FIGURE 1.

Electron paramagnetic resonance (EPR) spin-trapping spectroscopy measurements of H₂O₂(A,B) and ${\mathrm{O}}_{\mathrm{2}}^{\mathrm{•–}}$(C,D) production by illuminated thylakoids isolated from water-treated Arabidopsis thaliana and Eutrema salsugineum. (A) The intensity of EPR signal of H₂O₂-derived hydroxyl radicals; (B) representative EPR spectra of the POBN adduct; (C) The intensity of superoxide anion radical measured with DMPO-OOH spin-trap; (D) representative EPR spectra of the DMPO adduct. The analyses were performed in the presence and absence of sodium azide (NaN₃). ‘Asterisk’ indicates significant difference from A. thaliana. Each data point represents the mean ± SD (n = 3). Significant differences between the averaged H₂O₂ production with and without NaN₃ in both species are not marked on the graph.