原位研究水稻根际微环境对重金属释放与生物有效性的影响机制

Increasing pollution of heavy metals induced more serious harm to human beings via food chains. Rice is an important exposure of heavy metals in China. So it is necessary to investigate the effect of micro-environment on the remobilization and bioavailability of metals. Iron plaques, micro-niches and macro-niches are the important factors controlling the metal release in the rhizosphere though there is not many reports on them due to limit of techniques. In this proposal a new in-situ high resolution method (DGT, Optode and Porewater Sampling Sandwich Sensor System; DOPS) will be developed based on the Diffusive Gradients in Thin-films (DGT), planar optode, and planar porewater sampler. The method can measure metals, pH, oxygen and other parameters simultaneously. Effect of iron plaques, micro-niches and macro-niches on the metals’ remobilization and bioavailability to rice will be investigated in detail. This research will help us to understand the mechanisms of metal behavior in soils and therefore to control the pollution.

工业化和城市化的快速推进导致我国农田重金属污染日益严重，使得农产品尤其是稻米遭受不同程度的重金属污染。为了阻控重金属从土壤向水稻的转移，因此有必要开展水稻根际微环境对重金属释放和生物有效性的影响研究。铁膜、微生境和宏生境是根际微环境的重要组成部分，然而由于技术原因，之前很少有报道采用原位高分辨手段研究它们的影响。本项目以水稻根际重金属（Cd、Pb、Ni、Cu、Fe、Mn等）为研究对象，拟融合DGT技术、平板光极技术和平板式网格化间隙水采样器开发一种新型二维高分辨率原位复合式传感器系统，研究水稻根际铁膜、土壤微生境、宏生境对根际重金属释放以及生物有效性的影响规律，阐述这三者与重金属释放和生物有效性间的微界面定量作用机制。为我国农田重金属的控制以及提高水稻安全性提供理论依据，具有社会意义和科学价值。

根据项目计划以水稻根际多种重金属为研究对象，开发一种能够同时测定土壤中有效态重金属、环境因素（pH和O2）以及其他影响因素的融合DGT技术、平板光极技术的新型二维高分辨率原位复合式传感器系统，研究了水稻根际铁膜、土壤微生境、宏生境对根际多种重金属释放的影响规律，揭示了这些具有更高化学活性的局部微观区域对水稻根系吸收重金属元素的贡献，阐述了这三者与重金属释放和生物有效性间的微界面定量作用机制。