Hydraulic and Economical Traits in Short- and Long-Shoot Leaves of Ginkgo biloba Males and Females
Round 1
Reviewer 1 Report
In this manuscript the authors studied two different leaf types (short vs. long shoots) in males and females of the dioecious tree Ginkgo biloba with regard to differences in leaf functional traits (morphological, anatomical, gas exchange and hydraulic traits). They found strong shoot-based and sex-related heterogeneities in the measured traits. The authors assume, that with increased drought, also influenced by global climate change, male Ginkgoes will grow better due to their greater leaf hydraulic efficiency and gas exchange rates. I have attached a file with my comments.
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Author Response
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Author Response File: 
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Reviewer 2 Report
Review of Forests MS 2231424
General Comments
In the manuscript titled “Hydraulic and economical traits in short- and long-shoot leaves of Ginkgo biloba males and females,” Liu et al. studied the affects of shoot type and sex on the anatomical and physiological characteristics, with an emphasis on those affecting water transport, for ginkgoes growing in an experimental plot. The authors measured a wide variety of factors for the leaves of four trees of each sex in an attempt to address their goals, which “were to (1) determine the differences in hydraulic, anatomical, and economic traits between long shoot and short shoot leaves and (2) test the drought resistance of male and female ginkgoes. Overall, the study seems sound and the authors were thorough in their measurements. It is believed that if the comments below are addressed that the manuscript will be acceptable for publication in Forests.
One of the things that the authors should add to the manuscript are hypotheses regarding the anticipated differences between short shoot and long shoot leaves, as well as the leaves between males and females. The objectives are stated clearly, but what did the authors expect? Those hypotheses should be included after the objectives in the last paragraph of the Introduction.
Starting on line 69 on page 2, the authors state that they based their hypothesis on differences in hydraulics over the length of ginkgo leaves on previous studies that they cited. Most of the species that were studied previously were angiosperms with leaves with closed vascular systems, whereas ginkgo leaves have an open vascular system, which the authors mentioned. However, the authors never stated how the differences in vascular organization could affect the relative resistance to cavitation for leaves of ginkgoes versus leaves of angiosperms.
In the Materials and Methods, the authors state that a nested ANOVA was used instead of a two-way ANOVA to test for differences between tree sex and leaf type because they were not interested in the interactions between the two factors. First, the authors should state that they used a two-factor nested ANOVA. Second, it seems like differences among the factors for P50 and Kleaf should have been determined using a two-way ANOVA. The lack of a statistical difference between the two sexes using a nested ANOVA is misleading and the authors essentially admit this beginning on line 322 in the Discussion. The P50 of long shoot leaves for males seem like they were significantly higher (less negative) than that for any of the other leaves, regardless of sex. Further, the P50 for the short shoot leaves of males is also much lower (more negative) than it is for any of the other leaves. Also, female leaves of short shoots and long shoots clearly did not differ for P50 or Kleaf. The results indicate there is an interaction between the shoot type and sex and the reasons why should be explored by the authors following a two-way ANOVA.
The last major comment is related to the presentation of data. It is assumed that the authors presented the data for the individual leaf types in the figures and for the different sexes in Table 1 because of the statistical method used. However, having the figures and Table 1 is somewhat redundant and, because of the experimental design and questions asked, it is not likely necessary or appropriate to have Table 1. Also, it is not clear why the authors used lowercase letters to indicate significant differences in some figures but not others. Were there no significant differences in Figures 3 and 4? Is that what “n.s.” meant?
Specific comments
1. Abstract, line 19: Add an “s” to “leaves” at the end of the sentence.
2. Abstract, line 21 and Results, line 250: In reference to female leaves the authors stated that “long shoot leaves displayed slightly higher Kleaf and negative P50.” The authors need to explain what they mean by “negative P50” because P50 is always negative. Further, as stated above, it is not likely that there is a difference between short shoot and long shoot leaves for either parameter.
3. Abstract, line 24: “Male exhibited superior” should be changed to “Males exhibited greater.”
4. Introduction, line 43: It seems like “occurs” should be changed to “has been studied.”
5. Introduction, beginning on line 45: The sentence needs to be rewritten particularly beginning with “as well as the smaller leaves…” It does not make sense.
6. Introduction, line 55: An “s” should be added to “tracheid.”
7. Introduction, line 57: The authors state that the “long shoot leaves might have a hydraulic threshold” but it seems like they need to state whether the long shoot leaves have a greater or lesser hydraulic threshold than short shoot leaves.
