Helichrysum microphyllum subsp. tyrrhenicum, Its Root-Associated Microorganisms, and Wood Chips Represent an Integrated Green Technology for the Remediation of Petroleum Hydrocarbon-Contaminated Soils

Round 1

Reviewer 1 Report

Manuscript of Helichrysum microphyllum (Willd.) Cambess. subsp. tyrrhenicum Bacch., Brullo & Giusso, its root associated microorganisms, and wood chips: an integrated green technology for remediation of petroleum hydrocarbon-contaminated soils study was evaluated were to: i) test the applicability of H. tyrrhenicum for revegetation of substrate with weathered hydrocarbon contamination, ii) evaluate if the addition of wood chips as substrate amendment enhances hydrocarbon removal by the studied plant-microbe system. In order to achieve the aforementioned objectives, a multidisciplinary approach was employed, including evaluation of plant growth, soil microbial activity and abundance, as well as hydrocarbon degradation. This article is well written and already incorporated all the required corrections. However, some limitations need to be solved before further evaluation.

 

-          In complete sentence structure in the whole manuscript, difficult to understand what the author wants to say, so I recommend the author revise the whole manuscript's English.

- Abstract need to rewrite and add some numerical results.

- Title is very long can you reduce it?

-          In general, the introduction includes proper information and references, but little information and the corresponding reference are not considered relevant, which was pointed out in the document. 

 -          In the section on methods, phytochemical screening should be better described and/or supported by proper references.

-  Resolution of photo is not good.

- Where is the conclusion of this study? It is recommended to add 2-5 sentences at the end of manuscript as conclusion of this study. Please Add Conclusion section. Conclusion is very important part of paper.

- Define the abbreviation in whole article

-   How many samples were collected? Need to write about a number of samples.

 It is unclear what are the different functions of the three different materials used.  

-          Please check typo and Italic name in all article.

 

 

Author Response

The authors wish to thank the reviewer for the raised questions. Please find below the point-by-point answers to reviewer’s comments. Revisions are shown as Track Changes in the revised version of the manuscript.

Reviewer’s Question: In complete sentence structure in the whole manuscript, difficult to understand what the author wants to say, so I recommend the author revise the whole manuscript's English.

Authors’ Answer: The whole manuscript was accurately checked, and the text was clarified where necessary.

Reviewer’s Question: Abstract need to rewrite and add some numerical results.

Authors’ Answer: The abstract was corrected, and numerical results added as requested.

Reviewer’s Question: Title is very long can you reduce it?

Authors’ Answer: The title was shortened as requested.

Reviewer’s Question: In general, the introduction includes proper information and references, but little information and the corresponding reference are not considered relevant, which was pointed out in the document.

Authors’ Answer: References were carefully checked, and we think that all the cited studies could be important for understanding the background of our study.

Reviewer’s Question: In the section on methods, phytochemical screening should be better described and/or supported by proper references.

Authors’ Answer: Methods were integrated in paragraph 2.3 as requested.

Reviewer’s Question: Resolution of photo is not good.

Authors’ Answer: The quality of photos were improved as requested.

Reviewer’s Question: Where is the conclusion of this study? It is recommended to add 2-5 sentences at the end of manuscript as conclusion of this study. Please Add Conclusion section. Conclusion is very important part of paper.

Authors’ Answer: The conclusion section was added, and conclusions of the study provided as requested.

Reviewer’s Question: Define the abbreviation in whole article.

Authors’ Answer: All abbreviation in the manuscript, supplementary material, and figures were carefully checked and corrected as requested.

Reviewer’s Question: How many samples were collected? Need to write about a number of samples.

Authors’ Answer: The numbers of samples collected from the studied site were added in line 143. Moreover, additional details were provided for samples collected at the end of the greenhouse test in paragraph 2.2.

Reviewer’s Question: It is unclear what are the different functions of the three different materials used.

Authors’ Answer:

In our study were analysed plant growth on three different substrates: a contaminated substrate with (WCAM) and without (UNAM) wood chips in order to test the effect as amendment. We also used a commercial garden (GARD) preparation as optimal growth substrate. For each plot, we analysed three different matrices: rhizosphere, bulk substrate, and deep substrate. They were separately analysed since specific interactions between plants and root-associated microorganisms take place in the rhizosphere. Thus, rhizosphere is a microhabitat substantially different from the bulk soil in terms of chemical-physical and microbiological properties. In this study, we also decided to separately analyse the bulk and deep substrates based on the hypothesis that the substrates under the plant roots (deep substrate) could have specific chemical-physical characteristics, which could have important effects on the degradation process (e.g., lower oxygen in the deep substrate).

Reviewer’s Question: Please check typo and Italic name in all article.

Authors’ Answer: The whole manuscript and supplementary material were accurately checked and corrected as requested.

Reviewer 2 Report

Dear authors,

The area of your research is interesting. However, the article is not in scientific form.

Check title. Scientific name used is very big.

There is no resulted presented in the abstract.

Section 2.2.....No mention about how sampling was done?? Which instruments were used??

Section 3.2.....Highlighting the genus and species in a big way in section title.

# I agree that the article has some value but the way of presentation does not meet the standard of the Journal.

The presentation of the results is not clear or rather very poor. First of all the volume of data is not satisfactory. And, authors highlighted the supplementary data rather than the main outcomes of the study.

Discussion: Sub-headings must be added.

Conclusion section is missing.

