EFFECT OF NUTRIENT SUPPLEMENT ON GROWTH AND NITROGENASE ACTIVITY OF SOME CYANOBACTERIAL STRAINS FROM SEMI–ARID SOILS

R. Nisha; A. Kaushik; C.P. Kaushik

Volume : IV, Issue : V, May - 2015

EFFECT OF NUTRIENT SUPPLEMENT ON GROWTH AND NITROGENASE ACTIVITY OF SOME CYANOBACTERIAL STRAINS FROM SEMI–ARID SOILS

R. Nisha, A. Kaushik, C. P. Kaushik

Abstract :

In the present investigation effect of various nutrient supplements iron, phosphate/potassium and exogenous nitrogen sources on growth and nitrogen fixing ability of cyanobacteria have been studied in terms of chlorophyll, carotenoid and nitrogenase activity. The response was found to be species specific to K+/PO43– and Fe3+ and nutrient saturation occurred at different concentration in term of photosynthetic pigment concentration. Amongst exogenous N–sources, nitrate alone had a stimulatory effect on chlorophyll of some strains while ammonium and amino acids tended to suppress the concentration of chlorophyll and other pigments. While exogenous nitrogen suppressed nitrogenase activity, the other nutrients significantly increased N2 fixing potential of the cyanobacteria