Iodine Biofortification of Potato (Solanum tuberosum L.) Grown in Field
, Stanisław Rożek 2,†, Włodzimierz Sady 1 and Piotr Strzetelski 2Round 1
Reviewer 1 Report
General comment:
The present work (agronomy-1011967) aimed to evaluate the effectiveness of potato fortification with iodine by soil and foliar fertilization. Overall, the manuscript is well organized and presents important data on relevant approaches to biofortify food with iodine. My main criticism goes to the organization of the field experiments. The authors wrote in lines 168-169 that “the accumulation of iodine in potato tubers was significantly affected by the applied method and chemical form of iodine”. Well, actually, as the experiment was carried out, it is hard to find out which variable (fertilization method or iodine chemical species) was responsible for the obtained results. In particular, the authors say that foliar application with KIO3 was more effective in fortifying potatoes. However, is this true because the foliar application is more effective than soil fertilization or because KIO3 is more effective than KI? To answer these questions, it would be necessary to apply KI or KIO3 both as foliar and as soil fertilization. Only then the authors would truly assess the influence of these two variables. That being said, I think this is the major flaw of this work. I would like to hear the authors’ opinion on this. Nevertheless, my opinion is that this manuscript can be published after careful proofreading (the quality of written English must be improved) and after addressing the specific comments given below.
Specific Comments:
(L.86) Further information on how these parameters were analyzed is required. Provide them. Authors only need to describe briefly how each parameter was analyzed.
(L.129) Is this fresh or dry sample? Is this a sample of just one potato or a composite sample? More information on the sample pre-treatment is needed. Provide it.
(L.130) How were these extraction conditions selected? The authors cite the EN 15111, but the conditions described here (e.g., ratio sample/extraction solution and temperature) are not the ones described in that EN. Explain.
(L.135-138) Add formulas instead of this text. It would be easier for the reader to understand how iodine uptake and RDA were calculated. Don't forget to write down the units of each term in the formula.
(L.146) city and country for the software
(L.165) I don't understand the letters in the figures. For example, for the control group, I imagine that there are no statistical differences between the DM of potatoes in the years 2009 and 2011. However, they have different letters (b for 2009 and a for 2011). How is this possible? Shouldn't it be letter a for 2008 and letter b for both 2009 and 2011? Are the authors comparing treatments or years? If they are comparing treatments, then the figure caption is not clear.
(L.170) “its dose”. Something is missing.
(L.173) "combination"?! Did you mean "treatment"? Replace
(L.199) Why 100 g? Is this the average amount consumed?
(L.203) Don't use the word “combination”! It seems that more than one treatment was applied at the same time and that's not the case. Replace by “treatment” or any other suitable word.
(L.263) iodides?? Replace by "iodide"! Do it throughout the manuscript. Do the same for "iodates"...
(L.322) “…is to our knowledge the first few-year study evaluating…” Remove this. Replace by “The current work evaluates the…”
(L.215) “Basing…”?! Correct
Author Response
Dear Reviewer,
First of all, I would like to thank for your time and effort put into evaluating the manuscript. Below I would like to response to all the concerns. All changes in the manuscript was marked by blue font.
In review: The present work (agronomy-1011967) aimed to evaluate the effectiveness of potato fortification with iodine by soil and foliar fertilization. Overall, the manuscript is well organized and presents important data on relevant approaches to biofortify food with iodine. My main criticism goes to the organization of the field experiments. The authors wrote in lines 168-169 that “the accumulation of iodine in potato tubers was significantly affected by the applied method and chemical form of iodine”. Well, actually, as the experiment was carried out, it is hard to find out which variable (fertilization method or iodine chemical species) was responsible for the obtained results. In particular, the authors say that foliar application with KIO3 was more effective in fortifying potatoes. However, is this true because the foliar application is more effective than soil fertilization or because KIO3 is more effective than KI? To answer these questions, it would be necessary to apply KI or KIO3 both as foliar and as soil fertilization. Only then the authors would truly assess the influence of these two variables. That being said, I think this is the major flaw of this work. I would like to hear the authors’ opinion on this. Nevertheless, my opinion is that this manuscript can be published after careful proofreading (the quality of written English must be improved) and after addressing the specific comments given below.
