Figure 5.

Photosynthetic Parameters of Mature Wild-Type and pgr5 Plants Measured under Illumination Mimicking the Fluctuating Growth Light Condition.

The plants were grown either under constant moderate light (120 µmol photons m⁻² s⁻¹) or under mildly fluctuating light with 5 min of low light (50 µmol photons m⁻² s⁻¹) and 1 min of moderate high light (350 µmol photons m⁻² s⁻¹) repeating for the entire photoperiod. Col-0, Columbia-0.

(A) to (D) Actinic light that mimics the fluctuating light (5 min of low, 58 µmol photons m⁻² s⁻¹ light, depicted as yellow, and 1 min of high, 533 µmol photons m⁻² s⁻¹ light, depicted as orange) was applied on detached leaves. The values represent means ± sd, n = 4 to 6.

(A) Photochemical quantum yield of PSII.

(B) The relative Q_A reduction level, measured by the chlorophyll a fluorescence parameter F′/F_m.

(C) The PSI redox state.

(D) Induction of NPQ. HL, high light (orange); LL, low light (yellow).