf conductance to water vapor (gwv) and transpiration (E) were also low at the beginning of summer (gwv from 0.01 mol·m–2·s–1 to 0.13 mol·m–2·s–1 and E from 0.4 μmol·m–2·s–1 to 2.9 μmol·m–2·s–1) and continued to decrease through summer (an approximate 10-fold decrease in gwv and a 2-fold to 3-fold decrease in E), which resulted in increasing water-use efficiency as summer progressed. Although the slope of instantaneous photosynthesis – intercellular CO2 concentration curves was reduced (lower carboxylation efficiency) from July to September, the relative stomatal limitation to carbon gain was less than 50% over the entire measurement period. Mean daily intercellular CO2 concentrations decreased from near ambient levels (approximately 350–360 ppm) to 290 ppm over the course of summer. Overall, nonstomatal limitations appeared to have the largest impact on photosynthetic carbon gain, although seasonal decreases in leaf conductance and a corresponding depletion of intercellular CO2 indicated that there were also significant stomatal limitations to carbon gain that resulted in a continued regulation of greater water use efficiency.

scholarly journals Modeling stomatal conductance in the Earth system: linking leaf water-use efficiency and water transport along the soil-plant-atmosphere continuum

2014 ◽  
Vol 7 (3) ◽  
pp. 3085-3159 ◽  
Author(s):  
G. B. Bonan ◽  
M. Williams ◽  
R. A. Fisher ◽  
K. W. Oleson
Keyword(s):  
Soil Moisture ◽  
Stomatal Conductance ◽  
Water Use Efficiency ◽  
Water Use ◽  
Functional Dependence ◽  
Moisture Stress ◽  
Leaf Water ◽  
Sensitivity Analyses ◽  
Carbon Gain ◽  
Use Efficiency

Abstract. The empirical Ball–Berry stomatal conductance model is commonly used in Earth system models to simulate biotic regulation of evapotranspiration. However, the dependence of stomatal conductance (gs) on vapor pressure deficit (Ds) and soil moisture must both be empirically parameterized. We evaluated the Ball–Berry model used in the Community Land Model version 4.5 (CLM4.5) and an alternative stomatal conductance model that links leaf gas exchange, plant hydraulic constraints, and the soil–plant–atmosphere continuum (SPA) to numerically optimize photosynthetic carbon gain per unit water loss while preventing leaf water potential dropping below a critical minimum level. We evaluated two alternative optimization algorithms: intrinsic water-use efficiency (Δ An/Δ gs, the marginal carbon gain of stomatal opening) and water-use efficiency (Δ An/Δ El, the marginal carbon gain of water loss). We implemented the stomatal models in a multi-layer plant canopy model, to resolve profiles of gas exchange, leaf water potential, and plant hydraulics within the canopy, and evaluated the simulations using: (1) leaf analyses; (2) canopy net radiation, sensible heat flux, latent heat flux, and gross primary production at six AmeriFlux sites spanning 51 site–years; and (3) parameter sensitivity analyses. Without soil moisture stress, the performance of the SPA stomatal conductance model was generally comparable to or somewhat better than the Ball–Berry model in flux tower simulations, but was significantly better than the Ball–Berry model when there was soil moisture stress. Functional dependence of gs on soil moisture emerged from the physiological theory linking leaf water-use efficiency and water flow to and from the leaf along the soil-to-leaf pathway rather than being imposed a priori, as in the Ball–Berry model. Similar functional dependence of gs on Ds emerged from the water-use efficiency optimization. Sensitivity analyses showed that two parameters (stomatal efficiency and root hydraulic conductivity) minimized errors with the SPA stomatal conductance model. The critical stomatal efficiency for optimization (ι) was estimated from leaf trait datasets and is related to the slope parameter (g1) of the Ball–Berry model. The optimized parameter value was consistent with this estimate. Optimized root hydraulic conductivity was consistent with estimates from literature surveys. The two central concepts embodied in the stomatal model, that plants account for both water-use efficiency and for hydraulic safety in regulating stomatal conductance, imply a notion of optimal plant strategies and provide testable model hypotheses, rather than empirical descriptions of plant behavior.

scholarly journals Drying times: plant traits to improve crop water use efficiency and yield

2020 ◽  
Vol 71 (7) ◽  
pp. 2239-2252 ◽  
Author(s):  
Anthony G Condon
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Plant Traits ◽  
Simulation Modelling ◽  
Carbon Gain ◽  
Crop Water ◽  
Evaporative Demand ◽  
Crop Water Use ◽  
Crop Simulation ◽  
Use Efficiency

