胶质芽胞杆菌对印度芥菜根际土壤镉含量及土壤酶活性影响

采用根袋法盆栽试验,研究分别接种活菌量浓度为1×1010CFU.kg-1(处理A)和2×1010CFU.kg-1(处理C)的胶质芽胞杆菌,对根际土壤镉含量和土壤酶活性的影响.结果表明,处理A、C对根际土壤镉的去除率分别达到37.62%、38.27%,是对照(24.47%)的1.54、1.56倍.胶质芽胞杆菌处理后土壤酶活性均有所增强,土壤脲酶、磷酸酶、过氧化氢酶活性在根际土壤大于非根际,随着时间延长土壤磷酸酶活性逐渐升高,脲酶和过氧化氢酶呈现先增高后降低的变化趋势,而脱氢酶活性在非根际土壤大于根际土壤,也呈现先增高后降低的变化趋势.对照组及处理A、C组中根际Cd含量与土壤磷酸酶、脲酶呈现显著或极显著负相关.研究表明,施入胶质芽胞杆菌不仅可以提高超富集植物对土壤Cd的净化效果而且对土壤脲酶、磷酸酶、过氧化氢酶及脱氢酶均有一定的积极作用,其结果可为该菌辅助植物修复镉污染土壤的机制性研究提供理论指导.

Effects of Bacillus mucilaginosus on the Cd Content of Rhizosphere Soil and Enzymes in Soil of Brassica juncea

The effects of two inoculation concentrations of Bacillus mucilaginosus (1×10¹⁰(treatment A), 2×10¹⁰(treatment C) CFU·kg^-1) on the Cd content of rhizosphere soil and enzymes in soil were investigated when Brassica as a hyperaccumulator grew in the pots experiment. The results showed that the removal rate of rhizosphere soil Cd in treatment A and C were 37.62% and 38.27%, respectively, which were 1.54 and 1.56 times as high as that of the control (24.47%). The activities of urease, phosphatase and catalase in rhizosphere were higher than those in non-rhizosphere. The urease, catalase and dehydrogenase activities increased firstly and then decreased, while the phosphatase activity increased gradually with time. However, the dehydrogenase activity in non-rhizophere was higher than that in rhizosphere. Correlation analysis showed negative correlation between content of Cd and urease and phosphatase in the control treatment and significantly negative correlation between content of Cd and activities urease and phosphatase in treatment A and C in rhizosphere. The results indicated that inoculation of Bacillus mucilaginosus not only had some positive effect on urease, phosphatase, catalase and dehydrogenase in soil but also improved the purification effect of hyperaccumulator on soil Cd. This study provides theoretical guidance for the further mechanism study of Microbe-Phytoremediation.