Respiratory Response of Lemons to Ethylene1

Abstract

Abstract Green and yellow lemons responded to ethylene treatment by a 2- to 3-fold increase in O2 uptake. Maximum rates of O2 uptake were reached some 20 hr after treatment at 25°G and both O2 and the continued presence of ethylene were required. Following removal of ethylene, O2 uptake declined in 2 days to a level approaching the rate before treatment. Upon retreatment with ethylene, the fruits again responded with a 2- to 3-fold increase in O2 uptake. Ethylene stimulated the O2 uptake of lemons in 5% and 10% O2 even though the rates of O2 uptake of these fruits were already limited by the low levels of O2. The presence of high levels of CO2 during ethylene treatment did not suppress the ethylene-induced respiratory increase. Lemons treated with ethylene at 35°C showed typical increases in O2 uptake. 2-Chloroethanephosphonic acid (Ethrel) stimulated the O2 uptake of lemons more effectively than ethylene.