In Situ Sucrose Injection for Alteration of Carbohydrate Reserve Dynamics in Grapevine

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors Specific comments are as follows: 1. The main question addressed by the research is how to improve the fruitfulness and yield of sub-tropical table grape vines, particularly in relation to carbohydrate reserves during flowering. Specifically, the study investigates the efficacy of continuous trunk injection of sucrose solution in enhancing carbohydrate reserves and subsequently improving vine fruitfulness. 2. The topic is both original and relevant in the field because it addresses a specific gap related to managing carbohydrate reserves in grapevines, which can affect yield consistency. While there is existing knowledge about the importance of carbohydrate reserves in vine development, this research contributes by exploring a novel method of supplementing these reserves through trunk injection of sucrose solution. 3. Compared with other published material, this research adds a novel approach to addressing the issue of inconsistent yielding in sub-tropical table grape vines. While other studies may have examined the role of carbohydrate reserves, few have likely explored the direct injection of sucrose solution into the trunk as a means of supplementing these reserves. 4. Regarding methodology, the authors should consider implementing further controls to address variability in injection rates, such as assessing and standardizing the health of the xylem before injection. Additionally, controlling for factors such as vine age, health, and environmental conditions could help isolate the effects of sucrose injection on fruitfulness and yield. 5. The conclusions drawn from the evidence presented are generally consistent. The study acknowledges the decline in solution uptake due to necrosis around injection sites and suggests further evaluation of sucrose injection in field vines without pathogen complications. The conclusions also highlight the importance of considering bud TNC rather than trunk and root TNC concentrations in relation to fruitfulness, which aligns with the evidence presented regarding the lack of significant response to sucrose injection. 6. The references provided appear appropriate for supporting the background information and context of the study. However, it would be beneficial for the authors to include more recent references if available, particularly regarding similar studies or advancements in vine management practices. 7. Regarding tables and figures, it would be helpful for the authors to include more detailed data on sucrose injection rates, vine health assessments, and yield outcomes to better support their conclusions and facilitate comparison with other studies in the field. Additionally, providing graphical representations of key findings could enhance the clarity and visual appeal of the results. Comments on the Quality of English Language

In general Quality of English needs to be refined in some fragments.

Author Response

Reviewer 1: Specific comments are as follows:

1. The main question addressed by the research is how to improve the fruitfulness and yield of sub-tropical table grape vines, particularly in relation to carbohydrate reserves during flowering. Specifically, the study investigates the efficacy of continuous trunk injection of sucrose solution in enhancing carbohydrate reserves and subsequently improving vine fruitfulness.

>> The reviewer correctly summarises the intent of the paper. Thank you.

2. The topic is both original and relevant in the field because it addresses a specific gap related to managing carbohydrate reserves in grapevines, which can affect yield consistency. While there is existing knowledge about the importance of carbohydrate reserves in vine development, this research contributes by exploring a novel method of supplementing these reserves through trunk injection of sucrose solution.

>>Thank you.

3. Compared with other published material, this research adds a novel approach to addressing the issue of inconsistent yielding in sub-tropical table grape vines. While other studies may have examined the role of carbohydrate reserves, few have likely explored the direct injection of sucrose solution into the trunk as a means of supplementing these reserves.

>>None that we are aware of.

4. Regarding methodology, the authors should consider implementing further controls to address variability in injection rates, such as assessing and standardizing the health of the xylem before injection. Additionally, controlling for factors such as vine age, health, and environmental conditions could help isolate the effects of sucrose injection on fruitfulness and yield.

>>Indeed yes, and thanks for the suggestions which we will take on board for the future. We did work on a commercial vineyard of vines of the same cultivar, age and management history in an attempt to use uniform material. It was our investigations for causes of the variability in sucrose loading that led to the diagnosis of vascular disease (which led to subsequent actions by the grower to control this issue). We have commented on this issue, [ ‘Areas of xylem around the injection drill holes had also become necrotic by the following season. ‘And, ‘However, a consistent decline in solution uptake was observed, related to a necrosis of tissue around the drill wound of the injection site. Further, extensive areas of necrotic xylem existed within the vines, most likely contributing to variability in injection rates between injection sites. Assessment of xylem health is therefore necessary before trunk injection.’] to the effect that future researchers should evaluate vascular health.

5. The conclusions drawn from the evidence presented are generally consistent. The study acknowledges the decline in solution uptake due to necrosis around injection sites and suggests further evaluation of sucrose injection in field vines without pathogen complications. The conclusions also highlight the importance of considering bud TNC rather than trunk and root TNC concentrations in relation to fruitfulness, which aligns with the evidence presented regarding the lack of significant response to sucrose injection.

