Comparing Chlorophyll Fluorescence and Hyperspectral Indices in Drought-Stressed Young Plants in a Maize Diversity Panel
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
This manuscript used Chlorophyll Fluorescence and Hyperspectral Indices for drought-stressed plants analysis. After a carefully evaluation, I suggested that it should be rejected.
1. Most of the cited references are outdated. Quite a lot references before 2010 was used. Based on such information, how to summarize the latest progress of this topic?
2. The topic itself is also outdated. There are quite a lot drought stress dertermination methods published. However, this study only analyzes/searches the drought-related indices, which is even a retrogress. No decision-making method for drought stress determination was metioned.
3. Line 355, incomplete sentence.
4. All used methods have already been studied for quite a long time. So many PCA plots are added in the manuscript. No new information can be found.
Author Response
This manuscript used Chlorophyll Fluorescence and Hyperspectral Indices for drought-stressed plants analysis. After a carefully evaluation, I suggested that it should be rejected.
- Most of the cited references are outdated. Quite a lot references before 2010 was used. Based on such information, how to summarize the latest progress of this topic?
RESPONSE: Some outdated references were removed and recent references were added where applicable.
- The topic itself is also outdated. There are quite a lot drought stress dertermination methods published. However, this study only analyzes/searches the drought-related indices, which is even a retrogress. No decision-making method for drought stress determination was metioned.
RESPONSE: In our opinion, the relationships between chlorophyll fluorescence and hyperspectral indices are still not completely clear and they even changed in our experiments by the severity of drought stress.
- Line 355, incomplete sentence.
RESPONSE: Sentence completed.
- All used methods have already been studied for quite a long time. So many PCA plots are added in the manuscript. No new information can be found.
RESPONSE: In our opinion, the relationships between chlorophyll fluorescence and hyperspectral indices are still not completely clear and they even changed in our experiments by the severity of drought stress.
Reviewer 2 Report
Comments and Suggestions for Authors
The paper “Comparing Chlorophyll Fluorescence and Hyperspectral Indices in Drought-Stressed Young Plants of a Maize Diversity Panel” illustrates the use of different phenotypic indices to evaluate the drought stress in young maize plants.
The Authors organized the experiment considering three measurements during the growing period, from 14 to 26 days after planting, to register the changes in the plants’ response to stress and evaluate the most efficient indices to measure it. They chose a set of 165 maize lines from seven different gene pools, to evaluate also the differences due to their genetic origin.
The experiment is well described and all the parameters used as indices are supported by a reference. Surely the approach in studying the effects of drought stress is interesting, but the Figures in the text are not clear.
Figure 1: in my opinion the colour differences among the groups do not allow to distinguish them easily. I consider much more explicative Figure 2, which reports the loadings of each parameter, and offers the same information as Figure 1 but is more understandable.
Figures 4-6: the names of the vectors cannot be read, because they are overlapping. As one of the points of this manuscript is to show the variation of importance of the different indices along the drought stress, they must be distinguished clearly on the diagram. Maybe it could be more convenient to use smaller dots to indicate the maize lines and use a numbered legend to indicate the names of the vector.
I therefore suggest accepting the manuscript after the revision of the Figures.
Author Response
The paper “Comparing Chlorophyll Fluorescence and Hyperspectral Indices in Drought-Stressed Young Plants of a Maize Diversity Panel” illustrates the use of different phenotypic indices to evaluate the drought stress in young maize plants.
The Authors organized the experiment considering three measurements during the growing period, from 14 to 26 days after planting, to register the changes in the plants’ response to stress and evaluate the most efficient indices to measure it. They chose a set of 165 maize lines from seven different gene pools, to evaluate also the differences due to their genetic origin.
The experiment is well described and all the parameters used as indices are supported by a reference. Surely the approach in studying the effects of drought stress is interesting, but the Figures in the text are not clear.
Figure 1: in my opinion the colour differences among the groups do not allow to distinguish them easily. I consider much more explicative Figure 2, which reports the loadings of each parameter, and offers the same information as Figure 1 but is more understandable.
