The accumulation of electrolytes in plant cells—a suggested mechanism

Abstract

The analysis of the sap of cells of plants such asValoniaNitellahas shown that the concentration of some of the ions is much greater in the sap than it is in the surrounding solution in which the cells have grown. Not only is this so for cations such as K but also for anions such as Cl. Höber and Höber (1928) found that the dilution of sea water with isotomic glucose caused practically no change in the potassium content ofValonia. Brooks (1929) added isotonic NaCl to sea water to such an extent that the concentration of potassium in the latter was reduced to a half, and yet there was no appreciable change in the composition of the cell sap ofValonia. To explain their results the Höbers postulated the existence of a membrane around the cell sap consisting of a mosaic of two kinds of areas: one positively charges and permeable to anions only and the other negatively charged and permeable to cations only. Brooks postulated a similar type of membrane to explain the accumulation of ions in the sap.