博落回和竹柳间作修复铀污染土壤的研究

采用铀富集植物向日葵、博落回和竹柳进行单作与间作，开展铀污染土壤修复实验，研究了各植物富集铀的性能、根际土壤中微生物群落、有机酸含量以及铀的化学形态变化。结果表明，与单作相比，博落回和竹柳间作时，它们对铀的富集量分别提高了183.50%和24.93%，转运系数分别提高了120.31%和104.3%，修复效率最高。博落回和竹柳间作时，根际土壤中耐受菌Acidobacteria、促生菌Bradyrhizobium以及分泌有机酸真菌Aspergillus的比例显著升高，草酸和丙二酸的含量明显增加。Acidobacteria和Bradyrhizobium等细菌提高了植物对铀的耐受性能和富集性能，Aspergillus分泌的有机酸与铀形成螯合物，增加了土壤中可交换态铀的比例。这些可能是博落回和竹柳间作时修复效率显著高于两者单作时的主要机理。

Phytoremediation of Uranium Contaminated Soil by Macleaya cordata and Salicaceae in Intercropping Pattern

The uranium accumulators including Helianthus annuus, Macleaya cordata and Salicaceae were planted in monoculture and intercropping patterns to remediate uranium contaminated soils. The bioaccumulation capabilities of the plants for uranium, and the microbial communities, the organic acid contents and the transformation of uranium species in their rhizosphere soils were investigated. It is found that compared with the monoculture pattern, the bioaccumulation amounts of uranium by Macleaya cordata and Salicaceae in the intercropping pattern increase by 183.50% and 24.93%, respectively, and their translocation factors increase by 120.31% and 104.3%, respectively, showing that the phytoremediation of uranium by Macleaya cordata and Salicaceae in intercropping pattern has the highest efficiency, and the proportions of tolerant bacteria Acidobacteria, growth-promoting bacteria Bradyrhizobium and excreting organic acids bacteria Aspergillus significantly increase, and the contents of oxalic acid and malonic acid also obviously increase. Macleaya cordata and Salicaceae in intercropping pattern could remediate uranium contaminated soils more efficiently than in monoculture pattern, the main mechanism may be that the Acidobacteria and Bradyrhizobium improve their tolerance and bioaccumulation abilities for uranium, and the organic acids excreted by Aspergillus could chelate with uranium, resulting in the increase of the proportion of uranium in exchangeable fraction.