The role of exposure intensity on DNA damage issue in low-dose X-ray irradiated plant cells

Complete text of publication follows. Risk assessment of low level-chronic irradiation seems to be the main task of modern radiobiology. The problem is that negative consequences for low-dose irradiated biological systems appeared to be higher then expected one because on the level of damages induced with this irradiation, which c be comparable with the damage level caused with high irradiation dose. The aim of this study is to investigate the dose capacity effects for the induction of DNA damages and their elimination. Effect of radiation capacity may by the most important fac tor for the modification of repair system activities thus it can be also important for the level of DNA damages. Isolated plant cells have been irradiated by X-rays with low doses followed by investigation of DNA single brakes level. Protoplast suspension obtained from different plants species was irradiated with X-rays capacity ranged from 4,2 R/min to 123 R/min. Total absorbed doses were as 10 R, 25 R and 50 R. DNA has been analyzed by hydroxyapatite chromatography and DNA damages monitored during different time intervals. Results obtained had not linear dependence between the level of Experimental results have indicated that value of irradiation pressure upon plant genome during the same time period plays an important role for the induction of additional repair systems and the level of DNA damages after low-level irradiation may be determined by irradiation capacity