Figure 6.

Contribution of photoinhibition-related nonphotochemical quenching (qI) to total nonphotochemical quenching (qN) after high-light stress. Plants were grown under normal light conditions (120 μmol m⁻² s⁻¹) and dark adapted for 15 min prior to the experiment. The plants were then exposed to the high-light stress (1,000 μmol m⁻² s⁻¹) for 10 min (A) or 60 min (B). After the end of high-light stress, total qN was measured (black bars). After an additional dark exposure of 15 min, the rapidly reversible qE-type component of qN relaxes completely, so that the residual proportion of qN remaining after 15 min in darkness is attributable to the PSII photoinhibition qI (white bars). WT, Wild type.