Cd、Pb复合污染下柠檬酸对龙葵修复效率及抗氧化酶的影响

植物修复土壤重金属被普遍认为是清洁、经济的生物修复方法。为了提高生物修复土壤重金属污染的效率,在室内盆栽实验中添加柠檬酸作为螯合剂促进龙葵对重金属的吸收,并研究其生理活性的变化。结果表明:当添加柠檬酸浓度为10 nmol/kg时,龙葵生物量显著提高(P<0.05),各部分生物量表现为:茎>叶>根;随着柠檬酸浓度的增加,龙葵对重金属Cd的吸收量显著(P<0.05)增加,在10 nmol时总吸收量最大,为229.85μg/g DW;龙葵对Cd、Pb的富集系数均在柠檬酸浓度为5 nmol/kg时达到最大;Pb吸收量随柠檬酸浓度增加表现出先增大后减小的趋势;添加柠檬酸促进了龙葵对Cd的吸收,增强了抗氧化酶活性,而对Pb的吸收效果不明显。

Effect of citric acid on remediation efficiency and antioxidant enzyme of Solanum nigrum L. under Cd and Pb combined pollution

Phytoremediation of soil heavy metals is generally considered as a clean and economical method of bioremediation.In order to improve the efficiency of bioremediation,citric acid as a chelating agent was used to enhance the uptake efficiency of Solanum nigrum L.and to study the changes of its physiological activity in the indoor pot experiment.The results showed that when citric acid’s concentration was 10 nmol/kg,the biomass of Solanum nigrum L.was significantly enhanced(P<0.05),whose orders were as follows: stem>leaf>root.With the increase of the concentration of citric acid,Solanum nigrum L.had remarkably increasing absorption ability for Cd(P<0.05),and the maximum amount of Cd could reach up to 229.85 μg/g DW when citric acid’s concentration was 10 nmol/kg.It is implied that the enrichment factors of Pb and Cd could reach up to their maximum when citric acid’s concentration was 5 nmol/kg.The amount of Pb absorbed increased at the beginning and then gradually declined while critic acid’s concentration was added.It indicated that application of citric acid significantly enhanced the absorption activity for Cd and improved the activity of antioxidant enzymes of Solanum nigrum L.,but the effect of Pb absorbed was not obvious.