Biology Commons^™

Global Population Divergence Of A Cosmopolian Desert Plant, Victor Ryan Alfaro

Biology ETDs

Genetic and phenotypic variation can have different patterns within a species if it has populations with contrasting histories. Populations can have discrete differences that are shaped by different evolutionary scenarios, but within each population, range, or region, traits and association with fitness can also be affected by both edaphic and landscape variation. For my dissertation, I surveyed and experimentally analyzed variation and adaptive potential in Sahara mustard (Brassica tournefortii), a desert annual that has endemic, invasive, and agricultural populations in Africa, Asia, and the Americas. Although my multi-trait analysis generated complex results, my findings can be applied to …

Spatio-Temporal Dynamics Of Fungal Communities And Their Effects On Plants, Kel Cook

Biology ETDs

Fungi perform several critical functions in the environment. Spatiotemporal distributions of fungal communities will mediate when and where these functions happen and how they vary across the landscape. I first explored tropical tree canopy fungal community variation at small spatial scales and documented near total turnover of fungi across sub-meter distances and among adjacent substrates. The second chapter analyzed fungal turnover over the course of three years, where community stability was driven primarily by abundant fungi. In the third chapter, I tested effects of the environment, including host plant and habitat, on canopy fungal communities and found only small effects, …

Warming Up: Climate Change Related Shifts Of Mycorrhizal Fungal Communities In High Latitude Ecosystems, Megan Rae Devan

Biology ETDs

This dissertation examines how climate change affects mycorrhizal fungal communities in boreal and arctic ecosystems. In chapter one, I revealed that increases in fire severity and related increases in deciduous tree dominance result in greater Ascomycota relative abundance (RA) and subsequent declines in Basidiomycota RA. In chapter two I analyzed the effects of post-fire mycorrhizal fungal communites on host growth. There were trends at the fungal genus level that were largely reflected at the guild level across all hosts; however, there were some fungal genera that had the opposite effect on different host species. In chapter three, I found host …

The Fate Of Xylem-Transported Co2 In Plants, Samantha S. Stutz, David T. Hanson

Biology ETDs

The concentration of carbon dioxide in tree stems can be ~30-750 times higher than current atmospheric [CO₂]. Dissolved inorganic carbon enters the xylem from root and stem respiration and travels with water through the plant. However, the fate of much of this xylem-transported CO₂ is unknown. In these studies I examined the fate of xylem-transported CO₂ traveling through the petiole and leaf. This was accomplished by placing cut leaves from a woody and herbaceous C₃ species, and a Kranz-type C₄ species, in a solution of dissolved NaH¹³CO₃ at concentrations similar to …

A Distributional And Taxonomic Study Of Ratibida Columnifera Var. Columnifera, Ratiba Columnifera Var. Pucherrima, And Their Hybrids In New Mexico, Walter W. Marshall

Biology ETDs

The classification and distribution of Ratibida columnifera var. columnifera Woot. and Standl. and R. columnifera var. pulcherrima (DC.) Woot. and Standl. are complex. Some floras list R. columnifera var. pulcherrima as a purple colored form or variety of the species while other authors refer to this taxon as a separate species of Ratibida. The purpose of this study is to clarify the taxonomic status of the two forms by determining and differences in morphology, distribution, taxonomy, and ecology.

An attempt has been made to determine the route by which R. columnifera columnifera and R. columnifera pulcherrima were distributed. After this …

Use Of The Antibiotics, Streptomycin And Terramycin, As Growth Stimulants For Orchid Seedlings., Margaret W. O'Neill

Biology ETDs

Antibiotics first came to the public's attention in 1945, when penicillin and streptomycin were released by the United States government to fight human diseases. Later, other antibiotics were released and experimental work was done on control of plant and animal diseases. By 1948 plant pathologists found that certain plant diseases such as walnut blight, tomato and pepper bacterial spot, soft rot, cucumber, downy mildew, chrysanthemum bacterial wilt, and lilac bacterial blight could be controlled by antibiotics.

A Bioecological Study Of Pinyon Pine-Juniper Association At Juan Tabo In The Sandia Mountains Of New Mexico, Robert Hallett Parker

Biology ETDs

A survey of literature shows that no community or bioecological study has ever been made of the pinyon pine-juniper association as it occurs in the Upper Sonoran Life Zone in New Mexico and southern Colorado. This deficiency of knowledge relative to the pinyon pine-juniper community is in direct contrast to several studies that have been made of the same community in Arizona and Utah by the presence of dominant trees of entirely different species. Relative to the association in New Mexico, one of the dominant tress, the pinyon pine (Pinus edulis Engelm), has been investigated, but no bioecological and …

Developmental Anatomy Of Descurainia Pinnata, Robert D. Spensley

Biology ETDs

This study is concerned mainly with the morphological development of Descurainia pinnata subspecies ochroleuca (Wooton) Detling, a member of the tribe Sisymbrieae and subtribe Descurainiinae of the Cruciferae. Although commonly referred to as Sophia by many botanists, this genus is otherwise known as Descurainia and sometimes partly included in Sisymbrium. D. pinnata is listed as Sisymbrium canescens in Gray's manual, as Sophia pinnata by Coulter and Nelson, as Descurainia pinnata by Kearney and Peebles, and as Sophia ochroleuca by Wooton and Stanley.

The Ethnobotany Of The Acoma And Laguna Indians, George R. Swank

Biology ETDs

The Indian lives close to nature and utilizes the plants which grow about him, and these uses differ among various tribes. In order therefore to understand the ethnobotany of any group of Indians it is necessary to know something of their history, customs, mythology, religion and medicine. Hence in treating the ethnobotany of the Acoma and Laguna Indians the above phases of their culture will be discussed as they relate to these two pueblos.