Seaweed Extract Improves Growth and Productivity of Tomato Plants under Salinity Stress
, Carla Vanessa Sánchez-Hernández 2, Paola Andrea Palmeros-Suárez 2, Héctor Ocampo-Alvarez 3, Fernando Santacruz-Ruvalcaba 2, Iván David Meza-Canales 1 and Amayaly Becerril-Espinosa 3,4
Round 1
Reviewer 1 Report
agronomy-1940170
The aim of the present work is to investigate the effect of seaweed treatments on tomato plants, under salinity stress condition.
In my opinion the manuscript is interesting and timely, since regards the use of biostimulants that could promote crops growth and productivity, as well as resistance to abiotic stress, reducing at the same time the application of chemical products. However, I think that the manuscript should be improved in some aspects to be more complete and suitable for the journal.
Please find more comments in detail:
ABSTRACT: I recommend reviewing the abstract, which in its current form seems to me too generic and lacks important information related to the experiment carried out. The methods are missing, nothing is reported on the treatments performed.
KEY WORDS: I suggest adding Solanum lycopersicum L.
INTRODUCTION:
Line 60: write the scientific name of the tomato comprehensively.
Line 81: delete the word “crop”.
Lines 98-99: the concept is well known; I think it can be eliminated.
M&M:
Line 132: I suggest including in the manuscript the composition of the extract used, which can also help the reader to better understand its effects. It could be included in the supplementary mat.
Figure 1: inside the figure, I suggest to modify the sentence “In a first phase” with “In the first phase.
Lines 235-240 etc: check the units of measurement that express the temperature and standardize them in style.
Line 256: the city is missing.
Line 299: correct the reference.
RESULTS:
Table 2: in all tables, replace “between” with “among” in the caption.
Line 386: replace “those of the plants not treated with the SE” with “untreated plants”.
Table 3: at the end of the caption, I suggest adding the sentence “and reported as percentage”.
Table 4: the caption is not very clear to the reader.
Lines 421-422: FV/FM is always below the threshold value of 0.83; how do the authors explain this? Plants seem to be in a condition of stress.
Table 5: among the chlorophyll a fluorescence indices, has the PI not been measured? It could give a further data related to plants health status. I also suggest to sort the indexes within the table in the sequence in which they are described in the text.
Figure 4: please add a, b, c to the three figures.
DISCUSSION:
Line 576: I find the verb “mitigate” more suitable than “overcome”.
Lines 644-647: I suggest revising this part based on the comments written above (Fv/FM).
Lines 711-713: is it possible that the extract contains proline?
CONCLUSIONS:
Lines: 768-771: this sentence does not seem relevant to me, even considering that in the current version of the manuscript there is no composition of the biostimulant used. I suggest changing the sentence with content related to the work.
I invite the authors to carefully re-read the text and to make the required corrections.
Author Response
The authors are grateful and appreciate the valuable comments of the reviewer. Below is a point-by-point response to the Reviewer’s comments, which expands in detail on the points they raised and describes the revision that we have made to the manuscript. We are grateful for the valuable comments and hope that we have satisfactorily interpreted and addressed all concerns. We believe that we now have a significantly improved version of the manuscript for your consideration and hope that the revised manuscript will be suitable for publication in Agronomy. To facilitate the process of assessing our responses, our answers appear in bold.
Changes made to the document are highlighted in yellow for Reviewer 1 and blue for Reviewer 2.
Review 1. Comments and Suggestions for Authors
The manuscript is well-written and the topic is relevant and interesting. Nevertheless, it requires some changes:
Keywords: I suggest to replace "antioxidant enzyme" and "metabolite" with "antioxidant enzyme activity" and "primary and secondary metabolites", respectively. Line 42. Done.
Introduction:
- line 60: Solanum lycopersicum L., please add L. Line 62. Done.
Material and Methods:
1- why physiological parameters was not evaluated in the second phase?
The physiological parameters were measured in the second phase of the experiment, but there were no significant differences between treatments; therefore, they were not included in the study.
