不同供水下作物水分利用效率和光合速率日变化的时段性及其机理研究

通过对供水和干旱春小麦和夏玉米生理生态适应研究表明：作物水分利用效率（ＷＵＥ）、光合速率（光合速率（Ｐｎ）日变化受干旱缺水影响明显，干湿处理间其２最明显时段为下午；缺水时作物Ｐｎ在午前段以气孔限制为主，午为段则以非气孔限制为主；缺水对ＷＵＥ日变化影响作用与叶水势，以及大气环境因素，特别是大气相对湿度和叶温关系密切。

A Study on WUE and Pn Diurnal Change Features and Its Mechanism in Crops Under Different Water Conditions

Diurnal change of water use efficiency (WUE) and net photosynthetic rate (Pn) are important processes on crop production and physiological mechanism.The paper analyzed the physio ecology adaption of spring wheat (Triticum aestinum L.)and summer corn(Zea mays L.)under different water treatment.The result showed that WUE and Pn are markedly influranced by water shortage,the most markedly time stage is in the afternoon(12-16 hr).The main way of Pn change to water shortage in the moring stage is determined mainly by stomata,and in the afternoon stage mainly by non stomata.Meanwhile,WUE and Pn reaction to water shortage condition not only related to water potential of leaf,but also to the environmental factors,especially to relative humudity(RH)and leaf temperature(Tl).