稀土在土壤-植物系统中的分馏效应及影响因素  

Fractionation and Relevant Influencing Factors of Rare-Earth Elements (REEs) in a Soil-Plant System

作　　者：顾雪元[1] 王晓蓉[1] 顾志忙[1] 

机构地区：[1]南京大学环境学院污染控制与资源化国家重点实验室,南京210093

出　　处：《环境科学》2002年第6期74-78,共5页Environmental Science

基　　金：国家自然科学基金资助项目 (2 9890 2 80 1) ;江苏省自然科学基金资助项目 (BK990 34)

摘　　要：以稀土背景较高的红壤为供试土壤 ,采用小麦盆栽实验 ,研究了稀土元素在土壤 小麦系统中的分馏模式 ,考察了外源稀土浓度、腐殖酸浓度和土壤酸度对稀土分馏模式的影响 .结果发现 ,红壤中稀土的分馏模式与我国土壤的稀土分馏模式基本一致 ,为向右倾斜的轻稀土富集模式 .小麦根部的稀土分布模式与土壤类似 ,小麦茎叶中稀土分布模式则有所不同 .加入外源稀土后 ,小麦根部的稀土分馏模式随土壤中稀土丰度的改变而改变 ,而小麦茎叶中的稀土分馏模式却保持相对稳定 ,说明小麦地下部分与小麦地上部分对稀土的吸收方式存在差异 .腐殖酸对稀土在土壤 小麦系统中的分馏效应影响不大 .土壤酸度对稀土在土壤 小麦系统中的分馏效应有一定的影响 ,在所试验条件下 ,观察到小麦中稀土元素的分馏系数随pH值降低而降低 ,高 pH值 (pH =6 7)使稀土在小麦中的分馏系数加大 .A potted method was carried out in this paper to research fractionation and some influencing factors (including the concentrations of REEs,humic acids and pH of soil) of the REEs (La,Ce,Nd,Sm,Eu,Gd,Tb and Yb) in a soil\|plant system.The results showed that the fractionation model of REEs in red soil used in this experiment was similar to the average fractionation model of soil in China.The fractionation model of REEs in wheat root was similar to the model of the soil,but the fractionation model of REEs in wheat tops was not similar to that one.When REEs were added,the fractionation model of REEs in wheat root was changed similarly to that of the soil,but the model of wheat tops was kept constant.The results suggest the adsorbing way of REEs by wheat root and wheat tops were different.Humic acid showed little influence on the fractionation of REEs in wheat.High pH value (pH=6 7) promoted the adsorption of light REEs by wheat;whereas,low pH value (pH=4 2) promoted the adsorption of heavy REEs by wheat.

关 键 词：稀土 土壤 植物 分馏效应 影响因素 微量元素肥料 环境土壤 

分 类 号：X144[环境科学与工程—环境科学]