AM真菌提高宿主植物耐受重金属胁迫的生理机制

本文围绕重金属胁迫条件下丛枝菌根（AM）真菌的生理生态响应特征，从生理和分子水平上综述AM真菌对重金属离子吸收和控制的机理：1）AM真菌菌丝的吸附作用减缓重金属向植物地上部分的迁移，从而达到保护植物免受重金属毒害的目的；2）AM真菌的菌丝体分泌物与重金属之间的螯合作用；3）AM真菌促进宿主植物对矿质营养元素的吸收；4）调节重金属在宿主植物地上部分和地下部分的分布；5）AM真菌调节宿主植物体内抗氧化酶的活性和内源激素的水平；6）AM真菌调节参与吸收和转运重金属离子的基因的表达。综上所述，本文提出在广泛调查、筛选超累积菌根植物的基础上，不断探索植物－微生物－菌根复合体的修复机制，并结合基因工程技术，以促进重金属污染土壤的生物修复。

Mechanism of plant tolerance to heavy metals enhanced by arbuscular mycorrhizal fungi

Arbuscular mycorrhizae (AM) are the symbionts between AM fungi and plant roots in natural and artificial ecosystems. AM symbionts could decrease the harmful stress from heavy metals and regulate the heavy metals uptake and translocate to their host plants. In order to discover the physiological and molecular mechanism of heavy metals tolerance induced by AM fungi, the function and strategies of AM symbionts were discussed in this paper: 1) the fungal hyphae could immobilize heavy metals and restrict the translocation of heavy metals from roots to shoots; 2) chelating substances could immobilize heavy metals; 3) AM fungi could promote the nutrient acquisition to host plants; 4) AM fungi could regulate the distribution of heavy metals in host plants; 5) AM fungi could influence the anti oxidative enzymes system activity and hormones in host plants; 6) the molecular mechanisms that AM fungi regulate heavy metal uptake and translocation. On the basis, this study focused on the possibility of using the system of AM soil microbiology host plant for remediation of heavy metals polluted soil in future.