JACOBY, B., Department of Agricultural Botany, Hebrew University, Rehovot, Israel
ABAS, S., Department of Agricultural Botany, Hebrew University, Rehovot, Israel
STEINITZ, B., Department of Agricultural Botany, Hebrew University, Rehovot, Israel

At salt concentrations of 0.1 mM as well as of 5.0 mM, the 22Na+ absorption capacity of bean (Phaseolus vulgaris L. cv. ‘Brittle Wax’) leaf tissue increased during the period of leaf expansion and decreased rapidly after leaf maturation. The absorption capacity for 86Rb+ and 42K+ was highest in very young leaves and decreased continuously in expanding and in mature leaves. The 86Rb+ absorption capacity of mature leaves was not increased by detopping the plants; this senescence‐retarding treatment more than doubled 2Na+ absorption. The absorption of 22Na+ by bean‐leaf slices was not enhanced by light, whereas 86Rb+ and 42K+ absorption was much affected. Previously absorbed 86Rb+ and 42K+ were more available for exchange than 22Na+. Copyright © 1973, Wiley Blackwell. All rights reserved