CINCHONA LEDGERIANA Moens et Trimen leaf-shoot organ cultures established and maintained on Murashige and Skoog's medium containing benzyladenine (BA 5 mg/l) were used to study the effects of age and growth regulators on alkaloid production. The total and individual alkaloid content of the leaf-shoot organ cultures increased with age and resembled closely that of the 1-year-old plant which favored quinine production. The 32-week-old tissue cultures contained the same amount of alkaloid as that of the 1-year-old plant (350 mg%). Quinine production was favored by the presence of benzyladenine (5 mg/l), gibberellic acid (5 mg/l) and/or shoots. Quinidine production was high in the presence of indole-3-acetic acid (5 mg/l), the absence of benzyladenine, and/or the presence of roots. High concentrations of abscisic acid and mefluidide inhibited growth and alkaloid production.

The alkaloid contents of the serially propagated CINCHONA LEDGERIANA leaf-shoot organ cultures that were fed with various precursors, were compared to the control cultures that were grown in Murashige and Skoog's medium supplemented with 5 mg/l benzyladenine. the average total alkaloid content of the 8-week-old leaf-shoot cultures increased approximately 66% with tryptopnan; 42% with secologanin; 5% with strictosidine-type, and decreased 10% with methoxystrictosidine-type alkaloid intermediates. The radioactive precursors: L-[3'- (14)C]-tryptophan was incorporated into cinchonidine (0.04%), cinchonine (0.01%), quinidine (0.01%), and quinine (0.08%); [5- (14)C]-10-strictosidine-HCl was incorporated into cinchonidine (0.01%), cinchonine (0.003%), quinidine (0.003%), and quinine (0.005%); and [5- (14)C]-10-methoxystrictosidine.HCl was incorporated equally (0.01%) into quinidine and quinine.