ABSORPTION AND ACCUMULATION OF RUBIDIUM BROMIDE BY BARLEY PLANTS. LOCALIZATION IN THE ROOT OF CATION ACCUMULATION AND OF TRANSFER TO THE SHOOT

Abstract
Spectro-scopic methods were used in determining the longitudinal distribution of Rb and K in barley roots. A gradation in accumulation of these ions was demonstrated, the greatest conc. being at the apex. When the shoot removes Rb and bromide from the root, it does so first from the younger segments. Eventually ions, especially bromide ions, may be withdrawn even from levels at which the endodermis should be impermeable. During this process the normal gradient of salt accumulation may be reversed. Bromide moves to the shoot more readily than Rb.