Studying Evolutionary Constraints on an Invariant Floral Trait in Wild Radish Raphanus raphanistrum
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Authors
Fergus, C. Emi
Issue Date
2001
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
Traits that appear to be fixed either in a population or across taxa must be
maintained by some mechanism. In the plant Raphanus raphanistrum, the trait of zero
anther exsertion, which is a high correlation between filament and corolla tube lengths, is relatively fixed across populations and believed to be critical to plant fitness. Traits
linked to zero anther exsertion that affect plant fitness, would be developmental
constraints and would restrict phenotypic variability. The experiment utilized artificial
selection, to create phenotypic variability, and field observations of natural pressures to
test for evolutionary influences on anther exsertion. Female fitness (number of seeds produced) was measured to determine if plant fitness was affected by female traits linked with anther exsertion. Viable pollen counts were made twice through the season to observe possible developmental constraints acting through the male fitness side.
The results found no significant relationship between the different degrees of
anther exsertion and female fitness, indicating that traits correlated with anther exsertion
do not affect female fitness. The pollen viability results for the early season count found a significant relationship between amount of viable pollen and plant treatment. However, in the late season count there were no statistically significant relationships. The data suggests that viable pollen may be linked to zero anther exsertion for younger plants, but as the plants age the relationship diminishes.
Description
vi, 24 p.
Citation
Publisher
Kalamazoo College
License
U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder.