短时水分胁迫对水稻叶片光合作用的影响

为揭示水分胁迫下水稻叶片光合特性下降的生理原因,以水培的水稻幼苗为材料,测定30%PEG-6000模拟水分胁迫150 min过程水稻叶片光合特性、荧光参数和光合机构关键酶活性的变化。结果表明:短时水分胁迫处理0~60 min气孔导度快速下降,胞间CO_2浓度、净光合速率、蒸腾速率和荧光参数均降低;60~120 min气孔导度缓慢下降,Ru BP羧化酶活性开始快速下降,胞间CO_2浓度开始上升,非光化学猝灭仍然是上升趋势,其它光合荧光参数持续降低。120 min后,非光化学猝灭出现下降趋势,Ru BP羧化酶活性和胞间CO_2浓度分别保持下降和上升趋势,其它光合荧光参数持续降低。短时胁迫处理结果暗示,光合作用0~60 min主要受气孔限制,60~120 min受气孔限制和非气孔限制共同作用,120 min后主要受非气孔限制。

The effects of short-term water stress on leaf photosynthesis in rice

In order to reveal the physiological mechanism of the reduction of photosynthesis under water stress,the change of photosynthetic and chlorophyll fluorescence characteristics and key enzymes activities of photosynthetic apparatus after 150 rmin 30％ PEG-6000 stress were investigated using rice seedling under hydroponic culture.The result indicated that stomatal conductance decreased drastically,while intercellular CO2 concentration,net photosynthetic rate,transpiration rate,and chlorophyll fluorescence parameters decreased gradually by 0 ～ 60 min of stress.During 60 ～ 120 min of stress,stomatal conductance decreased slowly,RuBP carboxylase activity began to rapidly decreased,intercellular CO2 concentration began to rise,non-photochemical quenching continued rise,other photosynthetic fluorescence parame ters continued to drop.After 120 min of stress,non-photochemical quenching began to decline,RuBP carboxylase activity and intercellular CO2 concentration showed a trend of declining and increasing respectively,while other photosynthetic fluorescence parameters declined.These results suggest that photosynthesis during 0 ～ 60 min of stress and 60 ～ 120 min of stress,and after 120 min of stress were regulated by stomatal limitation,combination of stomatal limitation and nonstomatal limitation,and non-stomatal limitation,respectively.