Date of Graduation

Fall 2009

Degree

Master of Science in Biology

Department

Biology

Committee Chair

L. Michelle Bowe

Abstract

The rust species Puccinia mariae-wilsoni is known to infect the native wildflower, spring beauty (Claytonia virginica), but little is known about the dispersal mechanisms. Wind or ants and other insects may be responsible for dispersal by transferring fungal spermatia or spores among neighboring plants. I experimentally tested four possible vectors of spore transfer by excluding wind, ants specifically, insects in general, and residual fungal spores in the soil. Higher concentrations of flavonoids in individual spring beauties are thought to be correlated with a greater rate of infection, but the relationship has not been explored widely. Using a flower color-flavonoid relationship established by Frey (2004) in conjunction with the four treatments, the questions of whether higher flavonoid concentration within Claytonia virginica increased or decreased infection by Puccinia mariae-wilsoni, and what vectors are needed to spread the spores were addressed. Exclosure treatments in 2008 yielded significant differences between the ant-pollinator exclusion (APE) treatment and the pollinator exclusion (PE) and soil spore exclusion(SSE) treatments. In 2009, treatments again showed differences between the APE treatment and the PE and SSE treatments, and differences between the PE treatment and control and between the wind-pollinator (WPE) exclusion treatment and the PE and SSE treatments. There was an overall increase in the mean infection percentage from 2008 to 2009. In 2009, an association between flower color and infection was found: Claytonia virginica with higher flavonoids, as indicated by lighter flowers, had a lower infection rate than C. virginica with lower flavonoids as indicated by darker pink flowers.

Keywords

Puccinia mariae-wilsoni, Claytonia virginica, flavonoid, ant, rust, spring beauty, pigmentation

Subject Categories

Biology

Copyright

© Nicholas Mark Murphy

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