Ultraviolet-B radiation (biologically effective dose 2.6 kJ m -2 d -1 ) had negative influence on morphology and physiology of the young triticale plants. Plants exposed to UV-B were of lower height than control plants, their leaves were narrow, and the rate of net photosynthesis was decreased. The line RAH 336, which wax cover is lesser than that of traditional cultivar Magnat, was more susceptible to UV-B radiation, considering primary photosynthesis reactions, recorded by chlorophyll a fluorescence. An activation of protective mechanisms was observed: plants responded to UV-B by an increase of the content of UV-B absorbing compounds, and changes of antioxidant enzyme activities.Additional key words: antioxidant enzymes, catalase, chlorophyll fluorescence, net photosynthetic rate, peroxidase, Triticosecale.

Plants of soybean (Glycine max L.) cv. Augusta grew in the soil with addition of Ni in the concentration of 80 (C-80) or 120 mg•kg -1 dry mass (C-120) or without Ni (C-0), and they were subjected to UV-B (300 nm -315 nm) dose of 1.8 kJ m -2 d -1 for 28 days. The addition of nickel into soil in the concentration of 120 mg kg -1 (C-120) caused a decrease of the plant height by 35% compared to the control (C-0), and in the presence of UV-B (U-120) -by 43%. The shoot fresh and dry mass in the C-80 and C-120 plants were lower by 33% and 52% than in the C-0. In the presence of Ni, the intensity of net photosynthesis decreased by 55%. UV-B caused an increase of flavonoid content by 25% compared to the control (C-0), and Ni induced a reduction in the content of these compounds from 20% to 40%.