增强UV-C辐射作用下小麦和豌豆幼苗光合响应及其相对抗性

以小麦和豌豆为材料，研究了UV-C辐射(波长<280 nm)对叶片光合特性及抗氧化酶活性的影响.结果表明: UV-C辐射增强，可使豌豆叶片光合速率减弱，气孔导度、胞间CO₂浓度、蒸腾速率和羧化效率明显降低，而对小麦叶片上述各项指标的影响则是先增加、后降低；在UV-C辐射下，豌豆的CO₂补偿点逐渐升高，而小麦的CO₂补偿点先降低、后升高.UV-C辐射除了使豌豆的POD活性和小麦的SOD活性逐渐降低外，其他抗氧化酶活性则呈先升高、后降低的变化趋势.小麦对短时间UV-C辐射的抗性比豌豆强，但随着UV-C辐射时间的延长，小麦和豌豆的抗氧化酶活性均降低，光合作用减弱.

Photosynthetic responses of wheat and pea seedlings to enhanced UV-C radiation and their resistances

With wheat and pea seedlings as test materials,this paper studied the effects of UV-C radiation on their leaf photosynthetic characteristics and antioxidant enzyme activities.The results showed that enhanced UV-C radiation could markedly decrease the photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO2 concentration(Ci),transpiration rate(Tr)and carboxylation efficiency(CE)of pea leaves,but for wheat leaves,these parameters were increased first and decreased then.Under UV-C condition,the CO2 compensation point of leaf was increased for pea,but decreased first and increased then for wheat.With the increasing duration of UV-C radiation,the antioxidant enzyme activities of both test plants increased first and decreased then,except that the POD activity of pea and SOD activity of wheat decreased gradually.All of these suggested that wheat had a stronger resistance to short-time UV-C radiation than pea,but,with the prolonged duration of UV-C radiation,the photosynthesis and antioxidant enzyme activities of wheat and pea were all decreased.