Review Reports - Could an Early Treatment with GA and BA Impact Prolonged Cold Storage and Shelf Life of Apricot?

Round 1

Reviewer 1 Report

The manuscript title “Could an early treatment with GA and BA impact prolonged cold storage and shelf life of apricot?” has major concerns. This MS need significant changes and improvements.

My detail comments for authors are as follows:

1- Please add some background (scientific worth) of this study (2-3 lines) in the abstract.

2- Line: 19-20. “For postharvest experiment were used apricots in stage of commercial of ripeness (IAD 0.4-0.8)”. What authors want to say? Please rewrite this sentence.

3- Line 31: “intensification of apricot production such as, for example, use of different rootstocks”. Use such as or for example…

4- Line 55: ‘[15, 16, 17, 18, 19]’. Just write [15-19].

5- In introduction authors didn’t give any background of 6-benzyladenine (BA). What are different roles and function of BA in plants and their effect on shelf life in fruits? Authors must have to add BA background in the introduction.

6- Complete methods of phenolic contents, flavonoid and carotenoid contents are missing…. Which standard you have used to measure these metabolites????

7- How you have expressed the phenolic contents, flavonoid and carotenoid contents and others??? Such as mg/mL or other units?? Please add this in table 1.

8- Tables 1 and 2: please write data 62.2 not like this 62,2… don’t use comma, remove all the comma’s from table 1 and 2.

Author Response

Responses to the Reviwer 1, horticulturae-2066492

The authors wish to thank the Editor and Reviewers for the useful and highly contributing inputs which, in our opinion, improved our manuscript. We studied carefully all the remarks provided by the Reviewers and in the following lines You can find the our considerations and responses. In addition, all the changes that we made in the manuscript can be tracked through an option: “Track changes”.

Please add some background (scientific worth) of this study (2-3 lines) in the abstract.
Thank you for comment. Sentence: “Application of PGRs in apricot orchards is common practice with goals to improve yield and/or quality at harvest, however question whether such treatment alters postharvest properties is rarely answered. “ is added at the beginning of the abstract.

Line: 19-20. “For postharvest experiment were used apricots in stage of commercial of ripeness (IAD 0.4-0.8)”. What authors want to say? Please rewrite this sentence.
The sentence:

“For postharvest experiment were used apricots in stage of commercial of ripeness (IAD 0.4-0.8)”

was rewritten and it states as follows:

“For postharvest experiment were used apricots in stage of commercial of ripeness”.

Explanation how apricot fruit in similar ripening stage ensured by using DA meter was provided in material and methods chapter with sentence:

“In order to determine effects on apricot fruits at harvest and after the prolonged storage period, fruit in commercial ripeness (Iad 0.4-0.8), determined by DA-meter (TR Turoni, Bologna, Italy) were harvested [29].”

And appropriately cited reference

Kovač, R.; Kevrešan, Ž.; Mastilović, J., Magazin, N.; Milić, M.; Milović, M.; Bajić, A.; Kalajdžić, J.; Barać, G.; Keserović, Z. IAD values of apricot (Prunus armeniaca L.) at harvest in relation to fruit quality and sensory properties during cold storage and shelf life. N. Z. J. Crop Hortic. Sci. 2022, 1-18.

Line 31: “intensification of apricot production such as, for example, use of different rootstocks”. Use such as or for example…
Line 31 was rewritten and it states: With the goal to improve apricot production many contemporary systems and techniques were applied in orchards resulting in intensification of apricot production, such as different rootstocks, interstocks, increase of tree density, irrigation, pruning, thinning, fertilization, grassing, mulching and weed control [1-4].

Line 55: ‘[15, 16, 17, 18, 19]’. Just write [15-19].
Corrected as suggested throughout whole manuscript.

In introduction authors didn’t give any background of 6-benzyladenine (BA). What are different roles and function of BA in plants and their effect on shelf life in fruits? Authors must have to add BA background in the introduction.
Thank You for the suggestion. In the following paragraph the authors briefly tried to emphasize the roles and significance of BA on fruit development.

“In respect to BA, this plant hormone belongs to the group of cytokinins, and is well-known for their role in plant growth and development, while the studies reflecting on its effect on fruit development were mostly focused to climacteric fruits, where it could slow down ripening, possibly through suppressing biosynthesis of ethylene [13]. It was previously proven that BA has an effect on fruit set, its development as well as fruit shape. Namely, the combination of gibberellins A4 and A7 with the cytokinin BA improved fruit appearance in Red Delicious apples. The success resulted in its different uses on a wide variety of crops [15].”

