Physiological, Productive, and Nutritional Performance of Tomato Plants Treated with Iron and Zinc Nanoparticles via Foliar Application Under Deficit Irrigation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

I have reviewed the manuscript entitled “Physiological, productive, and nutritional performance of tomato plants treated with iron and zinc nanoparticles via foliar application under deficit irrigation.” The study addresses a novel and relevant topic by comparing conventional sources with metallic Zn and Fe nanoparticles under field water-deficit conditions. However, I consider that major revisions are required before it can be considered for publication. Below, I detail my comments:

Abstract
The abstract should be improved in accordance with the comments provided for Materials and Methods, Results, and Discussion.

Introduction:

• Line 42: cite references according to the journal’s author guidelines.
• Line 52: reference 9 may confuse the reader; replace it with one related to water deficit.
• Lines 65–66: most of these articles focus on ZnO NPs; include articles on Fe NPs to avoid bias.
• Line 73: reference 20 should be replaced with one specifically addressing drought stress. Although salinity stress shares metabolic pathways with drought stress, there are distinct differences that must be clarified.
• Line 87: I suggest that the final paragraph of the introduction focus solely on either the hypothesis or the objectives, but not both, to avoid redundancy.

Materials and Methods:

• Line 114: cite reference 30 correctly.
• Line 153: indicate the basis for defining NP and sulfate concentrations; if based on a previous study, cite it.
• Lines 162–163: justify why 4.5 g L⁻¹ was applied in the conventional sources and not the equivalent to NPs (200 mg L⁻¹). Clarify whether a single application was made during the trial. Specify the equipment used for foliar application and how drift was avoided to prevent treatment crossover.
• Line 236: correct citation of reference 36 according to the journal’s standards.
• Lines 238–242: verify that the equations match those proposed by Lichtenthaler for pure acetone.
• Line 306: replace “software” with “R language.”

Results:

• Line 322: this paragraph does not interpret electrolyte leakage results; additionally, the graph appears duplicated in Figures 3 and 4.
• Line 325: Ci was significantly affected, with a clear CO₂ reduction at 100% ETc; correct this interpretation.
• Line 338: the interpretation of these results should be integrated with section 3.2.
• Lines 379–380: revise the phrase, since there are no significant differences among treatments:
  “However, under full irrigation, treatment T4 outperformed treatments T1, T2, and T3, but not the control treatment.”
• Lines 396–397: the reported difference does not match Figure 6a. The statement “The 50% ETc irrigation depth reduced boron (B) content by 32.9% in treatment T4, but did not alter the content of this nutrient in the other treatments” should be reviewed.
• Line 441: change A/i to A/Ci; also, the graph of this relationship is not found in Figure 3.

Discussion:

• Line 452: strengthen the discussion by focusing on the comparative effects of NPs and conventional sources under water deficit, particularly highlighting the most relevant results.
• Line 453: in section 4.1 Plant growth, discuss only growth results for greater clarity.
• Line 460: include reference 45.
• Line 462: reference 18 does not address water stress; replace it with an appropriate one.
• Line 464: plant height was not significantly modified; correct this interpretation.
• Line 465: treatments did not significantly alter water use efficiency; clarify this statement.
• Lines 470–471: revise the phrase “but treatments with Fe₂O₃NPs (T2) and ZnONPs (T3) increased A by up to 24.5% under full irrigation” since Figure 3a also shows an increase with conventional sources.
• Line 474: reference 43 does not correspond to nanoparticles but to R; correct it.
• Line 477: cite the reference correctly.
• Line 500: strengthen the discussion with a plausible hypothesis explaining why NPs were more effective than the conventional source in Fe accumulation in fruits.

Conclusions:
Clearly and concisely highlight the main findings, especially the greater Fe translocation to fruits with NPs compared to the conventional source.

The conclusions should emphasize the best results of both Zn and Fe sources under deficit irrigation conditions, without ambiguity.

References:
Ensure that all references are cited in the text and correspond to the content mentioned.
Verify DOI accuracy.
Check formatting according to the journal’s standards, including italics for scientific names.

Sincerely,
Reviewer

Author Response

Response to Reviewer 1

Abstract
The abstract should be improved in accordance with the comments provided for Materials and Methods, Results, and Discussion.

Introduction:

• Line 42: cite references according to the journal’s author guidelines.

Author Response: Thank you, that has been corrected.

• Line 52: reference 9 may confuse the reader; replace it with one related to water deficit.

• Author Response: Thank you. Reference 9 should not have been cited, and it was excluded.

• Lines 65–66: most of these articles focus on ZnO NPs; include articles on Fe NPs to avoid bias.

Author Response; Thank you, that has been corrected.

• Line 73: reference 20 should be replaced with one specifically addressing drought stress. Although salinity stress shares metabolic pathways with drought stress, there are distinct differences that must be clarified.

 

Author Response: Thank you.  Reference  20 has been replaced

• Line 87: I suggest that the final paragraph of the introduction focus solely on either the hypothesis or the objectives, but not both, to avoid redundancy.

Author Response: Thank you.  The hypothesis was removed

Materials and Methods:

• Line 114: cite reference 30 correctly.

Author Response: Thank you, that has been corrected.

• Line 153: indicate the basis for defining NP and sulfate concentrations; if based on a previous study, cite it.

Author Response: The references used as a basis were cited

Lines 162–163: justify why 4.5 g L⁻¹ was applied in the conventional sources and not the equivalent to NPs (200 mg L⁻¹). Clarify whether a single application was made during the trial. Specify the equipment used for foliar application and how drift was avoided to prevent treatment crossover.

Author Response: Justifications and clarifications were included in the text.

• Line 236: correct citation of reference 36 according to the journal’s standards.

• Author Response: Thank you, that has been corrected.

• Lines 238–242: verify that the equations match those proposed by Lichtenthaler for pur acetone.

Author Response: This has been verified

• Line 306: replace “software” with “R language.”

• Author Response: Thank you, that has been corrected.

 

 

 

 

 

Results:

• Line 332: this paragraph does not interpret electrolyte leakage results; additionally, the graph appears duplicated in Figures 3 and 4.

• Author Response: Thank you, that has been corrected.

 

• Line 325: Ci was significantly affected, with a clear CO₂ reduction at 100% ETc; correct this interpretation.

• Author Response: Thank you, that has been corrected.

 

• Line 338: the interpretation of these results should be integrated with section 3.2.

• Author Response: Thank you, that has been corrected.

 

• Lines 379–380: revise the phrase, since there are no significant differences among treatments:
  “However, under full irrigation, treatment T4 outperformed treatments T1, T2, and T3, but not the control treatment.”

Author Response: This sentence refers to the number of fruits per plant (Figure 5b). This was better identified in the text

 

• Lines 396–397: the reported difference does not match Figure 6a. The statement “The 50% ETc irrigation depth reduced boron (B) content by 32.9% in treatment T4, but did not alter the content of this nutrient in the other treatments” should be reviewed.

Author Response: In fact, the sentence was confusing. This has been improved.

• Line 441: change A/i to A/Ci; also, the graph of this relationship is not found in Figure 3.

• Author Response: Thank you, that has been corrected.

 

Discussion:

• Line 452: strengthen the discussion by focusing on the comparative effects of NPs and conventional sources under water deficit, particularly highlighting the most relevant results.
• Linha 452: fortalecer a discussão focando nos efeitos comparativos de PNs e fontes convencionais em situação de déficit hídrico, destacando particularmente os resultados mais relevantes.

 

• Line 453: in section 4.1 Plant growth, discuss only growth results for greater clarity.

• Author Response: Thank you, that has been corrected.

• Line 460: include reference 45.
• Thank you, that has been included.
• Line 462: reference 18 does not address water stress; replace it with an appropriate one.
• Author Response: Thank you. Reference 18 has been replaced.

 

 

 

 

 

• Line 464: plant height was not significantly modified; correct this interpretation.
• Author Response: The text has been substantially improved
• Line 465: treatments did not significantly alter water use efficiency; clarify this statement.

• Author Response: Thank you, that has been modified.

 

• Lines 470–471: revise the phrase “but treatments with Fe₂O₃NPs (T2) and ZnONPs (T3) increased A by up to 24.5% under full irrigation” since Figure 3a also shows an increase with conventional sources.

