Ion Absorption and Retention by Chlorella Pyrenoidosa. II. Permeability of the Cell to Sodium and Rubidium

Abstract

Self diffusion of radioisotopes was used to estimate the permeability of Chlorella pyrenoidosa to Rb and Na. Isotope exchange in absence of net ionic movements followed first order kinetics. Na fluxes were found to be approximately 7 times larger than Rb fluxes. When compared with air-light isotope exchange of Na and Rb was drastically reduced by dark-nitrogen or dark-air. These changes in flux rates were explained mainly on the basis of metabolically dependent changes in the structure of the cell surface layers. Net cation accumulation and isotope self diffusion responded differently to metabolic inhibition, suggesting that cell permeability and ion retention may be 2 different metabolically controlled cell processes.