Oxidative stress, described as an imbalance between the concentration of reactive oxygen species (ROS) and antioxidants, is one of the most important mechanisms of stressors’ action on plants. On the other hand, similar plants’ response to different stress factors and oxidative stress induced increase in the activity of antioxidative enzymes triggers plants’ adaptation to the particular stressor, as well as cross-adaptation to different stress factors. The aim of the dissertation research is to investigate the impact of different stress factors (ozone, UV-B radiation, drought and heavy metals) on growth and intensity of oxidative stress of spring barley, and to estimate the role of oxidative stress and antioxidative system on plants resistance and cross-adaptation to different stress factors. It was detected, that oxidative stress is the major cause of plant’s growth reduction induced by similar stress factors (heavy metals), whereas the specific impact of stressors is low. When plants are exposed to different stressors (drought, ozone, UV-B radiation, heavy metals Cd and Cu), the impact of their specific action increases, however, oxidative stress remains the major reason of plants’ growth reduction. The increase in antioxidative protection and the reduction in the intensity of oxidative stress is the reason of plant adaptation to the stressors with strong oxidative features (Cu and ozone); whereas cross-adaptation to the stressors with lower oxidative potential (Cd and UV-B radiation) is determined by the mechanisms, that are not related to oxidative stress directly.