CHANGES IN CULTURE-GROWTH DYNAMICS AND CE LL-SIZE IN A SCENEDESMUS-QUADRICAUDA UPON ACTION OF POTASSIUM DICHROMATE

The effect of potassium dichromate in concentrations of 0.5 to 10 mg/l on a laboratory culture of Sc. quadricauda algae was studied in stand ard conditions. The total cell numbers decreased at potassium dichroma te concentrations over 1 mg/l, and the proportion of living cells decr eased at all studied concentrations. A positive correlation was found between changes in cell size and their numbers at toxin concentrations of 1 and 3 mg/l, and a negative correlation was found between the rel ative size and the cell numbers at 3 and 10 mg/l. This may be due to d ifferent intensity of growth inhibition and cell division under the in fluence of the toxin. The culture sensitivity to the toxin increased i n autumn and decreased in the spring.