Agropyron mongolicum Keng’s Growth in Response to Nitrogen Addition Is Linked to Root Morphological Traits and Nitrogen-Use Efficiency
Round 1
Reviewer 1 Report
The article “Agropyron mongolicum Keng’s growth in response to nitrogen 2 addition is linked to root morphological traits and nitrogen-use 3 efficiency” investigates the growth response of Agropyron mongolicum Keng to N fertilization and whether this response is related to root morphological traits and N-use efficiency.
The experiment was conducted in a rigorous manner and the article is clear and well written, here are some of my suggestions
l. 74-79 I suggest to delete this part since it is appropriate for M&M but not for introduction
l. 287 I suggest to read and cite also this article https://doi.org/10.3390/agriculture9120252
I suggest stressing more the conclusions, especially with regard to the potential application of the results of the study
Author Response
Dear reviewer,
Thank you for such positive comments and your valuable suggestions. Your comments are very helpful in improving the quality of our manuscript (MS). We have carefully revised the manuscript and provided specific responses to each of the comments in blue. Revised portions are marked in the revised MS. Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Comments on the manuscript “Agropyron mongolicum Keng’s growth in response to nitrogen addition is linked to root morphological traits and nitrogen-use efficiency” by Aiyun Xu, Xing Wang, Xiaojia Wang, Dongmei Xu and Bing Caosubmitted to Agronomy MDPI.
Formulation of the scientific problem:
The authors state that they are checking if N addition is related to root morphological traits and N-use efficiency (line 16 and 68-69). In my opinion this is not properly formulated scientific problem. The authors are looking for the response of A. mongolium to different doses of N. The response is examined by observations of some of the morphological traits (only in root as root surface area, volume, length, forks number), as well as by physiological parameters such as N-uptake efficiency and utilisation ( represented by N metabolic enzymes activities). This has to be clarified.
Introduction
The introduction should be expanded to include findings on aboveground plant parts. It is insufficient to state that other studies have had a greater emphasis on aboveground parts. The conditions of the previously reported experiments should be clearly stated shortly here and in a broader sense in the Discussion section.
Materials and Methods
The whole analysis of morphological traits should be described in a betted way not just stating that parameters were measured and analysed by a scanner (they were really analysed or just scanned and the files collected?). What kind of parameters were considered for example to get the features such as a root surface area? How the flat scan was interpreted in terms of full surface and volume? I believe that some parameters were obtained in Win RHizo root image analysis system.
What “scanner’s tray added water” means here? Please explain
It was previously stated that root and shoot were packed in bag and dried at 65oC. How the Authors marked matching roots and shoots? The same with explanations concerning TNA, NUtE and NUpE in lines 143-148. Roots and shoots were pulled in and then the result were divided by the number of plants to receive biomass per plant?
Statistical analyses: what criteria for normality and homogeneity were considered?
Results
Paragraphs in results are grouped differently than those in materials and Methods
Does Fig. 1 represent wet weight of samples? I understand that biomass per plant comes from adding the mean value for roots and mean value for shoot?
Fig 2 clearly indicates that the only visible changes are for N2.4 sample. Is it really a biomass for plant or per root? Wet weight again? Again question how the Authors assigned the whole mass of plant? Does biomass mean that it was a wet weight ?
Was the mass of the plant calculated as the mass of root plus mass of shoot?
Figure 3 Effects of N addition on the enzyme activities in shoot and root of A. mongolicum. Remove bold letters from figure caption.
Figure 5 wrongly assigned as 4
Figure 6 (again wrongly assigned as 4) Remove the background from Fig 4. Simplify the drawing. Where are letters S and R (line 274). Remove unnecessary text from lines 279-281.
Discussion
N availability threshold was connected/ correlated with ???? parameters
Lines 314-316 – remarkable level of variation in root morphology. I would argue with this statement, as the differences in image 2 are only visible for sample N2.4. The rest is based on parameter analysis
Conclusions
Was really the plant response uni-modal or polynomial of 2 degree? Please explain
References: Make sure you follow the formatting of the references both in manuscript text and in References list. It should follow the guidelines of the journal Agronomy
Language
The language of the manuscript needs much revision. Please check the entire manuscript with particular attention to the abstract and the correct formulation of the purpose of the paper. Re-write parts of the text from lines 47-48, 66-69,292-293, 395-310, 316-317 etc.
Other remarks
- What “maniputlative experiments”(used twice) mean in line 48?
- What “ a controlled environmental experiments mean here (line 66) ? Why not just say pot experiments
- “Whole tillers of individuals” does it mean the whole plants or just tillers? (line 106)
- Separate envelopes ? (line 120) does it mean paper bags?
- Line 131 method of Asif et al. (2020) [18]
- Please use colors with more intensity and variation. Pale pink and pale green look the same when printed in a greyscale. This may really help some of the readers.
- remove bold letters from the figure captions
- what the “synthesized value” means in line 293
- What optimal nutrient level means in line 321?
Author Response
Dear reviewer
We thank you very much for giving us an opportunity to revise the manuscript MS. Your comments are valuable and very helpful for improving the quality of the MS. We have revised our manuscript carefully following your comments and provided specific responses to each of the comments, which we would like to submit for your kind consideration. Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
The manuscript has been revised to a very large extent. The authors have responded to most comments in a satisfactory manner. They have even changed the colors in the pictures so that in the black and white version you can see the differences better. I do not know if it is a matter of editing or software differences but in many places some words are merged. This should be checked before final approval.
