水分胁迫对3种苗木叶片渗透调节物质与保护酶活性的影响

以1 a生刺槐 （Robinia pseudoacacia）、元宝枫（Acer truncatum）和侧柏 （Platycladus oriˉ entalis）苗木为材料，通过盆栽控水试验研究了水分胁迫对3种苗木叶片丙二醛含量、 渗透调节物 质和保护酶活性的影响，并探讨了这些生理指标与其抗旱性的关系。结果表明，随胁迫 强度增大，3 种苗木的渗透调节物质游离脯氨酸和可溶性糖含量增加，而可溶性蛋白含量降低;丙二醛 （MDA） 含量随水分胁迫程度的加剧呈递增趋势;超氧化物歧化酶（SOD）、过氧化物酶（POD）和 过氧化氢 酶（CAT）活性随干旱强度增大，开始增加，而在重度胁迫时，酶活性下降，但水分胁迫 时的酶活性 始终高于正常水分时。

Effects of Water Stress on Osmotic Adjustment and Activity of Pro tect Enzymes in the Leaves of Three Sorts of Seedlings

Effects of water stress on the content of malondialdehyde （ MDA）， osmotic adjustment and proˉ tect enzymes in the leaves of oneˉyearˉold Robinia pseudoacacia， A cer truncatum and Platycladus orienˉ talis seedlings were studied to determine the relationship between th e physiological indices and drought reˉ sistance. The results indicated that with the aggravation of water s tress， the content of free proline and soluble sugar in the leaves of the three seedlings increased，whe reas that of soluble protein decreased; the content of malondialdehyde （MDA） in the leaves tended to be incre ased with the aggravation of water stress. The activities of superoxide dismutase （SOD）， catalase （CAT ）and peroxidase （POD） with the agˉ gravation of water stress increased at beginning and then dropped u nder severe water stress， but the activiˉ ties of three protect enzymes were always higher than those under n ormal water condition.