土壤-植物体系稀土元素的分异现象

Fractionation of Rare Earth Elements in Plant-Soil System

用仪器中子活化分析测定了从同一地点采集的 9种不同植物根和叶中 8个稀土元素 (La ,Ce ,Nd ,Sm ,Eu ,Tb ,Yb和Lu)的含量 ,研究了稀土元素在植物根、叶及相应母土中的分布特征。结果表明 ,同一植物的根、叶和母土中稀土分布模式均有较大差异。生长在同一地点不同植物根中稀土分布模式非常相似 ,而叶中分布模式差别较明显。说明根对单一稀土元素的吸收主要取决于这个元素在土壤中有效态的含量 。

The contents of eight rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in nine plant species collected from the same place were determined by instrumental neutron activation analysis. The distribution characteristics of REEs in plants and the corresponding soil were investigated. For a given plant, the REE patterns in roots, leaves and the host soil are different from each other. The REE patterns in various plant roots are very similar, but there are obvious differences between the leaves of different plants. It indicates that the REEs uptaken by plant roots are governed by the geochemistry of the host soil, but during the process of transportation and deposition into the plant leaves, the fractionations among different REEs are mainly caused by the plant themselves.