As. Popov et La. Volkova, CRYOPRESERVATION AND SOME CHARACTERISTICS OF DIOSCOREA-DELTOIDEA CELL-CULTURES IN THE VITAMIN-FREE MEDIUM, Russian journal of plant physiology, 41(6), 1994, pp. 815-820
The extermal cryopreservation procedure for Dioscorea deltoidea Wall.
suspension cell cultures is briefly described, and the main causes of
cell injury are discussed. The effect of long-term culturing in the vi
tamin-free medium on cell freezing tolerance, ploidy, aggregation leve
l, and growth rate were studied in two D. deltoidea strains: DM-0.5 an
d DM-8. The ploidy distributions within the cell populations were affe
cted by vitamin deficiency. As a result, the high-ploidy cells prevail
ed in the DM-0.5 strain and haploid cells were predominant in the DM-8
strain. The level of cell aggregation declined in the DM-8 strain. Th
e cultures retained both high viability and the capacity to actively g
row. However, after programmed freeze-thaw cycles, the survival rates
of both strain cells dropped two- to threefold. After returning to a v
itamin-containing medium, the initial ploidy distribution and cell cry
otolerance were restored High-ploidy and haploid D. deltoidea cells tu
rned out to be poorly resistant to cryodamage, whereas di- and triploi
d cells were the most resistant. Gene dosage and balance presumably pr
ovide for the cell metabolism to alleviate the cryoinjury and for the
optimum composition of the plasmalemma, a primary target for cryoinjur
y.