EFFECT ON BIOCHEMICAL PARAMETERS OF CYANOBACTERIUM ANABAENA SP UNDER LEAD STRESS.

Effect of lead on Anabaena sp at five different concentrations (0.1, 0.5, 1, 1.5 and 2 ppm) were examined. Parameters such as growth response, pigment content, total protein content, and membrane damage, photosynthetic efficiency of PS II, SOD activity and heterocyst frequency were evaluated in laboratory conditions under control and treated conditions. Growth rate in all treated samples were much slower as compared to the control and the rate further decreased as the concentration of lead and days of incubation increased. The heavy metal toxicity is best observed by changes in growth of the algae. Protein content, photosynthetic pigment content (chl-a and car) and photosynthetic efficiency in terms of Fv/Fm of PSII. MDA accumulation in the alga in the treated sample is much higher as compared to control and the accumulation gradually increased as the day of exposure and concentration of heavy metal increased. SOD activity increased with increase in lead concentration and was observed maximum in 2 ppm as compared to control. Heterocyst frequency also decreased with increase in lead concentration and found to be minimum in treated sample.