Morphophysiological Responses of Black Pepper to GA₃: Growth, Photosynthesis, Carbohydrates and Flowering

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Review Comments

This study addresses the practical challenge of irregular flowering in black pepper by investigating the regulatory effects of GA₃ concentrations on its flowering, photosynthetic physiology, growth and development, as well as carbohydrate metabolism. The research topic aligns with industrial demands and holds considerable theoretical value and practical guiding significance for production. The experimental design is scientific and standardized; the paper is logically structured and formally consistent, with clear conclusions that provide specific concentration references for field practice. However, the paper has room for improvement in terms of the depth of mechanistic analysis, clarity of experimental details, and the correlation between results and discussion, and thus revisions are recommended.

Introduction

1. The review of research progress on flowering regulation in black pepper is superficial, with no detailed elaboration of existing findings, unsolved problems, and research gaps regarding GA₃ application in this field, leading to insufficient pertinence of the research rationale. It is recommended to supplement relevant studies on flowering physiology and phytohormone regulation in black pepper published in the past 5–10 years, so as to clarify the connection and innovation of this study relative to previous research.

Results

1. Some descriptions of the results are repetitive and ambiguous. For example, the inter-cycle differences in indicators are mentioned multiple times, without a hierarchical analysis of the specific patterns of concentration and time effects; for some indicators, only "significant changes" are described without specifying their gradient characteristics. It is recommended to streamline repetitive content and accurately elaborate the specific variation patterns of each indicator.
2. The presentation of figure information is incomplete. For the results of analysis of variance (ANOVA) in Figures 1–9, please add the F-statistic values, which are important parameters for judging the reliability of the results.
3. Figures 10, 12, 13 and 14 can be combined into a single figure with a 2×2 panel layout to save space.

Discussion

1. It is recommended to structure the discussion into three sections following the logical flow of the results: Section 1：Effects on photosynthetic parameters; Section 2：Effects on growth characteristics and biomass allocation; Section 3： Effects on non-structural carbohydrates.
2. The research limitations and future research directions are not mentioned. This study was conducted under pot culture conditions, which differ from field environments; in addition, only two floral induction cycles were observed, resulting in an unclear long-term effect of GA₃. It is recommended to supplement the analysis of research limitations and propose future research directions such as field validation experiments and the synergistic regulatory effects of multiple phytohormones, to make the conclusions more rigorous.

Materials and Methods

1. Details of GA₃ foliar application are lacking, including the number of applications, application interval, and whether a spreading agent was added. It is recommended to supplement these experimental details.
2. Plant physiological parameters are diverse. When investigating the effects of GA₃ on the morphophysiological traits of black pepper, the reasons for selecting the indicators mentioned in the paper (e.g., chlorophyll fluorescence characteristics, chlorophyll content, and carbohydrates) are not explained. It is recommended to add the rationale for indicator selection in this section.
3. The reference list can be supplemented with the latest research (published in the past 3 years) on phytohormone regulation of crop flowering and carbohydrate metabolism, to enhance the research novelty and advancement.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

Hope you are doing well.

In section abstract of the manuscript, "Black pepper (Piper nigrum L.) faces challenges related to irregular flowering, which compromises crop productivity. Gibberellic acid (GA₃) is a plant growth regulator known for its role in inducing reproductive processes, although its effects on this species are not yet fully understood. This study aimed to evaluate the influence of different GA₃ doses on flowering and vegetative growth in black pepper plants." 

But the system of the detected indicators in the experiment design can't answer to the scientific question mentioned above. Additionally, the research does nothing with the molecular mechanism of black pepper flowering.

This study sought to evaluate the effects of GA3 on modulating black pepper flowering.

This study has analyzed GA3’s impact on vegetative development, photochemical efficiency, biomass allocation, and carbohydrate metabolism, but it can’t answer to question 1, so this research does nothing with modulating black pepper flowering directly.

The innovation of this manuscript is very limited because GA3 has been studied in too many crops including modulating black pepper of economic interest, meanwhile only through exploring the changes in few physiological indicators only, and ignoring the yield and quality of modulating black pepper, then it can’t solve the issue on modulating black pepper flowering.

The section conclusions has summarized the key results of this manuscript, but it can’t answer to the question how GA3 regulates modulating black pepper flowering, meanwhile it doesn’t sublimate based on the section discussions, then describes the surface performance only.

If the research object was the effects of GA3 on modulating black pepper flowering, the sections introduce and discussion should focus on the C/N ratio theory according to the indicators system in this manuscript. However it is regrettable that the manuscript can’t sublimate to this high level, so the references aren’t appropriate enough.

The tables and figures of the manuscript are very nice, and the quality of the data is normal.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The study is quite comprehensive and labor-intensive, worthy of publication. However, the presentation and discussion of the data are not without flaws. I believe the text requires revisions that would significantly improve it.

I'll list the main recommendations.
1. Title: Listing chlorophyll and fluorescence separately is strange and unclear. It needs to be reformulated. Chlorophyll fluorescence? (more specifically) Photosynthetic parameters? (more generally)

2. The introduction is too brief. The logic needs to be improved and references added. A justification for the relevance of the study should be added. The effects of gibberellins would be better described following simple logic, for example: (1) first describe their functions in plants, keeping in mind that you are writing here not only and not primarily about flowering, but also cite many other parameters, and the hormone's relationship with them should be outlined in the introduction. Then (2) move on to experiments described in the literature involving spraying various plant species, with a focus on woody species: what were the effects? The choice of study parameters needs to be justified. So far, from the introduction, it seems that studying growth parameters and flowering is all that is needed for practical purposes, since the problem outlined is precisely the transition to flowering.

3. Description of stages. You immediately begin the description of the results with the stages of development, which, as far as I understand, are not described in either the results or the methods. The reader needs to understand right from the start of the results what each stage is and how the hormone affects it.

4. The results indicate huge errors in the number of inflorescences. How can you explain this, and how is statistical significance achieved?
5. The experimental setup with cycles is unclear. I looked in the Methods, and it says this was the only setup used, but cycles are only mentioned in the section on photosynthetic parameters. This should be specified in the Results: how was the procedure performed? Cycles, no cycles? If there were different setups for different parameters, then why? If not, then where are the cycles mentioned in the other sections?

6. Statistics. You show errors in the diagrams that overlap almost everywhere, yet you claim the differences are significant. How is this possible? Why did you use the specific criterion you mentioned? What motivated your choice? The sample is large enough that many criteria could have been applied.

7. Why was the correlation matrix created? (Fig. 9?) It doesn't seem to contain any new information. It's clear that phenotypic traits correlate with each other, leaf size is related to leaf weight, and so on. What's the new information? If this is an auxiliary calculation, perhaps we should simplify the article and move it to the supplementary section?

8. The discussion is very well written and well-written, but I would recommend some additional literature. Some sections literally have only one link, while the carbohydrates discussion includes three articles, all on grapes. Spraying with growth regulators is certainly not uncommon; I'd like to see a comparison with other crops more or less similar to peppers. I'd also be interested in hearing an explanation of the differences between cycles. Is there any such data in the literature?

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Dear authors,

        Thank you for your hard work.

     I feel honoured that my suggestions can help you. Although you have given a major modification and increased the academic level of the manuscript obviously, I think the research level isn't high enough, in particular, the research contents is too much, and yet not complete enough.

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript has been sufficiently improved. I recommend its acceptance for publication.