Author Response: The text has been substantially modified and improved.

• Line 474: reference 43 does not correspond to nanoparticles but to R; correct it.
• Author Response: Thank you. Reference 43 has been replaced.
• Line 477: cite the reference correctly.

• Author Response: Thank you, that has been corrected.

• Line 500: strengthen the discussion with a plausible hypothesis explaining why NPs were more effective than the conventional source in Fe accumulation in fruits.

• Author Response: Thank you, that has been improved.

 

Conclusions:
Clearly and concisely highlight the main findings, especially the greater Fe translocation to fruits with NPs compared to the conventional source.

Author Response: Thank you, that has been improved.

The conclusions should emphasize the best results of both Zn and Fe sources under deficit irrigation conditions, without ambiguity.

Author Response: Thank you, that has been improved.

References:
Ensure that all references are cited in the text and correspond to the content mentioned.
Verify DOI accuracy.
Check formatting according to the journal’s standards, including italics for scientific names.

Author Response: Thank you, that has been verified.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

While several key indicators (such as yield and multiple physiological parameters) showed differences between treatments, some did not reach statistical significance (p > 0.05). This means that the positive conclusions drawn based on these indicators lack sufficient statistical support.

The authors are advised to strictly distinguish between "trend changes" and "significant differences" and avoid overinterpreting data that lacks statistical support.

The introduction is not detailed enough. Check if the abbreviations are correct and if the references are correct. Some sentences are illogical and need to be carefully revised

Author Response

Response to Review 2

1-While several key indicators (such as yield and multiple physiological parameters) showed differences between treatments, some did not reach statistical significance (p > 0.05). This means that the positive conclusions drawn based on these indicators lack sufficient statistical support.

Author Response: The conclusions were modified to a more moderate text in relation to the effects of the treatments as mitigators of the water deficit, considering that the effects were modest in this aspect.

2-The authors are advised to strictly distinguish between "trend changes" and "significant differences" and avoid overinterpreting data that lacks statistical support.

Author Response: Thank you, that has been considerably improved.

 

3- The introduction is not detailed enough. Check if the abbreviations are correct and if the references are correct. Some sentences are illogical and need to be carefully revised

 Response: Introduction  has been considerably improved.

 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This manuscript addresses an important agronomic question and presents a field experiment testing foliar micronutrient (iron and zinc) applications under two irrigation regimes, measuring physiology, yield, and fruit mineral content. The topic is relevant, and the experimental approach is promising, but major revisions are required before the paper is suitable for publication. Key weaknesses include insufficient methodological detail and nanoparticle characterization, inconsistent statistical reporting and missing effect sizes, figures and tables that need reformatting and higher resolution, several factual and typographic errors, overextended mechanistic claims that are not supported by measured data, and an unbalanced citation set with limited coverage of recent work. If the authors (1) add the missing methods and nanoparticle data, (2) present absolute means with uncertainty and full statistical output, (3) correct formatting and caption problems in figures and tables, and (4) tone mechanistic claims to match the data or add confirmatory measurements, the manuscript will be much stronger.

Line-by-line, section-specific comments and required edits

Abstract

L17: Opening sentence is generic. Replace with one clear aim statement, e.g., “We evaluated whether foliar ZnO and Fe₂O₃ nano-oxides and their conventional salts mitigate water deficit effects on tomato (hybrid X) in a split-plot field experiment.”

L18–20: Add experimental design details briefly: irrigation levels, number of foliar treatments, and replicates (for example, “2 irrigation × 5 foliar treatments, 4 replicates”). This allows the reader to evaluate scope immediately.

L21–25: Report main quantitative outcomes, not only percent changes. For example: “Net photosynthesis increased by X µmol m⁻² s⁻¹ (Y%, p = 0.0Z) under T treatment.” If p-values are unavailable, give means ± SE and state significance.

L26–29: Avoid contradictory statements. If ZnSO₄ produced the largest yield but nanoparticles increased some physiological traits, say so explicitly (e.g., “Nanoparticles improved physiological metrics but conventional ZnSO₄ produced the largest yield gains”).

