The effect of a controlled supply of nutrient solution on fruit quality of tomatoes grown in a rockwool culture system.

摘要

In tomatoes grown under a daily supply of 1.4 litres of nutrient solution in a rockwool culture system, soluble solids contents (SSC) were higher in cv. Momotaro than in cv. Kangyuck fruits. However, for both cultivars SSC contents were 1.0-1.4% higher in fruits cultivated under a limited supply (0.8 litres) of nutrient solution than those grown under normal supply (1.4 litres) conditions. Sugars that accumulated in the fruits were mostly glucose and fructose with trace amounts of sucrose. Sugar contents in fruits grown under the normal conditions increased gradually, but rapid increases were detected in those grown under the 0.8-litre system. Among the organic acids seen in fruits grown under normal solution supply, malic acid contents were about2% for both cultivars, while in fruits grown under the limited solution supply, levels were 2.5 and 3.0% in Momotaro and Kangyuck, respectively. Total organic acid contents were higher in tomatoes grown under the 0.8-litre supply than in those grown under the normal supply in both cultivars. Lower levels of NO3 were maintained in fruits grown under the limited supply as compared to fruits harvested from the 1.4-litre supply system. Total fruit yield was highest (683.8 g/plant) at the fourth fruit clusters (FC) of Kangyuck in the 1.4-litre system,while for the 0.8-litre system, the highest yield (565.5 g/plant) was at the second FC.