Seasonal Fluctuation of Non-Structural Carbohydrates in Different Organs of Four Tree Species in Subtropical Forests
, Xiao Suo 5 and Xiali Guo 1,*
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors1. Line 74. We aimed to 1) investigate the seasonal pattern of the concentrations of NSC, SS, and ST of four tree species and 2) compare the species-specific differences in NSC, SS, and ST concentrations at the organ and tree level. Please remove the number in the objective. We aimed to investigate the seasonal pattern of the concentrations of NSC, SS, and ST of four tree species and compare the species-specific differences in NSC, SS, and ST concentrations at the organ and tree level.
2. All references should be numbered. Please follow the journal template.
3. Line 105. After that, the blank was used as a control, and the absorbance was measured at a wavelength of 625 nm. Please provide information on what kind of solution is used for blank. Information on the UV visible spectrometer used in this study (name, brand, etc.) should be included.
4. Line 116. This study uses a significance level of 0.05 (5%). However, the results and discussion also use other levels (0.1% and 1%).
5. Figure 3. I suggested the authors change the legend color of the root and tree. Both colors are pretty similar.
Author Response
Reviewer 1
- Line 74. We aimed to 1) investigate the seasonal pattern of the concentrations of NSC, SS, and ST of four tree species and 2) compare the species-specific differences in NSC, SS, and ST concentrations at the organ and tree level. Please remove the number in the objective. We aimed to investigate the seasonal pattern of the concentrations of NSC, SS, and ST of four tree species and compare the species-specific differences in NSC, SS, and ST concentrations at the organ and tree level.
Response：Thanks for your comments. According to the revised version, we have deleted the numbers in the research objectives as required.
- All references should be numbered. Please follow the journal template.
Response：According to the revised version, we have revised the reference format in accordance with the journal template.
- Line 105. After that, the blank was used as a control, and the absorbance was measured at a wavelength of 625 nm. Please provide information on what kind of solution is used for blank. Information on the UV visible spectrometer used in this study (name, brand, etc.) should be included.
Response：Thanks for your comments. There is ambiguity in using the blank as a control, we have deleted it and provided the name and brand-related information of the UV-visible spectrometer.” The contents of soluble sugar and starch were determined using the anthrone colorimetric method. Absorbance was measured by ultraviolet-visible spectrometer (Instrument types: Ultrospec2100pro) at 630 nanometers to calculate the contents of soluble sugar and starch based on the glucose standard curve. The content of nonstructural carbohydrates was calculated as the sum of the contents of soluble sugar and starch[18]”
- Line 116. This study uses a significance level of 0.05 (5%). However, the results and discussion also use other levels (0.1% and 1%).
Response：According to the results section, we rephased the sentence in the statistical methods as “one-way analysis of variance (ANOVA) and least significant difference (LSD) were used to analyze the differences in the concentrations of NSC”.
- Figure 3. I suggested the authors change the legend color of the root and tree. Both colors are pretty similar.
Response：According to the revised version, we delete the NSC concentrations at tree level and the new figure is as below.
Reviewer 2
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsComments for manuscript forests-3418693
The main purpose of the study was to analyze seasonal changes in non-structural carbohydrates (NSC) concentrations in different organs of two coniferous and two broad-leaved trees in subtropical region of China. The research subject is original especially concidering climate change.
It is recommended to put authors after Latin names of the trees in Abstract and in the Introduction section. It is recommended not to omit the word concentration/quantity/level etc., because the compounds themselves can not be higher or have seasonal dynamics. Besides, it is better to use the same terms throughout the text: broad-leaved or broadleaf, stem or trunk.
Title: the word carbohydrate should be changed to carbohydrates.
Introduction: authors should review and give more information about NSC in Nothotsuga longibracteata, Pinus kwangtungensis, Schima superba, and Betula alnoides or in related species.
Materials and Methods: authors should put DOY in subsection 2.2 soon after dates listing. Besides, they should give information about weight of one sample of every plant organ, extraction procedure, biochemical analyses, and measuring units for expression the obtained results. What was done according to E.A. Newell, S.S. Mulkey, and S.J. Wright (2002)? Now it is not clear why anthrone-sulfuric acid method was chosen as it is used for sucrose determination and not for NSC, soluble sugars, and starch which are compounds of interest. The authors must refine the information given according to G. Hoch, A. Richter, and Ch. Körner (2003). In Table 1 the column Sample size may be deleted as this information is present in the text. For what reason wood properties are given? How can they be discussed?
Results: authors should explain after each figure and table what do asterisks and small letters mean. They also should add what weight (fresh or dry) was used for expression the obtained results. It is recommended to put the compounds of interest in one order throughout the text, tables, and figures. How Figure 1b results were obtained? They seem to be low compared to other results. They need to be presented in the figure and in the main text more clearer. For Table 3 it should be given interpretation for all abbreviations used. In Figure 2d the Y-axis should be entitled differently.
The literature is cited not according to Instructions for authors.
Considering the above comments and the quality of English language of the manuscript, it is suggested to rewrite the text.
Comments on the Quality of English LanguageThe English languange of the manuscript need to be improved.
Author Response
Response letter
2
Comments for manuscript forests-3418693
The main purpose of the study was to analyze seasonal changes in non-structural carbohydrates (NSC) concentrations in different organs of two coniferous and two broad-leaved trees in subtropical region of China. The research subject is original especially concidering climate change.
Response：Thanks for your comments.
It is recommended to put authors after Latin names of the trees in Abstract and in the Introduction section. It is recommended not to omit the word concentration/quantity/level etc., because the compounds themselves can not be higher or have seasonal dynamics. Besides, it is better to use the same terms throughout the text: broad-leaved or broadleaf, stem or trunk.
Response：Thank you for your advice. According to the revised version, we put the author after the Latin name of the tree in the abstract and introduction sections.
“we measured the seasonal dynamics of NSC in four tree species (Nothotsuga longibracteata W. C. Cheng, Pinus kwangtungensis Chun ex Tsiang, Schima superba Gardn. et Champ and Betula alnoides Buch. -Ham. ex D. Don)”.
At the same time, words such as concentration/quantity/level were added to indicate the higher concentration level or seasonal dynamics of the compound itself. In addition, we use the same terms throughout the text: broadleaf, trunk.
Title: the word carbohydrate should be changed to carbohydrates.
Response：According to the revised version, we change the carbohydrate in the title to the carbohydrates.
Introduction: authors should review and give more information about NSC in Nothotsuga longibracteata, Pinus kwangtungensis, Schima superba, and Betula alnoides or in related species.
Response：Thanks for your advice. In the Introduction, we have added information on the review of NSC of related species.
“ By monitoring the concentration of NSC in the canopy of Populus tremuloides、Pinus edulis and Juniperus osteosperma in southwestern U.S.A., they found that NSC dynamics was dependent on the species and tissue types [11]. Also, The NSC in stemwood of Acer rubrum during the growing season was highly dynamic and about a decade old[7]. Therefore, the concentration of NSC in plants is an important indicator of the balance between carbon sources and sinks [12]. ”
Materials and Methods: authors should put DOY in subsection 2.2 soon after dates listing. Besides, they should give information about weight of one sample of every plant organ, extraction procedure, biochemical analyses, and measuring units for expression the obtained results. What was done according to E.A. Newell, S.S. Mulkey, and S.J. Wright (2002)? Now it is not clear why anthrone-sulfuric acid method was chosen as it is used for sucrose determination and not for NSC, soluble sugars, and starch which are compounds of interest. The authors must refine the information given according to G. Hoch, A. Richter, and Ch. Körner (2003). In Table 1 the column Sample size may be deleted as this information is present in the text. For what reason wood properties are given? How can they be discussed?
Response：Thanks for your advice. According to the revised version, we put DOY in subsection 2.2 soon after dates listing.” The sampling dates were converted into the number of days from January 1, 2023, expressed as DOY (day of the year). The sampling dates were DOY 70, DOY 143, DOY 196, DOY 252, DOY 316, respectively.”
We revised as “0.2g of the ground sample was combined with 5 mL of distilled water in a test tube. After being placed in a boiling water bath for 30 minutes, the supernatant was collect-ed. This procedure was repeated twice to guarantee complete sugar extraction. The two extracts were placed in a centrifuge tube, and then distilled water was added to reach a constant volume of 25 milliliters. Subsequently, the sediments from the soluble sugar extraction were dried, and perchloric acid was added to extract starch. The con-tents of soluble sugar and starch were determined using the anthrone colorimetric method. Absorbance was measured by ultraviolet-visible spectrometer (Instrument types: Ultrospec2100pro) at 630 nanometers to calculate the contents of soluble sugar and starch based on the glucose standard curve. The content of nonstructural carbo-hydrates was calculated as the sum of the contents of soluble sugar and starch[18].
