Freeze-Preservation of Cultured Flax Cells Utilizing Dimethyl Sulfoxide

Abstract

Since the first use of glycerol (14) and dimethyl sulfoxide (DMSO) (8) as protective agents during freeze-preservation of cells, numerous types of tissue from many different organisms have been successfully preserved for long periods of time (11). Cultured mammalian cell lines have been preserved in a defined medium in the presence of glycerol (5) or DMSO (2) and a culture bank of certified animal cell lines has been established. Similar techniques have not been described for the successful low temperature storage of cultured cells of higher plants. Although Caplin (3) has reported that reduced growth of plant tissue cultures under mineral oil can increase the subculture period from weeks to months. such tissue is still growing and capable of variations in differentiative ability. Well-documented studies have concluded that long-term subculturing of plant cells may lead to increased chromosome abnormalities which appear in some instances to be correlated with loss of differentiative capacities of the culture (12, 20). Attempts to preserve plant tissue cultures should, therefore, aim at a total arrest of growth Cells of overwintering plants can naturally withstand low temperatures for several months. and the nature of survival properties possessed by cold hardy cells has recently been reviewed (7). However. relatively few studies have been concerned with the protective effects of various agents. Recently, ethylene glycol and DMSO were found to protect tissue sections of mulberry twigs from damage due to cooling in liquified nitrogen and subsequent warming (16,17). These reports prompted me to examine several methods which combined chemical treatment and low temperature for the preservation of plant tissue cultures. This communication describes a freeze-thaw method using DMSO for low temperature storage of flax cell cultures for short periods of