摘要： 以2种生态型黄瓜品种为材料,在人工气候室内,研究了弱光对光系统I(PSI)水-水循环电子传递过程中一系列酶活性的影响,以期了解黄瓜苗期弱光响应的生理机制。结果表明,在弱光胁迫的早期,超氧化物歧化酶(SOD)、抗坏血酸过氧化氢酶(APX)和脱氢抗坏血酸还原酶(DHAR)活性比对照有所增加,但随着黄瓜幼苗对弱光的不断适应,3种酶活性逐渐降低。此时,耐弱光型品种(S1)叶片中的SOD、APX和DHAR活性增幅要明显高于S404,而单脱氢抗坏血酸还原酶(MDHAR)和谷胱甘肽还原酶(GR)活性在两供试材料中与对照相比均有所减弱。弱光下,S1叶片中MDHAR活性高于S404,而GR活性却低于S404。因此,耐弱光型黄瓜品种具有较高地清除活性氧和自由基的能力,可能通过调节NADPH在PS I水-水循环电子传递链中的分配来更好地适应弱光逆境。

关键词: 黄瓜, 弱光, 光系统I, 抗氧化酶

Abstract: Influences of low light on the activities of antioxidant enzymes in the electron transport of water-water cycle of PS I of two ecotypes of cucumber(Cucumis sativus L.cv.S1 and S404) seedling in artificial climatic chamber were studied.The trial aims to realize the physiology mechanism of low light response of cucumber seedlings.Results showed that,compared to the controlled condition,SOD,APX and DHAR activities in cucumber leaves were all increased during the early stage after low light treatment,but then decreased along with the treatment time delay.Increment of SOD,APX and DHAR activities in S1(tolerant to low light) leaves were larger than S404(sensitive to low light).Both MDHAR and GR activities were all decreased compared with controlled condition in S1 and S404.MDHAR activities in S1 leaves were higher than S404 under low light,while GR activities were reversed.These results suggested that low light-tolerant S1 were more potential to eliminate the active oxygen and free radicals with better low light adaptability by adjusting NADPH distribution in water-water cycle of PSI compare with low light-sensitive S404.

Key words: Cucumber, Low light, PS I, Antioxidant enzymes

中图分类号: 

• S641．2