In addition, we delete the column Sample size and change the 'wood properties' to 'Leaf habitat' in Table 1.
Results: authors should explain after each figure and table what do asterisks and small letters mean. They also should add what weight (fresh or dry) was used for expression the obtained results. It is recommended to put the compounds of interest in one order throughout the text, tables, and figures. How Figure 1b results were obtained? They seem to be low compared to other results. They need to be presented in the figure and in the main text more clear. For Table 3 it should be given interpretation for all abbreviations used. In Figure 2d the Y-axis should be entitled differently.
Response：According to the revised version, we explain after each figure and table what do asterisks and small letters mean. We also add dry weight for expression the obtained results in section 2.2. According to your suggestion, we put the compounds of interest in one order throughout the text, tables, and figures. The results of Figure 1b show the range of concentrations of NSC and its components, and the specific analysis method has been supplemented in Section 2.4. For Table 3, we add interpretation for all abbreviations used. In addition, we change the Y-axis title of Figure 2d to a more appropriate expression.
The literature is cited not according to Instructions for authors.
Response：According to the revised version, we revised the reference citation format according to the journal template.
Considering the above comments and the quality of English language of the manuscript, it is suggested to rewrite the text.
Response：We are grateful for your valuable comments and suggestions. We have carefully revised the manuscript to eliminate language errors and consulted a professional editing service to ensure the language is suitable for the review process.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe paper by Guo at al. is dedicated to the analysis of the seasonal fluctuations in the level of non-structural carbohydrates of (NSC) four tree species including two conifers and two broadleaf species. The authors demonstrated that the concentration of NSC in coniferous trees was higher than that in broad-leaf trees, and in the canopy, it was higher than in other organs. The seasonal changes in the NSC were highlighted. The results are generally sound, and the conclusions are supported by the experimental data. Still the paper needs to be amended. Particularly, the method description is incomplete. There are also some flaws in tables and figures. The text of the manuscript should be proofread carefully.
L. 34: HOCH -> Hoch
L40: shows -> show
LL42-43: it is not clear how the dormant plants can consume MORE NSC than actively vegetating ones. Please clarify.
L50: during the stressed conditions -> under stressful conditions
L83: annual precipitation of 1648 m does not look realistic.
LL93-95: please provide additional details about the sampling i.e. number of leaves picked and the site on the branch where they were picked, part of the canopy from which they were taken, the sites of trunk parts sampling etc.
Table 2 and Fig. 2: what is the meaning of the asterisks?
Section 3.2: please provide the description of the methods for differentiation between the SS, ST.
Table 3: what is the meaning of the “R_” prefix?
Fig. 3 lacks the results of statistical treatment.
L196: accumulates -> accumulate
L189: felled -?
L201: how trunk can be the main organ of carbon fixation and not leaf, as one would expect?
Author Response
Reviewer 3
The paper by Guo at al. is dedicated to the analysis of the seasonal fluctuations in the level of non-structural carbohydrates of (NSC) four tree species including two conifers and two broadleaf species. The authors demonstrated that the concentration of NSC in coniferous trees was higher than that in broad-leaf trees, and in the canopy, it was higher than in other organs. The seasonal changes in the NSC were highlighted. The results are generally sound, and the conclusions are supported by the experimental data. Still the paper needs to be amended. Particularly, the method description is incomplete. There are also some flaws in tables and figures. The text of the manuscript should be proofread carefully.
Response：Thank you for your comments. According to your suggestion, we carefully proofread the text of the manuscript, and supplemented and corrected the material method part and the icon.
- 34: HOCH -> Hoch
Response：According to the revised version, we modify the 'HOCH' to 'Hoch' in the full text.
L40: shows -> show
Response：According to the revised version, we modify the 'shows' to 'show'.
LL42-43: it is not clear how the dormant plants can consume MORE NSC than actively vegetating ones. Please clarify.
Response：Thanks for your advice. We delete 'consume less NSC through respiration' to make the expression more accurate and clear. Trees can accumulate more NSC through photosynthesis during the growing season, and the NSC produced is greater than the NSC consumed by respiration. During the dormant season ( winter ), trees cannot perform photosynthesis normally. In order to resist the cold outside, they can only maintain their own stability by breathing a large amount of NSC accumulated before consumption.
