CRYOSTORAGE OF EMBRYO AXES OF SEVERAL LARGE-SEEDED TEMPERATE TREE SPECIES

Embryo axes of 18 species in seven genera of temperate trees with large recalcitrant or suborthodox seeds were tested for their ability to survive desiccation and dry-freezing. Axes were dried under a stream of air overnight and frozen by immersion in liquid nitrogen. Thawed axes were rehydrated and grown in vitro on a medium containing 2 mg/liter each of benzylaminopurine and indoleacetylphenylalanine. Some survival of axis tissue occurred with each genus tested, but this included a variety of responses: germination or partial germination with callus in Juglans, most Carya, and Fagus; multiple bud production in Aesculus; mostly callus production in Corylus; and entirely callus in Castanea, Carya cordiformis, and Quercus. Survival rates of 100% were obtained in several species, but were lowest with species of Quercus, ranging from 0-40%. These results indicate that cryostorage should be possible for a number of difficult-to-store temperate tree seeds and could significantly reduce the amount of space needed for germplasm preservation in these species. © 1990.