The aim was to study the injury mechanism of Cercis chinensis seedlings under salt stress and drought stress ,and it benefited for actual production of this plant .The changes in the activities of superoxide dismutase (SOD ) and peroxidase (POD ) ,the contents of malondiadehyde (MDA) and soluble protein in leaves of Cercis chinensis seedlings treated with 100 mmol/L NaCl or 15 mmol/L PEG ,respectively ,were studied .The results showed that SOD and POD activities increased firstly and then decreased in both the treatments .The effect of PEG was more signifi-cant than that of NaCl .The contents of MDA increased in both the treatments .There was a nega-tive correlation between SOD/POD activities and MDA content .The content of protein decreased significantly in PEG treatment than in NaCl treatment .The decrease of SOD and POD activities resulted in the injury of Cercis chinensis seedlings under drought and salt stress ,w hich streng-thened the membrane lipid peroxidation and then increased MDA contents .%为了探讨紫荆在盐胁迫及干旱胁迫下发生伤害的可能机制，以1年生紫荆幼苗为试材，分别用100 mmol/L NaCl和15 mmol/L聚乙二醇（PEG）处理，分析其叶片的超氧化物歧化酶（SOD）、过氧化物酶（POD ）活性及丙二醛（M DA ）、可溶性蛋白含量的动态变化，研究盐分和干旱胁迫对紫荆幼苗膜稳定性的影响。结果表明，在NaCl和PEG处理下，紫荆幼苗SOD和POD活性先升高后降低，幼苗对PEG的反应比对NaCl的反应强烈；MDA含量显著增加，与SOD和POD活性变化呈负相关；蛋白含量降低，PEG胁迫对可溶性蛋白含量的影响大于NaCl胁迫。分析认为，紫荆幼苗在干旱和盐胁迫下发生伤害的主要原因是 NaCl及PEG处理降低了膜保护酶SOD和POD活性，从而减弱了其清除细胞内自由基的能力，加强了膜脂过氧化作用，最终导致膜脂过氧化作用产物M DA含量的增加和幼苗伤害程度的加深。
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