植物根系分泌物对土壤污染修复的作用及影响机理

生物修复是一种经济环保的土壤修复技术。根系分泌物是利用生物修复污染土壤过程中的关键物质，也是植物与土壤微生物进行物质交换和信息传递的重要载体，在植物响应污染物胁迫中扮演重要角色。研究植物根系分泌物对土壤污染修复的作用和影响机理，是深入理解植物和微生物环境适应机制的重要途径，对促进生物修复污染土壤有重要指导意义。从污染物胁迫对根系分泌物的影响、根系分泌物对土壤污染物环境行为的影响、根系分泌物在调控污染土壤中根际微生物群落结构和多样性中发挥的作用等几个方面综述了根系分泌物对土壤污染修复的影响及内在机制。研究结果表明，根系分泌物在降低重金属对植物的毒性、加速有机污染物降解等方面有非常重要的作用。根系分泌物对土壤微生物的丰度和多样性均有显著影响，其与根际微生物互作在土壤污染物的消减中发挥了重要的调控作用。在此基础上，提出了以往研究中的不足，并对污染物胁迫下根系分泌物未来研究的方向和趋势进行了展望。

Effects and mechanisms of plant root exudates on soil remediation

Bioremediation is an environment friendly and economically feasible remediation technology. Plant root exudates, playing an active role in root-microbe communications, are the key substances in bioremediation processes of soil contamination. Understanding the effects and mechanisms of plant root exudates on soil remediation can provide a better guidance with bioremediation techniques. Moreover, it is also helpful to understand the adapted mechanisms of plants and microbial communities in contaminated soils. In this paper, the effects of contaminants on the characteristics of root exudates, the effects of root exudates on the environmental behaviors of contaminants in soils were studied. Furthermore, the roles and mechanisms of root exudates in regulating the diversity of the rhizosphere microbial communities were also reviewed to reveal the effects and mechanisms of plant root exudates in the remediation of soil contaminants. The results indicated that root exudates played an important role in reducing the toxicity of metal(loid)s to plants, and also in accelerating the degradation of organic pollutants. Besides, root exudates had significant effects on the abundance and diversity of soil microorganisms. Interactions of root exudates with rhizosphere microorganisms played an important role in the reduction of soil contaminants. On this basis, current knowledge gaps and future research directions of root exudates under the stress of soil contaminants are also identified.