EFFECT OF DIFFERENT FORMS OF NITROGEN ON GROWTH, NITROGEN FIXATION AND PIGMENT CONTENTS OF CYANOBACTERIA

Document Type : Original Article

Author

Agricultural Microbiology Department, Soils. Water Res. and Environ. Institute. Agric., Res. Center (ARC), Giza, Egypt

Abstract

Growth, nitrogen fixation and pigment contents were followed in four batch cultures of local cyanobacteria strains, namely Anabaena so. Nosloc muscorum, Tolypolhrfx tenufs and Calofhrfx brevissima supplemented with range of Nitrate-N. urea-N and Ammonium-N. All the nitrogen sources decreased significantly the growth of the tested cyanobacteria strains in the term of dry weight criteria. Cyanobacteria strains exhibited variable nitrogen fixed amounts, chlorophyll a and C— phycocyanin amounts due to the exposure any of Nitrate—N, urea-N and Ammonium~ N However, the ability of these cyanobacteria strains to assimilate the nitrogen source differs from each other. This could be explained by giving the assimilation order of the tested nitrogen sources as NO;.N :- urea-N > ammonium-N for all cyanobacteria strains.