Advancing Sustainability in Pelargonium Nursery Management: Scientific Exploration of an Innovative Prolonged Cold Storage System for Cuttings

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Italize Pelargonium zonale, P. peltatum and P. zonale × peltatum in the entire manuscript. 

Why diferent number: Fifteen and 21 varieties? Explain in detail. 

Results: in the second year all varieties had problems rooting after cold storage - this must be elaborated. I seems to me that the most important factor is the production in the exporter country. This can be improved by legal measures and contracts, downing the initial costs. 

Also, chlorophyll was generally lower in the second year. This needs further elaboration.

Cuttings from 2022 were less hydrated than those from 2021 This can be explained by possible differences in production and stock plant nursery management, especially fertilization and watering - this is a crucial point going back to the point above. Mutual contracts must step into the process, otherwise you never know how high or low quality you are going to get. 

A negative correlation was observed between the nitrogen (N) content and rooting efficiency - apical domination of aboveground parts is crucial here. Rooting shall always be impaired if high nitrogen amounts are available to growing points and meristems. 

An increased number of days prolonged to 2 weeks is not enough to state the following strong acclamation: 'Developing such an eco-friendly method for storing unrooted pelargonium cuttings would make it possible to manipulate the seasonality of the cuttings market and significantly enhance the sustainability of the production of this species.'

Without extensive LCA this can not be stated: minimizes the environmental impact.

Author Response

Answer to Review 1

Dear Reviewer,

I sincerely appreciate the time and effort you have devoted to reviewing our manuscript. Your insightful comments and constructive suggestions have been invaluable in improving the quality and clarity of our work.

We have carefully addressed all the points you raised, making the necessary revisions to enhance the manuscript accordingly. We believe these changes have significantly strengthened the overall quality of the study.

Detailed answers below

1. Italize Pelargonium zonale, P. peltatum and P. zonale × peltatum in the entire manuscript. 

Corrected

2. Why different numbers: Fifteen and 21 varieties? Explain in detail. 

The discrepancy in the number of varieties can be attributed to the execution of the experiment under the operational conditions of the company. The selection of varieties was contingent upon market demand and trends. Consequently, certain varieties that were examined in 2021 were not incorporated into the 2022 study. Conversely, the decision was taken to augment the number of varieties in 2022.

We added this explanation to the M&M 2.1.

3. Results: in the second year all varieties had problems rooting after cold storage - this must be elaborated. I seems to me that the most important factor is the production in the exporter country. This can be improved by legal measures and contracts, downing the initial costs. 

The reviewer's assertion is indeed correct. It is also noteworthy that not all potential eventualities can be encompassed within the contractual framework, such as extreme weather events. In general, during the summer/autumn months of 2022, stock plants experienced elevated temperatures and drought, which can be classified as a physiological stressor. Consequently, due to the suboptimal growth rate of the maternal plants prior to harvesting, it was determined that enhancing the growth rate would be achieved through an increase in nitrogen fertilisation. This strategy was supported by the findings of our mineral compound analysis.

We added this explanation to the discussion.

4. Also, chlorophyll was generally lower in the second year. This needs further elaboration.

We discuss this finding in our previous paper (Rapacz et al. 2024). In our case, the SPAD measure was found to be uncorrelated with the nitrogen content of plants, while certain chlorophyll fluorescence transient parameters exhibited a correlation. This outcome is likely attributable to the pre-stressing of mother plants, a process that has been demonstrated to induce alterations in leaf anatomy. It is important to note that the SPAD index is sensitive to leaf thickness. See: e.g. Neufeld, H. S., Chappelka, A. H., Somers, G. L., Odom, J. W., & Skelly, J. M. (2002). Use of the SPAD-502 meter to determine chlorophyll concentration in leaves of woody plants. HortTechnology, 12(4), 682–686. https://doi.org/10.21273/HORTTECH.12.4.682.

We added this explanation to the discussion.

5. Cuttings from 2022 were less hydrated than those from 2021 This can be explained by possible differences in production and stock plant nursery management, especially fertilization and watering - this is a crucial point going back to the point above. Mutual contracts must step into the process, otherwise you never know how high or low quality you are going to get. 

