The Role of Seed Characteristics on Water Uptake Preceding Germination
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
This study has summarized the relationship between seed water absorption and seed characteristics.
Some minor corrections are as follows:
1. Recently, many studies have been conducted on physical dormancy of seeds. Accordingly, the structure and mechanism of various water gap complexes have been reported. In addition, types I, II, and III of physical dormancy have been reported. Therefore, it would be good to supplement the contents of these parts.
2. Various contents have been organized in the text. In order to increase visibility, it would be better to express it by adding a table.
3. References: Many parts, such as abbreviations or full names of journals and italics of scientific names, need to be revised. Please review and revise them one by one.
Author Response
Please see the attached Reviewer 1 comments and our response. Our revisions to Reviewer 1 can be seen in the revised manuscript in the yellow highlighted text. Thank you very much.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Comments and Suggestions for Authors
Comments:
The manuscript is a review of an interesting topic regarding seed biology and imbibition, an essential process for germination and seedlings emergence (and therefore for the establishment of crops and plants in general). A strength of the manuscript is that it provides a very good literature review on the subject, raising some interesting points.
However, there are some aspects that could be considered to improve the quality of the work:
Regarding the effect of seed size, there is confusion between the effects on impermeability, imbibition rate, and the amount of water absorbed. While it is clear that smaller seeds imbibe faster (due to their higher surface-to-volume ratio), it is not clear that smaller seeds are more permeable (or less impermeable) and larger seeds are more impermeable (this depends more on the species). On the other hand, the percentage of water absorbed varying between large and small seeds could be related to the relative proportion of seed structures (testa, embryo, endosperm) among seeds of different sizes. This could be considered or discussed.
Throughout the manuscript, examples of studies on different species are given, but in most cases, the scientific names are not provided (they should be indicated at least the first time the species is mentioned). On the other hand, scientific names appear that are not in italics.
More figures could be incorporated into the text, especially regarding the dynamics of imbibition (how water enters different seeds). It would also be useful to refer to the different forms or techniques used to study imbibition.
When discussing seed dormancy and its relationship with imbibition, the relationship between physical dormancy and lack of imbibition is quite clear. However, when referring to physiological dormancy, the conclusions drawn are quite questionable. For example, saying “This suggests that the promotion and delay of germination in seed by GA3 and ABA, respectively, is regulated by controlling water uptake of the embryo tissues in the seed” is confusing because the effect of these hormones would be indirect. What they do is affect the elongation capacity of the embryo cells, and with that, the ability to absorb water is ultimately affected, meaning the effect of these hormones on imbibition is indirect. In fact, the imbibition process in phases 1 and 2 of seed germination (with phase 1 being rapid imbibition and phase 2 being the plateau phase observed in seeds before radicle emergence) is basically the same in dormant and non-dormant seeds (physiological dormancy), what changes is how long phase 2 lasts.
The importance of genotype in the permeability of seeds of a species is raised, but the effect that the maternal environment, in which the seed develops, can have on seed permeability is missing. This is an interesting aspect given the climate change scenario. For example, will the increase in temperature during seed development affect its permeability? (the literature indicates that in many cases this happens…)
Other observations:
- Line 75: In this paragraph, the entry points of water in scarified seeds are compared, but only in one of the examples is the type of scarification used mentioned. It would be good if the type of scarification used is mentioned in each example.
- Lines 169-172: The text of this last sentence starts with “Similarly,…”, however, its content refers to a trend opposite to what is observed in the other cited cases.
- Lines 186 and 187: I don’t think the word “exchange” is the best in this case, it should probably be imbibition or absorption.
- Line 250: Should be “32.0 and 34.2%” or “32 and 34”.
Author Response
Please see the attached Reviewer 2 comments and our response. Our revisions to Reviewer 2 can be seen in the revised manuscript in the green highlighted text. Thank you very much.
Author Response File: Author Response.docx
Reviewer 3 Report
Comments and Suggestions for Authors
Comments for author File: 
Comments.pdf
Author Response
Please see the attached Reviewer 3 comments and our response. Our revisions to Reviewer 3 can be seen in the revised manuscript in the gray highlighted text. Thank you very much for your time to provide such an excellent review of our manuscript. We would like to offer you co-authorship if you are open to this. Thanks again, Karen Tanino
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
Comments and Suggestions for Authors
I think this revised version of the manuscript improved significantly with respect the previous version. However, I suggest some minor changes before publication.