2- the order of the paragraphs should be following the order of which results are presented. I suggest to report firstly the results obtained in the vegetative stage and then the ones obtained in the reproductive stage. Therefore:
- no changes from 2.1 to 2.4; - plant growth measurement - physiological parameters (photosynthetic performance should precede chlorophyll measurements) -no changes from 2.7 to 2.9. Following the recommendations of the reviewer, the suggestions were addressed, and the information in the Results is presented following the same order of the Methods.
3- why ΦPSII was not evaluated as photosynthetic performance? If available, please add this parameter.
We used ΦPSII because we caculated ETR at different light intensities and constructed a light curve to obtain ETRMAX. The addition of ΦPSII at a specific light intensity could be redundant since the correlation with the measured ETR would be 100%.
4- I always suggest to include a second antioxidant assay to confirm the results obtained with DPPH radical scavenging assay. If possible, I recommend to perform ABTS or FRAP assays.
5- Please explain why authors chosen to evaluate only SOD and CAT as antioxidant enzymes involved in ROS detoxification, excluding APX.
The ABTS and APX assays requested by the reviewer in points 4 and 5 were previously conducted and analyzed. This information was not initially incorporated into the study because they were very similar, and we only thought of showing one of the two results. However, at the request of the reviewer, the information has been incorporated into Table 5 and Figure 3c.
6- line 309: please add a reference relatively to Mohr method (Line 346. The reference is included).
7-line 311: "and fruits" is repeated twice (Line 349. This was modified)
Results
1- I suggest to report firstly the results obtained in the vegetative stage and then the ones obtained in the reproductive stage also in this section. Following the recommendations of the reviewer, the suggestions were addressed, and the information in the Results is presented following the same order of the Methods.
2- please use a letter for the highest values
This point was not addressed because we did not understand where this change should be made.
3- line 361: replace 0.00.1 with 0.001 Done.
4- line 422, 424, 4,26, 427, 428: replace FV/FM with FV/FM. Done.
5- table 5: "control" should not be in bold and the size of the table footer is incorrect. The order of the parameters should follow the order in which they are mentioned in the text, and hence: ETR, FV/FM, NPQ, chlorophyll. Done in table 2.
Why light saturation index (Ek) (reported in materials and methods, line 211) was not included in Table 5? The information was incorporated in table 2.
6- line 467-468. Please revise this sentence according to Figure 4. Done.
7- line 484, 488. Remove italic from "salinity stress" Done.
8- line 492: TRS could be a more suitable acronym for total reducing sugars instead of RTS. Done.
9- line 506: why authors did not measured carotenoids if they described them as "among the most relevant antioxidant metabolites known to respond to salinity stress"?
The carotenoids were measured. It was an oversight on our part that the table was sent without the information. Information is now included.
10- line 507: the meaning of REF acronym is unclear. Done.
11- Table 6: "proline" should not be in bold and the size of the table footer is incorrect. Done.
12- line 568. A reference is required at the end of the sentence. Done.
Discussion
1- line 686: replace seaweed extract with SE. Done.
2- the text should be revised according to the changes in the previous sections. Done.
Lastly, I suggest to the Authors to perform a chemical characterization of their SE, that could be published in a further work. The chemical characterization of the seaweed powder and the extract has already been conducted. The information is shown in Supplementary Tables 1 and 2.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The manuscript is well-written and the topic is relevant and interesting. Nevertheless, it requires some changes:
Keywords: I suggest to replace "antioxidant enzyme" and "metabolite" with "antioxidant enzyme activity" and "primary and secondary metabolites", respectively.
Introduction:
- line 60: Solanum lycopersicum L., please add L.
Material and Methods:
1- why physiological parameters was not evaluated in the second phase?
2- the order of the paragraphs should be follow the order of which results are presented. I suggest to report firstly the results obtained in the vegetative stage and then the ones obtained in the reproductive stage. Therefore:
- no changes from 2.1 to 2.4;
- plant growth measurement
- physiological parameters (photosynthetic performance should precede chlorophyll measurements)
-no changes from 2.7 to 2.9
3- why ΦPSII was not evaluated as photosynthetic performance? If available, please add this parameter.
4- I always suggest to include a second antioxidant assay to confirm the results obtained with DPPH radical scavenging assay. If possible, I recommend to perform ABTS or FRAP assays.