Yes, Thank you for your valuable feedback. It was explained in point 3 and partially 4.

6. A negative correlation was observed between the nitrogen (N) content and rooting efficiency - apical domination of aboveground parts is crucial here. Rooting shall always be impaired if high nitrogen amounts are available to growing points and meristems. 

Yes, the reviewer is right. We appreciate the reviewer’s insightful comment. It was explained in points 3 and partially 4.

This information was added to the discussion

We added publication for reference Mi, G., Chen, F., & Zhang, F. (2008). Multiple signaling pathways control nitrogen-mediated root elongation in maize. Plant Signaling & Behavior, 3(11), 1030–1032.doi: 10.4161/psb.6800

7. An increased number of days prolonged to 2 weeks is not enough to state the following strong acclamation: 'Developing such an eco-friendly method for storing unrooted pelargonium cuttings would make it possible to manipulate the seasonality of the cuttings market and significantly enhance the sustainability of the production of this species.'

Thank the reviewer for this comment. We have softened the tone of the statement indicated.

"Extending the storage period of unrooted pelargonium cuttings by up to two weeks using a more eco-friendly method may offer limited potential to influence market seasonality and could contribute modestly to improving the sustainability of pelargonium production. However, further studies are needed to confirm these possibilities."

8. Without extensive LCA this can not be stated: minimizes the environmental impact.

We appreciate the reviewer’s point regarding the need for extensive LCA. However, our statement is based on a comparative assessment limited to the specific technological changes introduced, using consistent boundaries and metrics. Although we do not conduct a full cradle-to-grave Life Cycle Assessment (LCA), we have transparently evaluated the environmental impact of the modified process stages. Therefore, the conclusion regarding reduced environmental impact is justified within the defined scope.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors, 

I read the research manuscript devoted to cold storage of Pelargonium zonale, P. peltatum, and hybrids cuttings  and the conditions that are optimal for their rooting. The results are valuable from practical point of view related to economic viability; greenhouse production.

Please, refrain from using the phrase "for the first time". The village women use the cold storage method to preserve the cuttings of Pelargonium through the winter for decades and they obtain empirical knowledge. I agree that here you present precise parameters for the conditions of the storage, seaking for maximum success.  Please italise all scientific plant names - none in the abstract is italised and some in he introduction part. Also you use as a common name pelargonium  and Geranium. pick just one and stick to it in the whole paper.

Author Response

Answer to Review 2

Dear Reviewer,

Thank you for your thoughtful feedback and for contributing to the refinement of our research. We have carefully addressed all the points you raised, making the necessary revisions to enhance the manuscript accordingly. We believe these changes have significantly strengthened the overall quality of the study.

• Please, refrain from using the phrase "for the first time". The village women use the cold storage method to preserve the cuttings of Pelargonium through the winter for decades and they obtain empirical knowledge. I agree that here you present precise parameters for the conditions of the storage, seaking for maximum success.  Please italise all scientific plant names - none in the abstract is italised and some in he introduction part. Also you use as a common name pelargonium  and Geranium. pick just one and stick to it in the whole paper.

We are grateful for those remarks. All the suggestions have been addressed: we deleted “for the first time” in the abstract and conclusions, corrected Italics, and changed Geraniums into Pelargoniums, which is the proper name than the common name Geranium.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors,

Congratulations on your work, which contributes valuable information regarding the management of genetic materials for Pelargonium production.

However, I would like to request clarification on several points:

**Section 2.2**  
- Please clarify the composition of the growing medium used in your study.  
- Was light intensity continuously monitored throughout the study? If so, do you have data that could be included in a table? It would be helpful to see the trend of light intensity in relation to root formation. Additionally, can you clarify what you mean by "The light intensity setpoint for sharing was 30 Klx"?  
- Has the electrical conductivity of the nutrient solution been measured?  

**Section 2.6**  
- During the surveys conducted, were the values for light, temperature, and humidity recorded?  
- For Figures 2 and 3, please include letters indicating significant differences.  
- In Table 5, it would be preferable to reduce the values to one decimal place.  

Lastly, please ensure that the references are updated with more recent papers. 

Thank you.

