Organic Substrates Differentially Affect Growth and Macronutrient Concentrations of Lulo (Solanum quitoense Lam.) Seedlings

Round 1

Reviewer 1 Report

This manuscript tested the effect of varying percentages (v/v) of peatmoss and compost (60/40, T1; 12 40/60, T2; 20/80, T3, respectively) on the nutrient status and growth of lulo (Solanum quitoense Lam.) 13 plantlets. Overall, the subject certainly falls within the general scope of Horticulturae journal. However, I have some concerns about the work presented in the MS.

 

Major concerns:

1. Abstract: This section is completely different than the Introduction section. The main findings with important opinions are acceptable. The authors need to consider these points in the revision stage. The mathematical terms need to be added.

2. The study lacks a specific rational and novelty, and it should clear the significance of the study. The written of the Introduction is not enough.

3. It is suggest to rewrite the "objectives" of the MS in the last paragraph of Introduction. It was not suitable to list the findings of the results, but to give out the scientific HYPOTHESIS and the OBJECTIVES.

4. Some important information were missing in METHODS. For instance, how many replications for each treatment? .......

5. In the Results and Discussions part, the authors only presented the experimental results simply. More detailed mechanism analyses are needed to explain

6. The Conclusions section should be considerably improved. In addition, the authors are advised to clearly summarize the actions are taken and main results, as well as explain the significance of their results using quantitative reasoning. The originality and innovations of the study should be clarified and highlighted.

7. Please double check the annotation of statistical analysis results and also check the location of the letters in each bar.

Author Response

Manuscript ID: horticulturae-1995927

Organic Substrates Differentially Affect Growth and Macronutrient Concentrations of Lulo (Solanum quitoense Lam.) Seedlings

Libia Iris Trejo-Téllez¹, Fernando Carlos Gómez-Merino¹*, J. Cruz García-Albarado², and María G. Peralta-Sánchez¹

Reply to Reviewer 1

1. Abstract: This section is completely different than the Introduction section. The main findings with important opinions are acceptable. The authors need to consider these points in the revision stage. The mathematical terms need to be added.

Agreed. We added some data and edited the final version of this section. According to the “Instructions for authors” of the journal, the current version of the Abstract has an extension of 200 words.

2. The study lacks a specific rational and novelty, and it should clear the significance of the study. The written of the Introduction is not enough.

Agreed. The Introduction was revised and edited. Novel information regarding the topic of research was added. Recent references were included in the revised version.

3. It is suggested to rewrite the "objectives" of the MS in the last paragraph of Introduction. It was not suitable to list the findings of the results, but to give out the scientific HYPOTHESIS and the OBJECTIVES.

Agreed. We revised and edited the Objectives in the revised version, Furthermore, derived from our Objectives, we clearly developed the Hypothesis of the study.

4. Some important information were missing in METHODS. For instance, how many replications for each treatment?

Agreed. We reviewed and edited the Methods in the revised version of our manuscript. To be more explicit, we included an illustrative diagram as Figure 1, with the following legend:

Figure 1. Randomized distribution of treatments and repetitions in the experiment designed to test the effect of different peatmoss/compost combinations on growth and macronutrient concentrations of lulo (Solanum quitoense Lam.) seedlings under greenhouse conditions. Treatments are as follows (percentage of peatmoss/compost, v/v): T1: 60/40; T2: 40/60; T3: 20/80.

5. In the Results and Discussions part, the authors only presented the experimental results simply. More detailed mechanism analyses are needed to explain.

Agreed. We reviewed and edited this section in the revised version of our manuscript. We included novel explanations of the phenomena observed, based on recent literature published in high quality journals.

6. The Conclusions section should be considerably improved. In addition, the authors are advised to clearly summarize the actions are taken and main results, as well as explain the significance of their results using quantitative reasoning. The originality and innovations of the study should be clarified and highlighted.

Agreed. The Conclusions were reviewed and edited in the revised version. The The originality and novelty of the study was highlighted.

7. Please double check the annotation of statistical analysis results and also check the location of the letters in each bar.

Agreed. Data were re-analyzed, and new tables and figures were included. The letters in each bar were doble checked.

