高温胁迫对小麦花药活性氧代谢的影响

Effect of High-Temperature Stress on Reactive Oxygen Metabolism of Wheat Anther

为研究小麦花药在高温胁迫下的氧化应答机制,以正常生长条件下和高温胁迫(42±1)℃下不同发育时期的花药(单核后期、二核期和三核期)为供试材料,比较分析了小麦花药中超氧阴离子自由基(O-2)生成速率、过氧化氢(H2O2)和丙二醛(MDA)含量以及主要抗氧化酶活性的变化。结果表明,在高温胁迫后,小麦花药的整个发育时期O-2的生成速率、H2O2和MDA的含量均显著高于对照组,其中O-2生成速率呈现出由低到高平衡上升的趋势,在单核后期高温胁迫处理与对照之间的差异则高于其他花药发育时期;而高温胁迫后的H2O2和MDA含量在二核期与对照组呈现较大差异。同时,高温胁迫下不同时期花药中SOD、POD和CAT的活性均显著低于对照。由此可知,高温胁迫打破了小麦花药内活性氧与抗氧化体系代谢之间的动态平衡,并随着花药的发育而不断加剧,使小麦花药长期处于严重的氧胁迫环境中而造成败育。

In order to reveal the mechanism of oxidative response in wheat anthers under high temperature stress,wheat anthers under high-temperature stress(42±1)℃at different developmental stages(later-uninucleate stage,binucleate stage,and trinucleate stage)were used to determine the rate of superoxide anion(O-2),the content of hydrogen peroxide(H2O2)and malondialdehyde(MDA),and the activities of major antioxidant enzymes.The results showed that after high-temperature stress,the O-2 production rate,H2O2 and MDA content in wheat anther were significantly higher than those in the control,and the O-2production rate showed a trend of“low-high”,and the difference between the high-temperature stress and control at the later-uninucleate stage was higher than that at other development stages.However,the H2O2 and MDA contents in the high-temperature stress and the control was significantly different at the binucleate stage.Meanwhile,the activities of SOD,POD and CAT under high temperature stress were significantly lower than those in the control.Accordingly,high-temperature stress broke the balance between the production of reactive oxygen species and the metabolism of antioxidant system in wheat anther,and it was intensified with the development of anther,making the wheat anther at the critical period of development in a serious oxygen stress environment for a long time and causing abortion.