植物根际促生菌及丛枝菌根真菌协助植物修复重金属污染土壤的机制

Phytoremediation of heavy metal contaminated soils by plant growth-promoting rhizobacteria and arbuscular mycorrhizal fungi

摘要:

植物修复是一种前景广阔的重金属污染土壤的主要修复技术，在微生物的协助下效果更为显著。植物根际促生菌可通过分泌吲哚-3-乙酸(IAA)、产铁载体、固氮溶磷等方式促进植物生长、改善植物重金属耐受性，从而有效提高重金属污染土壤的植物修复效率。菌根真菌是土壤-植物系统中重要的功能菌群之一，可侵染植物根系改变根系形态和矿质营养状况，通过菌丝体吸附重金属，也可产生球囊霉素、有机酸、植物生长素等次生代谢产物改变重金属生物有效性。植物根际促生菌与丛枝菌根真菌可对植物产生协同促生作用，在重金属污染土壤修复中具有一定应用潜力。目前，国内外关于植物根际促生菌和丛枝菌根真菌互作已有大量研究，而二者的相互作用机理仍处于探索阶段。本文综述了近年来国内外植物根际促生菌和丛枝菌根真菌在重金属污染土壤植物修复中的作用机制，并对其研究前景进行展望。

关键词:植物根际促生菌，丛枝菌根真菌，协同作用，重金属，植物修复

Abstract:

Phytoremediation, as promising remediation technology of heavy metal contaminated soils, could be more effective when assisted by microbes. Plant growth-promoting rhizobacteria (PGPR) can promote plant growth and improve plant tolerance to heavy metals through different mechanisms, such as indole-3-acetic acid (IAA) secretion, siderophore production, nitrogen fixation or phosphorus dissolution. Arbuscular mycorrhizal fungus (AMF), as important functional microorganisms in the soil-plant system, can regulate root morphology and mineral nutrition condition by infection of plant roots, adsorb heavy metals by mycelium, and change heavy metals bioavailability by production of secondary metabolites, such as glomalin, organic acid and auxin. PGPR and AMF can have beneficial synergetic effect on plant growth and heavy metal sequestration, which offers a potential for the phytoremediation of heavy metal contaminated soils. To date, many studies have been conducted worldwide about the interaction between AMF and PGPR, but the mechanisms involved are still poorly understood. In this paper, the mechanisms driven by PGPR and AMF, representing a potential for the phytoremediation of heavy metal contaminated soils, were extensively reviewed and recommendations for future investigations were made.

Key words:Plant growth-promoting rhizobacteria (PGPR), Arbuscular mycorrhizal fungi (AMF), Synergistic effect, Heavy metal, Phytoremediation