Insights into Cadmium-Induced Morphophysiological Disorders in Althea rosea Cavan and Its Phytoremediation through the Exogeneous Citric Acid

Round 1

Reviewer 1 Report

 

1.      I recommend including the abstract, general description of methods, treatments, or evaluations, main results expressed with values and statistical significance, and the conclusion of the evaluation or analysis of the experimental results.

2. Please show the novelty in the abstract.

3.    Avoid repetition of keywords in the title.

4. Put reference at the end of this sentence "In the past few decades, there has been a great deal of concern about the environmental degradation that toxic metal buildup in the soil and water has caused."

5. Authors used old references. So, please put this update reference at the end of this sentence "Hazardous materials such as heavy metals, pesticides, herbicides and persistent organic pollutants have been found in air, water and soil."

REFERENCE: Aioub, A. A., Li, Y., Qie, X., Zhang, X., & Hu, Z. (2019). Reduction of soil contamination by cypermethrin residues using phytoremediation with Plantago major and some surfactants. Environmental Sciences Europe, 31(1), 1-12.

6. Using subscript for H2O2 and O2.

7. Put reference at the end of this sentence "Many plant species have been found to have fundamental HM tolerance mechanisms." and this sentence "Many plant species with low levels of metal uptake and subsequent transfer to plants' above-ground tissues have high tolerance for trace metals.". Also, "Hyperaccumulators are plants that can transport heavy metals and have a high potential for accumulation."

8. Delete dot in line 68.

9. Please put this reference after this sentence " Phytoremediation, a biological approach, is used to clean up polluted soil as it is economical and extensively applicable."

REFERENCE: Aioub, A. A., Zuo, Y., Aioub, A. A., & Hu, Z. (2021). Biochemical and phytoremediation of Plantago major L. to protect tomato plants from the contamination of cypermethrin pesticide. Environmental Science and Pollution Research, 28(32), 43992-44001. 

10. Please show the hypothesis in the end of introduction. 

11. Why authors used (100 and 200 mg/kg) from Cd? Do you reference about the concentration that used in the experiment?

12. Put the contents of modified Hoagland's solution between [   ].

13. I have been confused about your experiment design. In methodology, authors used two concentrations from Cd. However, in the table, you showed five treatments. you don't show clearly these treatments. So, I strongly recommend explaining more about your experiment and clarifying how many treatments and what is the treatments. As well as, authors write in table 2, 100 and 200 mg. authors must write 100 and 200 mg/kg not mg only.

14. I don't know what is the difference between control and treatment 1. 

15. The design of tables is not good and the resolution of the figures badly.

16. Why don't use different periods to collect samples? This makes the results more realistic     

17. Discussion sections need more citations.

18. English revision is required.

Author Response

We are really thankful for your valuable suggestions, and we hope that by following your instructions the quality of paper is really improved. 

Author Response File: Author Response.docx

Reviewer 2 Report

The main idea of this study is clear but there are some questions and discussion need to be clarified as the following.

1. BAF is mentioned in the abstract, but only BAC and BCF are included in “materials and methods”;

2. Line 208 should be changed to p<0.05;

3. Tables 1 and 2 should be placed at the corresponding positions in “materials and methods”, not under figure 1;

4. 3.1. Agronomic traits should be changed to “variation of growth”;

5. Space between numerical units; Fig3A-E instead of Fig3a-e; Please confirm that Fig 6a or Fig 6A in 348-358 should be Fig 6; There is one more in front of line 418 [53];

6. There are too many descriptions in 373-413, and the logic of the discussion needs to be adjusted. For example, it is more appropriate not to put the sentence 411-413 at the end of the paragraph; In addition, the discussion part is discussed according to the test indicators, which seems to be of weak relevance. It is suggested that the title names “Plant Biomass” and “Chlorophyll and carotinoids” should be changed.

7. It is suggested that 4.4Cd accumulation can be changed to 4.2, and the previous 4.2 and 4.3 can be changed to 4.3 and 4.4;

8. The latest references in "References" in recent years are relatively few, especially the references in Introduction.

Author Response

We are really thankful for your valuable suggestions, and we hope that by following your instructions the quality of paper is really improved. 

Author Response File: Author Response.docx

Reviewer 3 Report

This article studies the effect of two different doses of Cd with and without citric acid on A. rosea.

