电子废弃物拆解区土壤重金属污染对丛枝菌根真菌多样性的影响

Effect of soil heavy metal contamination on arbuscular mycorrhizal fungal diversity in an e-waste dismantling area

摘要:

【背景】电子废弃物拆解造成的土壤重金属污染引发的环境问题日益突出，丛枝菌根(arbuscular mycorrhizal，AM)真菌能侵染植物根系并增强植物抵御环境胁迫的能力，具有重要的生态功能和应用潜力。【目的】探究电子废弃物拆解区土壤重金属污染对AM真菌群落结构与多样性的影响，甄别可耐受重金属污染的AM真菌类群。【方法】从浙江台州某典型电子废弃物拆解场地及其周边区域共采集土壤样品12份，针对土壤中AM真菌的18S rRNA基因进行高通量测序以及可操作分类单元(operational taxonomic unit，OTU)相对丰度和多样性指数计算。【结果】该区土壤中AM真菌由原囊霉目(Archaeosporales)、球囊霉目(Glomerales)和多孢囊霉目(Diversisporales)组成，其中球囊霉目占据优势地位。土壤AM真菌多样性指数与重金属的浓度、综合污染指数和潜在生态风险指数间均无显著相关性，但疑似泡囊根生囊霉(Rhizophagus vesiculiferus)的OTU相对丰度与上述重金属污染指标之间均呈显著正相关关系。【结论】R. vesiculiferus可能对重金属污染有极强耐受性，可为今后电子废弃物拆解污染土壤治理提供技术基础。

关键词:电子废弃物拆解，重金属污染，泡囊根生囊霉，丛枝菌根真菌，群落结构，多样性

Abstract:

[Background] The environmental problem caused by soil heavy metal (HM) contamination upon e-waste dismantling is becoming increasingly serious. Arbuscular mycorrhizal (AM) fungi can colonize plant root and enhance the ability of plant to resist environmental stresses, with important ecological function and application potency. [Objective] To study soil HM contamination effects on the community structure and diversity of AM fungi in e-waste dismantling areas, and to identify AM fungal species which have strong resistance to HM contamination. [Methods] A total of 12 soil samples were collected from a typical e-waste dismantling site and the surrounding areas in Taizhou city, Zhejiang province. The 18S rRNA gene of soil AM fungi was sequenced by pyrosequencing, and the relative abundances of operational taxonomic units (OTUs) and the diversity indices were calculated. [Results] Soil AM fungi in the investigated area are mainly composed by Archaeosporales, Glomerales and Diversisporales, with the dominant order of Glomerales. Although soil AM fungal diversity indices had no significant correlations with the concentrations, and the comprehensive pollution and potential ecological risk indices of HMs, the relative abundance of Rhizophagus vesiculiferus-like OTU positively correlated to all above pollution parameters of HMs. [Conclusion] R. vesiculiferus may have extremely strong resistance to HM contamination, providing technical basis for the treatment of contaminated soil caused by e-waste dismantling in the future.

Key words:E-waste dismantling, Heavy metal contamination, Rhizophagus vesiculiferus, Arbuscular mycorrhizal fungi, Community structure, Diversity