PHYSIOLOGICAL-RESPONSES OF CHINESE PEAR Y ALI FRUIT TO CO2-ENRICHED AND OR O-2-REDUCED ATMOSPHERES/

Respiration and ethylene production rates of Chinese pear 'Yali' fruit (Pyrus ussuriensis Maxim. var. sinensis Kikuchi) stored in CO2-enrich ed and/or O-2-reduced atmospheres. In addition, several types of polye thylene film packaging were also applied to the long-term storage of ' Yali' fruit. 1. Oxygen uptake and ethylene production in 'Yali' fruit at 20 degrees C decreased with increasing CO2 concentration up to 40%. Ethylene production under 60% CO2 was markedly inhibited, whereas O-2 uptake was promoted; a physiological disorder in the flesh developed. 2. Under the same storage condition, oxygen uptake and ethylene produ ction consistently decreased with decreasing O-2 concentration. Howeve r, when O-2 was decreased to less than 5%, CO2 output exceeded O-2 upt ake, suggesting that anaerobic respiration was occurring. 3. Respirati on was inhibited in fruit kept at 10 or 20 degrees C under 5% CO2 + 3% O-2 during the first 4 days of storage and then increased suddenly th ereafter accompanied by the development of a physiological disorder. 4 . The storage life of the fruit packed in a film with soda lime at 10 degrees C, in which O-2 became to about 8%, was prolonged by about a m onth, as compared to that of those packed in a perforated bag. The gas concentration higher than 5% CO2 and/or lower than 5% O-2 within a pl astic bag caused an accumulation of ethanol and the development of dis order in flesh, thus shortening storage life of fruit. Our results sug gest that 'Yali' fruit is sensitive to both CO2-enriched and O-2-reduc ed atmospheres, and that 2% CO2 and 8% O-2 are about optimal for its l ong-term storage.