控制供水对棉花叶片的光合生理特性和水分利用率的影响

控制供水处理后，棉花叶片的光合作用发生差异，４个处理叶片的光合作用都有午休现象发生，较高的土壤含水量，并没有消除午体现象的发生，较低的土壤含水量对午休也没有延长的作用，但土壤干旱明显影响了棉花的光合作用（Ｐｎ），午休期间，光合作用降低幅度较大，当土壤含水量较低时，叶片的蒸腾速率（Ｔｒ）也有较明显下降的趋势。欠水供应，虽然使棉花的水分利用效率（ＷＵＥ）有所提高，但其产量相对较低。充分供水使棉叶的光合生理处于较好状况。但其产量并不高，适水处理和适水偏旱处理，对增加产量和提高水分利用效率都是有意义的。

Effects of Controlled Irrigation on the Photosynthetic Character of Cotton Leaf and Water Use Efficiency

In field experiments in 1996,cotton Xinlouzao 4 was irrigation controlled during the whole flowering and fruiting period.Before each irrigation,the situation of soil water content were respectively heavily deficient,deficient,light deficient and sufficient.Four treatments had similar period of the midday rest of leaf neat photosynthesis,heavy deficiency decreased the leaf neat photosynthetic rate and transpiration.Deficiency and light deficiency of water increased the water use efficiency and yield of cotton.