Changes in soluble carbohydrates and starch partitioning during vegetative bud formation from root tips of Catasetum fimbriatum (Orchidaceae)

Fluctuations in carbon partitioning were investigated during cellular expansion and induction of vegetative bud formation in cultures of isolated root tips of Catasetum fimbriatum, Orchidaceae. Root tip segments maintained on culture media supplemented with indolebutyric acid showed longitudinal growth accompanied by increased levels of glucose and fructose, despite the reduction in total soluble carbohydrate content. Induction of morphogenesis in the presence of zeatin was inversely related to cellular expansion which coincided with accumulation of soluble carbohydrates in the root segments. Vegetative buds had the highest levels of carbohydrates which decreased progressively during the development of plants. This suggests high carbon and energy costs for the production of new organs during growth and development. This revised version was published online in June 2006 with corrections to the Cover Date.