Date of Award

2014

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

McCord, Elzie

Keywords

Invasive Plant Species, Plant Biology, Native Florida Plants

Area of Concentration

Biology

Abstract

Ambrosia artemisiifolia (common ragweed) is a widespread native throughout North America and is invasive in Europe and Asia. Therefore, it has the potential to affect many habitats and plant communities. Its allelopathic effects were studied to help determine its environmental impacts. Previous experimental protocol showed thiarubrine A from root extracts negatively affects plant growth. Therefore, a crude root extract was applied to Schinus terebinthifolia (Brazilian pepper), Aeschynomene americana (shyleaf), Solidago stricta (wand goldenrod), Callicarpa americana (American beautyberry), and Symphyotrichum dumosum (rice button aster) seeds. A purified root extract, obtained by liquid-liquid extraction and column chromatography, was applied to Brazilian pepper and shyleaf seeds. The effects of herbicide treatments (bromacil, diuron, and hexazinone) were compared to those of the crude extract. Germination rate, seedling elongation, and seedling biomass were examined to determine treatment effects.Methanol and the purified extract caused significantly lower germination rates than water or the crude extract with shyleaf and significantly reduced Brazilian pepper and shyleaf seedling elongation compared to water. Methanol showed greater negative effects on growth than expected, while the crude extract had less of a negative effect on germination and biomass than expected. Bromacil and hexazinone were much more growth-inhibiting than the crude extract.

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