Bianca Knoll

Dissertation Summary:

I am interested in the evolution of the ability of certain plants to hyperaccumulate substances, such as heavy metals and metalloids, that are normally toxic to plants in such high doses. In particular, I study two genera in the fern family Pteridaceae that hyperaccumulate arsenic. It is my goal to place hyperaccumulation in a phylogenetic context and to analyze the evolution of this trait in these terms. To first determine taxic delineations, I plan to elucidate the phylogeny of the genus Pityrogramma, and possibly that of the genus Pteris as well. I will then perform ecophysiological studies to determine which taxa in these clades have the greatest ability to uptake arsenic from the soil. These taxa may then be used in phytoremediation efforts to efficiently and cheaply remove toxic arsenic from contaminated areas. Finally, I will attempt to answer questions about the timing and potential adaptive advantage of the evolution of the arsenic hyperaccumulation trait.