Abstract Crop water use efficiency (WUE) has come into sharp focus as population growth and climate change place increasing strain on the water used in cropping. Rainfed crops are being challenged by an upward trend in evaporative demand as average temperatures rise and, in many regions, there is an increased irregularity and a downward trend in rainfall. In addition, irrigated cropping faces declining water availability and increased competition from other users. Crop WUE would be improved by, first, ensuring that as much water as possible is actually transpired by the crop rather than being wasted. Deeper roots and greater early crop vigour are two traits that should help achieve this. Crop WUE would also be improved by achieving greater biomass per unit water transpired. A host of traits has been proposed to address this outcome. Restricting crop transpiration through lower stomatal conductance is assessed as having limited utility compared with traits that improve carbon gain, such as enhancements to photosynthetic biochemistry and responsiveness, or greater mesophyll conductance. Ultimately, the most useful outcomes for improved crop WUE will probably be achieved by combining traits to achieve synergistic benefit. The potential utility of trait combinations is supported by the results of crop simulation modelling.

Water demand and water use efficiency of winter barley in Hungary

2011 ◽  
Vol 59 (1) ◽  
pp. 13-22
Author(s):  
Z. Varga-Haszonits ◽  
E. Enzsölné Gerencsér ◽  
Z. Lantos ◽  
Z. Varga
Keyword(s):  
Soil Moisture ◽  
Water Supply ◽  
Water Use Efficiency ◽  
Water Use ◽  
Potential Evapotranspiration ◽  
Growth Period ◽  
Winter Barley ◽  
Potential Yield ◽  
Yield Data ◽  
Use Efficiency

The temporal and spatial variability of soil moisture, evapotranspiration and water use were investigated for winter barley. Evaluations were carried out on a database containing meteorological and yield data from 15 stations. The spatial distribution of soil moisture, evapotranspiration and water use efficiency (WUE) was evaluated from 1951 to 2000 and the moisture conditions during the growth period of winter barley were investigated. The water supply was found to be favourable, since the average values of soil moisture remained above the lower limit of favourable water content throughout the growth period, except for September–December and May–June. The actual evapotranspiration tended to be close to the potential evapotranspiration, so the water supplies were favourable throughout the vegetation period. The calculated values of WUE showed an increasing trend from 1960 to 1990, but the lower level of agricultural inputs caused a decline after 1990. The average values of WUE varied between 0.87 and 1.09 g/kg in different counties, with higher values in the northern part of the Great Hungarian Plain. The potential yield of winter barley can be calculated from the maximum value of WUE. Except in the cooler northern and western parts of the country, the potential yield of winter barley, based on the water supply, could exceed 10 t/ha.

scholarly journals Reducing the Excessive Evaporative Demand Improved the Water-use Efficiency of Greenhouse Cucumber by Regulating the Trade-off between Irrigation Demand and Plant Productivity

HortScience ◽  
2018 ◽  
Vol 53 (12) ◽  
pp. 1784-1790 ◽  
Author(s):  
Dalong Zhang ◽  
Yuping Liu ◽  
Yang Li ◽  
Lijie Qin ◽  
Jun Li ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Use Efficiency ◽  
Water Flow ◽  
Water Use ◽  
Plant Productivity ◽  
Plant Water ◽  
Evaporative Demand ◽  
Plant Water Stress ◽  
Irrigation Demand ◽  
Use Efficiency

Although atmospheric evaporative demand mediates water flow and constrains water-use efficiency (WUE) to a large extent, the potential to reduce irrigation demand and improve water productivity by regulating the atmospheric water driving force is highly uncertain. To bridge this gap, water transport in combination with plant productivity was examined in cucumber (Cucumis sativus L.) grown at contrasting evaporative demand gradients. Reducing the excessive vapor pressure deficit (VPD) decreased the water flow rate, which reduced irrigation consumption significantly by 16.4%. Reducing excessive evaporative demand moderated plant water stress, as leaf dehydration, hydraulic limitation, and excessive negative water potential were prevented by maintaining water balance in the low-VPD treatment. The moderation of plant water stress by reducing evaporative demand sustained stomatal function for photosynthesis and plant growth, which increased substantially fruit yield and shoot biomass by 20.1% and 18.4%, respectively. From a physiological perspective, a reduction in irrigation demand and an improvement in plant productivity were achieved concomitantly by reducing the excessive VPD. Consequently, WUE based on the criteria of plant biomass and fruit yield was increased significantly by 43.1% and 40.5%, respectively.

Sign in / Sign up

Export Citation Format

Share Document