THE EFFECT OF TRANSPIRATION ON THE ACCUMULATION OF CARBOHYDRATES IN TOMATO FRUIT.

Abstract

Previous studies suggest that transpiration from fruit surface drives the inflow of phloem sap into fruits. In those studies, the increment of the size of fruits was restricted mechanically to avoid the effects of changes in fruit size on the import of water. In this experiment, the influence of transpiration on the accumulation of carbohydrates was investigated in intact tomato fruits. Tomato fruits. 7 days after flowering, as attached to the plants were enclosed in the chamber of low humidity (LH) or high humidity (HH) and they were sampled 38 days after flowering. The enlargement of LH fruits was smaller than that of HH fruits. The accumulation of dry matter and total sugars on a fruit basis was lower in LH fruits than in HH fruits. There was no difference in the content of dry matter between LH and HH fruits. The concentration of total sugars of LH fruits was slightly lower than that of HH fruits. Lower accumulation of carbohydrates in LH fruits shows that transpiration flow of phloem sap is not the predominant factor that controls the inflow of photosynthetic assimilates in intact tomato fruit.