Figure 1.
Upper: Scavenging of nitric oxide by plant mitochondrial electron transport chain components when oxygen is present. In these conditions nitrate reductase produces NO and superoxide produced in mitochondria reacts with NO and forms peroxynitirte and also NO can easily react with oxygen to form gaseous intermediates like N2O3 and NO2. Lower: Reduction of nitrite to NO by the electron transport chain of plant mitochondria in hypoxic conditions. According to the inhibitory effects of myxothiazol and (complex III) and cyanide (IV) salicylhydroxamic acid (AOX), both terminal oxidases appear to possess nitrite: NO reducing activity.