Demethylation of methylmercury in growing rice plants: An evidence of self-detoxification. (March 2016) - Xu, Xiaohan
Abstract: Mercury (Hg) is a global pollutant that poses a serious threat to human and the environment. Rice was found as an important source for human exposure to Hg in some areas. In this study, the transportation and transformation of IHg and MeHg in rice plants exposed to IHg or MeHg were investigated. The IHg and MeHg concentrations in rice roots and shoots collected every five days were analyzed by HPLC-ICP-MS and SR-XANES. When exposed to MeHg, the percent of IHg in rice roots and shoots increased while MeHg decreased significantly, suggesting prominent demethylation of MeHg occurred. However no notable MeHg was found in both roots and shoots of rice plant when exposed to IHg. SR-XANES analysis further confirmed the demethylation of MeHg with rice. This study provides a new finding that demethylation of MeHg could occur in growing rice, which may be a self-defense process of rice plant. Graphical abstract: Inorganic mercury in Rice ( Oryza sativa L. ) plants exposed to methylmercury was detected: An evidence of rice plant against methylmercury phytotoxicity. Highlights: Demethylation of MeHg in rice plant was found in rice root. Hg in rice roots mainly present as MeHg-SR or RS-Hg-SR form. MeHg-SR in roots can be gradually transformed to RS-Hg-SR with rice growth. Abstract : Demethylation of MeHg in growing rice.