Line 89: says: “…water entered thermally into scarified seed…”, please check, should it be “water entered into thermally scarified seed”
Figure 2. I suggest that each imagine include the imbibition time (0 h, 6 h, 12 h, 24 h…) instead of the letters (i), ii), iii) …). In that way, the figure legend could be more concise and simpler.
Line 313: please be more specific about what aspect of “seed water absorption” are you referring. Is it the amount of water absorbed by the seed? Or is it the absorption rate?
Line 333 to 341. Similar to the previous comment, what do you mean by water uptake capacities (permeability, rate, volume absorbed, water attraction?)
Line 357: specify that “hormone-mediated seed dormancy” corresponds to physiological dormancy (PY)
Line 421: Please, clarify the meaning of the % when expressing water uptake, is it % of seed mass increase?, the percentage of seed water content after imbibition?
Line 435 to 439. I think this paragraph should be moved to the beginning of this section, after the first paragraph.
Line 478: please specify what aspect of “water uptake” was modified by priming (rate?, volume?)
Line 440 to 470: Although I understand this text may be added in response to a reviewer´s comments, I think it has more information than necessary. It could be more concise.
Line 500 to 502: “physiological dormancy is regulated through the modulation of water uptake, where ABA inhibits this process, while GA3 enhances.” I do not agree with this sentence, I think is misleading. Physiological dormancy is regulated by the balance of ABA and GA (no GA3), no by the modulation of water uptake. The effect of hormonal balance is in the embryo growth potential and resistance of structures that surround it (ej. endosperm). I think the sentence should be removed.
Author Response
We would like to sincerely thank again the reviewer for taking the time to review our manuscript. We greatly appreciate your valuable comments and suggestions. In response, we have made the necessary revisions, and to facilitate easy identification, all changes based on your recommendations have been highlighted in blue.
Comment 1: Line 89: says: “…water entered thermally into scarified seed…”, please check, should it be “water entered into thermally scarified seed”
Response 1: Yes it should be water entered into thermally scarified seed. It has been changed.
Comment 2: Figure 2. I suggest that each imagine include the imbibition time (0 h, 6 h, 12 h, 24 h…) instead of the letters (i), ii), iii) …). In that way, the figure legend could be more concise and simpler.
Response 2: The letters (i),(ii),(iii) has been kept, and the imbibition time has been kept after the letters. The legend has been changed to Staining of the Gleditsia sinensis seeds. i) Control seed; staining after ii) 6h; iii) 12h; iv) 24h; v) 48h; vi) 72h.
Comment 3: Line 313: please be more specific about what aspect of “seed water absorption” are you referring. Is it the amount of water absorbed by the seed? Or is it the absorption rate?
Response 3: It has been changed to amount of water absorbed by seed to be specific.
Comment 4: Line 333 to 341. Similar to the previous comment, what do you mean by water uptake capacities (permeability, rate, volume absorbed, water attraction?)
Response 4: Here water uptake capacities meant water absorption.
Comment 5: Line 357: specify that “hormone-mediated seed dormancy” corresponds to physiological dormancy (PY)
Response 5: PD has been added in the brackets after hormone-mediated seed dormancy.
Comment 6: Line 421: Please, clarify the meaning of the % when expressing water uptake, is it % of seed mass increase?, the percentage of seed water content after imbibition?
Response 6: Here, the percentage of water uptake refers to the amount of water taken up relative to the initial seed mass and is clarified.
Comment 7: Line 435 to 439. I think this paragraph should be moved to the beginning of this section, after the first paragraph.
Response 7: The sentence has been moved.
Comment 8: Line 478: please specify what aspect of “water uptake” was modified by priming (rate?, volume?)
Response 8: The water uptake represents the increase in moisture content on fresh weight basis and has been included.
Comment 9: Line 440 to 470: Although I understand this text may be added in response to a reviewer´s comments, I think it has more information than necessary. It could be more concise.
Response 9: We appreciate Reviewer 2’s suggestion. However, although we have tried, we find it difficult to significantly reduce the information.
Comment 10: Line 500 to 502: “physiological dormancy is regulated through the modulation of water uptake, where ABA inhibits this process, while GA3 enhances.” I do not agree with this sentence, I think is misleading. Physiological dormancy is regulated by the balance of ABA and GA (no GA3), no by the modulation of water uptake. The effect of hormonal balance is in the embryo growth potential and resistance of structures that surround it (ej. endosperm). I think the sentence should be removed.
Response 10: Yes, good catch and good point. We agree and the sentence has been removed.
