Transpiration

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G L Hammer - One of the best experts on this subject based on the ideXlab platform.

  • temperature effect on Transpiration response of maize plants to vapour pressure deficit
    Environmental and Experimental Botany, 2012
    Co-Authors: Zongjian Yang, Thomas R Sinclair, Carlos D Messina, Mark E Cooper, G L Hammer
    Abstract:

    Abstract Breeding for drought tolerance can benefit from a better understanding of possible responses of Transpiration to various environmental variables. Temperature and vapour pressure deficit (VPD) are two important factors influencing stomatal conductance and Transpiration. In this study, maize ( Zea mays L.) plants of four hybrids were grown under three day/night temperature regimes (30/26, 26/22 and 22/18 °C) in glasshouses, and the response of Transpiration rate to changes in atmospheric VPD was measured at two different temperatures in a growth chamber. For all the hybrids examined, increases in Transpiration rate with increasing VPD were similar and well described by a two-segment linear regression. There was little further increase in Transpiration as VPD increased beyond a breakpoint. When measured at high temperature, the breakpoint in Transpiration response to VPD occurred at significantly higher VPD and Transpiration rate than at low temperature. The effect of growth temperature on Transpiration was evident when plants were grown at low temperature (22/18 °C) and measured at higher temperature (30 °C). However, on the second day under the measurement temperature, the Transpiration rate of these plants increased to the same level as those grown in higher day/night temperature environments. Limitation on Transpiration at high VPD is a promising trait that could be incorporated into breeding programs to improve drought tolerance in maize.

  • potential yield and water use efficiency benefits in sorghum from limited maximum Transpiration rate
    Functional Plant Biology, 2005
    Co-Authors: Thomas R Sinclair, G L Hammer, Erik Van Oosterom
    Abstract:

    Limitations on maximum Transpiration rates, which are commonly observed as midday stomatal closure, have been observed even under well-watered conditions. Such limitations may be caused by restricted hydraulic conductance in the plant or by limited supply of water to the plant from uptake by the roots. This behaviour would have the consequences of limiting photosynthetic rate, increasing Transpiration efficiency, and conserving soil water. A key question is whether the conservation of water will be rewarded by sustained growth during seed fill and increased grain yield. This simulation analysis was undertaken to examine consequences on sorghum yield over several years when maximum Transpiration rate was imposed in a model. Yields were simulated at four locations in the sorghum-growing area of Australia for 115 seasons at each location. Mean yield was increased slightly ( 5 - 7%) by setting maximum Transpiration rate at 0.4 mm h(-1). However, the yield increase was mainly in the dry, low-yielding years in which growers may be more economically vulnerable. In years with yield less than similar to 450 g m(-2), the maximum Transpiration rate trait resulted in yield increases of 9 - 13%. At higher yield levels, decreased yields were simulated. The yield responses to restricted maximum Transpiration rate were associated with an increase in efficiency of water use. This arose because Transpiration was reduced at times of the day when atmospheric demand was greatest. Depending on the risk attitude of growers, incorporation of a maximum Transpiration rate trait in sorghum cultivars could be desirable to increase yields in dry years and improve water use efficiency and crop yield stability.

Peixue Jiang - One of the best experts on this subject based on the ideXlab platform.

  • experimental investigation of Transpiration cooling with phase change for sintered porous plates
    International Journal of Heat and Mass Transfer, 2017
    Co-Authors: Gan Huang, Zhiyuan Liao, Xiaolong Ouyang, Peixue Jiang
    Abstract:

    Abstract Transpiration cooling is an effective way to protect high heat flux walls from ablation in spaceflight vehicles. Water is an effective Transpiration coolant owing to its large latent heat. This study experimentally investigated Transpiration cooling with phase change of sintered bronze porous plates in a wind tunnel with an inlet temperature of 800 K and a Reynolds number of 45000. The study investigated the effects of the coolant injection ratio and particle diameter of the sintered porous media on the Transpiration cooling efficiency. The results showed that the location of the phase change depended on the coolant injection ratio. The average cooling efficiency and maximum temperature increased as the particle diameter of the sintered bronze porous plate was reduced from 600 μm to 200 μm. However, the Transpiration cooling efficiency significantly decreased when the particle diameter further decreased to 90 μm, due to the vapor-blockage effect. The Transpiration cooling was delayed by the vapor-blockage effect with only a small mass flow rate of the liquid coolant. The delay significantly decreased with increasing injection ratio or decreasing particle diameter. The Transpiration cooling with phase change was unstable and oscillatory with the oscillation period and amplitude decreasing with decreasing coolant injection ratio or increasing particle diameter of the sintered porous plate.