5- Please explain why authors chosen to evaluate only SOD and CAT as antioxidant enzymes involved in ROS detoxification, excluding APX.
6- line 309: please add a reference relatively to Mohr method
7-line 311: "and fruits" is repeated twice
Results
1- I suggest to report firstly the results obtained in the vegetative stage and then the ones obtained in the reproductive stage also in this section
2- please use a letter for the highest values
3- line 361: replace 0.00.1 with 0.001
4- line 422, 424, 4,26, 427, 428: replace FV/FM with FV/FM
5- table 5: "control" should not be in bold and the size of the table footer is incorrect. The order of the parameters should follow the order in which they are mentioned in the text, and hence: ETR, FV/FM, NPQ, chlorophyll. Why light saturation index (Ek) (reported in materials and methods, line 211) was not included in Table 5?
6- line 467-468. Please revise this sentence according to Figure 4
7- line 484, 488. Remove italic from "salinity stress"
8- line 492: TRS could be a more suitable acronym for total reducing sugars instead of RTS
9- line 506: why authors did not measured carotenoids if they described them as "among the most relevant antioxidant metabolites known to respond to salinity stress"?
10- line 507: the meaning of REF acronym is unclear
11- Table 6: "proline" should not be in bold and the size of the table footer is incorrect.
12- line 568. A reference is required at the end of the sentence
Discussion
1- line 686: replace seaweed extract with SE
2- the text should be revised according to the changes in the previous sections.
Lastly, I suggest to the Authors to perform a chemical characterization of their SE, that could be published in a further work.
Author Response
The authors are grateful and appreciate the valuable comments of the reviewer. Below is a point-by-point response to the Reviewer’s comments, which expands in detail on the points they raised and describes the revision that we have made to the manuscript. We are grateful for the valuable comments and hope that we have satisfactorily interpreted and addressed all concerns. We believe that we now have a significantly improved version of the manuscript for your consideration and hope that the revised manuscript will be suitable for publication in Agronomy. Changes made to the document are highlighted in yellow for Reviewer 2 and blue for Reviewer 3.
Review 1. Comments and Suggestions for Authors
The manuscript is well-written and the topic is relevant and interesting. Nevertheless, it requires some changes:
Keywords: I suggest to replace "antioxidant enzyme" and "metabolite" with "antioxidant enzyme activity" and "primary and secondary metabolites", respectively. Line 42. Done.
Introduction:
- line 60: Solanum lycopersicum L., please add L. Line 62. Done.
Material and Methods:
1- why physiological parameters was not evaluated in the second phase?
The physiological parameters were measured in the second phase of the experiment, but there were no significant differences between treatments; therefore, they were not included in the study.
2- the order of the paragraphs should be following the order of which results are presented. I suggest to report firstly the results obtained in the vegetative stage and then the ones obtained in the reproductive stage. Therefore:
- no changes from 2.1 to 2.4; - plant growth measurement - physiological parameters (photosynthetic performance should precede chlorophyll measurements) -no changes from 2.7 to 2.9. Following the recommendations of the reviewer, the suggestions were addressed, and the information in the Results is presented following the same order of the Methods.
3- why ΦPSII was not evaluated as photosynthetic performance? If available, please add this parameter.
We used ΦPSII because we caculated ETR at different light intensities and constructed a light curve to obtain ETRMAX. The addition of ΦPSII at a specific light intensity could be redundant since the correlation with the measured ETR would be 100%.
4- I always suggest to include a second antioxidant assay to confirm the results obtained with DPPH radical scavenging assay. If possible, I recommend to perform ABTS or FRAP assays.
5- Please explain why authors chosen to evaluate only SOD and CAT as antioxidant enzymes involved in ROS detoxification, excluding APX.
The ABTS and APX assays requested by the reviewer in points 4 and 5 were previously conducted and analyzed. This information was not initially incorporated into the study because they were very similar, and we only thought of showing one of the two results. However, at the request of the reviewer, the information has been incorporated into Table 5 and Figure 3c.
6- line 309: please add a reference relatively to Mohr method (Line 346. The reference is included).
