| Research Abstract |
A cryopreservation technique of genetic resources of horticultural crops consists of a combination of the tissue culture-derived plant regeneration technique and the various technique which enables survival of the frozen-thawed tissues. This study examined fundamental phenomena relating to the techniques.
1.Establishment of plant regeneration systems through tissue culure. (1), In Actinidia arguta, micropropagation in a short period could be realized through etiolation culture in which nodal segments excised from the cultures, which were derived from in vitro culture of nodal segments of current shoots, were cultured in the dark. (2), All shoots obtained in Actinidia polygama petiole culture formed roots and developed into plantlets. (3), Actinidia kolomikta showed the same system as in Actinidia polygama..
2.Changes in freezing tolerance of tissues. (1), In cold acclimation period through autumn and winter, shoot tips of Lonicera caerulea var. emphyllocalyx growing in field rose its freezing tolerance, lowered water content, and increase tri saccharides. Cold acclimation of cultures increased freezing tolerance of its nodal segments. (2), In shoot tips of Asparagus officinalis growinng in the field, preculture enhanced sugar uptake, dehydration and freezing tolerance rise.
3.Survival of tissues frozen and thawed. (1), Lateral buds of Actinidia arguta grown in field showed 50% survival after the freezing solution-immersion, slow cooling-dehydration, and liquid nitrogen-immersion cryopreservation. (2), Inlateral buds excised from shoots of Actinidia arguta cultures, cold acclimation (5ﾟC,4weeks+0ﾟC,2 weeks) or preculture (a high sugar concentration-medium 2 days) promoted survival.
The results obtained in this study are considered to contribute to the plant genetic resources cryopreservation in future.
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