Mechanism of Iron Transport in the Triticum aestivum L.–Soil System: Perception from a Pot Experiment
, Jihong Liu 1,2, Jianhua Wang 3, Xiaolong Duan 1,2 and Lingzhi Yang 4
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear authors, the manuscript "Mechanism of Iron Transport in Wheat-Soil System: Perception from a Pot Experiment" is quite interesting and worth investigation. Please see some comments:
1- Please double-check formatting and grammar, for instance ...body [9-10]... instead of ...body[9-10]....
2- The manuscript was well-designed, and it is well-discussed. The ICP-MS analysis has provided a solid clear trend on it. In this sense, why did you explored other metals? There are sinergistic effects.
3- Conclusion should be only one paragraph, please the abstract and conclusion should be composed of the most improtant numerical data, in order to see a clear trend on it.
Regards
Author Response
Dear authors, the manuscript "Mechanism of Iron Transport in Wheat-Soil System: Perception from a Pot Experiment" is quite interesting and worth investigation. Please see some comments:
1.Please double-check formatting and grammar, for instance ...body [9-10]... instead of ...body[9-10]....
Response: As suggested, we have checked the formatting and grammar in the whole manuscript and highlighted the amendments in red in the revised manuscript.
2.The manuscript was well-designed, and it is well-discussed. The ICP-MS analysis has provided a solid clear trend on it. In this sense, why did you explored other metals? There are synergistic effects.
Response: Thank you for your good suggestion. We didn’t consider the synergistic effects of elements. It is a pity that we did not explore other metals in sample analysis. We are willing to integrate this idea into our new research.
3.Conclusion should be only one paragraph, please the abstract and conclusion should be composed of the most important numerical data, in order to see a clear trend on it.
Response:Thank you for your comments. As suggested, We have merged and optimized the conclusion section and made some cuts and polishes to make the conclusion clearer. The revised portions are highlighted in red.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors present an important study regarding iron supplementation in soils to enhance iron concentration in wheat seeds.
Overall, the manuscript is well written and easy to follow. However, several sections lack information that guarantee the reproducibility of the study as well as its possible application in wheat fields elsewhere.
The authors will find a commented PDF file attached, which I hope will help improve the manuscript prior to publication.
Comments for author File: 
Comments.pdf
Author Response
The authors present an important study regarding iron supplementation in soils to enhance iron concentration in wheat seeds.
Overall, the manuscript is well written and easy to follow. However, several sections lack information that guarantee the reproducibility of the study as well as its possible application in wheat fields elsewhere.
The authors will find a commented PDF file attached, which I hope will help improve the manuscript prior to publication.
Thank you very much for your careful correction of our manuscript. At the same time, thank you for your valuable comments on our article, which are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. As suggested, we have made modifications one by one and highlight the amendments in red in the revised manuscript. Below, we have answered each question.
1.Please be careful with such claims. Increasing wheat yield alone is not the only strategy to solve food shortage. This issue is far more complex than this, and warrants a nuanced approach.
Response: Thank you for your comments. As suggested, in order to make the expression more reasonable, we have replaced this sentence in the manuscript with “and increasing its yield is one of the effectively ways to solve the problem of food shortage caused by rapid population growth” , and highlighted in red.
2.Maybe change to "is usually neglected"? Or "is neglected in large production systems"? These broad generalizations are not helpful in describing such nuanced problems.
Response: As suggested, in the revised manuscript, we have replaced “ has been neglected ” with “ is neglected in large production systems” , and highlighted in red.
3.This is not necessarily as causal as the authors affirm. It is enough to say that Iron is usually absent in traditional fertilizers, and this may lead to an iron imbalance in the soil-plant system, for example.
Response: As suggested, in the revised manuscript, we have replaced “ Thus, it leads to the increasingly serious iron imbalance in the soil-plant system” with “ The utilization of these conventional fertilizers, which usually lack iron, can lead to an iron deficiency in the soil-plant system. ” , and highlighted in red.
4.Please describe the "hidden hunger" phenomenon better.
Response: Thank you for your comments. As suggested, in the revised manuscript, We have further described the phenomenon of "hidden hunger" as follows: Such a deficiency not only decreases agricultural yields but also impacts human health through “hidden hunger”, an insidious form of micronutrient (Fe) deficiency that can hinder growth, weaken immune function, and lead to anemia.
