Leaf Trait Variations and Ecological Adaptation Mechanisms of Populus euphratica at Different Developmental Stages and Canopy Heights

Comments

Response and Revisions

General Comments: This is a generally very well-written, organized, and developed manuscript. It has some significant weaknesses that I will try to address and suggest answers to.

Thank you for your positive feedback and constructive criticism. We appreciate your detailed review and have addressed the weaknesses you highlighted. We have emphasized the extraordinary role of Populus euphratica in the introduction and referenced relevant literature, such as "Limits of thermal and hydrological tolerance in a foundation tree species (Populus fremontii) in the desert southwestern United States".

Comments 1: Line 16: “Leaf trait variations are critical for plant growth and ecological adaptation.” This sentence is confusing. Do you mean: “A plant’s ability to vary particular combinations of leaf traits during both development and exposure to abiotic stress is key to its success and survival.”

Thank you for this suggestion. We agree with your comment and have revised the sentence to: “A plant’s ability to vary particular combinations of leaf traits during both development and exposure to abiotic stress is key to its success and survival.” This change can be found on line 16.

Comments 2: Lines 16–19: Network analysis has been rare in understanding trait patterns and their combinations, but there has been a lot of work on leaf anatomical and morphological traits in Populus spp.

We appreciate your input. We have clarified this by acknowledging the existing work on leaf anatomical and morphological traits in Populus spp. while emphasizing the novelty of our network analysis approach. The revised text can be found on line 20.

Comments 3: Line 26–27: My concern is the use of the term ‘module’ in this study. Please refer to the literature on modularity in plants.

Thank you for this important point. We have reviewed the suggested literature and refined our use of the term ‘module’ to better align with the established concepts in plant modularity. The updated terminology can be found on line 224.

Comments 4: Line 28: “..the coordination ability between leaf traits …” Coordination ability implies purpose. Consider using “linkages, combinations, or assemblages.”

We agree with your suggestion. We have replaced “coordination ability” with “linkages” to avoid implying purpose. The revised text can be found on line 30.

Comments 5: Lines 41–43: You did not actually drought stress the trees, so you can only infer that these traits and their combinations might confer drought resistance.

You are correct. We have revised the text to clarify that we are inferring that these traits and their combinations might confer drought resistance. The updated text can be found on line 42.

Comments 6: Lines 48 plus: Typically, there are only two stages of development: juvenile and mature. You have created categories based on size classes. Be clear about this.

Thank you for this clarification. We have revised the manuscript to clearly distinguish between structural size classes and developmental stages.

Comments 7: Lines 70–72: Most studies, except some by Isebrands, Ceulemans, and Scarascia-Mugnozza, are not as comprehensive as yours.

We appreciate your acknowledgment of the comprehensiveness of our study. We have included a comparison to the studies by Isebrands, Ceulemans, and Scarascia-Mugnozza to highlight the novelty of our approach.

Comments 8: Line 79: Clarify the abbreviation “LES” by stating “leaf economics spectrum (LES)”.

Thank you for this suggestion. We have clarified the abbreviation “LES” by stating “leaf economics spectrum (LES)” in the text.

Comments 9: Lines 100–118: Very well written and stated.

Thank you for your positive feedback on this section.

Comments 10: Line 129: Clarify the number of trees studied by stating: “Sixty total trees were studied with 12 trees within each diameter class (i.e., 4, 8, 12, 16, and 20 cm dbh).”

We agree with your suggestion and have clarified the number of trees studied as recommended. The revised text can be found on line 143.

Comments 11: Lines 143–144: Twenty leaves were collected from each study tree, and the major leaf veins and leaf margins were excluded from leaf tissue samples.

Thank you for pointing this out. We have clarified the sampling method to ensure it is clear. The revised text can be found on line 166.

Comments 12: Lines 181–185: Put these abbreviations and their definitions into a table for easy referencing by any reader.

We agree with your suggestion. We have created a table for abbreviations and their definitions for easier reference. This table can be found on line 205、678

Comments 13: Line 187: You start with LTN without defining it! Define LTN earlier in the text.

We apologize for this oversight. We have defined LTN earlier in the text to ensure clarity. The revised definition can be found on line 208.

Comments 14: Lines 187–189: Can you state that only reproductive structures were found on trees in specific size classes? See major point #3.

We agree with your comment. We have clarified that reproductive structures were only found on trees in specific size classes. The revised text can be found on line 145.

Comments 15: Line 203: Clarify the use of “modularity” to avoid confusion with the definition of a module.

Thank you for this suggestion. We have revised the text to clarify the use of “modularity” and avoid confusion.

Comments 16: Lines 236–237: Change “With the increase in diameter order …” to “As diameter class increased …”.

We agree with your suggestion and have made the recommended change. The revised text can be found on line 265.

Comments 17: Figure 2: Ensure the figure legend stands alone for clarity.

Thank you for this comment. We have revised the legend of Figure 2 to ensure it can be understood independently of the main text.

Final Thought/Worry: When sampling trees within a size class, how might you assure yourself that the 4 cm size class of trees were not made of a single clone (or single recruitment following periodic flooding)?

Thank you for this important point. We have addressed this concern by including a discussion on the genetic diversity of sampled trees and our sampling methods to ensure representativeness. This discussion can be found on line 141.