Photosynthetic Processes and Light Response Model Fitting of Quercus acutissima Carruth. and Quercus variabilis Bl. in the Changjiang River Delta, China

Round 1

Reviewer 1 Report

I have added a special comment on the Manuscript ID: forests-1995650. The special comments are as follows:

This paper reveals photosynthetic process of Quercus acutissima and Quercus variabilis, and also evaluate the goodness of fit of the three models by using a LI-6400 Portable Photosynthesis System. The photosynthetic process is reliable. The main contribution of the paper is to screen the best model by comparing three models about the photosynthetic light response curves. This paper can make the reader understand the key content, although the language is not very fluent. The conclusions are based on the observation data and are consistent with evidence.

Generally, I think this paper is excellent.However, I suggest to make some necessary minor modifications.

(1)2.1. Site description, it is better to add a distribution map of the research area and sampling sites.

(2)Table4, The ‘N’ of Latitude can be placed in the first line, same as other units.

Author Response

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Reviewer 2 Report

This manuscript studies the carbon fixation capability through photosynthetic process of two tree species, which is an important topic. However, the language needs to be seriously polished. There are many grammatical mistakes, confusing expressions, and messy organizations, which hinders the reading and understanding process of readers. The format is not consistent.

 Title. The title does not convey a clear logic and key message of the research. Suggest “Photosynthetic Process of Quercus acutissima and Quercus variabilis and Three Models Fitting of their Light Responses at the Changjiang River Delta, China”. In addition, carbon fixation capacity is the keyword of the paper, it’s better to include this in the title. Again, the carbon fixation capacity should be the focus of the research, however, it is not well studied.

 Keywords. Those keywords cannot represent the content of the paper.

 Abstract. The abstract is too long and not concise enough. Although we know photosynthesis mainly happens during day time, please add “am” to the specific time.

 Introduction. The logic of the introduction is not clear. The current version cannot lay a solid foundation of the research hypothesis. By the way, the research hypothesis is also not clear.

 Materials and Methods. The methods were overall not well described, lack of details. For example:

How long is the “climate observation”?

How did the author select the tree samples? Which were in early growing season and which were in peak growing season, i.e., the mentioned “different growing periods”?

 Results and discussion should be merged. The current version is too long, not concise enough.

 Conclusion. DON’T repeat the results. Provide more implicative information.

 References. The references are not updated enough.

Author Response

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Reviewer 3 Report

I have some remarks, I would like to inform authors to consider them.

 

1. Please highlight the innovation of the manuscript.

2. The introduction to three models or the previous studies on the application of three models is still lacking in Line 47-57. In other words, the introduction was not enough.

3. How many samples (the data in table 1) did the author take for measurement? Are they representative?

4. Please check the unit of forest age in table 1 is correct.

5. Information such as instrument model and city needs to be supplemented in Line 92-94.

6. What is the weather like when the data is measured? Weather data is available? e.g., light intensity, humidity, air temperature.

7. what is the early growing season and the peak growing season? How to define different periods?

8. How many days of data showed in Figure 1.

9. The significant digits do not need to be reserved as 296.277……because the accuracy is not so high.

10. Whether the data obtained from the literature are referential due to the differences in the weather conditions, growth conditions, etc. (Table 4)

Author Response

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Author Response File: Author Response.docx

Reviewer 4 Report

General comments

I have read the manuscript (forests -1995650). Entitle: Photosynthetic Process and Three Models Fitting of Light Response Curve on Quercus acutissima and Quercus variabilis in the Changjiang River Delta, China written by Cunxin Ruan et. al., for publication of forests MDPI. In this study, the author investigated the forest photosynthetic efficiency, the photosynthetic light response curves of the two above species were fitted by the rectangular hyperbola model (RHM). The author mainly found that all daily variation curves of the net photosynthetic rate, stomatal conductivity, and transpiration rate were single-peaked. The net photosynthetic rate was found to be positively correlated with the stomatal conductivity, transpiration rate, and photosynthetically active radiation, and was negatively correlated with the intercellular CO2 concentration.

The overall research is well conducted, and research is obvious application potential because the maximum net photosynthetic rate, light saturation point, light compensation point, and dark respiration rate were well simulated by the rectangular hyperbola model, non-rectangular hyperbola model, and modified rectangular hyperbola model. The photosynthetic performance of Q. acutissima was superior to that of Q. variabilis, which can be employed as a priority tree species in carbon sink forests. In this sense, this manuscript is much valuable. However, I found some points, especially the flow of the text and lack of potential references, and lack of connection of story in different paragraphs, especially in the introduction and discussion sections. The author should provide enough examples and their interpretation of different traits of physiological responses from a biological perspective by the latest and appropriate references, some of which I mentioned below. Overall after I evaluate and request the author for this manuscript as a “MAJOR REVISION”.

