Chromium toxicity on two linked trophic levels. II. Morphophysiological effects on Scenedesmus acutus.

The morphophysiological effects of Cr(VI) on Scenedesmus acutus were studied by light and fluorescence microscopy. Axenic cultures of S. acutus were grown in the presence of 1, 5, and 10 mg/liter of Cr(VI) supplied as K2Cr2O7. It was found that Cr(VI) inhibits cell proliferation and the formation of coenobia. It also induces alterations in cell morphology; depending on the dose, it induces the formation of multicellular plurinucleated aggregates or the appearance of large uninucleated cells. By using methylene blue staining, it was possible to identify the algal cells that had undergone irreversible damage.