中文摘要：

采用聚乙二醇（PEG6000）模拟水分胁迫,研究水稻在10%PEG预处理及复水和更强的水分胁迫（15%PEG）处理条件下叶片超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）同工酶及其基因表达的变化。结果表明PEG预处理能提高叶片SOD、CAT和POD同工酶的产生,并诱导产生新谱带。当水稻受到更强的水分胁迫（15%PEG）时SOD同工酶的酶Ⅱ和Ⅳ的活性升高,并有新诱导出的酶Ⅲ参与其中;对POD而言酶Ⅱ升高,酶Ⅴ减小,并有新诱导出的酶Ⅵ参与抗氧化过程;而对CAT同工酶却有着不同的调节作用。此外,直接15%PEG胁迫（即对照组2）的Cu/Zn-SOD、APX1和CAT1基因在转录水平有明显的上调,而预处理复水组和预处理组CAT1较对照组1略有降低,预处理组APX1与对照组1相似。说明15%PEG会使水稻受到伤害,但是经过预处理后的水稻能提高抗性使其抗氧化酶基因与对照组1有着相似的表达,表明植物在遇到较强的水分胁迫时,会通过调节自身的基因表达水平来抵抗外界水分胁迫。

英文摘要：

In this paper, polyethylene glycol （PEG6000） was used to simulate water stress, and changes of superoxide dismutase （SOD）, peroxidase （POD）, isoenzyme of catalase （CAT） and gene expression in rice leaves were studied in 10% PEG pretreatment, rewater and stronger water stress （15% PEG-6000）. The results showed that PEG pretreatment improved the production of SOD, CAT and POD isozymes in leaves, and induced new isozymes. When subjected to a stronger stress, the activity of SOD isoenzyme bands Ⅱ and Ⅳ increased, and new isoenzyme band Ⅲ was observed; POD isoenzyme band Ⅱ increased while band Ⅴ decreased, and band Ⅵ of new POD isoenzyme was induced; Different isoenzymes of CAT showed different changes. In addition, Cu/Zn SOD, APX1 and CAT1 gene of direct 15% PEG- 6000 stress （control group 2） at the transcriptional level were significantly up-regulated, whereas pretreatment complex water group and pretreatment CAT1 group compared with the control group 1 decreased slightly, pretreatment group APX1 similar to the control group 1. This showed that the 15% PEG-6000 made rice be hurt, but pretreatment of rice could improve resistance to anti oxidase gene and the control group 1 had a similar expression, indicating that when encountered strong water stress, the plants could resist water stress by regulating gene expression.