Possibility of controlling fruit-cracking in cherry tomatoes by light treatment at night

Abstract

Control of fruit cracking in cherry tomato (Lycopersicon esculentum Mill.) 'Sun Cherry Extra' grown in hydroponics was attempted by light treatment during the night. The rate of fruit cracking in the untreated control was about 10%, whereas under a high light intensity (81.1 μmol · s-1 · m-2 PAR) and low light intensity (8.1 μmol · s-1 · m-2 PAR), it was 4 and 8.5%, respectively. Diffusive resistance of stomata at 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 that into the petiole increased. This result indicates that solute flowed into the leaves when they were exposed to light, lowering the water potential to below that in the untreated control. Based on these results we conclude that the treatment with high light intensity at night diminished the frequency of fruit cracking by decreasing the solute flow into the fruit.