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Articles 421 - 450 of 469

Full-Text Articles in Plant Biology

The Short-Term Effects Of Manganese Toxicity On Ribulose 1,5 Biophosphate Carboxylase In Tobacco Chloroplasts, Kerrie Elliott May 1990

The Short-Term Effects Of Manganese Toxicity On Ribulose 1,5 Biophosphate Carboxylase In Tobacco Chloroplasts, Kerrie Elliott

Masters Theses & Specialist Projects

The short-term effects of manganese toxicity on ribulose 1,5 bisphosphate carboxylase (Rubisco) activity and concentration in tobacco chloroplasts were examined. The activity of the enzyme from both manganese-treated and control plants was determined 6, 12, 18, 24 , and 48 h after introduction of manganese (80 mg/Li. Enzyme activity was determined by monitoring rates of radioactive CO2 fixation into acid stable products. A slight stimulation of the enzyme's activity was noted in experimental plants after 18 h of exposure to manganese as compared with control plants. A decrease in the enzyme's activity in experimental plants was noted after 48 …


Introduction And Enhancement Of Vegetative Cover At Lake Mead, Jennifer S. Haley, Lisa K. Croft, Suzanne E. Leavitt, Larry J. Paulson Dec 1989

Introduction And Enhancement Of Vegetative Cover At Lake Mead, Jennifer S. Haley, Lisa K. Croft, Suzanne E. Leavitt, Larry J. Paulson

Publications (WR)

Studies done by the Nevada Department of Wildlife (NDOW) and the Arizona Fish and Game between 1978 and 1981 indicate that inadequate cover may be limiting the production and survival of largemouth bass at the Lake Mead National Recreation Area (LMNRA). As a result of these studies, NDOW initiated a contract in 1986 with the Lake Mead Research Center (LMRC) to investigate means of improving habitat for game fish by introducing natural and/or artificial cover. During Phase I (1986-1987) of this contract, the shoreline of Lake Mead was surveyed for aquatic and terrestrial plant growth. Also during this time, submerged …


Temporal Patterns Of Nectar And Pollen Production In Aralia Hispida: Implications For Reproductive Success, James D. Thomas, Mary A. Mckenna, Mitchell B. Cruzan Aug 1989

Temporal Patterns Of Nectar And Pollen Production In Aralia Hispida: Implications For Reproductive Success, James D. Thomas, Mary A. Mckenna, Mitchell B. Cruzan

Biology Faculty Publications and Presentations

Large plants of Aralia hispida present their pollen and nectar in hundreds of small flowers than open sequentially over 2—3 wk in a pattern of synchronized protandry that alternates male and female phases. The primary pollinators, bumble bees, are able to discover individual plants with elevated levels of either nectar or pollen, and to return to them more often than to less rewarding plants. Both pollen and nectar are presented gradually over time in such a way as to favor traplining behavior by the bees, with many, frequent visits. In controlled environments, lifetime sugar production per flower varies among plants, …


The Effects Of Varying Light Exposure Times On The Colonization And Sporulation Of Gigaspora Margarita In The California Pepper, Mary E. Kirker Jul 1989

The Effects Of Varying Light Exposure Times On The Colonization And Sporulation Of Gigaspora Margarita In The California Pepper, Mary E. Kirker

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Arts and Sciences at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Mary E. Kirker on July 24, 1989.


Tallgrass Prairie Remnants Of Eastern Nebraska, Judith F. Boettcher, Thomas B. Bragg Jan 1989

Tallgrass Prairie Remnants Of Eastern Nebraska, Judith F. Boettcher, Thomas B. Bragg

Biology Faculty Proceedings & Presentations

Ten eastern Nebraska tallgrass prairie remnants were evaluated up to four times during the 1979 growing season to assess vegetative composition and the effects of mowing, topographic and size differences, and season of evaluation. Frequent mowing resulted in a reduced canopy cover of some species, such as big bluestem (Andropogon gerardii Vitman) (21% lower with frequent mowing), but increased cover of others, particularly the introduced species smooth brome (Bromus inermis Leyss. subsp. inermis) (35% higher cover with frequent mowing). In addition, frequent mowing resulted in a higher proportion of disturbance species. Comparing the time of mowing, canopy …


Effect Of Eastern Red Cedar On Seedling Establishment Of Prairie Plants, Dan J. Stipe, Thomas B. Bragg Jan 1989

Effect Of Eastern Red Cedar On Seedling Establishment Of Prairie Plants, Dan J. Stipe, Thomas B. Bragg

Biology Faculty Proceedings & Presentations

To test the hypothesis that eastern red cedar (Juniperus virginiana L.) is allelopathic, seedling establishment of five herbaceous prairie species was evaluated by growing seeds in soil collected beneath and adjacent to a stand of this tree species. While four species showed no significant effect, the germination of one species, finger coreopsis (Coreopsis palmata Nutt.), was significantly reduced. Since eastern red cedar is an early invader of unburned prairie, such an allelopathic effect, even on only a few species, is of particular concern in that it has the potential to hasten degradation of invaded prairie sites.


