中文摘要：

研究了低温胁迫下嫁接和自根黄瓜叶片Mn-SOD、Cu／Zn．SOD和CATmRNA基因表达和酶活性变化及其与抗冷性的关系．结果表明：低温胁迫下，嫁接与自根黄瓜叶片Cu／Zn．SOD、Mn—SODmRNA基因相对表达量变化分别与其Cu／Zn—SOD、Mn．SOD活性变化相吻合，而CATmRNA相对表达量变化与其CAT活性变化并不一致；嫁接黄瓜叶片Cu／Zn．SOD和Mn—SODmRNA相对表达量及SOD、Cu／Zn—SOD和Mn-SOD活性均高于自根黄瓜，MDA含量和电解质渗漏率均低于自根黄瓜，嫁接黄瓜较高的SOD基因表达量调控的较高SOD活性是其抗冷性强于自根黄瓜的主要因素；嫁接黄瓜的功能叶CATmRNA相对表达量略高于自根黄瓜，而幼叶CATmRNA相对表达量低于后者，但两者CAT活性差异不大，说明低温胁迫对嫁接黄瓜叶片CATmRNA相对表达量及CAT活性的影响不大．

英文摘要：

This paper studied the relative expression of Mn-SOD, Cu/Zn-SOD and CAT mRNAs and the changes of SOD, Mn-SOD, Cu/Zn-SOD and CAT activities in grafted and own-rooted cucumber leaves under low temperature stress, and their relations with the cold resistance of cucumber. For both grafted and own-rooted cucumber leaves, the relative expression of Mn-SOD and Cu/Zn-SOD mRNAs under low temperature stress was respectively accordance with the changes of Mn-SOD and Cu/Zn-SOD activities, while the expression of CAT mRNA was not accordance with the change of CAT activity. The relative expression of Mn-SOD and Cu/Zn-SOD mRNAs and the activities of SOD, Mn-SOD and Cu/Zn-SOD in grafted cucumber leaves were higher than those in own-rooted cucumber leaves, while the MDA content and electrolytic leakage were in adverse. The higher SOD activity regulated by the higher SOD mRNAs expression in grafted cucumber leaves might be the key factor of grafted cucumber having a higher cold resistance to low temperature stress than own-rooted cucumber. The relative expression of CAT mRNA was slightly higher in functional leaves but lower in young leaves of grafted cucumber, while less difference was observed in CAT activity, comparing with own-rooted cucumber, which illustrated that low temperature stress had lesser effects on the relative expression of CAT mRNA and the activity of CAT in grafted cucumber leaves.