Growth, Phytochemicals, and Antioxidant Activity of Kale Grown under Different Nutrient-Solution Depths in Hydroponic

Round 1

Reviewer 1 Report

The reader is correctly introduced to the topic of work and the problems that are to be indicated are pointed out.

Methodology describes the methods which are suited and adequately described.  The experiments are properly planned and executed.

Analysis of the results is thorough and well argued.

The author(s) also compare obtained results with the experiments and results of other previous studies on the related subject.

My general opinion about the manuscript is positive, and for this reason I recommend it for publication.

Author Response

Dear editor and reviewers

Re: Manuscript ID: horticulturae-2105214 and Title: Growth, Phytochemicals and Antioxidant Activity of Kale Grown under Different Nutrient Solution Depths in Hydroponic.

Thank you very much for your kind letter, along with the constructive comments of four reviewers regarding our manuscript entitled “Growth, Phytochemicals and Antioxidant Activity of Kale Grown under Different Nutrient Solution Depths in Hydroponic” (Manuscript number: horticulturae-2105214). We have revised the manuscript after thoroughly considered all the comments and suggestions of reviewers. Appended to this letter is our point-by-point response to the comments raised by the reviewers. Based on the instructions provided in your letter, revisions in the text are shown using red highlight for additions.

We would love to thank you for allowing us to resubmit a revised copy of the manuscript and we highly appreciate your time and consideration.

Sincerely,

Dr. Houcheng Liu

College of Horticulture, South China Agricultural University ([email protected])

RESPONSES TO REVIEWERS’ COMMENTS

#Reviewer 1:

Q1: The reader is correctly introduced to the topic of work and the problems that are to be indicated are pointed out.

Methodology describes the methods which are suited and adequately described.  The experiments are properly planned and executed.

Analysis of the results is thorough and well argued.

The author(s) also compare obtained results with the experiments and results of other previous studies on the related subject.

My general opinion about the manuscript is positive, and for this reason I recommend it for publication.

Response：Thank you so much for your sincere comments. We have modified this manuscript in detail.

Author Response File: Author Response.docx

Reviewer 2 Report

This is a valuable contribution to the field.

Line 21: Please, add the word "total" to the description of glucosinolates, to differentiate them from indoles and aliphatics

Line 106: How much seeds were approximately used in each sponge cube (g)?

Line 152: Delete (acetone:alcohol) in parentheses, it is understandable that the ratio (1:1) refers to the mixture.

Line 248: Please, make sure if it is 500 mL or uL

Line 257: Distilled water or HPLC water

Line 600: I suggest correlating the discussion of glucosinolates contents in Kale with the presence of signaling molecules (ROS, H2O2) and the subsequent gene activation.

Line 615: The conclusion is very general and similar to abstract. I recommend that you explain about possible applications or future work.

Author Response

Dear editor and reviewers

Re: Manuscript ID: horticulturae-2105214 and Title: Growth, Phytochemicals and Antioxidant Activity of Kale Grown under Different Nutrient Solution Depths in Hydroponic.

Thank you very much for your kind letter, along with the constructive comments of four reviewers regarding our manuscript entitled “Growth, Phytochemicals and Antioxidant Activity of Kale Grown under Different Nutrient Solution Depths in Hydroponic” (Manuscript number: horticulturae-2105214). We have revised the manuscript after thoroughly considered all the comments and suggestions of reviewers. Appended to this letter is our point-by-point response to the comments raised by the reviewers. Based on the instructions provided in your letter, revisions in the text are shown using red highlight for additions.

We would love to thank you for allowing us to resubmit a revised copy of the manuscript and we highly appreciate your time and consideration.

Sincerely,

Dr. Houcheng Liu

College of Horticulture, South China Agricultural University ([email protected])

RESPONSES TO REVIEWERS’ COMMENTS

#Reviewer 2:

Q1: Line 21: Please, add the word "total" to the description of glucosinolates, to differentiate them from indoles and aliphatics

Response：Thank you for your professional suggestion. We have revised the manuscript accordingly.

Please find it in Line 21.

Q2: Line 106: How much seeds were approximately used in each sponge cube (g)?

Response：We apologize that the process of seeding was not described clearly. We only put one seed for each sponge cube.

Q3: Line 152: Delete (acetone:alcohol) in parentheses, it is understandable that the ratio (1:1) refers to the mixture. Line 248: Please, make sure if it is 500 mL or uL. Line 257: Distilled water or HPLC water

Response：Thank you for your professional suggestion. We are very sorry for our careless mistake and have revised the manuscript accordingly. Please see it in Line 162, 279 and 287.

Q4: I suggest correlating the discussion of glucosinolates contents in Kale with the presence of signaling molecules (ROS, H2O2) and the subsequent gene activation.

Response： Thank you so much for your valuable and helpful suggestions to improve our manuscript. We have revised the manuscript accordingly. Please see it in Line 648-651.

Q5: The conclusion is very general and similar to abstract. I recommend that you explain about possible applications or future work.

Response：Thank you so much for your valuable suggestions to improve our manuscript. We have revised the manuscript accordingly. Please see it in Line 668-671.

Author Response File: Author Response.docx

Reviewer 3 Report

Paper merits the publication in the present form. Introduction, experiemental conditions as well as results and discussion are clearly presented  and in my opinion consit all necessary information. 

