THE RESPONSE OF 3 STRAINS OF ANACYSTIS-NIDULANS (CYANOBACTERIA) TO ULTRAVIOLET-B RADIATION

The influnce of UV-B irradiance was examined on three strains of a cya nobacterium, Anacystis nidulans. These include wild type A. nidulans ( A(n)) and strains resistant to cadmium (Cd-r) and cyanophage As-1 (As- 1(r)). The results indicated that although, the UV-B radiation conside red in the present study was damaging to all the three strains, As-1(r ) offered some degree of protection from W-B as far as changes in chlo rophyll, phycocyanin, (CO2)-C-14 uptake and photosynthetic O-2 evoluti on were concerned. Cadmium resistant strain appeared to be most sensit ive to UV-B among the three. The observations form the first report of UV-B effects on a metal resistant and a cyanophage resistant strain o f cyanobacterium.