巨大芽孢杆菌对伴矿景天修复镉污染农田土壤的强化作用

伴矿景天(Sedum plumbizincicola)是一种Cd/Zn超积累植物,常用于Cd污染土壤的植物修复。巨大芽孢杆菌(Bacillus megaterium)是一种溶磷型细菌,既可以促进植物生长,也可以提高土壤重金属生物有效性,对重金属污染土壤植物修复具有强化作用。本研究采用盆栽试验方法,分析了巨大芽孢杆菌不同接种量(10～60 mL)对伴矿景天修复Cd污染农田土壤效率的影响。结果表明: 在Cd污染农田土壤中接种巨大芽孢杆菌可以提高土壤中Cd的活性,土壤有效态Cd含量较对照(CK)增加15.0%～45.0%。与CK相比,巨大芽孢杆菌提高了伴矿景天地上和地下部的生物量,增幅分别为8.7%～66.7%和13.6%～81.8%,并显著增加了伴矿景天地上部的Cd含量,增幅在29.2%～60.4%。在种植伴矿景天并接种巨大芽孢杆菌条件下,土壤Cd去除率在26.7%～42.9%。这说明接种巨大芽孢杆菌可以促进伴矿景天的生长,增加其Cd含量,从而提高Cd污染农田土壤的修复效率。

Strengthening the effect of Bacillus megaterium on remediation of Cd-contaminated farmland soil by Sedum plumbizincicola

Sedum plumbizincicola is a Cd and Zn hyperaccumulator, widely used for the phytoremediation of Cd-contaminated soil. Bacillus megaterium, a phosphate-solubilizing bacteria, can promote plant growth and improve the bioavailability of heavy metals in soil, and thus has a strengthening effect on the remediation of heavy metal-contaminated soil. Here, a pot experiment was carried out with S. plumbizincicola as a hyperaccumulator to investigate the effects of different inoculation amounts (10-60 mL) of B. megaterium on the phytoremediation efficiency of Cd-contaminated farmland soils. The results showed that inoculation of B. megaterium increased soil available Cd content by 15.0%-45.0% compared with the CK. Biomass of shoots and roots of S. plumbizincicola increased by 8.7%-66.7% and 13.6%-81.8%, respectively. Shoot Cd concentration was significantly increased by the application of B. megaterium by 29.2%-60.4%. Under the conditions of S. plumbizincicola inoculated with B. megaterium, Cd removal rate of soil reached 26.7%-42.9%. In conclusion, application of B. megaterium in phytoremediation significantly enhanced the Cd removal efficiency and increased plant biomass, which promoted Cd remediation efficiency.