Author Response File: Author Response.docx

Reviewer 2 Report

Manuscript presents well-rounded study, reporting innovative advances that further knowledge about a topic of importance. The aim is clearly stated. Introduction provides sufficient background information to enable readers to better understand the problem. Conclusions clearly support by the results. Some comments are indicated in the text (PDF)

Comments for author File: Comments.pdf

Author Response

Manuscript ID: horticulturae-1995927

Organic Substrates Differentially Affect Growth and Macronutrient Concentrations of Lulo (Solanum quitoense Lam.) Seedlings

Libia Iris Trejo-Téllez¹, Fernando Carlos Gómez-Merino¹*, J. Cruz García-Albarado², and María G. Peralta-Sánchez¹

Reply to Reviewer 2

Agreed. Dimensions of the greenhouse were included in the revised version of the manuscript, and the letter p indicating the value of probability was written in italics throughout the document.  

Author Response File: Author Response.docx

Reviewer 3 Report

The current manuscript presents some interesting results related to substrate quality and growth/nutrient parameters of Solanum quitoense, even though this seems to be a confirmatory type of study rather than presenting any novel assessment approach. It should be of interest to those involved with the commercial exploitation of this species and could be of general interest to readers of the journal.

 

My main concern is in relation to data treatment and analyses. The authors state in the Methods section they used ANOVA to test the associations between treatments and response variables, but they do not clarify anywhere how the pseudoreplication was dealt with. In my understanding, the experiment resembles a block design within a greenhouse, which suggests treatment units are pseudoreplicated (i.e., under the same type of conditions, which makes any expectation of independence of errors between units unreasonable). Would a linear mixed effects model be more appropriate to deal with this issue than ANOVA? If not, the authors should make the case as to why they chose ANOVA. In addition, it is difficult to judge the adequacy of the numerical modelling considering the degrees of freedom are not presented anywhere. The experimental and data analyses subsections in the Methods section need further clarifications (as per my comments below) and I believe the authors need to address these issues before this can be considered for publication.

 

I make further comments below by page and line number to help improve the quality of the manuscript.

 

Abstract

The Abstract is somewhat vague. References are made to ‘growth attributes’ and ‘nutrient concentrations’, but we do not know what these are at this stage. That should be made clearer. It would also be helpful to state where the study took place and add one or two sentences about the experimental set up.

 

Introduction

The link between substrate quality and plant growth/nutrient status was not made convincingly enough to motivate the study (P2, L56-57). I’d suggest expanding on this to better justify the need for this type of research.

 

Methods

P2, L69-73: the experimental design requires more explanation. Was this a randomised block design? What were the sizes of the individual treatment blocks? How were they spaced out between them? The authors state they had four replicates and three treatments, which should give 12 experimental units. Where do the 128 units come from? A schematic diagram to illustrate the experiment would be helpful.

P2, L74-79 & P3, L102-115: these seem unnecessary since the figures are already given in the tables; these paragraphs mostly read like a Results/Discussion section rather than Methods. I’d suggest integrating these with the discussion of results (i.e., how do these substrate parameters fit within the study findings)?

Table 1 & Table 2: are these mean values measured by the authors? If so, please provide a measure of variability around them (e.g., standard deviation). The same applies to numerical results presented in the main text in the Results section.

P4, L156: please specify what these growth parameters and mineral nutrients are. There should also be a statement as to what the main objective of this analysis is (i.e., to test associations between the experimental treatments and the plant growth/nutrient variables).

P4, L161-164: what was the correlation method used? If a parametric test, were the assumptions of such test met (e.g., data distribution)? Plant trait data, including plant height, tend to be log-transformed prior to numerical analyses. Were these data transformed in anyway? If not, why not? I suppose there is an argument not to transform them since all measurements came from the same species, but that should be made clear. Also, these variables were not introduced anywhere in the text prior to this point; how were they measured? Essentially, the data analyses sections need further explanations.

 

Results and Discussion

Figure 1: I’d suggest referring to these as bars, not columns. The same applies to Figure 2.

P6, L193: is it one standard deviation? Please clarify (also in Figure 2). In addition, the type of numerical analyses performed to estimate p values should probably be stated in the figure caption (also in Figure 2).

P6, L200-202: this sentence is poorly phrased. Please rewrite.

P7, L229-232: this is not very clear. Do the plants regulate S uptake, or do S levels have to be kept lower by farmers? Please clarify. Also, are the authors concluding from their results that P and S levels applied in this study were found to be enough for plant growth? That’s not clear either. I’d suggest rewriting these sentences.

P7, L234-257: it seems odd the discussion of the results come before the results themselves. I’d suggest presenting the results for plant growth first (i.e., what is shown in Figure 2), to then discuss them.

P7, L261: I’d suggest ‘low pH’ rather than ‘acidic pH’.

P7, L273-278: it seems the results for root variables are presented here but not properly discussed. Some inference is made to soil EC, but the links between them are not made clear. Please rewrite.

