Yu Qiang, Zhang Yongqiang, Liu Yunfen, Shi Peili
Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, P. R. China.
Ann Bot. 2004 Apr;93(4):435-41. doi: 10.1093/aob/mch023. Epub 2004 Feb 23.
The stomata are a key channel of the water cycle in ecosystems, and are constrained by both physiological and environmental elements. The aim of this study was to parameterize stomatal conductance by extending a previous empirical model and a revised Ball-Berry model.
Light and CO(2) responses of stomatal conductance and photosynthesis of winter wheat in the North China Plain were investigated under ambient and free-air CO(2) enrichment conditions. The photosynthetic photon flux density and CO(2) concentration ranged from 0 to 2000 micro mol m(-2) s(-1) and from 0 to 1400 micro mol mol(-1), respectively. The model was validated with data from a light, temperature and CO(2) response experiment.
By using previously published hyperbolic equations of photosynthetic responses to light and CO(2), the number of parameters in the model was reduced. These response curves were observed diurnally with large variations of temperature and vapour pressure deficit. The model interpreted stomatal response under wide variations in environmental factors.
Most of the model parameters, such as initial photon efficiency and maximum photosynthetic rate (P(max)), have physiological meanings. The model can be expanded to include influences of other physiological elements, such as leaf ageing and nutrient conditions, especially leaf nitrogen content.
气孔是生态系统中水循环的关键通道，受到生理和环境因素的制约。本研究的目的是通过扩展先前的经验模型和修正的Ball-Berry模型来参数化气孔导度。
在大气和自由空气CO₂富集条件下，研究了华北平原冬小麦气孔导度和光合作用对光和CO₂的响应。光合有效辐射通量密度和CO₂浓度分别在0至2000微摩尔·米⁻²·秒⁻¹和0至1400微摩尔·摩尔⁻¹范围内。该模型用来自光、温度和CO₂响应实验的数据进行了验证。
通过使用先前发表的光合作用对光和CO₂响应的双曲线方程，减少了模型中的参数数量。这些响应曲线在白天观测到，温度和水汽压亏缺变化很大。该模型解释了环境因素广泛变化下的气孔响应。
大多数模型参数，如初始光子效率和最大光合速率（P(max)），具有生理学意义。该模型可以扩展以纳入其他生理因素的影响，如叶片衰老和养分状况，特别是叶片氮含量。
