不同时期水分调亏及不同调亏程度对冬小麦产量的影响

Effects of Water Deficits on Winter WheatYield During its Different Development Stage

用盆栽对冬小麦在不同生长时期进行不同程度的调亏试验的结果表明，冬小麦从拔节至开花期间的轻度水分亏缺对其产量有明显影响，而灌浆和返青时间的轻度水分亏缺对产量无影响。各生育时期在不同调亏水平下的产量敏感指数（或敏感系数）不同。冬小麦经过一定的亏缺处理，复水后出现生长方面的补偿效应，因而产量降低幅度与耗水量减少幅度相比要小得多。气孔阻力和叶水势对土壤水分的变动有一阈值反应，只有当土壤含水量降至田间持水量的６０％以下时，气孔阻力和叶水势才发生显著变化。

Results of pot experiments showed that even slightly water deficit from jointing to flowering stage reduced winter wheat yield, while no yield reduction was found when mild water stress was imposed at turning green stage and milky stage. At different level of water deficit, the yield sensitive index (or coefficient) to water stress varies. After winter wheat undergoes a short term of water stress and when water supply resumed, its growing speed will increase, which is the compensatory growth effect. Then yield reduction is smaller compared with the decreasing in evapotranspiration. The stomatal conductivity and leaf water potential of winter wheat decrease with the decreasing of soil water content when soil moisture is lower than 60% of field capacity, otherwise they don't change very much when it was over 60%.