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首页> 外文期刊>Agricultural and Forest Meteorology >Towards an improved and more flexible representation of water stress in coupled photosynthesis-stomatal conductance models
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Towards an improved and more flexible representation of water stress in coupled photosynthesis-stomatal conductance models

机译：在耦合的光合作用-气孔电导模型中实现对水分胁迫的改进和更灵活的表示

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Coupled photosynthesis-stomatal conductance (A-g(s)) models are commonly used in ecosystem models to represent the exchange rate of CO2 and H2O between vegetation and the atmosphere. The ways these models account for water stress differ greatly among modelling schemes. This study provides insight into the impact of contrasting model configurations of water stress on the simulated leaf-level values of net photosynthesis (A), stomatal conductance (g(s)), the functional relationship among them and their ratio, the intrinsic water use efficiency (A/g(s)), as soil dries. A simple, yet versatile, normalized soil moisture dependent function was used to account for the effects of water stress on g(s). on mesophyll conductance (g(m)) and on the biochemical capacity. Model output was compared to leaf-level values obtained from the literature. The sensitivity analyses emphasized the necessity to combine both stomatal and non-stomatal limitations of A in coupled A-g(s) models to accurately capture the observed functional relationships A vs. g(s) and A/g(s) vs. g(s) in response to drought. Accounting for water stress in coupled A-g(s) models by imposing either stomatal or biochemical limitations of A, as commonly practiced in most ecosystem models, failed to reproduce the observed functional relationship between key leaf gas exchange attributes. A quantitative limitation analysis revealed that the general pattern of C-3 photosynthetic response to water stress may be well represented in coupled A-g(s) models by imposing the highest limitation strength to g(m), then to g(s) and finally to the biochemical capacity
机译：在生态系统模型中通常使用耦合的光合作用-气孔电导（A-g（s））模型来表示植被与大气之间的CO2和H2O交换速率。这些模型解释水分胁迫的方式在建模方案之间存在很大差异。这项研究提供了对水分胁迫的对比模型配置对净光合作用（A），气孔导度（g（s）），叶之间的功能关系及其比例，内在用水的模拟叶水平值的影响的见解。效率（A / g（s）），因为土壤干燥。使用简单但通用的归一化土壤湿度相关函数来解释水分胁迫对g（s）的影响。叶肉电导（g（m））和生化能力。将模型输出与从文献中获得的叶级值进行比较。敏感性分析强调必须在耦合的Ag（s）模型中组合A的气孔和非气孔限制，以准确捕获观察到的功能关系A vs. g（s）和A / g（s）vs. g（s） ）以应对干旱。像大多数生态系统模型中常见的那样，通过施加A的气孔或生化限制来解释耦合的A-g（s）模型中的水分胁迫，无法重现观察到的关键叶片气体交换属性之间的功能关系。定量限制分析表明，在耦合的Ag（s）模型中，通过对g（m），g（s）以及最后对g（s）施加最高的限制强度，可以很好地表示C-3对水分胁迫的光合作用的一般模式。生化能力

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