P7, L275: 60 cm?

P7-8, L279-290: this is somewhat confusing. The authors seem to reintroduce the results for plant growth, which were apparently introduced at the beginning of this subsection. It’s odd they are split across different parts of the text. This may be a result of combining the Results and Discussion sections together. I’d ask the authors to reconsider this approach. It might make the text clearer if the results are presented first within clear subheadings, and then discussed in a separate section under similar subheadings.

P8, L301-302: this seems unnecessary. The tool used for analyses should be introduced in the Methods section.

P8, L304-305: why more efficient? Because it correlates to total biomass? Please explain.

P8, L306: what is the meaning of ‘stimulated’ here? Were they positively correlated? Please clarify.

P8, L307: recorded elsewhere?

P8, L315-320: this paragraph seems to attempt to discuss the pros and cons of the high morphological/physiological variability in this species, but not convincingly. Why is that an advantage for future breeding programmes? These arguments need some further explanations.

Table 4: the type of correlation analyses should probably be stated in the table caption.

 

Conclusions

P9, L327-343: this seems to mostly repeat the results presented previously. Do these results have any implications for the large-scale farming of this species? Are they surprising/revealing in any way that should change how this species is currently cultivated? Do they mean anything in terms of the sustainability of the commercial exploitation of this species (i.e., are there any general environmental implications associated with the peatmoss/compost mixture recommended as optimal)? I believe a few short sentences addressing these points would be more interesting than simply repeating what was presented earlier.

Author Response

Manuscript ID: horticulturae-1995927

Organic Substrates Differentially Affect Growth and Macronutrient Concentrations of Lulo (Solanum quitoense Lam.) Seedlings

Libia Iris Trejo-Téllez¹, Fernando Carlos Gómez-Merino¹*, J. Cruz García-Albarado², and María G. Peralta-Sánchez¹

Reply to Reviewer 3

My main concern is in relation to data treatment and analyses. The authors state in the Methods section they used ANOVA to test the associations between treatments and response variables, but they do not clarify anywhere how the pseudoreplication was dealt with. In my understanding, the experiment resembles a block design within a greenhouse, which suggests treatment units are pseudoreplicated (i.e., under the same type of conditions, which makes any expectation of independence of errors between units unreasonable). Would a linear mixed effects model be more appropriate to deal with this issue than ANOVA? If not, the authors should make the case as to why they chose ANOVA. In addition, it is difficult to judge the adequacy of the numerical modelling considering the degrees of freedom are not presented anywhere. The experimental and data analyses subsections in the Methods section need further clarifications (as per my comments below) and I believe the authors need to address these issues before this can be considered for publication.

Agreed. Data were re-analyzed, and we performed the test for normality and homogeneity, as described in the revised version re-submitted. Data that did not comply with the assumptions of normality and homogeneity were analyzed with tests designed for non-parametric data. Accordingly, new figures and tables resulting from such analyses were included in the revised version of the manuscript.

I make further comments below by page and line number to help improve the quality of the manuscript.

Abstract

The Abstract is somewhat vague. References are made to ‘growth attributes’ and ‘nutrient concentrations’, but we do not know what these are at this stage. That should be made clearer. It would also be helpful to state where the study took place and add one or two sentences about the experimental set up.

Agreed. The abstract was revised and edited in the revised version.

Introduction

The link between substrate quality and plant growth/nutrient status was not made convincingly enough to motivate the study (P2, L56-57). I’d suggest expanding on this to better justify the need for this type of research.

Agreed. The information suggested was included in the revised version of the manuscript.

Methods

P2, L69-73: the experimental design requires more explanation. Was this a randomised block design? What were the sizes of the individual treatment blocks? How were they spaced out between them? The authors state they had four replicates and three treatments, which should give 12 experimental units. Where do the 128 units come from? A schematic diagram to illustrate the experiment would be helpful.

Agreed. All this data was included in the revised version of the manuscript re-submitted.

P2, L74-79 & P3, L102-115: these seem unnecessary since the figures are already given in the tables; these paragraphs mostly read like a Results/Discussion section rather than Methods. I’d suggest integrating these with the discussion of results (i.e., how do these substrate parameters fit within the study findings)?

Agreed. There paragraphs were moved to the Results and Discussion section.

Table 1 & Table 2: are these mean values measured by the authors? If so, please provide a measure of variability around them (e.g., standard deviation). The same applies to numerical results presented in the main text in the Results section.

Agreed. In the revised version, Tables 1 and 2 include SD of three samples.

