Towards a model for malate accumulation in plant tissues

Abstract

A partial model for the accumulation of potassium and malate in plant tissue is proposed on the basis of the kinetics of 14CO 2 uptake and release by roots in the presence and absence of potassium in the medium. In the presence of potassium, there is a greater amount of 14C from 14CO 2 accumulated in malate and other organic acids than in the absence of potassium. The decarboxylation of accumulated organic acids is slower in the presence of potassium than in its absence leading to the hypothesis that carboxylation is most likely independent of potassium, but decarboxylation is depressed in the presence of potassium because malate is in an inactive pool perhaps (in vacuoles) acting as a counter ion to potassium which also accumulates.