Influence of sodium humate on the uptake or some ions by tomato seedlings

Abstract

The influence of sodium humate on the uptake of K+, Rb+ NH4+, Mg2+, Fe3+ PO43-, NO3- and Cl- ions from equilibrated aqueous solutions was investigated. By varying transpiration and applying dinitrophenol "passive" and "active" uptake were distinguished. Ion decrease in the solution and accumulation of labelled elements in roots and shoots were determined. Humate strongly stimulated K+ and Rb+ uptake and strongly inhibited the uptake of Cl-, while it slightly enhanced Mg+2 and PO43- uptake. It, moreover, facilitated iron transport from the roots to shoots. The interaction of humate with dinitrophenol is discussed.