环境因子对小麦叶片水分利用效率影响的实验研究和数值模拟

根据现有的光合作用和蒸腾作用的模型，利用Ｂａｌｌ－Ｂｅｒｒｙ 的气孔导度模型，将叶片的光合作用模型和蒸腾作用模型结合起来，建立了光强（Ｉ）、叶片－大气水汽饱和差（ＶＰＤ）和大气ＣＯ２ 浓度（Ｃａ）等环境因子对小麦叶片水分利用效率（ＷＵＥ）影响的模型。由于这３ 种环境因子对光合、蒸腾的影响方式上的差异，作为两者之比的叶片ＷＵＥ随各环境因子的变化出现复杂的图景，同时，在人工气候箱内分别于这３ 个因子变化时对光合、蒸腾的变化作了测定，计算了叶片的Ｗ ＵＥ。测定结果与模拟结果的对比表明，在多数情况下两者符合程度良好，但在高Ｃａ下有较大的偏离

EXPERIMENTAL STUDY AND MATHEMATICAL SIMULA TION OF WATER USE EFFICIENCY IN WHEAT LEAVES AFFECTED BY SOME ENVIRONMENTAL FACTORS

By incorporating Ball Berry model of stomatal conductance into the models of photosynthesis and transpiration, a model of leaf water use efficiency (WUE) as affected by several environmental variables irradiance (I), vapor pressure deficit (VPD) and atmospheric CO 2 concentration (Ca) ] was constructed. Because the environmental variables influenced the photosynthetic rate and transpiration rate in different ways, the changes of leaf WUE with these factors were quite complicated. The rates of photosynthesis and transpiration of wheat leaves were also measured in the phytotron where the environmental variables were kept within certain ranges, and leaf WUE was calculated therefrom. The results of simulation fit quite well with the measurements except at high Ca.