土壤水分与短期遮光对棉花光合及其气孔响应的影响

以陆地棉（Ｇｏｓｓｙｐｉｕｍ ｈｉｒｓｕｔｕｍ Ｌ．Ｚｈｏｎｇｍａｉｎ，Ｎｏ２３）为供试材料，探讨了在充分供水－水分胁迫－复水的处理过程中，短期不同遮光水平对棉花光合特性及其气孔响应的影响。结果表明，在水分处理过程中，所有不同遮光水平的棉花叶片对短期遮光具有相似的基本响应规律；短期遮光使净光合速率迅速降低，气孔导度减少，但减少速率缓慢；遮阳网去掉后，叶片气 重新开放速率和光合恢复被延迟，水分胁迫期

Effects of soil moisture and short-term shade on photo-synthetic and stomatal response in cotton leaves

Effects of different short term shade levels on photosynthetic characteristics and stomatal response in upland cotton ( Gossypium hirsutum L.Zhongmain No.23) leaves were investigated under the well irrigation,water stress,rewatering.Results showed that all cotton leaves had similar responses to different short term shade levels.Short term shade reduced net photosynthetic rates (P n) rapidly and stomatal conductance (G s) slowly,and delayed stomatal reopening and photosynthetic recovery of cotton leaves after shading nets were removed.During water stress period,water use efficiency (WUE) was maximal,but P n lowered,photosynthetic and stomatal response to short term shade was restricted,and at 75% shade level,the negtive effects on P n,photosynthetic and stomatal response were stronger than at 40% shade level;even after rewatering,WUE was the lowest in all changed watering regimes,especially at 75% shade level.From results showed above,the effects of soil moisture and short term shade on photosynthetic and stomatal response in cotton were very remarkable.