Effect of White LED Light on the Growth of Apple Seedlings in Controlled Environment System

Round 1

Reviewer 1 Report

In this study, Choi et. al. studied the effect of White LED Light Intensity on the Growth of Apple Rootstock Seedlings. In my opinion, the data is weak, and the study lacks a clear hypothesis. The manuscript is written badly, and overall data representation could have been better. The controls are missing in every figures. My other comments are below:

• The language of the manuscript must be improved. There are many grammatical errors throughout the manuscript including title and abstract. There are many places where the author's message is not clear due to improper phrasing and English language.
• In the beginning of the abstract, explain the rationale to use the LED lights.
• Introduction: Explain the effect of LED light in other plants’ growth and development
• Citation of Table 1 in the text is missing.
• I was wondering why preliminary treatment was given if they grow well on 25°C and what was logic for doing this experiment it is also unclear.
• Please mention the scale bar figures 1A and 2B.
• What was the size of seedling in the beginning? And what was the size of seedling of 3 leaves stage.
• Instead of plant, use shoot height in the figure 1 as it is actually shoot which was measured.
• Authors mentioned that they used plants of 3.8 cm (line 93) for the temp treatment but from the fig 1B it seems that height of plants is not even 3.8 cm. I would suggest authors to include the data of plant height (before the treatment) in the figure. Please interpret the results (line 141-147) by taking pretreatment control conditions.
• Fig 5B: I would like to see the standard error instead of standard deviation.
• The statements of the Lines 146-155 are not justifiable with these references (19, 20, 21). High temp and ethylene never promote shoot elongation and ref no. 19, 20 are completely different what authors mentioned in the above lines.
• Similarly, the controls for the no. of leaves and leaf area are also missing in all figures. I would like to suggest authors to rewrite the results and discussion wrt to control not with temp treatment or LED treatment samples themselves.

Author Response

Thank you for your review about my manuscript. I edited my manuscript including your review point.

Author Response File: Author Response.docx

Reviewer 2 Report

General comments

I strongly encourage the authors to correct grammar/syntax mistakes in the text. Please check the text carefully.

Specific comments

Abstract

I suggest the authors to rewrite the abstract. Please take into consideration my comments for the results.

Introduction

L51. “….for activities of plant”. Do you mean plant physiology functions?

L65, L68. Please replace “in-vitro” with “in vitro” (check the text).

Are there any references about the effect of light the growth of seedlings propagated in vitro?

Materials and Methods

L74. Do you mean 72 holes in each tray? Please describe the oasis block.

L75. Please use space between number and unit, as in L74 (please check the text).

L85-88. Did the authors use two replicates with twenty plants each? In this case the authors can not do the statistical analysis of their results.

L89. Please refer the pH of the nutrient solution. Do the authors mean meq L^-1?

L94. Please see line 74.

L95. Please provide more details about the peat moss (pH, nutrients, trademark).

L123. We always measure the dry weight of tissues until constant weight. Was the weight of the tissue constant after 48 hours?

L126. In my opinion the number of plants per treatment is small. How did the authors choose the number of plants per treatment?

Results-Discussion

L134. The survival rate of seedlings seems to be equal in treatments T1 (38 plants) and T2 (39 plants). In addition, the statistical analysis is missing from the table 2. How can we conclude that treatment T2 has higher seedling survival?

L155. Do the authors mean stem elongation?

L160 (Figure 1). The authors show a statistical analysis with n=5, but they had 40 plants. Please define. Why did the authors use only 5 plants for these measurements? Please see this comment and the comment for L134.

L172 (Table 3). As in line 160. Why did the authors use only 5 plants (the number is small)? Why did the authors use the Duncan’s multiple range test for the comparison of only three treatments? Please explain.

L174-178. In figure 2A, the reader can not see that there is a statistically significant difference between=n L3 and L4. Even after 30 days the standard deviation is very high (probably duo to the small number of plants-replicates per treatment), and the difference between L3, L2 and L4 seems not to be statistically significant. The authors must correct carefully the presentation of the results in the text (here and elsewhere in the text, e.g. number of leaves). In figure 2D, L2 does not differ significantly from L5 but it differs significantly from L3 (please see standard deviations and line 202). Is it correct?

 In my opinion, the small number (5) of replicates-plants per treatment is a serious limitation of this work. In any case, the authors must refer that while they are discussing their results.

L208 (Table 4). Shoot fresh weight: Please check. Are the letters correct?

L222. Please correct. The root dry weight per plant in L3-treated seedlings is not higher that than in L2-treated seedlings.

L231-232. Please correct. The rate of photosynthesis in L3-treated seedlings was not statistically significant higher compared with L2- and L1- treated ones.

I encourage the authors to rewrite the Results – Discussion section, present the results carefully in the text and discuss them properly (the discussion needs to be improved). In my opinion, the small number (5) of replicates-plants per treatment is a serious limitation of this work. In any case, the authors must take into consideration this limitation while they are discussing their results and draw their conclusion.

L244. Please separate the title of the table from the text.

References

L309. Please replace “lett.” with “Lett.”

L369. Journal title must be in italics.

Author Response

Thank you for your review about my manuscript. I edited my manuscript including your review points.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Although authors improved the manuscript substantially, however manuscript still needs improvement in English language. 

Author Response

Thank you for your second review. We edited our manuscript considering your review pont.

Author Response File: Author Response.docx

Reviewer 2 Report

The authors did a good effort to improve their manuscript.

However, some mistakes must be corrected.

1. Please correct some syntax/grammar mistakes.
2. Point 7 of author’s response. You cannot carry out the analysis of variance with two replicates. In fact, the authors used 40 replicates (n=40, please see what you refer in table 1). In such a case, I suggest writing in the materials and methods section that you used 20 seedlings (replicates) and the experiment was conducted twice. The values in table 1 are the means of 40 replicates.
3. Point 12 of author’s response. The number of plants is small. The authors considered this limitation while they are discussing their results. Please allow me a comment on your response. We always avoid bias in data analysis of experiments and select plants randomly (except if we have decided from the begging the border plants).
4. Point 16 of author’s response. Please allow me a comment on your response. The comparison of more than two treatments (multiple comparison) always involves the analysis of variance (ANOVA). The results will tell you if there is a difference in means. Thus, when the F test is significant (e.g. at P = 0.05). there are procedures for testing multiple comparisons in analysis of variance and means can be separated by the application of different tests, i.e. Duncan’s test, Least Significant Difference (L.S.D.) test, Tukey's HSD (honestly significant difference) test, Scheffé's test etc. Duncan’s Multiple Range test (DMRT) is a post hoc test to measure specific differences between pairs of means and it is very useful for the comparison of more than three treatments (e.g. five or six), in order to guard against the possibility of marking differences significant when they are not.
5. Point 17 of author’s response. In my opinion the standard deviations are more useful than the standard errors. However, the authors could help the reader to see the statistical differences by changing the scale on the axis of ψ, e.g. start from 3 to 12 in fig 2A and start from 10 to 20 in fig 2C, and thus increase the distance between the lines without changing the figure size.
6. Line 108. Please rewrite the sentence.
7. Line 248 (Table 4). The table is not presented well in the text.

Author Response

Thank you for your second review. We edited our manuscript considering your review points.

Author Response File: Author Response.docx