Compartmentation of Alternative Oxidase in Plant Mitochondria

Abstract

Capacity of alternative pathway mediated, CN-resistant respiration was measured in mitochondria isolated from three plant species: Iris bulbs, potato tuber callus and Petunia cells, grown in suspension culture. Succinate, NADH or a combination of succinate and NADH were used as respiratory substrates. In all three plant species electrons from exogenous NADH appeared to have no access to the alternative pathway connected with succinate mediated respiration and vice versa. Therefore, besides a (functional) compartmentation of Q-pools a compartmentation of alternative pathways in plant mitochondria is proposed as well.