Effect of sodium humate on membrane potential in internodal cells of Nitellopsis obtusa

Abstract

Membrane potential and resistance changes in Nitellopsis obtusa induced by Na-humate as a function of external pH were investigated. The administration of Na-humate at concentrations of 12.5, 25, 50 and 100 mg dm-3 brought about a hyperpolarization of the membrane potential and a drop of d.c. resistance in the pH range between 4.0 and 9.0. Depolarization of the membrane potential induced by low pH was counteracted by Na-humate. The electrophysiological effects of Na-humate are compared with those of IAA.

Keywords

• humate
• membrane potential