Effects of Exogenous Brassinolide Application at the Silking Stage on Nutrient Accumulation, Translocation and Remobilization of Waxy Maize under Post-Silking Heat Stress
Round 1
Reviewer 1 Report
Comments for author File: 
Comments.pdf
Author Response
The paper details the effect of a brassinosteroid application on heat stressed maize. All the necessary physiological parameters measured to give a good indication of the effect of the treatment. However, I have a problem with the replication – there were only three plants per cultivar per treatment (line 148) which is not sufficient. I would also have preferred to see at least two concentrations of BR used and perhaps more than one application. There are also important details missing from the methods. I have listed specific comments below.
Response: Each treatments including 50 plants. And three plants were selected to analysis the parameters. Other plants were selected to analysis the other parameters for different purpose.
INTRODUCTION
Line 37: what do you mean by “the greatest production”?
Response: The great production means than the yield of the maize was the greatest among the cereal crops (wheat, rice, maize, etc.).
Lines 63-64: what do you mean by this sentence?
Response: This sentence means that the HT on grain yield and starch quality was widely reported.
Line 84: write the genus name in full and should be italics
Response: The full name (Leymus chinensis) was added as in italics.
MATERIALS AND METHODS
Line 99: provide the co-ordinates of the experimental farm
Response: The co-ordinates was added as suggested.
Lines 104-110: Many details are missing from the methods so that they experiment is not reproducible – i) there is no mention of how the controls – were these sprayed with a surfactant minus BR etc; ii) how much time (in days) were the plants in the field, time in days between treatment and harvest etc; iii) what was the watering regime?
Response: i) the controls were sprayed with 100 ml water; ii) the plants were sown on March 15 and harvested at 40 days after pollination. iii) the water regimes were controlled by the weighing methods with the relative soil moisture was about 75% during plant growth.
Line 148: I am concerned about the replication – was the entire experiment conducted using 12 plants (3 plants x 4 treatments)? It is normal to combine a number of plants (at least 5 plants) to form a single replicate.
Response: Each treatments including 50 pots, with three plants at silking stage and maturity with similar phenotypes were selected and determined.
Line 150: no mention is made of how the correlation was calculated (Fig 4)
Response: The correlation was calculated by Microsoft Excel 2010.
RESULTS
Line 151: delete “and discussion” from the heading
Response: Delete as suggested.
The figured need to be improved – what does the abbreviation “CK” stand for; Figs. 2 and 3 need an X-axis title; Fig. 4 legend needs more detail
Response: The abbreviation of CK and BR was added in the figures 1-3, due to the different treatments (AT+CK, AT+BR, HT+CK, and HT+BR) was presented in the figures, the automated formed X-axis in figures 2-3 was not present in the X-axis title. The legend of Figure 4 present the correlation of grain yield (Y-axis title) with the post-silking DM (N, P, K) accumulation and pre-silking translocation, and the legends were improved following the suggests.
LANGUAGE
The language needs to be improved. I have listed a few examples where the text needs revision but there are too many mistakes to list them all.
Response: The language was improved as best as we can after revised the MS following the reviewer’s comments.
Line18: change to “..waxy maize exposed to high temperature (HT) stress during grain filling”
Response: Revised as suggested.
Line 20: delete “The results indicated that” and write as “BR application mitigated the…”
Response: Revised as suggested.
Line 29: correct to “was more obvious in the heat-tolerant hybrid”
Response: Revised as suggested.
Line 33: correct to “severely reducing crop productivity”
Response: Revised as suggested.
Line 40: correct to “higher”
Response: Revised as suggested.
Line 43: correct to “in the growing season”
Response: Revised as suggested.
Line 48: correct to “crops”
Response: Revised as suggested.
Line 59: do not start a sentence with the authors name as this is not concise – cite the authors at the end of the sentence
Response: Revised as suggested.
Line 61: correct to “did not affect”
Response: Revised as suggested.
Line 68: correct to “Plant growth regulator application is one of..”
Response: Revised as suggested.
Line 70: delete “very important”
Response: Revised as suggested.
Line 76: delete “Moreover”
Response: Deleted as suggested.
Line 90: do not write in the first person – delete “we” and rewrite sentence
Response: Revised as suggested.
Line 268: what do the abbreviations TAP, TRP and CTP stand for – write in full the first time they are used.
Response: The full name of TAP, TRP and CTP was first presented in the section of material and method (Lines 134-135, 137, and 140-141).
Correct the numerous typographical mistakes:
Remove the hyphen from many words – line 16, 18, 22, 37, 49, 53, 57, 65, 70, 84, 115, 134 and elsewhere in the manuscript (too numerous to list)
Response: The hyphens in the MS mainly due to the auto type setting of system. And those hyphens were checked and revised.
Reviewer 2 Report
The manuscript is well written and the observation made is quite good. The authors mainly focused on the accumulation, translocation and distribution of dry matter and nutrients (N,P, and K) upon treated with BR at silking stage and heat treatment at post-silking stage. The results and discussion are well written however, there are certain concern-
Line no. 326-328- the present study indicates that post-silking DM and K remobilization were unaffected and P was increased in both hybrids, is it during HT(high temperature) or AT (Ambient temperature)?