  • experimental investigation of combined Transpiration and film cooling for sintered metal porous struts
    International Journal of Heat and Mass Transfer, 2017
    Co-Authors: Peixue Jiang, Gan Huang, Zhiyuan Liao, Zheng Huang
    Abstract:

    Abstract A combined Transpiration and film cooling method was evaluated experimentally for protecting struts made of sintered stainless steel porous media with film holes on the leading edge in a supersonic wind tunnel. The combined cooling results were compared to standard Transpiration cooling of the strut. Schlieren figures show that the film cooling and Transpiration cooling had little effect on the flow field stability and the shock wave profiles around the struts for the present conditions. Standard Transpiration cooling can protect most of the strut but cannot effectively cool the leading edge even with increased coolant injection pressures. The combined film and Transpiration cooling effectively cools both the leading edge and other parts of the strut. Non-uniform coolant injection with higher injection pressures in the front cavity and lower injection pressures in the back cavity more effectively utilized the limited coolant flow. The average cooling efficiency of the front part of the strut increased from 25.7% for standard Transpiration cooling to 37.9% for combined Transpiration and film cooling with the same coolant consumption using the optimal non-uniform coolant flow distribution.

Thomas R Sinclair - One of the best experts on this subject based on the ideXlab platform.

  • Assessing Transpiration estimates in tall fescue: The relationship among Transpiration, growth, and vapor pressure deficits
    Environmental and Experimental Botany, 2017
    Co-Authors: Shannon M. Sermons, Thomas R Sinclair, Thomas M. Seversike, Thomas W. Rufty
    Abstract:

    Limitations in water availability for irrigation due to drought and water-use regulations necessitate accurate approaches to estimate water use. An energy balance approach is commonly used that is inherently empirical and requires an ill-defined coefficient. An alternative is to use a relationship based on vapor pressure deficit (VPD) and plant growth to predict plant Transpiration rate. This study was undertaken to evaluate these approaches for tall fescue (Festuca arundinacea Schreb.). Experiments examined differences in water loss of tall fescue plants when grown in three temperatures with varying vapor pressure deficit (VPD), and with treatments of low nutrition and of growth regulator trinexapac-ethyl, which depressed growth. Within a temperature, the low-nutrition and growth-regulator treatments greatly affected clipping mass, however water loss remained similar. In hydroponic experiments, treatments altering clipping mass did not necessarily change total plant growth. Hence, a challenge to using whole-plant growth for estimating Transpiration of this grass is to accurately determine growth only from clipping data. Transpiration was positively correlated with VPD, especially within each temperature, but there were indications that the higher temperature treatments caused decreased plant control over Transpiration. The instability of physiological control over Transpiration highlights the potential limitations of both equations in estimating Transpiration rates.

  • temperature effect on Transpiration response of maize plants to vapour pressure deficit
    Environmental and Experimental Botany, 2012
    Co-Authors: Zongjian Yang, Thomas R Sinclair, Carlos D Messina, Mark E Cooper, G L Hammer
    Abstract:

    Abstract Breeding for drought tolerance can benefit from a better understanding of possible responses of Transpiration to various environmental variables. Temperature and vapour pressure deficit (VPD) are two important factors influencing stomatal conductance and Transpiration. In this study, maize ( Zea mays L.) plants of four hybrids were grown under three day/night temperature regimes (30/26, 26/22 and 22/18 °C) in glasshouses, and the response of Transpiration rate to changes in atmospheric VPD was measured at two different temperatures in a growth chamber. For all the hybrids examined, increases in Transpiration rate with increasing VPD were similar and well described by a two-segment linear regression. There was little further increase in Transpiration as VPD increased beyond a breakpoint. When measured at high temperature, the breakpoint in Transpiration response to VPD occurred at significantly higher VPD and Transpiration rate than at low temperature. The effect of growth temperature on Transpiration was evident when plants were grown at low temperature (22/18 °C) and measured at higher temperature (30 °C). However, on the second day under the measurement temperature, the Transpiration rate of these plants increased to the same level as those grown in higher day/night temperature environments. Limitation on Transpiration at high VPD is a promising trait that could be incorporated into breeding programs to improve drought tolerance in maize.

