Coordinating Postanthesis Carbon and Nitrogen Metabolism of Hybrid Rice through Different Irrigation and Nitrogen Regimes
, Yuanyuan Sun 2, Fengjun Yan 1, Yue Li 1, Yunxia Wu 1, Changchun Guo 1, Peng Ma 1, Guotao Yang 1, Zhiyuan Yang 1 and Jun Ma 1,*Round 1
Reviewer 1 Report
General comments: This is a well-designed study investigating irrigation and N-fertilization regimes on post-anthesis carbon and nitrogen metabolism of hybrid rice. The study was thorough and produced readily applicable results. Some sections, especially the Abstract and the Methods sections need a fair amount of editing for English language issues. I have done my best to correct and clarify here. Some of the Tables and Figures are missing elements or use incomplete terminology, so check the notes below for my suggestions. I have not checked the References for proper journal format, or to see that all references listed are cited and vice versa. I did notice, however, that most reference are numbered twice, which I assume was not intentional.
Overall: Check that your use of “postanthesis” and “post-anthesis” is consistent throughout the document. Either is acceptable.
Abstract: You refer to “13C and 15N” in the Abstract, and then switch to superscripted 13C and 15N in the rest of the paper. Be consistent.
Line 12: Replace “In order to” with “We sought to”
Line 15: “irrigation and nitrogen fertilization (W-N) regimes”
Line 18: “combined with the N fertilization regime”
Line 19: “for rice yield and NUE increase. This regime enhanced flag leaf photosynthesis rate…”
Line 24: the two stars after r=0.825 have no meaning in the Abstract. I would remove them here.
Line 27: “N fertilization regimes”
Line 30-31: Consider the following re-wording: “Yield formation in rice mainly depends on the degree of coordination of carbon and nitrogen (C-N) metabolism during the filling stage”
Line 31: “It has been shown that”
Line 32: comma after “flowering”
Line 46: “subject to feedback from”
Line 78: “Pot and field experiments were conducted on a research farm located…”
Line 80: “was sandy loam”
Line 96: “our earlier research”
Line 181-183: Suggest: “The temperature, relative humidity, rainfall, and cumulative hours of sunshine over the 2 years from full-heading to maturity stage (30 d after full heading) were provided by the Meteorological Observatory Station and averaged every 5 d.”
Line 183-189: Suggest: “With only once exception, there were no significant differences in climate parameter values across the different stages of rice postanthesis and between the two years of the study (Fig. 1). The exception was in 2015 when, 6-10 days after anthesis, a heavy rainfall of 102.9 mm occurred within a 12-h period (Fig. 1E); there was almost no impact on the deficit irrigation treatment W3 due to timely drainage of the plots. Characterization of the sampling environment at the main stages postanthesis in both years of the study is shown in Table 2.
Figure 1. Where are the error bars for 1E and 1F?
Table 2. The second parameter in the left-hand column should be “Photosynthetically Active Radiation.”
Line 201-204: Suggest: “Data analysis and graphing functions were performed using SAS 8.1 and SigmaPlot 12.0, respectively.”
Line 247: “WUE was more affected…”
Tables 4-9: The footnotes should read: “Values within a column followed by different letters are significantly different at…”
Line 395: “…the enzyme activities…”
Lines 446-447: “enzyme activities”
Line 450-455: Suggest: “This study also showed that when the amount of N application shifted to postpone reached 60% (N3 treatment), compared to W1, the inadequate irrigation (W2 and W3 treatments) caused a decrease in the enzyme activities of C-N metabolism of postanthesis flag leaves, a significant decrease in N accumulation, an increased retention of C assimilates in leaves and stems/sheaths, and a significant decrease in C assimilates in panicles, leading to a significant reduction in NAE and NPE.”
Line 489: “needs”
Line 510: “enzyme activities”
Line 521: “enzyme activities”
Line 553 and 554: “enzyme activities”
Author Response
Dear reviewer,
RE: Manuscript Agronomy-881833
We are pleased to submit our revised manuscript (Agronomy-881833) entitled “Coordinating Postanthesis Carbon and Nitrogen Metabolism of Hybrid Rice through Different Irrigation and Nitrogen Regimes”. We appreciate your constructive comments and suggestions. The manuscript has been modified based on your suggestions. We hope that the revision has sufficiently addressed the concerns and the manuscript is acceptable for publication. Please let me know if you have any questions.
