Abstract
This study presents the effects induced by X-rays, medium doses (20-70 Gy), over the meristematic tissues of three cereal species: one of barley and two of wheat. The cytogenetic investigation was based on the response of young seedlings during their very early ontogenetic stages to the ionizing radiation exposure. The study was focused on the identification and counting of the chromosomal aberrations for various doses compared to the control samples. Qualitative evaluation revealed: interchromatidian bridges, expulsed chromosomes or chromosome fragments, and complex aberrations (combination of the already mentioned ones). The different behavior of these three species was discussed over the mitotic index, the number of abnormal ana-telophases and over the percentages of the mitosis phases. In each case, the mitotic index was increased in comparison with the control, and also the number of aberrations was found increased; however no evident mathematical correlations with applied doses could be established.