Exogenous Melatonin Improves Waterlogging Tolerance in Wheat through Promoting Antioxidant Enzymatic Activity and Carbon Assimilation
Round 1
Reviewer 1 Report
Interesting work with extensive scientific results. No major corrections about the scientific background.
Please check again some minor English language mistakes and the format of the text as well.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
According to the study of the manuscript with the number “
agronomy-1991481” and tittle “Exogenous melatonin improves grain development in waterlogged wheat by sustaining root growth and carbon assimilation”, the manuscript can be accepted in its original form. I have some suggestions to the author’s if they wish they can do the modification accordindly.
Ø It is suggested that the author should give the experimental design in tabular form, for the readers to understand it easily
Ø Figure 1 is the weather graph, my suggestion are if the authors themselves have prepared this graph via any scientific instrument then kindly mention the name of instrument and if they have sourced it from somewhere they should mention the particular sourse.
Ø Under Material Methods section (line no. 145), why authors have done sampling fpr Photosynthesis SPAD chlorophyll and Gas exchange traits at only three DDA (i.e 7, 14, 21 )and not done at 28 DDA. However, for growth parameters Sampling was done at 4 Different DDA (i.e 7, 14, 21, 28)
Ø The authors have repeatedly given the treatments details in all the given figure and tables, It is suggested that authors should give these details once in the treatment design and no need to mention it again and again in different figures and tables.
Conclusion of the reviewer report: The paper is well researched and presentation is excellent, graph are very well made, especially Figure 10 and 11 are outstanding in its presentation, and the way authors put their efforts in using the software is also very appreciable
Comments for author File: 
Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 3 Report
My comments are in the attached file.
Comments for author File: Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 4 Report
The subject of the MS "Exogenous melatonin improves grain development in waterlogged wheat by sustaining root growth and carbon assimilation' is interesting as melatonin has different functions in many aspects of plant growth and development. The most mentioned functions of melatonin are related to abiotic stresses such as drought, radiation, extreme temperature and chemical stress. Effects of melatonin to prevent waterlogging damages are much less studied. Grain development is an important process that determine grain yield and quality. Unfortunately, the MS has shortcomings that don't allow to recommend it for publication in its present form.
Major concerns:
Title: I suggest to edit the title as grain development is controlled by many factors and processes, but in the title those mentioned that were measured. Why root growth but not improved nutrient uptake or smth other, for example?
The interpretation of the results is not always correct. For instance "soil waterlogging inhibited root growth by increasing MDA and O2 production rates". MDA and O2 content do not inhibit growth themselve.
Two wheat cultivars were used, but which of them is more sensitive/tolerant to waterlogging was not mentioned (lines 104-105).
English language needs to be improved. Avoid such phases as "to protect yield from injury', 'roots also modulated ... enzymes'
It is not clear on figures where those 7 days when plants were waterlogged. Where they waterlogged during first 7 days on the figures? Then x-axis shows days after waterlogging. If not, then explain, please.
Why similar changes occur in waterlogged and non-waterlogged plants in respect to root gerowth inhibition (fig. 2), SOD activity decrease ,POD activity increase (fig. 3), MDA and O2 content increase (fig. 4). It is not clear why control (non-WL) plants demonstrate indicators of stress? Under normal conditions there should be no steady accumulation of ROS (lines 477-478).
Some figures have no SE bars, therefore it is not clear if the differences are significant or not. Often the differences are less than 5% and I doubt their significance. For instance, it seems that MT treatment had no effect on chl content (SPAD) (fig. 6a). As SPAD is a measure or relative chl content, it is not correct to compare values in %.
In the discussion I recomment to indicate what new results were obtained in this research. In many sentences you write about your results, but in the end put a reference to other work, where the same results were reported.
There is a repetition of results description in the discussion.
The conclusion is needed in the end.
Minor concerns:
Numbers throughout the MS can be rounded, for instance 18% instead of 17.94%. Hundreds in this case have no biological significance.
Line 59 - "plants wilter their leaves' - better 'leaves wilted'
Line 97: pH is not contained in soil samples. It is a property of soil samples.
Line 124 and throughout the text: Why do you use the word 'stem" instead of "plant"
Line 134: Please, provide the reference for the method used.
References 32-37 do not refer to the methods used, but to other research pepers, where the same methods were used. Please, provide proper references.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
Accept in present form
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 4 Report
The MS has been siginificantly improved, but there are still two points are to be improved.
1) line 168: SPAD-502 is a chlorophyll meter, therefore you measured relative chlorophyll content in SPAD units, not just SPAD values. I insist that values in SPAD units can not be campared in percentage as they are relative values.
2) Fig 7 - y-axis: Relative chloropyll content, SPAD units. Corresponding changes in the figure legend are required.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
