Figure 1.

Effects of heat (42°C) or chilling (4°C) temperature on the accumulation of H₂O₂ in the leaves of wild-type (WT) and ΔndhCKJ tobacco plants. Petioles were steeped in solutions containing 1 mg mL⁻¹ DAB (pH 3.8) at 25°C in the dark for 1 h to take up the stain. Samples were then incubated at 25°C, 42°C, or 4°C, under illumination at 100 μmol photons m⁻² s⁻¹. H₂O₂ accumulation was detected as brown areas after 3 h (A and B) and after 1 h (C) of treatment.