Cryopreservation of Schisandra chinensis (Turcz.) Baill callus and subsequent plant regeneration.

Cryopreservation has been proven significance as a technique for promising the long-term conservation of plant germplasms. This study aimed to establish a cryopreservation protocol for calli of Schisandra chinensis (Turcz.) Baill, and to explore the effects of different process parameters on callus viability. Effects of desiccation duration, cryoprotectants and cryopreservation methods, thawing temperature, and post-culture conditions on the viability of cryopreserved calli were assessed. Among different cryoprotectants and freezing procedures, the highest survival was recorded when the water content of callus after 30 min desiccation was 57.3%, were loaded into a cryoprotectant containing 10% ethylene glycol, 8% glucose, and 10% DMSO, and frozen slowly (-1°C/min). Rapid thawing at 40°C for 2 min demonstrated the best recovery of cryopreserved S. chinensis calli. Post-culturing in darkness for one week before transfer to light conditions (under 16 h photoperiod at 36 µmol·m-2·s-1) was beneficial to callus regeneration. Plants regenerated through somatic embryogenesis from cryopreserved calli remained ploidy stable after cryopreservation. The callus cryopreservation procedure established in this study is a promising tool for the conservation of S. chinensis resources.