锰污染土壤微生物—超富集植物联合修复机理研究

The scale and intensity of Mn mining in Guangxi ranks the first in China, resulting in serious soil pollution. Therefore, seeking for remedial methods and techniques of Mn contaminated soil is extremely urgent and necessary due to its extreme shortage in cultivable land. In this study, polygonum pubescens Bl., a newly discovered Mn hyperaccumulator, and a Mn-tolerant fungus Trichoderma harzianum separated in our lab recently will be employed as the research materials with the aim of exploring the mechanisms of soil microorganism-hyperaccumulator integrated phytoremediation and establishing an integrated remediation technology for the Mn contaminated soils. This proposed research will 1) study the modes of colonization and proliferation of Trichoderma harzianum and its mechanism of Mn tolerance; 2) investigate the effect of colonization of Trichoderma harzianum to the microorganism in root micro-environment, the soil environment, the root of polygonum pubescens Bl. as well as the absorption efficiency of polygonum pubescens Bl. to Mn; 3) elucidate the interaction and counteraction of Trichoderma harzianum, polygonum pubescens Bl. and soil in the root micro-environment; 4) explore the mechanism of reinforcement of Trichoderma harzianum to polygonum pubescens Bl. on remediating Mn contaminated soil; 5) clarify the impact of colonization of Trichoderma harzianum to soil environment and the possible ecological risks and propose suitable approaches to avoid such risks. This proposed research will provide a scientific basis for the prospective application of remediation of Mn contaminated soil.

广西锰矿开采强度和规模居全国之首，土壤锰污染严重。因此，积极探寻锰污染土壤治理与修复方法显得尤为紧迫和必要。本项目拟以课题组最近初步筛选出的耐Mn微生物哈茨木霉菌(Trichoderma harzianum)以及锰超富集植物短毛蓼(Polygonum pubescens Bl.)为研究对象，以探求锰污染土壤微生物-超富集植物联合修复机理及建立微生物-超富集植物联合修复技术为目标。通过研究哈茨木霉菌在锰污染土壤中的定殖、扩繁方式及其耐锰机制，探讨哈茨木霉菌定殖对根际微环境中微生物、土壤环境、短毛蓼根系以及短毛蓼对锰吸收效率的影响；阐明哈茨木霉菌、短毛蓼、土壤在根际微环境间的相互作用机制，以及哈茨木霉菌对短毛蓼修复锰污染土壤的强化作用机理；明确哈茨木霉菌定殖对土壤环境的影响以及可能存在的生态风险，提出有效规避生态风险的途径和思路，为锰污染土壤生物修复提供理论依据。

本项目以课题组筛选出的耐Mn微生物肠杆菌(Enterobacter sp.)以及锰超富集植物短毛蓼(Polygonum pubescens Bl.)、水蓼(Polygonum hydropiper L.) 酸模叶蓼(Polygonum lapathifolium L.)等为研究对象，以探求锰污染土壤微生物-超富集植物联合修复机理及建立微生物-超富集植物联合修复技术为目标。通过研究，筛选到对锰具有良好耐性的肠杆菌菌株1株，且在锰污染土壤中具有良好的定殖、扩繁速度；肠杆菌的定殖促进了超富集植物的生长，增加了土壤Mn的有效态含量，提高了超富集植物根、茎、叶中Mn的含量，大大提高了超富集植物对锰污染土壤的修复效率，且无生态风险。在大田试验中，以灌根和喷洒的方式接种肠杆菌，肠杆菌促进了鬼针草等对重金属的吸收效率，表明肠杆菌-超富集植物联合修复技术是一项良好的、且无生态风险的修复锰污染土壤的技术。另外，利用该项目课题组成员1人晋升为副教授，在《Plant and soil》、《Chemosphere》、《中国环境科学》等期刊共发表论文21篇，其中SCI论文14篇，申请专利2项，培养研究生3名。