Further cytological studies on G 1 x-rated primary roots of Vicia faba: chromosome aberrations, mitotic frequency, and multiple fixation

Abstract

Soaked seeds of Vicia faba were irradiated with 800 or 400 R, or two 400-R exposures separated by 2 h. Samples from each exposure showed that the chromosome aberration yields varied with fixation time; the source of the variation was due to the inherent properties of the first mitotic cell populations and not to a contamination of first mitotics with second and third mitotics for the exposure regimen. The results indicate that an experiment with but a single fixation time would obviously lead to incorrect estimates of chromosome damage because comparable cells in differently treated specimens may not be in mitosis concurrently; for example, a resistant sub- population of cells may arrive in mitosis at different fixation intervals with different exposures.