Cd胁迫对黄菖蒲幼苗4种抗氧化酶活性的影响

采用水培法对Cd胁迫下黄菖蒲（Iris pseudacorus L．）幼苗叶片和根系中超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）及抗坏血酸过氧化物酶（APX）的活性进行了研究。结果表明，10、40和120mg·L^-1Cd胁迫下，黄菖蒲幼苗叶片和根系中4种酶活性的变化不同。10和40mg·L^-1 cd胁迫下，黄菖蒲幼苗叶片和根系中的POD及APX活性、叶片中的SOD活性及根系中的CAT均明显高于对照；在120mg·L^-1 Cd胁迫下，叶片中的POD活性及根系中的POD和CAT活性均高于对照；各处理组根系中的SOD活性均低于对照。随处理时间的延长，40和120mg·L^-1Cd胁迫处理组叶片的CAT活性和120mg·L^-1Cd胁迫处理组根系的APX活性逐渐降低，其他处理组不同酶的活性逐渐升高或先升后降。黄菖蒲叶片及根系中的4种酶对Cd胁迫的响应能力有差异，其中POD可能是黄菖蒲耐Cd胁迫的主要抗性诱导酶。

Effect of Cd stress on the activity of four antioxidases in Iris pseudacorus seedlings

Activities of superoxide dismutase（ SOD）, peroxidase （ POD）, catalase （CAT） and ascorbate peroxidase （APX） in leaves and roots of Iris pseudacorus L. seedlings under Cd stress were studied by water culture method. The results showed that, under 10, 40 and 120 mg · L^-1 Cd stress, the changes of activities of the four enzymes in leaves and roots were different. Under 10 and 40 mg · L^-1 Cd stress, the activities of POD and APX in leaves and roots, SOD in leaves, CAT in roots were higher than those of the control. Under 120 mg · L^-1 Cd stress, the activities of POD in leaves, POD and CAT in roots were higher than that of the control. The SOD activity in roots of all treatments was lower than that of the control. As the time of treatment increased, the activity of CAT in leaves under 40 and 120 mg · L^-1 Cd stress and that of APX in roots under 120 mg · L^-1 Cd stress were decreased gradually, whereas those of the other treatments were increased gradually or increased at first and then decreased. It is concluded that the responsibility of the four enzymes to Cd stress are different, POD may be the main enzyme for inducing resistance of I. pseudacorus to Cd stress.