Cryopreservation of Panax ginseng Adventitious Roots

We tested desiccation and/or vitrification procedures to cryopreserve the adventitious roots of Panax ginseng, the source of commercially produced ginsenosides. When only desiccation was applied, the post-freeze survival of 3- to 4-mm root tips was <14% regardless of the composition of the preculture medium or the explant origin. Callus formation was frequently observed after cryopreservation. In contrast, 90% survival and 32.5% root formation efficiency were achieved after cryopreservation when a vitrification protocol was followed. Adventitious root cultures in flasks and bioreactors were reestablished from root tips cryopreserved by vitrification. A prolonged lag-phase and lower biomass production were recorded in post-freeze-regenerated cultures compared with control roots that were subcultured four times in flasks. However, biomass accumulations did not differ between control and regenerated roots at the end of the sixth subculturing period. After 40 days of culture in bioreactors, a mean value of 12.5 g dw L⁻¹ was recorded for post-freeze-regenerated cultures versus 9.1 g dw L⁻¹ for the control roots. Production of triol and diol ginsenosides in our bioreactor cultures also was enhanced after cryopreservation, by 41.0% and 89.8%, respectively. These results suggest that the vitrification method is successful for cryopreservation of P. ginseng adventitious roots.