Biology Commons^™

Composition And Change Of Maritime Hammock Flora In East-Central Florida After 20 Years, Donald John Spence

Retrospective Theses and Dissertations

The vegetation of eight east-central Florida maritime hammocks studied in 1997 were compared to similar data collected over 20 years ago. Study sites are located in the northern half of the Indian River Lagoon system mostly within Canaveral National Seashore and Merritt Island National Wildlife Refuge. The upland hammock vegetation throughout the state generally has an oak-palm association, but here these species dominate. Results show that sabal palm, live oak, laurel oak, and pignut hickory, the four dominant tree species in 1976-77, are still dominant in 1997; however, there has been a loss in tree species richness. Most shrub species …

Intraspecific And Diffuse Competition: The Response Of Nassella Pulchra In A California Grassland, Andrew R. Dyer, Kevin J. Rice

Faculty Publications

In inland California grasslands, the high densities of alien annual species have altered the growing environment for native perennial grasses. Using variable-density plots, we measured the influence of intraspecific competition (conspecifics only) and diffuse competition (mixed-composition neighborhoods that include conspecifics) on growth and survival of Nassella pulchra, purple needlegrass. We assessed the effects of intraspecific and diffuse competition in weeded plots and unweeded plots, respectively, across a density gradient of N. pulchra plants (16–356 plants/m2). We used summer fire and spring sheep grazing to reduce diffuse competition in unweeded plots. The potential effect of rooting volume on competitive interactions …

Selection Of Populations Of Puccinia Recondita F. Sp. Tritici For Shortened Latent Period On A Partially Resistant Wheat Cultivar, Jeffery S. Lehman, Gregory Shaner

Biology and Earth Science Faculty Scholarship

Wild-type fungal population 851-WT was selected for shortened latent period on cv. CI 13227 for five uredinial generations to study the adaptation of Puccinia recondita f. sp. tritici to partially resistant wheat cultivars. Differences among wild-type and selected populations for traits contributing to parasitic fitness (i.e., latent period, infection frequency, and uredinium area and growth rate) were assessed in monocyclic infection experiments on susceptible cv. Monon and partially resistant cvs. Suwon 85, Sw 72469-6, L-574-1, and CI 13227. Differences were greatest among fungal populations on cv. CI 13227. The mean latent period of selected population 851-C5 was 2 days shorter …

Phenology Of Apothecium Production In Populations Of Monilinia Vaccinii-Corymbosi From Early- And Late-Maturing Blueberry Cultivars, Jeffery S. Lehman, Peter V. Oudemans

Biology and Earth Science Faculty Scholarship

Pseudosclerotia were evaluated for differences in timing of apothecium development in four controlled experiments conducted over a 2-year period. In a separate experiment, conidia from 10 randomly selected isolates from both of the fungal populations were used to inoculate open flowers. Germination of pseudosclerotia produced from these artificial inoculations also was evaluated. The timing and rate of shoot elongation for cvs. Weymouth and Jersey were assessed in one greenhouse and two field experiments. Average development times for the fungal population from cv. Weymouth were 8 to 15 days earlier or 33 to 42% less than those for the population from …

Selective Predation On The Seeds Of Woody Plants, Scott J. Meiners, Edmund W. Stiles

Faculty Research & Creative Activity

Selective predation on the seeds of woody plants. J. Torrey Bot. Soc. 124: 67-70). 1997.-Seed predation may be an important factor influencing the structure of successional plant communities. We used a cafeteria-style experiment, placed in an old field and an early successional forest, to determine predator preferences for seeds of nine species of woody plants. Intensity of seed predation was equivalent in both sites. Seed predators preferred Acer saccharum, flex vertic illata, and Viburnum dentatum, but this was not related to seed mass. Predation intensity was more variable in the old field than in the forest, possibly related to the …

Conidial Germination And Infection By Diplocarpon Rosae On Susceptible And Resistant Rose Species, Robert J. Wiggers, J. G. West, Josephine Taylor

