Seasonal Variations in The Amounts of Polyhydric Alcohol and Sugar in Fruit Trees

Abstract

Seasonal variations in the amounts of sugar and polyhydric alcohol in the twig bark or leaves of 12 species of fruit trees were measured at intervals during the period from summer to winter.In apple, plum, pear, peach and cherry trees, there was a considerable amount of polyhydric alcohol both in summer and in winter, the alcohol/sugar ratio being nearly 70% in summer and 43% to 73% in winter. In persimmon and grape there was only a small amount of polyhydric alcohol in summer; this increased considerably during the winter, to a ratio to sugar of about 50%. In citrus trees, the amount of polyhydric alcohol was very small even in winter.The kinds of sugar were almost the same in all of the species, although their proportions differed markedly with the species and with season in the same species. Fructose, glucose and sucrose were the major sugars in every species. Raffinose appeared first in the autumn and stachyose in the early winter, increasing rapidly toward midwinter.