Susko, David , Clubb, Michelle .
Patterns of Seed Ontogeny Reflect Plant Breeding System in Brassicaceae.
We examined the relationship between breeding system and patterns of ovule fate for multiple species of mustards growing in sites in southwestern Ontario and southeasten Michigan. Each species has multi-ovulate, linear fruits, in which the relative position and developmental stage of each ovule could be determined. We found that most autogamous species tended to mature more seeds at the basal ends of fruits than at the tips, while most xenogamous species matured more seeds in centrally located ovule positions than at either end of the fruit. Also, using a hand-pollination experiment with the self-compatible, invasive perennial weed Hesperis matronalis, we were able to manipulate the respective patterns of seed maturation and abortion. In general, cross-pollinated plants produced the most mature seeds at the tips of fruits, whereas self-pollinated individuals matured the most seeds in the central regions of fruits. Analysis of pollen tube development within pistils using fluorescence microscopy revealed a weak correlation between ovule position and probability of fertilization, with proximal ovules being more likely to be fertilized than distal ovules. Our results indicate that patterns of seed maturation and abortion are related to breeding system through the latter’s influence on intrafruit resource and fertilization gradients. In the future, such patterns may be useful as descriptive tools for a) identifying possible qualitative differences in breeding systems and b) assessing whether invasive plant species have more variable/flexible breeding systems than do native plant species.
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1 - University of Michigan Dearborn, Department of Natural Sciences, Dearborn, Michigan, 48128, USA
2 - University of Michigan-Dearborn, Natural Sciences, Dearborn, MI, 48128, USA
Presentation Type: Poster:Posters for Sections
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM