Effect of EDTA on the Rejoining of Chromosome Breaks Induced by X-raying

Abstract

Several investigators have indicated that two kinds of radiation-induced chromosome breaks (rapidly and slowly rejoining breaks) can be distinguished on the basis of their average time of restitution. In order to obtain further insight as to whether the rapidly rejoining breaks are of ionic nature or not, the effects of EDTA on the rejoining of the X-ray-induced chromosome breaks were investigated with the root tips of Vicia faba. The results obtained showed that the pre-irradiation treatment with EDTA gave the significantly higher frequencies of both chromatid exchanges and chromatid breaks than those in the X-ray control, whereas the post-irradiation treatment with this chemical did not result in any increase in the frequency of aberration yield. These results indicate that EDTA affects on mainly the rejoining process between the rapidly rejoining breaks and thus they are of ionic nature.