Effect of pH on aluminum uptake and differential aluminum tolerance in cyanobacterial strains: A bioresource for agricultural and environmental sustainability

The nitrogen-fixing cyanobacterial strains Scytonema sp., Nostoc muscorum, Cylindrospermum sp., and Anabaena sp., were subjected to different concentrations of aluminum at different pH 4.0, 6.0, and 7.0 along with control. Al metal uptake was highest at pH 4. Enhanced peroxidase, superoxide dismutase activity and the accelerated lipid peroxidation depicted a significant accumulation of superoxide and peroxide radicals in Nostoc muscorum exposed to higher concentrations of Al (8 and 16 mu M). The non-enzymatic antioxidants, proline and total phenols also increased in a dose-dependent manner Overall, acid Al stress led to differential tolerance and bioavailability of Al metal in various cyanobacterial strains. Among all the strains, Nostoc muscorum tolerated acid/Al stress exceedingly well. The results of the present study suggest plausible implication of Al tolerant cyanobacterial strain as bio-fertilizers in acidic soils. The intrinsic abilities of cyanobacterial strain to adsorb Al from soil may reduce its bioavailability there by increasing crop productivity.