植物对稀土元素分馏作用研究——以玉米和豌豆为例

Study on the Fractionation of Rare Earth Elements by Plants:the Case of Maize and Pea

稀土元素在植物中会有明显的分馏现象,研究稀土在土壤-植物体系中的分馏情况对于认识稀土在土壤-植物系统中的迁移分布模式具有重要的意义。以玉米和豌豆两种植物为例,通过改变生长土壤pH、外源稀土含量,研究了玉米和豌豆对稀土元素的分馏作用,并分析了各变量条件下的稀土元素分馏情况。结果表明,稀土在玉米和豌豆及二者生长的土壤中的基本分布模式均为向右倾斜的轻稀土富集模式;玉米根茎叶随土壤中稀土元素浓度升高逐渐偏向对轻稀土的富集,而土壤中则相反;豌豆根茎叶对中等浓度的稀土偏向于重稀土的分馏,低浓度和高浓度稀土偏向于轻稀土的分馏,而其生长土壤正好相反。pH改变基本不会控制玉米和豌豆稀土元素的分馏富集情况,且在这两个因素影响下,玉米和豌豆及二者生长土壤均出现明显Eu负异常和Ce正异常。

Rare earth elements show significant fractionation in plants,and studying the fractionation of rare earths in the soil-plant system is important for understanding the migration distribution patterns of rare earths in the soil-plant system.In this paper,we studied the fractionation of rare earth elements in maize and pea as examples by changing the pH and exogenous rare earth content of growing soil,and analyzed the fractionation of rare earth elements under each variable condition.The results showed that the basic distribution pattern of rare earths in maize and pea and the soil in which they were grown was a right-sloping light rare earth enrichment pattern;maize rootstocks and leaves gradually favored the enrichment of light rare earths as the concentration of rare earth elements in the soil increased,while the opposite was true in the soil;pea rootstocks and leaves favored the fractionation of heavy rare earths for medium concentrations of rare earths,and light rare earths for low and high concentrations of rare earths,while the soil in which they were grown was the opposite.pH changes basically did not control the fractionation enrichment of rare earth elements in corn and pea.Under the influence of these two factors,both maize and pea and both growing soils showed significant negative Eu anomalies and positive Ce anomalies.