338-339- correct the sentences ‘ the observation demonstrated increase’
In the conclusion section, line no. 348-349- is not clear. Are the authors trying to state ‘grain yield was significantly decreased under HT on YN7 but not in JKN2000? However, under HT, BR application improved the grain yield in JKN2000 but not in YN7’.
Line 326-327- what may be the reason that that P was increased post-silking? The discussion part need to be strengthened.
There are many dashes between the words for eg. Line no. 260 ‘decreased’, line no. 225, ‘application’. Please correct.
Author Response
The manuscript is well written and the observation made is quite good. The authors mainly focused on the accumulation, translocation and distribution of dry matter and nutrients (N,P, and K) upon treated with BR at silking stage and heat treatment at post-silking stage. The results and discussion are well written however, there are certain concern-
Line no. 326-328- the present study indicates that post-silking DM and K remobilization were unaffected and P was increased in both hybrids, is it during HT(high temperature) or AT (Ambient temperature)?
Response: the sentence was revised as “Under HT condition, the post‒silking DM accumulation were unaffected in both hybrids, the N and K accumulation were unaffected and decreased by BR application in YN7 and JKN2000, whereas P accumulation was increased by exogenous BR application both hybrids.”, based on the data in table 1.
338-339- correct the sentences ‘ the observation demonstrated increase’
Response: The sentence was replaced by “The increased post‒silking DM and nutrient accumulation is vital to provide the photoassimilate for grain formation and development”
In the conclusion section, line no. 348-349- is not clear. Are the authors trying to state ‘grain yield was significantly decreased under HT on YN7 but not in JKN2000? However, under HT, BR application improved the grain yield in JKN2000 but not in YN7’.
Response: Yes. The sentence was replaced by “The grain yield was decreased by HT in YN7 and unaffected in JKN2000 regardless of the BR application. However, BR application improved the grain yield in in JKN2000 but not in YN7”
Line 326-327- what may be the reason that that P was increased post-silking? The discussion part need to be strengthened.
Response: The increased P accumulation may be due to the PGRs promote the plant growth and nutrient uptake, and the reference was added.
There are many dashes between the words for eg. Line no. 260 ‘decreased’, line no. 225, ‘application’. Please correct.
Response: The dashes may be caused the auto type setting of the word. And those may be revised during the latter retyping.
Reviewer 3 Report
The work presented for review describes the current issue of crop yielding under heat stress, which is more and more common due to the climate changes. The work concerns an economically important plant - maize, grown in regions particularly exposed to heat stress. The work contains interesting results pointing to the positive role of exogenous brasinosteroid application on waxy maize productivity. The authors used the latest literature in the paper, about 80% of the literature is from the last 5 years, which increases the scientific value of the work. However, I have some comments regarding figures and edition especially.
1) under the figures and tables you need to explain the abbreviation "CK", but I think it is better to use the abbreviation "C", because CK is associated with cytokinins and can be confusing, especially in tables 1-3, where the description of the column says "hormone"
2) the results presented in the first part of tables 1 and 3 could be presented in the form of graphs, it would definitely facilitate the interpretation of the results
3) subsection 3.7 requires more comment, also it is not known whether the given results refer to one hybrid or is it the generally observed trend for both hybrids
4) lines 298-300: the sentence is too strong, and the results obtained in the work are not sufficient to say this, but it can be speculated, so instead of "results indicated" it is better to write "results may indicate"
5) lines 311-312: please add that the results refer to maize, because the previous sentence is about rice and it is misleading
6) lines 57-66: abbreviation of element names should be standardized and appear in parentheses when the full name is first used; there is no explanation for K, of course it is obvious, but if the Authors decided on such style, it should apply to all elements
7) line 320: the abbreviation MDA should be explained
8) there are many words in the text separated by a hyphen, the ones I found are listed below, but the Authors should read the text carefully and correct it
Lines: 16, 18, 37, 49, 53, 65, 70, 84, 103, 119, 124, 126, 134, 166, 187, 197, 199, 201, 260, 268, 278, 286, 311, 317, 343, 363, 365
9) line 346: please delete dot in front of the word conclusion
Author Response
The work presented for review describes the current issue of crop yielding under heat stress, which is more and more common due to the climate changes. The work concerns an economically important plant - maize, grown in regions particularly exposed to heat stress. The work contains interesting results pointing to the positive role of exogenous brasinosteroid application on waxy maize productivity. The authors used the latest literature in the paper, about 80% of the literature is from the last 5 years, which increases the scientific value of the work. However, I have some comments regarding figures and edition especially.
1) under the figures and tables you need to explain the abbreviation "CK", but I think it is better to use the abbreviation "C", because CK is associated with cytokinins and can be confusing, especially in tables 1-3, where the description of the column says "hormone"
Response: In all the figures and tables, the explanation (CK, control, plants sprayed with 100 ml water; BR, brassinolide, plants sprayed with 100 ml 0.25 mg/L BR) of abbreviations of CK and BR was added in the notes, which can eliminate the misunderstand of abbreviations.
