土壤水分状况对花生和早稻叶片气体交换的影响

通过田间测坑试验研究了长期处于不同土壤水分状况下花生和早稻叶片气体交换的一些特点.结果表明，花生分枝期轻度和中度水分胁迫使气孔导度(Gs)和蒸腾速率(Tr)略有下降，净光合速率(Pn)和叶片水分利用效率(WUE)减小，轻度水分胁迫Gs/Tr略有上升而中度胁迫Gs/Tr变小.花生结荚期轻度和中度水分胁迫都使Gs、Tr、Gs/Tr和Pn显著降低，WUE大幅度上升.花生结荚期明显受土壤水分胁迫影响.早稻灌浆期轻度和中度水分胁迫Gs、Tr和Gs/Tr变化不显著，Pn和WUE增加，并且轻度水分胁迫下籽粒产量增加.Gs和Gs/Tr变化情况相结合可以作为作物水分胁迫程度的一个参考指标，即如果Gs和Gs/Tr同时下降则作物已经受到水分胁迫影响.

Effects of soil water status on gas exchange of peanut and early rice leaves

The gas exchange characteristics of peanut and early rice leaves were investigated in experimental plots under different soil water conditions over a long growth period.The results showed that at the branching stage of peanut,the stomatal conductance(Gs)and transpiration rate(Tr)decreased slightly under mild and moderate soil water stress,while the net photosynthetic rate(Pn)and leaf water use efficiency (WUE) increased.The Gs/Tr ratio also increased under mild water stress,but decreased under moderate water stress.At podding stage,the Gs,Tr,Gs/Tr ratio and Pn decreased,while WUE increased significantly under mild and moderate water stress.The peanut was suffered from water stress at its pod setting stage.At the grain filling stage of early rice,the Gs,Tr and Gs/Tr ratio fluctuated insignificantly under mild and moderate water stress,while Pn and WUE increased significantly,with an increase in grain yield under mild water stress.It's suggested that the combination of Gs and Gs/Tr ratio could be a reference index for crop water stress,namely,crops could be hazarded by water stress when Gs and Gs/Tr decreased synchronously.