Effect of Auxin, Fusicoccin and Tris Buffer on Ion Uptake, Organic Acid Synthesis and Cell Elongation in Barley Coleoptile Segments

Abstract

The effects of auxin, fusicoccin and tris buffer on K⁺ and Cl^- uptake, total organic acids synthesis and cell elongation in barley coleoptile segments were tested. Some differences between the effects of fusicoccin and auxin on cell elongation and ion uptake were observed which support the idea that the two hormones may not be acting through a common mechanism. Tris buffer in the presence and absence of hormones stimulated K⁺ uptake and inhibited both Cl^- absorption and to some extent cell elongation. Tris buffer treatments, which resulted in excess K⁺ uptake over Cl^-, also caused a net synthesis of organic acids in the tissues. In some experiments, the relation between auxin-induced cell elongation and total organic acid synthesis was also examined.