ABSTRACT
Cryopreservation is the preservation of viable cells, tissues and organs in liquid nitrogen, at -196°C. This storage procedure can be successfully applied to a wide range of organisms and biological tissues (Benson and Lynch, 1998; Benson et al., 1998; Harding et al., 1997) and it is being increasingly used to conserve crop plant germplasm (Ashmore, 1997). Thus, Cryopreservation provides a long-term storage method for the conservation of plant genetic resources which cannot be maintained using conventional preservation methods, such as by seed banking. The application of Cryopreservation must be considered in the context of other conservation options; it is best used as a complementary method, for example, when other storage protocols are not appropriate. Many examples of the appropriate application of plant Cryopreservation are presented by the authors of chapters in this volume. Thus, although initial progress in plant Cryopreservation was made using arable crop plant germplasm, more recently, it is being increasingly used to conserve endangered species (see Pence, Chapter 15 and GonzálezBenito et al., Chapter 16, this volume) and tropical rain forest trees (see Marzalina and Krishnapillay, Chapter 17, this volume). This increase in applications is largely due to the development of improved cryoprotection strategies which have made the technique more accessible to end users.
