RELATIONSHIP BETWEEN NITROGENASE SYNTHESIS AND THE C N RATIO IN THE NITROGEN-FIXING CYANOBACTERIUM ANABAENA-VARIABILIS/

The C/N ratio in the cells of nitrogen-fixing cultures of the cyanobac terium Anabaena variabilis is not a constant value under photoautotrop hic conditions but changes during the growth process. The nitrogenase activity increases with the C/N ratio, which results in an increased c ell nitrogen content. A decrease in C/N causes the nitrogenase activit y to decline.