P4, L156: please specify what these growth parameters and mineral nutrients are. There should also be a statement as to what the main objective of this analysis is (i.e., to test associations between the experimental treatments and the plant growth/nutrient variables).

The analyses of variance were conducted independently for each growth and nutritional variable, with the objective of evaluating the effects among treatments (substrates).

P4, L161-164: what was the correlation method used? If a parametric test, were the assumptions of such test met (e.g., data distribution)? Plant trait data, including plant height, tend to be log-transformed prior to numerical analyses. Were these data transformed in anyway? If not, why not? I suppose there is an argument not to transform them since all measurements came from the same species, but that should be made clear. Also, these variables were not introduced anywhere in the text prior to this point; how were they measured? Essentially, the data analyses sections need further explanations.

Agreed. The Pearson correlation test was used to perform this analysis. The variables that fulfilled assumptions of normality and homogeneity were evaluated with analysis of variance. Those that did not comply were analyzed with a non-parametric tool (Wilcoxon's rank summation tests).

Results and Discussion

Figure 1: I’d suggest referring to these as bars, not columns. The same applies to Figure 2.

Agreed. Figures and tables were re-designed/edited to express the results in a better way.

P6, L193: is it one standard deviation? Please clarify (also in Figure 2). In addition, the type of numerical analyses performed to estimate p values should probably be stated in the figure caption (also in Figure 2).

Agreed. In the revised version, we included the p-value of all results both in tables and figures.

P6, L200-202: this sentence is poorly phrased. Please rewrite.

Since no statistical differences were observed among treatments for this variable, we eliminated this sentence from the revised version.

P7, L229-232: this is not very clear. Do the plants regulate S uptake, or do S levels have to be kept lower by farmers? Please clarify. Also, are the authors concluding from their results that P and S levels applied in this study were found to be enough for plant growth? That’s not clear either. I’d suggest rewriting these sentences.

Agreed. We revised and edited this sentence in the revised version.

P7, L234-257: it seems odd the discussion of the results come before the results themselves. I’d suggest presenting the results for plant growth first (i.e., what is shown in Figure 2), to then discuss them.

Agreed. We revised and edited this sentence in the revised version.

P7, L261: I’d suggest ‘low pH’ rather than ‘acidic pH’.

Agreed. The expression “acidic pH” was replaced by “low pH” in the revised version.

P7, L273-278: it seems the results for root variables are presented here but not properly discussed. Some inference is made to soil EC, but the links between them are not made clear. Please rewrite.

Agreed. This paragraph was revised and edited in the revised version.

P7, L275: 60 cm?

We have revised and corrected accordingly. The right unit is percentage (%), not centimeter (cm)

P7-8, L279-290: this is somewhat confusing. The authors seem to reintroduce the results for plant growth, which were apparently introduced at the beginning of this subsection. It’s odd they are split across different parts of the text. This may be a result of combining the Results and Discussion sections together. I’d ask the authors to reconsider this approach. It might make the text clearer if the results are presented first within clear subheadings, and then discussed in a separate section under similar subheadings.

Agreed. This paragraph was revised and edited in the revised version.

P8, L301-302: this seems unnecessary. The tool used for analyses should be introduced in the Methods section.

Agreed. This paragraph was revised and edited in the revised version.

P8, L304-305: why more efficient? Because it correlates to total biomass? Please explain.

Agreed. This paragraph was revised and edited in the revised version.

 

P8, L306: what is the meaning of ‘stimulated’ here? Were they positively correlated? Please clarify.

This sentence was deleted from the revised version.

P8, L307: recorded elsewhere?

Yes, the corresponding reference is [36]

P8, L315-320: this paragraph seems to attempt to discuss the pros and cons of the high morphological/physiological variability in this species, but not convincingly. Why is that an advantage for future breeding programmes? These arguments need some further explanations.

Table 4: the type of correlation analyses should probably be stated in the table caption.

Agreed. This paragraph was revised and edited in the revised version. A new reference was included.

Conclusions

P9, L327-343: this seems to mostly repeat the results presented previously. Do these results have any implications for the large-scale farming of this species? Are they surprising/revealing in any way that should change how this species is currently cultivated? Do they mean anything in terms of the sustainability of the commercial exploitation of this species (i.e., are there any general environmental implications associated with the peatmoss/compost mixture recommended as optimal)? I believe a few short sentences addressing these points would be more interesting than simply repeating what was presented earlier.

Agreed. This paragraph was revised and edited in the revised version. However, we kept most of the content previously written, since we consider that it is needed to keep in mind the main findings of our study.

Author Response File: Author Response.docx