L30–33: Add a concise concluding sentence about applicability and main recommendation, and mention limitations (single season, single cultivar) in one short clause.

Introduction

L37–42: Tighten background. Add a single sentence with justification for the field site or crop choice (e.g., regional relevance, climate).

L43–52: When introducing nanoparticles, define the specific rationale for using ZnO and Fe₂O₃ rather than other formulations. Cite a recent review to back up claims about foliar NP uptake.

L53–63: The phrase “nano-enzyme activators” is imprecise. Replace with specific mechanisms reported in the literature (e.g., enhanced micronutrient bioavailability, modified antioxidant enzyme activity) and cite studies that measured these endpoints.

L64–75: Explicitly state the knowledge gap your study addresses. For example: “Field evidence comparing foliar nano-oxides to conventional salts under deficit irrigation is scarce; this study addresses that gap.”

L76–83: End the introduction with a clear hypothesis and objectives. For example: “We hypothesize that foliar ZnO and Fe₂O₃ NPs better maintain photosynthesis and yield under deficit irrigation. Objectives: (i) compare NPs vs salts, (ii) quantify effects on physiology and fruit minerals, and (iii) test interactions with irrigation.”

Materials and Methods

L97–110 (Site, design):

• Provide decimal coordinates, a one-line climate summary (mean annual rainfall, mean temperatures), and the experiment year(s).
• Describe the plot layout (plot size, border rows), randomization, and split-plot implementation (which factor was the main plot).

L111–150 (Treatments & application):

• For each foliar treatment, give the exact concentration (g L⁻¹ or mg L⁻¹), application dates (days after transplanting), number of sprays, spray volume per plant or L ha⁻¹, adjuvant or surfactant used, nozzle type, and pressure. State whether applications were in the morning or evening.
• Explain how nanoparticle suspensions were prepared (solvent, sonication time, dispersant), and whether stability/aggregation was checked.

L151–200 (Nanoparticle characterization):

• Add supplier, batch number, purity, primary particle size (TEM/SEM), hydrodynamic diameter (DLS), zeta potential, and specific surface area if available. If you do not have these data, measure at least TEM images and DLS and include them as supplementary.
• Describe storage conditions and shelf life of suspensions.

L201–240 (Crop management & measurements):

• Give fertilizer rates in kg ha⁻¹, irrigation scheduling details (how 50% ETc and 100% ETc were calculated), and how ETc was estimated (sensor, Penman-Monteith, crop coefficient).
• For gas exchange and pigment measurements, include instrument make/model, leaf position, time of day, and environmental conditions (PAR, ambient CO₂, and temperature).
• For yield and fruit analyses, state plants per plot, fruits sampled per plot, sampling method, drying protocol, and lab instrument for mineral analysis (ICP-OES or ICP-MS, model).

L241–306 (Statistical analysis):

• State software with version (R 4.x; package names), ANOVA model (split-plot: random/main plot terms), degrees of freedom, F-tests for main effects and interactions, post-hoc test used, and assumption checks (Shapiro-Wilk, Levene). Provide effect size metrics and report means ± SE with sample size n. If mixed models are used, show the model formula and random effects.

Results

General: All reported percent changes must be accompanied by absolute means ± SE and p-values. Add tables that list means, SE, and post-hoc group letters for each measured variable.

L307–330 (Growth and morphology):

• For each growth variable report the control mean, treatment means, SE, and statistical letters. State n and exact p-values. Avoid claiming significance without numbers.

L331–360 (Gas exchange and pigments):

• Present A, gs, E, Ci, and chlorophyll data in one table for clarity. Indicate whether increases in A were accompanied by gs changes and discuss implications for intrinsic water use efficiency (A/gs). If WUE was calculated, present it.

L361–390 (Yield and fruit traits):

• For yields, give marketable and total yield per plot (kg plot⁻¹ or t ha⁻¹) with SE and p-values. Provide fruit number and average fruit weight separately. If ZnSO₄ increased yield by 61% (as earlier claimed), show raw numbers (e.g., control 12 t ha⁻¹ vs. 19 t ha⁻¹).

