Cryopreservation of shoot apices of in-vitro grown gentian plants: comparison of vitrification and encapsulation-vitrification protocols.

Using vitrification and encapsulation-vitrification protocols, we successfully cryopreserved shoot apices from in-vitro plants of different Gentiana cultivars (lines). Although both protocols gave high survival percentages after storage in liquid nitrogen, the encapsulation-vitrification protocol had several distinct advantages over the vitrification protocol: (i) survival was higher under optimal conditions, (ii) the range of optimal exposure periods to the plant vitrification solution 2 (PVS2) was broader, and (iii) regrowth of cryopreserved shoot apices was apparently more vigorous and faster. Shoot apices from ten cultivars/lines of three Gentiana species (G. scabra, G. triflora, and G. pneumonanthe) were successfully cryopreserved using the two protocols with average survival of 49.0 percent and 73.7 percent for vitrification and encapsulation-vitrification, respectively. These results indicate that the two protocols optimized in the present study are promising for cryopreservation of a wide range of Gentiana genetic resources.