Chilling Exposures and Ethylene Treatment Change the Level of ACC in ‘Honey Dew’ Melons

Abstract

Abstract ‘Honey Dew’ melons (Cucumis melo L.) accumulated substantial amounts of ACC during a 2½-week chilling exposure at 2.5°C. The final concentration in chilled skin tissue was 15 nmol·g–1, which was about 70 times that in nonchilled skin tissue. The level of ACC in the underlying flesh also was increased by chilling, but to a lesser extent. The concentration of ACC decreased continuously during subsequent warming of the melons at 20° and had returned almost to the at-harvest level (<1 nmol·g–1) after 24 hr. Ethylene and CO2 production were low at 2.5° but rose rapidly during warming. A pre-chilling ethylene treatment (1000 µl·liter–1) for 18 hr at 20°) reduced chilling injury and ACC accumulation. ACC accumulation in the skin was negatively correlated with the presence of solar yellowing. Chemical names used: 1-aminocyclopropane-1-carboxylic acid (ACC).