L391–425 (Mineral content):

• Report Fe and Zn concentrations in fruit (mg kg⁻¹) with SE and discuss nutritional relevance relative to dietary reference intakes. If NPs increased fruit Fe by 117%, show baseline and final concentrations and comment on potential human nutrition benefits or safety.

L426–451 (Correlations and multivariate):

• Provide a full correlation matrix as supplementary material and state the correction method for multiple testing. For any PCA or multivariate ordination, include explained variance per axis and loading values for key variables.

Discussion

L452–470: Start by summarizing the most important findings with numbers, then interpret them. Avoid repeating tables or figures.

L471–490: For physiological effects, discuss mechanisms supported by either your data or literature (for example, improvements in A might result from improved chloroplast function, but only claim this if you measured related metrics; otherwise, propose it as a hypothesis and cite supporting studies).

L491–505: Discuss why ZnSO₄ gave large yield increases while NPs improved some physiological parameters. Consider explanations such as leaf retention, mobility, timing of supply, or antagonisms. Reconcile conflicting results.

L506–520: Add a paragraph on the safety and environmental fate of foliar NPs: potential for drift, runoff, accumulation in soil, and required ecotoxicity testing. This is essential if recommending NP use.

Conclusions (Lines 521–530)

L521–525: Make succinct take-home statements grounded in the data, e.g., “Under our conditions, foliar ZnSO₄ increased total yield most strongly, while Fe₂O₃ NPs increased fruit Fe concentration under deficit; growers should select treatment based on production goal (yield vs biofortification).”

L526–530: Explicitly list limitations (single season, single cultivar, limited NP fate data) and concrete next steps (multi-season trials, NP fate and TEM imaging, dose–response work).

References and figures

Ensure all references follow the journal’s bibliographic style (author initials, year, article title, journal name italicized, volume, page range, DOI). Check in-text citation numbering order. Add more recent and mechanistic studies on foliar nanoparticle uptake and effects, and include references on NP characterization and environmental fate. Remove or update any outdated citations if better alternatives exist. Verify every in-text citation appears in the reference list and vice versa.

Reformat all figures as high-resolution images (≥ 300 dpi), correct captions, and place captions below figures. Explain significance letters and sample size in each legend.

Author Response

Response to Review 3

This manuscript addresses an important agronomic question and presents a field experiment testing foliar micronutrient (iron and zinc) applications under two irrigation regimes, measuring physiology, yield, and fruit mineral content. The topic is relevant, and the experimental approach is promising, but major revisions are required before the paper is suitable for publication.

Key weaknesses include insufficient methodological detail and nanoparticle characterization, inconsistent statistical reporting and missing effect sizes, figures and tables that need reformatting and higher resolution, several factual and typographic errors, overextended mechanistic claims that are not supported by measured data, and an unbalanced citation set with limited coverage of recent work. If the authors (1) add the missing methods and nanoparticle data, (2) present absolute means with uncertainty and full statistical output, (3) correct formatting and caption problems in figures and tables, and (4) tone mechanistic claims to match the data or add confirmatory measurements, the manuscript will be much stronger.

Author Response:

• The materials and methods section has been substantially improved. Nanoparticles used in this work were purchased directly from MERK Life Science Research, imported from Germany. The text of the materials and methods section provides some physical properties of these materials, such as purity, specific surface area, and size range. Unfortunately, we currently do not have electron micrographs or X-ray diffractograms.

 

• A table with analysis of variance with all data and their respective means was provided as Supplentary material

 

• Formatting and caption problems in figures and tables, have been corrected.

 

Abstract

L17: Opening sentence is generic. Replace with one clear aim statement, e.g., “We evaluated whether foliar ZnO and Fe₂O₃ nano-oxides and their conventional salts mitigate water deficit effects on tomato (hybrid X) in a split-plot field experiment.”

Author Response: Thank you.  The Abstract has been considerably improved.

L18–20: Add experimental design details briefly: irrigation levels, number of foliar treatments, and replicates (for example, “2 irrigation × 5 foliar treatments, 4 replicates”). This allows the reader to evaluate scope immediately.

Author Response: Thank you. This detail has been added.

L21–25: Report main quantitative outcomes, not only percent changes. For example: “Net photosynthesis increased by X µmol m−2 s−1 (Y%, p = 0.0Z) under T treatment.” If p-values are unavailable, give means ± SE and state significance.