L50: during the stressed conditions -> under stressful conditions
Response：According to the revised version, we modify the 'during the stressed conditions' to 'under stressful conditions'.
L83: annual precipitation of 1648 m does not look realistic.
Response：According to the revised version, we modify the '1648 m' to '1648 mm'.
LL93-95: please provide additional details about the sampling i.e. number of leaves picked and the site on the branch where they were picked, part of the canopy from which they were taken, the sites of trunk parts sampling etc.
Response：According to the revised version, we added a more detailed description of the sampling method and location of the three parts of the canopy, trunk and root In section 2.2. “On the sunny side of the tree, three healthy branches were selected from the upper part of the canopy, and 5 leaves were picked from each branch. Using a growth cone with an inner diameter of 5.15 mm, samples were collected at the breast height (1.3 m) of the trunk. Coarse roots (2 < d < 10 mm) and fine roots (d < 2 mm) were collected by manual excavation.”
Table 2 and Fig. 2: what is the meaning of the asterisks?
Response：According to the revised version, we note the specific meaning of the asterisk in Table 2 and Fig. 2.
Note: ***: p < 0.001; **: p < 0.01.
Section 3.2: please provide the description of the methods for differentiation between the SS, ST.
Response：According to the revised version, we provide the description of the methods for differentiation between the SS, ST in section 2.
Table 3: what is the meaning of the “R_” prefix?
Response：According to the revised version, we removed the prefix “R _ “, and the new Table 3 is as below.
Table 3. Analysis of the difference of concentrations of NSC and its components in different organs of tree species and the difference of range in the year.
|
Species |
Organ |
Concentrations |
The range of concentrations |
||||
|
SS (mg/g) |
ST (mg/g) |
NSC (mg/g) |
SS (mg/g) |
ST (mg/g) |
NSC (mg/g) |
||
|
N. longibracteata |
canopy |
73.343±4.306a |
60.244±2.038a |
133.587±4.731a |
55.049±4.786a |
28.463±4.375a |
63.624±4.769a |
|
root |
72.734±3.545a |
49.680±1.568b |
122.414±4.192a |
50.842±5.004a |
21.813±4.369a |
62.996±3.957a |
|
|
trunk |
56.110±1.999b |
41.484±1.527c |
97.595±2.735b |
28.243±2.191b |
23.691±1.950a |
40.016±2.378b |
|
|
S. superba |
canopy |
80.652±4.948a |
51.586±1.436a |
132.239±5.334a |
70.203±4.843a |
24.565±1.153a |
76.408±7.056a |
|
root |
68.122±4.583b |
51.136±1.778a |
119.259±5.458b |
62.571±6.254a |
23.940±4.667a |
69.294±11.211a |
|
|
trunk |
43.734±1.448c |
44.366±1.110b |
88.100±1.841c |
24.505±1.386b |
18.863±2.331a |
33.908±2.550b |
|
|
P. kwangtungensis |
canopy |
82.461±6.005a |
54.686±1.291a |
137.148±6.723a |
84.866±12.718a |
21.792±2.553a |
94.404±16.682a |
|
root |
62.193±3.422b |
49.350±1.572b |
111.544±4.454b |
45.789±6.092b |
19.763±3.724a |
53.326±9.329b |
|
|
trunk |
46.903±2.212c |
48.950±1.634b |
95.853±2.518c |
38.638±2.193b |
27.934±2.339a |
46.750±4.784b |
|
|
B. alnoides |
canopy |
67.564±3.848a |
57.470±2.950a |
125.034±5.473a |
49.385±3.438a |
38.118±4.952a |
71.061±4.614a |
|
root |
56.042±3.575b |
41.817±1.595b |
97.8604±4.667b |
52.557±3.600a |
26.323±2.241a |
70.878±3.243a |
|
|
trunk |
43.230±2.403c |
42.783±2.235b |
86.013±4.275b |
31.658±2.240b |
31.549±3.042ab |
59.441±4.975a |
|
Note: Different lowercase letters indicate that there are significant differences in the concentrations of NSC and its components in different organs of tree species and range in the year (p < 0.05). SS: soluble sugar; ST: starch; NSC: non-structural carbohydrates.
Fig. 3 lacks the results of statistical treatment.
Response: Thank you for your advice. According to your suggestion, we processed the statistical results of Fig. 3, and summarized the intra-annual change of total NSC concentrations in canopy, root and trunk.
L196: accumulates -> accumulate
Response：According to the revised version, we modify the 'accumulates' to 'accumulate'.
