Evidence for a Plasmalemma Redox System in Sugarcane

Abstract
A plasmalemma-bound NADH-dependent redox system was identified in protoplasts isolated from cell suspensions of sugarcane. This system oxidized NADH as well as NADPH, increased O2 consumption 3-fold and increased the pH of the external medium while the cytoplasmic pH was decreased. In the presence of NADH, ferricyanide was rapidly reduced and the external medium was acidified. The uptake rates of K+, 3-O-methylglucose, leucine and arginine were all decreased in the presence of NADH.