POSSIBILITY OF CONTROLLING FRUIT-CRACKING IN CHERRY TOMATOES BY LIGHTTREATMENT AT NIGHT

Control of fruit cracking in cherry tomato (Lycopersicon esculentum Mi ll.) 'Sun Cherry Extra' grown in hydroponics was attempted by light tr eatment during the night. The rate of fruit cracking in the untreated control was about 10%, whereas under a high light Intensity (81.1 mu m ol.s(-1).m(-2) PAR) and low light intensity (8.1 mu mol.s(-1).m(-2) PA R), it was 4 and 8.5%, respectively. Diffusive resistance of stomata a t 4 AM was 5 g.l(-1) under high light intensity: compared to 17 g.l(-1 ) in the untreated control. The rate of solute flow into the peduncle during the high light intensity treatment decreased to negative values , whereas thar into the petiole increased. This result indicates that solute flowed into the leaves when they were exposed to light. lowerin g the water potential to below that in the untreated control. Based on these results we conclude that the treatment with high light intensit y at night diminished the frequency of fruit cracking by decreasing th e solute flow into the fruit.