The Application of Nitrogen Source in Regulating Lignin Biosynthesis, Storage Root Development and Yield of Sweet Potato
Round 1
Reviewer 1 Report
My major concern with this paper is the statistical analysis. The study was a two-factorial in a split-plot arrangement of treatments but was analyzed as a completely randomized design. Otherwise, the manuscript reads well and is easy to follow. Suggestions are provided to the authors to improve the readability of the manuscript.
Line 11: add a justification/rationale statement
Line 24: what are the applications/implications of these findings?
Line 29: Separate into two sentences. Sweetpotato (Ipomoea batatas L.) is an important tuberous crop [1]. Provide some additional details to qualify this statement.
After seedlings are transplanted, the root primordia in the underground stem procambium differentiate to form adventitious roots [2].
Line 47: Delete “It is believed that”
Line 50: Studies on tobacco (Biemelt et al. [15]) and carrot (Wang et al. [16]) found that
Line 70: Nitrogen source is
Line 74: sources on storage root formation
Line 76: seldomly
Line 82: high yielding
Line 87: were planted
Line 87: “Both cultivars are planted in large areas in China.” can be deleted.
Line 149: Clarify this “smashed and over 40 mesh sieves,”
Line 210: Statistical analysis methods were not clear. In line 102 “This study employed a two-factor split-plot design, with S19 and J23 being assigned 102 to the main plot and the different nitrogen treatments assigned to subplots.” In line 117 “The six treatment groups, each in quadruplicate, were randomly allocated to different subplots.” The experiment was not a completely randomised design and therefore needs to be analyzed appropriately. What were the fixed and random effects?
Line 217: various nitrogen sources
Line 222: Treatments N0, AN and XN need to be spelled out in the title or footnotes. Similar comment for Lines 241, 254, 269, 279, 294, . Consider lettering figures with multiple panels, A, B, C, D, etc. Do not use abbreviations in figure captions.
Line 229: replace resembled with ‘was similar’
Line 272: The GA3 content in the potential storage roots of both 272 cultivars decreased with root growth (Figure 4).
Line 306: the potential storage roots treated with ammonium nitrogen
Author Response
Thank you very much for your suggestions and constructive comments.
Response
My major concern with this paper is the statistical analysis. The study was a two-factorial in a split-plot arrangement of treatments but was analyzed as a completely randomized design. Otherwise, the manuscript reads well and is easy to follow. Suggestions are provided to the authors to improve the readability of the manuscript.
Answer: Thank you for your objective comments. We revised as ‘The analysis was carried out according to a two-factor split-plot design with three replications.’
Line 11: add a justification/rationale statement
Answer: Thank you for your objective comments. We added as ‘The understanding of the effects of nitrogen sources on lignin synthesis in sweetpotato during storage root formation is limited.’
Line 24: what are the applications/implications of these findings?
Answer: Thank you for your objective comments. We added as ‘These results indicated that the ammonium nitrogen can inhibit root lignin synthesis, then promote storage root formation and increase yield of sweetpotato.’
Line 29: Separate into two sentences. Sweetpotato (Ipomoea batatas L.) is an important tuberous crop [1]. Provide some additional details to qualify this statement.
After seedlings are transplanted, the root primordia in the underground stem procambium differentiate to form adventitious roots [2].
Answer: Thank you for your objective comments. We revised as ‘Sweetpotato (Ipomoea batatas L.) is an important tuberous crop, ranks after potato and cassava in the world [1]. After seedlings are transplanted, the root primordia in the underground stem procambium differentiate to form adventitious roots [2].’
Line 47: Delete “It is believed that”
Answer: Thank you for your objective comments. We did.
Line 50: Studies on tobacco (Biemelt et al. [15]) and carrot (Wang et al. [16]) found that
Answer: Thank you for your objective comments. We have revised.
Line 70: Nitrogen source is
Answer: Thank you for your objective comments. We have revised.
Line 74: sources on storage root formation
Answer: Thank you for your objective comments. We have revised.
Line 76: seldomly
Answer: Thank you for your objective comments. We have revised.
Line 82: high yielding
Answer: Thank you for your objective comments. We have revised.
Line 87: were planted
Answer: Thank you for your objective comments. We have revised.
Line 87: “Both cultivars are planted in large areas in China.” can be deleted.
Answer: Thank you for your objective comments. We have deleted.
Line 149: Clarify this “smashed and over 40 mesh sieves,”
Answer: Thank you for your objective comments. We revised as ‘smashed the dry roots and sieved with a 40 mesh sieve’.
Line 210: Statistical analysis methods were not clear. In line 102 “This study employed a two-factor split-plot design, with S19 and J23 being assigned 102 to the main plot and the different nitrogen treatments assigned to subplots.” In line 117 “The six treatment groups, each in quadruplicate, were randomly allocated to different subplots.” The experiment was not a completely randomised design and therefore needs to be analyzed appropriately. What were the fixed and random effects?
