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Library Hours for Thursday, December 14th

All of the hours for today can be found below. We look forward to seeing you in the library.
HOURS TODAY
7:00 am - 2:00 am
MAIN LIBRARY

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WITHIN BAILEY/HOWE

Maps9:00 am - 5:00 pm

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Reference Desk9:00 am - 6:00 pm

Cyber Cafe (All Night Study)12:00 am - 8:00 am

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Special Collections10:00 am - 6:00 pm

Dana Medical Library7:30 am - 11:00 pm

Classroom Technology Services8:00 am - 4:30 pm

 

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UVM Theses and Dissertations

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Author:
Patel, Nikisha
Dept./Program:
DEPARTMENT HERE
Year:
2018
Degree:
PhD
Abstract:
Apomixis is an evolutionarily important phenomenon across plant lineages. The interaction of apomixis with hybridization and polyploidy can lead to complex patterns of reticulation, complicating efforts to reconstruct evolutionary history in groups where apomixis is common. Ferns, in particular, are rich in apomictic species, notably in centers of species diversity like East Asia. Eastern North America too is home to a number of apomictic species. We investigated the East Asian ferns in Polystichum sections Xiphopolystichum and Duropolystichum (Dryopteridaceae) in order to elucidate the evolutionary and biogeraphic history of seven apomictic species in the group: Polystichum tsus-simense, P. xiphophyllum, P. sinotsus-simense, P. pseudoxiphophyllum, P. mayebarae. P. rigens, and P. neolobatum. In addition, we examined the evolutionary origin of an undescribed apomictic cytotype of North American genus Phegopteris (Thelypteridaceae). The datasets comprised phylogenetic inference based on three nuclear and three plastid markers, analysis of mixed nucleotide signals from chromatograms generated from Sanger sequencing of nuclear markers, ploidy estimates based on flow cytometry data and spore length measurements, morphometric analysis of representative specimens collected in southwest China and nearby regions, and climatic niche models. By interpreting these multiple lines of evidence synthetically, we have discerned multiple highly reticulate complexes of polyploid lineages derived largely from diploid sexual progenitors. Our findings highlight the importance of understanding the role of apomictic reproduction in the context of species diversity, an understanding central to similar future inquiry into the diversity of East Asian and North American ferns.