[Kinetics of contact polarization of cells in induced tissues in amphibian embryos].

The curves of distribution of the cell polarization index (ratio of long and short cell axes) and diagrams of distribution of this index were plotted for the presumptive neuroectoderm explants and induced ventral ectoderm of the X. laevis gastrula. It was shown by three independent methods that the mean time of transition of a cell from the nonpolarized to the polarized state amounted to 5-6 min. The polarization was spreading as a continuous wave from one cell to another which is in contact with the former. The length of cell layer is reduced in the direction of the cell polarization wave at a rate of about 2-3 micron/min. Similar values are characteristic of the intact axial rudiments as well. The data obtained allow for the contact polarization of the cells to be considered as a spatially-continuous wave of the loss of stability of the initial non-polarized state.