Silicon Application Induced Alleviation of Aluminum Toxicity in Xaraés Palisadegrass
, Marcio Mahmoud Megda 4, Nathália Cristina Marchiori Pereira 1, Monique Oliveira Luchetta 1, Caio Augusto Tritapepe 1, Marcelo Rinaldi da Silva 1, Arshad Jalal 1 and Marcelo Carvalho Minhoto Teixeira Filho 1,*Round 1
Reviewer 1 Report
The reviewers’ comments have been addressed
Author Response
Dear Academic Editor,
We would like to express our gratitude for the reviewers who took the time to provide such a thorough review of our manuscript. We believe that the changes suggested have made our manuscript much more direct and much easier to follow. We have addressed all of the concerns raised and provide a point-by-point answer on how we handled each comment provided. Our answers will be in italic and underlined right after each comment.
English language and style are fine/minor spell check required
R: We revised the English language and made as few corrections as needed. Thank you.
Again, our most sincere gratitude to you and the reviewers who took time from their busy schedule to help us making this manuscript a better paper. We hope that we have answered every inquiry to your satisfaction and also hope that you will find this version of publishable quality. Should you find that further work is needed, we will also gladly do it in a timely manner.
Very best,
Authors
Author Response File: 
Author Response.docx
Reviewer 2 Report
After re-reading the article I didn't find any new flaws. Authors responded to most of comments, corrections were made. Authors provided explanation to all the doubts. Also, I would like to stress the positive impact of calculated and added translocation factors – these values supported other observations and provided some new conclusions.
As I noticed in my previous review during conversion of files a formatting style - deletion of text, marked with strikethrough tool, was lost. That made some comments not understandable to Authors. Once again I would like to clarify these comments (with updated line numbers):
Line 21: concentrations was evaluated – word “was” should be deleted
Line 59: soil type – please use singular
Line 61: when you use “e.g.” you don’t have to write “among others” at the end of the sentence
Line 184: I meant that Authors should unify and use full names or shortcuts for all the elements. Now, in case of nitrogen full name is used but for others - only shortcuts. I don’t think that full names are needed here.
Line 303: “Fe” was included in the group of factors that responded non-lineary; in this case response was linear (also, it was not mentioned in references in brackets), so word “Fe” should be deleted
Line 473: see comment for line 61
Comments for author File: 
Comments.pdf
Author Response
Dear Academic Editor,
We would like to express our gratitude for the reviewers who took the time to provide such a thorough review of our manuscript. We believe that the changes suggested have made our manuscript much more direct and much easier to follow. We have addressed all of the concerns raised and provide a point-by-point answer on how we handled each comment provided. Our answers will be in italic and underlined right after each comment.
Again, our most sincere gratitude to you and the reviewers who took time from their busy schedule to help us making this manuscript a better paper. We hope that we have answered every inquiry to your satisfaction and also hope that you will find this version of publishable quality. Should you find that further work is needed, we will also gladly do it in a timely manner.
Very best,
Authors
REVIEWER 2
After re-reading the article I didn't find any new flaws. Authors responded to most of comments, corrections were made. Authors provided explanation to all the doubts. Also, I would like to stress the positive impact of calculated and added translocation factors – these values supported other observations and provided some new conclusions.
R: We appreciate all the reviewer suggestions and comments. Thank you.
As I noticed in my previous review during conversion of files a formatting style - deletion of text, marked with strikethrough tool, was lost. That made some comments not understandable to Authors. Once again I would like to clarify these comments (with updated line numbers):
Line 21: concentrations was evaluated – word “was” should be deleted
R: Change made. Thank you.
Line 59: soil type – please use singular
R: Change made. Thank you.
Line 61: when you use “e.g.” you don’t have to write “among others” at the end of the sentence
R: Change made. Thank you.
Line 184: I meant that Authors should unify and use full names or shortcuts for all the elements. Now, in case of nitrogen full name is used but for others - only shortcuts. I don’t think that full names are needed here.
R: Change made. Thank you.
Line 303: “Fe” was included in the group of factors that responded non-lineary; in this case response was linear (also, it was not mentioned in references in brackets), so word “Fe” should be deleted
R: Change made. Thank you.
Line 473: see comment for line 61
R: Change made. Thank you.
We appreciate all the reviewer suggestions and comments. We hope that this version has met the expectations of the reviewer. Thank you.
Author Response File: Author Response.docx
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
The manuscript deals with "mitigation of aluminum toxicity in Xaraes palisadegrass by application of silicon.
Using silicon is a common method to reduce the toxicity of heavy metals on plants (https://doi.org/10.3390/plants9040500).
1. Page 1, Line 14; "acidic soils which need a sustainable..." Should be corrected as "acidic soils which needs a sustainable.."
2. Page 1, Line 21; "...was evaluated in nutrient solutions containing 1mM Al in two sampling dates (two forage cuts)..." Should be corrected as "as well as with nutrient solutions containing 1mM Al in two sampling dates (two forage cuts).
