Chilling Sensitivity of Tomato Fruit in Relation to Ripening and Senescence

Abstract

Postchilling ion leakage, respiration, and C 2 H 4 biosynthesis were used to measure the degree of chilling injury to fruit of tomato ( Lycopersicon esculentum Mill. ‘Heinz 1350’). Chilling sensitivity, as measured by ion leakage, first declined as the tomatoes began to ripen and then increased during the late stages of ripening. Both C 2 H 4 biosynthesis and respiration rate were stimulated during the chilling response early in ripening. In the nonripening mutant, nor , chilling sensitivity did not show the early decline but showed the increase during senescence. Variation in chilling sensitivity during tomato ripening was biphasic, with a decline at the onset of ripening followed by a senescence-related increase. It is proposed that the latter may be due to an increase in membrane viscosity.