Changes in Adenosine Pyrophosphates in Cantaloupe Fruit Ripening Normally and after Treatment with Ethylene

During the climacteric rise in respiration of cantaloupe fruit (Cucumis melo L., var. reticulatus Naud.) the concentration per gramme fresh weight of adenosine triphosphate (ATP) increased and that of adenosine diphosphate (ADP) did not change; thus a net synthesis of adenosine pyrophosphate occurs during the respiratory climacteric. A net synthesis of protein which was observed was positively correlated with the concentration of ATP. Ethylene treatment stimulated a climacteric-like rise in the respiration and in the rate of ripening in fruit harvested at 9 to 32 days after anthesis. The ratio ATP/ADP increased in fruit ripened with ethylene only when harvested 20 days or more after anthesis.