期刊
PLANT PHYSIOLOGY
卷 134, 期 2, 页码 716-725出版社
AMER SOC PLANT BIOLOGISTS
DOI: 10.1104/pp.103.031948
关键词
-
Vacuolar compartmentalization or cell wall binding in leaves could play a major role in hyperaccumulation of heavy metals. However, little is known about the physiology of intracellular cadmium (Cd) sequestration in plants. We investigated the role of the leaf cells in allocating metal in hyperaccumulating plants by measuring short-term Cd-109 and Zn-65 uptake in mesophyll protoplasts of Thlaspi caerulescens Ganges and Arabidopsis halleri, both hyperaccumulators of zinc (Zn) and Cd, and T. caeridescens Prayon, accumulating Cd at a lower degree. The effects of low temperature, several divalent cations, and pre-exposure of the plants to metals were investigated. There was no significant difference between the Michaelis-Menten kinetic constants of the three plants. It indicates that differences in metal uptake cannot be explained by different constitutive transport capacities at the leaf protoplast level and that plasma and vacuole membranes of mesophyll cells are not responsible for the differences observed in heavy metal allocation. This suggests the existence of regulation mechanisms before the plasma membrane of leaf mesophyll protoplasts. However pre-exposure of the plants to Cd induced an increase in Cd accumulation in protoplasts of Ganges, whereas it decreased Cd accumulation in A. halleri protoplasts, indicating that Cd-permeable transport proteins are differentially regulated. The experiment with competitors has shown that probably more than one single transport system is carrying Cd in parallel into the cell and that in T. caerulescens Prayon, Cd could be transported by a Zn and Ca pathway, whereas in Ganges, Cd could be transported mainly by other pathways.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据