At the presence of DCMU, an inhibitor blocking the electron
transport from Q
A to Q
B (Fig. 6A), the qP in leaves was very low,
and the chilling–light treatment severely decreased Fv/Fm but
had little influence on DI/Io in leaves at different development
stages (Fig. 6B and C). The linear relationship between Fv/Fm and
DI/Io no longer existed in leaves pretreated with DCMU