L189: felled -?
Response：Thanks for your advice. Since the word ' felled ' is not accurate, we changed ' felled ' to ' shed ' according to the revised version to express that deciduous broadleaf tree species resist cold through natural leaf fall.
L201: how trunk can be the main organ of carbon fixation and not leaf, as one would expect?
Response：Thanks for your advice. According to the revised version, we change the ' fixation' to ' storage' . In photosynthesis, leaves absorb CO2 and convert it into NSC, which is a key step in tree carbon sequestration. As the supporting structure of trees, the trunk mainly plays the role of storing NSC.
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsComments for manuscript forests-3418693
The revised manuscript has addressed most of my comments and questions. However, there is a need to further address some other criticisms, because not all corrections were made.
The authors for Betula alnoides should be written as Buch.-Ham. Ex D.Don. It is recommended to use the word concentration together with investigated compounds names. There is a need to define what weight (fresh or dry) was used for expression the obtained results. Now it is not clear both from Materials and Methods subsection and from Results subsection.
Introduction: Populus tremuloides, Pinus edulis, Juniperus osteosperma, and Acer rubrum should be written in Italics.
Materials and methods: The study region belongs to the southern tropical subtropical monsoon climate zone, does not it? Authors should correct their instrument type: it is spectrophotometer, not spectrometer, and add country of origin for this very instrument.
Results: the authors should put the compounds of interest in one order throughout the text, tables, figures, and figure captions. For example, now their order in Table 2, in Figure 1, and in Figure 1 caption is different and it is difficult for readers to quickly and clearly understand the obtained results. In lines 134-139, the authors should refine the information about B. alnoides. Now this information is confusing. In Table 3, the authors should refine small letters (ab) for the range of concentration of ST in B. alnoides trunk. In line 163, the authors should add p.
Considering the above comments, it is suggested to make minor revision.
Comments on the Quality of English LanguageThe English language could be improved.
Author Response
Comments for manuscript forests-3418693
The revised manuscript has addressed most of my comments and questions. However, there is a need to further address some other criticisms, because not all corrections were made.
The authors for Betula alnoides should be written as Buch.-Ham. Ex D.Don. It is recommended to use the word concentration together with investigated compounds names. There is a need to define what weight (fresh or dry) was used for expression the obtained results. Now it is not clear both from Materials and Methods subsection and from Results subsection.
Response: We revised as Betula alnoides Buch. -Ham. Ex D.Don) in subtropical forests at organ level including canopy. We also used the word “concentration” in the text. Dry weight was used and we added this information in the Materials and Methods subsection and from Results subsection.
We added this information
All samples were cleaned and put in a microwave at 105°C for 10 minutes to denature enzymes. After that, these samples were oven-dried to constant weight at 60 °C and then were grounded to powder with a ball mill (Retsch MM400, Germany). 0.2g of the dry samples was combined with 5 mL of distilled water in a test tube.
Introduction: Populus tremuloides, Pinus edulis, Juniperus osteosperma, and Acer rubrum should be written in Italics.
Response: Corrected.
Materials and methods: The study region belongs to the southern tropical subtropical monsoon climate zone, does not it? Authors should correct their instrument type: it is spectrophotometer, not spectrometer, and add country of origin for this very instrument.
Response: We revised as This region belongs to the subtropical monsoon climate zone.
We revised as: Absorbance was measured by ultraviolet-visible spectrophotometer (Ultrospec2100pro, America)
Results: the authors should put the compounds of interest in one order throughout the text, tables, figures, and figure captions. For example, now their order in Table 2, in Figure 1, and in Figure 1 caption is different and it is difficult for readers to quickly and clearly understand the obtained results. In lines 134-139, the authors should refine the information about B. alnoides. Now this information is confusing. In Table 3, the authors should refine small letters (ab) for the range of concentration of ST in B. alnoides trunk. In line 163, the authors should add p.
Response: We put the compounds of interest in order of NSC, SS and ST.
Table 2. The effects of species, organs, season and their interactions on non-structural carbohydrates (NSC), soluble sugar (SS), and starch (ST).
