Changes in ethylene and CO2 during the ripening of apples

Abstract The internal concentrations and production of both ethylene and CO2 were measured during the maturation and ripening of Cox's Orange Pippin apples. Within 12 hours of the onset of the respiration climacteric there was no measurable increase in the production of ethylene and the data indicate that the increase in ethylene production is synchronous with the increased CO2 production that marks the start of ripening. It therefore appears that a factor other than a change in the rate of ethylene production determines the time at which apples commence ripening.