THE STUDY OF HETEROCYSTOUS CYANOBACTERIA FROM PADDY FIELDS IN KALAT NADERI DISTRICT IN NORTH-EAST OF IRAN

Heterocystous cyanobacteria represent an interesting group of photosynthetic prokaryotes which are capable of n2 fixation and are present abundantly in rice fields. the aim of this study was the identification and purification of cyanobacteria from rice fields in the kalate naderi ,which is located in north-east of khorasan razavi province. to approach this aim, four paddy fields were selected to investigate heterocyestous blue-green algae. in total, 30 taxa were identified. these species belong to genera such as nostoc, anabaena, cylindrospermum and calothrix. among these genera, nostoc was found to be dominant genus in all samples. six species, including anabaena fuellebornii schmidle, anabaena inaequalis bornet & flahault, nostoc pruniforme c. agardh ex bornet & flahault, nostoc amplissimum setchell, nostoc piscinale kützing ex bornet & flahault, and calothrix fusca (kützing) bornet & flahault were identified as new records for iran.