摘要： 通过对供水和干旱下春小麦（TriticumaestivumL）和夏玉米（ZeamaysL）生理生态适应研究表明：作物水分利用效率（WUE）、光合速率（Pn）日变化受干旱缺水影响明显，干湿处理间其差别最明显时段为下午（12：00~16：00）；缺水时作物Pn在午前段以气孔限制为主，午后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。

关键词: 干旱, 作物, 水分利用效率, 光合速率, 日变化

Abstract: 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).

Key words: Drought, Crops, Water use efficiency(WUE), Photosyntheic rate(Pn), Diurnal change