Effects of Water Stress on Photosynthetic Characteristics and Protective Enzyme System in Rice during Grain Filling Stage

The hybrid rice cultivar was used to study the effects of water stress on photosynthesis and protective enzyme system in rice during grain filling stage.The results indicated that leaf area of top three leaves reduced,leaf area index descended,chlorophyll content,photosynthetic rate,stomatal conductance and transpiration rate decreased,MDA content increased under water stress.And chlorophyll content,photosynthetic rate and stomatal conductance declined rapidly with the extended time.Activities of SOD,CAT and POD in leave increased obviously in 0-14 d after anthesis and subsequently decreased rapidly.At the same time,the results showed that water stress aggravated the membrane lipid peroxidation in rice leaves,resulted in the fast decline of physiological activity of leaves during grain filling stage,and promoted rice leaf senescence.