Author Response

Dear editor and reviewers

Re: Manuscript ID: horticulturae-2105214 and Title: Growth, Phytochemicals and Antioxidant Activity of Kale Grown under Different Nutrient Solution Depths in Hydroponic.

Thank you very much for your kind letter, along with the constructive comments of four reviewers regarding our manuscript entitled “Growth, Phytochemicals and Antioxidant Activity of Kale Grown under Different Nutrient Solution Depths in Hydroponic” (Manuscript number: horticulturae-2105214). We have revised the manuscript after thoroughly considered all the comments and suggestions of reviewers. Appended to this letter is our point-by-point response to the comments raised by the reviewers. Based on the instructions provided in your letter, revisions in the text are shown using red highlight for additions.

We would love to thank you for allowing us to resubmit a revised copy of the manuscript and we highly appreciate your time and consideration.

Sincerely,

Dr. Houcheng Liu

College of Horticulture, South China Agricultural University ([email protected])

RESPONSES TO REVIEWERS’ COMMENTS

#Reviewer 3:

Q1:Paper merits the publication in the present form. Introduction, experiemental conditions as well as results and discussion are clearly presented and in my opinion consit all necessary information.

Response：Thank you so much for your sincere comments. We have modified this manuscript in detail.

Author Response File: Author Response.docx

Reviewer 4 Report

The present article have some serious concern  in experiment , Author should firstly justify

-219- Remove an  from an 80 ℃

-Fig.3.  Agrochemical traits have ben improved in  De-2 . as per your figure (Fig. 3. A,B,C,D,E) and also in Fig 4, De-2 treatment have significant effect, But in  Fig.5  contents of  soluble sugar and  proteins De-3 treatments were more significant.

Even in 5.B and Fig 5D De-2 treatment have least contents. This is surprising

-Line 329-  The vitamin C content of kale slightly reduced by 9% under De- 329 1, and markedly reduced by 29% under De-2 (Fig. 5B)  and Line 333-334 No obvious difference was observed in the antioxidant activities such as DPPH and FRAP, and the contents of antioxidant compounds such as total polyphenols and flavonoids in kale among all treatment-

But how it is possible when Vit-c or Ascorbic acid reduced and no effect observed in the antioxidant activity. Author have not done this experiment carefully. Please explain-

Author Response

Dear editor and reviewers

Re: Manuscript ID: horticulturae-2105214 and Title: Growth, Phytochemicals and Antioxidant Activity of Kale Grown under Different Nutrient Solution Depths in Hydroponic.

Thank you very much for your kind letter, along with the constructive comments of four reviewers regarding our manuscript entitled “Growth, Phytochemicals and Antioxidant Activity of Kale Grown under Different Nutrient Solution Depths in Hydroponic” (Manuscript number: horticulturae-2105214). We have revised the manuscript after thoroughly considered all the comments and suggestions of reviewers. Appended to this letter is our point-by-point response to the comments raised by the reviewers. Based on the instructions provided in your letter, revisions in the text are shown using red highlight for additions.

We would love to thank you for allowing us to resubmit a revised copy of the manuscript and we highly appreciate your time and consideration.

Sincerely,

Dr. Houcheng Liu

College of Horticulture, South China Agricultural University ([email protected])

RESPONSES TO REVIEWERS’ COMMENTS

#Reviewer 4:

Q1: Remove an from an 80 ℃

Response：Thank you so much for your valuable suggestions to improve our manuscript. We have revised the manuscript accordingly. Please see it in Line 243.

Q2: -Fig.3.  Agrochemical traits have been improved in De-2. as per your figure (Fig. 3. A,B,C,D,E) and also in Fig 4, De-2 treatment have significant effect, But in Fig.5 contents of soluble sugar and  proteins De-3 treatments were more significant. Even in 5.B and Fig 5D De-2 treatment have least contents. This is surprising

Response：Thank you for your comments. There might be due to dilution effects, the biomass of crop usually was inversely proportional to its nutrition quality. In this study, the De-2 significantly increased kale growth but decreased soluble sugar content when compared with De-3. No obvious difference was observed in soluble proteins among all treatments. 

Q3: -Line 329- The vitamin C content of kale slightly reduced by 9% under De- 3, and markedly reduced by 29% under De-2 (Fig. 5B) and Line 333-334 No obvious difference was observed in the antioxidant activities such as DPPH and FRAP, and the contents of antioxidant compounds such as total polyphenols and flavonoids in kale among all treatment-

But how it is possible when Vit-c or Ascorbic acid reduced and no effect observed in the antioxidant activity. Author have not done this experiment carefully. Please explain-

Response：Thank you so much for your valuable comments. Ascorbic acid is an antioxidant in plant, however the biosynthesis response of ascorbic acid to abiotic factors might be different from other antioxidant compounds. And the DPPH, FRAP were significantly related to many antioxidant compounds, include ascorbic acid, and total polyphenols and flavonoids. So the changed trends of ascorbic acid was different from DPPH, FRAP and other antioxidant compounds.

Author Response File: Author Response.docx

Round 2

Reviewer 4 Report

Authors have  respond all the quarries and the article can be accepted in the present form