Fig. 1.

Photoprotective role of zeaxanthin bound to PSI. (A) P700 activity measured as P700 oxidation on whole leaves from WT and npq1 plants exposed to strong light (2,000 µmol⋅m⁻²⋅s⁻¹) for 30 min and 90 min. (B) P700 activity measured as P700 oxidation on PSI–LHCI complexes isolated from WT and npq2 upon illumination with strong light (1,000 µmol⋅m⁻²⋅s⁻¹). (C) Photobleaching curves of PSI–LHCI complexes isolated from WT and npq2 plants measured as the decrease of 600- to 750-nm integrated chlorophyll absorption.