RESPONSE: Colour scheme of the graph is changed in order to be more distinguishable and easier to interpret.
Figures 4-6: the names of the vectors cannot be read, because they are overlapping. As one of the points of this manuscript is to show the variation of importance of the different indices along the drought stress, they must be distinguished clearly on the diagram. Maybe it could be more convenient to use smaller dots to indicate the maize lines and use a numbered legend to indicate the names of the vector.
RESPONSE: Biplots for each measurement were adjusted to provide a clearer image of data. Vector labels were spaced apart to assure readability. Size of vector arrowheads and dots were adjusted.
Reviewer 3 Report
Comments and Suggestions for Authors
The manuscript presents an interesting study on the effect of climate change on corn development. The effect of drought was assessed using two stress indices. Some suggestions were made to improve the manuscript for publication:
a) reduce the Introduction. It is too long and I believe that some paragraphs with the same concept could be unified (such as paragraphs 1 and 2 L30-48).
b) try to rewrite and clarify the ideas in the long paragraphs. The text needs to be more direct and succinct (I highlighted this in paragraph 3 of the Introduction L49-65), but a review should be made in all paragraphs of the text, as too many ideas and long paragraphs make the text confusing.
c) balance the writing and equalize the texts. Paragraphs that are excessively long and have too many ideas (such as in L66-89) and paragraphs that are too short (such as L102-104). review the entire text.
d) Could images of the genotypes and analyses be included in the methodology? It would be interesting if there were more descriptions of the analysis systems and a detailed visual approach to the research.
e) The Measurements topic in the methodology can be broken down into two or three smaller paragraphs.
f) Figures 1, 2, 4, 5 and 6 have overlapping and small captions. I suggest readjusting the font size and organizing the names to allow the reading of the vectors and variables.
g) The caption for Figure 2 needs to be revised to a standard journal.
h) Does the work not present a conclusion? I suggest summarizing a final topic with the main conclusions. It should respond to the research objective adequately and relate the importance of the findings to the research area.
i) How does the research fill a gap in science? This needs to be clear to justify publishing the manuscript.
j) Major revisions and additions should be made to the theoretical framework (more current and comprehensive references were not explored).
Comments for author File: 
Comments.pdf
Comments on the Quality of English Language
Many long, unbalanced and sometimes confusing paragraphs.
Author Response
The manuscript presents an interesting study on the effect of climate change on corn development. The effect of drought was assessed using two stress indices. Some suggestions were made to improve the manuscript for publication:
a) reduce the Introduction. It is too long and I believe that some paragraphs with the same concept could be unified (such as paragraphs 1 and 2 L30-48).
RESPONSE: Paragraphs are joined, and the text was somewhat reduced.
- b) try to rewrite and clarify the ideas in the long paragraphs. The text needs to be more direct and succinct (I highlighted this in paragraph 3 of the Introduction L49-65), but a review should be made in all paragraphs of the text, as too many ideas and long paragraphs make the text confusing.
RESPONSE: Long paragraphs were shortened where possible, to contain only information deemed necessary for given paragraph.
- c) balance the writing and equalize the texts. Paragraphs that are excessively long and have too many ideas (such as in L66-89) and paragraphs that are too short (such as L102-104). review the entire text.
RESPONSE: Paragraphs that could be separated were broken down into more paragraphs to balance the writing and equalize the text. Part of the text was deleted.
- d) Could images of the genotypes and analyses be included in the methodology? It would be interesting if there were more descriptions of the analysis systems and a detailed visual approach to the research.
RESPONSE: Figure S2 (Supplementary material) was added showing the experiment.
- e) The Measurements topic in the methodology can be broken down into two or three smaller paragraphs.
RESPONSE:The Measurements topic was broken down into two paragraphs
- f) Figures 1, 2, 4, 5 and 6 have overlapping and small captions. I suggest readjusting the font size and organizing the names to allow the reading of the vectors and variables.
