Figure 10.

Sustained NPQ accumulates when PSII photoinactivation outruns repair. Accumulated NPQ_s plotted versus the ratio of the photoinactivation rate constant for PSII (k_π) and the PsbA removal rate contant, for T. pseudonana cells grown at 30 μmol photons m⁻² s⁻¹, 12°C (open circle), 18°C (open upward triangle, diamond, downward triangle), or 24°C (open square) and C. radiatus cells grown at 18°C (closed upward triangle, diamond, downward triangle) or 24°C (closed square). NPQs and rate constants were estimated from samples taken during 90 min of exposure to 450 μmol photons m⁻² s⁻¹ blue light (circles, upward triangles, squares) or 450 μmol photons m⁻² s⁻¹ red light (diamonds), or 1,400 μmol photons m⁻² s⁻¹ white fluorescent light (downward triangles). n = 3 to 5, ±se for both x and y axes. Dotted line shows linear regression, R² = 0.62.