Nowadays cryopreservation is considered to be the most efficient method for the protection of plant genetic resources. The technology is attracting more and more attention among both research and commercial laboratories worldwide. However, it is a relatively new technique, which still requires a lot of exploration. The influence of cryopreservation on the plant material genetic stability is one of the most interesting aspects. Due to the high costs and complexity of specimens preparation, the histological and ultrastructural observations are performed infrequently. The contemporary research suggest, that meristematic cells with dense cytoplasm and low level of hydration are the most suitable for cryopreservation. More differentiated cells with larger vacuoles do not survive the storage in liquid nitrogen, although sometimes it is possible for the young parts of leaf primordia. Usually cryopreservation does not alter the cell structure. It is observed occasionally, however, that the pretreatment and dehydration steps may cause some more or less reversible changes (e.g. starch accumulation), which can affect the explant morphogenetic response/potential.

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