螯合剂和有机酸对商陆修复镉砷污染农田的影响

基于利用植物提高Cd和As复合污染农田修复效率的目标，通过大田试验方法探究了乙二胺四乙酸（EDTA）、皂素（SAP）、柠檬酸（CA）和苹果酸（MA）对商陆萃取农田土壤Cd和As的影响。结果表明，施用4种不同螯合剂和有机酸对商陆的生长没有产生不利影响，且可以显著影响商陆对土壤Cd和As的吸收积累。与对照组相比，EDTA、SAP、CA和MA处理60 d后导致商陆叶片Cd含量分别提高116.4%、55.0%、81.5%和109.9%，商陆地上部Cd积累量提高40.4%~106.0%，商陆地上部As积累量提高15.8%~55.1%。商陆各器官Cd和As的富集系数和转运系数也受螯合剂和有机酸施用的影响。施用EDTA、SAP、CA和MA均对商陆根际土壤Cd和As含量产生显著影响，SAP处理对降低商陆根际土壤Cd含量的影响最显著，而MA处理对降低商陆根际土壤As含量的影响最显著。研究表明，EDTA、SAP、CA和MA均可提高商陆萃取农田土壤Cd和As的效率，尤其是EDTA和MA的效果更好。

Effects of chelating agents and organic acids on remediation of cadmium and arsenic complex contaminated farmland by Phytolacca acinosa Roxb

With a view to improving phytoextraction efficiency, field trials were conducted to assess the effects of EDTA, saponin, citric acid (CA), and malic acid(MA)on Cd and As extraction from contaminated farmland using Phytolacca acinosa Roxb. The chelating agents and organic acids had no negative effect on Phytolacca acinose Roxb. biomass, but could significantly affect the species'' uptake and accumulation of Cd and As. 60 days after the application of EDTA, SAP, CA, and MA, leaf Cd concentrations increased to 116.4%, 55.0%, 81.5%, and 109.9% that of the control group, respectively. In the aboveground parts, applying both the chelating agents and organic acids improved the Cd and As accumulation by 40.4%-106.0% and 15.8%-55.1%, respectively, relative to the control treatment. The chelating agents and organic acids differed in their influence on Cd and As bioconcentration and transfer factors in different organs of Phytolacca acinosa Roxb. Cd and As concentrations in Phytolacca acinosa Roxb rhizosphere soil differed significantly between the control and EDTA, SAP, CA, and MA treatments. Saponin application most significantly reduced the Cd concentration, whereas MA application most significantly reduced the As concentration in Phytolacca acinosa Roxb rhizosphere soil. This work shows that EDTA, SAP, CA, and MA could be used to enhance the extraction efficiency of Cd and As by Phytolacca acinosa Roxb. and that EDTA and MA are most effective in this regard.