土壌水分制限が大果系トマトのビタミンＣ，糖，有機酸，アミノ酸およびカロチン含量に与える影響

Abstract

The effect of soil water deficit on vitamin C, sugar, organic acid, amino acids and carotene contents in fruits of five large-fruited tomato cultivars was examined. 1. The effect of soil water deficit on vitamin C content per fresh weight varied, depending on the cultivars; in some cultivars vitamin C content increased, whereas in others it was unaffected. 2. The amounts of glucose and fructose per fresh weight in water-stressed plants were larger than those of control treatment in almost all cultivars, but they were the same on dry weight basis. This indicates that the soil water deficit merely reduced water accumulation by the fruits. 3. The amounts of organic acid and free amino acid (per fresh and dry weights) were increased by water deficit treatment. Furthermore, the effect of the treatment on the composition of organic and free amino acids was different which suggests that soil water deficit affects the metabolic pathway of organic and free amino acids in tomato fruits. 4. In red and pink type cultivars, soil water deficit tended to increase the amount of lycopene per fresh weight in the outer pericarp region but it had no effect on the amount and distribution of the yellow pigments, β-carotene and xanthophyll.