Faculty Publications

Conidial germination and infection by Dipplocarpon rosae, the causal organism of rose blackspot, were examined on two resistant species of roses, Rosa roxburghii and R. wichuraiana and two susceptible hybrid tea roses (R. hybrid cv. Chicago Peace and Garden Party). Fungal conidia germinated and gave rise to subcuticular mycelium that formed haustoria within epidermal cells of all four roses tested. On the resistant rose species, epidermal cells associated with the infection site became necrotic, indicating that a hypersensitive response is involved in conferring their resistance D. rosae.

Selective Predation On The Seeds Of Woody Plants, Scott Meiners, Edmund Stiles

Faculty Research & Creative Activity

Selective predation on the seeds of woody plants. J. Torrey Bot. Soc. 124: 67-70). 1997.-Seed predation may be an important factor influencing the structure of successional plant communities. We used a cafeteria-style experiment, placed in an old field and an early successional forest, to determine predator preferences for seeds of nine species of woody plants. Intensity of seed predation was equivalent in both sites. Seed predators preferred Acer saccharum, flex vertic illata, and Viburnum dentatum, but this was not related to seed mass. Predation intensity was more variable in the old field than in the forest, possibly related to the …

An Analysis Of The Variation Within Cratoxylum Arborescens (Clusiaceae) In Malesia, A.C. Church, P.F. Stevens

Biology Department Faculty Works

The variation within the widespread West Malesian species Cratoxylum arborescens (Vahl) Blume was analyzed and three distinctive variants were found. These are recognized formally as varieties, var. arborescens, var. miquelii King, and var. borneense A.C. Church & P.F. Stevens. A key and full descriptions are given. The characters employed to delimit the three taxa are discussed and the selection of varietal rank is justified.

A Comparative Study Of The Benthic Population In Weir Ponds Draining Watersheds Of The Fernow Experimental Forest, Parsons, West Virginia, Kevin Dwayne Brittingham

Theses, Dissertations and Capstones

A study of the benthos of weir ponds draining watersheds of the Fernow Experimental Forest (FEF) was conducted in 1994-1995. The objectives of this study were: (1) to relate differences in weir pond faunas to watershed treatments on the FEF, and (2) to compare current weir pond faunas to those described in 1973 by Steve Harris. In 1971-1972, there were fewer invertebrates but greater taxa richness than in 1994-1995. Total density varied among weir pond and between studies with numbers in the 1971- 1972 study ranging from 26,168 to 79,259 individuals collected, while numbers in the 1994-1995 study raged from …

Macrophyte-Macroinvertebrate Interactions In A Lentic Ecosystem And The Effect Of Fluridone Treatment To Control Myriophyllum Spicatum L., Gregory J. Moeller

Dissertations and Theses @ UNI

Myriophyllum spicatum L. is an exotic macrophyte that can become pestiferous in lentic ecosystems. Two field studies were conducted to investigate: 1) epiphytic macroinvertebrates associated with M. spicatum and native macrophytes; and 2) epiphytic macroinvertebrate community response to fluridone treatment for M. spicatum control.

In the first study evaluating epiphytic macroinvertebrates associated with M. spicatum and native macrophytes, triplicate samples were collected at three sites in both Auburn and Zumbra Lakes, Minnesota, USA. One site in each lake contained primarily M. spicatum, the second site contained M. spicatum and native vegetation, and the third site was dominated by native …

Evaluation Of The Success Of Constructed Wetlands In The Cave Run Lake Watershed, April Diane Haight

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by April Diane Haight on December 10, 1996.

Twig, Branch, And Stem Diseases Of Pine, John R. Hartman

Agriculture and Natural Resources Publications

Tip Blight

Tip blight, caused by the fungus Sphaeropsis sapinea (formerly Diplodia pinea), is a serious disease of mature Austrian, Scots (Scotch), and Mugo pines in Kentucky. In the landscape, tip blight is normally not observed until pines reach about 12 years old and begin to bear cones. Severe infections year after year can greatly weaken and eventually kill affected pines.

