INTRACELLULAR PROLINE ACCUMULATION IN SOME ALGAE EXPOSED TO COPPER AND CADMIUM

The intracellular proline level in four species of algae: Anacystis ni dulans, Chlorella sp., Pediastrum duplex, and Nitzschia palea, was enh anced when they were treated with deleterious concentrations of Cu2+ O r Cd2+. The maximum enhancement of proline level followed the order: C hlorella>Pediastrum>Anacystis>Nitzschia for either metal ion, but copp er caused a greater accumulation of proline than did cadmium. Proline accumulation appears to be a general response of algal cells to copper and cadmium. The present study characterizes the time course of proli ne accumulation. In addition, experiments conducted with Chlorella sp. and A. nidulans showed that when incubated under illumination, metal- treated cells accumulated more proline than they did in the dark. The possible role of proline accumulation is discussed.