CHABGES IN ETHYLENE PRODUCTION AND 1-AMINO-CYCLOPROPANE-1-CARBOXYLIC ACID LEVELS IN CLIMACTERIC APPLE FRUITS(RALLS)UNDER LOW O_2 AND HIGH CO_2
Li Zhen-guo;Liu Yu;Xu Rong-jiang;Gu Wen-mao;Zhuang Shen-Jiang;Gao Jin-cheng Shanghai Institute of Plant Physiology, Academia Sinica Shanghai Fruit Company
Ethylene production was severely inhibited in climacteric apple fruits treated with either low O_2(O_2:1--3%, CO_2: 0%) or high CO_2(O_2,:15--21%,CO_2: 10--20%) for 4, 10, and 15 days, respectively. In treatment with low O_2 for 10 or 15 days, 1-aminocyclopropane-1-carboxylic acid (ACC) was accumulated in large quantity, but in the fruit treated with high CO_2, the content of ACC was slightly lower than that in control fruit. When the fruit was turned to air after 4-days treatment with low O_2, ethylene pro- duction and ACC content were able to recover to control level. But in the fruits with low O_2 for 10 or 15 days ethylene production was 100 times lower, and ACC content was much higher than those in control even 30--35 days after they were turned to air. It appears that inhibitory effect of the low O_2 treatment for longer than 10 days on the conversion of ACC to ethylene was irreversible. In the case of high CO_2 treatment for different periods ethylene production obviously decreased at first, then followed by a rapid increase. When the fruits were turned to air, ethylene production in the treat- ment for 4 days was able to recover to control level, but it remained much lower in tre- atment for 10 or 15 days than that in control throughout the period of recovery. Ho- wever, ACC contents in both treatments were slightly lower than those in control du- ring a few days after the removal of treatment, but increased slightly after 2--3 weeks. Furthermore, the ability of flesh discs to convert exogenous ACC to ethylene was redu- ced remarkably by the treatment of fruits with either low O_2 or high CO_2 for longer than 10 days.