  • potential yield and water use efficiency benefits in sorghum from limited maximum Transpiration rate
    Functional Plant Biology, 2005
    Co-Authors: Thomas R Sinclair, G L Hammer, Erik Van Oosterom
    Abstract:

    Limitations on maximum Transpiration rates, which are commonly observed as midday stomatal closure, have been observed even under well-watered conditions. Such limitations may be caused by restricted hydraulic conductance in the plant or by limited supply of water to the plant from uptake by the roots. This behaviour would have the consequences of limiting photosynthetic rate, increasing Transpiration efficiency, and conserving soil water. A key question is whether the conservation of water will be rewarded by sustained growth during seed fill and increased grain yield. This simulation analysis was undertaken to examine consequences on sorghum yield over several years when maximum Transpiration rate was imposed in a model. Yields were simulated at four locations in the sorghum-growing area of Australia for 115 seasons at each location. Mean yield was increased slightly ( 5 - 7%) by setting maximum Transpiration rate at 0.4 mm h(-1). However, the yield increase was mainly in the dry, low-yielding years in which growers may be more economically vulnerable. In years with yield less than similar to 450 g m(-2), the maximum Transpiration rate trait resulted in yield increases of 9 - 13%. At higher yield levels, decreased yields were simulated. The yield responses to restricted maximum Transpiration rate were associated with an increase in efficiency of water use. This arose because Transpiration was reduced at times of the day when atmospheric demand was greatest. Depending on the risk attitude of growers, incorporation of a maximum Transpiration rate trait in sorghum cultivars could be desirable to increase yields in dry years and improve water use efficiency and crop yield stability.

S. Moreau - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of the sap flow determined with a heat balance method to measure the Transpiration of a sugarcane canopy
    Agricultural Water Management, 2005
    Co-Authors: R. Chabot, S. Bouarfa, D. Zimmer, C. Chaumont, S. Moreau
    Abstract:

    Sap flow measurements based on the heat balance method offers the opportunity to evaluate directly and quite easily the mass flow rate of water in plants. However, extrapolation of measurements of water use by individual stems to that for a canopy is tricky. In the present study, 14 sugarcane stems, out of a canopy of nearly 200 000, were equipped with Dynamax sap flow gauge. We extrapolated these individual measurements to determine the Transpiration of the canopy and compare this Transpiration to the crop evapoTranspiration calculated on the basis of the Penman-Monteith method. The method used for the extrapolation assumes that the Transpiration of a sugarcane plant is proportional to its leaf area. Transpiration of the canopy determined by this method was overestimated by more 35% as compared to the reference evapoTranspiration results. Different sources of possible errors were examined and lead to suppose that it is very difficult to determine the Transpiration of a heterogeneous canopy in growth by using the sap flow measurement technique.

Zongjian Yang - One of the best experts on this subject based on the ideXlab platform.

  • temperature effect on Transpiration response of maize plants to vapour pressure deficit
    Environmental and Experimental Botany, 2012
    Co-Authors: Zongjian Yang, Thomas R Sinclair, Carlos D Messina, Mark E Cooper, G L Hammer
    Abstract:

    Abstract Breeding for drought tolerance can benefit from a better understanding of possible responses of Transpiration to various environmental variables. Temperature and vapour pressure deficit (VPD) are two important factors influencing stomatal conductance and Transpiration. In this study, maize ( Zea mays L.) plants of four hybrids were grown under three day/night temperature regimes (30/26, 26/22 and 22/18 °C) in glasshouses, and the response of Transpiration rate to changes in atmospheric VPD was measured at two different temperatures in a growth chamber. For all the hybrids examined, increases in Transpiration rate with increasing VPD were similar and well described by a two-segment linear regression. There was little further increase in Transpiration as VPD increased beyond a breakpoint. When measured at high temperature, the breakpoint in Transpiration response to VPD occurred at significantly higher VPD and Transpiration rate than at low temperature. The effect of growth temperature on Transpiration was evident when plants were grown at low temperature (22/18 °C) and measured at higher temperature (30 °C). However, on the second day under the measurement temperature, the Transpiration rate of these plants increased to the same level as those grown in higher day/night temperature environments. Limitation on Transpiration at high VPD is a promising trait that could be incorporated into breeding programs to improve drought tolerance in maize.