Morphological, Biochemical, and Physiological Response of Butterhead Lettuce to Photo-Thermal Environments

Round 1

Reviewer 1 Report

Dear authors,

You did a huge work revising the manuscript and it has improved very much. I have no further comments 

Author Response

We are highly grateful to the reviewer for the encouraging remarks.

Author Response File: Author Response.docx

Reviewer 2 Report

Dear Authors,

Please find comments and suggestions in the PDF!

Best regards

Comments for author File: Comments.pdf

Author Response

We are highly grateful to the reviewer for the remarks and suggestions. The manuscript has been revised and updated. The detail is given in the attached file.

Author Response File: Author Response.docx

Reviewer 3 Report

In Chapter 2.4, m2 (instead of m-2) is incorrectly stated in the unit of light intensity, the day-time of the measurements of gasometric parameters is still missing. I recommend checking the added or reworded parts of the text, there are a number of typos.

Author Response

We are highly grateful to the reviewer for the encouraging remarks. All suggestions have been incorporated into the updated manuscript.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Dear authors,

thank you for taking into account all proposed changes and suggestions. I am satisfied and for that I am suggesting acceptance of your paper.

Best regards

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The manuscript describes the effect of photoperiod length, light intensity and temperature on the quantitative and qualitative parameters of butterhead lettuce. Based on the results of the study, the optimal combination of growing conditions can be selected to achieve the best growth and quality of the studied lettuce cultivar. I have the following comments on the manuscript:

1. Line 21: The abbreviations „PCA“ and „FAMD“ mentioned in Abstract should be explained.
2. Lines 21-22: I do not understand the statement: „PCA and FAMD analyses revealed that most of the lettuce attributes were negatively correlated at 11 hours of photoperiod and low light intensity.” What is the correlation (what with what) when one photoperiode and one light intensity are mentioned?
3. Numeric values in the text and in the tables should be rounded accordingly. For example, total leaf area (Table 1, the last column) should be rounded to units (not to hundredths) of cm². The unrounded values make the text more difficult to understand.
4. In general, I have had trouble understanding the description of the results. The description is often inaccurate, it is not clear whether (or when) the authors describe the effect of photoperiod within one light intensity or the effect of light intensity within one photoperiod. A description of the effect of the photoperiod and a description of the effect of light intensity should be distinguished (divided) in the text.

For example, the claims on lines 57-58, 67-68, and 73-74 are not true: Pn, E and WUE did not generally increase with photoperiod and/or light intensity, they only increased with light intensity in the lowest (11 h per day) photoperiod. Similar incorrect generalization occurs in many places in the text.

5. In Table 1, it is not clear which variants are compared in order to determine the statistical significance of the differences, it is not stated what the values are (means and SE?).
6. In my opinion, the authors incorrectly state the units of the rate of transpiration (E) - it should be mmol (not moles) H₂O m^-2 s^-1.
7. Lines 191-193: On the basis of which results the authors declare that „The effective temperature of 20 °C appeared to have a higher ratio of opened photosystem II and higher photochemical efficiency for butterhead lettuce than 15 °C, 25 °C, and 30 °C.“?
8. At what time of the day (photoperiod) were the leaves harvest to determine „biochemical attributes“? Due to their variability during the day, this should be stated in Materials and Methods.
9. Measuring parameters (light intensity, CO₂ concentration, temperature) of the measurement of photosynthetic parameters should be added to the text of Materials and Methods. Was the same light intensity (at which the plants were grown) used for the measurement or one light intensity (what?) for all variations of growing intensity? Similar to biochemical attributes, the day-time of the measurement should be stated.

Reviewer 2 Report

In this paper the authors analyzed the effect of light intensity, photoperiod and day/night temperature on the growth, quality, and photosynthetic attributes of butterhead lettuce. In my opinion, although explored thoroughly in the past, this still represents a very interesting topic; the manuscript however shows some weaknesses which require a further review and a careful revision through the text. Main concerns refer to the statistic and the presentation of results and the experimental design. Follow a line by line comment:

Abstract:

In lines 17-18 you said that “Highest growth, biochemical and physiological attributes of lettuce were obtained either at 14 h.d-1/250 μmol.m-2.s-1 PPFD or at 17 h.d-1/200 μmol.m-2.s-1 PPFD” however in lines 25-28 is written “Although  our data showed that higher light intensity, increased photoperiod, and day/night temperature  (20/20 °C) increased the growth and quality attributes of ‘butterhead’ lettuce” This might be confunding since 200-250 ppfd are not the highest LI and 14hd is not the highest photoperiod. Please avoid confusion at the beginning of the paper.

Introduction:

Line 61: you can avoid the full stop between umol m2 and s-1. Check throughout the text.

Line 62: “h.d-1” same comment as above.

Lines 74-76: these are just repletion of the lines above (70-73), please summarize.

Line 77: What do you mean by “Over a variable time period"?

Line 84: “horticultural crops” can you mention some?

