蜈蚣草修复砷和多环芳烃复合污染的根际效应及解毒机制研究

Pteris vitatta L. have been identified as the promising material for arsenic and polycyclic aromatic hydrocarbons (PAHs) co-contamination remediation with the high ability to tolerate arsenic and PAHs co-exposure, accumulate considerable arsenic and enhance PAHs dissipation. However, the critical mechanism and process of the remediation technology is not well understood, which could not provide theoretical guidance for the remediation technology application. Based on the empirical research results on the interactive effect of arsenic and PAHs co-exposure on the rhizosphere characteristics, plant physiological activity and plant accumulation process of P. vitatta, the project give the priorities to two aspects of arsenic and PAHs bioavailability in the rhizosphere and biotic stress tolerance of plant under arsenic and PAHs co-exposure. The research is prepared to be carried out by means of rhizosphere environment simulation, soil solution dynamic monitoring, plant extracting and separating, plant tissue in-situ observation and subcellular fractionation. In the research, the transformation and transportation process of arsenic and PAHs in the rhizosphere of plant is identified and the main influence factor of arsenic and PAHs bioavailability is assessed. The plant accumulation behavior and detoxification mechanism in the micro levels is analyzed. The research aims to elucidate the critical mechanism and process of remediation for arsenic and PAHs co-contamination with P. vitatta, and propose the method of improving the remediation efficiency of the phytoremediation technology. The result of the research will provide practical significance for the P. vitatta remediation of arsenic and PAHs co-contamination technology application.

蜈蚣草具有修复砷（As）和多环芳烃（PAHs）复合污染土壤潜力，但其修复关键过程和影响因素还不明确，难以为此技术应用提供理论指导。本项目在前期研究得出的As和PAHs复合胁迫对蜈蚣草吸收降解污染物行为的互作效应基础上，拟从蜈蚣草根际As和PAHs的生物有效性，以及蜈蚣草耐复合污染生物学特性两个关键问题出发，运用根际环境模拟、土壤溶液采集、植物分离提取及原位检测、亚细胞分级等手段，表征As和PAHs共存下蜈蚣草根际特征及根际污染物的迁移转化行为，探讨影响土壤As和PAHs生物有效性的关键因素；表征复合污染胁迫下蜈蚣草生理响应及污染物在微观层面的赋存形态，分析蜈蚣草对复合污染的解毒机制和吸收富集特征。项目旨在探明蜈蚣草修复PAHs和As复合污染的关键过程和作用机制，提出提高修复效率的技术方法。项目预期成果对蜈蚣草修复As-PAHs复合污染土壤技术的应用示范具有重要的理论和实际意义。

蜈蚣草具有修复砷（As）和多环芳烃（PAHs）复合污染土壤潜力，但其修复关键过程和影响因素还不明确，难以为此技术应用提供理论指导。本项目重点研究砷和PAHs复合污染胁迫的根际效应及解毒机制两个关键过程，并开展蜈蚣草修复As和PAHs复合污染优化条件摸索。结果表明，As-菲复合胁迫下蜈蚣草根际特征显著改变，表现为根系分泌物数量、有机酸构成以及酶活性等变化，以及根际微生物多样性改变，进而显著影响As和菲迁移转化。砷-菲复合胁迫改变蜈蚣草对As和菲的吸收过程，表现为改变了蜈蚣草根对菲的吸收机制，以及As的在蜈蚣草体内的还原过程、亚细胞结构分布等。通过改变土壤水分（土壤含水量30%-40%）、施加营养元素P（施加量为400-600g）可显著提高蜈蚣草修复效率。本项目揭示了蜈蚣草修复As和PAHs复合污染的关键过程和作用机制，提出提高修复效率的技术方法，对蜈蚣草修复As-PAHs复合污染土壤技术的应用示范具有重要的理论和实际意义。