Variation and Phenotypic Selection on Within-Inflorescence Gradients of Floral Traits
Date
2017-12-22
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Abstract
The modular nature of inflorescences allows within-individual floral variability as a feature of plant phenotypes. The widespread expression of within-inflorescence floral “gradients” among Angiosperms could result from among-metamer resource competition (‘plasticity’), or from intrinsic, positional effects (‘architectural effects’). I tested these hypotheses with Delphinium glaucum using the methods of functional data analysis, which have not been applied previously in this context. These methods depict plant phenotypes as functions that vary systematically among flower positions. The analyses revealed that: 1) among-metamer competition for resources was associated with some floral trait gradients; and 2) gradients of many floral traits experience phenotypic selection through female success. These results reveal alternative ecological and evolutionary interpretations of inflorescence phenotypes than those based on analyses that ignore within-inflorescence variation and instead consider only mean floral phenotypes. They also demonstrate that both plasticity and architectural effects can affect the expression and evolution of within-inflorescence floral gradients.
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phenotypic selection, plasticity, Delphinium glaucum, architectural effects, scalar-on-function regression, function-on-scalar regression, functional data analysis, intra-individual variation, inflorescence, evolution, floral trait gradients
Citation
Clocher, I. C. (2017). Variation and phenotypic selection on within-inflorescence gradients of floral traits (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.