Fig. 3.

Growth in elevated O₂ raises qE-related protein levels and qE capacity, but lowers PsaA and maximum P700⁺ levels in npq4. WT-4A and npq4 were grown on 1.5% agar medium under photoautotrophic conditions in a 17% or 35% O₂ atmosphere for 5 d under a 16/8 h light/dark cycle (250 µmol photons m⁻² s⁻¹). (A) The same protein extracts were used for all five blots. (B and C) Measurements of chlorophyll fluorescence were made after 1.5 h low light recovery, n=4±SD with different letters denoting significant differences (P<0.05). (D) P700-dependent absorption changes in WT-4A and npq4 (see key). The increase in signal during a saturating pulse starting at time 0 corresponds to accumulation of P700⁺. Kinetics were averaged from four biological replicates each measured four times.