Biochar has various ecological effects on heavy metal-contaminated soils. Biochar can be used to passivate the activity of heavy metals and improve environmental conditions for microbial growth. A greenhouse pot experiment was conducted to explore the diversity of microbes in red soil under cadmium (Cd) stress following the application of wheat straw biochar. The contaminant Cd was prepared at 2.5 mg kg^‒1 with deionized water to simulate the heavy metal pollution of red soil under natural conditions, and the proportions of wheat straw biochar used were 2.5% and 10%. The complete genetic diversity of red soil bacteria in this study was evaluated using high-throughput sequencing. The results showed that the bacterial genetic diversity of Cd-contaminated red soils was restored with biochar treatment, and recovery with 2.5% biochar was significant. Biochar significantly affected the richness of soil bacteria by 6.79%–21.04%. Forty-three phyla of bacteria, including Proteobacteria, Acidobacteria and Gemmatimonadetes, constituted the bacterial community in the red soils. Further principal component analysis showed that Cd pollution and biochar application collectively affected the bacterial genetic diversity. Hydrogenophaga, Rubrivivax, Haliscomenobacter, Citrobacter, Methylibium and Azospirillum were indicator strains for Cd-contaminated red soils, while Steroidobacter, Bradyrhizobium, Anaerolinea, Chloronema Dubinina and Gorlenko were key strains for the biochar remediation of Cd contamination. In conclusion, for soil polluted with 2.5 mg kg Cd^‒1, the application of 2.5% wheat straw biochar significantly increases soil microbial abundance and genetic diversity and plays an active role in improving the soil micro-ecosystem.

中文翻译：

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生物炭对镉污染土壤细菌遗传多样性的影响

生物炭对重金属污染的土壤具有多种生态影响。生物炭可用于钝化重金属的活性并改善微生物生长的环境条件。应用小麦秸秆生物炭后，进行了温室盆栽实验，研究了镉（Cd）胁迫下红壤中微生物的多样性。制备的Cd污染物为2.5 mg kg ^‒1用去离子水模拟自然条件下红壤的重金属污染，小麦秸秆生物炭的使用比例分别为2.5％和10％。使用高通量测序对本研究中红壤细菌的完整遗传多样性进行了评估。结果表明，经生物炭处理后，受镉污染的红壤细菌遗传多样性得到了恢复，而经2.5％生物炭处理后恢复显着。生物炭显着影响土壤细菌的丰富度，为6.79％–21.04％。43种细菌，包括Proteobacteria，Acidobacteria和Gemmatimonadetes，构成了红壤中的细菌群落。进一步的主成分分析表明，镉污染和生物炭的施用共同影响细菌的遗传多样性。Hydrogenophaga，Rubrivivax，Haliscomenobacter，柠檬酸杆菌属，Methylibium和固氮螺菌分别为Cd污染红壤指示器菌株，而Steroidobacter，慢生根瘤菌，Anaerolinea，Chloronema Dubinina和Gorlenko是镉污染的生物炭修复关键菌株。总之，对于被2.5 mg kg Cd ‒ ¹污染的土壤，施用2.5％的小麦秸秆生物炭显着提高了土壤微生物的丰度和遗传多样性，并在改善土壤微生态系统中发挥了积极作用。