Die Wirkung hoher Salzkonzentration auf die Permeabilität der pflanzlichen Zellmembran

Using the device of Fig. 1 (this paper and 1. c. 3) efflux of Cl⊖ across the plasma membrane of root cortex cells was found to increase with increasing external concentration of various salts. We conclude that non-specific (passive) plasma membrane permeability (!) to anions increases with increasing external concentration of salts. As a primary result passive efflux of anions, which is downhill in the electrical gradient, increases.Efflux of Rb⊕ across the plasma membrane is only slightly stimulated by external KCl and is inhibited by Ca2⊕.The decrease in electrical potential with increasing external salt concentration is a consequence of the increase in passive plasma membrane permeability to anions.Interaction of salts with charged groups of the plasma membrane is not unlikely to be the reason for the increase of the permeability to anions and for the multiple hyperbolic influx isotherm observed at high external concentrations (1-100 mM). We want to emplasize that a multiple hyperbolic isotherm may be considered a feature of passive ion movement across a barrier of different charged groups.