Author Response

Answer to Review 3

Dear Reviewer,
Thank you for your thoughtful feedback and for contributing to the refinement of our research. We have carefully addressed all the points you raised, making the necessary revisions to enhance the manuscript accordingly. We believe these changes have significantly strengthened the overall quality of the study.

Detailed answers below:

**Section 2.2**  

- Please clarify the composition of the growing medium used in your study.  –

This substrate was a composition labelled with the supplier's code (SoMi 537), consisting of: 30% coconut fibre, 40% fine sod peat, 15% polystyrene, 15% perlite, wetting agent, pH 5.3.

This more precise information was added to the text.

Was light intensity continuously monitored throughout the study? If so, do you have data that could be included in a table? It would be helpful to see the trend of light intensity in relation to root formation.

The light intensity was measured but not recorded, and we do not have the possibility to obtain this data.

Additionally, can you clarify what you mean by "The light intensity setpoint for sharing was 30 Klx"?  

The light intensity setpoint for shading was 30 Klx  

This sentence means that the shading system (automatic shading in a greenhouse provided by movable screens) was activated when the light intensity reached 30 kilolux (klx) about 500 µmol/m²/s PPFD (Photosynthetic Photon Flux Density)

The text was updated with this explanation

- Has the electrical conductivity of the nutrient solution been measured?  

Yes, the computer system measured and monitored the electrical conductivity (EC) of the nutrient solution in fertigation, which ranged from 1.0 to 1.5 mS/cm during the experiment. This information was added to the text.

**Section 2.6**  - During the surveys conducted, were the values for light, temperature, and humidity recorded?  

Yes, the values are updated in the text. During the SPAD measurements, the environmental parameters were: light intensity, 10-16 klx (200-300 µmol/m²/s); temperature. 20-21°C; relative humidity 60-70%

- For Figures 2 and 3, please include letters indicating significant differences.  

Unfortunately, it is not possible to indicate the letters for the homogeneity groups in Figures 2 and 3. The letters would be too small, and the entire figure would be illegible (many bars would have to be marked with multiple letters). However, please note that statistically significant differences are currently marked. If the error bars do not overlap, the difference is statistically significant at P = 0.05. 'The means ± confidence intervals for P=0.05'.

- In Table 5, it would be preferable to reduce the values to one decimal place.  

- Corrected

Lastly, please ensure that the references are updated with more recent papers. 

Thank you very much for your thoughtful feedback. We would like to clarify that our manuscript, in its current form, incorporates 17 references from 2020 or later. We have selected these sources to ensure that our study is grounded in the most up-to-date research.

We added the following newer publications connected with pelargonium cultivation:

Altobaishi, S. F., Almana, F. A., Abd-ElGawad, A. M., Al-Yafrsi, M. A., & Elhindi, K. M. (2023). Ivy Geranium (Pelargonium peltatum (L.) L’Hér.) Plant growth and flowering as affected by mineral or biofertilizer with or without compost amendment. Agriculture, 13(5), 1106.

Darras, A. I., Grigoropoulou, K., Dimiza, K., & Zulfiqar, F. (2022). Effects of Brief UV-C Irradiation Treatments on Rooting Performance of Pelargonium× hortorum (LH Bailey) Stem Cuttings. Horticulturae, 8(10), 897.

Loconsole, D., Cristiano, G., & De Lucia, B. (2023). Biostimulant application, under reduced nutrient supply, enhances quality and sustainability of ornamental containerized transplants. Agronomy, 13(3), 765.

We updated two publications for reference in  Discussion:

Neufeld, H. S., Chappelka, A. H., Somers, G. L., Odom, J. W., & Skelly, J. M. (2002). Use of the SPAD-502 meter to determine chlorophyll concentration in leaves of woody plants. HortTechnology, 12(4), 682–686. https://doi.org/10.21273/HORTTECH.12.4.682.