Author Response: Thank you for the suggestion. We avoided including absolute values ​​in the text to avoid duplication of information. To address this gap, we provide as Supplementary material a table with all the means for all the variables evaluated, including their respective standard error (± SE) values.

L26–29: Avoid contradictory statements. If ZnSO₄ produced the largest yield but nanoparticles increased some physiological traits, say so explicitly (e.g., “Nanoparticles improved physiological metrics but conventional ZnSO₄ produced the largest yield gains”).

Author Response: Thank you.  With the abstract improvements, this has been also corrected

L30–33: Add a concise concluding sentence about applicability and main recommendation, and mention limitations (single season, single cultivar) in one short clause.

Author Response: Thank you.  with the abstract improvements, this has been  corrected

 

Introduction

L37–42: Tighten background. Add a single sentence with justification for the field site or crop choice (e.g., regional relevance, climate).

Author Response: Thank you. This  sentence has been added.

L43–52: When introducing nanoparticles, define the specific rationale for using ZnO and Fe₂O₃ rather than other formulations. Cite a recent review to back up claims about foliar NP uptake.

Author Response: Thank you. This  sentence has been added.

L53–63: The phrase “nano-enzyme activators” is imprecise. Replace with specific mechanisms reported in the literature (e.g., enhanced micronutrient bioavailability, modified antioxidant enzyme activity) and cite studies that measured these endpoints.

Author Response: This  phrase has been improved.

L64–75: Explicitly state the knowledge gap your study addresses. For example: “Field evidence comparing foliar nano-oxides to conventional salts under deficit irrigation is scarce; this study addresses that gap.”

Author Response: A sentence has been added to justify our study.

L76–83: End the introduction with a clear hypothesis and objectives. For example: “We hypothesize that foliar ZnO and Fe₂O₃ NPs better maintain photosynthesis and yield under deficit irrigation. Objectives: (i) compare NPs vs salts, (ii) quantify effects on physiology and fruit minerals, and (iii) test interactions with irrigation.”

Author Response: Thank you. The final Phrase has been modified.

Materials and Methods

L97–110 (Site, design):

Provide decimal coordinates, a one-line climate summary (mean annual rainfall, mean temperatures), and the experiment year(s).

 Author Response: Thank you. This data has been added.

Describe the plot layout (plot size, border rows), randomization, and split-plot implementation (which factor was the main plot).

Author Response: For a better understanding of the experimental design, corrections were made to the text regarding this information and a sketch of the experimental area was inserted as an Appendix.

L111–150 (Treatments & application):

For each foliar treatment, give the exact concentration (g L⁻¹ or mg L⁻¹), application dates (days after transplanting), number of sprays, spray volume per plant or L ha⁻¹, adjuvant or surfactant used, nozzle type, and pressure. State whether applications were in the morning or evening.

Author Response: Thank you. All these information has been provided.

Explain how nanoparticle suspensions were prepared (solvent, sonication time, dispersant), and whether stability/aggregation was checked.

Author Response: Additional information on the preparation of nanoparticle suspensions has been added to the text. However Solvent, sonication time, dispersant, and stability/aggregation could not measure.

L151–200 (Nanoparticle characterization):

Add supplier, batch number, purity, primary particle size (TEM/SEM), hydrodynamic diameter (DLS), zeta potential, and specific surface area if available. If you do not have these data, measure at least TEM images and DLS and include them as supplementary. Describe storage conditions and shelf life of suspensions.

Author Response: Thank you very much for these observations. Several additional pieces of information on nanoparticle characterization have been included in the text. Unfortunately, it was not possible to produce more in-depth characterizations such as X-ray diffractograms or scanning electron micrographs, as the products used are no longer available.

L201–240 (Crop management & measurements):

Give fertilizer rates in kg ha⁻¹, irrigation scheduling details (how 50% ETc and 100% ETc were calculated), and how ETc was estimated (sensor, Penman-Monteith, crop coefficient).

Author Response: All these information has been provided.

For gas exchange and pigment measurements, include instrument make/model, leaf position, time of day, and environmental conditions (PAR, ambient CO₂, and temperature).

