Xanthophyll cycle modulation.

<p>Evolution of diatoxanthin (Dt)/chlorophyll (Chl) <i>a</i> (in mol Dt/100 mol Chl <i>a</i>) over the light gradient, in <i>Pseudo-nitzschia multistriata</i> cells experiencing light gradual increases peaking at the PFD of 100, 250, 350, 500 and 650 µmol photons m⁻² s⁻¹, during the 5 h (A), 3 h (C) and 2 h kinetics of light increase (E). Values are means ± SD (<i>n</i> = 3). Relationship between Dt and diadinoxanthin (Dd)/Chl <i>a</i> (in mol pigment/100 mol Chl <i>a</i>), during the 5 h (B), 3 h (D) and 2 h kinetics of light increase (F). In (B) and (F) data measured at PFD ≤350 µmol photons m⁻² s⁻¹ (black dots, <i>n</i> = 39) and ≥500 µmol photons m⁻² s⁻¹ (white dots, <i>n</i> = 6) are discerned. In (D) data measured at PFD ≤250 µmol photons m⁻² s⁻¹ (black dots, <i>n</i> = 33), at 280 and 350 µmol photons m⁻² s⁻¹ (grey dots, <i>n</i> = 6), and at PFD ≥500 µmol photons m⁻² s⁻¹ (white dots, <i>n</i> = 6) are discerned.