Mechanism of sulfate uptake by excised maize roots

Abstract
The mechanism of uptake of sulfate by excised maize roots (Zea mays L. cv. Ganga-5) was investigated. It was found that in the concentration range l × 10−9 M − 5 × 10−2 M, the sulfate uptake could be represented by a single multiphasic isotherm having four phases. Each phase covered a limited concentration range and obeyed Michaelis-Menten kinetics, which indicates mediation in sulfate uptake by a structure which changes characteristics (kinetic constants) at certain discrete salts concentrations (transition points).