Effect of Different Concentration of Cadmium on Growth and Cellular Morphology of Green Algae Population of Scenedesmus quadricauda (Chlorophyceae)

The density¡ growth and cellular morphology in green algae Scenedesmus quadricauda (Chlorophyceae) population were investigated at different concentrations of 0¡ 5¡ 10¡ 50¡ 100¡ 200 and 500 mg/l of Cadmium in this study. The experimental conditions for culture of this species were included of culture medium of Bold Basal’s Medium¡ temperature of 25 ºC¡ light regime of 12 hours light: 12 hours dark¡ and light intensity of 60 µmol photons/m2/s. The experiment was carried out as completely randomized design for a 14-day period. Results showed that increment of population density of S. qaudricauda cultured with increase of concentration of Cd¡ significant decrease during experiment. The lowest cellular density (9.33 × 104 cell/mL)¡ minimum specific growth rate (0.009 /day) and maximum population doubling time (79.2 days) were obtained at 500 mg/l of Cd concentration. Cellular morphology (based on cells per colony) of S. qaudricauda population was considerably changed during experiment. The relative colony formation at lower of Cd concentrations dominated by only 1 cell/colony while the cell composition in the higher concentrations were tendency to more than 1 cell/colony. In overall¡ the response of S. qaudricauda to Cd concentrations increasing was to decrease in population.