Selenium in soil inhibits mercury uptake and translocation in rice (Oryza sativa L.).
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.
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China.
Hua
H
Zhang
Xinbin
X
Feng
Jianming
J
Zhu
Atindra
A
Sapkota
Bo
B
Meng
Heng
H
Yao
Haibo
H
Qin
Thorjørn
T
Larssen
D004784:Environmental Monitoring; D008628:Mercury / Q000032:analysis / Q000378:metabolism*; D008767:Methylmercury Compounds / Q000032:analysis / Q000378:metabolism*; D012275:Oryza / Q000378:metabolism*; D018514:Plant Structures / Q000378:metabolism; D012643:Selenium / Q000032:analysis / Q000378:metabolism*; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*
D008767:Methylmercury Compounds; D012987:Soil; D012989:Soil Pollutants; D008628:Mercury; D012643:Selenium