Respiration and C2H4 Production in Various Harvested Crops Held in CO2-enriched Atmospheres

Abstract

The respiration rate (O 2 uptake) and the rate of C 2 H 4 . production were measured before, during, and after 24 hours of treatment with 60% CO 2 (20% O 2 ) in 18 kinds of fruits and vegetables by use of an automated system connected to a microcomputer. High CO 2 decreased respiration only in climacteric fruit and broccoli, which were producing C 2 H 4 . Ethylene production decreased with CO, treatment of peaches, tomatoes, and broccoli, but that of bananas increased. In five nonclimacteric fruits (three citrus species, grapes, and Japanese pears) and several vegetables (carrots, onions, cauliflower, and cabbage), in which C 2 H 4 production was not detected, high CO 2 affected respiration little, if at all. When eggplants, cucumbers, podded peas, spinach, and lettuce were treated with high CO 2 , C 2 H 4 production began and respiration increased. These results indicate that the respiratory responses of harvested horticultural crops to high CO 2 might be mediated by the effects of CO 2 on the action and/or synthesis of C 2 H 4 .