Growth, Morphogenesis and Cardenolide Formation in Long-term Cultures of Digitalis lanata¹

Abstract

The establishment of two different types of long-term cultures of Digitalis lanata is described. Characteristics of their development and conditions for triggering organogenetic processes are discussed. Radioimmunological analyses of these culteres revealed a) that a low level of cardenolides (about 1 ng/mg dry wt.) is always present and b) that in light-grown cultures a 10 - 100 fold increase is observed in media with low auxin activity which favours the formation of green globular structures and embryoids. Under suitable condition in suspension cultures cardenohde content reaches 1 mg/l culture within 20 days. The cardenolides formed are mainly digitoxigenin derivatives that are mostly retained in the cell material.