Author Response: This information has been inserted into the text.

For yield and fruit analyses, state plants per plot, fruits sampled per plot, sampling method, drying protocol, and lab instrument for mineral analysis (ICP-OES or ICP-MS, model).

Author Response: All these information has been provided.

L241–306 (Statistical analysis):

State software with version (R 4.x; package names), ANOVA model (split-plot: random/main plot terms), degrees of freedom, F-tests for main effects and interactions, post-hoc test used, and assumption checks (Shapiro-Wilk, Levene). Provide effect size metrics and report means ± SE with sample size n. If mixed models are used, show the model formula and random effects.

Author Response: State software with version has been provided. For better understanding of the statistical procedures/methods, an analysis of variance (ANOVA) table was provided as Appendix.

Results

General: All reported percent changes must be accompanied by absolute means ± SE and p-values. Add tables that list means, SE, and post-hoc group letters for each measured variable.

Author Response: Some of this information has been added to the text. Other data has been provided in table form (Appendix ) to avoid texts that are overly cluttered with information.

L307–330 (Growth and morphology):

2-For each growth variable report the control mean, treatment means, SE, and statistical letters. State n and exact p-values. Avoid claiming significance without numbers.

L331–360 (Gas exchange and pigments):

3-Present A, gs, E, Ci, and chlorophyll data in one table for clarity. Indicate whether increases in A were accompanied by gs changes and discuss implications for intrinsic water use efficiency (A/gs). If WUE was calculated, present it.

Author Response: Positive correlation between A and Gs was demonstrated by the correlation analysis shown in Figure 8.

L361–390 (Yield and fruit traits):

4-For yields, give marketable and total yield per plot (kg plot−1 or t ha−1) with SE and p-values. Provide fruit number and average fruit weight separately. If ZnSO₄ increased yield by 61% (as earlier claimed), show raw numbers (e.g., control 12 t ha⁻¹ vs. 19 t ha⁻¹).

Author Response: Some of this information has been added to the text. Other data has been provided in table form (Appendix ) to avoid texts that are overly cluttered with information.

L391–425 (Mineral content):

5- Report Fe and Zn concentrations in fruit (mg kg⁻¹) with SE and discuss nutritional relevance relative to dietary reference intakes. If NPs increased fruit Fe by 117%, show baseline and final concentrations and comment on potential human nutrition benefits or safety.

Author Response: All these information has been provided.

L426–451 (Correlations and multivariate):

6- Provide a full correlation matrix as supplementary material and state the correction method for multiple testing. For any PCA or multivariate ordination, include explained variance per axis and loading values for key variables.

Author Response: Figures with these analyses were provided as supplementary material.

Discussion

7- L452–470: Start by summarizing the most important findings with numbers, then interpret them. Avoid repeating tables or figures.

Author Response: Thank you. Discussion  has been considerably improved.

8- L471–490: For physiological effects, discuss mechanisms supported by either your data or literature (for example, improvements in A might result from improved chloroplast function, but only claim this if you measured related metrics; otherwise, propose it as a hypothesis and cite supporting studies).

Author Response: This topic has been substantially improved.

1- L491–505: Discuss why ZnSO₄ gave large yield increases while NPs improved some physiological parameters. Consider explanations such as leaf retention, mobility, timing of supply, or antagonisms. Reconcile conflicting results.

Author Response: The discussion of this topic has been substantially improved.

2- L506–520: Add a paragraph on the safety and environmental fate of foliar NPs: potential for drift, runoff, accumulation in soil, and required ecotoxicity testing. This is essential if recommending NP use.

Author Response: A sentence on this topic has been included

Conclusions (Lines 521–530)

3-L521–525: Make succinct take-home statements grounded in the data, e.g., “Under our conditions, foliar ZnSO₄ increased total yield most strongly, while Fe₂O₃ NPs increased fruit Fe concentration under deficit; growers should select treatment based on production goal (yield vs biofortification).”

Author Response: This topic has been substantially improved.

4- L526–530: Explicitly list limitations (single season, single cultivar, limited NP fate data) and concrete next steps (multi-season trials, NP fate and TEM imaging, dose–response work).

