摘要:
研究Cd2+胁迫对水培桐花树(Aegiceras corniculatum)幼苗根系丙二醛(MDA)、超氧负离子(O2·-)、过氧化物酶(POD)、过氧化氢酶(CAT)和根系活力的影响。结果显示用0.25~10 mg·L-1的Cd2+处理桐花树幼苗,幼苗根系的活力随胁迫浓度升高而下降,而其MDA、O2·-含量及POD、CAT活性均呈诱导性升高,并随Cd2+质量浓度的加大而逐渐上升,细胞内O2·-含量增大带来的膜脂过氧化增强是Cd2+污染伤害桐花树的主要原因。而根系抗氧化保护酶对0.25~10 mg·L-1的Cd2+胁迫均能起到保护性的防御作用,保护酶CAT、POD活性的增强是桐花树抗Cd2+污染过氧化伤害的主要机理之一,根系膜保护酶POD和CAT活性可以作为对环境Cd2+污染响应的生物学指标。
Abstract:
The antioxidant physiological responses to cadmium stress,including the contents of malondialaehyde(MDA),superoxide anion(O2·-),peroxide enzyme(POD),catalase(CAT),and the root system activity of Aegiceras corniculatum seedlings were investigated in water-culture condition.The results showed that,under the applications of Cd2+ in the range of 0.25-10 mg·L-1,the activity of root system decreased with increased Cd2+ concentration,while the content of O2·-,MDA,and the activities of POD and CAT increased.It revealed that the membrane-lipid peroxidation brought about by the superoxide anions was the main cause of the Cd2+ damage to Aegiceras corniculatum seedling.On the other hand,the protective enzymes exerted Cd2+ stress resistance at the Cd2+ concentrations from 0.25-10 mg·L-1.It indicated that increasing POD and CAT activities of the seedlings should be considered an important part of peroxidation resistance mechanism of the plant to cadmium pollution.And,the enzymatic activities might be a useful biological indicator of Cd2+ contamination.
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