STAGES OF OZONE DAMAGE TO RESPIRATION OF TOBACCO LEAVES

Abstract

Two stages of damage were observed in the respiration of tobacco leaf tissues after fumigation with ozone. A damaging dose of ozone initially inhibited the respiration of fumigated leaves and of mitochondria removed from them.Stimulation of leaf respiration occurred later together with visible signs of damage and inhibition of photosynthesis. Mitochondria prepared from such visibly damaged tissue also showed stimulated activity. However, their cytochrome oxidase activity was inhibited and their oxidative phosphorylation was suppressed, like known effects of cyanide and carbon monoxide.