茶苗对重金属Pb Cu Cd和Cr的吸收累积规律

通过盆栽实验,从动态角度研究了在不同培养期内,Pb、Cu、Cd和Cr4种重金属在茶树中的累积规律。结果表明,茶树不同部位对4种重金属的累积量存在很大差异,重金属的分布顺序为根〉茎〉叶;4种重金属大部分被茶树根系固定,在其体内的迁移性较低,在茶叶中积累的顺序为：Cr〉Cu〉Cd〉Pb。茶叶中重金属累积量和重金属添加量、培养时间都存在显著的正相关关系。4种重金属元素中,Cr的累积速率常数最大,Cd最小。茶树对重金属的吸收与土壤pH值和土壤有效态重金属含量显著相关。本研究可为人们科学认识茶叶中重金属的残留问题、健康风险及其污染控制提供理论依据。

Absorption and Accumulation of Cr,Pb, Cu and Cd in Young Tea Tree

The process of absorption and accumulation of heavy metals in tea tree was studied by potted cultivation in different culture period. The results showed that the absorption amounts of the four heavy metals （i.e. Pb, Cu, Cd, and Cr） were quite different in different parts of the young tea tree, and the sequence of all the four heavy metals were root〉stem〉leaf. The movement of the four heavy metals from soil into tea tree was low, most of them were fixed by root of the young tea tree, and the sequence of the four heavy metals in tea leaf was Cr〉Cu〉Cd〉 Pb. In addition, the accumulative amounts of the four heavy metals in tea leaf were related to the concentrations of the added four heavy metals in soil and culture time. The accumulative rate constant of Cr was maximum, while that of Cd is minimum among the four heavy metals. There were significant relationships between the absorption of heavy metals in tea tree and pH of the soil, and the amounts of available heavy metals in soil. This study can provide theoretical basis for recognizing heavy metals residue in tea, health risk and pollution control.