Abstract
Complete vitrification can avoid the potentially damaging effects of both extracellular and intracellular crystallization. This method is very useful for long-term storage of germplasm due to minimum space and maintenance requirement. Three cryogenic procedures; vitrification, encapsulation-dehydration and encapsulation-vitrification, are suitable for cryopreservation of meristerms or somatic embryos. In this paper, the advantageous and disadvantageous between these procedures were evaluated and discussed. The vitrification method produces a high rate of shoot formation after cryopreservation, requires a minimal time for dehydration, yet poses difficult when handling a large number of meristems during the treatment phase. The encapsulation-dehydration method is easy to handle and alleviates dehydration process, however, introduces a low survival rate. It also produces a longer lag time for growth recovery and requires considerable time for dehydration. Contrarily, the encapsulation-vitrification method provides a high degree of survival, greatly shortens the dehydration time, and provides easy handling of even cells or small explants such as hairy roots.
