INFLUENCE OF THE NUTRIENT SOLUTION CONCENTRATIONS ON CRACKING OF CHERRY TOMATO FRUIT GROWN HYDROPONICALLY

We studied the influence of the nutrient solution concentrations on cr acking of cherry tomato fruit grown hydroponically and the mechanism o f cracking. 1. In 'Sugar Lump', 'Sun Cherry' and 'Mini Carol' the occu rrence of fruit cracking increased as the concentrations of the soluti ons became higher. However in 'Akakokko', the concentrations of the so lution had very little influence. 2. There were no differences in the cumulative temperatures (the number of hours above 0-degrees-C) from a nthesis to full ripeness or the number of fruits cracking among the fo ur cultivars. 3. It is postulated that the factors which promote fruit cracking are : 1) an increase in soluble solids content, 2) decrease in osmotic pressure of the pulp, 3) flesh firmness. 4. Less volume of injected water was required to induce fruit cracking artificially in f ruits harvested from the high nutrient solution concentration than fro m that of the low concentration. Fruits of 'Sun Cherry' seemingly impo rt water more easily because of a lower osmotic potential of the fruit flesh (PSI(flesh)), compared to that of the external solution (PSI(so lution)). In the water absorption test the occurrence of fruit crackin g and the rate of expansion of fruit volume increased when plants were grown in solutions of high concentration. These results indicate that frutis can absorb water rapidly under these conditions.