水分处理对大豆叶片净光合速率、蒸腾速率及水分利用效率的影响

通过对不同水分处理下大豆叶片净光合速率（Pn）、蒸腾速率（E）和水分利用效率（WUE）的测定,我们发现：不同水分处理的叶片在整个生育期内净光合速率的变化趋势基本一致,在结荚期净光合速率达到最大,其中高水处理（W3）的净光合速率明显高于低水（W1）、中水（W2）处理的净光合速率,分别是W1、W2的1.3和1.05倍;大豆叶片的蒸腾速率在花期达到最大值,在需水量较大的花期,W3的叶片比W1、W2处理的叶片蒸腾速率分别高1.26和1.08倍。从苗期到花期,由于叶片的净光合速率和蒸腾速率都以相近的速度增长,因而水分利用效率变化不大。

Effect of Soil Moisture on Soybean's Net Photosynthetic Rate,Transpiration Rate and Water Use Efficiency

The difference of the photosynthetic rate(Pn),transpiration rate(E) and water use efficiency(WUE) of soybean was observed under different soil moisture.The trend of the photosynthetic rate(Pn),whose soybeans were observed under different soil moisture,is identical in the growing stage.The photosynthetic rate(Pn)is the highest at pod stage,and that is obviously higher in W3 with great volume of demand of water than ones in W1 with low level demand of water and W2 with medium level demand of water.It is separately 1.3 and 1.05 times than ones in W1 and W2.The transpiration rate(E) of soybean leaves is up to the highest figure at flowering stage,because that is the most important period of soybean growing,and also the period of the great volume of demand of water.At the flowering stage of the great demand of water,the transpiration rate(E) of leaves in W3 with great volume of demand of water is separately 1.26 and 1.08 times than ones in W1 with low level demand of water and W2 with medium level.From seedling stage to flowering stage,the water use efficiency(WUE)varied little,because the growing speed is similar between the photosynthetic rate(Pn)and the transpiration rate(E) of soybean leaves.