ABSTRACT
Vitrification and encapsulation-dehydration were tested for cryopreservation of Thymus moroderi Pau ex Martínez (Labiatae), an endemic plant from south-eastern Spain. For vitrification, shoot tips were loaded in a solution containing 0.4 M sucrose + 2 M glycerol for 20 min at room temperature, dehydrated in PVS2 solution for 0-105 min at 0 degree C, then immersed in liquid nitrogen (LN) for at least 1 day and rapidly rewarmed. The highest survival (71.4 percent) was obtained after 60 min PVS2 dehydration. Encapsulation-dehydration gave slightly lower results, with up to 50 percent explants survival. In the optimal protocol, donor plants were cold-hardened at 10 degree C for 5 weeks, excised shoot tips precultured for 48 h on MS medium with 0.08 M sucrose, encapsulated, pretreated in medium with 0.75 M sucrose for 19 h, desiccated to 22 percent moisture content (fresh weight basis), and immersed in LN. Vitrification thus appears more suitable than encapsulation-dehydration for cryopreservation of T. moroderi shoot tips.
Subject(s)
Cryopreservation/methods , Desiccation , Plant Shoots/growth & development , Thymus Plant/growth & development , Vitrification , Adaptation, Physiological , Cryoprotective Agents/pharmacology , Plant Shoots/physiology , Sucrose/pharmacology , Thymus Plant/physiologyABSTRACT
Thymus moroderi Pau ex Martinez (Labiatae) was successfully cryopreserved using the droplet vitrification method. After 20 min in loading solution at room temperature, shoot tips were dehydrated with PVS2 at 0 degree C for 30 min and immersed into LN. For thawing, shoot-tips were transferred into recovery solution for 15 min. A test of different recovery media revealed that the best results were obtained when the medium was supplement with 0.275 micromolar BA.