Mi, G., Chen, F., & Zhang, F. (2008). Multiple signaling pathways control nitrogen-mediated root elongation in maize. Plant Signaling & Behavior, 3(11), 1030–1032.doi: 10.4161/psb.6800

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors This study demonstrates significant applied value with compelling results. However, several issues require attention prior to publication: -The authors mention screening "representative varieties" (5 in 2021, 6 in 2022) for moisture/metal content tests, but this description lacks clarity. A more detailed rationale for selection criteria is needed. Notably, the 2022 cohort includes 1 P. peltatum × zonale, 3 P. zonale, and 2 P. peltatum. The unbalanced species representation (e.g., why not 2 per species?) warrants explicit justification to avoid selection bias concerns. -Figures 1-2 reveal dramatic performance differences between varieties across years. While the authors acknowledge significant genotype effects, the pronounced annual variability within the same variety (e.g., Flower Fairy Red Splash, Champion Red Improved) requires deeper discussion. -Figures 2-3: Implement visual cues (e.g., color-coded variety names, species-specific symbols/patterns) to distinguish between P. peltatum, P. zonale, and hybrids. -Figure 4: Align species ordering with Figures 2-3 for cross-figure consistency. -Figure 6B Formatting Issues：Correct the overlapped y-axis label ("7000") and missing panel label "D". -Conclusion: Streamline the conclusion to eliminate redundancies. Remove the extraneous period at the final sentence's end. -Ensure all Latin species names and statistical terms (e.g., P-values) are italicized throughout the manuscript. Perform a full-text check for consistency. -Standardize paragraph indentation across all sections (e.g., Sections 2.2, 2.6) to maintain formatting coherence.

Author Response

Response to Reviewer 4:

Dear Reviewer,

I sincerely appreciate the time and effort you have devoted to reviewing our manuscript. Your insightful comments and constructive suggestions have been invaluable in improving the quality and clarity of our work.

We have carefully addressed all the points you raised, making the necessary revisions to enhance the manuscript accordingly. We believe these changes have significantly strengthened the overall quality of the study.

Detailed answers below

-The authors mention screening "representative varieties" (5 in 2021, 6 in 2022) for moisture/metal content tests, but this description lacks clarity. A more detailed rationale for selection criteria is needed. Notably, the 2022 cohort includes 1 P. peltatum × zonale, 3 P. zonale, and 2 P. peltatum. The unbalanced species representation (e.g., why not 2 per species?) warrants explicit justification to avoid selection bias concerns.

The discrepancy in the number of varieties can be attributed to the execution of the experiment under the operational conditions of the company. The selection of varieties was contingent upon market demand and trends. Consequently, certain varieties examined in 2021 were not included in the 2022 study. Conversely, the decision was taken to augment the number of varieties in 2022.

As scientists collaborating with the producer in this experiment, we did not influence the selection of varieties; we only used those selected by the Plantpol production department. In practical terms, producers cannot afford to grow varieties with low sales potential due to financial constraints. In nurseries engaged in mass production, the selection of varieties is modified each year.

Our study focused on identifying trends that characterize species or groups of varieties rather than examining individual varieties. This approach allows for the adjustment of cuttings' storage duration to the zonale, peltatum, or hybrid groups.

We added this explanation to the M&M 2.1.

 -Figures 1-2 reveal dramatic performance differences between varieties across years. While the authors acknowledge significant genotype effects, the pronounced annual variability within the same variety (e.g., Flower Fairy Red Splash, Champion Red Improved) requires deeper discussion.

In the summer and autumn of 2022, plant stocks experienced higher-than-usual temperatures and, consequently, physiological drought. Because the mother plants did not grow as well before being picked, we decided that adding more nitrogen would help them grow better. We thought that how plants reacted to the stress and with higher N fertilisation rate was variety-dependent. Although it is different to compare the same variety in both years as the results are different.

• 2, 3, 4 and 6D:

We are grateful for those remarks. All the figures were corrected according to the comments.

• Conclusion: Streamline the conclusion to eliminate redundancies. Remove the extraneous period at the final sentence's end.

Corrected

• Ensure all Latin species names and statistical terms (e.g., P-values) are italicized throughout the manuscript. Perform a full-text check for consistency.

Corrected

• Standardize paragraph indentation across all sections (e.g., Sections 2.2, 2.6) to maintain formatting coherence.

Corrected, I hope that it will be visible in the Reviewer version.

Author Response File: Author Response.pdf