Effects of Elevated CO2 Concentrations on the Ripening in Banana Fruit by Exogenous C2H4.

Abstract

Green bananas were treated with 0-60% CO2 and 1-100 p.p.m. C2H4 at 25°C for 24 h then transferred to air. CO2 treatment did not completely block the initiation of ripening by exogenous C2H4, but when the concentration of applied C2H4 was kept constant and the CO2 concentration high, the appearance of yellow pigment in the peel was delayed. The combination of various concentrations of CO2 and C2H4 on the respiratory climacteric in green fruits, monitored with an automated microcomputer system, revealed that the onset of the climacteric rise of fruits at any CO2 concentration combined with 1 p.p.m. C2H4 began at the same time as that of fruits kept in air and 1 p.p.m. C2H4. However, the progress of the climacteric rise was slower and the peaks were lower at high CO2 concentrations than they were at low CO2 concentrations. With 60% CO2 and 100 p.p.m. C2H4, fruits remained green until the end of the gas treatment, in spite of the slow respiratory rise and ripening of the flesh. The results suggest that elevated CO2 concentrations have no effect on the initiation of banana ripening induced by exogenous C2H4 but do reduce its rate.