Regulation of Ethylene Production by Ripening Nectarine Fruit as Influenced by Ethylene and Low Temperature

Abstract

The rise in C 2 H 4 production during nectarine [ Prunus persica (L.) Batsch] fruit ripening at 20°C was accompanied by an increase in the level of 1-aminocyclo-propane-1-carboxylic acid (ACC) and ACC synthase activity. Activity of the C 2 H 4 -forming enzyme (EFE) also increased during ripening, but the level was at least 2-times greater than the C 2 H 4 production rate at all stages. C 2 H 4 treatment significantly increased C 2 H 4 production rate, ACC accumulation, and ACC synthase activity. Ability to convert ACC to C 2 H 4 , however, was reduced following C 2 H 4 treatment. An increase in total C 2 H 4 production at 20° following storage of nectarines at 0° for up to 4 days was attributable to enhanced ACC synthase activity. Exposure to C 2 H 4 at 0° for more than 4 days reduced C 2 H 4 production and EFE activity during ripening. Increased accumulation of ACC and lowered EFE activity following prolonged C 2 H 4 treatments at 0° suggests that C 2 H 4 production during ripening of fruit held under these conditions is limited by slowed conversion of ACC to C 2 H 4 .