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Full-Text Articles in Physical Sciences and Mathematics
Boundary, Costs And Trade-Offs In Reserve Design Systems, Justus Hurd
Boundary, Costs And Trade-Offs In Reserve Design Systems, Justus Hurd
Honors Theses
Due to limitations in funding and natural resources, it is infeasible to construct perfect reserve systems for large populations of critical species. For this project, our objective is to formulate a reserve design model that minimizes the distance between reserve sites meeting a threshold of biodiversity features subject to a species coverage constraints. Coupled with other spatial characteristics including reserve size and configuration, the boundary of a reserve system is of key importance. While positive area effects are gained when selecting additional sites, negative boundary length effects are also experienced. For example, it is costly to implement and maintain boundary …
Not Extinct: A Year In The Life Of The American Chesnut, Kristen Julina Stanfill
Not Extinct: A Year In The Life Of The American Chesnut, Kristen Julina Stanfill
Honors Theses
After the widespread infection of the American chestnut tree (Castanea dentata) due to the fungus Cryphonectria parasitica the species was nearly brought to extinction and now merely exists as stump sprouts. Since the fungus infects the bark of the tree but not the root systems new shoots are able to emerge and grow before once again being girdled by the fungus. Cryphonectria parasitica is believed to have been brought to America on Asian species of chestnut which possess resistance to the blight caused by the fungus. It is the plan of the American Chestnut Foundation (TACF) to integrate the genes …
The Effect Of Phosphite On Mycorrhiza Formation In American Chestnut (Castanea Dentata), Matthew T. Perkins
The Effect Of Phosphite On Mycorrhiza Formation In American Chestnut (Castanea Dentata), Matthew T. Perkins
Honors Theses
One of the primary hindrances to Castanea dentata restoration in the Southeast is the root rot disease caused by the fungus-like microorganism Phytophthora cinnamomi. Root rot can be combated by the application of mono- and di-potassium salts of phosphorous acid, which are marketed as phosphite fungicides. Despite its value in preventing infection by P. cinnamomi it is also thought that phosphite may impede root colonization by beneficial, ectomycorrhizal fungi. I hypothesized that plants given a routine application of phosphite will display fewer mycorrhizas in the root tips than those plants that were not treated with potassium phosphite. Therefore I attempted …
A Morphological Analysis Of A "Confounding" Population Of Castanea In Northwest Georgia, Jamie Dinkins
A Morphological Analysis Of A "Confounding" Population Of Castanea In Northwest Georgia, Jamie Dinkins
Honors Theses
Two species of Castanea Mill. (Fagacae) are native to North America: the tall, forest-type Castanea dentata (Marsh.) Borkh. and the smaller, shrubbier Castanea pumila (L.) Miller. There are two varieties of C. pumila: Castanea pumila var. pumila, and Castanea pumila var. ozarkensis (Johnson, 1988). In the early 1900s, chestnut blight caused by Cryphonectria parasitica (Murr.) Barr. reduced C. dentata to stumps and sprouts and severely diminished the abundance of both subspecies of C. pumila. Because Castanea species can apparently interbreed, restoration efforts have been complicated by possible hybridization between the two now shrubby species. One of these putative hybrid and …
Conversion Of Virulent Cryphonectria Parasitica From The Lula Lake Land Trust To Hypovirulent Strains, Pearl Hwang
Conversion Of Virulent Cryphonectria Parasitica From The Lula Lake Land Trust To Hypovirulent Strains, Pearl Hwang
Honors Theses
For almost a century, the fungus, Cryphonectria parasitica has existed in the United States as a wound parasite to American chestnut (Castanea dentata) trees. However, hypovirulence, evidence of spontaneous healing in Italy and Michigan, has given the American chestnut trees hope to one day be restored into its natural range. Viruses were the cause of such spontaneous healings. My hypothesis was that a viruscontaining hypovirulent strain of C. parasitica (in a brown background) would share alleles that control anastomoses with the local virulent strains, so a virus that causes hypovirulence could be transmitted into local virulent strains in vitro. Fifty …