## 2 Materials and Methods
### Experimental Design
#### 2.2.1 Synchronous Measurements of CO\({}_{2}\) and Temperature Curve
Maximal fluorescence emissions in the dark-adapted and light-adapted states (F\({}_{\text{m}}\) and F\({}_{\text{m}}\)\({}^{\prime}\)) from PAM were also collected for 45 s and were used to calculate the required photosynthetic parameters, including NPQ and the photochemical quantum yield of PSII (\(\Phi_{\text{PSII}}\)), which are expressed as [32; 33]  
\[\text{NPQ}=\frac{\text{F}_{\text{m}}-\text{F}_{\text{m}}^{\prime}}{\text{F}_{ \text{m}}^{\prime}} \tag{1}\]  
\[\Phi_{\text{PSII}}=\frac{\text{F}_{\text{m}}^{\prime}-\text{F}_{\text{s}}}{ \text{F}_{\text{m}}^{\prime}} \tag{2}\]  
The net CO\({}_{2}\) assimilation rate (\(A_{\text{net}}\), \(\mu\)mol m\({}^{-2}\) s\({}^{-1}\)) and stomatal conductance to water vapor (\(g_{\text{sw}}\), mol m\({}^{-2}\) s\({}^{-1}\)) provided by the gas exchange system were automatically stored every 5 s. Leaf-scale gross CO\({}_{2}\) assimilation (\(A_{\text{G}}\), \(\mu\)mol m\({}^{-2}\) s\({}^{-1}\)) was obtained from gas exchange measurements:  
\[A_{\text{G}}=A_{\text{net}}+R_{\text{d}} \tag{3}\]  
where \(R_{\text{d}}\) is dark respiration (\(\mu\)mol m\({}^{-2}\) s\({}^{-1}\)) measured in a period of darkness. All measured variables and related equipment are listed in Table 1. For the temperature response curves, leaf respiration was estimated by using the global polynomial respiration-temperature model [34]. To ensure that the gas exchange and fluorescence conditions were stable, measurements for CO\({}_{2}\) and temperature curves were performed after waiting at least 5 min between CO\({}_{2}\) changes, and after waiting at least 10 min between temperature changes, respectively. We then extracted spectral radiance immediately before the saturation pulse as the steady-state spectral measurements. \begin{table}
\begin{tabular}{c c c} \hline
**Measured** & **Definitions** & **Related** \\
**Variables** & & **Equipment** \\ \hline \(A_{\text{net}}\) & leaf net CO\({}_{2}\) assimilation (\(\mu\)mol m\({}^{-2}\) s\({}^{-1}\)) & LI-6800 portable \\ \(R_{\text{d}}\) & leaf dark respiration (\(\mu\)mol m\({}^{-2}\) s\({}^{-1}\)) & gas exchange system \\ \(A_{\text{G}}\) & leaf-scale gross photosynthetic CO\({}_{2}\) assimilation estimated from the gas exchange system (\(\mu\)mol m\({}^{-2}\) s\({}^{-1}\)) & LI-6800 portable \\ \(g_{\text{sw}}\) & stomatal conductance to water vapor (mol m\({}^{-2}\) s\({}^{-1}\)) & gas exchange system \\ F\({}_{\text{m}}\) & maximum fluorescence yield induced by a saturation pulse in the dark-adapted state & DUAL-PAM-100 \\ F\({}_{\text{m}}\)\({}^{\prime}\) & maximum fluorescence yield induced by a saturation pulse in the light-adapted state & fluorometer \\ F\({}_{\text{s}}\) & steady-state fluorescence yield from PAM & DUAL-PAM-100 \\ \(\Phi_{\text{PSII}}\) & photochemical quantum yield of PSII & fluorometer \\ NPQ & nonphotochemical quenching & DUAL-PAM-100 \\ TChIF\({}_{760}\) & the total chlorophyll fluorescence radiance emitted from both abaxial and & QEpro spectrometer \\ \end{tabular}
\end{table} 
Table 1: Measured variables and related equipment used in this study.