• 关键词：铀  美洲商陆  富集量  根际微生物群落功能多样性

• 基金项目：国防基础研究重点项目（No.B3120110001）；西南科技大学研究生创新基金（No.13ycjj46）

• 王佳
• 1. 西南科技大学生命科学与工程学院, 绵阳 621010;2. 生物质材料教育部工程研究中心, 绵阳 621010

• 罗学刚
• 1. 西南科技大学核废物与环境安全国防重点学科实验室, 绵阳 621010;2. 生物质材料教育部工程研究中心, 绵阳 621010

• 石岩
• 西南科技大学环境与资源学院, 绵阳 621010

• 摘要：在模拟低（25 mg·kg^-1）、中（50 mg·kg^-1）、高（100 mg·kg^-1）剂量铀污染的条件下，采用盆栽试验，研究了美洲商陆富集铀的特点及铀污染对根际微生物群落的影响.结果表明，铀污染对美洲商陆生长的影响可能存在一个阈值，该阈值介于25~50 mg·kg^-1之间，低于该阈值时，铀污染能够促进美洲商陆的生长，反之，则会抑制美洲商陆的生长.美洲商陆成熟时，根、茎和叶的最大铀富集量分别为131.69、9.87和45.33 μg，是一种较为理想的修复铀尾矿的植物.Biolog-Eco测试结果表明，土壤中铀会对美洲商陆根际微生物群落产生负效应，铀胁迫可使根际微生物代谢迟缓，对碳源的选择发生转移，对糖类、羧酸类和胺类碳源的利用显著减少，对酚酸类碳源的利用显著增加；同时，铀胁迫可导致根际微生物群落功能多样性指数、均匀度指数及优势微生物种类降低.最后，利用培养96 h的平均吸光值进行聚类和主成分分析.结果表明，铀胁迫下美洲商陆根际微生物群落异于对照，美洲商陆根际微生物对铀胁迫的适应是以降低对糖类、羧酸类和胺类等碳源的利用为代价的.

• Abstract：The paper imitated three (25, 50, 100 mg·kg^-1) concentration uranium contamination using pot method. The tolerance and enrichment characteristics of pokeweed (Phytolacca Americana L.) were measured, including the biomass, the plant height, stem diameter, leaf length, leaf width and the content of uranium in plant. The rhizosphere microbial community of pokeweed was studied by biolog technology. The main results showed that there might be a threshold value of uranium contamination affecting the growth of pokeweed. The threshold value might be between 25~50 mg·kg^-1. When uranium contamination was lower than this value, it facilitated pokeweed growth. However, when uranium contamination was higher than this value, it inhibited pokeweed growth. The maximum enrichment amount of uranium in pokeweed's roots, stems and leaves were 131.69 μg, 9.87 μg and 45.33 μg respectively in the mature period. Pokeweed became an ideal plant of repairing uranium tailings. Biolog-Eco test showed that uranium pollution had a negative influence on rhizosphere microbial community of pokeweed. The microbial metabolic activity was delayed. The microorganisms' choice of carbon source was transferred. Rhizosphere microbial significantly reduced the utilization of carbohydrates, carboxylic acids and amines, while they significantly increased the utilization of phenolic acids. Uranium stress caused rhizosphere microbial community functional diversity index, evenness index and dominant microbial species to be decreased. Cluster and principal component analysis of substrate reactions were performed after 96h of incubation. The results indicated that rhizosphere microbial communities of pokeweed under uranium were different from controls. The rhizosphere microbial community of pokeweed adapted to uranium at the cost of reducing the consumption of carbohydrates, carboxylic acids and amines.

• Key words：uranium  pokeweed  enrichment  functional diversity of rhizosphere microbial community

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