Ethylene production in relation to the initiation of respiratory climacteric in fruit

Respiration of cherimoya fruit shows two peaks of CO2 production. The IEC is less than 0.05 ppm until the midpoint of the first respiratory rise. The fruit softens, develops pleasant aroma and flavor, and is considered ripe at the beginning of the second respiratory rise. Ripening and CO2 production in cherimoya and avocado fruit are initiated with no increase of internal ethylene and at ethylene levels which do not normally induce ripening in fruit. The ratio of the internal concentration of ethylene to its production rate varied with the stage of the climacteric and was less than one except for the very early stage in cherimoyas.