Cryopreservation of Callerya speciosa (Champ.) Schot through droplet-vitrification

Cryopreservation is a practical method for the safe preservation of plant genetic resources. Impregnation with cryoprotective agents and the use of suitable explants are key factors for a successful procedure. It is, however, often difficult to work with "hairy" explants because of their high surface tension preventing an efficient treatment with cryoprotectant. Axillary shoot segments with one bud of Callerya speciosa were successfully cryopreserved by droplet-vitrification. The results showed that 1 mm shoot segments with one axillary bud excised from in vitro shoots could be used as explants for cryopreservation. The best pretreatment was performed with loading solution (LS), applied for 240 min at 25oC on a shaker at 150 rpm. This was followed by a plant vitrification solution (PVS2) treatment at 0oC for 60 min and rapid freezing in liquid nitrogen. Especially, rotation at 150 rpm proved to be essential to obtain high regrowth rates up to 60%.status: publishe