Changes in the O₂ uptake rates in thylakoid membranes during 30 min of photoinhibition (A) in the absence (Ctrl) or presence of 1 or 2 mM Spm.

<p>Inset: percentage of photoinhibition in presence of 1 and 2 mM of Spm in thylakoid membranes, from the experiment of Fig. 1A. (B) Comparison of the effect of increasing the Spm and Spd concentration on O₂ uptake rates in thylakoid membranes after 30 min of illumination. Control rate in the dark (Fig. 1A) was 525 µmol O₂ mg Chl⁻¹ h⁻¹, and the results are a mean of 9 assays.