RICE CELL CRYOPRESERVATION - THE INFLUENCE OF CULTURE METHODS AND THEEMBRYOGENIC POTENTIAL OF CELL-SUSPENSIONS ON POSTTHAW RECOVERY

Protoplast-derived plants were regenerated from cryopreserved embryoge nic suspension cultures of the Japonica rice cultivar Taipei 309 at fr equencies comparable to those of the original non-frozen cultures. The duration of cryogenic storage did not affect the embryogenic potentia l of suspension cultures re-established from thawed material. Cells fr om embryogenic cultures regrew after thawing significantly faster than those from non-embryogenic cultures. The method and frequency of subc ulture of cells after thawing and the nitrogen status of the recovery medium significantly influenced the rate of cell regrowth. The most ra pid post-thaw cell regrowth occurred in cell samples maintained on fil ter paper overlying semi-solid medium lacking inorganic nitrogen and s ubcultured 3 days after thawing.