A Novel Approach for Predicting the Uptake and Toxicity of Cu2+ and Arsenate Based on the Electrical Properties of Root Cell Membrane
Electrical properties of plant cell membranes (CMs) play significant roles in the distribution of ions at the exterior surface of CMs (CMSe),the transport of ions across CMs,and hence the biotic effects of ions.The effects of major cations on the uptake and acute toxicity of Cu2+ and As (Ⅴ) to wheat (Triticum aestivum) were studied in terms of the electrical properties of CMs.Increases in Ca2+ or Mg2+ concentrations or decreases in pH in root bathing media reduced the negativity at the CMSe (ψ(°)(0)) with negligible effects upon the bulk phase-to-bulk phase transmembrane potential difference (Em).This reduction caused decreases in the activities of Cu2 + at the CMSe and increases in the activities of As (Ⅴ).The reduced surface negativity increased the surface-to-surface transmembrane potential difference (Em,surf),thus increase the electrical driving force for cation transport and decrease the driving force for anion transport across the CM.The balance of these two effects (altered surface-to-surface transmembrane activity gradients and electrical gradients) reduced Cu2 + uptake and toxicity and had the opposite effects upon As (Ⅴ).Regression analysis of measured uptake in empirical uptake equations provided evidence that uptake of ions is a function of both CM surface activities and Em,surf,independent of Em.This study provides novel insights into understanding the mechanisms of plant-ion interactions and extends current theory to predict the uptake and toxicity of metals and metalloids.
Cell Surface Electrical Potential Copper Arsenate Toxicity Uptake
Peng WANG Dong-mei ZHOU
State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,P.R.China
国际会议
The 2nd China-Japan Graduate Student Forum -- Life, Environment and Energy (第二届中日研究生论坛--生命,环境与能源)
北京
英文
80-87
2009-09-24（万方平台首次上网日期，不代表论文的发表时间）