Ecology and Evolutionary Biology Commons^™

Competition And Herbivory Influence The Survival, Growth, And Physiology Of Native Tree Seedlings In The Kentucky Inner Bluegrass Savanna-Woodland, James D. Shaffer

Theses and Dissertations--Biology

Terrestrial plant communities are shaped by competition for resources, herbivory, and abiotic processes. Savanna systems represent a dynamic coexistence of contrasting life forms (grasses and trees) shaped by competition and disturbance. The Kentucky Inner Bluegrass Savanna-Woodland (KIBSW) is described as an open woodland of shade intolerant species; however, climatic, and edaphic conditions can support closed-canopy forest. After European pioneer settlement (c1750-1800), over 99% of “savanna-woodlands” have been lost. KIBSW remnants are experiencing a recruitment failure, leading to a dominance shift in tree communities. I researched how tree-grass competition and mammalian herbivory influence KIBSW regeneration and maintenance. The KIBSW does not …

The Role Of Ferric Reduction Oxidases In Plant Anti-Herbivore Defense., Virginia C. Nunamaker

College of Arts & Sciences Senior Honors Theses

Iron is an essential element required for plants to carry out metabolic functions such as photosynthesis, heme biosynthesis, and chlorophyll biosynthesis. Within Arabidopsis thaliana, eight ferric reduction oxidase (FRO) genes function in iron uptake and homeostasis with tissue specific expression. However, little else is known regarding the biological role of FROs. Recent studies identify the FRO gene family as particularly responsive to the green leaf plant derived volatile (GLV) cis-3-hexenyl acetate (z3HAC). Since z3HAC acts as a wound signal and cues unaffected parts of the plant to prime defenses prior to herbivory, an increase in FRO activity in response …

Investigations Into Host-Specific Interactions And Local Adaptation In The Mycorrhizal Symbiosis, Jonathan Gonzalez

Graduate College Dissertations and Theses

Mycorrhizal fungi are soil-borne organisms that form symbiotic associations with the majority of land plants. These fungi gather and exchange mineral nutrients with plants for photosynthetically derived carbohydrates. Mycorrhizal fungi can also confer other benefits onto plants, e.g. defense against pathogens, improved water relations, tolerance to heavy metal toxicity and herbivory. The influence of mycorrhizal fungi on plant mineral nutrition and response to stress suggests that these organisms may have a role to play sustainable agriculture as well as in bioremediation and ecosystem restoration.

In contributing to this important research, I investigated host-specific interactions between mycorrhizal fungi and the sex …