Paragraph was added in introduction chapter, after sentence “Cytokinin applied at pit hardening stage had effect on fruit physiological, organoleptic and phytochemical properties [22].” (Line 59 in original manuscript)

Complete methods of phenolic contents, flavonoid and carotenoid contents are missing…. Which standard you have used to measure these metabolites????
We agree with the suggestion that the description of the performed methods were quite short, but the background for this lies in the fact that the analyses of phenolis, flavonoid and carotenoid contents were performed according to the standard and previously described methods, thus the relevant references were given in the text. Another rationale for this was that the authors tried to avoid burdening already long enough manuscript with unnecessary details. All necessary literature was cited in sentence (lines: 126-127): Carotenoid content was analyzed according to Costache et al. [30], while phenolic and flavonoids were extracted according to [31], phenol content was determined ac-cording to Folin-Ciocalteu method [32], while for flavonoids procedure by Pękal and Pyrzynska [33] was used.

In order to make methods more clear, after sentence which refer methods to literature sentence was added:

Brief explanation of used methods were described earlier [6, 27, 29]

However, if the Reviewer 1 still finds it necessary, the authors would add all the details regarding the named methods to the manuscript, although this can be found in the respective references.

How you have expressed the phenolic contents, flavonoid and carotenoid contents and others??? Such as mg/mL or other units?? Please add this in table 1.
We are very sorry for this overlook. All units were added to Table 1. Authors are very thankful for pointing out the lack of units!

Tables 1 and 2: please write data 62.2 not like this 62,2… don’t use comma, remove all the comma’s from table 1 and 2.
Again, thank you for noticing. Corrections were made as suggested

Author Response File: Author Response.docx

Reviewer 2 Report

The main purpose of this work was to study the impact of gibberellic acid (GA3) and 6-benzyladenine (BA) on physical characteristics and composition of apricot fruit.

This work is well written; clearly and objectively, however, it follows some comments:

In several places in the manuscript, it is necessary to change “tretaed" by “treated”.

In this article, several properties were studied, such as physiological parameters, physicochemical properties, and sensory properties. However, based on these parameters obtained, it was not possible to detect which conditions provide a better storage process of this fruit.

Thus, it is very important that the authors indicate the best treatment, based on the properties obtained, in order to optimize the shelf life of this fruit.

Author Response

Responses to the Reviwer 2, horticulturae-2066492

R2: In several places in the manuscript, it is necessary to change “tretaed" by “treated”.

A: Thank You for noticing this spelling error. It was corrected throughout the manuscript.

R2: In this article, several properties were studied, such as physiological parameters, physicochemical properties, and sensory properties. However, based on these parameters obtained, it was not possible to detect which conditions provide a better storage process of this fruit.

Thus, it is very important that the authors indicate the best treatment, based on the properties obtained, in order to optimize the shelf life of this fruit.

A: This remark – to indicate best treatment based on our result – is what prevented us to publish earlier this manuscript. However discussion with apricot producer gave us an answer how to publish. While discussing problem of application of PGRs, we point out that application does not significantly change overall fruit storage characteristics and that quality of treated fruits does not fall billow quality of control fruit during storage, his answer shed light on our results: “that means that I can apply PGRs, have initial improvement of apricot quality but after storage that quality will diminish leaving me with apricots same quality as non-treated? That is excellent”. So the point of our results and manuscript is not to pick one treatment and state that it is the best one, but rather to point out that application of PGRs did not have negative effect on prolonged postharvest behavior of apricots. Additionally PCA analysis, requested by other reviewer, points out low explanation strength of Factor 2 which is tentatively related to PGRs treatments. In order to make it more clearly, and due to comment of other reviewer, conclusions are rewritten:

As expected, the application of PGR improved most of the quality traits and fruit composition of apricot at harvest. The significant differences between the treated and untreated fruits were observed at harvest in terms of: flesh firmness, color, ethylene production and respiration rate, flavonoids, carotenoid and citric acid content. Prolonged cold storage diminished the initial differences in firmness, respiration rate, flavonoids and carotenoid content, but new differences in fructose, malic and succinic acid content began to appear. Noteworthy, shelf life reduced the difference in citric acid, but the differences in TA, TSS, phenol and flavonoid content were recorded. In terms of sensory properties, the treated and non-treated apricots did not showed differences following the cold storage and shelf life. In addition, despite the observed differences in chemical composition at the end of cold storage, fruit firmness, color as well as sensory traits did not differ between the treated and non-treated fruit. Difference between the treated and non-treated fruit apricots were recorded after shelf life in respect to fruit color, more precisely, treated fruits had lower L*, which made them more dark that control. Still, the recorded fluctuations in chemical composition need another extensive and separate study, which will be focused on the underlying processes that define the ripening, senescence as well as the PGR treatment.

