中文摘要：

为证明苹果实生树童性变化与氧化还原平衡态的相关性，采取小金海棠实生树不同节位的叶片，测定miR156相对表达量，H2O2含量以及CAT、APX和GR酶活性。结果小金海棠实生树个体生长发育过程中miR156相对表达量从1．4m高度显著降低。叶片H2O2含量，CAT、APX和GR酶活性均随节位逐渐升高。表明植物体内活性氧清除机制的CAT途径和抗坏血酸-谷胱甘肽循环均随个体发育逐渐增强。

英文摘要：

To confirm the correlation between juvenility change and redox status,leaves on different height of the trunk in Malus xiaojinensis seedlings were sampled to analyzes miR156 relative expression, H2O2 content and activities of related enzymes,catalase（CAT）,ascorbate peroxidase（APX） and glutathione reductase （GR）. The results showed that leaf miR156 expression was declined significantly from the height of 1.4 m. The leaf H2O2 content and activities of CAT, APX and GR were increased gradually with the height of nodes. These results suggested that the reactive oxygen species scavenging capacity of both CAT pathway and ascorbate-glutathione increased gradually during ontogenesis.