Biopolymers and cell. 1999; 15 (5): 343 - 359

Genome variability in plant somatic cells. 5. Growth and mitotic regime variations during adaptation to maintenance in vitro

A. Kunakh

Data on the dynamics of plant cell populations in the process of their adaptation to the growth conditions in vitro have been reviewed. In the course of the passaged culture obtaining a period of strain habituation being critical was discovered. Within this period (commonly the 2—8th passages) the intensive processes of cell population adaptation to autonomous growth outside an or¬ganism are evident. At this time there occur further rearrangement of physiological processes and cell population structure, even more essential versus the primary callus. The transition from the diurnal periodicity control mechanisms universal for an organism as a whole to the intracellular ones is observed. The homeostatic control mechanism specific for the population of cultured cells is estab¬lished. The positive selection of cells, adapted to the in vitro existence and elimination of unadopted ones are observed. These events are concurrent with the considerable changes in the growth rate and other morphological peculiarities of the cell strain, duration of the cell cycle and mitotic activity rhythm, the rise in poly¬morphism (heterogeneity) of the cell population in terms of many characters. Established, adapted cell strains tend to be characterized by the stability of traits originating in the period of strain habituation. The statement is that passaged cell culture presents the unique biological system — the clone population, in which the role of organisms' part is played by the cells originally programmed as a constituent of a mutticellular organism to accomplish the certain structural and functional tasks. Apart from being useful in the known fields of application can also serve as a model to study the details of variability and adaptation as well as the evolution of cell associations of different integrity level especially upon the transition from the higher level to the tower one i. e. under the conditions of so called «regressive evolutions.