Effect of phytohormones on absorption and distribution of ions in salt-stressed bean plants

Abstract

Bean plant seedlings grown in water culture were treated for 5 days either with NaCl or with 7-times concentrated nutrient solution (diminished water potential by 3-10³ hPa in both cases). Control and stressed plants were treated for 24 hrs with zeatin and GA,. NaCl-stress reduced distinctly ion absorption rate (K, Ca and P). Zeatin and GA₃ promoted potassium uptake, but only in NaCI-treated plants. These hormones diminished Na accumulation in metabolically active organs but increased P- and Ca-content. In plants grown under both kind of stresses zeatin and GA₃ partially reestablished the ratio of the main mono- to divalent cations, which increased in the leaves and apical part of the stressed plants. ABA introduced into the nutrient solution caused inhibition of the ion uptake (K, Ca, Mg and P). similar to that caused by NaCl-stress. The above reported results seem to confirm the supposition, that hormones act as an important factor contributing to regulation of both uptake and distribution of ions. In this way growth substances may also participate in the regulation of transport of various substances (among others - assimilates) in the whole plant.