 

Major suggestions

1)     abstract: Author should be concise and present the important result in the abstract because it seems out of word limit. More importantly, the methodology part and instrumentation should not be included in the abstract. The abstract should be short and concise and easily undesirable after the short observation by the readers including the most important home message.

2)     Introduction: Author starts the introduction very well with describe the terrestrial ecosystem and the importance of carbon. However, author is lacking to present the contributing factors for photosynthesis such as leaf area, leaf thickness, and chlorophyll content. These factors contribute a major role in the absorption of light to perform photosynthesis. For example, higher Chlorophyll content higher the chance to convert the light energy into chemical energy and increase the leaf thickness which helps to capture better light and a higher amount of light while performing photosynthesis. Please refer to and cite https://doi.org/10.1016/j.scienta.2017.12.006 to improve the text accordingly in the introduction section.

 

3) Hypothesis and objectives of the study: Author should rephrase the text in the last paragraph (Ln. 66-72) of the introduction. The hypothesis of the study is an important thing, and it gives another strength to the introduction. The hypothesis should be very clear in the introduction sections because, without appropriate literature, questions, or hypotheses in the introduction section the entire text will be unclear. Please re-phrase this and present the hypothesis and introduction more clearly.

  

  Some other comments

4       Line no. 95 and 104: Author should combine the subsection of the subtitle in the material and method sections. Please see the 2.3 and 2.4 and combine them accordingly. Generally, in scientific writing many subtitles in the MM sections is not recommended.

 

5       Line no. 173-174: Author should be revised the statistical section more clearly. It is hidden what or which traits author did the “correlation analysis” in Ln 174.  Also, the author made incomplete sentences in Ln 176-177 and there is no full stop, please revised this accordingly.

 

6       Line no. 356: The author should carefully present the describe the title of each figure. Please revised the title with different light intensities and some related clear descriptions. Generally, each figure is independent and it should provide the full meaning without referring to the other text or materials.

 

7       Line no. 399-403: The photosynthetic rate and intercellular CO2 concentrations were negatively associated, which indicated that more intense photosynthesis consumed more CO2. The perfect example of pattern of the intercellular CO2 concentrations while performing the Pn is presented Kim et al in this manuscript http://doi.org/10.1016/j.envexpbot.2020.104111. Author should present enough citations and sufficient descriptions.

 

8       Line no. 426-446: In discussion author should frequently refer to the supporting previous result in the discussion section, However, I did not see the supportive references in Ln 436-446. Please mention some references in this section to support your findings.

 

9        Line no. 493 (Conclusion): The conclusion should not be repetitive in the abstract or a summary of the results section. I would love to read take-home messages that will linger in the readers’ minds. What is the novelty, how does the study elucidate some questions in this field, and the contributions the paper may offer to the scientific community?

 

10    Line no. 541 (Reference): please double-check the citations, their style, spell check, and other grammatical errors. moreover, I request to the authors to revise the manuscript according to the journal rules.

 

Good luck !

Author Response

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Round 2

Reviewer 2 Report

The revised manuscript has been greatly improved. However, there are still several issues to be solved.

1. Grammatical mistakes and typos still exist. For example, line 21“than did”. Line 34-35, the tense of the sentence should be present, and “a” should be “an”. Line 282, what is “physioecological”? are you referring to “physiological”? Please check the manuscript thoroughly.

2. The logic of introduction needs to be clearly presented. For example, don’t just lay out the models and the two species of plants; instead, provide why the author chose to study the three models out of so many, why just the two species of plants from so many plants, and why just two growing seasons (early and peak) instead of four seasons?

3. Still, more details are needed for the materials and methods. For example,

4. Line 215, “The data between…” The logic of the sentence is not right.

5. “p” should not be capitalized as in p values.

6. The discussion section is too tedious. Please revise it to be concise. For example, line 453-454 and line 458-459, these two sentences could be merged. Please check the whole section.

 

7. The conclusion is not accurate enough when the second comment has not been well resolved. 

Author Response

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Reviewer 3 Report

1. The title needs to be reconsidered.

2. Language needs to be polished.

3. L69-71, please keep the font format consistent.

4. Significant differences should be marked in figure 2.

 

5. the second conclusion may not suitable. As photosynthetically active radiation is the environmental factor, Stomatal conductivity is the measured parameter.

 

Author Response

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Reviewer 4 Report

Dear Author

I have read the revised review manuscript (forests-1995650). Entitle: Photosynthetic Process and Three Models Fitting of Light Response Curve on Quercus acutissima and Quercus variabilis in the Changjiang River Delta, China for publication of forest MDPI. Author addressed all the questions and suggestions what I raised issue in the review of the original manuscript. I satisfy the author revisions throughout the paper. The abstract issue is well-written by the author. Now, this manuscript improved the flow of writing, which was comparatively shallow in the original version but in this revised copy author address all the quarries and suggestions where the introduction is significantly improved by author. Before accepting this manuscript, I request to author to check the whole manuscript with a native speaker for correct spell check, and other grammatical errors.

 

Author Response

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