2) the results presented in the first part of tables 1 and 3 could be presented in the form of graphs, it would definitely facilitate the interpretation of the results
Response: The tables 1 and 3 were replaced by figures 3 and 4, respectively.
3) subsection 3.7 requires more comment, also it is not known whether the given results refer to one hybrid or is it the generally observed trend for both hybrids
Response: the correlation was based on the both hybrids, and result is the generally observed trend for both hybrids.
4) lines 298-300: the sentence is too strong, and the results obtained in the work are not sufficient to say this, but it can be speculated, so instead of "results indicated" it is better to write "results may indicate"
Response: Revised as suggested.
5) lines 311-312: please add that the results refer to maize, because the previous sentence is about rice and it is misleading
Response: Revised as suggested.
6) lines 57-66: abbreviation of element names should be standardized and appear in parentheses when the full name is first used; there is no explanation for K, of course it is obvious, but if the Authors decided on such style, it should apply to all elements
Response: The full name of K was added following the suggests.
7) line 320: the abbreviation MDA should be explained
Response: The MDA was replaced by its full name (malondialdehyde) as it only occurred once in the MS.
8) there are many words in the text separated by a hyphen, the ones I found are listed below, but the Authors should read the text carefully and correct it
Lines: 16, 18, 37, 49, 53, 65, 70, 84, 103, 119, 124, 126, 134, 166, 187, 197, 199, 201, 260, 268, 278, 286, 311, 317, 343, 363, 365
Response: the hyphen was due to the layout designer of the Journal, and those hyphens were checked after revised the MS.
9) line 346: please delete dot in front of the word conclusion
Response: Delete as suggested.
Reviewer 4 Report
Brassinosteroids (BRs) are a group of plant steroid hormone that are crucial for plant development, nutrient accumulation, and resistance to stress conditions. BR-related genes in crops of interest may be identified and its expression could be manipulated to simultaneously increase plant productivity and performance under adverse conditions. However, manipulating the expression of BR-regulated genes by mutation or overexpression often causes pleiotropic phenotypes that may negatively affect crops productivity. Thus, exogenous application of BRs could be a good option to overcome some types of stresses without adversely affect the whole plant grow. It has been described that BR application helps to alleviate stress in plants. But evaluating the beneficial effects of exogenous application of BRs requires further knowledge of how BR signaling operates in different crops, environments, and developmental contexts.
In the present work, authors test if BR application at the silking‒stage can improve the heat tolerance of maize during grain filling. To do that, they analyze the accumulation, translocation and remobilization of dry matter and nutrients (nitrogen, phosphorus, and potassium) of a heat-tolerant (JKN2000) and heat-sensitive (YN7) maize varieties submitted to high temperature.
The conclusion that authors presented: “BR application alleviated the negative effects of HT mainly due to the increased post-silking accumulation and remobilization of DM and N, and the alleviation was more obviously in heat‒tolerant hybrid” is supported by the detailed data presented, and this data is properly discussed by the authors.
One minor correction that a mention below should be adressed and clarified.
In figure 1,2 and 3 authors use CK as control but they don’t mention in figure legend what is CK. It is water, water with tween 20 or something else? This control treatment should also be described in material and methods section.
Author Response
Brassinosteroids (BRs) are a group of plant steroid hormone that are crucial for plant development, nutrient accumulation, and resistance to stress conditions. BR-related genes in crops of interest may be identified and its expression could be manipulated to simultaneously increase plant productivity and performance under adverse conditions. However, manipulating the expression of BR-regulated genes by mutation or overexpression often causes pleiotropic phenotypes that may negatively affect crops productivity. Thus, exogenous application of BRs could be a good option to overcome some types of stresses without adversely affect the whole plant grow. It has been described that BR application helps to alleviate stress in plants. But evaluating the beneficial effects of exogenous application of BRs requires further knowledge of how BR signaling operates in different crops, environments, and developmental contexts.
In the present work, authors test if BR application at the silking‒stage can improve the heat tolerance of maize during grain filling. To do that, they analyze the accumulation, translocation and remobilization of dry matter and nutrients (nitrogen, phosphorus, and potassium) of a heat-tolerant (JKN2000) and heat-sensitive (YN7) maize varieties submitted to high temperature.
The conclusion that authors presented: “BR application alleviated the negative effects of HT mainly due to the increased post-silking accumulation and remobilization of DM and N, and the alleviation was more obviously in heat‒tolerant hybrid” is supported by the detailed data presented, and this data is properly discussed by the authors.
One minor correction that a mention below should be adressed and clarified.
In figure 1,2 and 3 authors use CK as control but they don’t mention in figure legend what is CK. It is water, water with tween 20 or something else? This control treatment should also be described in material and methods section.
Response: The control treatment was described detailly in material and methods section. And CK in figures and tables were explained in note of figures and table.
