%0 Journal Article
%T Influence of osmotic and metal stresses on nitrogenase activity of cyanobacteria ysolated from paddy fields
%A G Okmen
%A G Donmez
%A S Donmez
%J African Journal of Biotechnology
%D 2007
%I Academic Journals
%X Samples were collected from paddy fields in Corum-Turk.ye. Nitrogen-free BG-11 medium was used for isolation of nitrogen fixing cyanobacteria. Acetylene reduction technique was used to determine the effects of different chemical agents on the nitrogenase activities of the cyanobacteria, which were identified at the genus level. Nostoc showed the highest nitrogenase activity (0.09 ethylene  那l/mg.h) at 50 mM salt concentration. At 60 mM sucrose concentration, Nostoc showed the highest nitrogenase activity (0.08 ethylene  那l/mg.h). The highest tolerances for the metals were present in Anabaena (0.006 ethylene  那l/mg.h) for iron (20 ppm), Nodularia 0.1 ethylene  那l/mg.h (for manganese 20 ppm) and Nostoc 0.96 ethylene  那l/mg.h (for zinc 5 ppm) .
%U http://www.ajol.info/index.php/ajb/article/view/57802