Chilling at 0 deg C in air induces ethylene production in Fuji and Lady Williams apples

Abstract

Fuji apples have low rates of ethylene production at commercial harvest maturity, whereas Lady Williams apples, which are harvested commercially in late autumn, produce large concentrations of ethylene. We investigated whether chilling at 0¦C, which has previously been shown to stimulate ethylene synthesis in preclimacteric Granny Smith apples, would stimulate Fuji and Lady Williams fruit as well. Preclimacteric Fuji and Lady Williams apples were stored in air at 0¦C and were removed at intervals to 20¦C. Ethylene production remained low in Fuji apples held continuously in air at 20¦C. Fruit held for 32 days at 0¦C accumulated 1-aminocyclopropane-1-carboxylic acid (ACC) and developed ACC oxidase activity. On return to 20¦C these fruit had a high and sustained level of ethylene production. ACC accumulated in all chilled Lady Williams apples at 0¦C but decreased to low levels within 2 days after transfer to 20¦C. A sustained increase in ACC was not found until 15 days at 20¦C in fruit chilled for 32 days. A distinct temporary increase in internal carbon dioxide (CO2) concentration was observed in Fuji apples but not in Lady Williams apples following chilling. Chilling for 32 days was required to stimulate sustained levels of CO2 in Lady Williams apples.