Use of a Biostimulant to Mitigate Salt Stress in Maize Plants
Round 1
Reviewer 1 Report
Paper: “Use of Biostimulant to mitigate salt stress in maize plants” by D’Amato R. and Del Buono D.
By reading the Introduction I immediately realized that most citations are not appropriate. Some examples: citation 8 is not the most appropriate citation for giving a general overview about the adverse effects of salt stress on plant physiology. Several reviews have been published by Rana Munns about this topic. Reference 9 concerns the environmental impact of two biostimulants, and nothing about the salt impact on enzyme activity, as stated. Reference 10 is about a bioassay developed by Rana Munns to detect a growth inhibition in xylem sap, and for sure it is not the right article to be cited about the detrimental effect of salt on cellular sodium accumulation. Citation 11 is about a natural bee-honey based biostimulant effect on antioxidant defence, and not about reduction in biomass production induced by salt, as stated. The same for citation 7, which is not appropriate for explaining the role of ROS. Since the article contains 62 citations, I did not read any further.
The experimental design is by far too simple. A preliminary screening experiment with different salt concentrations and a time course analysis of growth parameters should be carried out. The correct timing for biostimulant supply should be evaluated in preliminary experiments. Moreover, it is not clear the biostimulant concentration used. Authors state that the concentration corresponds to the dosage recommended by the manufacturer, but it should be considered that the experimental model (hydroponic growth) is greatly different from the field-grown design. Thus, a preliminary experiment with different doses of biostimulant should have been done.
Author Response
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Author Response.pdf
Reviewer 2 Report
- Line 98: What is the composition of the Half Hoagland solution?
- The Hoagland hydroponic solution contains 1.21 ppm Na and 0.14 to 0.65 ppm Cl (https://en.wikipedia.org/wiki/Hoagland_solution)
- Line 110: Provide the reference for the method that has been used to determine the Na+ and K+ concentrations in shoot maize.
- Line 128: Provide the reference for the method that has been used to sample methanolic extract.
Author Response
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Reviewer 3 Report
- The introduction should be rewritten and please add the causes of salinity.
- The introduction section, speaks about the effects of salts on plants, what about those plants that need salts to grow.
- Authors didn’t clarify if biostimulants are natural substances or chemicals.
- . What are the other factors that can affect plant production other than the salinity.
- A table can be used to describe the advantages and disadvantages of chemicals used to produce plant biostimulants, if found. Medicinal agreements/Ethical permission should be included in such studies.
- Uses of Megafol (Meg) and its chemical formulas should be described and if possible, the way of production.
- Type and analysis of the water used to irrigate the crop throughout the experiment would be added.
- Freeze-drying seems to be better in treating samples rather than heat-drying as the salt ratio could be changed. Metabolomics could be recommended for such sensitive analysis.
- The effect of different concentrations of Megafol (Meg) should be mentioned.
- Controlled samples of soils and their nutrients should be included for measuring the environmental impact.
- Total growth conditions including temperature, light uses, would be included.
- A comparative study should be mentioned using reference products.
- The author should highlight in more detail how Megafol (Meg) has a proper effect and please cite other research results, line 271.
- The author should discuss the decrease of the chlorophyll.
- In line 42 please enlist the disorders that are caused by high salts.
- In the method section, please explain the reason behind using these concentrations of solutions.
- In the section of “Na+ and K+ Concentrations in Shoot Maize” the high temperature can affect the metabolism of plant, please explain.
- In method section, please add the reference of the extraction of samples with methanol.
- In the result section, where is the equation that was used for calculation of the quantity of total phenolic compounds.
- Please give the reason for not mentioning the effects of salinity on the Maize leaves.
- Please prepare the graphical abstract
- Please add the list of abbreviation.
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
In the present manuscript, the effect of biostimulant application on alleviating salinity stress effects in maize plants was evaluated.
Revise the title and instead of maize plants indicate that maize seedlings were tested.
How many plants per replicate were used? Provide details about the cultivation system and the growing conditions.
Give details about the biostimulant product composition.
Provide dry matter content values for shoots and roots.
Divide the Discussion section is subparagraphs that correspond to the studied parameters in order to make the flow of reading easier.
The results should be discuss based on the composition of the applied biostimulant. As it is the discussion is descriptive and does not provide evidence about the possible mechanisms that are responsible for the observed effects.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Accept in present form
Reviewer 4 Report
The authors performed the suggested corrections. Therefore, I recommend the acceptance of the mansucript in its present form.