Isolation From Soil Microorganisms That Are Inhibitory To Wheat Seeding Pathogens, Kynita Wilson-Humphrey

McCabe Thesis Collection

Many diseases caused by bacteria, viruses, or fungi are responsible for the ruin of a great number of crops annually. At present, many of these crops are being treated for diseases by synthetic or man-made chemicals. Some of the chemicals have been proved to have adverse effects on the environment, including humans and animals. Very few non-chemical means are available to farmers at this time to control these pathogens. This is due to the fact that many of the means of control have little effect against the pathogens or diseases. This research attempts to isolate microorganisms from the soil which …

Floristics, Plant Community Structure And Bank Profiles, For Five Sites Along The Middle Ohio River, Amy Nicole Morris

Theses, Dissertations and Capstones

Plant community structure, floristics, and bank profiles for five sites along the middle Ohio River were described. Values obtained were compared with a similar study by Clagg and Mills in 1978 on four of the five sites. A total of 186 plant species was observed in the plant community and floristic study. Glenwood Bend had the greatest diversity with 109 plant species. Mason-Pomeroy had the lowest diversity with only 35 plant species. Six species, representing 3.2 percent of the total observed number of species, were present at all five sites. The majority of species, 51 percent, were present at only …

Infection And Fungal Development Of Tubakia Dryina On Sweet Gum (Liquidambar Styraciflua), Josephine Taylor, Shane Clark

Faculty Publications

Infection and fungal development of Tubakia dryina were investigated on leaves of sweet gum using a combination of microscopic techniques. Conidia of T. dryina adhered to the leaf surface and formed septate germ tubes. Germ tubes terminated in small appressoria that formed directly over epidermal cells. Intra- and intercellular hyphae ramified extensively throughout the leaf tissue. Host cells associated with the infection site became necrotic and collapsed, resulting in macroscopic disease symptoms.

A Second Nitrogenase In Vegetative Cells Of A Heterocyst-Forming Cyanobacterium, T Thiel, E Lyons, J Erker, A Ernst

Biology Department Faculty Works

In many filamentous cyanobacteria nitrogen fixation occurs in differentiated cells called heterocysts. Filamentous strains that do not form heterocysts may fix nitrogen in vegetative cells, primarily under anaerobic conditions. We describe here two functional Mo-dependent nitrogenases in a single organism, the cyanobacterium Anabaena variabilis. Using a lacZ reporter with a fluorescent beta-galactoside substrate for in situ localization of gene expression, we have shown that the two clusters of nif genes are expressed independently. One nitrogenase functions only in heterocysts under either aerobic or anaerobic growth conditions, whereas the second nitrogenase functions only under anaerobic conditions in vegetative cells and heterocysts. …

Effects Of Non-Point Nutrient Loading On Planktonic Community Structure And Function In A Great Lakes Coastal Wetland, Brian M. Binion

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Brian M. Binion on July 26, 1995.

The Feasibility Of Trophic Manipulation In Grayson Lake, Kentucky, U.S.A., Russell Walker Crawford

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Masters of Science by Russell Walker Crawford on July 19, 1995.

Reproductive Structure And Organogenesis In A Cottonwood, Populus Deltoides (Salicaceae), Robert B. Kaul

School of Biological Sciences: Faculty Publications

The organogenesis of inflorescences, flowers, and fruits was followed for two years in a male and a female tree of eastern cottonwood, Populus deltoides. Soon after anthesis, an inflorescence for the next year is initiated as a continuation of the apical meristem in most axillary buds of the extension shoot of the current year. Bract and then floral primordia arise helically, and by the end of summer all floral appendages are evident. Individual perianth parts are evident early in ontogeny but not at anthesis; they are vascularized independently by distal traces of discrete vascular strands that also serve the …

