Fig. 1

The overall scheme of the experiment. The leaves from 6 week old Arabidopsis thaliana were detached either from dark adapted overnight plants or directly from plants growing in the growth chamber during the light period (2 h after the photoperiodic light had been turn on). The leaves were put on petri dishes on water-soaked paper. Half of each leaf was covered with black paper (control) and the leaves were irradiated with UV-B (8 W·m⁻²) for 5 min. After irradiation the leaves were either left in darkness (leaves from dark-adapted plants) or under continuous illumination with white light (100 μmol ·m⁻²· s⁻¹) for up to 4 days. Thus, 4 different kinds of samples were analyzed, i) darkened control (CD), ii) control illuminated with continuous light (CL), iii) UV-B irradiated leaves left in darkness (UVD) and finally, iv) UV-B irradiated leaves kept under continuous illumination (UVL)