Cryopreservation of Doritaenopsis suspension culture by vitrification

Cells of a suspension culture of Doritaenopsis cv. New Toyohashi were placed in a mixture of 2 M glycerol and 0.4 M sucrose for 15 min at room temperature and then dehydrated with a vitrification solution (PVS2) for 1-3 h on ice and plunged into liquid nitrogen. The highest viability (64% by 2,3,5-triphenyltetrazolium chloride stainability) was obtained when the cells were precultured in liquid New Dogashima medium with 0.1 M sucrose and 1.0 mg/l abscisic acid for 1 week at 25  °C in the light. Dehydration by PVS2 was important for the cryopreservation of Doritaenopsis cells. Protocorm-like bodies were induced from cryopreserved cells without morphological variations.