The Electric Resistance of the Cell Membranes in a Chara and a Nitella Species

Abstract

Experiments with microelectrodes are described which demonstrate that the plasmalemma (outer cytoplasmic membrane) is responsible for most of the direct current resistance in cells of Nitella. Further experiments show that the microelectrode method gives reliable measurements of the membrane resistance in such cells. The resistance of the plasmalemma, in the young N itella cells used, and in various media, ranged from 5 to 50 k.Q em", while the resistance of the tonoplast was less than 3 k.Q em". The combined membrane resistance of the mature Ohara cells used ranged from 10 to 30 k.Q em" with a mean value of 15 k.Q em", the cells being bathed in 1 ruN NaCI solution.