7-line 311: "and fruits" is repeated twice (Line 349. This was modified)
Results
1- I suggest to report firstly the results obtained in the vegetative stage and then the ones obtained in the reproductive stage also in this section. Following the recommendations of the reviewer, the suggestions were addressed, and the information in the Results is presented following the same order of the Methods.
2- please use a letter for the highest values
This point was not addressed because we did not understand where this change should be made.
3- line 361: replace 0.00.1 with 0.001 Done.
4- line 422, 424, 4,26, 427, 428: replace FV/FM with FV/FM. Done.
5- table 5: "control" should not be in bold and the size of the table footer is incorrect. The order of the parameters should follow the order in which they are mentioned in the text, and hence: ETR, FV/FM, NPQ, chlorophyll. Done in table 2.
Why light saturation index (Ek) (reported in materials and methods, line 211) was not included in Table 5? The information was incorporated in table 2.
6- line 467-468. Please revise this sentence according to Figure 4. Done.
7- line 484, 488. Remove italic from "salinity stress" Done.
8- line 492: TRS could be a more suitable acronym for total reducing sugars instead of RTS. Done.
9- line 506: why authors did not measured carotenoids if they described them as "among the most relevant antioxidant metabolites known to respond to salinity stress"?
The carotenoids were measured. It was an oversight on our part that the table was sent without the information. Information is now included.
10- line 507: the meaning of REF acronym is unclear. Done.
11- Table 6: "proline" should not be in bold and the size of the table footer is incorrect. Done.
12- line 568. A reference is required at the end of the sentence. Done.
Discussion
1- line 686: replace seaweed extract with SE. Done.
2- the text should be revised according to the changes in the previous sections. Done.
Lastly, I suggest to the Authors to perform a chemical characterization of their SE, that could be published in a further work. The chemical characterization of the seaweed powder and the extract has already been conducted. The information is shown in Supplementary Tables 1 and 2.
Author Response File: Author Response.docx
Reviewer 3 Report
The manuscript deals with the role of seaweed extract on the physiology and biochemistry of tomato plants grown under salinity stress. Soil salinity is a problem in many areas, therefore, studies with agents which could alleviate salinity stress and improve plant health conditions are needed. The Authors should replace old references with newer ones. The comments are listed below:
L29-30: add number or % values for these parameters
L76-80: start at the new paragraph and add at the beginning one or two introductory sentences related to antioxidant enzymes and non-enzymatic antioxidants in mitigation of various abiotic stresses (e.g. this reference: https://doi.org/10.1016/j.scienta.2022.110988)
L174: 46 DAG – in the Fig. 1 the second phase starts in 48 DAG
L176-178: according to the Fig. 1, fertilization was also carried out in 23 DAG – add to the text
L191: indicate how many repetitions for each analyzed parameter were performed?
L361: p ≤ 0.001
L368: add values of examined parameters for different treatments in this paragraph
L387-388: number instead proportion
L437-444: add values of these parameters
L484-498: add values of these parameters
L484 and L488: salinity stress without italics
L498-502: these statements are suitable for Discussion
L507-509: rephrase this sentence to passive voice
L549: attraction
L556: mine nutrients – rephrase
L609: A. nodosum in full name when it appears for the first time in the text
L669: reduced acquisition – according to the Fig. 4 it is enhanced acquisition
L673: Na+
L675: Bougainvillea in italics
L691: ‘which have antioxidant properties’ instead ‘which are a source of antioxidant compounds’
L718-752: shorten these two paragraphs and compare the results from described publications with CAT and SOD activity determined in this study
L765: according to the Fig. 4, reduction of Na+ and K+
For Table 3, 4, 5 and 6, add the text below these tables to the footnote.
Author Response
The authors are grateful and appreciate the valuable comments of the reviewer. Below is a point-by-point response to the Reviewer’s comments, which expands in detail on the points they raised and describes the revision that we have made to the manuscript. We are grateful for the valuable comments and hope that we have satisfactorily interpreted and addressed all concerns. We believe that we now have a significantly improved version of the manuscript for your consideration and hope that the revised manuscript will be suitable for publication in Agronomy. Changes made to the document are highlighted in yellow for Reviewer 2 and blue for Reviewer 3.
