Role of cell compartments in the redistribution of K and Na ions absorbed by the roots of intact barley plants

Abstract

Summary The redistribution of K and Na ions previously absorbed into the cytoplasm and vacuoles of roots of intact barley plants was studied. It appeared that all K ions, wether absorbed into the cytoplasm or into the vacuoles of the root cells, are transported to the shoots. For Na ions it holds that only the ions present in the cytoplasm are liable to upward translocation. The transport to the shoots of cytoplasmatic K ions can be enhanced by subsequent absorption of Na ions in the cytoplasm. The results of the present study suggest that cations present in the cytoplasm are adsorbed to or absorbed into cytoplasmic constituents. During redistribution, K ions move out of the vacuole at the same rate at which they move in. This suggests that the same mechanism is involved in movement across the tonoplast in both directions.