5.Unnecessary adjective.
Response: Thank you for your comments. As suggested, in the revised manuscript, we have deleted the adjective “hot”.
6.Ca++
Response: Thank you for your comments. We have already corrected this error in the revised manuscript.
7.we
Response: Thank you for your comments. We have corrected this expression in the revised manuscript.
8.Which species and cultivar of wheat? From where? How were they obtained and prepared for sowing?
Response: Thank you for your comments. We have added to the revised manuscript the varieties of wheat, where it is produced and the preparations made before planting, and highlighted in red.
9.It would be very important to describe the physicochemical properties of the studied soil to allow for reproducibility. If this study is to be read by someone in another country or region, knowing the characteristics of the soil is extremely important for the reader to know if the results of this study are applicable to their conditions.
Response: Thank you for your comments. As suggested, we have added relevant content on soil physicochemical properties in the revised manuscript and highlighted it in red.
10.The unit "cm" is separate from the value, i.e. "35 cm". Please check throughout the manuscript that units are separate from values.
Response: Thank you for your comments. We have checked the whole manuscript and corrected the error that you have pointed out.
11.Please describe early on the source of iron used.
Response: As suggested, We have already indicated the iron source used as early as possible in the revised manuscript and highlighted it in red.
12. Please indicate the concentrations instead of saying "varying concentration levels", because this phrase is unnecessary otherwise.
Response: Thank you for your comments. As suggested, We have replaced "different concentration levels" with specific concentration values in the revised manuscript and highlighted it in red.
13.It would be good to indicate that the left panel refers to the jointing stage and the right panel refers to the reproductive stage, for faster interpretation of the results.
Response: Thank you for your comments. As suggested, We have made adjustments to the caption of Figure 3 and highlighted it in red.
14.From whom? If possible, please cite the appropriate sources of data.
Response: As suggested, We have added relevant literature to explain the complexation mechanism between iron and citric acid. The added literature has been highlighted in red at the reference section, and the order of other literature has been adjusted.
15. This tables not cited anywhere in the manuscript. Please refer to it where appropriate (perhaps in section 4.3?)
This table is also not cited in the manuscript. Please refer to it where appropriate.
Response: Thank you for your comments. In the original manuscript,The two Tables were mentioned in the second line of section 4.3.
Reviewer 3 Report
Comments and Suggestions for AuthorsThis manuscript contains the relationship between Fe concentration in soil and that in each plant tissue.
And the authors identified some relationships, however, novelty is not enough and scientific interest of readers are not high.
Major points
1) Your discussion part contains large amount of general knowledge about Fe plant nutrition.
Move 4.1 section 2nd paragraph and 4.2 section 2nd paragraph to introduction part.
2) In Figure 3, there is no statistical information, therefore, we cannot recognize your idea and description are correct or not.
3) Figure 4 is not necessary.
Minor points
1) Indicate the plant name in scientific name and add the species name.
2) In 3.1 section L6, you wrote roots > stems > leaves. However, no statistical difference was existed between stems and leaves.
3) In Figure 3c, "Stems" should be "Leaves".
Author Response
This manuscript contains the relationship between Fe concentration in soil and that in each plant tissue.
And the authors identified some relationships, however, novelty is not enough and scientific interest of readers are not high.
Thank you for your valuable comments on our article, and we sincerely appreciate the constructive comments from you. We carefully went through these comments and and summarized the scientific problems and novelty of the manuscript in detail according to your comments. As followed:
1.Scientific problems of this work
One of humanity’s greatest challenges is how to sustainably feed a large population, especially in China (Li et al. 2020; Wang et al. 2024). Triticum aestivum L. is one of the most important grain crops in the world, and increasing its yield can effectively solve the problem of food shortage caused by rapid population growth (Ray et al. 2013; Donaire et al. 2023). As crop yields continue to improve, the usage of traditional organic fertilizers to increase the availability of major nutrients (N, P, K) have been increasing. However, effective supplementation of trace nutrients necessary for plant growth (particularly for iron) has been neglected (Fei et al. 2022; Sindireva, 2023). Thus, it leads to the increasingly serious iron imbalance in the soil-plant system, which not only restricts crop yield, but also causes the problem of "hidden hunger" of trace elements in the human body (Ofori et al. 2022; Zulfiqar et al. 2024). Iron deficiency in soil-plant systems is a widespread challenge in agricultural production worldwide and a hot scientific issue that needs to be further addressed.
