Auswirkungen von Cu,Cd und Atrazin auf den Stoffwechsel der einzelligen Grünalge Scenedesmus subspicatus

Influence of Cu, Cd and atrazine on the metabolism of the unicellular green alga Scenedesmus subspicatus The effect of Cu, Cd and atrazine on biomass and cell number was studied in 24h old cell cultures of untreated Scenedesmus subspicatus. Furthermore, the effect of some enzymes of the N-metabolism, on peroxidase and protein content was investigated in long term experiments in which the Scenedesmus strains were adapted to high concentrations of Cu, Cd and atrazine.

• In the 24h experiments, atrazine was more toxic than copper according to biomass production and cell number.
• The determination of the enzyme activities from the adapted strains showed positive and negative effects on enzymes of the N-metabolism. Under high copper concentrations, nitrate reductase activity in the copper strain was reduced and nitrite reductase significantly increased. The effects on the activity of the other enzymes of the copper strain were not significant. The protein content, however, was significantly decreased. Cd and atrazine had no significant effects on the activities of nitrate and nitrite reductase and glutamine synthetase or on protein content. Only the glutamate dehydrogenase showed a significant increase in activity under high concentrations of atrazine.
• All substances tested increased the activity of peroxidase, but only the effect of Cd was significant.
• All adapted strains secreted nitrite into the culture medium. The secretion was significantly increased under the influence of copper.