Cryopreservation of calli by vitrification and plant regeneration of Rhodiola sachalinensis

A cryopreservation procedure was presented on the callus of Rhodiola sachalinensis by vitrification.Calli were precultured in 8% sugar solution in darkness for 5 days,followed by treatment with 60% PVS₂ at 25℃ for 20 min and with 100% PVS₂ in an alcohol bath at-20℃ for 2 hrs.The calli were then directly immersed into liquid nitrogen for 48 hrs.After rapid thawing in a water bath at 40℃,the calli were washed three times in MS liquid medium supplemented with 6-BA 2 mg/L,NAA 0.5 mg/L and 40% sugar solution,and then moved to MS solid medium containing 6-BA 2 mg/L and NAA 0.5 mg/L.The calli were cultured at 22℃ in darkness for two weeks,then under a light of 800 lx.Six weeks later,the calli of Rh.sachalinensis were fresh and green,showing vigorous growth and the survival rate reached 78.24%.The cryopreserved calli of Rh.sachalinensis could be induced to seedlings.