Heterodichogamy, Pollen Viability, and Seed Set in a Population of Polyploidy Cyclocarya Paliurus (Batal) Iljinskaja (Juglandaceae)

Round 1

Reviewer 1 Report

The authors have not addressed my points of concern and thus I cannot recommend this article for publication. Specifically:

 

“Before all data presented in manuscript, genetic variations were estimated at various level (provenances, families), and no significant difference was found. Thus, we didn’t presented these results. Although genetic variations could exist in our plantation, flowering phenology at mating type and population level varied slightly.”

 

I don’t understand why the data is not presented here. It is an important point of concern to me and if the authors have the data, they should present it in the manuscript. Simply reporting data without showing supporting evidence to the statement is not satisfactory for publication. 

 

“Consistent heterodichogamy in other diplody species in same family has been verified previously based on data from various natural populations. Thus, all individuals were grouped together could be better to understand the flowering phenology of this species. “

 

This data is published? If yes, the reference should be added and the data described. At this stage, the author’s response has not satisfied my concern and the data cannot properly be analysed due to its heterogeneous nature. 

 

 

“According to the result using cell flow meter, tetraploidy plants occupied 95%, while di/triploidy was a small part in germplasm. Thus, the characters of tetraploidy could represent the status of population. “

This is not a satisfactory answer. The authors seem to think that because only 5% of the population differs in term of ploidy, it is ok to use the mix data and ignore the importance of the ploidy change and its implication it may have on the fertility outcome. One conclusion of the article is that low fertility could be caused by the tetraploid nature of the plants. This could easily be tested by separating the dataset into 2 populations: tetraploid vs diploid. Could the diploid plants have better fertility level than tetraploids?

Author Response

Dear reviewer, 

     Thank your for your comments.

     1. For the effects of genetic variation  on flowering phenology, we add the correlation analysis of plant origin with flowering expressions, Please check it in discussion 4.1. Because of huge data, so we can't present all the information in detail. If you still have question about this point, just tell us, we will do our best to illustrate clearly.

     2. For the conclusion involving low pollen fertility, explaination as follows:

     As you pointed out here, we can’t ignore the importance of the ploidy variation in population. Thus, we just speculate the possibility of low fertility based on previous reports on tetraploid plants. However, this speculation should be verified, this is our next work.

     As we described in this paper, the age of population is at the juvenile stage. In 2018, only 73.5% flowering plants, including 16.3% F type, were observed (Table 1). In which, only 5 diploid plants were observed with a few male flowers. In addition, flowering plants are unstable in each year. Thus, we can’t verify this speculation until enough pollens produced.

    

     Yours sincerely,

     Xiangxiang Fu

Reviewer 2 Report

I enjoyed reading the manuscript. This paper described complicated details of protandry and protogyny in a woody plant, the result of which may be interesting to evolutionary biologists in plant ecology areas.

I found following minor problems in the manuscript, so please improve the expression, if necessary. 

L18-19:

This study aims to profile the flowering phenology and the efficacy of pollen dispersal as well as will also elucidating the mechanism of low seed success in the population.

 I could not understand this sentence, may be typological errors?

 

L29 sexual ratio: 

Sexual type ratio may be better, because sexual ratio is easily misunderstood as sex ratio.

L42 a polymorphic phonologic sexual system:  Phonologic might be replaced phenological??

 

L48 To avoid frequency-dependent selection, the population has evolved to have a 1:1 morph ratio [5].

 I think “To avoid” seems strange. Rather, equal sex ratio is a result of negative frequency-dependent selection on sex ratio.

 

Table 3: “Observation datePollen density” may be “Observation date Pollen density”.

 

Line 303~: Alternatively, adaptive interpretation considers that female-bias favors the production of more seeds for species survival under adverse conditions, like nutrient shortage and changing climatic factors (dry, cold, etc.).

This sentence may be misleading in the light of gene centric view in that natural selection functions in a gene or at best individual level, but not in species level.

Author Response

Dear reviewer,      

       Thanks a lot for your comments.

       Your concerns  were respond as follows:

L18-19: This study aims to profile the flowering phenology and the efficacy of pollen dispersal as well as will also elucidating the mechanism of low seed success in the population.  I could not understand this sentence, may be typological errors?

         R: This sentence has revised to “This study aims to profile the flowering phenology and the efficacy of pollen dispersal as well as   elucidate the mechanism of low seed success in the population” (L18-19)

         2. L29 sexual ratio: Sexual type ratio may be better, because sexual ratio is easily misunderstood as sex ratio.

         R: Done, see line 29. We used “mating type ratio” instead of “sexual ratio”.

         3. L42 a polymorphic phonologic sexual system:  Phonologic might be replaced phenological??

         R: A mistake. Here is “phenological”.

         4. L48 To avoid frequency-dependent selection, the population has evolved to have a 1:1 morph ratio [5]. I think “To avoid” seems strange. Rather, equal sex ratio is a result of negative frequency-dependent selection on sex ratio.

          R: This statement is cited by many publications. Indeed, I have no idea for this point. Could you give us a suggestion?  

          5. Table 3: “Observation date Pollen density” may be “Observation date Pollen density”.

          R: This is the problem of typesetting. It is adjusted.

          6. Line 303~: Alternatively, adaptive interpretation considers that female-bias favors the production of more seeds for species survival under adverse conditions, like nutrient shortage and changing climatic factors (dry, cold, etc.).

This sentence may be misleading in the light of gene centric view in that natural selection functions in a gene or at best individual level, but not in species level.

         R: Done, this sentence has been revised “Alternatively, adaptive interpretation considers that female-bias could favor the production of more seeds for gene/individual survival under adverse conditions……..”

        Again, if you have any question about our work, tell us, and we will do our best to improve it.

        Yours,

        Xiangxiang Fu

Round 2

Reviewer 1 Report

The authors have addressed my comments

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The article from Mao et al. aims to investigate the flowering phenology in Cyclocarya paliurus. The article is easy to follow, the experiments are well designed and describe. The article is very descriptive and will be of importance to the field. I think the manuscript will benefit if some images of Cyclocarya paliurus inflorescences representing the three groups (flowering group, monoecious group and unisexual group) are added. From the data presented here, data from individual samples are pools based on their group. However, it seems that the population is composed of 53 families from 8 provenances, likely causing genetic variations between individuals. Also, the population has individuals with different ploidy level, which again complicate the interpretation of the data. My impression is that at the current stage, the population is divided based on phonologic criteria. Genetic variation likely plays a role in the phenotypes (especially regarding pollen density and viability) describes in this manuscript and it is important that the authors address these points – e.g. repeating the analysis but this time by ranking the individuals based on their ploidy and/or genetic background (example using the 8 provenances). 

Reviewer 2 Report

I was looking forward to reading this study, but the English writing is so poor that I ended up not wanting to review this paper.  The authors should look at the study (which must be cited) of T. Fukuhara and S. Tokumaru on "Inflorescence dimorphism, heterodichogamy and thrips pollination in Platycarya strobilacea (Juglandaceae)" Annals of Botany 2014. It deals with a related species of Juglandaceae and could provide a model for how to improve the presentation of the data. Or they need to pay someone to get the manuscript into proper English.