8. Introduction, sentence starting on line 74: How are dioecious species an essential component of ecosystems if they only make up 5-6% of the plant species? Do they make up a large percentage of the ecosystem biomass?
9. Introduction, lines 81-83: The font should be corrected.
10. Introduction, line 90: “Ginkgo” should be spelled out at the beginning of the sentence.
11. Materials and Methods, line 129: At the end of the sentence, “measurement” should be changed to “measurements.”
12. Materials and Methods, line 130: The wording should be changed from “the leaf water potentials of gas exchange and water potential…” to “the water potentials of leaves used for gas exchange and the wrapped leaves…”
13. Materials and Methods, line 135: The word “common” should be inserted after “less.”
14. Materials and Methods, line 142: The wording should be changed from “of long shoot and short shoot” to “for long shoots and short shoots.”
15. Materials and Methods, line 154: It is not clear what the authors mean by “in the basal to centra.” Please revise.
16. Materials and Methods, line 177: The wording should be change from “extracted at” to “determined for.”
17. Materials and Methods, lines 185-186: If the tracheids are truly oval or approximate an ellipse, it would be more appropriate to multiply the length of the two axes together and take the square root of the product than to take the average of the two axes.
18. Results, lines 205 and 206: The authors stated that tracheid diameter, SD, and VD did not differ between leaf types for males, but what about females? Also, on line 205, “males and females” should be changed to “male and female” and on line 206 “males” should be changed to “male.”
19. Results, line 209: “Leaf” should be changed to “leaves.”
20. Figure 2 legend: The legend should start with “Specific.”
21. Figure 5, panel c: It is not clear how the values for transpiration could be different between leaves of short shoots and long shoots of males. The authors should indicate the specific P-value for the post-hoc tests.
22. Results, line 248: “To be” should be changed to “being.”
23. In the Discussion, the authors should explain how the water potentials of female short shoot leaves could be lower than those of the other leaves if they had the lowest transpiration and the plants all received the same amount of water in the plot. Do female trees have more leaves? Did they use more water earlier in the season?
24. Discussion, line 340: “Its” should be changed to “their.”
25. How many leaves per node were there for each sex?
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 3 Report
Check unit of measure figure 3a.
Author Response
Check unit of measure figure 3a.
Response: We are sorry to make this mistake. We have revised the unit of leaf thickness in Figure 3a. Please see P7, Figure 3a.
Reviewer 4 Report
This paper offers an interesting and comprehensive look into the heterophylly in the Ginkgo biloba species. Despite it being a not entirely new concept, it presents interesting details about the functional differences between two types of leaves and between genders. This subject matter is appropriate for the journal chosen.
The authors have presented their findings in a clear and concise manner, making it easy to follow and understand the results. They have made a convincing case for their approach, and have also included a discussion of potential limitations and future directions.
I recommend accepting paper after making minor revisions.
Specific comments:
Please insert author names after Latin name of plant species throuougt the text.
Lines 43 and 44. This is not completely true. Please rephrase. We have information about heterophylly within Gymnosperms. There is strong tendency of heterophylia within Gymnosperms. (See Meyen, 1984, Leigh et al. 2010)
Author Response
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Author Response File: Author Response.docx
Reviewer 5 Report
1) Scientific name of Ginkgo biloba, Nuphar lutea, etc. should be properly written throughout the manuscript
2) More recent references should be cited
3) Typos, language errors, and grammar should be taken care
4) Statistical details of the table should be given as a footnote and not along with the table titleTable
Author Response
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Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
I really appreciated how you revised your manuscript. However, I would still consider a few suggestions for improvement:
L34-35: I would write "an ecological adaptation" as there is not only one adaptation (=THE).
L77-79: You have to rephrase this sentence. If you write "Although[...]" I would expect: "Although dioecious species ONLY account for 5-6%[...], they play an important role in maintaining the stability and function of terrestrial ecosystems, as many dioecies are pioneer species [...]." However, reading the sentence as you wrote it, it's not getting clear what you want to say.
L93: Delete "." after "Ginkgo"
L353-358: Please be more precise here. Which sex is more prone than the other? What impact can this have on populations?
L359: "Differed" between "was differ". In addition the abbreviation "A" is indeed very short and not intuitive. Maybe better to use "net photosynthesis rate" here and elswhere.
Table S3: There should be also p-value, which you can extract from the nested ANOVA output. Please add these values to the table.
Author Response
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Author Response File: Author Response.docx
