Cryopreservation of In Vitro. Grown Apical Shoot Tips of Strawberry by Vitrification.

Abstract

After the strawberry shoots on culture medium were cold-hardened at 5°C for 20-30 days, shoot tips were dissected and precultured at 5°C for 1 day on MS medium containing 2 M glycerol and 0.3M sucrose. Precultured 10 shoot tips were placed in 2.0ml cryotubes each, and treated with a mixture of 2M glycerol and 0.3M sucrose for 20min at 25°C. They were then treated with PVS2 solution for 50min at 25°C, and immersed into LN. After rapid rewarming in water at 35°C, they were transferred onto the MS medium containing 1gl-1 PVP and 0.2mgl-1 BA and grown under standard conditions. By this protocol, survival rate of cryopreserved “Donner” shoot tips reached 93%. This protocol was successfully applied to 7 other races or lines of strawberry with high survival rates. These results prompt us to setting up large-scale strawberry LN storage system.