Author Response

The authors wish to thank the reviewer for the raised questions. Please find below the point-by-point answers to reviewer’s comments. Revisions are shown as Track Changes in the revised version of the manuscript.

Reviewer’s Question: The area of your research is interesting. However, the article is not in scientific form. I agree that the article has some value but the way of presentation does not meet the standard of the Journal. The presentation of the results is not clear or rather very poor. First of all the volume of data is not satisfactory. And, authors highlighted the supplementary data rather than the main outcomes of the study.

Authors’ Answer: We agree with the reviewer that several more questions could be raised on the subject. However, we decided to concentrate our experimental effort on a single question and to analyse the system by a set of chemical and biological parameters with a careful statistical analysis of data in order to explore the different components of the system under controlled conditions. This is the reason why, as pointed by the reviewer, we have several supplementary tables, where raw data supporting reported results can be found (as suggested by the Journal instruction). In order to show data in a more readable form, results and their statistics were all presented in a synthetic form in tables and figures of the manuscript, and we systematically cited both supplementary material and manuscript tables and figures all over the text. Despite the limitations of a test under greenhouse-controlled conditions, we think that the obtained results could be considered innovative in terms of exploited plant species, tested amendment, and addressed contaminants. According to the criticisms raised by the reviewer, we revised the manuscript stressing in the conclusion section the limits of the present work, which should be exclusively considered the premise for future studies.

Reviewer’s Question: Check title. Scientific name used is very big.

Authors’ Answer: The title was shortened as requested.

Reviewer’s Question: There is no resulted presented in the abstract.

Authors’ Answer: The abstract was revised, and numerical results added as requested.

Reviewer’s Question: Section 2.2. No mention about how sampling was done?? Which instruments were used??

Authors’ Answer: More details on the sampling procedure were added in the text.

Reviewer’s Question: Section 3.2. Highlighting the genus and species in a big way in section title.

Authors’ Answer: the title of section 3.2 was modified omitting to mention again the species name.

Reviewer’s Question: Discussion: Sub-headings must be added.

Authors’ Answer: We carefully reconsidered to divide the discussion into subsections as suggested by the reviewer, but we preferred to maintain a single section as envisaged by the journal template. Moreover, we consider very important to provide an integrated comment of the results, thus allowing the reader to understand interrelations among the different components (plant /microbes /contaminants) of the process.

Reviewer’s Question: Conclusion section is missing.

Authors’ Answer: The conclusion section was added, and conclusions of the study provided as requested.

Reviewer 3 Report

Comments, suggestions and advice have been included in the file text here attached.

Comments for author File: Comments.pdf

Author Response

The authors wish to thank the reviewer for text revisions which improved its readability. All the suggested corrections were introduced in the revised version of the manuscript.

Reviewer 4 Report

The article “Helichrysum microphyllum (Willd.) Cambess. subsp. tyrrhenicum
Bacch., Brullo & Giusso, its root associated microorganisms, and wood chips:
an integrated green technology for remediation of petroleum
hydrocarbon-contaminated soils” is very well organized with a clear and precise
objective. The introduction is very explanatory and the use of the plant species
Helichrysum microphyllum is very well justified. The results are shown in an
excellent way with tables and graphs where the significant differences among
treatments are clearly observed. The discussion is well argued and the results
compared with updated papers

.With these results at the greenhouse scale, it would now be very useful to test this plant in field conditions.

Author Response

The authors wish to thank the reviewer for taking the time to evaluate our manuscript and for appreciating our study.

Round 2

Reviewer 1 Report

Accept in present form

Author Response

The authors wish to thank the reviewer for taking the time to evaluate our manuscript and for appreciating our study.

Reviewer 2 Report

The level of revision made is not satisfactory. The scientific data set is lacking again and the presentation of results is very poor.

Author Response

Please find below the point-by-point answers to reviewer’s comments, explaining the rationale of our study and manuscript structure.

• The introduction summarizes current literature justifying the choose of the plant species Helichrysum microphyllum tyrrhenicum and wood chips as amendment. Moreover, we explained the limits of current technology for bioremediation of soils contaminated by weathered petroleum hydrocarbons.
• The addressed objective was clearly stated, and the experimental design was presented in a rigorous way detailing all the experimental steps: setting up of the greenhouse test, test monitoring, sample collection, and methods used for the analyses of samples by a wide panel of chemical and biological parameters.
• Experimental design and addressed question were in line with current literature, including other greenhouse experimentations recently published by Agronomy. Moreover, the aim of the study was coherent with the objective of the special issue “Bioremediation and Management for Sustainable Agriculture”.
• Data were subjected by accurate univariate and multivariate statistical analyses, in line with current literature.
• As suggested by the Journal instruction, raw data supporting obtained results were presented in several supplementary tables. Moreover, results and their statistics were all shown in a more readable form in the tables and figures of the manuscript.
• Overall, this experimental approach allows us to clearly highlight the intrinsic variability deriving by the exploitation of a real substrate with a weathered contamination, but also to identified results robustly supported by a strong statistical significance. Thus, conclusions on the effects of the treatment on the system under controlled experimental conditions were exclusively drawn based on statistically significant differences between amended and unamended conditions.
• Results were compared with updated literature and interrelations among the different components (plant /microbes /contaminants) of the process carefully explained.
• The conclusion underlines the innovative aspects of the technology but, aware of the limitations of a greenhouse-scale test, we clearly stressed the need to validate the technology under real field conditions.