My main concern about this article is the correct use of the term phytoextraction. This plant is quite far to be considered for phytoextraction. Their levels of accumulation are quite far to be considered for this purpose. Please have a look at this (http://dx.doi.org/10.1016/j.ecoenv.2015.12.023, . doi:10.1016/j.envpol.2007.05.024, http://dx.doi.org/10.1016/j.chemosphere.2016.12.116)

Another important missing data is the availability of Cd in the soil. Although you add Cd to the soil its pH is quite alkaline, therefore their availability is low. This is a key aspect of this study and you just mention it at the end of the discussion. Moreover usually citric acid decrease soil pH, (you should analyze this), and at this alkaline pH, a small pH change can improve nutrient availability and that also helps to better biomass data.

Moreover, Cd levels in the different plants are not considered toxic for them, so morphological differences must not be high. Check Cd toxicity levels in plants.

I recommend firstly presenting Cd accumulation in plants and then the rest of the results…just to justify the rest of the data that depend on the Cd accumulation in roots and aerial part.

Other comments:

Line 61. You have to distinguish between accumulator and hyperaccumulator plants. Revise Baker 1981.

Line 188. How did you do the digestion on the samples? microwave? Digi press? add the information

Table2. Is it correct Control has +citric acid? check this

Moreover, I think it will be more intuitive to name the treatments as T0 and T0+, T1 and T1+, and T2 and T2+

Table 1. What about soil nutrients? soil moisture content is right?

Say something about relative water content in the result and discussion.

 

Section 3.8. Rewrite this section. Clarify the most important results of the analysis.

Author Response

We are really thankful for your valuable suggestions, and we hope that by following your instructions, the quality of the paper is really improved. 

Author Response File: Author Response.docx

Reviewer 4 Report

The effects of citric acid on the plant Althea rosea in Cd-polluted soil are described in the text. Although the study's description and its findings are suitable for publishing, the presentation is inadequate. The paper must undergo a thorough review before it can be published. The following are some errors and mistakes that authors should pay attention to.:

1. In the last paragraph of introduction there is not presented clearly the aim of study

2. There is a confusion between numeration of figures and the reference of them in text. In line 268 is mentioned Fig 3 but it is fugure 2, the same error is continue to the next figure.

3. The figure 5 and 6 have had wrong content. The caption mention R correlation and the figure is PCA.

4. Check the significant figures in the table 1

5. Review all the text for missing spaces between the number and units.

6. Review all the text to correct the chemical formulas presentation.

Author Response

We are really thankful for your valuable suggestions, and we hope that by following your instructions, the quality of the paper is really improved. 

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Accept

Author Response

The authors are thankful for approving our changes and recommending our paper for acceptance. 

Reviewer 3 Report

My main concern about this article is the correct use of the term phytoextraction. This plant is quite far to be considered for phytoextraction. Their levels of accumulation are quite far to be considered for this purpose. Please have a look about this (http://dx.doi.org/10.1016/j.ecoenv.2015.12.023, . doi:10.1016/j.envpol.2007.05.024, http://dx.doi.org/10.1016/j.chemosphere.2016.12.116)

Another important missing data is the availability of Cd in the soil. Although you add Cd to the soil its pH is quite alkaline, therefore their availability is low. This is a key aspect for this study and you just mention at the end of the discussion. Moreover usually citric acid decrease soil pH, (you should analyse this), and at this alkaline pH, a small pH change can improve nutrients availability and that also helps to better biomass data.

 

Moreover, Cd levels in the different plants are not considered toxic for them, so morphological differences must not be high. Check Cd toxicity levels in plants.

 

Revis the units nomenclature

Author Response

The authors are thankful for your valuable suggestions. We hope the paper is now really improved. 

Author Response File: Author Response.docx

Reviewer 4 Report

The manuscript is accepted for publication in the journal after minor revision of the text. In the uploaded text have been pointed out in the manuscript the points that authors should check. Based on the text, authors should revise the below:

1. Numbers and units need a space

2. Text and references need a space

3. In Table  1 check the decimal figures

4. In some chemical formulas the numbers need to be indices 

5. Review in the text and check the number of decimal figures in the percentages if it is appropriate.

6. In some units the number should be superscript. Check in the manuscript for some missings

7. In Line #382, check the footer if missing for some Table

8. In the text, first in mentioned the pearson correlation and after the PCA. It is preferealbe to change the Figures in text and the numbering (Fig. 5 become Fig. 6 and vice versa)

9. In Figure 3, The Chart E need a parenthesis "(E)".

10. The last figure in page 15 has no caprtion. Maybe it is graphical abstract. If yes, It is OK.

 

Comments for author File: Comments.pdf

Author Response

The authors are thankful for your precious comments and suggestions. We hope our paper is now really improved very much. 

Author Response File: Author Response.docx