ABSTRACT:
Enhanced solar ultraviolet radiation due to ozone depletion is a major stress factor for cyanobacteria in aquatic and terrestrial ecosystems. Therefore to study the impact of UV-B radiation on cyanobacteria, we isolated three genus of blue green algae namely Anabaena spp., Nostoc spp., and Scytonema spp., and were exposed to UV-B at sublethal dose. The UV exposed cyanobacteria were screened analyzed for the specific growth rate, pigments and heterocyst count with wild type strains for a period of 20 days. All UV-B exposed strains were exhibited stunted growth and pigments content except Scytonema spp. It exhibited accelerated growth and increased carotenoids and heterocyst number. This investigation concluded that the UV-B radiation has negative impact on all genus studied except Scytonema spp in which strain improved in many aspects (positive impact). There by high efficiency strains can be generated using UV-B mutation that could potentiate their application as biofertilizer and also for value added products.