Answer: Thank you for your objective comments. We revised as ‘The analysis was performed as a two-factor split-plot design.’
Line 217: various nitrogen sources
Answer: Thank you for your objective comments. We have revised.
Line 222: Treatments N0, AN and XN need to be spelled out in the title or footnotes. Similar comment for Lines 241, 254, 269, 279, 294, . Consider lettering figures with multiple panels, A, B, C, D, etc. Do not use abbreviations in figure captions.
Answer: Thank you for your objective comments. We have revised.
Line 229: replace resembled with ‘was similar’
Answer: Thank you for your objective comments. We have revised.
Line 272: The GA3 content in the potential storage roots of both 272 cultivars decreased with root growth (Figure 4).
Answer: Thank you for your objective comments. We have revised.
Line 306: the potential storage roots treated with ammonium nitrogen
Answer: Thank you for your objective comments. We have revised.
Reviewer 2 Report
Meng and co-authors investigated the nitrogen apply on sweetpotato root growth and development. They observed that ammonium nitrogen apply increased the yield and which could be linked to the lignin biosynthesis difference when compared with control or amide nitrogen treatments. My comments:
1, why ammonium and amide nitrogen was selected in this study? I can understand that the fertilizer often used are ammonium or amide nitrogen, but why nitrification inhibitor was applied in the same time? To my knowledge, the sweetpotato may prefer NO3-N.
2, what is the main difference of the two cultivars used in this study? I noticed that the yield difference between the treatments was mostly with S19 cultivar, while there was similar increase between AN and XN when compared with the control treatment.
2,the title must be changed, for example “The application of nitrogen source in regulating storage root development, lignin biosynthesis and yield of sweetpotato”.
3, Line 12-13, remove “and the number of storage roots formed per plant”.
4,line19-21, the sentence of “these genes increased…” need to be specified?
5, Line21, what is the opposite effects?
6, Table 1, why the unit of “°F” was used, I think “°C” should be used.
7, line 207, what is “genetic data”? the primers may go to the text or in the supplementary data.
8, the legends are simplified, more details needed. How many replicates, error bars, statistically analysis and so on….
Author Response
Thank you very much for your suggestions and constructive comments.
Response
1, why ammonium and amide nitrogen was selected in this study? I can understand that the fertilizer often used are ammonium or amide nitrogen, but why nitrification inhibitor was applied in the same time? To my knowledge, the sweetpotato may prefer NO3-N.
Answer: Thanks. As you said, ammonium nitrogen and amide nitrogen are commonly used nitrogen fertilizers. And sweetpotato can absorb ammonium nitrogen directly. Amide nitrogen is often converted to ammonium nitrogen by urease and is absorbed by sweetpotato.
2, what is the main difference of the two cultivars used in this study? I noticed that the yield difference between the treatments was mostly with S19 cultivar, while there was similar increase between AN and XN when compared with the control treatment.
Answer: Thank you for your objective comments. ‘Shangshu 19’ and ‘Jixu 23’ are planted in large areas in China, The number of storage roots of S19 is significantly higher than that of J23.
3, the title must be changed, for example “The application of nitrogen source in regulating storage root development, lignin biosynthesis and yield of sweetpotato”.
Answer: Thank you for your objective comments. We have revised.
4, Line 12-13, remove “and the number of storage roots formed per plant”.
Answer: Thank you for your objective comments. We have revised.
5, line19-21, the sentence of “these genes increased…” need to be specified?
Answer: Thank you for your objective comments. We have revised as ‘And then increased gibberellic acid and decreased zeatin riboside content, enhanced phenylalanine ammonia lyase and peroxidase activities, and promoted lignin synthesis in potential storage roots.’
6, Line21, what is the opposite effects?
Answer: Thank you for your objective comments. We have revised as ‘The opposite effects of ammonium nitrogen treatment on genes expressions, hormones content and enzymes activity were observed in the late stages of storage root formation.’
7, Table 1, why the unit of “°F” was used, I think “°C” should be used.
Answer: Thank you for your objective comments. We have revised.
8, line 207, what is “genetic data”? the primers may go to the text or in the supplementary data.
Answer: Thank you for your objective comments. We have revised.
9, the legends are simplified, more details needed. How many replicates, error bars, statistically analysis and so on….
Thank you for your objective comments. We have revised.
Round 2
Reviewer 2 Report
Thanks the authors for the revision!
I have little comment about the figure legend, what is "Error bars represent 1 SD (n = 3) within the same column...."? what do you mean "1 SD"?
Author Response
Thank you very much for your objective comments.
We revised as 'Error bars represent standard error of the mean (three biological repeats)'
