Regulation of carbohydrate metabolism and compartmentation were studied during the acclimatization of tissue cultured Calathea plantlets. At transplantation plants were characterised by a heterotrophic metabolism with roots and stems as the main storage organs for carbohydrates. As acclimatization proceeded, a switch to autotrophic growth was observed: leaves became source organs, which was among others reflected by significant increases of invertase, sucrose synthase and sucrose-P synthase activities. Mobilization of reserves in roots and stems was also observed during the same period. Sucrose and starch accumulation in leaves was positively correlated with increasing light intensity.