CHANGES OF NON-STRUCTURAL CARBOHYDRATE IN LEAVES AND SHOOTS OF DIFFERENT PERSIMMON CULTVARS DURING PLANT DEVELOPMENT

The seasonal changes in the carbohydrate content in the leaves and shoots of ten persimmon genotypes grafted on Diospyros lotus were investigated throughout the “2009 and 2010” seasons. In the leaves, carbohydrate fractions decreased from April to June, then increased during fruit development until September and then reduced during autumn leaf-fall. Similar trends were found in fructose, glucose, sucrose and total sugar contents. Starch and total carbohydrate contents decreased in the leaves during the vegetative period and then increased from mid- and late summer to November. During the entire growing season, mean total sugar, starch and total carbohydrate contents in the leaves ranged from 5.89 (‘Vainiglia’) to 7.01% (‘Hachiya’), from 3.88 (‘Amankaki’) to 4.96% (‘Jirou’) and from 10.40 (‘Vainiglia’) to 11.66% (‘Jirou’), respectively. Sharp decreases in reducing sugar, soluble sugar and total carbohydrate content in the shoots occurred in April or after budbreak. These decreases continued until late summer, and then accumulation in the shoots began from September to December. There was a slow decline in the starch concentration during the vegetative growth phase from January to June, then increases occurred until the end of the year. During the whole year, the leaves contained more fructose, glucose, total sugar and starch contents than the shoots. Net photosynthetic rate of persimmon cultivars increased from April to September, and then decreased until leaf-fall. The net photosynthetic rate of different persimmon cultivars ranged from 5.35 (‘Amankaki’) to 6.40 µmol CO₂ m^-2 s^-1 (‘Eylül’) over the entire vegetation period.