硅对污染土壤-植物体系中砷环境行为的调控机制研究

项目名称： 硅对污染土壤-植物体系中砷环境行为的调控机制研究

项目编号： No.41471398

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 地质学

项目作者： 刘文菊

作者单位： 河北农业大学

项目金额： 88万元

中文摘要： 土壤砷污染直接或间接危害着人体健康，砷的生物毒性与其形态密切相关，甲基砷毒性明显小于无机砷。前期研究表明外源硅可明显降低稻米中无机砷的累积并增加了籽粒中甲基砷的比例，降低了其人体健康风险。然而就砷污染程度不同的土壤而言，硅对污染土壤-植物体系中砷环境行为的调控机制尚缺乏系统研究。本项目拟以砷污染区轻/中/重度的污染土壤和主要粮食作物-水稻和小麦为研究对象，采用土壤-植物互作的生物学模拟方法，结合高效液相-电感耦合等离子体质谱（HPLC-ICP-MS）和同步辐射分析技术，重点研究硅的施用方式、施用时期和施用量对土壤中砷形态转化及其生物有效性的影响机制，以及对水稻和小麦吸收、转化和累积砷的调控机制；探究稻田土壤溶液中Si/As比值和麦田土壤中有效Si/有效As比值与植物吸收转运和富集砷的关系；最终构建适用于砷污染区农田的硅合理施用技术体系，为砷污染土壤修复及粮食安全提供可行的技术措施。

中文关键词： 砷；硅；环境行为；植物修复；迁移转化

英文摘要： Arsenic contamination in soil has been concerned recently, especially for arsenic harmful impact on human health directly or indirectly. Most researches on arsenic biogeochemistry and the remediation of As-contaminated soils have been conducted in recent years, which provided more and more evidences to understand arsenic bio-availabilities in soils and its behaviors from soils to plants, even to edible parts. Silicon is a beneficial nutrient element for plant growth and development, especially for rice. The previous studies have proved that Si addition decreased the accumulation of As in rice straws and grains. The mechanisms of Si reducing arsenic levels in rice plants have been explored around the world. Our previous studies illustrated that Si could compete with DMA in adsorption sites of soil particles and increased the levels of DMA in soil solution, finally increased the partition of DMA in rice grains. However, the effects of Si addition on As bioavailability, mitigation and translocation in the system of contamination soil and crops when grow in arsenic contaminated soils with different As levels are not very clear, especially for plants growing in flooded soils, upland soils or soils with the rotation of flooded and non-flooded. Therefore, it is necessary to support the projects to investigate Si influences on Arsenic bioavailability in soils, and arsenic uptake, translocation and accumulation in plants cultivated in farmland contaminated by arsenic. We suppose that different Si application rates have the different effects on arsenic biogeochemistry in soil-plant system. A serial of studies will be conducted to find the mechanisms of Si how to control arsenic behaviors in the system of soil-plant (including rice, wheat) and As bioavailability in soils. Finally, the importance of Si/As ratio in soil solution of paddy soil or available Si/As in wheat soil on arsenic biogeochemistry need to be proved, and to verify the relationship between Si/As ratio in soil solution or available Si/As in wheat soil and As accumulation in edible parts of crops. Meanwhile，the suitable pathway, period and level of Si application in As-contaminated soils with different arsenic concentrations will be screened, which will provide the practical pathways to reduce As levels in edible parts of crops in As-contaminated areas.

英文关键词： Arsenic;Silicon;Environmental behaviors;Phytoremediation;Tanslocation and transformation