Open Review 3
Comments and Suggestions for Authors
The manuscript deals with the role of seaweed extract on the physiology and biochemistry of tomato plants grown under salinity stress. Soil salinity is a problem in many areas, therefore, studies with agents which could alleviate salinity stress and improve plant health conditions are needed.
The Authors should replace old references with newer ones. Done.
The comments are listed below:
L29-30: add number or % values for these parameters Done.
L76-80: start at the new paragraph and add at the beginning one or two introductory sentences related to antioxidant enzymes and non-enzymatic antioxidants in mitigation of various abiotic stresses (e.g. this reference: https://doi.org/10.1016/j.scienta.2022.110988). The recommended article was revised, and information regarding the enzymatic activity was included.
L174: 46 DAG – in the Fig. 1 the second phase starts in 48 DAG. Done.
L176-178: according to the Fig. 1, fertilization was also carried out in 23 DAG – add to the text. Done.
L191: indicate how many repetitions for each analyzed parameter were performed? Done.
L361: p ≤ 0.001 Done.
L368: add values of examined parameters for different treatments in this paragraph. Done.
L387-388: number instead proportion Done.
L437-444: add values of these parameters Done.
L484-498: add values of these parameters. Done.
L484 and L488: salinity stress without italics. Done.
L498-502: these statements are suitable for Discussion. The statements were moved to the Discussion section.
L507-509: rephrase this sentence to passive voice. Done.
L549: attraction Done.
L556: mine nutrients – rephrase Done.
L609: A. nodosum in full name when it appears for the first time in the text Done.
L669: reduced acquisition – according to the Fig. 4 it is enhanced acquisition Done.
L673: Na+ Done.
L675: Bougainvillea in italics Done.
L691: ‘which have antioxidant properties’ instead ‘which are a source of antioxidant compounds’ Done.
L718-752: shorten these two paragraphs and compare the results from described publications with CAT and SOD activity determined in this study. Done.
L765: according to the Fig. 4, reduction of Na+ and K+ Done.
For Table 3, 4, 5 and 6, add the text below these tables to the footnote. Done.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The manuscript is improved after the revision. The authors have made numerous changes and additions, as requested. In my opinion, it can now be accepted.
Author Response
The authors are grateful the valuable comments of the reviewer to improve the version of the manuscript. We appreciate for your consideration by acceptance of the publication in Agronomy.
Reviewer 2 Report
In my opinion, the manuscript is significantly improved and it is undoubtedly suitable for publication in Agronomy.
Author Response
The authors are grateful the valuable comments of the reviewer to improve the version of the manuscript. We appreciate for your consideration by acceptance of the publication in Agronomy.
Reviewer 3 Report
The manuscript has been corrected according to most of the comments. However, there are still some points which have to be corrected and clarified. The detailed comments are listed below:
L94-107: as it was stated previously, add information that antioxidant enzymes and non-enzymatic antioxidants are also engaged in mitigation of various abiotic stresses (e.g. pesticides, heavy metals, climatic conditions), reference: https://doi.org/10.1016/j.scienta.2022.110988
L233 and L279: indicate clearly in how many repetitions of analyzed parameters were determined. It was stated 15 plants for each treatment but does it means 15 determinations were performed for each parameter?
Author Response
The authors again appreciate the reviewer's comments to improve the writing.
L94-107: as it was stated previously, add information that antioxidant enzymes and non-enzymatic antioxidants are also engaged in mitigation of various abiotic stresses (e.g. pesticides, heavy metals, climatic conditions), reference: https://doi.org/10.1016/j.scienta.2022.110988
Online 98-101. A paragraph on the information requested by the reviewer is attached to the introduction. The information presented is very general and include 3 references. We hope to comply with what was requested by the reviewer.
L233 and L279: indicate clearly in how many repetitions of analyzed parameters were determined. It was stated 15 plants for each treatment but does it means 15 determinations were performed for each parameter?
In line 254. the information was incorporate (All biochemical measurements were performed in six replicates (each replicate consisted of a mix of two plants)
In line 354. Na+, K+, and Cl- concentrations in plants. All determinations were carried out in triplicate (each replicate consisted of a mix of five plants).
Author Response File: 
Author Response.pdf
