Abstract
To establish a physiological basis for storage and transport of the Chinese pear 'Yali', (Pyrus ussuriensis Maxim. var. sinensis Kikuchi), the occurrence of chilling injury and storage life of fruit stored at 0°, 5°, 10°, and 20°C were investigated. Inhibitory effects of temperature-conditioning prior to low temperature storage on chilling injury were also studied; the mechanism of conditioning-effect is discussed.
1. Browning and water-soaked appearance of flesh, which seemed to be symptoms of chilling injury, were observed in the fruit stored at 0° or 5°C, but not at 10° and 20°C. After an extended storage, browning of the core occurred at all temperatures, indicating to be a different symptom from that of chilling injury.
2. The rates of respiration and ethylene production in the fruit decreased with the lowering of storage temperature. The rates of respiration in the fruit transferred to 20° from 5°C recovered at the level of the fruit stored throughout the experiment at 20°C. However, respiration rates of fruit injured by the low temperature treatment and then transferred to 20°C were higher than that of the control.
3. The electrolyte leakage from flesh discs increased with the occurrence of chilling injury and continued to increase with the development of the injury symptoms.
4. The occurrence of chilling injury in fruits stored at 5°C was inhibited by various temperature-conditioning lasting more than three weeks. As stepwise cooling and delayed storage both inhibited the occurrence of chilling injury, the mechanisms of conditioning effects seem to depend on aging rather than on cold-acclimatization of the fruit.
5. The fruit stored at 5°C after an appropriate temperature-conditioning retained good eating quality even after 5 months of storage.
