超积累植物根-土壤界面锌镉耗竭动态及调控原理研究

项目名称： 超积累植物根-土壤界面锌镉耗竭动态及调控原理研究

项目编号： No.41201300

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 地理学

项目作者： 胡鹏杰

作者单位： 中国科学院南京土壤研究所

项目金额： 26万元

中文摘要： 连续植物修复过程中土壤重金属总量、形态及植物有效性均将显著变化，尚未有对连续修复过程重金属分配、形态变化及植物地上部重金属吸取动态表征技术方面的突破。本项目拟以锌镉超积累植物伴矿景天修复受锌镉污染土壤为对象，应用现代薄层凝胶梯度法、稳定性同位素示踪技术、同步辐射技术等，研究连续修复过程中土壤锌镉在土壤固相根际与非根际间、固液间及土壤溶液中的分配特征变化；重金属有效性下降后植物根系重金属吸收动态变化与根系生理动态，探索超积累植物对土壤重金属有效性变化的响应机制；并探索不同途径高效强化植物重金属吸收、转运的根际机制。以期从重金属形态与分配特征变化、植物对重金属活化与吸收机制角度阐明根土界面锌镉耗竭动态和机制，以及污染土壤植物连续高效修复的调控原理，为连续修复策略制定尤其是修复后期有效性下降时调控手段的选择提供理论依据。

中文关键词： 植物修复；重金属；有效性；根土界面；伴矿景天

英文摘要： The change of soil heavy metal concentration, fractions and bioavailability will occurr during repeated phytoextration by hyperaccumulator, whereas the responding mechanisms are not well understood. In this project, based on the repeated phytoextration of Zn/Cd contaminated soils with hyperaccumulator Sedum plumbizincicola, several methods including diffusive gradients in thin-films (DGT), stable isotope exchange (IE) and extended X-ray absorption fine structure (EXAFS) will be employed to determine: (1) dynamics of Zn and Cd partitioning between solid-solution,rhizosphere and non-rhizosphere, and in soil solution during repeated phytoextration; (2) physiological mechanisms on dynamic plant uptake during the depletion of bioavailable metal in rhizosphere; (3) rhizosphere mechanisms on the enhancement of metal bioavailability and plant uptake by different approaches. The main purpose of this project is to illuminate the mechanisms involved in the dynamic of Zn/Cd depletion and enhancements countermeasures based on the changes of heavy metal fractions, partitioning, activation and uptake during repeated phytoextraction, and to provide implications for long term remediation strategies especially after repeated cropping.

英文关键词： phytoremediation；heavy metal；bioavailability；soil-root interface；Sedum plumbizincicola