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, 2012b ) demonstrated that at temperatures of 20 °C/16 °C (day/night), lettuce plants under 400 and 600 μmol·m −2 ·s −1 exhibited high photochemical quenching (qP), ETR, and yield, as well as moderate nonphotochemical quenching parameter (NPQ) values

'). In this article, we used the definitions of fluorescence parameters [maximum quantum yield of the PSII (F v /F m ), effective quantum yield of the PSII ( Φ PSII), electron transport rate (ETR), and nonphotochemical quenching (NPQ)] as described by

transfer rate (ETR). ( H ) Nonphotochemical quenching (NPQ). Traits that reflect the health of the light-harvesting system (PSII efficiency or Ф PSII and ETR) for the different cultivars displayed trends similar to those observed in A. However, these

( Dannehl et al., 1996 ). In this study, it can be found that the decreased q P is consistent with the decrease of P n ( Fig. 7 ). The q N is an important nonphotochemical quenching parameter, reflecting the changes in the plant heat dissipation

differences were found in relative quantum efficiency of PSII photochemistry (ΦPSII) among Al concentration of 0.5, 1.25 m m, and the control. The nonphotochemical quenching (NPQ) was greatest in the 2.0 m m , followed by those in the control and 0.5 m m Al

-harvesting pigments by channeling photons to the photosynthetic reaction center and functioning as photoprotectants by quenching damaging free radicals or through active nonphotochemical quenching of excess light energy ( Croce et al., 1999b ; Niyogi, 1999

the photosystems under high-light conditions ( Powles, 1984 ). Carotenoids function to dissipate excessive energy or excitation nondestructively as heat, a phenomenon being called nonphotochemical quenching (NPQ) of chlorophyll a fluorescence

under greater PPFD levels or continuous light ( Bian et al., 2016 , 2018 ). Specifically, under greater PPFD s, nonphotochemical quenching could be engaged in upper leaves, whereas in lower leaves, penetrating green light could drive photosynthesis

0 ), photochemical quenching coefficient (q p ), PSII photochemical maximum quantum efficiency (F v /F m ), chlorophyll fluorescence nonphotochemical quenching (NPQ), and actual quantum yield of PSII photochemistry (Φ PSII ). The specific measurement

efficient light harvesting to a state of high thermal energy dissipation, which is usually measured as a nonphotochemical quenching of chlorophyll fluorescence ( Havaux et al., 2007 ). Zeaxanthin can modulate blue-light-dependent responses in plants and is