水分胁迫对水稻结实期光合特性及叶片防御酶系统的影响

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

在干旱棚内分别在正常供水和水分胁迫条件下研究了水稻结实期叶片光合特性及防御酶活性。结果表明，结实期水分胁迫下，水稻叶面积减小，叶面积系数下降，光合速率随叶绿素含量和气孔导度的下降而下降，蒸腾速率下降，MDA含量升高。随土壤水分胁迫加剧和时间延长，叶绿素含量及剑叶光合速率、气孔导度降速快、幅度大。抽穗后0～14d随胁迫时间的延长叶片SOD、CAT和POD3种酶活性升高，抽穗14d后3种酶活性又迅速下降。试验表明，水分胁迫加剧了水稻叶片膜脂过氧化程度，使水稻结实期叶片生理功能迅速衰退，加速了水稻叶片的衰老速度。

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 stomata/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 ,resuhed in the fast decline of physiological activity of leaves during grain filling stage, and promoted rice leaf senescence.