植物促生菌在重金属生物修复中的作用机制及应用

重金属污染是导致生态和环境退化的主要因素之一.土壤重金属污染会降低土壤质量、农作物产量和品质，甚至威胁人类健康.因此，优化土壤重金属污染治理措施，对于农业高产优质可持续具有重要意义.诸多国内外学者在重金属污染植物修复方面开展了大量研究，但由于受土壤和气候环境条件的影响，其修复效率受到制约.微生物与植物的协同修复被认为是环境胁迫条件下提高重金属污染修复效率的一种有效手段.耐重金属的植物促生细菌（PGPB）不仅可以促进植物生长，提高对生物胁迫（如病原菌）和非生物胁迫（如干旱、高盐、极端温度和重金属等）的抗性，还可以改变土壤中重金属的生物利用度和毒性，从而提高植物对重金属的修复效率.系统地梳理了耐重金属的PGPB在促进植物生长，增强植物抗逆性和影响重金属生物利用度方面的作用机制，并进一步综述了近年来国内外关于PGPB在生态修复中的应用和研究进展.

Mechanism and Application of Plant Growth-Promoting Bacteria in Heavy Metal Bioremediation

Heavy metal contamination is one of the main factors causing ecological and environmental degradation. Soil contamination by heavy metals decreases soil quality, reduces agricultural productivity and quality, and even threatens human health. Therefore, optimizing remediation strategies for soils polluted with heavy metals is of great significance for high-yield, good-quality, and sustainable agriculture. Numerous domestic and foreign scholars have carried out a large number of studies on the phytoremediation of heavy metal contaminated soils. However, the remediation efficiency may be restricted by soil and climatic/environmental conditions. The synergistic remediation of microorganisms and plants is considered an effective means to improve metal remediation efficiency under environmental stresses. Metal-resistant plant growth-promoting bacteria (PGPB) not only promote plant growth and its resistance to biotic (e.g., phytopathogens, etc.) and abiotic (e.g., drought, salinity, extreme temperatures, heavy metals, etc.) stresses but also alter meal bioavailability in soils and metal toxicity in plants, thereby improving phytoremediation efficiency. In this paper, the mechanisms involved in promoting plant growth and its stress tolerance, and affecting metal bioavailability by metal-resistant PGPB, were systematically summarized. Furthermore, research progress on the application of PGPB in ecological restoration in recent years was extensively reviewed.