Comparative Study of Cypripedium Plant Photosynthetic Characteristics from Changbai Mountain

Round 1

Reviewer 1 Report

The manuscript “Comparative Study of Cypripedium Plant Photosynthetic Characteristics from Changbai Mountain” deals with morphological and physiological characteristics of ten different species of Cypripedium. It provides useful information for conservation of this plant species.

The manuscript is well drafted. However, there are some major concerns:

 

It would be good to have more information on the links between the assessed parameters (e.g. chlorophyll, sugars, proteins) in the Introduction.

Line 62: Did you use a specific formula for calculating the leaf area?

Line 70: Which device did you use for the chlorophyll fluorescence analysis?

Lines 76-77: Which protocols were used for determination of photosynthetic products?

Lines 78-81: Which tests were used?

Line 98: It is not clear why the flower color impacts the morphological characteristics of the plants. Can you please explain this?

All figures and tables: What do you show? Averages with standard deviation? What is the number of replicates? Please add the information.

Figure 2 shows the same information as table 2. Please delete one item.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Overall

The focus of the manuscript is appropriate for the journal. But there is a lot of description missing from the Methods and Results that make the results difficult to interpret and the Discussion should be more focused on the horticultural applications of the work.

 

The researchers describe that they are interested in elucidating the light responses of the studied species to guide artificial selection and cultivation. But it is unclear how diurnal fluctuations in photosynthetic measures (which are typical in plants) translate into overall light availability preferences. Potentially, a species could be adapted to high-light availabilty but for a low duration, while another species could be adapated to low-light availability but for longer duration. How would these differences be elucidated from this study? A better approach would have been to measure photosynthesis of each individual to gradually increasing levels of light (i.e., from 0 to 1500 umol photons m-2 s-1) and then model factors like maximum photosynthetic rate, light compensation point, light saturation estimate, quantum efficiency, etc. to elucidate adaptations to light environment.

 

Either in the Introduction or in a ‘Study Species’ subsection of the Methods, there should be description of the species included in the study beyond the basic information presented in Table 1. In particular, information about the commonness vs. rarity and habitat associations of each species if known should be described.

 

Tradeoffs between growth and reproduction (i.e., flowers) in the context of horticulture should be discussed. Is the aim of cultivation to produce vegetative plants or plants with lots of flowers? How would these distinction affect the results/applicability of the study?

 

I think there is opportunity for this study to examine associations between species commonness vs. rarity, habitat associations, and light responses that should be explored. For example, are rares species associated with more restricted light environment associations or specific ranges of photosynthetic light responses?

 

 

Abstract

The justification for the study should be conveyed early in the Abstract. The abstract make the scope of the work clear, but not its importance/motivation until the last sentence. I suggest some reorganization to make the importance/motivation a focus.

 

 

Introduction

The phrase ‘better light conditions’ in line 28 should be explained. What does ‘better’ mean in this context?

 

 

Methods

The ‘experimental material’ referred to in line 47 should be better described in this sentence. Was the material seeds, leaves, whole plants, etc.?

 

The phrase ‘consistent water’ in line 49 needs more description in the Methods (similar to how fertilization is described with specific details).

 

Why is the ‘Numbering’ column relevant in Table 1? I suggest that this column, which seems to refer to specific labeling used in this study, be removed from the table. In general, the information presented in Table 1 seems arbitrary. Why is sepal color and labellum color relevant to the study with enough importance to be listed in the table but not other aspects of the species and/or their habitats?

 

Where were the specific collection locations for each species? Or if this information cannot be provided explicitly due to conservation concerns, can an approximation be given? Was each species sampled from throughout its range or from one population/occurrence?

 

More information about the ‘garden base’ in line 84 should be provided. Were the plants potted? Separated by species? All planted together in the same bed? Etc.?

 

Do the plant counts referred to in line 89 reflect a measure of germination success? Or transplant success? It’s unclear why counts were made in a controlled experiment.

 

Was specific leaf area calculated for the plants? If so, this should be described in the Methods. It’s a common trait to include in studies of light response. If not, I would suggest that this be acknowledged and the need for non-destructive measurements be described in the Methods.

 

Were photosynthesis measurements staggered across species? Or was the same species the focus for each set of measurements? Across what total time period were photosynthesis measurements made? These details are important to assess whether age effects could have influenced results.

 

Were photosynthesis measurements made only with ambient light availaiblity or were they made across a range of light availability (with the use of an external lamp, for example)? Without the latter, it would be difficult to ascerrtain the light ‘preferences’ of each species and/or to determine that they are experiencing photoinhibition.

 

The Methods used for the determination of photosynthetic products in lines 76-77 need to be described. The description of ‘chlorophyll’ as a photosynthetic product seems inaccurate.

 

 

Results

Are the mean values presented in Table 2 shown with standard errors or standard deviations? Are these species values? If so, the ‘treatment’ column should more clearly show the species’ names. The labeling regime of the study is not the focus.

 

While informative, it isn’t clear why the comparisons of morphology between the species as presented in the first two paragraphs of the Results is important. These results should be presented within the context of light. Also please use species names throughout the manuscript rather than the specific labels that you used for each species. It is confusing to read through the results while having to refer back to Table 1 to gather this information.

 

Was a plant morphological ‘index’ used (line 99)? Or do these results refer to the multiple plant morphological traits/measures that were assessed? This should be clarified.

 

Figure 2 and Table 2 are redundant (i.e., the represent a double depiction of the same results). One of these should be eliminated from the manuscript.

 

I suggest that Figure 3 be presented as a line/curve graph rather than a bar graph since it is reasonable to infer the relationship between two distinct measurement times. You could use one line of a different color for each species. This would make the figure much easier to read and interpret and differences between species to be clearer. You could use the same colors for each species in all of the Figures for consistency.

 

The PCA results could be presented more clearly and concisely.

 

 

Discussion

Light is generally not considered a ‘climatic factor’ (i.e., climate is temperature and precipitation) so line 218 should be revised.

 

Since the focus of the paper is on horticulture, I think that it would be most pertinent to present the Discussion in subsections focused on each species and/or similar groups of species organized by their growth requirements rather than a Discussion of each results section in this manuscript. This would faciliate the capacity of this research to inform horticulture (i.e., to provide clear guidance for horticulturalists). As written, I would have difficulty gathering horticultural information for each species from the Discussion.

 

The word ‘materials’ in line 219 should be clarified.

 

Was ‘construction cost’ (line 222) actually calculated in this study, and if so, how?

 

Lines 263-268 present results, not a discussion of results. Such comparisons should be described in the Results section.

Tradeoffs between growth and reproduction (i.e., flowers) in the context of horticulture should be discussed. Is the aim of cultivation to produce vegetative plants or plants with lots of flowers? How would these distinction affect the results/applicability of the study?

Author Response

Please see the attachment.

Author Response File: Author Response.docx