Pretreatment Strategies for the Cryopreservation of Plant Tissues

Preconditioning of plant material prior to cryopreservation is beneficial for increasing the survival of plant tissues. Pretreatment of plant cells and tissues can be divided into three categories. Cultural pretreatments may involve growth medium, cold acclimation or consideration of the plant part used. Chemical treatments may be osmotic or penetrating cryoprotectants. Desiccation treatments may involve air flow or desiccants. Pretreatments are crucial to the survival of plant tissues from cryopreservation. Since at present, cryoprotectants alone can not provide enough protection to untreated cells or tissues for high rates of survival. One or more of these pretreatment techniques is needed to condition the cells to withstand the stresses imposed by freezing in liquid nitrogen. This paper will review the pretreatments used in plant cryopreservation.