摘要:
本文研究了链霉菌Streptomyces sp.的耐砷特性及其对蜈蚣草富集砷的影响。结果表明,Streptomyces sp.可在100 mmol ·L-1的砷酸盐溶液中生长,具有较强的抗砷毒害能力,且在48 h内对As (Ⅴ)的还原率达96.5%。施用Streptomyces sp.能促进植物对砷的吸收,蜈蚣草地上部砷浓度为930 mg·kg-1,地上部砷累积量达到对照组的2.09倍。加入Streptomyces sp.后,能促进根际土壤中As (Ⅴ)还原成As (Ⅲ),大幅度降低根际土壤残渣态砷含量,从48.15 mg·kg-1下降至28.75 mg·kg-1。Streptomyces sp.通过影响蜈蚣草根际环境,提高根际土壤pH,增加DOC含量,促使砷形态变化,从而增加砷生物可利用性。该菌可作为强化蜈蚣草修复砷污染土壤的材料。
关键词:
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砷
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抗砷微生物
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蜈蚣草
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根际
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修复
Abstract:
Streptomyces sp. showed high As-tolerance ability, which was able to grow in media containing up to 100 mmol·L-1 arsenate. As(Ⅴ) was rapidly reduced in the first 48 h, and reduction rate may reach 96.5%. Inoculation with Streptomyces sp. effectively promoted accumulation of As in Pteris vittata L. with the highest arsenic concentration in up ground parts being 930 mg·kg-1, resulting in higher arsenic accumulation (2.09 times higher) compared with the non-inoculated P. vittata L.. Streptomyces sp. can effectively promote reduction of As (Ⅴ) to As(Ⅲ), which significantly reduced the content of arsenic in residual fraction from 48.15 mg·kg-1 to 28.75 mg·kg-1. Inoculation with Streptomyces sp. influenced the rhizosphere environment. Specifically, pH and DOC concentrations increased, and the transformation of arsenic species were promoted to enhance the bioavailability. Arsenic resistant bacteria Streptomyces sp. may have the potential to enhance phytoremediation ability to arsenic-contaminated soils.
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