Two methods, leaf spraying iron fertilizer and soil micro-fertilizer, are commonly employed to resolve the symptoms of iron deficiency in Triticum aestivum L. in soils. It has been shown that the micro-fertilizer of iron carrier chelates is not affected by the pH value and Ca ion concentration of soil medium, which is of great significance for calcareous and alkaline soils (Dai et al. 2019; Wang et al. 2024). However, the threshold of soil micro-fertilizer usage to ensure the improvement of soil quality without wasting resources remains unknown.
In summary, based on the research on the biological mechanisms of soil-plant promoting nutrient efficiency and yield improvement, the authors observed the growth process of Triticum aestivum L. under different iron gradients through pot experimental systems, and further systematically explored the transport mechanism of iron in soil-Triticum aestivum L. system. The 7.2 mg/kg of iron is found to be the most favorable to the enrichment of iron in the shoot of Triticum aestivum L. plants. This study not only provides an innovative perspective and approach to reveal the promotion of nutrient efficiency plant-soil systems, but also provides a scientific theoretical basis for the study of soil-plant-human health relationship. In addition, this study provides theoretical and technical support for the development of green intelligent trace element fertilizer to promote the development of green agriculture.
2.Novelty of this work
This research delves into the phenotypic traits governing the growth of Triticum aestivum L. under varying soil iron conditions (ranging from deficient to excessive), regulated by controlling Fe2+ concentration through iron carrier chelates. It unveils the intricate transport mechanisms of iron carriers between soil and Triticum aestivum L., presenting novel insights that pave the way for advancing products and technologies aimed at enhancing nutrient efficiency and productivity.
References
Li,C.J.; Hoffland,E.; Kuyper,T.; Yu,Y.; Zhang,C.C.; Li,H.G.; Zhang,F.S.; Werf,W. Syndromes of production in intercropping impact yield gains. Nature Plants 2020, 6: 653-660.
Wang,N.Q.; Wang,T.Q.; Chen,Y.; Wang,M.; Lu,Q.F.; Wang,K.G.; Dou,Z.C.; Chi,Z.G.; Qiu,W.; Dai,J.; Niu,L.; Cui,J.Y.; Wei,Z.; Zhang,F.S.; Kümmerli,R.; Zuo,Y.M. Microbiome convergence enables siderophore-secreting-rhizobacteria to improve iron nutrition and yield of peanut intercropped with maize. Nature Communications 2024, 15:839. https://doi.org/10.1038/s41467-024-45207-0.
Ray,D.; Mueller,N.; West,P.; Foley,J. Yield Trends Are Insufficient to Double Global Crop Production by 2050. Plos One 2013, 8: e66428.
Donaire,G.; Vanzetti,L.; Conde,M.; Bainotti,C.; Mir,L.; Borrás,L.; Chicaiza,O.; Helguera,M. Dissecting genetic loci of yield, yield components, and protein content in bread wheat nested association mapping population. Euphytica 2023, 219:65. https://doi.org/10.1007/s10681-023-03195-0.
Fei,X.F.; Lou,Z.H.; Xiao,R.; Ren,Z.Q.; Lv,X.N. Estimating the spatial distribution of soil available trace elements by combining auxiliary soil property data through the Bayesian maximum entropy technique. Stochastic Environmental Research and Risk Assessment 2021, 36: 2015-2026.
Sindireva,A. Local Biogeochemical Cycles of Trace Elements in Agroecosystems of Western Siberia. Geochemistry International 2023, 61: 1048-1060.
Ofori,K.; Antoniello,S.; English,M.; Aryee,A. Improving nutrition through biofortification–A systematic review. Frontiers in Nutrition 2022, 9: 1-20.
Zulfiqar,U.; Khokhar,A.; Maqsood,M.; Shahbaz,M.; Naz,N.; Sara,M.; Maqsood,S.; Sahar,S.; Hussain,S.; Ahmad,M. Genetic biofortification: advancing crop nutrition to tackle hidden hunger. Functional & Integrative Genomics 2024, 24:34. https://doi.org/10.1007/s10142-024-01308-z.
