Reply on CC2

We would like to thank you for the thoughtful and valuable comments and suggestions on our manuscript entitled “Excess radiation exacerbates drought stress impacts on stomatal conductance along aridity gradients” (bg-2022-50). We have carefully revised our manuscript to take account of your comments and suggestions. Meanwhile, we have rephrased our manuscript title as “Excess radiation exacerbates drought stress impacts on canopy conductance along aridity gradients”.Here are the point-to-point responses (responses in upright Roman in black front) to the comments (original queries in Italic in blue front). The changed figures and tables are presented in the Appendix 1 and Appendix 2 (listed at the end of the “Response to community comment #2”).


2007; Moreno-
) and canopy scales (Cabrera et al. 2021;Hirl et al. 2021), and among communities along soil (Ramirez et al. 2009) and climatic (Keitel et al. 2006) gradients. Consequently, we selected 1/△ 18 O was used as a proxy for g s in this study." 4) There may be interspecific difference in gs, so information on plant species and species composition of the three study sites should be provided.
The species, genera and families of species occurred in each community have been listed in "Supplementary 2" (Please see Appendix 2)".

5)
The headline of the first part in the discussion should be changed, because the patterns of gs among the tree transects are similar, but differ in magnitude. In addition, the authors attribute this difference to the temperature-induced changes in photosynthesis, which I don't agree. Indeed, gs and photosynthesis are closely correlated, for example, to maximize carbon gain and minimize water loss according to the optimal stomatal behaviour. However, in my opinion, the correlation between gs and photosynthesis is regulated by stomatal behaviour.
Response: Thank you very much for your comment. We respond this comment from two aspects.
(1) The headline has been change as: " 4.3 Differences in canopy conductance among transects" .
(2) The effects of VPD, solar radiation and temperature on the differences in canopy conductance among transects have been rephrased as: " Significant differences in community 1/△ 18 O were found among transects, and the order of G s at a given aridity value was LP > MP > TP (Fig.2a). Among transects, only differences in VPD, solar radiation and temperature were significant (P>0.05) ( Fig.1 and  Fig.S1). In general, plants decrease their g s to respond to increasing VPD (Grossiord et al. 2020). While, intercept of linear regression between aridity and community 1/△ 18 O decreased with decreasing VPD among transects (P>0.05) (Fig.3a). It indicated that the difference in VPD was not a contributor to the difference in G s among transects.
We attribute the differences in G s among transects to the direct effects of solar radiation and temperature on G s and photosynthesis (Yu et al. 2002). This is inconsistent with the results within transect. High solar radiation exhibited negative effect on intercept of linear regression between aridity and community 1/△ 18 O among transects (P<0.05) (Fig.3b).
Excess ultraviolet-B radiation (Duan et al. 2008), insufficient thermal dissipation, and enhanced photorespiration under high solar radiation (Cui et al. 2003) can decrease photosynthesis, ultimately reducing g s . For example, Yu et al. (2012) observed that photosynthesis of wheat at leaf level on the TP was lower than that on North China Plain due to the high solar radiation.
Transect with low temperature exhibited low intercept of linear regression between aridity and community 1/△ 18 O (Fig.3c), it indicated that G s among transects also inhibited by low temperature. Generally, photosynthesis and G s increased with temperature below optimum temperature (Xu et al. 2021). For example, photosynthesis of wheat was lower in a cold than in a warm environment (Yu et al. 2002). " 6) line 25 delete "at leaf level".

7) line 24 change "in one" and "in the other" into
Response: Change has been made.

8) I suggest that "interaction effects" may be changed into "interactive effects".
Response: Change has been made.