1989 Volume 35 Pages 118-124
Culture conditions involved in the induction of cold hardiness by abscisic acid (ABA) and associated cellular changes were investigated using bromegrass cultured cells. The highest freezing tolerance (below -30℃) after 7 days of incubation was induced at the ABA concentrations between 75 and 500 μM and at temperatures between 25 and 30℃. This process was independent of the presence of light. Under these conditions, the growth was not depressed by ABA. High levels of cold hardiness were achieved at temperatures where growth was most remarkable. The decrease in the cellular water content was parallel to the level of cold hardiness induced. ABA induced several sets of cellular proteins and only two of them (25 and 200 kD) were also induced by the growth of cells at low temperature (3℃). As a method of preconditioning for cryopreservation, ABA treatment was more effective than cold or osmotic treatment in the case of bromegrass culture. Freezing of ABA-treated cells in 10% sucrose resulted in high rates of survival at -40℃. However, it is not always applicable to other cultured cells as it is affected by the genetic potential of cold hardiness of the plant and also some unknown factors like the origin of cultures or cell morphology.
