## 3 Results
### Relationships between ChlF Parameters and Solar PPFDs  
We examined the relationships between the PPFD and ChlF parameters of \(\Phi_{\rm PSII}\), NPQ, and ETR using PAM and FLD-LISP methods for paprika, maize, and pachira plants. The details of the measurement conditions, the number of samples, SPAD values, temperature of the abaxial side of the leaf, and solar PPFD are summarized in Table 1. The experiments were performed under steady weather conditions. Figures 4-6 present the results for the FLD-LISP measurements. The results of the PAM method exhibited very similar trends hence they were not presented in the plots. We also examined the relationships between SPAD values and ChlF parameters retrieved from FLD-LISP; no significant relationships were found confirming that the ChlF parameters are not affected by Chl content.  
For the three plant species of paprika, maize, and pachira, the results of the relationships between \(\Phi_{\rm PSII}\), NPQ, and ETR and PPFDs using the FLD-LISP method are presented in Figures 4-6, respectively, while the R\({}^{2}\) values of the two methods are given in Table 1. As the solar PPFDs increased, \(\Phi_{\rm PSII}\) decreased whereas NPQ increased exhibiting linear correlations for all three plant species, except that pachira's NPQ was over 1000 \(\upmu\)mol m\({}^{-2}\) s\({}^{-1}\) (Figures 4A,B-6A,B, respectively). Compared to paprika, the \(\Phi_{\rm PSII}\) and NPQ showed less variations for maize. The NPQ/PPFD relationship for pachira was non-linear, experiencing a sharp increase after the PPFD of about 1000 \(\upmu\)mol m\({}^{-2}\) s\({}^{-1}\).  
For ETR, increasing trends were observed when the intensities of solar light were lower than about 800 \(\upmu\)mol m\({}^{-2}\) s\({}^{-1}\) for paprika (Figure 4C), lower than about 1200 \(\upmu\)mol m\({}^{-2}\) s\({}^{-1}\) for maize (Figure 5C), and lower than about 800 \(\upmu\)mol m\({}^{-2}\) s\({}^{-1}\) for pachira (Figure 6C). In contrast, at solar light intensities greater than that stated above, ETR showed a lot of dispersions and the regression lines began to deteriorate.  
Figure 3: Relationships between light pulse PPFD and ChlF yield (\(\Phi\)F: near 760.4 nm) of paprika leaves. (**A**) results in the dark-adapted leaf (SPAD value of 47.5, measured by SPAD-502, Soil and Plant Analyzer Development, Konica Minolta, Tokyo, Japan) measured three times (\(\Phi\)F1 to \(\Phi\)F3); (**B**) results in the light-adapted leaf (SPAD value of 42.6) measured twice (\(\Phi\)F1 and \(\Phi\)F2) at solar PPFD of 700 \(\upmu\)mol m\({}^{-2}\) s\({}^{-1}\) and four times (\(\Phi\)F3 to \(\Phi\)F6) at 1300 \(\upmu\)mol m\({}^{-2}\) s\({}^{-1}\). The JUNIOR PAM actinic light system was used as the light pulse source. Dashed lines represent the minimal PPFD for the saturation light pulse.  
\begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline  
**Paprika** & & & & & & & \\
**PAM** & & & & & & & \\
**FLD-LISP** & & & & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Experimental conditions of the three plant species and the coefficients of determination (R\({}^{2}\)) between ChIP parameters (\(\Phi_{\text{PSII}}\), photochemical yield of photosystem II; NPQ, non-photochemical quenching; and ETR, photosystem II-based electron transport rate) and solar PPFD using the PAM and FLD-LISP methods.  
Figure 4: Relationships between solar PPFD and ChlF parameters (**A**) \(\Phi_{\text{PSII}}\); (**B**) NPQ; and (**C**) ETR of paprika leaves estimated by the FLD-LISP method. The results of the PAM method were very similar and the details are given in Table 1.  
Figure 5: Relationships between the solar PPFD and the ChlF parameters (**A**) \(\Phi_{\text{PSII}}\); (**B**) NPQ; and (**C**) ETR of maize leaves estimated by the FLD-LISP method. The results of the PAM method were very similar and the details are given in Table 1.