Pteridium aquilinum (Dennstaedtiaceae), a Novel Hyperaccumulator Species of Hexavalent Chromium

Round 1

Reviewer 1 Report

This article can provide a reference for the selection of materials for hexavalent chromium contaminated phytoremediation and the application in the reproductive stage. Please make modifications and improvements according to the following suggestions：

1）This is a hydroponic experiment, which is far away from the real application of phytoremediation. In the introduction, the applicability of plant hydroponic experiments should be more described for hyperaccumulator species selection. 

2）In the last paragraph of the introduction, the purpose and significance of this study should be clearly stated.

3）'2.3 Quantification Cr VI in culture medium' and '2.5 Cr content in plant tissue and media culture' should be described together. 

4）Line chart is replaced by bar chart in Figure 1 and Figure 2. 

5）In Figure 3 and  Figure 4, there is no need to display the content value of the blank control.

6）In Line 203-205，not incresed after 168 h, this test just only persist 168h. 

7)  In order to understanding of the theme, sub-headings should be listed in the discussion. 

8) Please compare the ability of different ferns to absorb different heavy metals, such as arsenic and copper in discussion. 

 

Author Response

First reviewer's letter

In response to the comments made by the reviewer:

1) It is explained in detail both in the introduction and in the discussions the reason why in vitro and hydroponic cultures are used in the search for new accumulator species, which advantages have the types of cultures mentioned above and how from this type of bioassays have been found species that have been successfully applied in phytoremediation processes.

2) As was commented, the last paragraph of the introduction was restructured to make clear the aims and main results of this research and its importance. 

3) In the method, sections 2.3 and 2.5 were merged into a single section to make it clearer.

4) Figure 1 and 2 line chart was replaced by bar chart, since in the line chart format the data were unclear.

5) In figure 3 and 4 the blank control was not shown because it was confusing and did not provide information, as the reviewer noted.

6) In line 203-205 the drafting was corrected and it was effectively emphasized that the results and how they remained constant.

7) Sub-headings were added to the discussion in order to make the topics addressed clearer.

8) A comparison was made of the species worked with other species that accumulate chromium, which were scarce, and the fern P. vittata was taken up in the discussions due to its capacity to accumulate Cr and its exceptional capacity for arsenic.

All corrections were made and all comments were taken into account because of their great contribution to this work. Thank you and we remain attentive to the pertinent corrections.

 

The authors.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments to the author

Author has prepared Pteridium aquilinum (Dennstaedtiaceae), a novel hyper-accumulator species of hexavalent chromium.

The experimental studies need to be more systematic and scientifically should be provided in order to claim for strong enough to support so that, this article reader will get attract more attention about this article which are lacking this current form manuscript, especially

The author has reported in abstract and results and discussion which deals about chromium(VI) accumulated up to 915 mg of Cr• kg-1 DW, could you provide more details about compare with previously reported literature studies against with this proposed studie, the advantage this current studies?? How it’s improved from the previous one, what are the added advantage this proposed studies, this will be very important, so that this article can find more interesting details and clarity.

In the introduction section need to be more recent studies which deals about phytoremediation related work, author has extensively cited nearly 72 references but this has to be reduce and much more recent and relevant one.

Please showcase your experimental studies which providing about phytoremediation, so that this article reader will be paid more attention.

I have important concern about the determination and Quantification Cr(VI), in page number 3 section number 2.3, in my own experience chromium(VI) and 1, 5 diphenylcarbazide (DPC) in presence of acidic medium will form immediately violet colour complex, followed by this can be quantified using UV-visible spectrophotometer, However author should update the most recent reference to be specified place.

I suggest author has to provide schematic representation for mechanism of interaction with chromium(VI) and proposed materials, this will be very attractive to read this article reader, i suggest author has to showcase their current studies with conceptual illustration show case the interaction will be useful to this article reader information’s.

Comments for author File: Comments.pdf

Please see Comments and Suggestions for Authors

Author Response

Second reviewer's letter

In response to the comments made by the reviewer:

One of the most important comments was about the chromium accumulation capacity of gametophytes in these ferns. As was pointed out we mentioned the ability of gametophytes, but this information is not covered below so in discussions we added:

-The comparison of gametophytes with respect to other species of ferns that have also worked with this same phase, as there were no studies of accumulation with chromium we proceeded to compare with gametophytes accumulators of other metals.

-The implications of the gametophyte accumulation and its correlation with the accumulation capacities of the sporophytes.

-The advantage of working with gametophytes and testing their ability to accumulate heavy metals.

An exhaustive depuration of the bibliography was carried out, and redundant bibliography was eliminated; the introduction was where the bibliography was most reduced, however, because our study was compared with other researches, it was a difficult task to reduce the citations in the discussions. 

In order to make the importance of the research clearer, both the introduction and the discussions explain in detail the reason for using in vitro and hydroponic cultures in the search for new accumulator species, the advantages of the above mentioned types of cultures and how these types of bioassays have been used to find species that have been successfully applied in phytoremediation processes.

The method used for Cr VI quantification is further detailed, as well as discussing what could be the conditions that could affect the measurements and cause error in our analysis.

The last comment was to elaborate a scheme showing the interaction of chromium with plants, from its uptake to accumulation and why there is a low translocation of the metal to the leaves. The general mechanism of Cr accumulation is illustrated without going into much detail of the metabolic pathways involved as that was not the objective of this research. In addition, the added scheme was used to illustrate the gametophytic and sporophytic phase of P. aquilinum. 

All recommendations were corrected and all feedback was taken into account due to its assertiveness and that enriched this research. Thank you and we remain attentive to the pertinent corrections.

 

The authors.

Round 2

Reviewer 2 Report

Extensive editing of English language required,

Extensive editing of English language required, after sucessful  incorporation the manuscript can be considered for publication