Effects of copper on Enteromorpha flexuosa (Chlorophyta) in vitro

摘要: Enteromorpha species are widely used as biomonitors of copper (Cu) contamination in coastal waters, but the effects Cu at subcellular level and possible mechanisms metal resistance scarcely known. To contribute to understanding accumulation process macroalgae species, we exposed adult individuals flexuosa 50, 250, 500 microg Cu/L seawater for 5 days under controlled conditions. Thereafter, gross photosynthesis rate (GPR) were measured. Conventional transmission electron microscopy (CTEM) energy-dispersive X-ray analysis (EDXA) study cellular level. Treatments with 250 observed cause an inhibition GPR algae. samples microgCu/L was 5284+/-561 Cu/g (dry wt), whereas control (no addition), 9+/-1 microg/g. In cells plants undergoing 50 treatment, cytoplasm clearly vacuolated. Thickening cell walls increase relative number starch granules lipid bodies main changes Cu/L. EDXA algae after exposure detected mainly vacuole precipitates. also chloroplasts some epiphytic bacteria. It concluded that E. did not avoid penetration into consequently its toxic concentrations Precipitates containing vacuoles should be related a immobilization mechanism, minimizing toxicity cells. The bacteria can act biofilter diminishing availability free Cu(+2) accumulation.