NITROGEN-FIXATION AND PIGMENT CONTENTS OF THE SYMBIONT ANABAENA-AZOLLAE FROM AZOLLA

Five cyanobacterial symbionts from Azolla filiculoides, two symbionts from Az. microphylla and two free-living cyanobacteria Nostoc muscorum and Anabaena variabilis were analyzed for chlorophyll (Chl) a, carote noids and phycobiliprotein contents, heterocyst frequency and nitrogen ase activity. The symbiont AS-S1 as well as the free-living N. muscoru m and An, variabilis contained highest amounts of Chl a and lowest amo unts of carotenoids. The C-phycocyanin content was always higher than that of allo-phycocyanin and C-phycoerythrin. Among the symbionts, AS- S1 contained the highest amount of C-phycocyanin and highest nitrogena se activity. Heterocysts were more abundant in An. azollae than in fre e-living cyanobacteria.