Development of a Cryopreservation Protocol for Vanilla Siamensis: An Endangered Orchid Species in Thailand.

BACKGROUND

Vanilla siamensis is listed in Appendix-II of Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) as an endangered species in Thailand.

OBJECTIVE

To develop an optimum cryopreservation protocol for V. siamensis.

MATERIALS AND

METHODS

Protocorms were precultured on solid ½ MS medium with 0.5 M sucrose for 0-7 d. For encapsulation-dehydration, encapsulated protocorms (beads) were dehydrated for 0-6 h. In the case of encapsulation-vitrification, the beads were loaded with a plant vitrification solution 2 (PVS2) at 0 ˚C for 0-90 min.

RESULTS

Protocorms precultured for 3 d gave the highest post-cryopreservation survival of 17%. Dehydration of the encapsulated protocorm beads for 4 h gave the highest survival of 33% and a regrowth of 25%. Protocorms subjected to the encapsulation-vitrification method did not survive at all.

CONCLUSION

Protocorms precultured with 0.5 M sucrose for 3 d, encapsulated with 3% sodium alginate and dehydrated to a moisture content c. 14% before plunging into LN was a suitable method for the successful cryopreservation of V. siamensis protocorms.