Ministry of Agriculture Key Laboratory of Non-point Source Pollution Control, Hangzhou, China.
J Sci Food Agric. 2010 Jul;90(9):1501-7. doi: 10.1002/jsfa.3974.
There has been increasing concern in recent years about the concentration of lead (Pb) in tea. However, little research has been done to address questions concerning the distribution of Pb in different varieties of tea plant and the differences among tea plant varieties in their uptake and accumulation of Pb from the soil. Therefore the aim of this study was to investigate the accumulation of Pb in different tea plant varieties and the factors affecting Pb bioavailability.
Three patterns of Pb distribution could be observed in different plant parts among the eight tea varieties surveyed, as well as a linear relationship between the Pb concentration in fine roots and the exchangeable Pb fraction in the corresponding soil. The uptake of Pb by fine roots increased significantly as the soil pH decreased. The average ratios of Pb concentration in fine roots to those in young stems and young leaves were 5.18 and 31.80 respectively. In fine roots the Pb concentration varied from 22.7 to 61.6 mg kg(-1).
The results indicated that the uptake, transport and accumulation of Pb by tea plant organs were strongly governed by soil conditions and tea variety, thus providing tea producers with useful information on variety selection for the production of quality teas containing low levels of Pb.
近年来，人们越来越关注茶叶中铅（Pb）的浓度。然而，对于不同品种茶树中 Pb 的分布以及茶树从土壤中吸收和积累 Pb 的能力差异等问题，研究甚少。因此，本研究旨在调查不同茶树品种对 Pb 的积累情况以及影响 Pb 生物利用度的因素。
在所调查的 8 个茶树品种中，不同植物部位的 Pb 分布呈现出 3 种模式，且细根中的 Pb 浓度与相应土壤中的可交换态 Pb 分数之间呈线性关系。随着土壤 pH 值的降低，细根对 Pb 的吸收显著增加。细根中 Pb 浓度与幼茎和嫩叶中 Pb 浓度的比值分别为 5.18 和 31.80。细根中的 Pb 浓度范围为 22.7 至 61.6 mg/kg。
结果表明，茶树器官对 Pb 的吸收、转运和积累受土壤条件和茶树品种的强烈影响，从而为生产者提供了有价值的信息，以便在生产低 Pb 含量优质茶叶时进行品种选择。
