The Relationship between Shape and Size of Diaspores Depends on Being Seeds or Fruits
Round 1
Reviewer 1 Report
An attempt was made in the study to determine the effect of size on the shape of seeds and fruits. The Authors relied on an available database of the average dimensions and volume of seeds/fruits of many different plant species. This is one of the strengths of this study because the results can be generalized and used in further research, directly or indirectly related to the topic. The Authors used certain simplifications. Firstly, seed volume was determined based on the volume of an ellipsoid, and the average values of the three main dimensions were used. Secondly, seed/fruit shape was described as deviations from an ideal sphere where all three dimensions are identical. It should be noted, however, that even seeds of the same variety may differ in volume and shape, which should be taken into account in further research.
The manuscript is generally well-organized and formatted. The keywords should be modified to reflect the manuscript’s contents without repeating the words already included in the manuscript’s title. I have no concerns regarding the Introduction section, which contains the necessary background information. In the Materials and Methods section, in line 84, the citation is placed at the end of the sentence, thus suggesting that it refers to the presented numerical values. However, I could not find them in the cited paper, therefore the citation should be placed after the word “…hispanica”. In the Results section, in Table 1 caption, the unit of sphericity is mm2 – please note that sphericity is a dimensionless quantity (possibly expressed as a percentage). Please consider reducing the number of decimal places/significant digits (e.g. to two) in the Table. The information in lines 123 and 139 suggests that seeds are larger than fruits, which is generally not true because seeds are part of the fruit – please be more precise. I have no major concerns regarding the remaining sections of the manuscript.
Author Response
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Author Response.pdf
Reviewer 2 Report
The study delves into an old topic already analysed in several studies published year ago. The authors use the idea of seed sphericity to described them, instead of seed mass, which is not really novel. In the introduction the authors claim that seed weigh cannot be taken as a measurement of seed size, an asseveration that is very right. However, authors also claim that seed ‘size quantification was done weighing seeds not only in the review cited but overwhelming in studies of ecological and functional correlates of seed size’. However This, being possibly correct is not exact as there are revisions other than that of Harper (1970) published later that use other metrics fro seed size. Examples of those papers more recent than 1970 are quoted below and they should be taken into consideration both in the introduction and in the discussion of the results.
Thompson, K., Band, S. R, and Hodgson, J. G. 1993. Seed size and shape predict persistence in soil. Functional Ecology 7: 236-241.
Pérez-Fernández MA, Lamont B, Marwick AL, Lamont W. (2000) Germination of seven exotic weeds and seven native species in south-western Australia under steady and fluctuating water supply. Acta Oecologica 6: 323-336.
Cerdá A, García-Fayos P (2002) The influence of seed size and shape on their removal bywater erosion. Catena 48:293-301.
Pérez-Fernández MA, Gómez-Gutiérrez JM, Martín-Berrocoso AM, Mann Reinier (2002). Effect of seed shape and size on their distribution in the soil seed bank. Journal of Mediterranean Ecology 3: 11-17.
In lines 48 to 52 the authors state ‘Useful as these descriptions might be to identify 48 the species to which seeds belong, the result was 164 different descriptions for 193 species, almost 49 one per species, which is hardly useful to investigate the ecological, functional or evolutionary 50 relevance of seed shape. Things tend to get worse when descriptions of seed shape made by different 51 authors are compared [11]’
The tone seems a bit contemptuous towards descriptions of seeds. Those description have been and still are, needed in identification of seeds. I would like to ask the authors to acknowledge the value of the afore mentioned descriptions, and to justify the need for their study in a more positive and constructive way, without putting down the value of the previous work of other researchers.
In lines 57 to 62 the authors propose a method to determine seed size exactly similar to that proposed by Thompson et al in 1993. I cannot see the novelty of the method.
The scientific hypotheses are not clearly stated.
M&M
Although fruits and seeds both are diaspores, they nature differ in that the later might rend more than one new plant after germination and more importantly, fruits’ water content are usually greater than that in seeds; consequently, they size, shape and mass change over time, so does their ecological meaning unless all the used fruits are dry (nut type). This end needs to be expanded upon.
Even though they give the link to the data set it is needed that the data shown here are organize by indicating what species have fruits and which ones have seeds. The botanical family they belong to would also be welcome as both bits of information bring ecological and biological information about the propagules under consideration.
The authors claim that they results are similar when using actual data and when thickness was estimated. Unfortunately, in the material and methods this is not clearly explained and one ends up with the feeling that only estimated T values were used. Please, explain this part of the methods thoroughly.
The discussion is rather poor and in its current form, it only represents a summary of the results. This might have to do with the poor definition of hypotheses. Even though the authors refer to the biological meaning of seed size, nothing is further discussed at this regard.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors have made a great job amending the original manuscript, what I acknowledge.
I’m happy with the answers provided. Although I disagree in the comments they make on the selected references in regards the use of dimensions of seeds. I will not go further into it as the discussion is basically semantic and readers of all these papers will find the actual differences and similarities.
The only aspect the authors still have to deal with is the discussion. No matter what kind of submission they have selected, any kind of paper, particularly those experimentally based, as this is the case, regardless its length have to have hypothesis and conclusions. The authors claim that it is enough to present the questions they want to answer and for this very same reason, it wouldn’t be difficult to produce actual hypothesis. Please, take this into account. In regards discussion, it cannot be a summary of the results, but the results must be explained and compared with the already existing literature. Please, attached to the internationally accepted scientific method.
Author Response
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Author Response File: Author Response.pdf
Round 3
Reviewer 2 Report
Thanks for the modifications included in your reviewed paper. However, hypotheses are not yet included. The conclusions also need a polish, as they remain to be a summary of the results.
Thanks
Author Response
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Author Response File: Author Response.pdf