The Rare, Serpentine Endemic Streptanthus Morrisonii (Brassicaceae) Species Complex, Revisited Using Isozyme Analysis, Rebecca W. Dolan

Scholarship and Professional Work - LAS

The Streptanthus morrisonii (Brassicaceae) complex is a group of six narrowly-distributed obligate serpentine endemic taxa whose habitat is threatened by geothermal development. Isozyme analysis of this little-studied complex supports the delineation of two species, S. morrisonii and S. brachiatus, but is at odds with the treatment of two subspecies based on morphology. These results may be influenced by small sample sizes but genetic studies of other Streptanthus taxa have shown patterns of relatedness that often transgress subspecies boundaries based on morphology. The present study further shows that members of the S. morrisonii complex share high genetic identity values (mean …

The Vascular Flora, Rare Species And Plant Migrations Of New River Gorge National River, West Virginia, Dale William Suiter

Theses, Dissertations and Capstones

In 1978, the United States Congress designated 83.5 km/53 mi. of the New River in southern West Virginia as New River Gorge National River. The vascular flora of selected sites in NRGNR was surveyed from September 1992 through October 1994. A total of 904 taxa of vascular plants was recorded, 79.2% of which are native to West Virginia. Currently, 1337 vascular plant taxa have been documented from the New River Gorge as a result of this work as well as the work of Grafton and McGraw and Phillips. A comparison of species with the West Virginia Natural Heritage Program's rare …

Predicting Evolutionary Consequences Of Greater Reproductive Effort In Tripsacum Dactyloides, A Perennial Grass, Laura L. Jackson, Chester L. Dewald

Faculty Work

To test the prediction that a mutation causing greater reproductive effort will result in reduced vegetative vigor, we compared the seed production, growth, and carbohydrate status of normal and pistillate genotypes of the grass Tripsacum dactyloides differing in seed production by up to fourfold. We evaluated the costs of reproduction by two methods: experimental manipulation of reproductive effort and comparison of high and low-yielding genotypes. Despite the large difference in seed production, normal and pistillate (high-yielding) genotypes did not differ in growth rate over a 1-yr period. Contrary to predictions, carbohydrate reserves in the high-yielding genotype were significantly higher at …

The Soil Seed Pool Of Huffman Prairie, A Degraded Ohio Prairie, And Its Potential In Restoration, Scott Meiners, David Gorchov

Faculty Research & Creative Activity

The germinable seeds in the soil of a relict Ohio prairie were investigated to determine the composition and density of dicots of potential value in restoration. Soil samples were collected from three areas of the prairie with distinctive species compositions: swale, north upland, and south upland. Seed density and species composition were based on seedling emergence over 90 days. North upland and south upland samples yielded similar total seedling densities (5,902 and 5,109 m·2 ) while that of the swale was greater ( 15,262 m·2 ). Thirteen introduced and 18 native dicot species were present; seven of the latter were …

The Soil Seed Pool Of Huffman Prairie, A Degraded Ohio Prairie, And Its Potential In Restoration, Scott J. Meiners, David L. Gorchov

Faculty Research & Creative Activity

The germinable seeds in the soil of a relict Ohio prairie were investigated to determine the composition and density of dicots of potential value in restoration. Soil samples were collected from three areas of the prairie with distinctive species compositions: swale, north upland, and south upland. Seed density and species composition were based on seedling emergence over 90 days. North upland and south upland samples yielded similar total seedling densities (5,902 and 5,109 m·2 ) while that of the swale was greater ( 15,262 m·2 ). Thirteen introduced and 18 native dicot species were present; seven of the latter were …

Woody Vegetation Of A Disjunct Bur Oak (Quercus Macrocarpa) Forest In East-Central Nebraska, Debra Ann Beightol, Thomas B. Bragg

