SENSITIVITY OF TWO ECOTYPES OF ARABIDOPSIS THALIANA (Cvi AND Te) TOWARDS UV-B IRRADIATION

The susceptibility of Arabidopsis thaliana towards the detrimental effect of UV-B irradiation was investigated using two ecotypes, Cvi and Te. The effect of UV-B treatment on primary photosynthetic reactions - energy interaction between the main pigment-protein complexes and oxygen evolution, was evaluated at low (4 degrees C) and at room (22 degrees C) temperature. UV-B-induced alterations of investigated photosynthetic reactions are better expressed at 22 degrees C than at 4 degrees C for Cvi. For Te ecotype the energy interaction was suppressed to higher extent at 22 degrees C, while oxygen evolving activity was affected similarly at both temperatures. At low and room temperature, the energy interaction in the complex PSII-core antenna is affected stronger by UV-B treatment than the energy distribution between both photosystems, as revealed by fluorescence ratios of 77 K spectra. The results presented indicate that the Arabidopsis thaliana ecotype Cvi (Cape Verde Islands) is less affected by UV-B irradiation in respect to the investigated primary photosynthetic reactions than the ecotype Te (Finland).