Cryopreservation of non-precultured protocorms of Acampe rigida (Buch.-Ham. ex Sm.) P.F. Hunt using V cryo-plate and D cryo-plate methods

Non-precultured protocorms of Acampe rigida (Buch.-Ham. ex Sm.) P.F. Hunt were used to find the suitable duration time for dehydration on V cryo-plate and D cryo-plate methods. For V cryo-plate method, non-precultured protocorms were dehydrated with PVS2 solution for 0, 20, 40, 60 and 120 min. The results showed that protocorms dehydrated with PVS2 solution for 40 min gave the highest survival score at 0.08 and gave the highest percentage of survival at 16.67% which was higher than the control (+LN; 0 min), but most protocorms showed dark green color and developed slower than the control (-LN; 0 min). The suitable treatment for V cryo-plate in this study is exposing to PVS2 solution for 40 min. For D cryo-plate method, non-precultured protocorms were dehydrated with silica gel for 0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 h. The results showed that protocorms dehydrated with silica gel for 1.0 h gave the highest survival score at 0.56 and gave the highest percentage of survival up to 74.19%. Most protocorms with dark green developed slower than control (-LN; 0 min). The suitable treatment for D cryo-plate method in this study is dehydrating with silica gel for 1.0 h. An unpaired t-test was used to compare the data of survival score between suitable treatments from V cryo-plate and D cryo-plate methods. The suitable treatment for cryopreservation of protocorms of A. rigida is cryopreserving with D cryo-plate method dehydrated with silica gel for 1.0 h.