Biology Faculty Publications

Woody plant composition was assessed for three tree-size classes in two ravines of Oak Glen Wildlife Management Area, a disjunct oak forest in Seward County, Nebraska, using Importance Values (IV) obtained by the Point-Quarter method. Bur oak (Quercus macrocarpa Michx.) dominated the large-size class (>30 cm dbh) (IV = 258) but elms (Ulmus americana L. and U. rubra Muhl.) (IV = 130) dominated the forest in one ravine in the medium-size class (10-30cm dbh) and elm and hackberry (Celtis occidentalis L.) (IV = 114 and 27 respectively) dominated the small-size class (

Review Of American Wildflower Florilegium By Jean Andrews, David M. Sutherland

Biology Faculty Publications

This book is a collection of 50 watercolor paintings of American wildflowers ("florilegium" means, literally, "a gathering of flowers"). Accompanying each full-page painting is a summary of general information about the plant, including notes about its botanical classification, the etymology of its name, life history, distribution, description, flowering period, pollination, and propagation.

Floristic Diversity In Ten Tallgrass Prairie Remnants Of Eastern Nebraska, Judith F. Boettcher, Thomas B. Bragg, David M. Sutherland

Biology Faculty Publications

Ten eastern Nebraska tallgrass prairie remnants, varying in size from one to 18 ha, were studied or visited during the growing seasons from 1979 to 1993. A total of217 prairie plant species were recorded. Big bluestem (Andropogon gerardii), little bluestem (Andropogon scoparius), smooth brome (Bromus inermis subsp. inermis), New Jersey tea (Ceanothus herbaceus var. pubescens), false sunflower (Heliopsis helianthoides var. scabra), Kentucky bluegrass (Poa pratensis), and porcupine-grass (Stipa spartea) were prevalent in all the prairies although the specific floristic composition has been reported to vary depending on past management, topography, season of evaluation, and prairie size. Of the total species …

Meristic And Organogenetic Variation In Ruppia Occidentalis And R. Maritima, Robert B. Kaul

School of Biological Sciences: Faculty Publications

Floral meristic and organogenetic variation was sampled in Ruppia occidentalis from an alkaline lake of the Nebraska Sandhills and in Ruppia maritima var. rostrata from a saline, non-Sandhills lake nearby. The androecium is meristically stable, always having two stamens, but the gynoecium is not. Seventy-two percent of the flowers of R. maritima had four carpels and the others had three, and in 80% of inflorescences the two flowers had the same number. In about one-third of inflorescences having dissimilar carpel numbers, the four-carpellate flower was uppermost. The number of carpels in each flower of R. occidentalis ranged from four to …

Molecular Approaches For Control Of Tomato Bushy Stunt Virus, H. B. Scholthof, M. Borja, Thomas Jack Morris, A. O. Jackson

School of Biological Sciences: Faculty Publications

I N this overview strategies are discussed that are currently being tested in our laboratory in an effort to engineer resistance against tomato bushy stunt virus (TBSV) in plants. TBSV is chosen as a model-system since this is an economically important RNA virus that is well characterized at the molecular level and the virus has some interesting and potentially useful features that can be exploited to produce resistant plants. Moreover, we anticipate that the information derived from our studies with TBSV will be applicable in developing resistance to other plant viruses. Some approaches that we are attempting to apply to …

Status Of Platanthera Praeclara Sheviak & Bowles (Western Prairie Fringed Orchid) In The Platte River Valley In Nebraska From Hamilton To Garden Counties, Tanya E. Bray, Barbara L. Wilson

Biology Faculty Publications

During June and July, 1991, a search for western prairie fringed orchid was conducted in the Platte River Valley in central and west-central Nebraska. No orchids were found in the 370 sites surveyed. Factors which may contribute to the scarcity of this orchid in the area surveyed include drought conditions in the previous three years; habitat alteration by draining, ditching, herbicide application, mowing for hay, crop cultivation and planting of non-native species for hay fields; invasion of the area by trees; and the presence of alkaline soils in some areas