Abstract
Calcium channels in the plasma membrane of root cells facilitate the movement of Ca2+ to the xylem, by providing a symplastic bypass to the Casparian band, and regulate cellular activities through changes in cytoplasmic Ca2+ concentration. In this paper, the biophysical properties and physiological functions of Ca2+ channels in the plasma membrane of root cells are reviewed. Acclimation to low temperatures is given as an example to illustrate how kinetic and permeation models can be used to understand the physiology of Ca2+ channels and to predict Ca2+ fluxes under physiological conditions.