高温胁迫及恢复对水稻叶绿素荧光动力学特性和保护酶活性的影响

目的]研究高温胁迫对拔节期水稻（Oryza sativa L.）叶绿素荧光动力学参数及保护酶活性的影响。方法]水稻品种为镇稻6号。试验设1、3、5 d高温胁迫处理和高温胁迫处理5 d后恢复2 d处理,另设1个常温对照。一天中高温胁迫温度设定为：10：00,36℃;11：00,38℃;12：00,39℃;13：00,40℃;14：00,38℃;15：00,35℃。结果]与常温对照相比,高温胁迫下水稻叶绿素荧光主要参数F0变化不大;与常温对照相比,高温胁迫1、3、5 d处理Fv/Fm明显降低,但高温胁迫3、5 d处理Fv/Fm相比高温胁迫1 d处理升高,高温胁迫处理5 d后恢复2 d处理Fv/Fm与常温对照差异不大。与常温对照相比,高温胁迫1 d处理的过氧化物酶（POD）、过氧化氢酶（CAT）的活性明显增强,丙二醛（MDA）含量增加,但随着胁迫时间的延长其均逐渐降低,接近对照水平。结论]夏季高温对水稻PSⅡ反应中心造成可逆性伤害,并在保护酶的作用下逐渐修复,适应性逐渐增强,常温恢复2 d后可接近正常水平。

Effects of High Temperature Stress and Recovery on PS Ⅱ Dynamic Characteristics and Protective Enzyme Activities of Rice ( O.sativa L.)

Objective] The research aimed to study the effects of high temperature stress and recovery on PSⅡ dynamic characteristics and protective enzyme activities of rice during jointing stage.Method] The rice varieties was No.6 of Zhenjiang.The high temperature stress 1,3,5 d treatments,the recovery 2 d after high temperature stress 5 d treatment and the normal temperature control were designed.The stress temperature in one day was designed as follows: 36 ℃ at 10:00,38 ℃ at 11:00,39 ℃ at 12:00,40 ℃ at 13:00,38 ℃ at 14:00,35 ℃ at 15:00.Result] The results showed that the main PSⅡ parameters F0 of rice varied little under different high temperature stress compared with the control group.Fv/Fm of rice was significantly decreasing under high temperature stress 1,3,5 d treatments compared with the control group,but that of high temperature stress 3,5 d treatments increased compared with high temperature stress 1 d,and that of the recovery 2 d after high temperature stress 5 d treatment had no significant difference with the control group.The activities of protective enzymes such as POD and CAT were significantly enhanced and the MDA content was increased under high temperature stress 1 d treatment compared with the control group,but this trend was decreased gradually with extension of stress time,closed to the control finally.Conclusion] High temperature in summer causes irreversible damage on PSⅡ reaction center of rice,then recoveries gradually under the function of protective enzymes,and the adaptability of rice increases by degrees,is close to normal level after recovery 2 d under room temperature.