How characean cells have contributed to the progress of plant membrane biophysics

Basic knowledge on plant membranes has been greatly indebted to internodal cells of charophytes, which are aquatic cryptogams mostly growing in fresh water and some in brackish water. The huge size of the internodal cell enab les us to study water and ion transport in a single cell. Furthermore, the cell can be subjected to various kinds of cell operations such as preparati on of cells having abnormal osmotic pressures, effusion of the steaming end oplasm, perfusion of the vacuole with artificial solutions, preparation of tonoplast-free cells and plasma membrane-permeabilised cells. Taking advant age of the large cell size and the cell operation techniques, various aspec ts of characterisations of plant membranes (plasma membrane, tonoplast, end omembranes) have been achieved using characean cells. The present article i ntends to depict unique contributions of characean cells to membrane physio logy and biophysics in the last century, focusing on several topics and wit h historical perspectives.