Characteristics of Respiration and Ethylene Production of Prune Fruit at Different Maturity Stages

Abstract

　To determine the ripening characteristics of prune (Prunus domestica L.) fruits, we investigated, using eight different prune cultivars, whether there was (I) an increase of respiration and ethylene production on trees at the mature stage (except in 'Puchull'), (II) an increase after picking from trees at the mature stage, and (III) autocatalytic ethylene production or a respiration increase in mature fruit after exogenous ethylene treatment. The respiration and ethylene production of fruit on trees were estimated from the respiration and ethylene production values determined for picked harvested fruits, which were kept at 20℃ for 24 hours before measurement. All cultivars showed a gradual decrease of estimated respiration on trees from the early immature to late immature stages, reaching their lowest respiration levels. Then, six cultivars (excepting 'Edwards'), exhibited a climacteric rise at the mature stage. Seasonal changes in internal ethylene concentration and estimated ethylene production on trees showed almost the same tendency tendency. Ethylene production on trees was low at the immature stage in all cultivars, and exhibited a climacteric rise at the mature stage in six cultivars (not includingexcept 'Edwards'). 'Stanley' and 'Valor' showed increases of both respiration and ethylene production after exposure to 500 ppm exogenous ethylene for 48 hours. From these results, 'Puchull' and 'Edwards' were categorized as suppressed-climacteric types, while the other six cultivars, 'Purple Ais', 'Blue Tan', 'Stanley', 'Valor', 'President' and 'Marjorie's Seedling', were categorized as climacteric types.