CRYOPRESERVATION OF FRASER PHOTINIA (Photinia x fraseri Dress.) VIA VITRIFICATION-BASED ONE-STEP FREEZING TECHNIQUES

Abstract

An efficient vitrification-based cryopreservation procedure was developed for Fraser photinia shoot apices by assessing the influences of various vitrification solutions (PVS1, PVS2, PVS3 and VSL) and different vitrification methods (cryovial vitrification, droplet vitrification and droplet freezing) on shoot regrowth. Moreover, influences of cold-hardening period (0 to 8 weeks), preculture medium (with sucrose and proline) and regrowth medium (QL plus 4.4, 8.8 and 17.6 mu M BA) were also evaluated. Among the different procedures tested, best shoot regrowth (40.3%) was achieved by using a droplet vitrification technique in which cold-hardened and precultured shoot apices were vitrified for 120 min at 0 degrees C in droplets, rapidly cooled, thawed and then cultured on 17.6 mu M BA-containing QL medium. Overall results indicated the importance of not only the composition of vitrification solution, and preculture and regrowth media, but also the application of an appropriate vitrification technique to achieve optimum recovery post-cryopreservation.