The physiological basis of seed dormancy in Avena fatua. II. On the involvement of alternative respiration in the stimulation of germination by sodium azide

Abstract

Sodium azide, an inhibitor of cytochrome oxidase, has been shown to stimulate germination in several genetically pure lines of wild oats (Avena fatua L.). This effect of azide is completely inhibited by salicylhydroxamic acid, an inhibitor of alternative respiration. Sodium azide treatment, which induced germination, stimulated oxygen uptake by as much as 200 to 400%. The dose‐response curves for the stimulation of germination and of oxygen uptake by azide were very similar. The stimulation of oxygen uptake was completely inhibited by salicylhydroxamic acid and was not due to lipoxygenase activity. Thus, stimulation of salicylhydroxamic acid‐sensitive oxygen uptake (alternative respiration) is associated with and is necessary for the stimulation of germination in the presence of azide. However, it remains to be shown whether the induction of alternative respiration by azide is the direct cause of stimulation of germination.In the Montana 73, unlike other pure lines investigated, azide stimulated alternative respiration, but not germination. The lack of germination response in this line is considered to be due to an additional metabolic block in the processes leading to germination.