Changes in Prompt Chlorophyll Fluorescence and Oxygen Evolution after Bean Plant Treatment with Artificial Acid Rain

The effects of artificially applied acid rain on functional activity of PS2 and oxygen evolution of bean plants (Phaseolus vulgaris L.) were investigated. The plants were subjected to single treatment with acid rain of different pH – pH 5.6 (control) and 2.4, 2.2, 2.0 and 1.8. Measurements were carried out in dynamics – at time intervals of 3–168 hours. The results showed that the treatment of plants with pH 2.4 and 2.2 did not change significantly initial (F0) and variable (Fv) chlorophyll fluorescence as well as Fv/F0 and Fv/Fm ratios characterizing the efficiency of PS2. Most important changes were established in plants sprayed with pH 1.8 cocktail. A similar trend was found in oxygen evolution measurements. It remained about 50% lower in plants treated with pH 1.8 in comparison with the control. We postulate that single treatment of bean plants with simulated acid rain caused considerable changes both in PS2 functional activity and oxygen evolution, but they were still reversible, although to a different extent.