Figure 2.

Steady-state non-photochemical quenching (NPQ) and effective quantum yield of photoScheme 5. and/or NTRC, as well as WT (Col-0 and Col-5) control plants, grown under different lighting conditions. (A) NPQ of wild type and mutant (ntrc, pgr5 and pgr5 ntrc) plants grown on different photoperiods (100 µmol photons m⁻² s⁻¹): 8 h light/16 h dark (short-day, 6 week-old plants), 12 h light/12 h dark (5 weeks old), 16 h light/8 h dark (long-day, 3 weeks old), and under different lighting conditions: high light (HL, 500 µmol photons m⁻² s⁻¹, 2 weeks old) and fluctuating light (FL, 50 µmol photons m⁻² s⁻¹ for 1 min and 500 µmol photons m⁻² s⁻¹ for 5 min, 5 weeks old), after 9 min of illumination with actinic light (80 µmol photons m⁻² s⁻¹). (B) Φ_II corresponding to the plants in (A). NPQ and Φ_II averages ± SD values (n ≥ 4) are indicated; signal intensities correspond to the colour scale at the bottom of the panel.