Plasticity of Reproductive Traits in Response to Pollen-Limited Fruit Initiation in an Annual Plant

Mount, Nathaniel James Hamnett

Plasticity of Reproductive Traits in Response to Pollen-Limited Fruit Initiation in an Annual Plant

dc.contributor.advisor	Harder, Lawrence
dc.contributor.advisor	Rogers, Sean
dc.contributor.author	Mount, Nathaniel James Hamnett
dc.contributor.committeemember	Reid, Mary
dc.contributor.committeemember	Samuel, Marcus
dc.date.accessioned	2023-09-27T19:08:24Z
dc.date.available	2023-09-27T19:08:24Z
dc.date.issued	2023-09-26
dc.description.abstract	Pollination is a highly uncertain and variable process, and insufficient pollination commonly limits seed production and siring success by flowering plants. Due to this unpredictability, plants, particularly those with annual or otherwise semelparous life-histories, could benefit from phenotypic plasticity in their reproductive growth and function that enhances the overall likelihood of pollination and provides some compensation for pollen limitation. To test this hypothesis, three hand-pollination experiments were conducted using a rapid-cycling variety of Brassica rapa to determine whether limited pollination stimulated plastic responses that could increase seed production relative to the fecundity that would be realized in the absence of plasticity. Plants on which a limited fraction of flowers had been pollinated exhibited many differences from well-pollinated plants. Compared to well-pollinated plants, pollination of 25% of a plant’s flowers reduced fruit production, indicating pollen limitation. In contrast, fruit number did not vary with pollination if at least 50% of flowers were pollinated, indicating resource limitation. In response to pollen limitation, poorly pollinated plants produced more flowers than well-pollinated plants, which should increase their overall pollination success. Neither pollen number per flower on terminal racemes nor its siring ability varied with pollination success. However, plants with few developing fruits produced more ovules in distal flowers of their axillary racemes and more seeds per distal fruit on all racemes compared to plants with many developing fruits. Pollen-limited plants with relatively few seeds overall produced larger seeds, which should enhance seed germination and seedling establishment. Overall, pollen-limited plants also opened fewer flowers per day, extending their total flowering period and exposure to pollinators. Nevertheless, pollen-limited plants opened more flowers per day during late flowering, which increased the number of flowers displayed simultaneously and should enhance pollinator attraction. These results indicate that, rather than being helpless against pollen limitation, plasticity of reproductive characteristics allows annual plants to compensate, at least partially, for low per-flower pollination probability.
dc.identifier.citation	Mount, N. J. H. (2023). Plasticity of reproductive traits in response to pollen-limited fruit initiation in an annual plant (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.
dc.identifier.uri	https://hdl.handle.net/1880/117268
dc.identifier.uri	https://doi.org/10.11575/PRISM/42110
dc.language.iso	en
dc.publisher.faculty	Graduate Studies
dc.publisher.institution	University of Calgary
dc.rights	University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subject	Pollen-Limitation
dc.subject.classification	Ecology
dc.subject.classification	Botany
dc.title	Plasticity of Reproductive Traits in Response to Pollen-Limited Fruit Initiation in an Annual Plant
dc.type	master thesis
thesis.degree.discipline	Biological Sciences
thesis.degree.grantor	University of Calgary
thesis.degree.name	Master of Science (MSc)
ucalgary.thesis.accesssetbystudent	I do not require a thesis withhold – my thesis will have open access and can be viewed and downloaded publicly as soon as possible.