Author Response File: Author Response.docx

Reviewer 3 Report

The subject of the manuscript is relevant and original. It is suitable for the Horticulturae journal. Due to the conducted experiment, the article has practical application, in particular for storage purposes, because the aim of the paper was to examine the influence of gibberellic acid and 6-benzyladenine on the physical properties and composition of apricot fruit after prolonged cold storage (i.e. 21 days) and the shelf life. However, the entire paper requires a number of additions and improvements.

Abstract

It is recommended to add information on the years of the experiment and present more results of the conducted research.

Introduction:

In the introduction, it is necessary to expand on the questions of why?, for what purpose?, and whether such kind of research results will be useful to apricot producers? Please correct that.

Materials and Methods

The research methods need to be sorted out and divided into subchapters. Please refer to the journal editing requirements. I suggest that the manuscript authors considered adding to this part information on the years of the experiment.

Results:

The research results are very general, please expand on them and divide them into subchapters.

Discussion

The discussion should be more extensive. It should be divided into subchapters.

Conclusions

The conclusions are poorly described. Please correct that.

References

The reference choice is suitable, but the editing requirements of the Horticulturae Journal are not followed. Also, please correct reference item no.7: from 2023 to 2022.

Subject to major additions and improvements, as well as another review, the paper can be published in the Horticulturae Journal.

Author Response

Responses to the Reviwer 3, horticulturae-2066492

Abstract

It is recommended to add information on the years of the experiment and present more results of the conducted research.

The changes were already made in the Absract, due to requests of other rewivers:

(I_AD4-0.8) was deleted from abstract.
Following sentence was added at the beginning of the Abstract: “Application of plant growth regulators (PGRs) in apricot orchards is common practice with goals to improve yield and/or quality of fruits at harvest. However, the question of whether such treatment alters postharvest properties is seldom answered.“

In order to add more information about the years of experiment sentence:

“In order to investigate the effects of an early application of plant growth regulators (PGRs) on postharvest changes in apricot fruit, 50 and 100 ppm of benzyladenine (BA) and 200 ppm of gibberellic acid (GA3) were applied when green ovary was surrounded by dying sepal crown, sepals beginning to fall stage”

Was rewritten to:

“The effects of an early application of PGRs on postharvest changes on apricots were investigated on cultivar NS-4, grown on Myrobalan rootstock with blackthorn interstock in 5-year-old orchard. PGR treatments included 50 and 100 ppm of benzyladenine (BA) and 200 ppm of gibberellic acid (GA₃), which were applied when green ovary was surrounded by dying sepal crown, sepals beginning to fall stage.”

Sentence:

“Applied PGRs showed significant effect on color, TA, phenols, flavonoids, fructose, sucrose, malic and succinic acid as well as on tissue breakdown, but exhibited no effect on fruit lightness, firmness, TSS, carotenoids, glucose, majority of sensory properties and browning. The effects of applied PGRs are the most striking at harvest, but their impact decreases during cold storage and shelf life.”

Was rewritten to:

“At harvest, significant differences were observed between treated and untreated fruits regarding flesh firmness, color, ethylene production and respiration rate, flavonoid, carotenoid and citric acid content, while application of BA100 changed TA and TSS. Prolonged cold storage reduced the initial differences in firmness, respiration rate, flavonoids and carotenoid contents, but new differences in fructose, malic and succinic acid content began to appear. Shelf life reduced the difference in citric acid, but differences in TA, TSS, phenol and flavonoid content appeared. There is no difference in sensory properties of treated and non-treated fruit after cold storage and shelf life.”

Introduction:

In the introduction, it is necessary to expand on the questions of why?, for what purpose?, and whether such kind of research results will be useful to apricot producers? Please correct that.

We had in mind "why?" and "for what purpose?" while writing the introduction. Thus, in the first two paragraphs it is stated what was done to improve apricot production (different rootstocks, interstocks, increase of tree density, irrigation, pruning, thinning, fertilization, grassing, mulching and weed control) and also application of PGR. The text also contains an answer to why PRGs were applied and which goals were set.

The purpose of present study, along what is missing in the previous experiments (changes of PGR-treated apricot fruit during cold storage and shelf life) is summarized in the following paragraph:

“However, studies examining an impact of PGR application on fruit quality after cold storage and shelf life are very rare, and mostly based on basic analysis of fruit, such as weight loss and spoilage [25]. Even rarer are the studies examining the relationship of an early PGR treatment with storage and shelf life on fruit quality and chemical composition [26].”

