title: Accumulation and translocation of 198Hg in four crop species.
abstract: The uptake and transport of mercury (Hg) through vegetation play an important role in the biogeochemical cycling of Hg. However, quantitative information regarding Hg translocation in plants is poorly understood. In the present study, Hg uptake, accumulation, and translocation in 4 crops-rice (Oryza.sativa L.), wheat (Triticum L.), corn (Zea mays L.), and oilseed rape (Brassica campestris L.)-grown in Hoagland solution were investigated using a stable isotope ((198)Hg) tracing technique. The distribution of (198)Hg in root, stem, and leaf after uptake was quantified, and the release of (198)Hg into the air from crop leaf was investigated. It was found that the concentration of Hg accumulated in the root, stem, and leaf of rice increased linearly with the spiked (198)Hg concentration. The uptake equilibrium constant was estimated to be 2.35 mol Hg/g dry weight in rice root per mol/L Hg remaining in the Hoagland solution. More than 94% of (198)Hg uptake was accumulated in the roots for all 4 crops examined. The translocation to stem and leaf was not significant because of the absence of Hg(2+) complexes that facilitate Hg transport in plants. The accumulated (198)Hg in stem and leaf was not released from the plant at air Hg(0) concentration ranging from 0 ng/m(3) to 10 ng/m(3). Transfer factor data analysis showed that Hg translocation from stems to leaves was more efficient than that from roots to stems.
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China; University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Liwei
authors.initials: L
authors.lastname: Cui
authors.forename: Xinbin
authors.initials: X
authors.lastname: Feng
authors.forename: Che-Jen
authors.initials: CJ
authors.lastname: Lin
authors.forename: Xinming
authors.initials: X
authors.lastname: Wang
authors.forename: Bo
authors.initials: B
authors.lastname: Meng
authors.forename: Xun
authors.initials: X
authors.lastname: Wang
authors.forename: Heng
authors.initials: H
authors.lastname: Wang
mesh_terms: D000393:Air Pollutants / Q000378:metabolism; D001937:Brassica / Q000378:metabolism*; D018527:Hydroponics; D008628:Mercury / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D018547:Plant Stems / Q000378:metabolism; D006109:Poaceae / Q000378:metabolism*; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D000393:Air Pollutants; D012989:Soil Pollutants; D008628:Mercury
keywords: Mercury; Plant uptake; Stable isotope; Transfer factor; Translocation