Allometric scaling theory has previously been used to estimate the functional relationship between two biological variables. In addition to parameter estimation, deviations from the general scaling relationship can be used to create hypotheses. Here, I explore deviations from the allometric scaling pattern for plant and floral size within the genus Collinsia on three levels: among species, within species, and among populations of a single species. Collinsia species are self-compatible annual herbaceous plants that have been shown to vary in floral size, autonomous fruit production, and estimated mating system. I quantified the amount of variation in characteristics related to plant mating systems: floral size and autonomous fruit production in a pollinator-free environment and used variation and scaling deviations to generate expectations about environmental selection pressures. I found that the scaling relationships differed on each of the three levels and that deviation from the general floral size-plant size relationship is common within this genus. The among-species regression explained only 20% of the variation in floral size, and species- and population-level regressions explained even less. The four species for which I obtained controlled environment estimates of vegetative and floral trait in this study differed significantly in autonomous fruit production, floral size, and plant size, while populations of C. heterophylla differed in floral and plant characteristics, but not autonomous fruit production. In addition, variation in plant size characteristics was 50-66% greater than variation in floral size characteristics suggesting selection to reduce variation in floral size and flexibility in plant size. Autonomous fruit production was correlated with floral size in C. tinctoria, with floral number in C. verna, and uncorrelated in C. heterophylla suggesting that the ability to self-fertilize varies among species. Using a comparative method and investigating factors correlated with plant mating system, such as floral traits, across a group of closely related species provides new insights into factors affecting their variation.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-04202005-221902 |
| Date | 07 June 2005 |
| Creators | Hanley, Kristen Marie |
| Contributors | Dr. Tia-Lynn Ashman, Dr. Stephen Tonsor, Dr. Valerie Oke, Dr. Susan Kalisz |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-04202005-221902/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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