Cell suspension cultures of young leaves (L) and roots (R) of Bouvardia temifolia were cloned and their growth was followed, measuring cell volume and fresh weight. Both cultures were depleted of nitrogen and subcultured in different nitrogen sources. The enzymes for ammonium assimilation and the ammonium pools were measured during the growth cycle. Results indicate that the two ammonium assimilation pathways, the GS/GOGAT, and the GDH-GS, are functional in both cultures. The pathway used is dependent upon the tissue and the nitrogen source in the medium. GDH seems to have an anabolic role on root cultures and is regulated by the internal concentration of ammonium. Copyright © 1984 Gustav Fischer Verlag, Stuttgart. Published by Elsevier GmbH.. All rights reserved.