## 3 Results
### The Dependent Variables as Regulated by Environmental Conditions  
On the groups categorized by diurnal cycling (N vs. ME, FA vs. DD, D vs. N), the dependent variables (such as LRU, g\({}_{\rm s}\), F\({}_{\rm C,COS}\) and F\({}_{\rm C,CO_{2}}\)) were regulated by the environmental conditions (light intensity, temperature, rH, VPD, C\({}_{\rm a,COS}\) and C\({}_{\rm a,CO_{2}}\)). Of the environmental conditions, the LRU was significantly influenced by variations in light intensity (R\({}^{2}\) = 1, \(p\) = 0.002), VPD (R\({}^{2}\) = 0.885, \(p\) = 0.005), C\({}_{\rm a,COS}\) (R\({}^{2}\) = 0.58, \(p\) = 0.05) and C\({}_{\rm a,CO_{2}}\) (R\({}^{2}\) = 0.97, \(p\) = 0.003) (Figure 5a-f). There was an exponential relation between  
Figure 4: The averages of Hedges\({}^{\prime}\)d and LnRR, with its’ 95% confidence intervals (CI) of the dependent variables in each group. In the subfigures, dependent variables are (**a**) LRU, (**b**) g\({}_{\rm s}\), (**c**) F\({}_{\rm C,COS}\), (**d**) F\({}_{\rm C,CO_{2}}\), separately. The control and and treatment samples are shown in Tables S2 and S3. If the 95% CI does not include 0, the dependent variables were significantly affected by the change in environmental conditions between the control and the treatment. The dashed vertical line indicates Hedges\({}^{\prime}\)d (LnRR) = 0. The number next to the dots is the sample size for each variable. light intensity and the LRU (Figure 5a). On the other hand, increased VPD reduced the LRU (Figure 5d). As \(\mathrm{Ca}_{\mathrm{a,COS}}\) increased, the LRU increased until a certain turning point of \(\mathrm{Ca}_{\mathrm{a,COS}}\) and then decreased. The regression suggested the LRU saturation point could be \(\Delta\mathrm{Ca}_{\mathrm{a,COS}}\approx 13\) ppt (Figure 5e). In contrast, between LRU and \(\Delta\mathrm{Ca}_{\mathrm{a,CO_{2}}}\), the LRU saturation point could also be \(\Delta\mathrm{Ca}_{\mathrm{a,CO_{2}}}\approx-18\) ppm (Figure 5f). As shown by the linear regression of the change in environmental conditions to \(\mathrm{g}_{\mathrm{s}}\), the stomata were opened significantly only by light intensity (\(\mathrm{R}^{2}=0.58\), \(p=0.01\)) (Figure 6a). Figure 5: Relationship of the Hedges\({}^{\prime}\) d of the LRU with the variation in environmental conditions in the diurnal cycling groups. Subfigures **(a–f)** denote the linear regression between the Hedges\({}^{\prime}\)d value of LRU and **(a)** Alight intensity, the change in light intensity (\(\mathrm{\mu mol}\)\(\mathrm{m}^{-2}\)\(\mathrm{s}^{-1}\)); **(b)** Atemperature, the change in environmental temperature (\(\mathrm{{}^{\circ}C}\)); **(c)**\(\Delta\)rH,  
The fitted F\({}_{\text{C,COS}}\) increased significantly with a decrease in light intensity and was significantly decreased with a slight increase in light intensity (R\({}^{2}\) = 0.23, \(p\) = 0.01) (Figure 7a,b). Figure 6: Relationship of the Hedges’d of the g\({}_{\text{s}}\) with the variation in environmental conditions in the diurnal cycling groups. Subfigures (**a–f**) denote the linear regression between the Hedges’d value of g\({}_{\text{s}}\) and (**a**) \(\Delta\)light intensity, the change in light intensity (\(\mu\)mol m\({}^{-2}\) s\({}^{-1}\)); **(b**) \(\Delta\)temperature, the change in environmental temperature (\({}^{\circ}\)C); (**c**) \(\Delta\)rH, the change in rH (%); (**d**) \(\Delta\)VPD, the change in vapor deficit (Pa); (**e**) \(\Delta\)C\({}_{\text{a,CO}_{2}}\), the change in C\({}_{\text{a,CO}_{2}}\) (ppt); (**f**) \(\Delta\)C\({}_{\text{a,COS}}\), the change in C\({}_{\text{a,COS}}\) (ppm). In addition, \(\rm F_{C,CO_{2}}\) decreased linearly with increasing temperature (R\({}^{2}\) = 0.80, \(p\) = 0.00) (Figure 8b). In terms of moisture conditions, \(\rm F_{C,CO_{2}}\) increased linearly with increasing \(\rm rH\) (R\({}^{2}\) = 0.83, \(p\) = 0.00) (Figure 8c). However, at the canopy boundary layer, the change in VPD did not show any significant correlation with either flux (Figures 7d and 8d).