Abstract
We studied the influence of the nutrient solution concentrations on cracking of cherry tomato fruit grown hydroponically and the mechanism of cracking.
1. In 'Sugar Lump', 'Sun Cherry' and 'Mini Carol' the occurrence of fruit cracking increased as the concentrations of the solutions became higher. However in 'Akakokko', the concentrations of the solution had very little influence.
2. There were no differences in the cumulative temperatures (the number of hours above 0°C) from anthesis to full ripeness or the number of fruits cracking among the four 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 fruits harvested from the high nutrient solution concentration than from that of the low concentration.
Fruits of 'Sun Cherry' seemingly import water more easily because of a lower osmotic potential of the fruit flesh (Ψflesh), compared to that of the external solution (Ψsolution). In the water absorption test the occurrence of fruit cracking 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.