Note: ***: p < 0.001; **: p < 0.01.
|
Components |
Source of Variation |
DF |
F |
P |
|
NSC |
Species |
3 |
20.243 |
0.000*** |
|
Date |
4 |
46.071 |
0.000*** |
|
|
Organ |
2 |
180.191 |
0.000*** |
|
|
Species × date |
12 |
5.315 |
0.000*** |
|
|
Species × organ |
6 |
2.948 |
0.009** |
|
|
Date × organ |
8 |
19.951 |
0.000*** |
|
|
Species × date × organ |
23 |
1.467 |
0.083 |
|
|
SS |
Species |
3 |
18.885 |
0.000*** |
|
Date |
4 |
37.370 |
0.000*** |
|
|
Organ |
2 |
145.612 |
0.000*** |
|
|
Species × date |
12 |
4.381 |
0.000*** |
|
|
Species × organ |
6 |
5.751 |
0.000*** |
|
|
Date × organ |
8 |
27.160 |
0.000*** |
|
|
Species × date × organ |
23 |
1.444 |
0.092. |
|
|
ST |
Species |
3 |
7.275 |
0.000*** |
|
Date |
4 |
23.997 |
0.000*** |
|
|
Organ |
2 |
74.205 |
0.000*** |
|
|
Species × date |
12 |
9.688 |
0.000*** |
|
|
Species × organ |
6 |
9.716 |
0.000*** |
|
|
Date × organ |
8 |
6.379 |
0.000*** |
|
|
Species × date × organ |
23 |
2.286 |
0.001** |
Figure 1. Species specific differences in the concentrations (a) and range (b) of non-structural carbohydrates (NSC), soluble sugar (SS), and starch (ST), at the whole tree level.
We revised the lines 134-139 as:
Generally, the concentrations of NSC, SS, and ST in different organs of the four tree species were shown as canopy > root > trunk (Table 3). No significant difference was found in the concentration of NSC and SS between canopy and root of N. longibracteata. For B. alnoides, there was no significant difference in the concentration of NSC and ST between root and trunk (Table 3). The range of concentration of NSC and ST in the canopy and root were significantly higher than that of trunk for N. longibracteata and S. superba. However, no significant difference was found among canopy, root and trunk of B. alnoides. For P. kwangtungensis, the range of concentration of NSC and SS in the canopy was significantly higher than that in the trunk (Table 3).
We added p Note: Different lowercase letters indicate that there are significant differences at the level of p< 0.05.
Considering the above comments, it is suggested to make minor revision.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors had provided constructive replies to my notes so this manuscript can be published now.
Author Response
Reviewer 3
The paper by Guo at al. is dedicated to the analysis of the seasonal fluctuations in the level of non-structural carbohydrates of (NSC) four tree species including two conifers and two broadleaf species. The authors demonstrated that the concentration of NSC in coniferous trees was higher than that in broad-leaf trees, and in the canopy, it was higher than in other organs. The seasonal changes in the NSC were highlighted. The results are generally sound, and the conclusions are supported by the experimental data. Still the paper needs to be amended. Particularly, the method description is incomplete. There are also some flaws in tables and figures. The text of the manuscript should be proofread carefully.
Response：Thank you for your comments. According to your suggestion, we carefully proofread the text of the manuscript, and supplemented and corrected the material method part and the icon.
- 34: HOCH -> Hoch
Response：According to the revised version, we modify the 'HOCH' to 'Hoch' in the full text.
L40: shows -> show
Response：According to the revised version, we modify the 'shows' to 'show'.
LL42-43: it is not clear how the dormant plants can consume MORE NSC than actively vegetating ones. Please clarify.
Response：Thanks for your advice. We delete 'consume less NSC through respiration' to make the expression more accurate and clear. Trees can accumulate more NSC through photosynthesis during the growing season, and the NSC produced is greater than the NSC consumed by respiration. During the dormant season ( winter ), trees cannot perform photosynthesis normally. In order to resist the cold outside, they can only maintain their own stability by breathing a large amount of NSC accumulated before consumption.
L50: during the stressed conditions -> under stressful conditions
Response：According to the revised version, we modify the 'during the stressed conditions' to 'under stressful conditions'.
L83: annual precipitation of 1648 m does not look realistic.
Response：According to the revised version, we modify the '1648 m' to '1648 mm'.
LL93-95: please provide additional details about the sampling i.e. number of leaves picked and the site on the branch where they were picked, part of the canopy from which they were taken, the sites of trunk parts sampling etc.
