ISHS Acta Horticulturae 560: IV International Symposium on In Vitro Culture and Horticultural Breeding
CRYOPRESERVATION OF PLANT GERMPLASM |
| Authors: | B. Panis, R. Swennen, F. Engelmann |
| Keywords: | germplasm collection, hardening, cryoprotection, vitrification, in vitro culture, freezing, sugar, dimethyl sulphoxide |
| Abstract:
Plant germplasm stored in liquid nitrogen (-196°C) does not undergo cellular divisions. In addition, metabolic and most physical processes are stopped at this temperature. As such, plants can be stored for very long time periods and both the problem of genetic instability and the risk of loosing accessions due to contamination or human error during subculturing are overcome. Most cryopreservation endeavours deal with recalcitrant seeds, in vitro tissues from vegetatively propagated crops, species with a particular gene combination (elite genotypes) and dedifferentiated plant cell cultures. Sofar, cryopreservation procedures are developed for in vitro tissues and recalcitrant seeds of about 100 and 40 species, respectively. There is still a limited number of cases where cryopreservation is used routinely for plant germplasm conservation, mainly because the techniques need to be adapted for each species in function of its natural freezing resistance, explant size and type, and its water content. Care must be taken to avoid ice crystallisation during the freezing process, which otherwise would cause physical damage to the tissues. The existing cryogenic strategies rely on air-drying, freeze dehydration, osmotic dehydration, addition of penetrating cryoprotective substances and adaptive metabolism (hardening) or combinations of these processes. | |
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