Figure 7.

Changes in PSII effective absorption cross section (σ_PSII), estimated from flash fluorescence rise kinetics, in T. pseudonana (A–C) and C. radiatus (d and E) cultures treated with (closed symbols) or without (open symbols) the chloroplast protein synthesis inhibitor lincomycin. Both species were grown at 30 μmol photons m⁻² s⁻¹ at 12°C (A), 18°C (B and D), or 24°C (C and E), then exposed to 450 μmol photons m⁻² s⁻¹ blue light for 90 min, and then allowed to recover at 30 μmol photons m⁻² s⁻¹ for 30 min. Circles represent σ_PSII measured in the dark, squares represent σ_PSII′ measured under the treatment light of 450 μmol photons m⁻² s⁻¹ blue light. n = 4 to 5 independent culture experiments, ±se; most error bars within symbols. Downward arrows indicate light-driven down-regulation of σ_PSII to σ_PSII′ in T. pseudonana.