CRYOCONSERVATION OF EMBRYOGENIC CALLUS OF NORWAY SPRUCE [PICEA-ABIES (L) KARST] - INFLUENCE OF DIFFERENT FACTORS ON CALLUS RECOVERY AND ON EMBRYO AND PLANTLET PRODUCTION

A new process for the cryoconservation of Picea abies embryogenic calli has been established which allowed regrowth after lag phase duration lower than 3 days. Regrowth after freezing in liquid nitrogen depends on several parameters : nature and concentration of cryoprotectants (sucrose, dimethylsulfoxide, propanediol), prefreezing temperature and thawing rate. Regrowth occurred directly by proliferation of proembryos. Selection of meristematic cells induced by cryopreservation allowed rejuvenation of senescent cultures. Cryopreserved calli displayed more rapid development of embryos than control. Embryos obtained from frozen calli differenciated in normal plantlets.