The chlorophyll a fluorescencewas analyzed at 30 DAE using a pulse
amplitude modulated fluorometer JUNIOR-PAM (Walz, Effeltrich,
Germany). The fluorescence was measured in the first fully expanded
leaf in three plants per treatment during the period between 8:00 and
9:30 am (Souza et al., 2013). Prior to the measurements, the leaves
were pre-adapted to the dark for 30 min to assess the initial fluorescence
(Fo). Subsequently, the sample was subjected to a saturating
light pulse (10,000 μmol m−2 s−1) for 0.6 s to assess the maximum
fluorescence (Fm). The PSII maximum quantumyield (Fv/Fm), electron
transport rate (ETR), photochemical quenching (qP), non-photochemical
quenching (NPQ) and PSII effective quantum yield (Y(II)) were assessed
using the fluorescence induction curve