Two modes of rubidium uptake in sunflower plants

Abstract

The Rb+-uptake kinetics in K+-starved sunflower (Helianthus annuus) plants can be explained by the addition of two Michaelis-Menten equations. In contrast, Rb+uptake can be described by a single Michaelis-Menten equation in normal-K+plants. Differences in the Kms and in the Arrhenius plots of Rb+ uptake in the two types of plants suggest two uptake modes.