RESPONSE: Figures were adjusted to provide a clearer image of data provided. Vector labels were spaced apart to assure readability and size of vector arrowheads were adjusted as well.
- g) The caption for Figure 2 needs to be revised to a standard journal.
RESPONSE: Figure 2 caption was changed.
- h) Does the work not present a conclusion? I suggest summarizing a final topic with the main conclusions. It should respond to the research objective adequately and relate the importance of the findings to the research area.
RESPONSE: Conclusion was added.
- i) How does the research fill a gap in science? This needs to be clear to justify publishing the manuscript.
RESPONSE: Last paragraph of Introduction (L116-L117) states the gap in science.
- j) Major revisions and additions should be made to the theoretical framework (more current and comprehensive references were not explored).
RESPONSE: More current references were added where deemed necessary (L43, L60).
Round 2
Reviewer 1 Report
Comments and Suggestions for Authors
/
Author Response
Thank you!
Sincerely,
Vlatko
Reviewer 2 Report
Comments and Suggestions for Authors
I consider that the updated figures are more clear and easier to understand. As this was my main remark about the manuscript, I will suggest to accept it for publication.
Author Response
Thank you!
Sincerely,
Vlatko
Reviewer 3 Report
Comments and Suggestions for Authors
I believe that the manuscript still needs to be modified in important points of minor revisions:
a) The supplementary images (Figure S2) could be included in the manuscript, as they represent an important cycle of the experiment.
b) An additional image should be assembled to describe the complete experimental procedure, detailing each stage of the research.
c) Figure 1 still has overlaps and fonts that are difficult to read.
d) Figure 3 could have the description of the variables enlarged, and if possible the indexes as well. It is difficult to read.
e) Figure 4 has small fonts in the description of the X and Y axes (PC1 and PC2). If possible, increase and improve the resolution.
f) Figures 5 and 6 have the same problem as Fig 1, overlapping captions and difficulty in understanding the results.
g) The discussion failed to relate cause and effect of the different responses by corn genotypes. This would enrich the manuscript more.
h) The conclusions failed to relate the differences with the different applications of these indexes in a practical way. What is the implication of using different genotype indices without correction? What is the relevance of the research for this branch of science? It is worth highlighting the contribution of this research.
Author Response
- a) The supplementary images (Figure S2) could be included in the manuscript, as they represent an important cycle of the experiment.
RESPONSE: The supplementary image was incorporated into Materials and methods (new Figure 2).
- b) An additional image should be assembled to describe the complete experimental procedure, detailing each stage of the research.
RESPONSE: Additional image in form of schematic visualization was added to illustrate the progression of the experiment (new Figure 1.)
- c) Figure 1 still has overlaps and fonts that are difficult to read.
RESPONSE: Labels were spaced apart in order to address overlapping, the font was increased in order to improve readability
- d) Figure 3 could have the description of the variables enlarged, and if possible the indexes as well. It is difficult to read.
RESPONSE: Figure 3 was modified by increasing the font and readability of its contents
- e) Figure 4 has small fonts in the description of the X and Y axes (PC1 and PC2). If possible, increase and improve the resolution.
RESPONSE: Figure 4 was modified by increasing font of x and y axes, and since Figures 5 and 6 had the same format, same was done for them.
- f) Figures 5 and 6 have the same problem as Fig 1, overlapping captions and difficulty in understanding the results.
RESPONSE: Labels were spaced apart in order to address overlapping, the font was increased in order to improve readability
- g) The discussion failed to relate cause and effect of the different responses by corn genotypes. This would enrich the manuscript more.
RESPONSE: Thank you for this comment. After brief description of different responses at the population level, one sentence was added for further explanation (L363-365).
- h) The conclusions failed to relate the differences with the different applications of these indexes in a practical way. What is the implication of using different genotype indices without correction? What is the relevance of the research for this branch of science? It is worth highlighting the contribution of this research.
RESPONSE: Two sentences were added in that regard.
