Cryopreservation of Dendrobium cruentum Rchb. f. seeds by D cryo-plate and V cryo-plate techniques

Cryopreservation is an important tool for long-term storage of plant species. In the present study, the successful protocol for Dendrobium cruentum Rchb. f. seed cryopreservation based on cryo-plate technique was observed by D cryo-plate and V cryo-plate techniques. D cryo-plate used sterile laminar air-flow and V cryo-plate used cryoprotectant solution (PVS2) for dehydration process. From seed viability test, 93.8% were viable. Optimizing dehydration time leaded to successful cryopreservation. The same interval times of dehydration for both techniques were observed by using 0, 30, 60, 90 and 120 min. After cryopreservation, seeds were cultured on modified VW agar medium for germination and regrowth. The results indicated that D cryo-plate technique with 60 min of dehydration resulted in higher germination percentage (68.9%) and recovery (57.8%) than V cryo-plate technique exposed to PVS2 solution for 30 min (64.7% germination and 46.1% recovery). Thus, the excessive of dehydration may cause the reduction of germination and plant regeneration. However, D cryo-plate technique proved to be more appropriate to cryopreserve D. cruentum Rchb. f. seeds.