COMPARISON OF COMPARTMENTAL ANALYSIS FOR RB+ AND NA+ IN LOW-SALT AND HIGH-SALT BARLEY ROOTS

The size of the cytoplasmic pools of Rb+ and Na+ in roots of barley (Hordeum vulgare L.) was estimated by two independent methods: . from the time curves of net Rb+ and Na+ uptake in low‐salt roots; . from the kinetics of ion exchange in Rb+‐and Na+‐saturated roots. The results indicate that in low‐salt roots there is a lag‐phase in vacuolar accumulation of Rb+ but probably not of Na+. At the same time part of the cytoplasmic Na+ pool seems to be excluded from rapid exchange. Both for Rb+ and Na+, flux reduction in saturated tissue appears to be more pronounced at the tonoplast than at the plasmalemma. Copyright © 1979, Wiley Blackwell. All rights reserved