Effects of radiations on blue-green algae II. Effects in growth

Abstract

The unicellular blue-green alga Anacystis nidulans was repeatedly treated with X-rays and radiophosphate (32P) during successive subcultures. The strains so obtained were characterized by comparison with the untreated control strain, with respect to their resistance to ultraviolet light, X-rays, streptomycin, and isoniazid. The ³²P-treated strain was found to be relatively more resistant to streptomycin than the untreated strain and the X-rayed strain was found to be relatively rnore sensitive to isoniazid than the control. In old cultures, cells of the X-rayed strain were significantly smaller than those of the untreated strain. The effects of X-rays on cell- and heterocyst dimensions of the nitrogen-fixing alga Chlorogloea fritschii Mitra were studied. In the irradiated material the cell diameter and heterocyst breadth were greater, rather than smaller, than in unirradiated material.