Dai,J.; Qiu,W.; Wang,N.Q.; Wang,T.Q.; Nakanishi,H.; Zuo,Y.M. From Leguminosae/Gramineae Intercropping Systems to See Benefits of Intercropping on Iron Nutrition. Frontiers in Plant Science 2019, 10: 1-7. doi:10.3389/fpls.2019.00605.
Major points
1.Your discussion part contains large amount of general knowledge about Fe plant nutrition.
Move 4.1 section 2nd paragraph and 4.2 section 2nd paragraph to introduction part.
Response: Thank you for your comments. As suggested, We have Moved the 4.1 section 2nd paragraph and 4.2 section 2nd paragraph to introduction part, and adjusted the order of references.
2.In Figure 3, there is no statistical information, therefore, we cannot recognize your idea and description are correct or not.
Response: Thank you for your comments. We have added relevant statistical information in the form of “Table 8 ” to the revised manuscript.
3.Figure 4 is not necessary
Response: Thank you for your comments. As suggested, We have deleted “Figure 4” in the revised manuscript.
Minor points
1.Indicate the plant name inscientific name and add the species name.
Response: Thank you for your comments. As suggested, We have replaced all "wheat" in the manuscript with its scientific name "Triticum aestivum L.".
2.In 1 section L6, you wrote roots > stems > leaves. However, no statistical difference was existed between stems and leaves.
Response: Thank you for your professional comments. We have deleted the words about the accumulation order throughout the full text. The modified parts include abstract, 3.1 section L6, and conclusion.
3.In Figure 3c, "Stems" should be "Leaves".
Response: Thank you very much for your careful correction of our manuscript. We have already corrected the error.
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors have thoroughly reviewed the manuscript and it has greatly improved. It is now appropriate for publication.
Comments on the Quality of English LanguageMinor typing mistakes are present in the manuscript. Please check them before publication.
Author Response
The authors have thoroughly reviewed the manuscript and it has greatly improved. It is now appropriate for publication.
Minor typing mistakes are present in the manuscript. Please check them before publication.
Response: Thank you very much for your guidance and assistance during our manuscript revision process. We have carefully reviewed the entire manuscript and corrected typing errors, such as correcting errors in the header of Table 8. At the same time, we have also checked and revised the grammar and expression of the entire text .
Reviewer 3 Report
Comments and Suggestions for AuthorsYour response is almost a copy of previous introduction part and that is not the answer for explaining scientific value of your manuscript.
And you claimed iron regulation with chelation in soil is important, however, your manuscript described just citric acid was added in materials and methods.
Where is your scientific focusing point about iron chelation?
Author Response
Your response is almost a copy of previous introduction part and that is not the answer for explaining scientific value of your manuscript.
And you claimed iron regulation with chelation in soil is important, however, your manuscript described just citric acid was added in materials and methods.
Where is your scientific focusing point about iron chelation?
Response:
Firstly, we would like to express our gratitude for the constructive suggestions you provided during the revision process of our manuscript. We deeply regret that our initial revision failed to satisfy your expectations regarding the scientific rigor of the article. This issue primarily stems from limitations in our research approach and the breadth of our knowledge, which certainly need further enhancement.
Additionally, we appreciate your recommendations concerning the experimental design. This was our first attempt at conducting an outdoor cultivation experiment. Due to our lack of experience, some aspects of the trial preparation, such as consideration of influencing factors and the articulation of the design, were not sufficiently meticulous. We will strive to refine these elements in our future scientific research to make it more scientifically robust and rational. Your advice has indeed provided direction for our next steps in research, for which we are immensely grateful.
Regarding the iron chelating effect, our study primarily considered the addition of exogenous ferrous sulfate solution, where Fe2+ as the reduced state of iron, is readily oxidized to Fe3+ in soil solution. Fe3+ tends to form ferric hydroxide precipitates, making the iron unavailable for plant uptake. By employing the chelating action of citric acid with iron, we formed a soluble iron chelate, enhancing the mobility of iron and facilitating its diffusion to the roots for plant absorption. To make the experimental design more rigorous and scientific, we have incorporated this part into the experimental design section of the manuscript and highlighted in red.
Lastly, we sincerely thank you for your scientific comments and the instructive suggestions you have provided over the course of reviewing our article. We genuinely appreciate your assistance and support.
