Figure 2.

ROS production by thylakoids from wild type and RNAi-W1-1 and RNAi-W1-7 lines. Thylakoids were prepared from seedlings grown in continuous light of 200 µmol photons m⁻¹s⁻¹. Superoxide/hydrogen peroxide levels were measured by spin trapping EPR using 4-POBN/EtOH/FeEDTA as spintrap and singlet oxygen by the spin probe TEMPD-HCl (for experimental details, see [15]). Thylakoids were illuminated for two minutes with red light (500 µmol quanta m⁻²s⁻¹) in the presence of the chemicals. Left: representative spectra, right: EPR signal sizes (4-POBN/EtOH/FeEDTA) were normalized to the signal obtained in wild-type thylakoids (mean ± SD, n = 6).