3. Page 1, Line 27; "..Si in solution decreased Al translocation to shoots.." Mention the values.
4. Write keywords alphabetically.
5. Page 16, Line 372; "...used was ground quartz.." Size of substrate? 1 to 2 mm?
Reviewer 2 Report
Silicon application induced alleviation of aluminum toxicity in Xaraes palisadegrass
Comments:
Manuscript describes results of simple experiment (one tested plant, one variable – concentration of Si given in five variants). The tested plant – Xarases palisadegrass is one of the models from Urochloa sp., grasses used as pasture material introduced and commonly used in some regions of the Southern America, what makes the observations described in given manuscript interesting only for part of the society. I don’t see high, worldwide scientific soundness, however results may be very important for scientists and forage producers from Brazil.
In the introduction authors gave some information about the researched component – aluminum. They wrote about its concentration in earth’s crust and explained the toxic effect for plants, but which concentrations are toxic and where they can be found? Also, I didn’t find the background of the study - if there is a local or general, worldwide problem with accumulation of aluminum (or its elevated levels due to the pollution) in soil. In paper there is detailed information about the previously described effects of Al and Si elevated concentrations in plants. Is it possible for authors to comment if any of these effects were observed also during the experiment?
The design of the experiment is simple, but proper. Many biological parameters were evaluated including number of tillers and leaves, shoot biomass, N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, Zn, Al and Si concentration in leaf tissue, Al and Si concentration in root tissue, NDF and ADF. I didn’t find information about number of technical repetitions of evaluated parameters (e.g. nutrient concentrations), although I noticed the information about biological repetitions – 4. Section Materials & Methods in my opinion should be given before results, to make the paper more understandable.
Results were presented in form of simple and readable graphs with extended description in text (in my opinion, it would be better to stress if the correlation was observed and if it was positive or negative rather than if it was linear or non-linear. If the relation between factors was not possible to name (e.g. for NDF) it was neglected in the description.
I suggest calculation of “roots to shoots translocation factor” for both Al and Si; this parameters and its comparison should visualize the accumulation, directions of translocation and relations of these two elements in plant tissues.
The given paper includes great number of references, authors provided 71 positions of literature: 39 of them were mentioned in the introduction section, 35 in the discussion and 6 in the materials and methods. Four of references are in Portuguese, 67 in English. Almost 40 papers were published in last 5 years, 53 were mentioned only once in the text. I found only one flaw with numeration – pos. 70.
Abstract contain 321 words, should be up to 200 as recommended by MDPI Agronomy guideline.
Overall merit of the described experiment is average, it is simple, but well planned and performed experiment with many results, which were properly commented and discussed with literature.
Detailed comments (with reference to particular line):
Line 3: Word Xaraés – should be unified in whole text, written with accent (like in line 67)
Lines 20-21: The study was conducted … with the effect of five concentrations was evaluated…
Line 21: authors write about five Si concentrations, but variant “0” is not containing Si, therefore probably it should not be included in the overall Si concentrations number and treated as a negative control. In text it is sometimes mentioned as “Si concentration” or “ctl”; see Fig. 6 B,D – should be unified.
Line 23: [is] Number; [should be] number
Line 45: [is] toxicity represented; [should be] toxicity is represented
Line 58: [is] being increasingly; [should be – as I understand] is being increasingly [or] is increasingly; also: did authors mean “adopted” or “adapted”?
Line 60: soil types
Line 62: among others
Lines 69-71: Sentence: “These factors … cultivation” – I don’t understand if authors write about combined toleration to spittlebugs and poorly drained soils, which increased cultivation of Xaraés; or increased cultivation in poorly drained soils as an effect of mentioned factors (sentence should be rewritten).
Line 92: [is] It would be possible; [should be] It might be possible
Line 96: [is] in special; [should be] especially
Lines 99-100: repetition – “uptake”
Lines 101-102: repetition – “affect composition”
Lines 119-126, Section Results, 2.1: there is no comment about NDF changes;
Line 181: Mg, S, Cu, Fe and Mn
Line 218: [is] among leaf Si concentration and leaf K, Ca … concentrations; [should be] among leaf Si, K, Ca … concentrations
Line 231, Fig. 6: please unify - label “ctl” or “”0”, as compared with the text
Lines 280-281: Is Al stored in roots in non-toxic form (which one?) or in general, storage of Al in roots is less toxic (non-toxic) for plant than storage in shoots? (should be explained)
Line 289: citation 70 – appropriate order of citations should be applied (this paper should have number 46)
Line 293: “content” – of what?
Line 343: among others
Line 359: [is] 30 °C, with average air relative humidity; [should be] 30°C; with average air relative humidity
Lines 372-374: the sentences should be writen with more scientific language
Line 410: Authors should specify if the shoots and roots were collected in the 70 DAT or later
Line 426: N,P, K… or Nitrogen, phosphorus, potassium…
Line 441: please use round brackets. The description [1] may be misinterpreted as citation of paper nº1 from reference list.
Line 442: [is] Engenvectors; [should be] Eigenvectors
Line 443: [is] Eingenvalue; [should be] Eigenvalue
Lines 447-458: conclusions are mostly direct repetitions of sentences from the text or were repeated in abstract. For example: lines 450-452 vs. 27-29, 452-453 vs. 316-317, 454 vs. 339, 455-457 vs. 351-353. Should be improved.
Comments for author File: Comments.pdf
