ИСТИНА

The main adaptation processes in populations of algae occur in the initial period of intoxication. So, after the triple intoxications of the culture S. quadricauda (0,1 → 0,1 → 0,1 mg/l of silver ion) and the subsequent transfer of the remaining cells (3-5% of living cells) in a clean medium without the toxicant, the structure of the restored population 30 day after matches that of the initial intoxication. Restoration of the number of cells in culture S. quadricauda after the triple intoxications of potassium dichromate (10 → 10 → 10 mg/L) occurred due to a small number of living cells (3-5%). During the 90 days of intoxication, there is at least 30 generations of cells. The results make it possible to consider the remaining 3-5% of living cells S. quadricauda as a resistant cells to toxicants for a long experiment ie there is a genotypic adaptation. Formation of genotypic adaptation can be explained by the presence of the original pool of resistant cells in a heterogeneous population. Resistant cells in the population occur randomly by rare spontaneous mutations that occur during replication, prior to contact with the contaminant (pre-selective mutations), which gives the possibility of microalgae to survive in contaminated environments.