Fluorescence spectrophotometry
A MINI Imaging PAM instrument (Heinz Walz GmbH, Effeltrich, Germany) was
used to measure the Fv/Fm and
△F/Fm′ of pepper and N. benthamiana leaves. The
plants were adapted to darkness for 15 min and then placed directly into
the instrument for testing according to the method of Schreiber and
Klughammer(U & C, 2013).