Impact of Salinity and pH on Several Species of Anabaena (Nostocaceae, Nostocales) Isolated from Rice Fields in Iran

The purpose of this study is to develop a biofertilizer based on filamentous nitrogen-fixing cyanobacteria selected from rice fields and to generate a technological package compatible with its use for the rice crop in Iran. Cyanobacteria was isolated and purified from rice fields in Kalate Naderi. Inthis research we studied the effect of salinity(NaCl, 0, 1, 2 and 4%) and pH (5, 7, 9 and11) on growth and chlorophylla contents in six species of Anabaena. Results showed that Anabaena sphaerica Bornet Flanault possessed the best adaptation to pH changes. It could be more active in 511 pH values.A. vaginicola F.E. Fritsh Rich andA. variabilis Kutzing ex Bornet Flanault were remarkable for salinity tolerance. They adapted to salinity stress up to 2% salt concentrationin the medium. Our results indicated that the growth of all strains decrease by 4% salt concentration and pH 11. Indeed, Anabaena is a cyanobacterium with nitrogenfixation ability and high potency of adaptation to environmental stress. So, it canbe a useful candidate for biofertilizer in agriculture, particularly in rice fields.