>>Thank you.

6. The references provided appear appropriate for supporting the background information and context of the study. However, it would be beneficial for the authors to include more recent references if available, particularly regarding similar studies or advancements in vine management practices.

>>We have searched for more recent references, and we have updated references [1,4,24} although these are also from 2021.

7. Regarding tables and figures, it would be helpful for the authors to include more detailed data on sucrose injection rates, vine health assessments, and yield outcomes to better support their conclusions and facilitate comparison with other studies in the field.

>>We believe we have provided all the relevant data we have on vine health and yield, and on sucrose injection rates. Some are included in the Supplementary materials 1

Additionally, providing graphical representations of key findings could enhance the clarity and visual appeal of the results.

>>>Given the short time for revision, and with authors now on three continents, we have not been able to do this.

Reviewer 2 Report

Comments and Suggestions for Authors

The abstract should contain information about the whole experiment not only about the results. Please include a few details about the materials and methods too.

References and table citations are not complete, please check and include all of them: “Error! Reference source not found...”

Lines are not numbered, therefore giving suggestions to the text errors is difficult. Please check the spelling as there are many errors in the text: “This study monitored the seasonal carbohydrate dynamics in trunk and roots of > taqble < grape vines grown in the”; “and higher > presuures < resulting in fluid leakage”; “gas compressor was was used to deliver compressed”; 

The results are valuable, although it is a question if the observed results of the treatment are the consequence of the treatment itself or the necrotic infection. This should be interpreted in more detailed as in the present form it questions all results of the treatments. Did the authors find necrotic infection on untreated vines or only on the treated ones? Why the investigation of the woody parts was necessary? Had the authors any former experience with the infection caused by the treatments?

Comments on the Quality of English Language

The english needs a moderate correction as the text has several errors. 

Author Response

Reviewer 2

The abstract should contain information about the whole experiment not only about the results. Please include a few details about the materials and methods too.

>>The abstract has been slightly modified to include some details on the experiment but not to drastically exceed the recommend number of words in the Abstract.

References and table citations are not complete, please check and include all of them: “Error! Reference source not found...”

>>>This problem occurred when the manuscript was converted from our Word file, which was complete with correct references to citations, Tables, and Figures, to the MDPI Agronomy format. I trust that the final version will not show this problem.

Lines are not numbered, therefore giving suggestions to the text errors is difficult.

>>>Again, in the submitted version lines were numbered, so the numbering has been lost occurred when the manuscript was converted from our Word file.

Please check the spelling as there are many errors in the text: “This study monitored the seasonal carbohydrate dynamics in trunk and roots of > taqble < grape vines grown in the”; “and higher > presuures < resulting in fluid leakage”; “gas compressor was was used to deliver compressed”; 

>>Thank you and apologies that these slipped through our editing; we have now revised the whole text to correct these and other spelling mistakes.

The results are valuable, although it is a question if the observed results of the treatment are the consequence of the treatment itself or the necrotic infection. This should be interpreted in more detail as in the present form it questions all results of the treatments.

>>Thank you, we have now included a short section [line 360-361 and 369-370] indicating that necrosis was probably an issue in 2015, but less so in 2014. We had already mentioned ‘Areas of xylem around the injection drill holes had also become necrotic by the following season. ‘And, ‘However, a consistent decline in solution uptake was observed, related to a necrosis of tissue around the drill wound of the injection site. Further, extensive areas of necrotic xylem existed within the vines, most likely contributing to variability in injection rates between injection sites. Assessment of xylem health is therefore necessary before trunk injection.’

>>Did the authors find necrotic infection on untreated vines or only on the treated ones?

>>The vines selected for necrosis included three injected and two controls, both behaving similarly. See line 353 and 355

Why the investigation of the woody parts was necessary?

>> Since the trunk and roots serve as CHO storage sites and depletion of stored CHO starts from the cane to the trunk, the only potential part to allow for pressurized injection into the intercellular spaces of xylem is trunk. Since we observed great variability between vines in injection rate into the trunk, we attempted to understand some of the basis for this variability.

Had the authors any former experience with the infection caused by the treatments?

