Cryopreservation of protocorm-like bodies of Vanda lilacina Teijsm. & Binn., a Thai orchid species, by V-cryo-plate and D-cryo-plate methods

Protocorm-like bodies (PLBs) of Vanda lilacina Teijsm. & Binn. were used to study for new cryopreservation techniques, V-cryo-plate and D-cryo-plate methods, on survival score and percentage of survival. For V-cryo-plate and D-cryo-plate methods, PLBs were dehydrated with PVS2 solution for 0, 20, 40, 60 and 120 min and silica gel for 0, 0.5, 1, 1.5, 2, 2.5 and 3 h, respectively. The results showed that for V-cryo-plate method, the suitable treatment for cryopreserved PLBs of V. lilacina was dehydrated with PVS2 solution for 20 min. It gave survival score at 0.31, higher than control (+LN; 0 min), and gave percentage of survival at 33.33%. Moreover, PLBs showed survival as active green PLBs, but grew and developed slower than control (-LN; 0 min). For D-cryo-plate method, the results showed that the suitable treatment for cryopreserved PLBs of V. lilacina was dehydrated with silica gel for 1 h. It gave the highest survival score at 0.78 and percentage of survival was up to 83.78%. Moreover, PLBs showed the same growth and development as control (-LN; 0 min). The suitable cryopreservation method of V. lilacina PLBs is D-cryo-plate method using silica gel for 1 h in dehydration step.