DIFFERENTIAL RESPONSE OF 2 SPECIES OF THE CYANOBACTERIUM ANABAENA TO ULTRAVIOLET (UV-C) IRRADIATION

Ultraviolet sensitivity of two different species of Anabaena, Anabaena doliolum and Anabaena sp. was studied. These two species differ in th eir pigment composition; A. doliolum showed predominance of phycocyani n whereas Anabaena sp. showed predominance of phycoerythrin pigments. Survival of the two species were different after exposure to different doses of UV (lambda(mot) 254 nm) irradiation; Anabaena sp. was more r esistant to higher UV dose than A. doliolum. In both species the UV in duced damage was partially repaired by white fluorescent light. A. dol iolum showed a lower rate of photorecovery than Anabaena sp.. Higher U V dose (20 min) induced production of a non-nitrogen fixing strain of A. doliolum and a pigment mutant lacking phycoerythrin of Anabaena sp.