## 3 Results
### Changes in the Leaf LRU, \(\rm g_{s}\), \(\rm F_{C,COS}\) and \(\rm F_{C,CO_{2}}\)  
The meta-analyses showed that there were significant differences in the LRU between the groups categorized by time scale, which reflected the tendency of environmental conditions (\(\rm Q_{b,Hedges^{\prime}d}<0.01\)). Furthermore, no significant discrepancy was observed between the groups at the same time scales (\(\rm Q_{b,Hedges^{\prime}d}=0.56\)) (Figure 4a). Under the aforementioned environmental condition changes, the LRU decreased in the \"Total\", \"Control\" and the N vs. ME groups among the groups categorized by time scale, which was significantly stronger in the NLF, MXF and \(\rm CPL_{C3}\) biomes. Solely on the aspect of light intensity, the decrease of LRU was noticed in the lower light \"control\" group. Moreover, no significantly different LRU responses among biomes were obtained (\(\rm Q_{b,Hedges^{\prime}d,biomes}=0.12\)) in response to environmental condition changes. A change in the LRU was associated with enhanced \(\rm g_{s}\) due to stomatal opening in all the groups, except the daily time scale group. Although no significant differences were found between biomes (\(\rm Q_{b,Hedges^{\prime}d,biomes}=0.73\)), the \(\rm g_{s}\) in MXF, \(\rm CPL_{C3}\) and \(\rm CPL_{C4}\) showed the strongest response to environmental condition changes (Figure 4b). For the photosynthetic gas fluxes, no significantly different \(\rm F_{C,COS}\) responses to environmental condition changes were found between the groups categorized by time scale (\(\rm Q_{b,Hedges^{\prime}d}=0.44\)). After experiencing the strongest variation of VPD, \(\rm C_{a,COS}\) and \(\rm C_{a,CO_{2}}\) (Figure 3d-f), \(\rm F_{C,COS}\) was diminished in most samples of N vs. ME, FA vs. DD, D vs. N and \"Total\" groups; meanwhile, only in N vs. ME was this decrease significant. The diminished \(\rm F_{C,COS}\) was also found in the NLF, BLF, GRA and \(\rm CPL_{C3}\) biomes. In contrast, in the biomes of MXF, MSH and \(\rm CPL_{C4}\), \(\rm F_{C,COS}\) was found to have increased. At the same time, significantly different \(\rm F_{C,COS}\) responses were found between biomes (\(\rm Q_{b,Hedges^{\prime}d,biomes}=0.00\)) (Figure 4c). Moreover, no significant differences in the \(\rm F_{C,CO_{2}}\) response were found between the different temporal groups (\(\rm Q_{b,Hedges^{\prime}d}=0.74\)). \(\rm F_{C,CO_{2}}\) decreased significantly in all the N vs. ME, FA vs. DD, D vs. N and \"Total\" groups, whichreflected \(\text{F}_{\text{C,CO}_{2}}\) diurnal variations. Significantly different \(\text{F}_{\text{C,CO}_{2}}\) responses were found between biomes (\(\text{Q}_{\text{b,Hedges}}\text{d,biomes}=0.00\)). In NLF, BLF, GRA and \(\text{CPL}_{\text{C3}}\), the environmental conditions had an evident negative impact on \(\text{F}_{\text{C,CO}_{2}}\). However, \(\text{F}_{\text{C,CO}_{2}}\) increased in MXF and MSH under the same environmental conditions variation (Figure 4d). Figure 3: _Cont._  
Figure 4: _Cont._  
Figure 3: Environmental condition changes between the control and the treatment groups in each study. Boxes (dots) and the error bars represent the average changes in environmental conditions and the extent of these changes. The number next to the dots is the sample size for each variable. (**a**) LI, the light intensity (\(\mu\)mol m\({}^{-2}\) s\({}^{-1}\)); (**b**) temperature, the atmospheric temperature (°C); (**c**) rH, the relative humidity (\(\%\)); (**d**) VPD, the vapor pressure deficit (Pa); (**e**) C\({}_{\text{a,CO}}\), the atmospheric CO\({}_{2}\) concentration (ppt); (**f**) C\({}_{\text{a,CO}}\), the atmospheric COS concentration (ppm).