However, the importance of the presented research for manufacturers is not covered. The reason for this is simple - many scientific researches and achievements in this filed are often separated from its real application in practice. Thus, the practical confirmation of scientific results is more than welcome and necessary! Also, there are frequent remarks from reviewers requesting the removal of parts in the manuscript that refer to producers! Being close to the producers and their problems, we are glad that You also recognized the importance of this topic and very happy to have the opportunity to point the significance of our research for the producers.

“Having in mind the frequent use of PGRs in practice today, and a lack of knowledge in terms of their effects on treated fruits, the results of present study provide a glimpse and some interesting answers to the problems associated with PGR application and postharvest behavior of treated fruits. Therefore, this paper is expected to have a significant impact on today’s practice in apricot production”

Materials and Methods

Materials and Methods chapter is now divided on following subchapters:

2.1. Apricot Production and Preharvest Treatments

2.2. Fruit color, texture and weight loss

2.3. Ethylene Production and Respiration Rate

2.4. Chemical analysis

2.5. Sensory evaluation and,

2.5. Statistical Analysis

Considering the years of the experiment, this study is one-year study, which can be concluded from the statistical analysis, thus the year is not a factor in this experiment. To make manuscript more clear, the sentence:

“The trial was set up in a completely randomized design with six single trees used per treatment”

Was rewritten to:

“The one year trial was set up in a completely randomized design with six single trees used per treatment”

Results:

The research results are very general, please expand on them and divide them into subchapters.

Chapter Results was already divided to:

3.1. Weight loss, respiration rate and ethylene production

3.2. Physicochemical properties

3.3. Sensory properties

At the request of another reviewer, a chapter with PCA analysis was added (3.4. PCA analysis), which already presents a significant expansion. This chapter shed new light on the results, through the significance of applied treatments in relation to the time of performed analysis.

In order to further improve results chapter 3.2. Physicochemical properties was divided on subchapters:

3.2.1. Physical properties

3.2.2. Chemical properties

Since performed division of the results improved clarity, all bolded text was reverted to the normal text.

Discussion

The discussion should be more extensive. It should be divided into subchapters.

Due to the complexity of the study and a large volume of collected data, which are very diverse in nature, the authors tried to present the conclusions as comprehensively and precisely as possible, by taking into account all the obtained results. Highlighting some specific details or drawing the conclusions based on some set of the results, will inevitably create a difficulty to follow the main idea, the concept of the work and, finally, to answer the aim of the study.

Also, by discussing each set of the results separately, the paper will lack the connection and interrelation between the set of individual fruit parameters. Since the concept of our discussion chapter was to make connections between parameters, we consider proposed division into subchapters unnecessary.

However, if the reviewer still finds it necessary and more suitable for the paper, we would kindly ask for his suggestion in order to complete the requested task.

As requested by other reviewer comment about PCA is inserted into discussion chapter, making this chapter more extensive.

Conclusions

The conclusions are poorly described. Please correct that.

Having in mind Your comments and comments of other reviewer, conclusions are rewritten:

“As expected, the application of PGR improved most of the quality traits and fruit composition of apricot at harvest. The significant differences between the treated and untreated fruits were observed at harvest in terms of: flesh firmness, color, ethylene production and respiration rate, flavonoids, carotenoid and citric acid content. Prolonged cold storage diminished the initial differences in firmness, respiration rate, flavonoids and carotenoid content, but new differences in fructose, malic and succinic acid content began to appear. Noteworthy, shelf life reduced the difference in citric acid, but the differences in TA, TSS, phenol and flavonoid content were recorded. In terms of sensory properties, the treated and non-treated apricots did not showed differences following the cold storage and shelf life. In addition, despite the observed differences in chemical composition at the end of cold storage, fruit firmness, color as well as sensory traits did not differ between the treated and non-treated fruit. Difference between the treated and non-treated fruit apricots were recorded after shelf life in respect to fruit color, more precisely, treated fruits had lower L*, which made them more dark that control. Still, the recorded fluctuations in chemical composition need another extensive and separate study, which will be focused on the underlying processes that define the ripening, senescence as well as the PGR treatment.”

References

The reference choice is suitable, but the editing requirements of the Horticulturae Journal are not followed. Also, please correct reference item no.7: from 2023 to 2022.

