THE EFFECT OF ULTRAVIOLET-B STRESS ON PHOTOSYSTEM II EFFICIENCY IN BARLEY PLANT

This study was conducted to investigate the effect of UV-B radiation with different exposure times (0, 1, 3 and 5 hours) on photosystem II (PSII) efficiency of barley (Hordeum vulgare L., Bülbül 89) leaves. The polyphasic rise (OJIP) in the chlorophyll a fluorescence was used to evaluate the effect of UV-B stress on the efficiency of PSII. UV-B stress significantly affected the functional parametersand structural parameters calculated by JIP-Test. The effect of UV-B with different application times on polyphasic chlorophyll a fluorescence parameters are discussed from the perspective ofevaluating the relative importance of UV-B of donor and acceptor side capacity in PSII.