ABSTRACT. Researches were conducted with wheat (Tríticum durum), barley (Hordeum vulgare) and corn (Zea mays indentata) plants irradiated with gamma radiation at different doses. In the studies conducted by Electron Paramagnetic Resonance spectroscopy (EPR) method, some biophysical parameters were studied in control and ten-day-old sprouts of wheat and corn seeds irradiated with different doses of ionizing gamma radiation, and a detailed explanation of the obtained regularities was given. At the same time, cytogenetic analyzes were carried out with seedlings of wheat (Tríticum durum), barley (Hordeum vulgare) and corn (Zea mays indentata) plants irradiated with different doses of ionizing gamma radiation, and chromosomal aberration was determined. The regularity observed in the results obtained during the experiments was explained by the working mechanism of the photorespiration process in plants belonging to the C3 type of photosynthesis. Germination dynamics were determined in the studied plants. Prepared samples were studied on a ZEISS Axio Imagez A2 electron microscope. Compared with control samples, the effect of different doses of ionizing gamma radiation on the mitosis process in plant roots was studied.