Effect of heavy metals on physiological and biochemical features of Anabaena cylindrica

Some of the physiological and biochemical characters of Anabaena cylindrical grown in batch culture were studied in the presence of some heavy metals (Cd, Fe, Ni, Cu) and Al. The LC50 concentrations of the metals which inhibited the uptake of nitrate, ammonia, urea and phosphate at different levels. Cd and Cu caused the high st inhibition of the uptake of all nitrogen sources. Cu caused the greatest inhibition of the two enzyme activities; nitrate reductase and alkaline phosphatase, as well as inhibiting oxygen evolution and ATP content, followed by Al and Cd. The algal yield was reduced by more than 50% in the presence of the tested heavy metals. when nitrate was added, a similar yield reduction was found, whereas such reduction was less (33-47%) when ammonia or urea were added as the other nitrogen sources. (authors). 38 refs., 4 tab