Sincerely,
Dr. Yongjian Sun
Response to Reviewer 1 Comments
Point 1: Overall: Check that your use of “postanthesis” and “post-anthesis” is consistent throughout the document. Either is acceptable.
Response 1: According to the reviewer’s comment, the “post-anthesis” was changed to “postanthesis” in this paper.
Point 2: Abstract: You refer to “13C and 15N” in the Abstract, and then switch to superscripted 13C and 15N in the rest of the paper. Be consistent.
Response 2: According to the reviewer’s comment, the “13C and 15N” was switched to superscripted “13C and 15N” in the abstract.
Point 3: Line 12: Replace “In order to” with “We sought to”
Response 3: We have used “We sought to” instead of “In order to” in L12.
Point 4: Line 15: “irrigation and nitrogen fertilization (W-N) regimes”
Response 4: According to the reviewer’s comment, we added “fertilization” after “nitrogen” in L15.
Point 5: Line 18: “combined with the N fertilization regime”
Response 5: According to the reviewer’s comment, we added “fertilization” after “N” in L18.
Point 6: Line 19: “for rice yield and NUE increase. This regime enhanced flag leaf photosynthesis rate…”
Response 6: According to the reviewer’s comment, we added “This regime” after “increase” in L19.
Point 7: Line 24: the two stars after r=0.825 have no meaning in the abstract. I would remove them here.
Response 7: According to the reviewer’s suggestion, we deleted the two stars “**” after r=0.825 in Line 24.
Point 8: Line 27: “N fertilization regimes”
Response 8: According to the reviewer’s comment, we added “fertilization” after “N” in L27.
Point 9: Line 30-31: Consider the following re-wording: “Yield formation in rice mainly depends on the degree of coordination of carbon and nitrogen (C-N) metabolism during the filling stage”
Response 9: We accept reviewer’s advice to revise the first sentence of the paper “Yield formation in rice mainly depends on the degree of coordination of carbon and nitrogen (C-N) metabolism during the filling stage”
Point 10: Line 31: “It has been shown that”
Response 10: We have used “shown” instead of “proven” in L31.
Point 11: Line 32: comma after “flowering”
Response 11: We accept reviewer’s advice, add comma after “flowering” in L32.
Point 12: Line 46: “subject to feedback from”
Response 12: According to the reviewer’s comment, we deleted “the” after “subject to” in L46.
Point 13: Line 78: “Pot and field experiments were conducted on a research farm located…”
Response 13: We modified it in manuscript according to the reviewer’s suggestions in L78.
Point 14: Line 80: “was sandy loam”
Response 14: We accept reviewer’s advice, delete “of” after “was” in L80.
Point 15: Line 96: “our earlier research”
Response 15: According to the reviewer’s comment, the “our earlier researches” was changed to “our earlier research” in L96.
Point 16: Line 181-183: Suggest: “The temperature, relative humidity, rainfall, and cumulative hours of sunshine over the 2 years from full-heading to maturity stage (30 d after full heading) were provided by the Meteorological Observatory Station and averaged every 5 d.”
Response 16: We modified it in manuscript according to the reviewer’s suggestions in L181-183.
Point 17: Line 183-189: Suggest: “With only once exception, there were no significant differences in climate parameter values across the different stages of rice postanthesis and between the two years of the study (Fig. 1). The exception was in 2015 when, 6-10 days after anthesis, a heavy rainfall of 102.9 mm occurred within a 12-h period (Fig. 1E); there was almost no impact on the deficit irrigation treatment W3 due to timely drainage of the plots. Characterization of the sampling environment at the main stages postanthesis in both years of the study is shown in Table 2.
Response 17: We modified it in manuscript according to the reviewer’s suggestions in L183-189.
Point 18: Figure 1. Where are the error bars for 1E and 1F?
Response 18: Figure 1A, 1B, 1C, and 1D are the error bars of the mean within 5 days in each year, and Figure 1E and 1F represent rainfall accumulation and cumulative amount of sunshine hours within 5 days in each year, respectively. Therefore, there is no error bars for 1E and 1F.
