Effect of Ethylene and Certain Metabolic Gases upon Respiration and Ripening of Pears before and after Cold Storage.

Previous work by the writers (6) has shown that the ripening rate of newly picked pears can be markedly stimulated by ethylene or gases of similar properties naturally evolved, but fruit treated after being held for prolonged periods of cold storage is not similarly affected. As a tentative explanation of these differences, it was suggested that the effects of ethylene are confined to a pre-ripening period, and later ripening changes apparently are unaffected by the presence of the gas in the atmosphere surrounding the fruit. These observations are in agreement with those previously reported by KIDD and WEST (1) for apples. The present investigation was undertaken to further study the effects of naturally occurring ethylene upon the. ripening processes in pears and to more definitely determine if there is a stage in the life of the fruit when treatment with this gas is most effective.