INTERNAL CARBON DIOXIDE AND ETHYLENE LEVELS IN TOMATO FRUIT RIPENING ATTACHED TO OR DETACHED FROM THE PLANT

Abstract

The internal concentration of CO2 and C2H4 and the stage of ripeness was periodically measured in tomato fruit (Lycopersicon esculentum cv. Castelmart) attached to and detached from the plant. An external collection apparatus permitted nondestructive sampling of internal gases. The concentration of CO2 and C2H4 in the collection apparatus had equilibrated with the internal gas concentrations after 18 hr. A 20-fold increase in C2H4 during ripening of detached tomato fruit was paralleled by a 3-fold increase in CO2 concentration. Ripening attached fruit exhibited a 100-fold rise in C2H4 during ripening, but lacked a ripening associated climacteric rise in O02. CO2 did increase 2-fold in an erratic fashion during ripening of attached fruit, but the increase did not show any correspondence to increased C2H4 or ripening associated color changes. In tomato fruit, it appears that a CO2 climacteric per se, which has been considered an intrinsic quality of certain ripening fruit, may not be necessary for the ripening of “climacteric” fruit at all, but may instead be an artifact of using harvested fruit.