Thank You for noticing this detail. Here is reference 7, cited according to APA style (with DOI):

Rebeaud, S. G., Cioli, L., Cotter, P. Y., & Christen, D. (2023). Cultivar, maturity at harvest and postharvest treatments influence softening of apricots. Postharvest Biology and Technology, 195, 112134. https://doi.org/10.1016/j.postharvbio.2022.112134

We realize that this seems confusing and thereby, incorrect since it is referred as a publication related to the upcoming year, but if You go the the journal’s website (https://www.sciencedirect.com/journal/postharvest-biology-and-technology/vol/195/suppl/C) You will be able to see that volume 195 is related to 2023 and therefore 2023 is the correct year. Namely, recently has become a quite usual practice for journals to firstly publish papers online, and then to schedule them into volumes which will be published in the upcoming period as a hard copy. Since this paper is scheduled for its release in January 2023, this is the reason for the misunderstanding.

As requested, all other references were checked and corrections were made, according to the editing requirements of Horticulturae journal.

Author Response File: Author Response.docx

Reviewer 4 Report

In the submitted manuscript by Renata Kovač and colleagues, entitled “Could an early treatment with GA and BA impact prolonged cold storage and shelf life of apricot?”, the authors study the early application of plant growth regulators (PGRs) on postharvest changes in apricot fruit. Overall, the manuscript is well-written, but the authors need additional data to support their study. The aim and scope of the Horticulturae journal are in line with the current manuscript.

1. To my opinion, the authors should use multivariance analytical tools such as correlation and/or PCA analysis to describe and present their data.

2. What about other quality traits such as weight or size of fruit and fruit dry matter?

Author Response

Responses to the Reviwer 4, horticulturae-2066492

To my opinion, the authors should use multivariance analytical tools such as correlation and/or PCA analysis to describe and present their data.
Thank you for suggestion. PCA factor-plane was inserted in manuscript (Figure 2) as well as text which describes, discuss factor-plane and explains how it was performed. Following text was added:

In material and method chapter:

“On data collected at same time and same frequency principal component analysis (PCA) was performed.”

In Results chapter:

Based on PCA analysis (Figure 2), the first two factors explained more than 70% of variability in the case of color, texture and all indicators of metabolic activities: TA, TSS, phenols, flavonoids, carotenoids, sugars and organic acids sampled at three sampling points (Figure 2A), while in case of sensory descriptors assessed after cold storage and shelf life it was more than 90% (Figure 2B). It is noticeable that most of the variation is explained by Factor 1 (55.66% and 75.98%, respectively). Observing the nature of sample separation in both cases, it could be tentatively assumed that Factor 1 represents the sampling time, thus leaving Factor 2 to be addressed to PGR treatments.

In Discussion chapter

Mentioned changes caused by PGR application, according to PCA analysis (Figure 2A and B) are tentatively assigned as Factor 2, which could explain only 15.34% and 14.82% of variability, respectively. Such small percentages coupled with relatively close proximity of samples after cold storage and shelf life pointed out a small impact, and thereby overall difference caused by the application of PGRs.

What about other quality traits such as weight or size of fruit and fruit dry matter?
The mentioned properties of the fruit are measured (width, length and height in mm), but only during the development (in several stages) of the fruit after treatment and until harvest. The application of PGR and their influence on the pomological properties of the fruit and fruit development were the subject of research, and will be published in another paper. The subject of this manuscript was focused on the difference in postharvest behaviour between treated and untreated apricots. However, the idea of measuring changes in the dimensions of individual fruits during storage and shelf life is interesting and has a potential since it is rarely treated in reports dealing with postharvest technology of fresh fruits.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors did sufficient revisions in the revised version and now it can be Accepted!

Author Response

The authors wish to thank the Editor and Reviewer for the useful and highly contributing inputs which improved our manuscript.

The authors

The authors wish to thank the Editor and Reviewers for the useful and highly contributing inputs which improved our manuscript.

The authors

Author Response File: Author Response.docx

Reviewer 3 Report

The authors corrected and completed the work very well. Please still improve the grammar of the language

Author Response

The authors wish to thank the Editor and Reviewer for the useful and highly contributing inputs which improved our manuscript.

We have made additional language corrections, as suggested. English language and grammar were checked and corrected by a native speaker. All the changes that were made can be tracked in the manuscript through the option: “Track changes”.

The authors

Author Response File: Author Response.docx

Reviewer 4 Report

All my concerns were successfully addressed.

Accept in present form

Author Response

The authors wish to thank the Editor and Reviewer for the useful and highly contributing inputs which improved our manuscript.

The authors

Author Response File: Author Response.docx