[Number of whorls and umbel rays in Acetabularia].

It was found in the proposed model of morphogenesis of Acetabularia that the number of whorls N (as well as the number of umbel rays) depends on the degree of mechanical instability of the deforming cell wall (the greater is instability, the higher is the value N). The genetic control of final morphogenetic processes can be realized by setting definite physical conditions and properties. The theoretical estimates of N carried out for different cases agree fairly well with the experimental data obtained.