Efficient Physiological and Nutrient Use Efficiency Responses of Maize Leaves to Drought Stress under Different Field Nitrogen Conditions
Round 1
Reviewer 1 Report
The manuscript is written correctly and has all the elements necessary for this type of scientific work. The individual chapters of this study have been named correctly, which proves the author’s good orientation in the subject of interest. At the same time, this work arrangement properly introduces the reader to the subject. The content of the work corresponds to the topic specified in the title. I think that the layout of the work and the language in which it has been written is correct, although the authors did not avoid minor language and stylistic errors.
There is no research hypothesis about the purposefulness of undertaking such a research problem.
What mineral fertilizers were used in field tests (NPK), exact characteristics. What was the microbiological activity of the fertilizer tested?
What cotton cultivars were used in the study, characteristics?
Please correct the literature list in the manuscript.
Final conclusions
In the form presented, the work brings a lot of new information. It does not have to be completely rewritten and corrected. In conclusion, it should be stated that the work in the presented scope is interesting and suitable for publishing after taking into account comments of the Reviewer.
Author Response
Dear Editors and Reviewers,
Thank you very much for your advice and comments are relates to our manuscript. Your comments are very useful indeed toward the improvement of this draft. We have made the corresponding revisions according to the editors and reviewer’s comments. The English of the manuscript has also been further improved. The modifications made in the manuscript are marked in revised file. Our point-by-point responses to the comments of reviewers are included below as inserts marked in blue.
Thank you very much for considering our manuscript for publication in Agronomy. I am indeed grateful for your time, and look forward to hearing from you soon!
Best wishes,
Dr. Youliang Ye
Henan Agricultural University, Zhengzhou, 450002, China.
E-mail: [email protected]
----------------------------------------
Assistant Editor Comments:
It has been reviewed by experts in the field and we request that you make major revisions before it is processed further. Please revise the manuscript according to the reviewers' comments and upload the revised file within 10 days.
Response (R): Thank you very much for providing us with an opportunity to revise this paper. Two reviewers put forward many good proposals on revision. The paper has important significance for showing the responses of maize leaves to drought stress under different field N fertilizer application rates, and revealing the reason for leaf rolling under higher N fertilizer conditions. Different from previous drought simulation experiments of hydroponics and potting, this study was carried out under the field conditions. The viewpoints proposed are helpful to guide farmers in dry years or areas to apply N fertilizer rationally.
Comments and Suggestions for Authors:
Reviewer #1:
- The manuscript is written correctly and has all the elements necessary for this type of scientific work. The individual chapters of this study have been named correctly, which proves the author’s good orientation in the subject of interest. At the same time, this work arrangement properly introduces the reader to the subject. The content of the work corresponds to the topic specified in the title. I think that the layout of the work and the language in which it has been written is correct, although the authors did not avoid minor language and stylistic errors.
R: Thank you for your valuable time to help us review the manuscript. We appreciate your approval of our manuscript’s opinion, some language and stylistic errors in our manuscript would be reduced with the continuous modification and improvement.
- There is no research hypothesis about the purposefulness of undertaking such a research problem.
R: We have supplemented a research hypothesis in the section of ‘Introduction’, thank you for your suggestion. (R65-70 in the revision)
- What mineral fertilizers were used in field tests (NPK), exact characteristics.
R: Urea, calcium superphosphate and potassium chloride were used in field tests, we directly describe the fertilizer source of NPK in the section of ‘Materials and Methods’. (R105 in the revision)
- What was the microbiological activity of the fertilizer tested?
R: In this study, we only used chemical fertilizers, and did not use organic or microbial fertilizers, therefore, no microbial activity was tested.
- What cotton cultivars were used in the study, characteristics? Please correct the literature list in the manuscript.
R: We used these two cultivars Keyu 188 and Denghai 605 in our study, and added their characteristics in the section of ‘Materials and Methods’, thank you. (R95-96 in the revision)
Final conclusions
- In the form presented, the work brings a lot of new information. It does not have to be completely rewritten and corrected. In conclusion, it should be stated that the work in the presented scope is interesting and suitable for publishing after taking into account comments of the Reviewer.
R: Thank you for your approval, we will carefully modify to improve the quality of our manuscript according to your and other reviewers' suggestions.
Reviewer #2:
- P1 R38 'drought stress' not 'stress drought'.
R: Thank you very much for providing us with an opportunity to revise this paper. I could feel your professionalism in the process of modifying this manuscript. We have changed 'drought stress' to 'stress drought'. (R37 in the revision)
- P2 R54 'its presence' not ' it presence'.
R: You are right, we revised ‘it presence’ to ‘its presence’ (R59 in the revision).
- P2 R79 'used' rather than 'employed', incorrect use of word.
R: We carefully compared the usage of ‘use’, ‘employ’ and ‘utilize’, and thought that the word ‘use’ was correct. (R93 in the revision)
- P2 R83 and R87 what is a hm-2? Please define at the first use of unit.
R: Ok, we have supplemented the definition at the first use of unit (R98 in the revision).
- P2 R85 please include commas between 'randomized, complete, split-split-plot block design'.
R: Yes, the commas has been added, and this sentence became easier to understand (R100 in the revision).
- P2 R87 is this elemental N or fertiliser content rates? Please define clearly.
R: Here is elemental N, not fertiliser N, we have defined it, thank you for your suggestion (R102-103 in the revision).
- P3 R117 change 'grain yield' to simply 'yield' as you mention 'corn grain' in the following few words.
R: We have changed ‘grain yield’ to ‘yield’ in revised manuscript (R152 in the revision).
- P3 R117 change 'corn grains' to 'corn grain' (singular vs plural) (it is implied that there is more than one corn grain in the preceding 'yield').
R: We have changed 'corn grains' to 'corn grain' (R152 in the revision), thank you.
- P3 R123 and 124 is the ';' really necessary?
R: We have checked the formulas in other references and few authors added ';', so we deleted it as your suggestion. (R in the revision)
- P3 R123 and 124 include a space between 'applied' and 'rate' in the formulas.
R: Yes, added a space now (R167 in the revision), thank you for your careful review.
- P3 R125 change 'corn grains' to 'corn grain'.
R: We have changed 'corn grains' to 'corn grain' and ‘Grain yield’ to ‘Yield’. (R169 in the revision)
- P4 R137 at no point in the methods do you mention the use of drone photography for assessments, please include a small introduction to this technology in the methods.
R: We have supplemented the use of drone photography for assessments in the section of ‘Materials and Methods’, please see the R110-R116 in revised paper.
- P4 R139 Leaf rolling was observed but at no point in the methods do you indicate the observation or measurement technique. Please refer to briefly in section 2.3.
R: We have supplemented the observation method in the section of ‘Materials and Methods’, thank you for your reminder.
Ten ear leaves from each plot were selected in the morning (10:00–11:30 am). The leaf curl ratio was calculated from the leaf width with natural curling divided by its extended. In the present study, leaf curling was defined as the curl ratio below 0.8. (R126-128 in the revision)
- P5 R150 Please include a summary of the treatments in the text.
R: Sorry, I can not understand your suggestion. Please point out our deficiencies again, thank you. (R193 in the revision)
- P5 R152 Please outline what the symbols '**' refer to.
R: We have added the explanation of the symbols ‘*’, ‘**’ and ‘ns’, thank you for your kindly reminder. (R202 in the revision)
- P6 R156 Please re-write sentence " The soil water consumption rate was .... in the first 10 days without water, in the dry year.
R: Yes, your revised sentence is more suitable for what I wanted to describe, and do it as your suggestion. (R204-205 in the revision)
- P6 R157 Can you mark significant differences on the graphic? and refer to the graphic in the text when describing the results.
R: The Std Error bars can be added in the graphic, but looks messy, so we used the LSD0.05 vertical bars in this graphic and described the significant differences in the text, thank you for your suggestion. (R221 in the revision)
- P6 R165, this sentence needs checking 'The maize leaves appeared the curl up' should be' The maize leaves appeared to curl up'.
R: You are right, we revised it as your suggestion, but now we deleted this sentence.
- P6 R165 Not sure what figure 4 has to do with curling or unfurling, please remove reference to figure 4. Include this reference after the following paragraph.
R: Yes, you are right, we removed this sentence, and include this reference after the following paragraph. (R226 in the revision)
- P6 R168 I think this sentence should read ...However, in the drought stress year, the RWC of maize leaves ....
R: Yes, you said what I wanted to describe, and revised it as your suggestion. (R226-228 in the revision)
- P6 R169 This sentence does not read well, please outline the subject of the sentence first and then include the comparison statement. i.e. There was a reduction in RWC of 35.4% and 26.5% for the drought stress treatments compared to a non-drought stressed plot. Also what does the maximum refer to? Do you mean the maximum reduction? You have 5 treatments so you should indicate what 'maximum ' refers to across 5 treatments.
R: Yes, we missed some important information, and the maximum reduction refer to the difference value between drought and non-drought at N360 treatments, we have revised this sentence. (R228-229 in the revision)
- P7 R180 Remove 'The' and 'was' at beginning of sentence. This whole sentence need more detail, what do the % relate to? What different water conditions? please refer to your treatments - drought and non-drought. You don’t need 'were' in front of 'increased'. For example: Leaf Pn decreased by up to 90.7% in the drought treatment and 89.4% in the non-drought treatment with increasing N fertiliser rates, where the difference in leaf Pn between the treatments increased as N fertiliser rates increased.
R: Thank you for your patient guidance, ‘The’ and ‘was’ removed. And, this sentence revised as your suggestion ‘Compared with the non-drought stress plots, leaf Pn decreased by 25.8% - 90.7% in KY188 and 15.2% - 89.4% in DH605 at drought condition, where the difference in leaf Pn between the treatments increased as N fertilizer rates increased.’, please review it. (R238-239 in the revision)
- P7 R181 If you use these ranges please include spaces between '25.8% - 90.7%' and '15.2% - 89.4%'.
R: Yes, you are right, and we do. (R239 in the revision)
- P7 R190 change 'grain yields' to 'grain yield'.
R: Changed. (R in the revision)
- P7 R190 Change 'they' to 'yield'.
R: We have changed 'they' to 'yield' (R275 in the revision).
- P7 R198 Figure 6 Why do you present main effects when there is a significant interaction? Also if you use a regression (need to text linear and non-linear) for each variety and treatment you can show the relationships more different.
R: Yes, you are right, we deleted the main effects analysis in all Figures and Tables in our revised manuscript. Please review them in the revision, thank you. (R283 in the revision)
- P8 R206 N utilisation (as shown by NAE, NPFP and NHI) decreased with higher N application rates during the different rainfall years.
R: The sentence you modified was easy to understand for us, so do it as your suggestion. (R314 in the revision)
- P8 R209 remove 'was' before 'decreased' same for P8 R210.
R: They were both removed. (R316-317 in the revision)
- P8 R211 remove the word 'basically' (not very specific for scientific writing)
R: Ok, I admit it is colloquial, so we removed it as your suggestion. (R319 in the revision)
- P9 R226 Change 'where evaporation loss is dominant' to 'where evaporation loss is the more dominant of the two'.
R: We have changed this sentence as your commented. (R351 in the revision)
- P9 R226 Change 'Further' to 'Furthermore'; remove 'is' before 'increased' and change 'increased' to 'increases'.
R: All of them changed as your suggestion, thank you. (R351 in the revision)
- P9 R227 This sentence is very long, please consider breaking it up.
R: The sentence ‘The application of N fertilizer can expand the leaf canopies of plants, which act to shade the soil surface, which not only reduces the evaporation of moisture from the soil, but also exacerbates water consumption for plant transpiration’ was broken up to two parts ‘The application of N fertilizer can expand the leaf canopies of plants, which act to shade the soil surface. Although closed canopy reduces the evaporation of moisture from the soil, it exacerbates water consumption for plant transpiration’. (R352-353 in the revision)
- P9 R230 remove 'was'; remove reference to figure and outline what the reversed trend was in words. *Figure 1 and 2 should come before figure 3 in the manuscript as well.
R: We removed ‘was’; removed the reference to Figure and described the trend in words. (R356 in the revision)
Yes, the Figure 1 and 2 should come before Figure 3, we have reordered these Figures.
- P9 R232 again you refer to leaf curling but do not include the variable in your method.
R: Yes, we have supplemented the method on judgement of leaf curling in the section of ‘Materials and Methods’, thank you for your reminder. (R126-128 in the revision)
- P9 R235 Which studies? please reference, this sentence needs some work. You are also relating leaf rolling to N treatments but you have not told me what you measured or why it was measured. Now you have introduced a new variable 'time of leaf-rolling'?
R: We re-added the correct reference and reworked this sentence (R359-360 in the revision). We supplemented the evaluation method for leaf curling in the section of ‘Materials and Methods’.
Yes, the higher N rates the earlier the leaf curling occurred in the field, e.g. leaf curling at N360 occurred 10 days no water supply, while leaf curling at N120 occurred 15 days, but we lack data and photo to reflect this phenomenon. Here, we had to remove the part of ‘time of leaf-rolling’.
- P9 R238 This is obviously an important point but it is not clearly written, please reword also do you mean 'evapotranspiration' by the word 'dissipation' if so then use 'evapotranspiration' - did you not measure transpiration with photosynthesis on the LICOR - you probably have this data for comparison.
R: This sentence ‘This might have been the case as the application of N fertilizer increased water evapotranspiration, which surpassed the increased of N resistance to drought resistance for maize’ changed as ‘This might have been the case as the application of N fertilizer increased water evapotranspiration, which masked the N addition increased resistance to drought stress for maize’. (R361-364 in the revision)
We supplemented the data of transpiration rate in our revised paper, please review it, thank you.
- P10 R242 the word 'however' and 'was' are not required, please remove them, also what decreased under high N applications?
R: The sentence ‘Soil water deficits and high temperatures reduced the leaf RWC, which, however, was decreased under higher N application levels’ changed as ‘Soil water deficits and high temperatures reduced the leaf RWC, and the decrease in RWC was increased with increasing N fertilizer rate’. (R366 in the revision)
- P10 R243 You didn't measure leaf rolling so remove reference to it, also remove the word ' obviously', this sentence can be removed altogether. This paragraph needs to be reworked focus on the measured variables, the two varieties and the treatments.
R: Yes, we did not measure the degree of leaf curling accurately, it is a pity! But this phenomenon exists in our fields, now we can still see from the photos that the degree of leaf curling was increased with increasing N fertilizer rates. (R371-376 in the revision)
- P10 R255 Why what is the mechanical reason for this in the leaf?
R: Water loss reduced leaf turgor, further resulted in leaf curling. ‘Water loss in the leaf center likely contributed more to the degree of leaf rolling than did water loss at the leaf margin.’, it is the result of our data analysis, but we did not find the mechanical reason for this phenomenon from previous studies. We assumed that the mechanism by which water loss in the leaf center is more likely to cause leaf-curling, which may be similar to the mechanism of mimosa leaf closure after stimulation.
- P10 R256 remove the word 'sacrifice'. Maybe reword this because the subject of this sentence is leaf rolling and why it occurs from a physiology perspective. Make 'leaf rolling' as a symptom of water deficit the subject of the sentence.
R: Changed the word 'sacrifice' to ‘decrease’. (R375 in the revision)
This sentence has been rewritten as ‘Leaf water limitation induced the reduction of bulliform cell turgor, which are involved in rolling and unrolling leaves under drought conditions. Further, leaf curling decreases leaf transpiration, temperature and incident irradiance, which decrease the potential for photoinhibition, prolong physiological activity, and increase survival during drought’. (R373-376 in the revision)
- P10 R263 - 265 Did you measure ABA? Did you measure stomatal conductance? If not, you can only assume the process that occurred was this you cannot claim that it did occur with any certainty. Reword to reflect the likelihood of this occurring as a result of the imposed treatment conditions.
R: We did not measure it, and you are right, the process that occurred was I assumed, we lack direct evidences.
We revised this sentence as ‘Soil moisture deficits decreased the leaf RWC, which might trigger the de novo synthesis of abscisic acid (ABA) in the leaves, where the generation of ABA resulted a decline in stomatal conductance. Further, stomatal closure may contribute to the reduced Pn values. (R380-383 in the revision)
- P11 R272 please define MDA.
R: Ok, since MDA appeared only once in this paper, we used ‘malonaldehyde’ instead of ‘MDA’. (R390 in the revision)
- P11 R275 please remove 'was'.
R: Removed. (R393 in the revision)
- P11 R276 'Replace 'Further' with Furthermore', this sentence could be improved by using the subject matter at the beginning of the sentence. i.e. Furthermore, increased applications of N did not alleviate drought stress.
R: Your suggested sentence is more in line with what we wanted to express, and revised it as your commented. (R393-394 in the revision)
- P11 R276 Not sure what this means, please review.
R: We reworked this sentence as ‘The decrease of yield between drought and non-drought stress increased with increasing N rates. Furthermore, increased applications of N did not alleviation drought stress in the present study’. (R392-393 in the revision)
- P11 R279 replace 'filed' with 'field', please review this sentence.
R: A spelling mistake, replace it as your suggestion (R397 in the revision).
- P11 R288 If there is a clear association of these genes in the variety then you could associate this argument, otherwise it is only likely and should be worded as such. If you have more on the benefits of these varieties then this could be described in the introduction.
R: The scientist found that drought stress up-regulated the glutamine synthetase and asparagine synthetase genes in maize, and these two genes facilitate N nutrition transport from vegetative organs to productive organs in general. Currently, a clear association of these genes with drought and N remobilization in maize. (R661 in the revision)
- P11 R292 Your conclusion should indicate how there was an inverse relationship between N and water where water consumption was greater at lower N rates IN THE ABSENCE OF WATER (drought). The relationship between water and nitrogen in its limitations on plant growth and productivity should be clearly defined.
R: Conclusion revised as ‘In the well-water condition, the application of N fertilizer enhanced plant water transpiration and net photosynthetic rate, further increasing corn yield. In the absence of water, soil water consumption was greater at lower N rates, the application of N fertilizer decreased the leaf RWC, which led to leaf curling and the further reduction of photosynthesis. Thus, the recommended quantity of N fertilizer for plants under drought stress should be appropriately reduced to align with local conditions. (R665-668 in the revision)
Thank you again for your kindly comments and suggestions.
Author Response File: 
Author Response.docx
Reviewer 2 Report
P1 R38 'drought stress' not 'stress drought'
P2 R54 'its presence' not 'it presence'
P2 R79 'used' rather than 'employed', incorrect use of word
P2 R83 and R87 what is a hm-2? Please define at the first use of unit.
P2 R85 please include commas between 'randomized, complete, split-split-plot block design'
P2 R87 is this elemental N or fertiliser content rates? Please define clearly.
P3 R117 change 'grain yield' to simply 'yield' as you mention 'corn grain' in the following few words
P3 R117 change 'corn grains' to 'corn grain' (singular vs plural)(it is implied that there is more than one corn grain in the preceding 'yield')
P3 R123 and 124 is the ';' really necessary?
P3 R123 and 124 include a space between 'applied' and 'rate' in the formulas
P3 R125 change 'corn grains' to 'corn grain'
P4 R137 at no point in the methods do you mention the use of drone photography for assessments, please include a small introduction to this technology in the methods
P4 R139 Leaf rolling was observed but at no point in the methods do you indicate the observation or measurement technique. Please refer to briefly in section 2.3.
P5 R150 Please include a summary of the treatments in the text
P5 R152 Please outline what the symbols '**' refer to.
P6 R156 Please re-write sentence " The soil water consumption rate was .... in the first 10 days without water, in the dry year.
P6 R157 Can you mark significant differences on the graphic? and refer to the graphic in the text when describing the results
P6 R165, this sentence needs checking ' The maize leaves appeared the curl up' should be ' The maize leaves appeared to curl up'
P6 R165 Not sure what figure 4 has to do with curling or unfurling, please remove reference to figure 4. Include this reference after the following paragraph.
P6 R168 I think this sentence should read ...However, in the dought stress year, the RWC of maize leaves ....
P6 R169 This sentence does not read well, please outline the subject of the sentence first and then include the comparison statement.i.e. There was a reduction in RWC of 35.4% and 26.5% for the drought stress treatments compared to a non-drought stressed plot. Also what doe sthe maximum refer to? Do you mean the maximum reduction? You have 5 treatments so you should indicate what 'maximum ' refers to across 5 treatments.
P7 R180 Remove 'The' and 'was' at beginning of sentence. This whole sentence need more detail, what do the % relate to? What different water conditions? please refer to your treatments - drought and non-drought. You dont need 'were' in front of 'increased'.
For example : Leaf Pn decreased by up to 90.7% in the drought treatment and 89.4% in the non-drought treatment with increasing N fertiliser rates, where the difference in leaf Pn between the treatments increased as N fertiliser rates increased.
P7 R181 If you use these ranges please include spaces between '25.8% - 90.7%' and '15.2% - 89.4%'.
P7 R190 change 'grain yields' to 'grain yield'
P7 R190 Change 'they' to 'yield'
P7 R198 Figure 6 Why do you present main effects when there is a significant interaction? Also if you use a regression (need to text linear and non-linear) for each variety and treatment you can show the relationships more dofferent.
P8 R206 N utilisation (as shown by NAE, NPFP and NHI) decreased with higher N application rates during the different rainfall years.
P8 R209 remove 'was' before 'decreased' same for P8 R210.
P8 R211 remove the word 'basically' (not very specific for scientific writing)
P9 R226 Change 'where evaporation loss is dominant' to 'where evaporation loss is the more dominant of the two'
P9 R226 Change 'Further' to 'Furthermore'; remove 'is' before 'increased' and change 'increased' to 'increases'
P9 R227 This sentence is very long, please consider breasking it up.
P9 R230 remove 'was'; remove reference to figure and outline what the reversed trend was in words.
*Figure 1 and 2 should come before figure 3 in the manuscript as well
P9 R232 again you refer to leaf curling but do not include the variable in your method
P9 R235 Which studies ? please reference, this sentence needs some work
You are also relating leaf rolling to N treatments but you have not told me what you measured or why it was measured. Now you have introduced a new variable 'time of leaf-rolling'?
P9 R238 This is obviously an important point but it is not clearly written, please reword also do you mean 'evaoptranspiration' by the word 'dissipation' if so then use 'evapotranspiration' - did you not measure transpiration with photosynthesis on the LICOR - you probably have this data for comparison
P10 R242 the word 'however' and 'was' are not required, please remove them, also what decreased under high N applications?
P10 R243 You didn't measure leaf rolling so remove reference to it, also remove the word ' obviously', this sentence can be removed altogether.
This paragraph needs to be reworked focus on the measured variables, the two varieties and the treatments.
P10 R255 Why what is the mechanical reason for this in the leaf?
P10 R256 remove the word 'sacrifice'. Maybe reword this because the subject of this sentence is leaf rolling and why it occurs from a physiology perspective. Make 'leaf rolling' as a symptom of water deficit the subject of the sentence.
P10 R263 - 265 Did you measure ABA? Did you measure stomatal conductance? If not you can only assume the process that occurred was this you cannot claim that it did occur with any certainty. Reword to reflect the likelihood of this occurring as a result of the imposed treatment conditions.
P11 R272 please define MDA
P11 R275 please remove 'was'
P11 R276 'Replace 'Further ' with Furthermore', this sentence oculd be improved by using the subject matter at the beginning of the sentence.i.e.Furthermore, increased applications of N did not alleviate drought stress.
P11 R276 Not sure what this means, please review
P11 R279 replace 'filed' with 'field', please review this sentence
P11 R288 If there is a clear association of these genes in the variety then you could associate this argument, otherwise it is only likely and should be worded as such. If you have more on the benefits of these varieties then this could be described in the introduction.
P11 R292 Your conclusion should indicate how there was an inverse relationship between N and water where water consumption was greater at lower N rates IN THE ABSENCE OF WATER (drought). The relationship between water and nitrogen in its limitiations on plant growth and productivity should be clearly defined.
Author Response
Dear Editors and Reviewers,
Thank you very much for your advice and comments are relates to our manuscript. Your comments are very useful indeed toward the improvement of this draft. We have made the corresponding revisions according to the editors and reviewer’s comments. The English of the manuscript has also been further improved. The modifications made in the manuscript are marked in revised file. Our point-by-point responses to the comments of reviewers are included below as inserts marked in blue.
Thank you very much for considering our manuscript for publication in Agronomy. I am indeed grateful for your time, and look forward to hearing from you soon!
Best wishes,
Dr. Youliang Ye
Henan Agricultural University, Zhengzhou, 450002, China.
E-mail: [email protected]
----------------------------------------
Assistant Editor Comments:
It has been reviewed by experts in the field and we request that you make major revisions before it is processed further. Please revise the manuscript according to the reviewers' comments and upload the revised file within 10 days.
Response (R): Thank you very much for providing us with an opportunity to revise this paper. Two reviewers put forward many good proposals on revision. The paper has important significance for showing the responses of maize leaves to drought stress under different field N fertilizer application rates, and revealing the reason for leaf rolling under higher N fertilizer conditions. Different from previous drought simulation experiments of hydroponics and potting, this study was carried out under the field conditions. The viewpoints proposed are helpful to guide farmers in dry years or areas to apply N fertilizer rationally.
Comments and Suggestions for Authors:
Reviewer #1:
- The manuscript is written correctly and has all the elements necessary for this type of scientific work. The individual chapters of this study have been named correctly, which proves the author’s good orientation in the subject of interest. At the same time, this work arrangement properly introduces the reader to the subject. The content of the work corresponds to the topic specified in the title. I think that the layout of the work and the language in which it has been written is correct, although the authors did not avoid minor language and stylistic errors.
R: Thank you for your valuable time to help us review the manuscript. We appreciate your approval of our manuscript’s opinion, some language and stylistic errors in our manuscript would be reduced with the continuous modification and improvement.
- There is no research hypothesis about the purposefulness of undertaking such a research problem.
R: We have supplemented a research hypothesis in the section of ‘Introduction’, thank you for your suggestion. (R65-70 in the revision)
- What mineral fertilizers were used in field tests (NPK), exact characteristics.
R: Urea, calcium superphosphate and potassium chloride were used in field tests, we directly describe the fertilizer source of NPK in the section of ‘Materials and Methods’. (R105 in the revision)
- What was the microbiological activity of the fertilizer tested?
R: In this study, we only used chemical fertilizers, and did not use organic or microbial fertilizers, therefore, no microbial activity was tested.
- What cotton cultivars were used in the study, characteristics? Please correct the literature list in the manuscript.
R: We used these two cultivars Keyu 188 and Denghai 605 in our study, and added their characteristics in the section of ‘Materials and Methods’, thank you. (R95-96 in the revision)
Final conclusions
- In the form presented, the work brings a lot of new information. It does not have to be completely rewritten and corrected. In conclusion, it should be stated that the work in the presented scope is interesting and suitable for publishing after taking into account comments of the Reviewer.
R: Thank you for your approval, we will carefully modify to improve the quality of our manuscript according to your and other reviewers' suggestions.
Reviewer #2:
- P1 R38 'drought stress' not 'stress drought'.
R: Thank you very much for providing us with an opportunity to revise this paper. I could feel your professionalism in the process of modifying this manuscript. We have changed 'drought stress' to 'stress drought'. (R37 in the revision)
- P2 R54 'its presence' not ' it presence'.
R: You are right, we revised ‘it presence’ to ‘its presence’ (R59 in the revision).
- P2 R79 'used' rather than 'employed', incorrect use of word.
R: We carefully compared the usage of ‘use’, ‘employ’ and ‘utilize’, and thought that the word ‘use’ was correct. (R93 in the revision)
- P2 R83 and R87 what is a hm-2? Please define at the first use of unit.
R: Ok, we have supplemented the definition at the first use of unit (R98 in the revision).
- P2 R85 please include commas between 'randomized, complete, split-split-plot block design'.
R: Yes, the commas has been added, and this sentence became easier to understand (R100 in the revision).
- P2 R87 is this elemental N or fertiliser content rates? Please define clearly.
R: Here is elemental N, not fertiliser N, we have defined it, thank you for your suggestion (R102-103 in the revision).
- P3 R117 change 'grain yield' to simply 'yield' as you mention 'corn grain' in the following few words.
R: We have changed ‘grain yield’ to ‘yield’ in revised manuscript (R152 in the revision).
- P3 R117 change 'corn grains' to 'corn grain' (singular vs plural) (it is implied that there is more than one corn grain in the preceding 'yield').
R: We have changed 'corn grains' to 'corn grain' (R152 in the revision), thank you.
- P3 R123 and 124 is the ';' really necessary?
R: We have checked the formulas in other references and few authors added ';', so we deleted it as your suggestion. (R in the revision)
- P3 R123 and 124 include a space between 'applied' and 'rate' in the formulas.
R: Yes, added a space now (R167 in the revision), thank you for your careful review.
- P3 R125 change 'corn grains' to 'corn grain'.
R: We have changed 'corn grains' to 'corn grain' and ‘Grain yield’ to ‘Yield’. (R169 in the revision)
- P4 R137 at no point in the methods do you mention the use of drone photography for assessments, please include a small introduction to this technology in the methods.
R: We have supplemented the use of drone photography for assessments in the section of ‘Materials and Methods’, please see the R110-R116 in revised paper.
- P4 R139 Leaf rolling was observed but at no point in the methods do you indicate the observation or measurement technique. Please refer to briefly in section 2.3.
R: We have supplemented the observation method in the section of ‘Materials and Methods’, thank you for your reminder.
Ten ear leaves from each plot were selected in the morning (10:00–11:30 am). The leaf curl ratio was calculated from the leaf width with natural curling divided by its extended. In the present study, leaf curling was defined as the curl ratio below 0.8. (R126-128 in the revision)
- P5 R150 Please include a summary of the treatments in the text.
R: Sorry, I can not understand your suggestion. Please point out our deficiencies again, thank you. (R193 in the revision)
- P5 R152 Please outline what the symbols '**' refer to.
R: We have added the explanation of the symbols ‘*’, ‘**’ and ‘ns’, thank you for your kindly reminder. (R202 in the revision)
- P6 R156 Please re-write sentence " The soil water consumption rate was .... in the first 10 days without water, in the dry year.
R: Yes, your revised sentence is more suitable for what I wanted to describe, and do it as your suggestion. (R204-205 in the revision)
- P6 R157 Can you mark significant differences on the graphic? and refer to the graphic in the text when describing the results.
R: The Std Error bars can be added in the graphic, but looks messy, so we used the LSD0.05 vertical bars in this graphic and described the significant differences in the text, thank you for your suggestion. (R221 in the revision)
- P6 R165, this sentence needs checking 'The maize leaves appeared the curl up' should be' The maize leaves appeared to curl up'.
R: You are right, we revised it as your suggestion, but now we deleted this sentence.
- P6 R165 Not sure what figure 4 has to do with curling or unfurling, please remove reference to figure 4. Include this reference after the following paragraph.
R: Yes, you are right, we removed this sentence, and include this reference after the following paragraph. (R226 in the revision)
- P6 R168 I think this sentence should read ...However, in the drought stress year, the RWC of maize leaves ....
R: Yes, you said what I wanted to describe, and revised it as your suggestion. (R226-228 in the revision)
- P6 R169 This sentence does not read well, please outline the subject of the sentence first and then include the comparison statement. i.e. There was a reduction in RWC of 35.4% and 26.5% for the drought stress treatments compared to a non-drought stressed plot. Also what does the maximum refer to? Do you mean the maximum reduction? You have 5 treatments so you should indicate what 'maximum ' refers to across 5 treatments.
R: Yes, we missed some important information, and the maximum reduction refer to the difference value between drought and non-drought at N360 treatments, we have revised this sentence. (R228-229 in the revision)
- P7 R180 Remove 'The' and 'was' at beginning of sentence. This whole sentence need more detail, what do the % relate to? What different water conditions? please refer to your treatments - drought and non-drought. You don’t need 'were' in front of 'increased'. For example: Leaf Pn decreased by up to 90.7% in the drought treatment and 89.4% in the non-drought treatment with increasing N fertiliser rates, where the difference in leaf Pn between the treatments increased as N fertiliser rates increased.
R: Thank you for your patient guidance, ‘The’ and ‘was’ removed. And, this sentence revised as your suggestion ‘Compared with the non-drought stress plots, leaf Pn decreased by 25.8% - 90.7% in KY188 and 15.2% - 89.4% in DH605 at drought condition, where the difference in leaf Pn between the treatments increased as N fertilizer rates increased.’, please review it. (R238-239 in the revision)
- P7 R181 If you use these ranges please include spaces between '25.8% - 90.7%' and '15.2% - 89.4%'.
R: Yes, you are right, and we do. (R239 in the revision)
- P7 R190 change 'grain yields' to 'grain yield'.
R: Changed. (R in the revision)
- P7 R190 Change 'they' to 'yield'.
R: We have changed 'they' to 'yield' (R275 in the revision).
- P7 R198 Figure 6 Why do you present main effects when there is a significant interaction? Also if you use a regression (need to text linear and non-linear) for each variety and treatment you can show the relationships more different.
R: Yes, you are right, we deleted the main effects analysis in all Figures and Tables in our revised manuscript. Please review them in the revision, thank you. (R283 in the revision)
- P8 R206 N utilisation (as shown by NAE, NPFP and NHI) decreased with higher N application rates during the different rainfall years.
R: The sentence you modified was easy to understand for us, so do it as your suggestion. (R314 in the revision)
- P8 R209 remove 'was' before 'decreased' same for P8 R210.
R: They were both removed. (R316-317 in the revision)
- P8 R211 remove the word 'basically' (not very specific for scientific writing)
R: Ok, I admit it is colloquial, so we removed it as your suggestion. (R319 in the revision)
- P9 R226 Change 'where evaporation loss is dominant' to 'where evaporation loss is the more dominant of the two'.
R: We have changed this sentence as your commented. (R351 in the revision)
- P9 R226 Change 'Further' to 'Furthermore'; remove 'is' before 'increased' and change 'increased' to 'increases'.
R: All of them changed as your suggestion, thank you. (R351 in the revision)
- P9 R227 This sentence is very long, please consider breaking it up.
R: The sentence ‘The application of N fertilizer can expand the leaf canopies of plants, which act to shade the soil surface, which not only reduces the evaporation of moisture from the soil, but also exacerbates water consumption for plant transpiration’ was broken up to two parts ‘The application of N fertilizer can expand the leaf canopies of plants, which act to shade the soil surface. Although closed canopy reduces the evaporation of moisture from the soil, it exacerbates water consumption for plant transpiration’. (R352-353 in the revision)
- P9 R230 remove 'was'; remove reference to figure and outline what the reversed trend was in words. *Figure 1 and 2 should come before figure 3 in the manuscript as well.
R: We removed ‘was’; removed the reference to Figure and described the trend in words. (R356 in the revision)
Yes, the Figure 1 and 2 should come before Figure 3, we have reordered these Figures.
- P9 R232 again you refer to leaf curling but do not include the variable in your method.
R: Yes, we have supplemented the method on judgement of leaf curling in the section of ‘Materials and Methods’, thank you for your reminder. (R126-128 in the revision)
- P9 R235 Which studies? please reference, this sentence needs some work. You are also relating leaf rolling to N treatments but you have not told me what you measured or why it was measured. Now you have introduced a new variable 'time of leaf-rolling'?
R: We re-added the correct reference and reworked this sentence (R359-360 in the revision). We supplemented the evaluation method for leaf curling in the section of ‘Materials and Methods’.
Yes, the higher N rates the earlier the leaf curling occurred in the field, e.g. leaf curling at N360 occurred 10 days no water supply, while leaf curling at N120 occurred 15 days, but we lack data and photo to reflect this phenomenon. Here, we had to remove the part of ‘time of leaf-rolling’.
- P9 R238 This is obviously an important point but it is not clearly written, please reword also do you mean 'evapotranspiration' by the word 'dissipation' if so then use 'evapotranspiration' - did you not measure transpiration with photosynthesis on the LICOR - you probably have this data for comparison.
R: This sentence ‘This might have been the case as the application of N fertilizer increased water evapotranspiration, which surpassed the increased of N resistance to drought resistance for maize’ changed as ‘This might have been the case as the application of N fertilizer increased water evapotranspiration, which masked the N addition increased resistance to drought stress for maize’. (R361-364 in the revision)
We supplemented the data of transpiration rate in our revised paper, please review it, thank you.
- P10 R242 the word 'however' and 'was' are not required, please remove them, also what decreased under high N applications?
R: The sentence ‘Soil water deficits and high temperatures reduced the leaf RWC, which, however, was decreased under higher N application levels’ changed as ‘Soil water deficits and high temperatures reduced the leaf RWC, and the decrease in RWC was increased with increasing N fertilizer rate’. (R366 in the revision)
- P10 R243 You didn't measure leaf rolling so remove reference to it, also remove the word ' obviously', this sentence can be removed altogether. This paragraph needs to be reworked focus on the measured variables, the two varieties and the treatments.
R: Yes, we did not measure the degree of leaf curling accurately, it is a pity! But this phenomenon exists in our fields, now we can still see from the photos that the degree of leaf curling was increased with increasing N fertilizer rates. (R371-376 in the revision)
- P10 R255 Why what is the mechanical reason for this in the leaf?
R: Water loss reduced leaf turgor, further resulted in leaf curling. ‘Water loss in the leaf center likely contributed more to the degree of leaf rolling than did water loss at the leaf margin.’, it is the result of our data analysis, but we did not find the mechanical reason for this phenomenon from previous studies. We assumed that the mechanism by which water loss in the leaf center is more likely to cause leaf-curling, which may be similar to the mechanism of mimosa leaf closure after stimulation.
- P10 R256 remove the word 'sacrifice'. Maybe reword this because the subject of this sentence is leaf rolling and why it occurs from a physiology perspective. Make 'leaf rolling' as a symptom of water deficit the subject of the sentence.
R: Changed the word 'sacrifice' to ‘decrease’. (R375 in the revision)
This sentence has been rewritten as ‘Leaf water limitation induced the reduction of bulliform cell turgor, which are involved in rolling and unrolling leaves under drought conditions. Further, leaf curling decreases leaf transpiration, temperature and incident irradiance, which decrease the potential for photoinhibition, prolong physiological activity, and increase survival during drought’. (R373-376 in the revision)
- P10 R263 - 265 Did you measure ABA? Did you measure stomatal conductance? If not, you can only assume the process that occurred was this you cannot claim that it did occur with any certainty. Reword to reflect the likelihood of this occurring as a result of the imposed treatment conditions.
R: We did not measure it, and you are right, the process that occurred was I assumed, we lack direct evidences.
We revised this sentence as ‘Soil moisture deficits decreased the leaf RWC, which might trigger the de novo synthesis of abscisic acid (ABA) in the leaves, where the generation of ABA resulted a decline in stomatal conductance. Further, stomatal closure may contribute to the reduced Pn values. (R380-383 in the revision)
- P11 R272 please define MDA.
R: Ok, since MDA appeared only once in this paper, we used ‘malonaldehyde’ instead of ‘MDA’. (R390 in the revision)
- P11 R275 please remove 'was'.
R: Removed. (R393 in the revision)
- P11 R276 'Replace 'Further' with Furthermore', this sentence could be improved by using the subject matter at the beginning of the sentence. i.e. Furthermore, increased applications of N did not alleviate drought stress.
R: Your suggested sentence is more in line with what we wanted to express, and revised it as your commented. (R393-394 in the revision)
- P11 R276 Not sure what this means, please review.
R: We reworked this sentence as ‘The decrease of yield between drought and non-drought stress increased with increasing N rates. Furthermore, increased applications of N did not alleviation drought stress in the present study’. (R392-393 in the revision)
- P11 R279 replace 'filed' with 'field', please review this sentence.
R: A spelling mistake, replace it as your suggestion (R397 in the revision).
- P11 R288 If there is a clear association of these genes in the variety then you could associate this argument, otherwise it is only likely and should be worded as such. If you have more on the benefits of these varieties then this could be described in the introduction.
R: The scientist found that drought stress up-regulated the glutamine synthetase and asparagine synthetase genes in maize, and these two genes facilitate N nutrition transport from vegetative organs to productive organs in general. Currently, a clear association of these genes with drought and N remobilization in maize. (R661 in the revision)
- P11 R292 Your conclusion should indicate how there was an inverse relationship between N and water where water consumption was greater at lower N rates IN THE ABSENCE OF WATER (drought). The relationship between water and nitrogen in its limitations on plant growth and productivity should be clearly defined.
R: Conclusion revised as ‘In the well-water condition, the application of N fertilizer enhanced plant water transpiration and net photosynthetic rate, further increasing corn yield. In the absence of water, soil water consumption was greater at lower N rates, the application of N fertilizer decreased the leaf RWC, which led to leaf curling and the further reduction of photosynthesis. Thus, the recommended quantity of N fertilizer for plants under drought stress should be appropriately reduced to align with local conditions. (R665-668 in the revision)
Thank you again for your kindly comments and suggestions.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
Row 25 and 26 does not need the word ‘state’ repeated twice please remove the second one
Row 62 This sentence would read better if it said ‘the addition of N’ not ‘the N addition’.
Row 62 Replace ‘proved’ with ‘shown’, in science we cannot prove anything, we hypothesize and show results exist to within certain confidence limits.
Row 64 Could still need some work ‘ Hence, we wondered if we could improve the drought resistance of maize by regulating the amount of N fertilizer in field, determine what is the optimal amount of N fertilizer under drought stress conditions.’ I don’t understand what the last section of this sentence is saying please exclude or simplify - ‘and if the N fertilizer inputs would be more in contrast to non-drought condition’.
Row 65 Replace ‘condition’ with ‘conditions’
Row 93, 97, 100, 235, 239, 284, Not sure why hectare is abbreviated as (hm-2) should just be (ha-1)
Row 135 Please remove the words ‘and employed’
Row 188 please replace the word ‘showed’ with ‘shown’
Row 219 Replace ‘at’ with ‘in’ and ‘condition ‘ with ‘conditions’
Row 287 Remove ‘string’ and replace ‘stomatal’ with ‘stomata’
Row 291 Include ‘to’ between higher N and enter.
Row 293 and 294 The sentence would read better if it said ….’earlier, which masked the increased resistance to drought stree with additional N for maize’. Please check this interpretation.
Row 296 remove ‘was’ before ‘increased’
Row 297 replace ‘rate’ with ‘rates’
Row 329 Replace ‘alleviation’ with ‘alleviate’
Author Response
Dear Assistant Editor and Reviewer,
Thank you very much for your comments/suggestions on our manuscript again. Your recognition is the driving force for us to move forward. We have made the changes according to the comments of assistant editor and the worthy reviewer. The modifications made in the manuscript are marked in revised file. Our point-by-point responses to the comments of the reviewers’ are included below as inserts highlighted in blue.
Thank you very much for considering our manuscript for publication in Agronomy. I am indeed grateful for your time, and look forward to hearing from you soon!
Best wishes,
Dr. Youliang Ye
Henan Agricultural University, Zhengzhou, 450002, China.
E-mail: [email protected]
----------------------------------------
Assistant Editor Comments:
It has been reviewed by experts in the field and we request that you make minor revisions before it is processed further. Please revise the manuscript according to the reviewers' comments and upload the revised file within 2 days.
Response (R): Thank you very much for providing us with an opportunity to revise this paper. The reviewer put forward many good proposals on revision.
Comments and Suggestions for Authors:
Reviewer #2:
- Row 25 and 26 does not need the word ‘state’ repeated twice please remove the second one
R: We have removed the repeated word ‘state’. (R24 in the revision)
- Row 62 This sentence would read better if it said ‘the addition of N’ not ‘the N addition’.
R: Yes, you are right, and do it. (R61 in the revision)
- Row 62 Replace ‘proved’ with ‘shown’, in science we cannot prove anything, we hypothesize and show results exist to within certain confidence limits.
R: We are convinced by your explanation, thank you for your guidance. (R61 in the revision)
- Row 64 Could still need some work ‘Hence, we wondered if we could improve the drought resistance of maize by regulating the amount of N fertilizer in field, determine what is the optimal amount of N fertilizer under drought stress conditions.’ I don’t understand what the last section of this sentence is saying please exclude or simplify - ‘and if the N fertilizer inputs would be more in contrast to non-drought condition’.
R: Re-worked this sentence as your suggestions, and the last section is not important, then excluding this section. (R64-65 in the revision)
- Row 65 Replace ‘condition’ with ‘conditions’
R: We have removed this sentence. (R65 in the revision)
- Row 93, 97, 100, 235, 239, 284, Not sure why hectare is abbreviated as (hm-2) should just be (ha-1)
R: ‘hm-2’ used more than ‘ha-1’ in China. We used ‘ha-1’ in our revised manuscript now, thank you for your suggestion.
- Row 135 Please remove the words ‘and employed’
R: This has been done. (R129 in the revision)
- Row 188 please replace the word ‘showed’ with ‘shown’
R: Changed ‘showed’ to ‘shown’. (R176 in the revision)
- Row 219 Replace ‘at’ with ‘in’ and ‘condition ‘with ‘conditions’
R: Replaced the two words. (R200 in the revision)
- Row 287 Remove ‘strong’ and replace ‘stomatal’ with ‘stomata’
R: Remove the word ‘strong’ and replaced ‘stomatal’ with ‘stomata’. (R254-255 in the revision)
- Row 291 Include ‘to’ between higher N and enter.
R: Yes, added it. (R258 in the revision)
- Row 293 and 294 The sentence would read better if it said ….’earlier, which masked the increased resistance to drought stress with additional N for maize’. Please check this interpretation.
R: We checked this sentence, and your suggested sentence was better than mine, so revised it as your comment, thank you. (R259 in the revision)
- Row 296 remove ‘was’ before ‘increased’
R: Removed as suggestion. (R261 in the revision)
- Row 297 replace ‘rate’ with ‘rates’
R: We have replaced ‘rate’ with ‘rates’, thank you. (R262 in the revision)
- Row 329 Replace ‘alleviation’ with ‘alleviate’
R: We have replaced it as your suggestion, thank you. (R289 in the revision)
Thank you again for your kindly comments and suggestions.
Author Response File: Author Response.docx
