CRYOPRESERVATION OF NARCISSUS L. 'CARLTON' SOMATIC EMBRYOS BY DROPLET VITRIFICATION

摘要

The aim of this study was to develop an efficient cryopreservation protocol for the geophyte giant narcissus that guarantees a high rate plant regeneration. Globular somatic embryos (1, 2, and 3 mm diameter) were picked up from the embryogenic callus. The embryos were treated with plant vitrification solution (PVS2) for 10, 20, 30, 45, and 60 min. For 1 mm embryos the survival rate does not exceeding 76.7%, irrespective of PVS2 exposure duration. In case of 2 mm and 3 mm embryos, low survival (73.3-86.7%) was observed only after 10 and 20 min of PVS2 exposure. In other cases, the survival rate ranged between 93.3 and 100%. During post-rewarm regeneration, the highest growth rate amounting to 26.7% was achieved after 45 min treatment of PVS2, in case of the 2 mm embryos. The best regrowth among 1 mm embryos, at level 20%, was achieved after 60 min treatment of PVS2. Large sized embryos did no regenerate at all. The regenerated globular embryo formed a few secondary embryos. All the secondary embryos formed bulblets, which exhibited the same morphology as that of non-cryopreserved, control bulblets.