Author Response: A sentence on this topic has been included

 

 

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The research investigated the physiological, productive, and nutritional performance of tomato plants treated with iron and zinc nanoparticles via foliar application under deficit irrigation, studies on this aspect help to mitigate the drought stress and improve the yield of crops subjected to water deficit conditions, which is of great significance for the cultivation of horticultural crops. However, the current manuscript still has some drawbacks need to be addressed before it can be considered for publication.

1, At the end of the Introduction, the author should clearly point out the research gap between the study presented in this paper and previous studies, as well as where its innovations lie.

2, In the "Materials and Methods" section, the method for foliar application of iron and zinc sources should be described in detail, including the specific application sites, timing, frequency, dosage.

3, In both the 50% Etc and 100% Etc treatments shown in the Figure 2, there is a blank control, and both are labeled "C". If the treatments for these two blank controls are not completely consistent, it is recommended to use different letters for labeling to distinguish them. All labels in the subsequent figures should be revised correspondingly.

4, In the 4.2 section, the positive effects of foliar application of iron (Fe) and zinc (Zn) on A and Gs under different water treatments, as well as the variations in the impacts of different Fe and Zn forms on A and Gs, require detailed explanations of their underlying mechanisms.

5, Different forms of Fe and Zn also exhibit varying effects on promoting the accumulation of Fe and Zn in fruits, yet the Discussion section lacks corresponding explanations for this phenomenon.

Author Response

Response to Review 4

The research investigated the physiological, productive, and nutritional performance of tomato plants treated with iron and zinc nanoparticles via foliar application under deficit irrigation, studies on this aspect help to mitigate the drought stress and improve the yield of crops subjected to water deficit conditions, which is of great significance for the cultivation of horticultural crops. However, the current manuscript still has some drawbacks need to be addressed before it can be considered for publication.

1, At the end of the Introduction, the author should clearly point out the research gap between the study presented in this paper and previous studies, as well as where its innovations lie.

Author Response: Thank you. This information has been added.

2, In the "Materials and Methods" section, the method for foliar application of iron and zinc sources should be described in detail, including the specific application sites, timing, frequency, dosage.

Author Response: All this information was added to the text of the material and methods item

3, In both the 50% Etc and 100% Etc treatments shown in the Figure 2, there is a blank control, and both are labeled "C". If the treatments for these two blank controls are not completely consistent, it is recommended to use different letters for labeling to distinguish them. All labels in the subsequent figures should be revised correspondingly.

Author Response:: We appreciate the reviewer's concern. The study employed a spatial split-plot design, meaning that treatments C, T1, T2, T3, and T4 were replicated (of identical composition)  across two separate irrigation levels.

4, In the 4.2 section, the positive effects of foliar application of iron (Fe) and zinc (Zn) on A and Gs under different water treatments, as well as the variations in the impacts of different Fe and Zn forms on A and Gs, require detailed explanations of their underlying mechanisms.

Author Response: In this regard, the text has been improved.

5, Different forms of Fe and Zn also exhibit varying effects on promoting the accumulation of Fe and Zn in fruits, yet the Discussion section lacks corresponding explanations for this phenomenon.

Author Response: This discussion began with Zn sources, (“Performance differences between NPs may stem from physical properties: Fe₂O₃ NPs (<50 nm; 50–245 m² g⁻¹ surface area) vs. ZnO NPs (<100 nm; 10.8 m² g⁻¹”)  but was expanded to include Fe sources and ZnO NPs vs ZnSO₄7H₂O sources.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have addressed the review comments. Therefore, the manuscript can be accepted for publication.

Reviewer 3 Report

Comments and Suggestions for Authors

Thank you for your thoughtful revisions and responses to the comments provided in the first round of review. I am pleased to see that you have addressed the suggestions effectively and improved the clarity and quality of the manuscript. Having reviewed the revised version, I believe that the manuscript is now suitable for publication in its current form. I have no further comments or suggestions.

Congratulations on your work, and I look forward to seeing the published article.

Reviewer 4 Report

Comments and Suggestions for Authors

The authors have addressed all my concerns, and thanks for their hard work on the improvement of this manuscript, I have no other questions.