Therefore, increasing resource limitation could increase variability in seed set among fruits Fig. Resource-driven, density-dependent effects of ovule number on seed set did not diminish with increasing levels of pollen limitation, as expected if whole plants were physiologically integrated.
Therefore, persistence of the resource-driven relation between ovule number and seed set under increasing pollen limitation can then be understood in the context of resource compartmentalization. Considering that all the study factors play a role in limiting seed set in raspberry, we propose that seed production in modular plants can be frequently subject to a mosaic of reproductive limits, with flowers in some modules limited by pollen, others by resources, and others by ovule number.
This latter overlooked factor clearly sets a sharp upper limit to flower seed production Figs. Even interactions can exist between these factors, as shown here that the magnitude of the density-dependent effect of the number of ovules could depend on the plant resource status.
This mosaic of reproductive limits might also replicate at the within-flower level in plants with apocarpic ovaries, a flower sexual morphology that allows differential resource allocation and differential fertilization of ovules in different carpels. According to this integrative perspective, plants should be viewed as mosaics in which different factors, and interactions between them occurring within integrated physiological units, can limit the seed production of different plant modules.
Instead, our perspective agrees with the view that individual plants can be seen as mosaics exhibiting high intra-individual phenotypic variation because a multiplicity of factors affect independently different modules Herrera, Ovule number appears to be the overriding, but not the only, factor affecting the number of seeds at the flower level in raspberry.
The strong and positive relation between ovule number and seed set in raspberry may relate, to some extent, to the resource allocation patterns of this plant, where resources are supplied mainly at the inflorescence level and investment in pulp or other ancillary structures is strongly dependent on the number of seeds.
More generally, this study proposes that several factors i. Hence, an improvement in each of these factors will commonly improve reproductive success.
Future studies on the limits of plant reproduction should focus on the relative contribution of these different factors i. It would be also worth exploring whether the degree of physiological integration among flowers in lineages with different plant architectures and life histories conditions the way ovules, resources and pollination affect seed production.
The scenario here proposed, according to which seed production is limited simultaneously by all these factors, might get diluted, resembling the dichotomous response, in lineages with more physiologically integrated plants e.
Adopting a modular perspective of plant reproduction, where plants are viewed as mosaics in which different factors and their interactions within integrated physiological units affect seed set, will increase our understanding of the limits on seed production. The authors thank L. Harder, C. Morales, A. Garibaldi, A. We also thank G. Rentschler and U. Rittershofer, the owners of the Paso Flores farm Bariloche , for allowing us working in their raspberry field.
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests The authors declare that they have no competing interests. Author Contributions Marina M. Marcelo A. Data Availability The following information was supplied regarding data availability:.
National Center for Biotechnology Information , U. Journal List PeerJ v. Published online Jul Marina M. Strelin and Marcelo A.
Author information Article notes Copyright and License information Disclaimer. Corresponding author. Strelin: ra. Received Apr 19; Accepted Jul This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed.
This article has been cited by other articles in PMC. Raw data used in the analyses corresponding to objectives 1, 2 and 3. Abstract Background A classical dichotomous perspective proposes that either pollination or plant resources limit seed production. Methods We first assessed if ovule number affected the fraction of ovules that develop into seed i.
Results Within inflorescences, flowers with more ovules set a larger fraction of seeds. Discussion Results reveal the importance of ovule number as an overriding factor affecting seed set. Introduction Seed production can be affected by a diversity of factors acting during flower and fruit development Primack, Open in a separate window.
Figure 1. Schematic representation of ovule-, pollination-, and resource-limitation of seed production by individual flowers given different levels of physiological integration, which decreases from A i. Field sampling We haphazardly chose 25 young ramets produced during the sampling season and 25 old ramets from the previous season distributed over the entire field. Results Variance partitioning of ovule and seed number The partitioning of variance in ovule number among flowers within inflorescences, among inflorescences within ramets, and among ramets depended on ramet age.
Figure 2. Variance components, as a percentage of the total, of ovule number among flowers within inflorescences, among inflorescences within ramets, and among ramets for young and old ramets.
