水稻土砷形态转化的生物学机理与调控措施

项目名称： 水稻土砷形态转化的生物学机理与调控措施

项目编号： No.41330853

项目类型： 重点项目

立项/批准年度： 2014

项目学科： 地质学

项目作者： 赵方杰

作者单位： 南京农业大学

项目金额： 308万元

中文摘要： 由于水稻土生物地球化学过程和水稻特有的生理特性，水稻具有较强的砷累积能力，稻米是我国人口无机砷摄入的最主要来源。我国南方部分稻区受砷污染较为严重，危害粮食生产、农产品安全和人体健康。水稻土淹水后砷还原性溶解大幅度增强、砷甲基化和挥发显著增加，但其生物学机理仍不清楚。本项目申请通过现代分析化学和土壤微生物分子技术相结合，系统深入地研究水稻土固相和液相砷化学形态转化的关键机理和影响因子，探讨砷活化与铁、硫还原及与有机质结合的关系，定量测定砷甲基化和挥发通量， 建立预测水稻土砷活化的模型，揭示影响水稻土砷形态转化的关键微生物功能基因丰度、多样性和活性，分离水稻土或水稻根际亚砷酸和亚铁氧化细菌，探讨通过强化水稻根际亚砷酸和亚铁氧化过程降低砷的生物有效性，为提出减少水稻砷累积的实用措施提供理论指导。

中文关键词： 砷;土壤;形态分析;形态转化;微生物

英文摘要： Paddy rice is efficient at arsenic (As) accumulation due to a combination of the specific As biogeochemical cycle under the flooded environment and the plant physiological characteristics of rice. Rice is the most important contributor to the intake of inorganic As for the general population in China. Some paddy areas in Southern China have been seriously contaminated by As, threatening agricultural production, food safety and human health. Flooding of paddy soil leads to a massive increase in the reductive dissolution of As and a significant enhancement of As biomethylation and volatilization; however, the underlying biological mechanisms remain poorly understood. In this proposal, a suite of modern analytical techniques and soil microbial molecular methodologies will be combined to probe the key mechanisms and factors controlling As species transformation in the soil solid and solution phases. The relationship between As mobilization, iron and sulphur reduction and complexation with soil organic matter will be examined. The biomethylation and volatilization of As will be quantified. The data will be used to establish a predictive model for As mobilization in paddy soils. The abundance, diversity and expression of key microbial functional genes controlling As transformation in paddy soils will be determined. Furthermore, oxidizers of arsenite and/or ferrous iron will be isolated from paddy soils or from the rice rhizosphere. The effect of bioaugmenting arsenite or ferrous iron oxidizers in the rhizosphere on As bioavailability will be investigated. The project will provide a theoretical basis for developing practical measures to reduce As accumulation by rice.

英文关键词： Arsenic;Soil;Species analysis;Species transformation;Microorganisms