Cryopreservation and the Retention of Biosynthetic Potential in Cell Cultures of Medicinal and Alkaloid-Producing Plants

Abstract

The storage of plant cell cultures is of immense importance not only for the conservation of germplasm, but for its use in large quantities for the production of medicinal compounds and other important pharmaceutical products. Although various in vitro methods that reduce the rate of growth have been employed (see Bajaj 1986a), they do not offer long-term conservation. Cryopreservation has the advantage of overcoming this problem. During the last decade tremendous progress has been made and literature accumulated on the freeze preservation of plant cell, tissue, and organ cultures, and entire plants have been regenerated from cultures cryostored in liquid nitrogen (−196°C) for various lengths of time. The technological refinements permit almost 100% survival of retrieved cultures in some plant species. Although basic work needs to be carried out to study the effect of freezing on long-term storage, with particular reference to genetic stability, it has been established beyond doubt that cryopreservation will increasingly be employed for conservation of germplasm and storage of cell cultures. In this chapter, work on freeze preservation of in vitro cultures of medicinal and alkaloid-producing plants is reviewed, and its potentials for the retention of the biosynthetic capacity of cell cultures and their use in pharmacy is pointed out. For review of the subject on other plants, detailed technology, factors affecting cryoability, basic and fundamental aspects of cryopreservation, problems involved and the literature, especially on agricultural crops, refer to the author’s earlier publications and lectures delivered at various international symposia (Bajaj and Reinert 1977; Bajaj 1979a, b, 1983a, b, 1984a, b, 1985a, b, 1986a-d, 1987).