Bacillus thuringiensis P34与海泡石联合阻控蔬菜积累铅和改良土壤的作用

Synergistic effect of Bacillus thuringiensis P34 and sepiolite on lead uptake of vegetables and remediation in Pb-contaminated soils

本研究为建立微生物-吸附剂联合钝化修复技术,以期为重金属污染农田的修复和蔬菜安全生产提供试验依据。在南京市栖霞区某矿区周边农田开展田间试验,探究了Bacillus thuringiensis P34及海泡石(S)对辣椒(苏椒五号)和茄子(苏琦一号)的生长、Pb积累和营养品质的影响,评估复配处理(P34+S)改良蔬菜根际土壤理化性质的作用。结果表明,与对照相比,海泡石可显著降低蔬菜果实Pb含量,菌株P34和海泡石复配可进一步显著降低辣椒和茄子果实Pb含量(58%和26%)。与对照相比,复配处理可显著使辣椒果实生物量增加1.5倍,改善蔬菜的营养品质,还能提高根际土壤pH、芽孢细菌数量、蔗糖酶和脲酶活性,显著降低根际土壤DTPA提取态Pb含量,并显著增加>1 mm团聚体的比例、显著减少<0.25 mm团聚体的比例。将B. thuringiensis P34与海泡石联合施用于Pb污染土壤,可显著阻控茄果类蔬菜积累Pb并提高其营养品质,显著改善根际土壤的理化性质,具有修复Pb污染土壤、保障蔬菜安全生产的潜力。

In this study, a microbe-adsorption immobilization method was used to test the in situ remediation and safe production of vegetables in heavy metal contaminated farmlands. Field experiments were carried out on a lead-contaminated farmland adjacent a mine region in Qixia, Nanjing. The effects of Bacillus thuringiensis P34, sepiolite(S). and P34+S treatment on the growth, Pb accumulation, and nutritional quality of eggplants(SQ-I)and peppers(SJ-V), were assessed. The influence of the treatments on the physical and chemical properties of the plant rhizosphere soil was also analyzed. The Pb content of the eggplant and pepper fruits was significantly reduced by sepiolite,compared to the control. Furthermore, the P34+S treatment significantly reduced the Pb content of pepper and eggplant fruits by 58% and 26%, respectively. The biomass and nutritional quality of pepper fruits increased. Notably, the P34+S treatment significantly increased the pH, the number of spore-forming bacteria, the urease-sucrase activities and the amount of >1 mm aggregates in plant rhizosphere soils. On the other hand, it decreased the DTPA-extracted Pb content and the amount of <0.25 mm aggregates in plant rhizosphere soils. Our results show that the synergistic amendment of P34 and sepiolite can be used efficiently to stabilize and reclaim Pb-contaminated farmlands, inducing a low Pb uptake by vegetables and improving soil quality.