稀土元素在土壤-植物系统中行为与归宿的研究

Research Advances in the Behavior and Fate of Rare Earth Elements in Soil-plant Systems

对当前农用稀土安全性评价研究前沿的土壤-植物系统中稀土元素的行为与归宿研究予以综述。归纳出土壤pH、氧化还原电位、有机质、阳离子交换量、粘粒矿物等均影响外源稀土在土壤中吸附性能和迁移性、稀土元素各形态转化与可给性,植株或农作物体内聚集稀土元素的能力依赖于植物种类、土壤介质中稀土含量以及成土母质和相应的生境。与土壤介质相比,植株中单一稀土元素含量可存在一定的分异性,并且植株对单一稀土元素的吸收与运移具有选择性。为此有必要从细胞水平和分子水平进一步研究单一稀土元素在植物体内的存在状态和运移特性,同时深入研究稀土肥料的不同方式施用后,田间状况下农作物体内稀土元素的吸收及运移情况,特别是籽实中稀土元素的累积。

The behavior and fate of rare earth elements in soilplant systems is a hot spot in the field of safety assessment for agricultural use of rare earths.This paper gives a brief review about the behavior and fate of extrinsic rare earths in soil-plant systems.It has been shown that the absorption and translocation,as well as transformation and biological availability of added rare earths varies with some soil properties such as soil pH,oxidation-reduction potentials,organic matter contents,contents of exchangeable cations and clay minerals.The accumulation potentials of the rare earths in plants(crops) depend on plant varieties,contents of rare earths in soil as well soil origin and its biota.There is a separation of rare earths concentrations in plants compared to those in soil media,suggesting a selective uptake and translocation of individual rare earth in plants.It isnecessary to study on a molecular level the form and translocation of rare earths in plant cells and to study widely the accumulation and translocation of the rare earths in field-grown crops after application of rare earths-containing fertilizers,particularlyin the grain.