Pregrowth-desiccation: a simple and efficient procedure for the cryopreservation of rice (Oryza sativa L.) embryogenic suspension cells.

Rice embryogenic suspension cells were successfully cryopreserved by a pregrowth-desiccation procedure. Cells were precultured in liquid AA medium containing 0.175 mol/L sucrose for 3 d and then in liquid AA medium containing 0.4 mol/L sorbitol for 1 d. After air-drying for about 20 h to a water content of 10%, the cells were placed into cryotubes and quenched into liquid nitrogen. Using this pregrowth-desiccation procedure, a survival rate of 96+/-6% (TTC reduction assay) or 100% (cell clump regrowth) was achieved. Cryostored cells revived very quickly during the recovery culture and they retained the ability to regenerate fertile plants. In conclusion, air-drying, a method usually employed in cryopreservation of seeds or shoot tips, can be used as a simple and efficient procedure for the cryopreservation of precultured rice suspension cells.