Dear Reviewer, your critical comment concerning the application of KIO3 only through foliar spraying and of KI – only through soil is truly valid. We do think it would be best to test the effect of these compounds through both soil and foliar application, optimally in a few doses. However, we had to limit the experimental design due to several factors.
The studies were conducted in 2008-2011 within the first project on iodine bioforitfiation on plants that was financially supported by the Ministry of Science and Higher Education (Project No. N N310 3081 34) „Biofortification of selected vegetable species with iodine depending on its dose and application method.” Along with potato, other vegetables (lettuce and carrot) were under the investigation using the same experimental design and the results have already been published [see also 2.1. Plant material, cultivation and treatments P 3 L 106]
- Smoleń, S.; Rożek, R.; Ledwożyw-Smoleń, I.; Strzetelski, P. Preliminary evaluation of the influence of soil fertilization and foliar nutrition with iodine on the efficiency of iodine biofortification and chemical composition of lettuce. J Elementol, 2011, 16(4), 613-622. DOI: 5601/jelem.2011.16.4.10
- Smoleń, S.; Rożek, S.; Strzetelski, P.; Ledwożyw-Smoleń, I. Preliminary evaluation of the influence of soil fertilization and foliar nutrition with iodine on the effectiveness of iodine biofortification and mineral composition of carrot. J Elementol, 2011, 16(1), 103-113.
The funding for the Project was granted after previous several applications and due to limited funding it was necessary to select one experimental design for all tested species, namely: potato, lettuce and carrot as presented in the current and previously mentioned works. The experimental design was developed in early spring 2008 basing on the current data literature and own preliminary studies with spinach and radish biofortification with iodine. We decided to foliarly apply only KIO3 as we had previously observed detrimental effect on foliar KI on spinach and radish plants. What is more, KI was chosen to be applied into soil as the literature analysis conducted at that time revealed its higher uptake by plants as compared to KIO3. We are aware that several years have passed since the completion of these studies but only now we have obtained additional funding to cover the expenses of the final publication of results concerning potato cultivation. Therefore, we would like to ask for understanding and acceptance of our explanation that would allow our work to be published.
We would also like to mention that the whole manuscript was carefully re-read and re-edited when necessary.
In review: Specific Comments:
(L.86) Further information on how these parameters were analyzed is required. Provide them. Authors only need to describe briefly how each parameter was analyzed.
Information provided as suggested (L: 86-98)
In review: (L.129) Is this fresh or dry sample? Is this a sample of just one potato or a composite sample? More information on the sample pre-treatment is needed. Provide it.
Information provided as suggested (L. 141-143)
In review: (L.130) How were these extraction conditions selected? The authors cite the EN 15111, but the conditions described here (e.g., ratio sample/extraction solution and temperature) are not the ones described in that EN. Explain.
Unfortunately, there was an editing mistake in a presented temperature for extraction as in fact it was 90°C, not 70°C. Ratio sample/extraction solution was chosen based on previous preliminary and already cited studies conducted by the Authors team, eg. 13. Smoleń, S.; Ledwożyw-Smoleń, I.; Sady, W. The role of exogenous humic and fulvic acids in iodine biofortification in spinach (Spinacia oleracea L.). Plant Soil, 2016, 402, 129–143. doi: 10.1007/s11104-015-2785-x. It needs to be underlined that for each plant or food material the sample/extraction solution ratio is chosen individually based on preliminary analysis of a material in order to ensure the proper data acquisition within the calibration range.
In review: (L.135-138) Add formulas instead of this text. It would be easier for the reader to understand how iodine uptake and RDA were calculated. Don't forget to write down the units of each term in the formula.
Corrected as suggested (L.147-151 )
In review: (L.146) city and country for the software
Information provided as suggested (L. 160)
(L.165) I don't understand the letters in the figures. For example, for the control group, I imagine that there are no statistical differences between the DM of potatoes in the years 2009 and 2011. However, they have different letters (b for 2009 and a for 2011). How is this possible? Shouldn't it be letter a for 2008 and letter b for both 2009 and 2011? Are the authors comparing treatments or years? If they are comparing treatments, then the figure caption is not clear.
