Abstract
Using serpentine fluorescence as an indicator of alkaloid production in cultured Catharanthus roseus cells, 6 cell lines producing alkaloid in excess of 300 mg/l were selected from more than 2 × 105 individual colonies and their alkaloid production was monitored over a period of 8 years. Rapid loss of productivity invariably occurred during the first few months of cultivation, and spontaneous recovery of the initial production rates was never observed. Production of the indole alkaloid precursor, secologanin, followed the same pattern. Recovery of high alkaloid yielding strains was, however, possible at any time by repetition of the clonal selection procedure, but these strains were again instable. Clonal selection of high yielding plant cell strains apparently favours an inherent instability.
