PRELIMINARY-STUDY ON CRYOPRESERVATION OF THE CONCHOCELIS OF PORPHYRA-YEZOENSIS

Cryopreservation of the conchocelis of Porphyra yezoensis was attempted. Conchocelis cells were frozen at -30 or -80-degrees-C in various concentrations of seawater containing several cryoprotectants. The viability of conchocelis cells was evaluated by staining them with neutral red. DMSO was the best cryoprotectant among the compounds tested. The cryoprotective effect of DMSO varied with the concentration of seawater, and was maximal at a seawater concentration of 50 %. The combination of DMSO and sorbitol was more effective for the long survival of conchocelis than DMSO alone. The survival rate of conchocelis frozen at - 80-degrees-C in 50 % seawater with 5 % DMSO and 0.5 M sorbitol fell below 1 % in three days. However, when frozen at -30-degrees-C, 55 % of the conchocelis cells survived for one day and 16 % survived for a week.