Figure 3. Variance components, as a percentage of the total, of seed number among flowers within inflorescences, among inflorescences within ramets, and among ramets for young and old ramets that were excluded from or exposed to pollinators. Effect of modularity on the relation between ovule number and seed set objective 1 Even though we found an overall positive effect of ovule number on seed set Fig.
Figure 4. Effects of ovule number, pollination treatment excluded from or exposed to pollinators and ramet age on seed set. Table 1 Results of partial-effect analyses of the deviance for different models designed to address the three objectives of this study. Effects of ovule number, plant age and pollination treatment on seed set objective 2 For the 1, flowers we examined, an average of Effect of branching order and plant age on ovule number and seed set objective 3 All fixed effects in the first model addressing objective 3, i.
Figure 5. Discussion This study reveals the importance of ovule number as an overriding factor affecting the number of raspberry seeds, so that the higher the number of ovules per flower the higher the proportion of ovules becoming seed. Variation in seed set as a direct consequence of variation in ovule number Our results indicate a clear distinction in the way resources are allocated to ovules and seeds.
A modular perspective of the relation between ovule number and seed set The positive density-dependent effect of ovule number on seed set occurs basically among flowers within inflorescences and suggests that, within well-pollinated inflorescences, flowers with more ovules and embryos become stronger sinks for locally limiting resources Fig.
The interplay between ovule number, resources and pollination Our findings support the hypothesis that plant resource status is an important factor mediating the relation between ovule number and seed set. A mosaic of reproductive limits Considering that all the study factors play a role in limiting seed set in raspberry, we propose that seed production in modular plants can be frequently subject to a mosaic of reproductive limits, with flowers in some modules limited by pollen, others by resources, and others by ovule number.
Conclusion Ovule number appears to be the overriding, but not the only, factor affecting the number of seeds at the flower level in raspberry. Click here for additional data file. Acknowledgments The authors thank L. Additional Information and Declarations Competing Interests The authors declare that they have no competing interests. Dissecting the causes of variation in intra-floresence allocation in a sexually polymorphic species, Fragaria virginiana Rosaceae American Journal of Botany.
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Influences of floral variation on pollen removal and seed production in wild radish. Ecology 71 : — Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide. Sign In or Create an Account. Sign In. Advanced Search. Search Menu. Article Navigation. Close mobile search navigation Article Navigation. Volume Article Contents Abstract.
Materials and Methods. Supporting Information. Sources of Funding. Contributions by the Authors. Conflict of Interest. Literature Cited. Ovule and seed production patterns in relation to flower size variations in actinomorphic and zygomorphic flower species.
Jun Mochizuki , Jun Mochizuki. Oxford Academic. Tomoyuki Itagaki. Yuta Aoyagi Blue. Masaya Ito. Satoki Sakai. Editorial decision:. Corrected and typeset:.
Select Format Select format. Permissions Icon Permissions. Abstract Zygomorphic flower species tend to show lower flower size variation than actinomorphic flower species. Angiosperms , ovule number variation , ovule size variation , seed size variation , selection through pollinators.
Table 1. List of the 49 species studied. Sampling site. Sampling habitat. Open in new tab. Table 2. Response variable. The cotyledon is highly packed with starch. In an ovule, the parenchymatous cells named nucellus store some food energy that is used by the embryo sac for the development of the ovule. The micropile is a tiny opening on the surface of an ovule or a seed. The difference of the seed micropile and the ovule micropile is brought about by their different functions.
In an ovule, the micropile provides an entrance of the pollen into the ovule structure in order to carry out the process of fertilization. When it comes to the seed structure, the micropile acts an entry point of water and air that are utilized in the process of germination. In a seed the embryo is the most important part because its cells differentiate and grow into the various tissues that constitute the plant.
In the embryo sac is where the egg cell which fuses with the pollen to form a zygote is found. A funicle is a bunch of fibres that attach one part of a plant to another. The funicle in an ovule attaches the ovule to the placenta. In the case of a seed, the funicle is referred to as a stem.
The stem attaches the seed to the fruit. From these illustrations above, it is evident that the ovule and the seed have general differences. Difference Between Similar Terms and Objects. MLA 8 Ewan, Dart. Name required. Email required. Please note: comment moderation is enabled and may delay your comment. There is no need to resubmit your comment.
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