Temperature Effects on X-Ray Induced Chromosome Aberrations

EVERAL investigations have shown that the frequency of X-ray induced S chromosome aberrations may be changed by varying the temperature a t which the nuclei are irradiated. Irradiation of Tradescantia microspores a t high temperatures have produced less aberrations than did the sameX-ray dose a t low temperatures (SAX and ENZMANN 1939; FABERGI? 1940; Such results are not attributed to the temperature effect on the incidence of breakage, but to changes in the frequency of new associations of the broken chromosomes. DARLINGTON and LACOUR (1945)~ on the other hand,find no temperature effect on the frequency of X-ray induced chromsome aberrations and attribute the earlier described results to the effect of temperature on the time scale of nuclear development or to changes in the nucleic acid metabolism.