Abstract
The changes in the volume of carbohydrates assimilated each month from summer (Aug.; 2 months after harvest) to late fall (Nov.; just before defoliation) in each organ of the Japanese apricot (Prunus mume Siebold & Zucc.) ‘Nanko’ tree were determined until May the following season. The 13C concentrations in the young fruits and new leaves were significantly low at the beginning of May. This phenomenon indicates that their growth depends on current instead of reserve carbohydrates. In May, carbohydrates assimilated in Aug., Sep., and Oct. were mainly transported to 2-year-old twigs (current twigs at 13C feeding time), roots, and trunk, respectively. Carbohydrates assimilated in Nov. were mainly transported to the flower buds with subsequent flowering at a significantly greater level, and barely transported to the perennial organs. These findings show that carbohydrates that are assimilated each month contribute to different organs and, particularly, that those assimilated in Nov. are important for the growth of flower buds and subsequent flowers; therefore, healthy leaves should be maintained until defoliation for stable production of the fruit of the Japanese apricot tree.
