State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China.
Environ Sci Technol. 2012 Sep 18;46(18):10040-6. doi: 10.1021/es302245r. Epub 2012 Aug 30.
A great number of studies have confirmed that mercury-selenium (Hg-Se) antagonism is a widespread phenomenon in microorganisms, fish, poultry, humans, and other mammals. However, by comparison, little attention has been paid to plants. To investigate the influence of Se on the uptake and translocation of methylHg/inorganic Hg (MeHg/IHg) in the rice-soil system, we determined the levels of Se, IHg, and MeHg in different parts of rice plants (including the root, stem, leaf, husk, and grain (brown rice)) and corresponding soils of root zones collected from a Hg mined area, where Hg and Se co-occur due to historic Hg mining and retorting activities. The results showed that, in general, the Se levels were inversely related to the levels of both IHg and MeHg in the grains. In addition, a consistent reduction in translocation of both IHg and MeHg in the aerial shoots (i.e., the stem, leaf, husk, and grain) with increasing Se levels in the soils was observed. Furthermore, the Se levels were positively correlated with the IHg levels in the soils and the roots. These results suggest that Se may play an important role in limiting the bioaccessibility, absorption, and translocation/bioaccumulation of both IHg and MeHg in the aerial rice plant, which may be related to the formation of an Hg-Se insoluble complex in the rhizospheres and/or roots.
大量研究证实,汞-硒(Hg-Se)拮抗作用是微生物、鱼类、家禽、人类和其他哺乳动物中普遍存在的现象。然而,相比之下,人们对植物的关注较少。为了研究硒对水稻-土壤系统中甲基汞/无机汞(MeHg/IHg)的吸收和迁移的影响,我们测定了来自汞矿区的水稻植株不同部位(包括根、茎、叶、壳和糙米(籼米))和根区相应土壤中硒、IHg 和 MeHg 的水平,这些矿区由于历史上的汞矿开采和蒸馏活动而导致汞和硒共存。结果表明,一般来说,硒水平与籽粒中 IHg 和 MeHg 的水平呈负相关。此外,随着土壤中硒水平的升高,可观察到地上部分(即茎、叶、壳和糙米)中 IHg 和 MeHg 的迁移明显减少。此外,土壤和根中的硒水平与 IHg 水平呈正相关。这些结果表明,硒可能在限制地上水稻植株中 IHg 和 MeHg 的生物可利用性、吸收和迁移/生物累积方面发挥重要作用,这可能与根际和/或根部形成 Hg-Se 不溶性络合物有关。