Lines 90-91: Why?

Line 108: I would avoid “very”

Line 109: it's more correct to say "in lieu of". this use at the beginning of a sentence doesn't sound right.

 

Results:

This section needs most of the work. If I understood correctly, in the graphs and tables the letters of significance are comparisons among the different treatments; however, you often comment about highest/lowest overall values. If so, please add some other tables/graphs showing those statistics (anova with interaction between factors) even in the supplemental materials, otherwise it results very difficult to follow.

Lines 117-119: In all values? why don't you report the level of significancy for each parameter in the table? You can add the p value with asterisks or number in the table.

Line 121: it seems to me that there is no statistical significatively among parameter at 11hd-1

Lines 122-123: yes, but this is not true for all parameters, please better specify.

Line 126: Again, this is not true for all parameters and what it struck me most is that there is no decrease from 250 to 300 but instead there is no statistical difference between 250 and 300.

Line 128-129: is this statistically significant? it is not showed in the table.

Line 133-134: I do not understand the statistics in Table 1, if you want to comment on highest and lowest values between all parameters you should apply and show another kind of statistics. please clarify it through the text following the indication above

Lines 7-8: are you sure about it?? from the letters in the graph there is no statistical differences between data.

Lines 11-12: so if it was not-significantly it did not increase.

Lines 13-14: please comment the results based on the graph and on the statistics you actually show.

Line 21: This is not true in the 11hd-1 treatment

Lines 32-33: this is not really true, the treatment 17h resulted lower or not significant compared to the treatment 14h at certain ppfd.

Line 58: add a space between showed and highest.

In figure 2: the legend on the graph should be inside the external square

Lines 84-86: This should go in the m&m section. You can maybe divide the experiments in number 1 and 2 and assign different labels to clarify what you did.

Line 127: in the graph you reported 75% and 10%. Please uniforms.

Figure 4: it is not necessary to report again in square the name of the graph, the y axes it is pretty clear

 

 Discussion:

Line 215: why do you think such a different in LI from 200 to 800?

Lines 221-222: can you better explain this concept please.

Lines 241-242: usually or over here? please specify.

Lines 292-293: have you as well measured the uptake of these nutrients ?

Line 315: have you performed a photosynthetic light curve to actually measure the light saturation point? this could be helpful

 

Lines 342-343: why?

Line 346: Why don’t you have measured some stomata morphological traits?

 

M&M:

Line 352: why did you use light for germination?

Line 353: it seems odd that you haven't use LED lights. These kinds of lamps provide more heat to the plants. why this choice?

Lines 359-360: why? wasn't it more correct to measure it at the same height of the plant? to understand how much light really arrived over there?

Lines 364-365: So the temperature day/night were the same in all the light treatments?

Line 392: Please explain the acronym

Line 429: what do you mean by data? which kind of measurements?

Reviewer 3 Report

Evaluation of effects of photoperiod, light intensity, and temperature on the growth, quality, and photosynthetic attributes of butterhead lettuce (Lactuca sativa L. cv. Gustav) under glasshouse conditions

The manuscript is aimed to investigate effect of photoperiod, light intensity and day/night temperatures to decipher optimal growth conditions in butterhead lettuce under glasshouse conditions. The investigation is very interesting, giving the new insight into response of butterhead lettuce in terms of growth as well as physiological and biochemical parameters. The manuscript was planned to be designed to provide valuable information for lettuce growers to gain the best yield however, the authors failed to do so. The hypothesis is missing and it should be clearly stated it he introduction.

The statistical analyses needs to be checked and corrected. The tables and figures are not correct and does not follow the results and vice versa, authors needs to pay attention in describing the results. The same letters means that there is no statistical differences between compared groups. It also needs to be stated in M&M what was compared to what, and what is the number of replicates, biological and technical.

This is comprehensive study on effect of light intensity, photoperiod as well as day and night temperature on different physiological and morphological parameters butterhead lettuce in greenhouse. However, the abstract is misleading and the experimental settings were also ambiguous. As I read the abstract I was into impression that authors did all the PP, LI and temperature combinations. Only when one start reading the results, one can figure it out that only one PP/LI combination was used to investigate influence of temperature and from this one cannot be sure why this combination was even used. Therefore, main concern is the experimental setup. With this in mind, whole conclusion (as well as the abstract and the aim) is misleading.

The title is too long!

Why those photoperiod combinations was used? It is very unusual. It needs to be explained and rationale! Also, why so many temp combinations was used? And why those? Is this usual combinations for lettuce growers? Please explain and rationale in the MS!

Here are also some issues in the pdf (I started to correct, but there is too many errors in Results, and consequently in the Discussion) that authors have to consider and to correct before it could be accepted for publication. Please find the pdf file attached for some of the comments and suggestions that needs to be incorporated and corrected. Authors should carefully read their results according to statistics and discuss their real results. You cannot state that only one of the treatments is the most beneficial since results are showing different story!

Sincerely

Comments for author File: Comments.pdf