AM真菌对重金属污染土壤生物修复的应用与机理

土壤重金属污染威胁人类健康和整个生态系统,而高效、低耗、安全的生物修复技术显示出了极大的应用潜力,特别是利用植物-微生物共生体增强生物修复效应的应用.丛枝菌根(Arbuscular Mycorrhizae,AM)真菌是一类广泛分布于土壤生态系统中的有益微生物,能与90％以上的陆生高等植物形成共生体.研究发现,AM真菌能够增强宿主植物对土壤中重金属胁迫的耐受性.当前,利用AM真菌开展重金属污染土壤的生物修复已经引起环境学家和生态学家的广泛关注.基于此,围绕AM真菌在重金属污染土壤生物修复作用中的最新研究进展,从物理性防御体系的形成、对植物生理代谢的调控、生化拮抗物质的产生、基因表达的调控等角度探究AM真菌在重金属污染土壤生物修复中的作用机理,以期为利用AM真菌开展重金属污染的生物修复提供理论依据,并对本领域未来的发展和应用前景进行了展望.

Mechanism and application of bioremediation to heavy metal polluted soil using arbuscular mycorrhizal fungi

Heavy-metal pollution in soil is a major threat to human health and the whole ecosystem, while bioremediation has become a promising option to recover the contaminated soils for its effective, non-intrusive and inexpensive. In particular, the application of symbiotic micro-organisms such as mycorrhizal fungi to enhance bioremediation efficiency has been paid more and more attention. Arbuscular mycorrhizal (AM) fungi are one of the widely spread micro-organisms, which could form symbionts with most of the vascular plants in natural or artificial ecosystem. It has demonstrated that AM symbionts could increase the stressed ability of host plants in heavy metal polluted soil. Nowadays, using bioremediation methods to recovery heavy metal polluted soils with AM fungi has been one of the hotspots in environmental and ecological science. In order to review the physiological and molecular mechanism of heavy metals tolerance induced by AM fungi, four strategies were discussed in this paper: 1) the physical defense system formation, 2) the regulation to physiological metabolism of plants, 3) the production of biochemical antagonist material and 4) the regulation of gene expression. On the basis of this, this paper indicated that the possibility of using the system of AM-soil microbiology-host plant for remediation of heavy metals polluted soil in the future. For this purpose, to enhance the studies below would be necessary: 1) molecular mechanisms that AM fungi regulate heavy metal uptake and translocation; 2) phytoremediation of polymetal-contaminated soils through selection of heavy metal tolerant AM fungi strains by genetic engineering; 3) the combination of other remediation techniques and AM-assisted bioremediation.