ETHYLENE METABOLISM IN TOMATO FRUIT: I. RELATIONSHIP OF ETHYLENE EVOLUTION TO FRUIT RESPIRATION AND RIPENING

Ripening tomatoes were found to possess a climacteric peak in carbon dioxide production which was accompanied by evolution of ethylene. When the fruit was placed in oxygen, ripening and evolution of ethylene were accelerated in proportion to the increase in respiration. Peaks in carbon dioxide and ethylene evolution occurred not only when the fruit ripened, but also afterwards, during senescence. On the other hand, young, green fruit possessed a pronounced peak in carbon dioxide evolution without changes in color or texture or evolution of significant amounts of ethylene. Thus a series of waves in carbon dioxide production occurred as the tomato developed, ripened, and aged. Waves in ethylene evolution accompanied the carbon dioxide once the ripening process began. Evolution of large amounts of ethylene appeared to be associated with changes in the metabolic pathway that occurred with ripening, rather than being an accompaniment for increased respiration at any stage in the development of the fruit.