| 重金属固定细菌调控土壤铁氧化物阻控小麦Cd吸收效应 |
| 摘要点击 1338 全文点击 675 投稿时间：2020-05-22 修订日期：2020-06-02 |
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| 中文关键词 重金属固定细菌 铁氧化物 铁氧化细菌 团聚体 小麦 |
| 英文关键词 heavy metal-immobilizing bacteria iron oxides Fe(Ⅱ)-oxidizing bacteria aggregate wheat |
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| 中文摘要 |
| 铁氧化物因其比表面积大，对重金属具有很强的吸附固定能力，是修复重金属污染农田良好的钝化剂.采用盆栽试验，研究重金属固定细菌Bacillus megaterium N3、Serratia liquefaciens H12和菌株N3联合H12对郑麦3号（Triticum aestivum L.，ZM-3）吸收Cd的影响，同时测定不同处理对小麦根际土壤铁氧化物含量、铁氧化细菌相对丰度、黏土颗粒矿物组成、团聚体组成和pH的影响.结果表明，功能菌株N3和H12以及N3联合H12均能显著（P<0.05）提高小麦籽粒的干重（36.5%~75.3%），显著（P<0.05）降低小麦籽粒中Cd（30.2%~84.9%）的含量.此外，相比单独施用菌株N3或者H12，施用复合菌剂N3+H12具有更强的阻控郑麦3号吸收Cd的能力.复合菌剂N3+H12主要通过提高郑麦3号根际土壤：①pH值（由6.74升高到7.08）；②Fe氧化物（67.9%）和针铁矿含量；③铁氧化细菌的相对丰度（披毛菌属和纤发菌属）和④小粒径（<0.25 mm）团聚体的含量来降低小麦根际土壤中有效态Cd的含量，进而阻控郑麦3号对Cd的吸收.本研究结果为利用重金属固定细菌修复重金属污染农田提供理论依据和技术支撑. |
| 英文摘要 |
| Iron oxides are widely distributed in soils and have large specific surface areas and strong affinities with heavy metals, and thus play a significant role in the transformation of heavy metals in soils. Pot experiments were conducted to study the effects of heavy metal-immobilizing bacteria Bacillus megaterium N3, Serratia liquefaciens H12, and strain N3 combination with H12 on the absorption of Cd by ZM-3 (Triticum aestivum L.). The effects of different treatments on soil pH, iron oxide content, and relative abundance of iron oxide bacteria, clay particle mineral composition, and aggregates in wheat rhizosphere were also measured. The results showed that strains N3, H12, and N3+H12 significantly (P<0.05) increased the dry weight (36.5%-75.3%) of wheat grains, and significantly (P<0.05) decreased the content of Cd (30.2%-84.9%) in wheat grains. Furthermore, compared with the single application of strain N3 or H12, the application of strain N3 combined with H12 had a stronger ability to reduce the absorption of Cd by ZM-3. The results suggested that strain N3, combined with H12, decreased the uptake of Cd in wheat by:①increasing the pH (from 6.74 to 7.08) of wheat rhizosphere soil; ② increasing the Fe oxide (67.9%) and goethite contents of wheat rhizosphere soil; ③ increasing the relative abundance of iron-oxidizing bacteria (Leptothrix spp. and Gallionella spp.), and ④ increasing the content of small particle size (<0.25 mm) aggregates. The results provide a theoretical basis and technical support for the use of heavy metal-immobilizing bacteria to repair farmland contaminated by heavy metals. |
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