>>No, this was our first field experiment with the injection method. However, we did undertake several injection exercises in one- to two-year old vines with different concentrations of sucrose and different levels of pressures before starting this experimentation in the field. Some of those studies are summarized by ourselves in: Fruits 76 (3) 107-115 | DOI: 10.17660/th2021/76.3.1

Reviewer 3 Report

Comments and Suggestions for Authors

The work attempts to analyze the seasonal dynamics of carbohydrates in table grape vines and is interesting with the use of carbohydrate stem injection during the stage of greatest demand to determine the effect on the vine fruitfulness and yield. The above is important since it helps to better understand the importance of promoting greater carbohydrate production in grape vines. In general, the work is good, but it is necessary to correct some small errors in the grammar of the document; in addition to adding a couple of references or ideas to improve the work. In general, the conclusions are consistent with the results and objectives of the work. Therefore, the work has the quality so that once the authors review the comments in the attached document (PDF), the manuscript can continue with the publication process.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

The quality of the English language is good, just a few typos

Author Response

Reviewer 3

 

The work attempts to analyze the seasonal dynamics of carbohydrates in table grape vines and is interesting with the use of carbohydrate stem injection during the stage of greatest demand to determine the effect on the vine fruitfulness and yield. The above is important since it helps to better understand the importance of promoting greater carbohydrate production in grape vines. In general, the work is good, but it is necessary to correct some small errors in the grammar of the document; in addition to adding a couple of references or ideas to improve the work.

 

>>Thank you, we have corrected the issues related to grammar and spelling. We had indicated that further work is required before this will become a practical reality ‘Assessment of xylem health is therefore necessary before trunk injection ‘and ‘There are various methods of detecting decay within trees or vines. For example, the Tree Radar Unit™ (TRU™) is a non-invasive method. Such technology could be used to quantify decay in the trunk and root, and then utilised with a management plan for vine replacement or treatment of the causal agent if sucrose injection were to become a useful management practice.’

 

We had also work earlier on the improvement in sucrose injection. Our work published showed that K⁺ ions improved hydraulic conductance of grapevine shoots for sucrose loading, aimed at manipulation of vine carbohydrate reserves [Fruits 76 (3) 107-115 | DOI: 10.17660/th2021/76.3.1 ]

 

In general, the conclusions are consistent with the results and objectives of the work. Therefore, the work has the quality so that once the authors review the comments in the attached document (PDF), the manuscript can continue with the publication process.

>>We have reviewed the reviewer’s comments and taken them all on board in the updated version.

Reviewer 4 Report

Comments and Suggestions for Authors

Dear Authors,

Grapes are a significant crop for humanity and will always represent a focus point of research. The issues present in this paper are actual and, unfortunately, will remain actual many years from now on, due to climate change.

The research released in the article could be useful for table grape growers in deciding the proper maintenance technologies in challenging areas.

The article has an interesting view of data and is well-documented for a better understanding of the presented research.

The paper is well described and the methods used are scientifically appropriate. Only a few points should be addressed by the authors:

-          In Table 5, authors should check the following data: The number of inflorescences counted per vine for Control is 7.7 and for the same variant, the number of bunches per vine at harvest is 7.8 – it should not have been lower than control.

-     ”Error! Reference source not found..” –please verify this kind of situation all over the paper.    

- the references section could include more recent studies, only one study from 2021.

 

Thank you!

Comments for author File: Comments.pdf

Author Response

Reviewer 4

Grapes are a significant crop for humanity and will always represent a focus point of research. The issues present in this paper are actual and, unfortunately, will remain actual many years from now on, due to climate change. The research released in the article could be useful for table grape growers in deciding the proper maintenance technologies in challenging areas.

>>Thank you for your positive comment.

The article has an interesting view of data and is well-documented for a better understanding of the presented research. The paper is well described and the methods used are scientifically appropriate. Only a few points should be addressed by the authors:

In Table 5, authors should check the following data: The number of inflorescences counted per vine for Control is 7.7 and for the same variant, the number of bunches per vine at harvest is 7.8 – it should not have been lower than control.

>> Thank you for pointing out the discrepency. This is true, but with the sampling errors and rounding up/down, these are the exact results. Indeed upon reflection it was 7.77. So, we have changed the inflorescence per vine to be consistent at 7.8.

”Error! Reference source not found..” –please verify this kind of situation all over the paper. 

>>This problem occurred when the manuscript was converted from our Word file, which was complete with correct references to citations, Tables, and Figures, to the MDPI Agronomy format. I trust that the final version will not show this problem.

The references section could include more recent studies, only one study from 2021.

>>We have included three updated studies [1, 4, 24 ] although also from 2021. The lack of recent studies specially in trunk injection illustrates that this is a very new possible practical approach to addressing the inconsistent yielding of sub-tropical table grape.