盐肤木(Rhus chinensis Mill)根系分泌物对铅的活化、吸收机制研究

重金属污染是当今普遍存在并较为严重的环境问题之一，严重威胁着人类的健康,因此重金属污染问题亟待解决。植物在重金属胁迫中，根系是最先感知的器官，其中根系分泌物对植物吸收重金属影响很大。本项目根据前期已有的试验结果，研究土培下两种盐肤木在不同铅浓度处理下根系分泌物的成分和含量的差异性、植物组织中Pb含量和分布特征、土壤根际环境的变化特征以及土壤Pb形态变化，明确根系分泌物、根际环境、与Pb积累的关系，同时明确Pb活化机制。在此基础上通过质谱分析，并利用同步辐射X射线吸收光谱(XAS)技术和同步辐射X射线荧光谱(XRF)技术研究不同有机酸处理后Pb及其它元素在两种盐肤木根系组织的微区分布特征、Pb在亚细胞水平分布和吸收Pb化学结合形态的差异。明确Pb在根系中赋存形态，从而初步阐明盐肤木根系分泌物对Pb的吸收机制。

Heavy metal pollution is a widespread and important environmental concern. Phytoremediation is promising due to its low implementation costs and significant environmental benefits. Rhus chinensis Mill have been proposed both for stabilisation and removal of metals from contaminated soils as they are fast to propagate, achieve high annual biomass production and generally possess a high tolerance against metal pollution in our research. R. chinensis have different mechanisms of metal uptake from other woody species. Understanding the mechanisms of metal uptake and accumulation will provide insight into the enhance and improve capacity to remove heavy metal. In this study, we made a further probe into the mechanisms of Pb uptake and tolerance in R.chinensis plants, with the aim to reveal the variety differences in the Pb toxiceffect and Pb chemieal forms and subeellular distribution in Plant, the mechanism of Pb absorption, distribution and accumulation in different Plantorgans, and the role of root exudate in Pb accumulation and the micro distribution of both Pb and other elements in different Plant organs by μ-XRF and μ-XANES. According to the information on the coordination between metals and root exudate, in combination with the uptake capacity in root, the function of root exudate compounds in metal uptake would be predicted.