The Development and Use of Unique Molecular Markers to Study Pollen Dispersal Within Two Plant Species across Diverse Habitats in the New York Metropolitan Area
Pollen dispersal is the most important component of gene flow in plants. However, few studies have investigated pollen dispersal patterns among dissimilar sites and no studies have compared methods for modeling these patterns. Additionally, assessing pollen dispersal is complicated because of the time and monetary cost of current methods for tracking individual pollen and the use of contrasting methods for modeling empirical dispersal data. To address these issues, I investigated pollen dispersal in a wind-pollinated (Amaranthus tuberculatus (Moq.) J.D. Sauer) and an insect-pollinated species (Solanum lycopersicum L.) at four sites in the New York metropolitan area. I identified and optimized three molecular markers for A. tuberculatus and two for S. lycopersicum. Using these markers, 100% of the genotyped A. tuberculatus seeds were assigned to the experimental pollen donors and 97% of the genotyped S. lycopersicum fruits were assigned to the experimental pollen donors, while the remaining 3% were assigned to an unknown local pollen donor. Using these assignments, I then determined pollen dispersal distance and degree of dispersal in A. tuberculatus and S. lycopersicum in the four experimental populations, and used these data to model pollen dispersal patterns. For both species, and across sites, pollen dispersal decreased with increasing distance to the pollen donor, but the degree of dispersal and slope differed among sites in A. tuberculatus and S. lycopersicum , respectively. The relationship between pollen dispersal and distance was best fit by the exponential decay and inverse power curves, while pollen dispersal probability histograms were best fit by exponential-tailed PDFs. These results suggest that, across four sites in the New York metropolitan area, A. tuberculatus and S. lycopersicum pollen dispersal patterns are generally exponential-shaped, but the rate of decrease (i.e. slope) and degree of dispersal may differ among sites. Further, these results suggest that pollen dispersal in cities may parallel patterns observed in less-disturbed habitats. Overall, my studies are the first to report pollen dispersal patterns in S. lycopersicum , to report pollen dispersal in roof-top habitats, and to investigate patterns among dissimilar urban sites, as well as the first to compare curve and PDF fitting in modeling pollen dispersal.
Butcher, Chelsea Lynne, "The Development and Use of Unique Molecular Markers to Study Pollen Dispersal Within Two Plant Species across Diverse Habitats in the New York Metropolitan Area" (2018). ETD Collection for Fordham University. AAI10812569.