Point 19: Table 2. The second parameter in the left-hand column should be “Photosynthetically Active Radiation.”
Response 19: According to the reviewer’s comment, we added “Photosynthetically” before “active radiation” in the second parameter in the left-hand column of Table 2.
Point 20: Line 201-204: Suggest: “Data analysis and graphing functions were performed using SAS 8.1 and SigmaPlot 12.0, respectively.”
Response 20: We modified it in manuscript according to the reviewer’s suggestions in L201-204.
Point 21: Line 247: “WUE was more affected…”
Response 21: According to the reviewer’s comment, we have used “WUE was” instead of “WUE were” in L247.
Point 22: Tables 4-9: The footnotes should read: “Values within a column followed by different letters are significantly different at…”
Response 22: According to the reviewer’s comment, we have used “within” instead of “with” in Tables 4-9.
Point 23: Line 395: “…the enzyme activities…”
Response 23: According to the reviewer’s comment, the “the enzymes activities” was changed to “the enzyme activities” in L395.
Point 24: Lines 446-447: “enzyme activities”
Response 24: According to the reviewer’s comment, the “enzymes activities” was changed to “enzyme activities” in L395.
Point 25: Line 450-455: Suggest: “This study also showed that when the amount of N application shifted to postpone reached 60% (N3 treatment), compared to W1, the inadequate irrigation (W2 and W3treatments) caused a decrease in the enzyme activities of C-N metabolism of postanthesis flag leaves, a significant decrease in N accumulation, an increased retention of C assimilates in leaves and stems/sheaths, and a significant decrease in C assimilates in panicles, leading to a significant reduction in NAE and NPE.”
Response 25: We modified it in manuscript according to the reviewer’s suggestions in L450-455.
Point 26: Line 489: “needs”
Response 26: According to the reviewer’s comment, the “need” was changed to “needs” in L489.
Point 27: Line 510: “enzyme activities”
Response 27: According to the reviewer’s comment, the “enzymes activities” was changed to “enzyme activities” in L510.
Point 28: Line 521: “enzyme activities”
Response 28: According to the reviewer’s comment, the “enzymes activities” was changed to “enzyme activities” in L521.
Point 29: Line 553 and 554: “enzyme activities”
Response 29: According to the reviewer’s comment, the “enzymes activities” was changed to “enzyme activities” in L553 and 554.
Point 30: “that most reference are numbered twice”.
Response 30: According to the reviewer’s comment, we deleted a number.
Reviewer 2 Report
Authors have done a great deal of work and have collected the data extensively. I think your concept is novel and unique and your paper present all the information about water and nitrogen requirement of rice plant. However your method of presentation, mainly your method section is very unclear. You extrapolate and assume in the result section and the information provided on the statistical strength for the manuscript is very weak. It is difficult to understand your experimental design and replicate your work. You should clearly define those details on the manuscript. I would incline rejected your paper and asked to resubmit it after extensive improvement but the data you have in your paper is really good. Therefore ask you to revise the manuscript to clearly explain the design, replication and treatment and resubmit it.
Following are some of the areas that require revision:
Line 85
What was the source of water and what were the water quality parameters?
Line 91
What does field well watered 1-2 cm water layer mean? This is under the section of pot experiment.
Line 100-101
Where was the fertilizer applied, what was the source of fertilizer and what about base fertilizer application time. The application process (where) of booting fertilizer application is also unclear. Elaborate those on the manuscript.
Line 102 onwards
The process of pulse labeling and feed of 13CO2 is very unclear. Your citation of method from lit 4 is not enough, please explain how 13 CO2 was generated, explain more about the construction of chamber, what four containers?, explain about the assimilation and more. Please elaborate this process and include the figure of your setup if possible. How was water circulated to cool the chamber?
Line 112 to line 124
This section should occur before the line 102. And there is no explanation of replications per treatments for pot experiments.
Line 120
N labelling process is not explained explain it.
Your experimental design both for pot experiment and field experiment is very unclear. Please include a separate section for experimental design in materials and method. You can also clearly explain the replication per treatment here. Also you can show all your treatment in this section.
Line 138
Include the calculation formula for MTNA, NGPE, NMPE, NAE, NRE and NPE as equations with appropriate citation.
Explain how WUE and NUE was determined and elaborate all the abbreviations at first occurrence.
Line 143
Which treatment, explain.
Section 2.2.4
What the co2, humidity and temperature at Pn measurement chamber?
Line 163
What was the irrigation treatment of those plants? W1, W2 or W3 or all ?
When and how many times pot experiment was done and when and how many times field experiment was done? Your method section is very unclear and need to be extensively improved. Also state what result was derived from field study and what was derived from field study somewhere in the method section or may be even in the objective part of introduction section.
Section 2.3
What was the design of experiment, what method did you use in SAS. Your data analysis contain all the details about the method of you data analysis.
Line 225
How could you statistically tell that the difference between W2 and W1 treatments was not significant, did you do the analysis on the average value on w2 and w1 treatments?
Line 246
Include your calculation procedure for water and nitrogen use efficiency in method section.
Line 273
Both Fig 2A, 2B and 2C do not have letters for difference in means. Include it if you found those were significant.
Also for the unit of photosynthesis rate is it mmol or mmol, if it is mmol it looks very high?
Line 306
Your wording implies like W2 treatment had 0.97 and 6.07 13C per plant. Replace ‘reached’ with ‘was’ in line 306
Section 3.5
You refer to transport from ………… to grains. How did you determine transport from stems or leaves to grains statistically?
Line 321
Do not generalize in result section. Do this for all.
You say at the maturity stage the difference in 12C assimilates in leaves between irrigation treatment was not signification. Well for W3 and N2 it is different. Do not generalize.
Line 329
Not for all right? For W1 and w3 (root and leaf) it actually was same or higher, do not extrapolate or generalize in result section.
Correct fonts for table 7 heading
Line 342
There is no word like extremely significant, just stating significant will work. Correct for all instances.
Line 347
How did you figure out the N transport statistically?
Line 374 to line 377
Very long sentence and unclear. Shorten it and improve clarity.
Line 547-548
Did you also do the analysis of different combination of N application technique? Was it different?
Author Response
Dear reviewer,
RE: Manuscript Agronomy-881833
We are pleased to submit our revised manuscript (Agronomy-881833) entitled “Coordinating Postanthesis Carbon and Nitrogen Metabolism of Hybrid Rice through Different Irrigation and Nitrogen Regimes”. We appreciate your constructive comments and suggestions. The manuscript has been modified based on your suggestions. We hope that the revision has sufficiently addressed the concerns and the manuscript is acceptable for publication. Please let me know if you have any questions.
Sincerely,
Dr. Yongjian Sun
Response to Reviewer 2 Comments
Point 1: Line 85: What was the source of water and what were the water quality parameters?
Response 1: According to the reviewer’s comment, we add the source of water and the water quality parameters in pot and field experiments, respectively. In pot experiments, we add “with tap water (public drinking water quality, pH 7.12, Nitrate-N 9.6 mg L-1, dissolved oxygen concentration 8.1 mg L-1)” in section 2.1.1. In field experiments, we add “irrigation water with underground water (pH 7.23, Nitrate-N 14.1 mg L-1, ammonium-N 0.45 mg L-1).”
Point 2: Line 91: What does field well watered 1-2 cm water layer mean? This is under the section of pot experiment.
Response 2: According to the reviewer’s suggestion, we restate the water management approach of W2 and W3. The “the field well watered 1-2 cm water layer” was changed to “re-watered with water layer 1-2 cm” in W2 treatment. The “the field well watered (yet with no flooded water accumulated in the field)” was changed to “re-watered with no water layer (soil water potential -5 kPa~0 kPa).” in W3 treatment.
Point 3:Line 100-101:Where was the fertilizer applied, what was the source of fertilizer and what about base fertilizer application time. The application process (where) of booting fertilizer application is also unclear. Elaborate those on the manuscript.
Response 3: According to the reviewer’s comment, “in pot experiments”, we add the source of 15N fertilize“Shanghai Research Institute of Chemical Industry”，“base fertilizer was applied 1 day before transplanting”. We have used “the booting fertilizer was split into equal applications at top 4th and 2nd leaf in the N1, N2, and N3 treatments.” instead of “the fertilizer applied at the booting stage was equally divided into two portions, which were respectively applied at top 4th and 2nd leaf in the N1, N2, and N3 treatments” in L100-101.
Point 4: Line 102 onwards: The process of pulse labeling and feed of 13CO2 is very unclear. Your citation of method from lit 4 is not enough, please explain how 13CO2 was generated, explain more about the construction of chamber, what four containers?, explain about the assimilation and more. Please elaborate this process and include the figure of your setup if possible. How was water circulated to cool the chamber?
Response 4: According to the reviewer’s comment, we add chemical reactions “2NaH13CO3+H2SO4 → Na2SO4+213CO2↑”, and further explain “2 mol L-1 H2SO4 was slowly injected with syringes through a dropper into four containers (uniform 13CO2 release) that were hung on the top of the chamber”, and add test setup picture of transparent plexiglass chambers and four containers in chamber (Figure 1) to further explain. Tap water was used to cool the plexiglass chambers. Please see the revised manuscript for details,thank you.
Figure 1. The transparent plexiglass chambers and four containers in chamber
Point 5: Line 112 to line 124: This section should occur before the line 102. And there is no explanation of replications per treatments for pot experiments.
Response 5: According to the reviewer’s suggestion, move the Line 112 to line 124 to the front of line 102, and we further explain “with 12 treatment combinations (three irrigation regimes and four N regimes). Each treatment had 40 pots (15 pots were labelled by applying 15N fertilizer, 25 pots without labelled were used for physiological indicator determination) as repetitions in a complete randomized block design.”, and further explain “Before flowering, 8 pots were selected form 15 pots with 15N labelling for each treatment as well as the N0 treatment feed 13CO2. After the isotope labelling at the full-heading stage, 4 pots were sampled immediately to analyze d13C and d15N values, and the other 4 pots were returned to the pot experimental location for further growth, at the maturity stage were sampled to analyze d13C and d15N values.”
Point 6: Line 120: N labelling process is not explained explain it. Your experimental design both for pot experiment and field experiment is very unclear. Please include a separate section for experimental design in materials and method. You can also clearly explain the replication per treatment here. Also you can show all your treatment in this section.
Response 6: According to the reviewer’s suggestion, in pot experiment, we further explain N labelling process“Each treatment had 40 pots (15 pots were labelled by applying 15N fertilizer, 25 pots without labelled were used for physiological indicator determination)…”, “Four N regimes in pot experiments including three different 15Nregimes (15N-labeled urea replace unlabelled urea, Shanghai Research Institute of Chemical Industry; abundance of 10.02%) were included, with the ratios for base, tillering, and booting fertilizer applied at the stage of 50:30:20, 30:30:40, and 30:10:60. No N application was also set as a control. These treatments were, respectively, named N1, N2, N3, and N0.” In field experiment, we further explain“The irrigation and N regimes with 3×4 factorial with a complete randomized block design for the field experiments….”, and add “Each treatment is repeated 3 times.”
Point 7: Line 138: Include the calculation formula for MTNA, NGPE, NMPE, NAE, NRE and NPE as equations with appropriate citation. Explain how WUE and NUE was determined and elaborate all the abbreviations at first occurrence.
Response 7: According to the reviewer’s suggestion, we add the calculation formula for MTNA, NGPE, NMPE, NAE, NRE and NPE as equations, and explain WUE and NUE was determined and elaborate all the abbreviations at first occurrence in section 2.2.1.
NAE, NPE and NRE were comprehensive indexes reflecting the NUE.
NGPE= grain yield / total N uptake
NMPE= total dry matter production/ total N uptake
NAE = (grain yield in N supply- grain yield in zero N supply)/ N supply rate
NRE = (total N uptake in N supply- total N uptake in zero N supply)/ N supply rate
NPE= NAE/NRE
WUE = grain yield/ irrigation water rate
Point 8: Line 143: Which treatment, explain.
Response 8: According to the reviewer’s comment, we have used “each W-N treatment combination” instead of “each treatment” in L143 and in this paper.
Point 9: Section 2.2.4: What the CO2, humidity and temperature at Pn measurement chamber?
Response 9: According to the reviewer’s comment, we further explain “Pn was measured at 400µmolmol-1 CO2, flow rate 0.5 L min-1, chamber relative humidity 70%-75%, and chamber temperature 30℃.”
Point 10: Line 163: What was the irrigation treatment of those plants? W1, W2 or W3 or all ? When and how many times pot experiment was done and when and how many times field experiment was done? Your method section is very unclear and need to be extensively improved. Also state what result was derived from field study and what was derived from field study somewhere in the method section or may be even in the objective part of introduction section.
Response 10: According to the reviewer’s comment, we further explain“8 pots were labeled with 13C and 15N and sampled for each W-N treatment combination at full-heading stage (4 pots) and at maturity stage (4 pots), respectively.”About pot and field experiment s times and method relevant supplementary explanation were listed in response 5, response 6, and response 7.
Point 11: Section 2.3: What was the design of experiment, what method did you use in SAS. Your data analysis contain all the details about the method of you data analysis.
Response 11: According to the reviewer’s comment, we further explain“The randomized complete block model was used included sources of variation due to replication, year, irrigation method, N application ratio, and year × irrigation method, year ×N application ratio, and irrigation method ×N application ratio. Means were tested by least significant difference (LSD) at the 0.05 level (LSD0.05). Correlation analysis deal with relationships among variables and find the correlation coefficients between a pair of variables in a dataset.”
Point 12: Line 225: How could you statistically tell that the difference between W2 and W1 treatments was not significant, did you do the analysis on the average value on w2 and w1 treatments?
Response 12: According to the reviewer’s comment, the results of ANOVA are supplemented in each irrigation method across all N application in table 4-table 8, and add note in table 4-table 8. “a Average indexes for each irrigation method across all N application and followed different letters are significantly different at P < 0.05.”
Point 13: Line 246: Include your calculation procedure for water and nitrogen use efficiency in method section.
Response 13: According to the reviewer’s suggestion, we add the calculation formula for water and nitrogen use efficiency in method section 2.2.1, which were listed in response 5.
Point 14:Line 273: Both Fig 2A, 2B and 2C do not have letters for difference in means. Include it if you found those were significant. Also for the unit of photosynthesis rate is it mmol or mmol, if it is mmol it looks very high?
Response 14: According to the reviewer’s suggestion, we replaced original Figure 2 and Figure 3 and add a significant letters. The unit of photosynthetic rate (A), RuBPcase (B) and SPS enzymes (C) activity was error in manuscript. We have used “µmol” instead of “mmol” in Figure 2. Thank you very much for your correction.
Please see the revised manuscript for details, thank you.
Point 15: Line 306: Your wording implies like W2 treatment had 0.97 and 6.07 13C per plant. Replace ‘reached’ with ‘was’ in line 306
Response 15: According to the reviewer’s comment, replace ‘reached’ with ‘was’ in line 306.
Point 16: Section 3.5: You refer to transport from ………… to grains. How did you determine transport from stems or leaves to grains statistically?
Response 16: According to the reviewer’s comment, we add the calculation formula and further explain “13C translocation was calculated as 13C accumulation in leaves or stems at full-heading stage minus 13C remaining in leaves or stems at maturity stage”
Point 17: Line 321:Do not generalize in result section. Do this for all. You say at the maturity stage the difference in 12C assimilates in leaves between irrigation treatment was not signification. Well for W3 and N2 it is different. Do not generalize.
Response 17: According to the reviewer’s comment, the results of ANOVA are supplemented in each irrigation method across all N application in table 4-table 8. Original meaning: A comparison between averages 13C assimilates for each irrigation method across all N application and we add“average of”front W2 treatment.
Point 18: Line 329: Not for all right? For W1 and w3 (root and leaf) it actually was same or higher, do not extrapolate or generalize in result section. Correct fonts for table 7 heading
Response 18: According to the reviewer’s comment, we replace “in stem and panicle” with “in various nutrient organs” in Line 329, and correct fonts for table 7 heading
Point 19: Line 342:There is no word like extremely significant, just stating significant will work. Correct for all instances.
Response 19: According to the reviewer’s comment, we deleted “extreme” word.
Point 20: Line 347:How did you figure out the N transport statistically?
Response 20: According to the reviewer’s comment, we add the calculation formula and further explain “15N translocation was calculated as 15N accumulation in leaves at full-heading stage minus 15N remaining in leaves at maturity stage”and“15N translocation was calculated as 15N accumulation in stems at full-heading stage minus 15N remaining in stems at maturity stage”
Point 21: Line 374 to line 377: Very long sentence and unclear. Shorten it and improve clarity.
Response 21: According to the reviewer’s suggestion, we rewrite sentence of Line 374 to line 377“After N fertilizer application for the same irrigation regime, the C/N ratios in vegetative organs showed increasing trends to different extents (N3>N2>N1) with the increase in the percentage of postponing N topdressing at the full-heading stage. However, the C/N ratios in aboveground vegetative organs showed decreasing trends to different extents (N1>N2>N3) with the increase in the percentage of postponing N topdressing at the maturity stage.”
Point 22: Line 547-548: Did you also do the analysis of different combination of N application technique? Was it different?
Response 22: According to the reviewer’s suggestion, we add different combination of N application technique under irrigation method“Under flooded irrigation, on the basis of 60% base tiller N fertilizer, booting N-fertilizer should account for 40% applied equally at top 4th and 2nd leaf. Under deficit irrigation, however, booting N-fertilizer should account for 20% applied equally at top 4th and 2nd leaf.”
Round 2
Reviewer 2 Report
Thank to the author for the revision. However manuscripts still has lot of formatting and writing error. I would recommend authors to get a proofreading done before final submission.
Here are few minor revision required.
Line 96
When was the water potential measured and when was irrigation done? Please elaborate on how did you maintain water/irrigation treatments.
Line 121
Were those pots feeded with 13 CO2, please correct your sentence and make the point clear.
Line 123
Correct sentence structure.
Line 143
Remove water after irrigation.
Line 145
Change is to was.
Line 149
Change heading to ‘Data collection and analysis’ or something similar
185
Unit of CO2 should be umol mol-1 s-1, please add s-1 to your unit.
Author Response
Dear reviewer,
RE: Manuscript Agronomy-881833
We are pleased to submit our revised manuscript (Agronomy-881833) entitled “Coordinating Postanthesis Carbon and Nitrogen Metabolism of Hybrid Rice through Different Irrigation and Nitrogen Regimes”. Once again, we thank your constructive comments and suggestions. The manuscript has been modified based on your suggestions. We hope that the revision has sufficiently addressed the concerns and the manuscript is acceptable for publication. Please let me know if you have any questions.
Sincerely,
Dr. Yongjian Sun
Response to Reviewer 2 Comments
Point 1: Line 96: When was the water potential measured and when was irrigation done? Please elaborate on how did you maintain water/irrigation treatments.
Response 1: According to the reviewer’s comment, we further explain irrigation treatments: “(Soil Research Institute, Nanjing, China) was installed in each pot to monitor soil water potential. When the equitensiometer readings dropped to the desired value re-watered” in Line 96.
Point 2: Line 121: Were those pots feeded with 13CO2, please correct your sentence and make the point clear.
Response 2: According to the reviewer’s comment, we further modify sentence: “Before flowering, for each treatment (W-N regimes with 12 treatment combinations), included 8 pots were selected form 15 pots labeled with 15N as well as the N0 treatment with No N fertilizer application (control treatment )feed 13CO2.”
Point 3: Line 123: Correct sentence structure.
Response 3: According to the reviewer’s comment, we further modify sentence: “After the isotope labeled at the full-heading stage, 4 pots for each treatment were sampled immediately to analyze d13C and d15N values, and the other 4 pots for each treatment with isotope labeled were sampled to analyze d13C and d15N values at the maturity stage.” in Line 123.
Point 4: Line 143: Remove water after irrigation.
Response 4: According to the reviewer’s comment, we delete “water” after irrigation in Line 143.
Point 5: Line 145: Change is to was.
Response 5: According to the reviewer’s comment, we change “is” to “was” in Line 145.
Point 6: Line 149: Change heading to ‘Data collection and analysis’ or something similar.
Response 6: According to the reviewer’s comment, we change “Measurement items and Methods”to “Data collection and analysis”.
Point 7: Line185: Unit of CO2 should be umol mol-1 s-1, please add s-1 to your unit.
Response 7: According to the reviewer’s comment, we modify the unit of CO2 “µmol mol-1 s-1”.
