Studies on the interaction of growth regulators with potassium ions in some physiological processes in the bean (Phaseolus vulguris L.). II. The effect of potassium on growth of bean leaves and on their potassium and hormone levels

Abstract

The subject of study was the effect of K on the growth of primary and trifoliate leaves of the bean and on their potassium and hormone levels. Bean seedlings were grown in Hoagland's water solution in which the potassium concentrations (K –NO₃,) were 1 and 3 mM. The increase in the amount of potassium in bean leaves. elicited by increased K concentration in the medium or by partial defoliation. was correlated with a stimulation of growth of these organs and an increase in their H₂O content. These effects were connected with an increase in the amount of ABA and bound GA and decrease in the amount of auxins. The effect of potassium on the level of free gibberellins and cytokinins depended on the kind of leaves. In young, i.e. trifoliate leaves_ K was found to have a positive effect on the level of free GA, whereas in older. i.e. primary leaves, this effect concerned the level of cytokinins.