ACCELERATED DNA SYNTHESIS IN ONION ROOT MERISTEM DURING X-IRRADIATION

Abstract
The effects of various doses of X-rays on synthesis of DNA and on the nucleohistone complex in individual onion root tip cells has been studied using both microspectrophotometric and autoradiographic methods. Cell proliferation is inhibited by X-rays. The process of DNA synthesis, on the contrary, is stimulated during irradiation and continues to the premitotic level in a period of complete mitotic inhibition. The normal cytochemical properties of the nucleohistone complex appear unchanged even after heavy irradiation.