ABSTRACT
Many of the plant materials stored by cryopreservation come from tissue culture systems. It is vitally important that the culture system produce healthy plants for the process. Cultures in less than optimum condition have lower regrowth than those in good condition. Small plant cells with few vacuoles are the easiest to cryopreserve. Most cryopreservation protocols involve preconditioning stages in culture. These may include growth on highly osmotic media, cold acclimation, or extended culture without transfer. Sequential transfer to medium with increasing sucrose concentrations, cold
acclimation, growth on abscisic acid, or glycerol are used to increase osmotic tolerance when plants are desiccation sensitive. Most of these techniques improve cryopreservation tolerance by adding solutes to the cytosol or developing desiccation tolerance in the cells. Recovery following cryopreservation is also dependent on in vitro culture systems in most cases. The optimal growth room temperature and lighting as well as the proper recovery medium can greatly affect regrowth.
