Abstract
The resistance of Streptomyces canosus 71 against γ-, UV- and combined radiation was studied. Under the combined irradiation the frequency of morphological mutations rose strongly as compared with frequency of morphologically changed forms caused by the γ- and UV- rays. The cell death of S. canosus 71 caused by the combined irradiation also increased. Under the influence of combined irradiation the lethal doses were discovered on much lower levels of radiation.