Further Studies on the Effect of Infra-Red Radiation on X-Ray-Induced Chromatid Aberrations in Tradescantia

Abstract

Expts. were under-taken to determine the time limit within which X-ray-induced breaks in the chromosomes of dividing cells restitute or recom-bine non-homologously. The use of infra-red radiation for modi-fying the rate of aberrations was applied to Tradescantia microspores, a time interval of 21 hrs. being imposed between X-rad-iation and chromosome fixation. Metaphase figures were scored for induced aberrations. Treatment with infra-red at any time interval after X-ray up to fixation showed significant increases in exchange aberrations. Somewhat less marked increases are also recorded for single and double deletions at all time intervals except at 4- and 18-hr, intervals in the case of double deletions.