Cell cultures of Panax ginseng and Catharanthus roseus producing secondary metabolites were preserved in liquid nitrogen or under mineral oil for six months. The growth behaviour and the ability of the cultures to produce ginsenosides or indole alkaloids were measured after a recovery period and compared with cultures maintained by frequent subcultivation during the same period. Neither growth kinetics nor the degree of vacuolization during growth were affected by the long term preservation. Some changes in secondary metabolism were however found, indicating that preservation under mineral oil does not preserve the productivity of cell cultures whereas the cryogenic method does.
Mannonen, L., Toivonen, L., & Kauppinen, V. (1990). Effects of long-term preservation on growth and productivity of Panax ginseng and Catharanthus roseus cell cultures. Plant Cell Reports, 9(4), 173-177. https://doi.org/10.1007/BF00232173