川芎是重要的川产道地药材。川芎镉含量超标是制约其安全性和对外贸易的关键。降低川芎镉含量是亟待解决的问题。降低植物镉含量的方法中仅土壤钝化法是适用于川芎，可保障川芎药材道地性。而目前通过土壤钝化降低植物镉含量的机制尚待探明。. 申请者在对川芎及其根系土壤镉背景调查研究和氧化石墨烯材料研究基础上，设计合成了半胱氨酸氧化石墨烯（cys-GO）。该材料在溶液中对镉有优先吸附，理论上可与镉离子配位形成稳定六元环结构，是不易分解为离子态镉的稳定形态，具有钝化土壤镉的能力，在川芎盆栽预实验中有降低川芎根茎镉含量的效果。本研究拟通过探明半胱氨酸氧化石墨烯（cys-GO）在川芎根际土壤中与镉作用生成复合物（Cd-cys-GO）的结构，明确复合物（Cd-cys-GO）在土壤中的稳定性，阐明半胱氨酸氧化石墨烯（cys-GO）钝化土壤镉减少川芎镉含量的机制。为解决川芎镉超标问题提供新思路。

Ligusticum chuanxiong is an important genuine crude drugs in Sichuan. The problem of cadmium exceed the standard is the key to constrain its security and foreign trade. To reduce the cadmium content of Chuanxiong is an urgent problem to be solved. Among the methods for reducing cadmium content of plants, soil passivation is the only suitable method for chuanxiong for the capability to guarantee the genuineness of Ligusticum chuanxiong. At present, the mechanism of reducing the cadmium content in plants by soil passivation is still to be proved.. Cysteine-graphene oxide (cys-GO) is designed and synthesized based on the investigation of cadmium background of Chuanxiong and the rhizosphere soil and the study of graphite oxide. The material could passivate cadmium in soil in theory and produced the effect of reduction the cadmium content of Ligusticum chuanxiong Hort in the preliminary experiment in pot. This study aims to explore the structure of complex (Cd-cys-GO) generated in Chuanxiong rhizosphere soil and clarify the stability of complex (Cd-cys-GO) in the soil as to illustrate The mechanism of reducing the cadmium content of Ligusticum chuanxiong through passivating soil cadmium with cysteine-graphene oxide (cys-GO). Provide new thinking to solve the problem of chuanxiong cadmium exceed the standard.