Callus induction, plant regeneration, and cryopreservation of Dendrobium findlayanum based on an encapsulation-dehydration technique

摘要

Dendrobium findlayanum, primarily distributed in Thailand and neighbouring countries like Myanmar and Laos, is at risk of extinction due to habitat decline and overexploitation. Cryopreservation has emerged as a promising method for orchid conservation. This study was carried out to optimize the conditions for callus induction, plant regeneration, and the cryopreservation of protocorms of D. findlayanum using an encapsulation-dehydration method. The orchid seeds successfully germinated on Vacin and Went medium. This medium, amended with 1 mg L16-benzylaminopurine (6-BA), was the most effective for callus induction, whereas a combination of 1 mg L 1 6-BA and 1 mg L1 naphthaleneacetic acid was sufficient for promoting plantlet regeneration. Protocormsof D. findlayanum were successfully cryopreserved using the following protocol: 24-h pretreatment of alginate-encapsulated protocorms with 0.5 M sucrose followed by 8 h dehydration. Random amplification of polymorphic DNA was carried out to detect the genetic stability of the cryopreserved protocorms and genetic differences were not detected between non-cryopreserved and cryopreserved protocorms.