Response：According to the revised version, we added a more detailed description of the sampling method and location of the three parts of the canopy, trunk and root In section 2.2. “On the sunny side of the tree, three healthy branches were selected from the upper part of the canopy, and 5 leaves were picked from each branch. Using a growth cone with an inner diameter of 5.15 mm, samples were collected at the breast height (1.3 m) of the trunk. Coarse roots (2 < d < 10 mm) and fine roots (d < 2 mm) were collected by manual excavation.”
Table 2 and Fig. 2: what is the meaning of the asterisks?
Response：According to the revised version, we note the specific meaning of the asterisk in Table 2 and Fig. 2.
Note: ***: p < 0.001; **: p < 0.01.
Section 3.2: please provide the description of the methods for differentiation between the SS, ST.
Response：According to the revised version, we provide the description of the methods for differentiation between the SS, ST in section 2.
Table 3: what is the meaning of the “R_” prefix?
Response：According to the revised version, we removed the prefix “R _ “, and the new Table 3 is as below.
Table 3. Analysis of the difference of concentrations of NSC and its components in different organs of tree species and the difference of range in the year.
|
Species |
Organ |
Concentrations |
The range of concentrations |
||||
|
SS (mg/g) |
ST (mg/g) |
NSC (mg/g) |
SS (mg/g) |
ST (mg/g) |
NSC (mg/g) |
||
|
N. longibracteata |
canopy |
73.343±4.306a |
60.244±2.038a |
133.587±4.731a |
55.049±4.786a |
28.463±4.375a |
63.624±4.769a |
|
root |
72.734±3.545a |
49.680±1.568b |
122.414±4.192a |
50.842±5.004a |
21.813±4.369a |
62.996±3.957a |
|
|
trunk |
56.110±1.999b |
41.484±1.527c |
97.595±2.735b |
28.243±2.191b |
23.691±1.950a |
40.016±2.378b |
|
|
S. superba |
canopy |
80.652±4.948a |
51.586±1.436a |
132.239±5.334a |
70.203±4.843a |
24.565±1.153a |
76.408±7.056a |
|
root |
68.122±4.583b |
51.136±1.778a |
119.259±5.458b |
62.571±6.254a |
23.940±4.667a |
69.294±11.211a |
|
|
trunk |
43.734±1.448c |
44.366±1.110b |
88.100±1.841c |
24.505±1.386b |
18.863±2.331a |
33.908±2.550b |
|
|
P. kwangtungensis |
canopy |
82.461±6.005a |
54.686±1.291a |
137.148±6.723a |
84.866±12.718a |
21.792±2.553a |
94.404±16.682a |
|
root |
62.193±3.422b |
49.350±1.572b |
111.544±4.454b |
45.789±6.092b |
19.763±3.724a |
53.326±9.329b |
|
|
trunk |
46.903±2.212c |
48.950±1.634b |
95.853±2.518c |
38.638±2.193b |
27.934±2.339a |
46.750±4.784b |
|
|
B. alnoides |
canopy |
67.564±3.848a |
57.470±2.950a |
125.034±5.473a |
49.385±3.438a |
38.118±4.952a |
71.061±4.614a |
|
root |
56.042±3.575b |
41.817±1.595b |
97.8604±4.667b |
52.557±3.600a |
26.323±2.241a |
70.878±3.243a |
|
|
trunk |
43.230±2.403c |
42.783±2.235b |
86.013±4.275b |
31.658±2.240b |
31.549±3.042ab |
59.441±4.975a |
|
Note: Different lowercase letters indicate that there are significant differences in the concentrations of NSC and its components in different organs of tree species and range in the year (p < 0.05). SS: soluble sugar; ST: starch; NSC: non-structural carbohydrates.
Fig. 3 lacks the results of statistical treatment.
Response: Thank you for your advice. According to your suggestion, we processed the statistical results of Fig. 3, and summarized the intra-annual change of total NSC concentrations in canopy, root and trunk.
L196: accumulates -> accumulate
Response：According to the revised version, we modify the 'accumulates' to 'accumulate'.
L189: felled -?
Response：Thanks for your advice. Since the word ' felled ' is not accurate, we changed ' felled ' to ' shed ' according to the revised version to express that deciduous broadleaf tree species resist cold through natural leaf fall.
L201: how trunk can be the main organ of carbon fixation and not leaf, as one would expect?
Response：Thanks for your advice. According to the revised version, we change the ' fixation' to ' storage' . In photosynthesis, leaves absorb CO2 and convert it into NSC, which is a key step in tree carbon sequestration. As the supporting structure of trees, the trunk mainly plays the role of storing NSC.
