Juice vesicle explants of satsuma mandarin cultured on MS solid medium grew expansively and their weight increased 250-400% over a month and accumulated sugar (50-90 mg/g juice). However, sugar accumulation did not occur when one-third of fruit was cultured. Sugar accumulation only occurred in the juice vesicle explants excised from fruitlet later than 51 days after full bloom and cultured on a medium containing 10% sucrose. Supplements of benzyladenine (BA), gibberellic acid (GA3) or naphthalene acetic acid (NAA) in the medium promoted the growth of juice vesicles, but these growth regulators did not stimulate sugar accumulation. Effects of sucrose, glucose and fructose on vesicle growth and sugar accumulation were determined. Fructose was not effective for vesicle growth. Total sugar content in juice vesicles was highest on the medium containing glucose. Sugar composition in vesicles cultured on various carbohydrates indicated that sugar degradation and conversion occurred in vesicle explants. (C) 2001 Elsevier Science B.V. All rights reserved.