外源螯合剂CA和NTA对苎麻修复铅镉复合污染土壤的影响

采用盆栽实验，研究了在两组铅镉复合污染（Cd（10 mg·kg-1）/Pb（100 mg·kg-1）和Cd（50 mg·kg-1）/Pb（500 mg·kg-1））条件下，不同浓度的柠檬酸（CA）和氮三乙酸（NTA）（0,1,5,10 mmol·kg-1）对苎麻生物量、地上部分丙二醛（MDA）含量和抗氧化酶活性、苎麻各部分对Pb和Cd的积累的影响。结果表明，CA和NTA的应用均能促进苎麻的生长和提高Pb和Cd在苎麻体内积累。CA在促进苎麻生长、增强了苎麻对Cd的吸收和转移方面效果显著，但是，CA对Pb的提取和转移促进效果不显著。NTA促进苎麻对Pb的吸收和转移，并且同样有助于Cd的植物修复。苎麻体内CAT，SOD，POD活性和MDA含量变化表明CA和NTA缓解了Cd和Pb对苎麻的氧化胁迫。因此，外源螯合剂CA和NTA的应用有利于铅镉复合污染土壤的植物修复。

Effect of exogenous chelates CA and NTA on remediation of Pb and Cd-contaminated soil by ramie (Boehmerianivea (L.))

Pot experiments were conducted to investigate the influence of citric acid (CA) and nitrilotriacetic acid (NTA) levels (0, 1, 5, 10 mmol·kg-1) on the biomass, malondialdehyde (MDA) content, shoot antioxidant enzyme activities, and accumulation of cadmium (Cd) and lead (Pb) in ramie exposed to Cd (10 mg·kg-1)/Pb (100 mg·kg-1) and Cd (50 mg·kg-1)/Pb (500 mg·kg-1). The results demonstrated that CA and NTA promoted growth and increased Cd and Pb uptake in ramie. CA promoted growth and increased Cd uptake and transfer in ramie; however, no significant effect was observed on Pb uptake and transfer. Application of NTA increased Pb uptake and transfer in ramie, and also contributed to the phytoextraction of Cd. The activities of CAT, SOD, and POD, and the MDA content indicated that CA and NTA relieved oxidative stress and damage induced in ramie by Cd and Pb. Overall, exogenous chelates CA and NTA are beneficial for phytoremediation of Pb and Cd-contaminated soil.