电场强化博落回修复铀镉复合污染土壤机理

采用盆栽试验，研究了在0.3V/cm的外加直流电场作用下，博落回的生物量、富集铀（U）的性能和抗氧化酶活性，以及其根际土壤中有机酸含量、U和镉（Cd）的结合形态、植物根部U的价态、微生物群落结构的变化等.结果表明，施加直流电场后，博落回总生物量升高了15.33%~29.88%，其中电场+铀污染（DC+U）和电场+镉污染（DC+Cd）处理组的博落回对U和Cd的富集系数提高了90.84%和93.33%；土壤中草酸、酒石酸、琥珀酸、苹果酸和乳酸含量分别增加了18.36%~45.31%、58.62%~503.22%、15.71%~118.99%、12.34%~123.27%和25.97%~36.05%；过氧化物酶（POD）和谷胱甘肽过氧化物酶（GSH-PX）的活性分别提高了13.63%~34.82%和9.70%~28.64%；根际土壤中植物可利用态U、Cd所占比例显著增大；博落回根部的大部分U由稳定的U（IV）变成了更容易从地下部分向地上部分转移的U（VI）；酸杆菌门（Acidobacteria）等细菌菌门和子囊菌门（Ascomycota）等真菌菌门比例升高，这些微生物通过提高酶活性增强了博落回对U、Cd的耐受性和富集作用.

Mechanism for electric field enhancing remediation of uranium and cadmium co-contaminated soil by Macleaya cordata

Pot experiments were conducted to investigate variations in biomass, the accumulation performance of uranium and cadmium, and the antioxidant enzyme activities of Macleaya cordata, and in organic acid content, the speciation of uranium and cadmium, the valence state of uranium of the root, and the structure of microbe community in its rhizosphere soil under the application of DC electric field at 0.3V/cm. The results showed that the total biomass of Macleaya cordata was increased by 15.33%~29.88%, the accumulation coefficients of uranium and cadmium in DC+U and DC+Cd treatment groups were increased by 90.84% and 93.33% The proportion of available uranium and cadmium in rhizosphere soil increased, respectively, and the contents of oxalic acid, tartaric acid, succinic acid, malic acid, and lactic acid were increased by 18.36%~45.31%, 58.62%~503.22%, 15.71%~118.99%, 12.34%~123.27%, and 25.97%~36.05%, respectively, the activities of POD and GSH-PX were increased by 13.63%~34.82% and 9.70%~28.64%, respectively. The proportions of bioavailable uranium and cadmium in the rhizosphere soil were increased significantly. Moreover, the stable U(IV) in the root of Macleaya cordata was transformed to mobile U(VI), which could easily migrate from the underground part to the aboveground part of the plant, and the proportions of Acidobacteria and Ascomycota in the rhizosphere microbial community were increased, and they promoted Macleaya cordata's tolerance to and accumulation of uranium and cadmium mainly by improving enzyme activity.