EN
Plants growing under natural conditions are constantly exposed to ultraviolet (UV), primarily UV-A, radiation. Grass pea (Lathyrus sativus L.) is a legume species resistant to harsh growing conditions, such as drought, salinity or periodic flooding. Due to the advantageous composition of seeds, it is used for consumption in such regions as South Asia or East Africa where high intensity of UV radiation occurs. Absorption of this spectral range causes changes in the photosynthetic apparatus of plants, including damage to the photosystem II (PSII) reaction centres. The aim of the work was to examine whether the use of the combination UV-A: red light as a source of radiation would enable quick acclimatization of the photosynthetic apparatus of grass pea to the negative effect of UV-A radiation. 14-day-old plants were exposed to UV-A:red radiation for 48 h. The plants exposed to UV-A:red radiation showed enhanced effective efficiency of PSII and increased total electron carriers, which enabled more effective photosynthesis at higher values of radiation intensity in comparison with control plants, kept under white LED light. At the same time, there were no statistically significant differences in both the photosynthetic pigment contents and the level of lipid peroxidation. The obtained results indicate that the observed increase in the efficiency of CO₂ carboxylation after short-term UV-A:red radiation has resulted from the efficient linear electron transport due to maintaining the effective oxygen evolving complex (OEC) and increased total electron carriers.