[Dehydration in the cryopreservation of moist plant tissues and in seed maturation]

The possibility of long-term cryopreservation of plant objects depends on their water content. In orthodox seeds, it decreases at the late stage of maturation and is accompanied by the synthesis of protectors--sugars and proteins. These seeds easily withstand cryopreservation. Organs with a high water content, meristems, and recalcitrant seeds are dried in presence of sucrose before plunging in liquid nitrogen. In orthodox seeds, artificially dried moist seeds, and meristems, the cellular content forms glass structures that are estimated in frozen materials by differential scanning calorimetry and electron paramagnetic resonance methods. It is proposed that the glass cellular content is connected with the duration of cryopreservation. Methodical approaches to successive cryopreservation of moist plant tissues are described.