Chrysanthemum low-temperature storage and cryopreservation: a review

Chrysanthemum (Dendranthema x grandiflora (Ramat.) Kitamura) is an ornamental plant that responds well to in vitro growth conditions. This receptivity makes it a particularly attractive target for low-temperature storage and cryopreservation studies. This review examines in detail the protocols thus far used to achieve the short- to long-term low-temperature and cryostorage of important chrysanthemum germplasm. Occasionally, medicinal chrysanthemum species have also been cryostored, and these studies are also examined in detail. Since chrysanthemum is sensitive to both osmotic stress and chemical toxicity of vitrification solutions, a generalized protocol for the cryopreservation of chrysanthemum apical or axillary shoot tips is proposed: excision of apical or axillary shoot tips after 4 or 7 weeks, respectively, from final subculture; progressive preculture with 10 % sucrose for 31 h, 17.5 % sucrose for 17 h, then 25 % sucrose for 7 h; osmoprotection with 17.5 % glycerol + 17.5 % sucrose for 40 min; cryoprotection with PVS3 (50 % glycerol + 50 % sucrose) vitrification solution for 60 min (axillary) or 90 min (apical); cooling and warming using aluminium foil strips; unloading with 30 % sucrose for 40 min. When smaller axillary shoot tips are used, cryoprotection of samples with 37.5 % glycerol + 15 % DMSO + 15 % ethylene glycol + 22.5 % sucrose at 0 A degrees C for about 60 min can be applied.