Figure 1.

Time course of the development of non-photochemical quenching of chlorophyll fluorescence (NPQ) under 2% O₂ (balance N₂) and 2000 µmol photons m⁻² s⁻¹ at 25 °C. Mean values ± standard deviation, n = 3 or 4, from the leaves of wild-type Col-0 (open symbols) and vte1 (dark gray symbols), npq1 (medium gray symbols), npq4 (light gray symbols), and npq1 npq4 (orange symbols) mutants of Arabidopsis thaliana grown at 35 °C. Differences between Col-0 and the npq1, npq4, and npq1 npq4 mutants at all of the time points were highly significant (p < 0.001; Student’s t-test). There were no significant differences between Col-0 and vte1.