The comparison was done between treatments within individual years as we thought was suggested by the respective colors. The captions of Figure 1 and further were corrected.
In review: (L.170) “its dose”. Something is missing.
Corrected as suggested
In review: (L.173) "combination"?! Did you mean "treatment"? Replace
Corrected as suggested.
In review: (L.199) Why 100 g? Is this the average amount consumed?
The portion of 100g was chosen in order to facilitate the comparison and discussion of obtained information on RDA-I coverage with the results presented by other research teams.
In review: (L.203) Don't use the word “combination”! It seems that more than one treatment was applied at the same time and that's not the case. Replace by “treatment” or any other suitable word.
Corrected as suggested in the whole body of manuscript
In review: (L.263) iodides?? Replace by "iodide"! Do it throughout the manuscript. Do the same for "iodates"...
Corrected as suggested in the whole body of manuscript
In review: (L.322) “…is to our knowledge the first few-year study evaluating…” Remove this. Replace by “The current work evaluates the…”
Corrected as suggested.
In review: (L.215) “Basing…”?! Correct
Corrected as suggested.
Reviewer 2 Report
The authors experimented with biofortification of potatoes using iodine. They found that foliar application was more effective than soil application and could provide a high amount of a person's recommended daily iodine intake. They also found that foliar application did not reduce yield or other quality traits.
This was a well designed experiment that addresses an important social problem. In general the figures and tables seemed repetitive and it would be good to come up with some ways to combine them. For instance are any of the measures in table 1 different enough year to year to be interesting? If so perhaps those values should be highlighted in the text and the table would be unnecessary. Similarly, figure 2 and 3 are almost identical. The findings of this study are important, but I think the length and detail of the paper make for a niche potential audience. I think a shorter more to the point paper would appeal to a broader audience.
There are also several unusual wording choices in this paper and I think it would be easier to read with some editing. Most notably prophylaxis, as I'm familiar with the term, connotes birth control. I googled it and it does just mean prevention, so it's being used correctly, but it reads weirdly and I'd just use "prevention". On line 21 "allowed to obtained" is a confusing phrase.
Author Response
Dear Reviewer,
First of all, I would like to thank for your time and effort put into evaluating the manuscript. Below I would like to response to all the concerns.
The authors experimented with biofortification of potatoes using iodine. They found that foliar application was more effective than soil application and could provide a high amount of a person's recommended daily iodine intake. They also found that foliar application did not reduce yield or other quality traits.
In review: This was a well designed experiment that addresses an important social problem. In general the figures and tables seemed repetitive and it would be good to come up with some ways to combine them. For instance are any of the measures in table 1 different enough year to year to be interesting? If so perhaps those values should be highlighted in the text and the table would be unnecessary. Similarly, figure 2 and 3 are almost identical. The findings of this study are important, but I think the length and detail of the paper make for a niche potential audience. I think a shorter more to the point paper would appeal to a broader audience.
The Table 1 presents the major characteristics of soil in each year of the study and taking into account that the experiment was conducted for three years in the field conditions we found it important to present them as clearly as possible. The Figures 2 and 3 present two separate parameters, namely iodine content in tubers and iodine uptake by potato yield in individual years of the study. We decided to show the full results of statistical analysis of obtained results using two-way ANOVA. The results presented in tables are the mean values for three years of the study and show the statistical difference for the treatment x year interaction. Figures were included to present detailed data for individual years in order to show differences that were related to various conditions that occurred in various years of the study. We decided to use that way of data presentation based on own previous experience regarding the publication of results of multiple-year field studies.
In review: There are also several unusual wording choices in this paper and I think it would be easier to read with some editing. Most notably prophylaxis, as I'm familiar with the term, connotes birth control. I googled it and it does just mean prevention, so it's being used correctly, but it reads weirdly and I'd just use "prevention". On line 21 "allowed to obtained" is a confusing phrase.
The whole manuscript was carefully re-read and re-edited when necessary. Both terms “prophylaxis” and “prevention” is commonly used in the literature on the micronutrient deficiency and used approaches of its counteraction, but we decided to follow your suggestion.