Effect Of Burning On Germination Of Tallgrass Prairie Plant Species, Sherry R. Rohn, Thomas B. Bragg Jan 1989

Effect Of Burning On Germination Of Tallgrass Prairie Plant Species, Sherry R. Rohn, Thomas B. Bragg

Biology Faculty Proceedings & Presentations

Seeds from 10 prairie plant species of burned and unburned portions of three tallgrass prairies were collected and tested for germinability. Germination of big bluestem (Andropogon gerardii Vitman) consistently averaged higher with burning. Indiangrass (Sorghastrum nutans L.) and sideoats grama [Bouteloua curtipendula (Michx.) Torr.] averaged 5% higher with burning on two of the three sites, although for indiangrass average germination for all three sites was 7% lower. Species for which germination declined with burning were false sunflower [Heliopsis helianthoides (L.) Sweet var. scabra (Dun.) Fern.], -13%; whole leaf rosinweed (Silphium integrifolium Michx.), -10%; and white …


Establishing Warm-Season Grasses And Forbs Using Herbicides And Mowing, Thomas B. Bragg, David M. Sutherland Jan 1989

Establishing Warm-Season Grasses And Forbs Using Herbicides And Mowing, Thomas B. Bragg, David M. Sutherland

Biology Faculty Proceedings & Presentations

The objective of this study was to provide a preliminary assessment of the use of selected herbicides in establishing a diverse stand of prairie grasses and forbs. An upland and a lowland site in eastern Nebraska, consisting of well-drained, fine-silty clay, loess-derived soils, were seeded with 23 native prairie grass and forb species and subsequently mowed or treated at rates of 0.6, 1.1, 1.7, and 2.2 kg/ha with atrazine [6-chloro-Nethyl- N' -(l-methylethyl)-l ,3,S-triazine-2,4-diamine] or 2,4-0 (2,4-dichlorophenoxyacetic acid). Treatments were applied at one and two-year intervals. Canopy cover in unreplicated treatment areas (12 x 30 m) was evaluated in ten randomly …


An Annotated List Of The Vascular Plants Of Keith County, Nebraska, David M. Sutherland, Steven B. Rolfsmeier Jan 1989

An Annotated List Of The Vascular Plants Of Keith County, Nebraska, David M. Sutherland, Steven B. Rolfsmeier

Biology Faculty Publications

This study provides an annotated list of the vascular plants known to exist outside of cultivation in Keith County, Nebraska. Listed are a total of 599 species, subspecies and varieties belonging to 302 genera of 87 families. Notes are included about frequency and habitat for each of the taxa. 264 (44.1 %) of the taxa listed were previously unreported for Keith County. Additionally, the paper discusses vegetation regions in the county and gives information in tabular form about numbers of the flora in different taxa, the ten largest families, numbers of taxa of different growth habits, and numbers of taxa …


New And Corrected Floristic Records For Nebraska, Steven B. Rolfsmeier, Robert B. Kaul, Marjorie M. Garabrandt, David M. Sutherland Jan 1988

New And Corrected Floristic Records For Nebraska, Steven B. Rolfsmeier, Robert B. Kaul, Marjorie M. Garabrandt, David M. Sutherland

Biology Faculty Publications

New distributional data are given for 54 species of vascular plants in Nebraska. Twenty are newly recorded for the State. 23 are shown to be more widespread than was previously known, seven are shown to have more restricted ranges than previously reported. the records of one species attributed to the State are shown to be based on misidentifications. and the presence in the State of three species collected long ago is confirmed by recent collections.


Historical Notes On Collections And Taxonomy Of Penstemon Haydenii S. Wats. (Blowout Penstemon), Nebraska's Only Endemic Plant Species, David M. Sutherland Jan 1988

Historical Notes On Collections And Taxonomy Of Penstemon Haydenii S. Wats. (Blowout Penstemon), Nebraska's Only Endemic Plant Species, David M. Sutherland

Biology Faculty Publications

Penstemon haydenii was originally described in 1891 by Sereno Watson and was named for its first collector, the geologist and explorer Ferdinand V. Hayden, who probably collected it in the late summer of 1857 in the" Sand Hills of Loup Fork," Nebraska. The Hayden specimen which Watson saw in the Gray Herbarium at Harvard University had evidently been labeled with an incorrect location. Watson did not base his description on that early specimen but upon a more complete specimen, also in the Gray Herbarium, taken by Herbert J. Webber in Thomas County in 1891; so the Webber specimen, not the …


The Isolation And Identification Of Filamentous Fungi From Distribution Systems, Ground Water, Cisterns And Hemodialysis Water, Tammy J. Liles Aug 1987

The Isolation And Identification Of Filamentous Fungi From Distribution Systems, Ground Water, Cisterns And Hemodialysis Water, Tammy J. Liles

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Arts and Sciences at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Tammy J. Liles on August 18, 1987.


New And Corrected Records Of The Flora Of Nebraska, Steven B. Rolfsmeier, Robert B. Kaul, David M. Sutherland Jan 1987

New And Corrected Records Of The Flora Of Nebraska, Steven B. Rolfsmeier, Robert B. Kaul, David M. Sutherland

Biology Faculty Publications

New distributional data are provided for 27 species of vascular plants in Nebraska, eight newly recorded as growing wild in the State. The record of one species previously attributed to the State is shown to be based upon misidentified specimens, the range of another is shown to be much more restricted in Nebraska than previously reported, and nomenclature is corrected for two species.


Nebraska Plant Distribution, David M. Sutherland, Robert B. Kaul Jan 1986

Nebraska Plant Distribution, David M. Sutherland, Robert B. Kaul

Biology Faculty Publications

Distribution notes based on recent collections and herbarium work are provided for 46 Nebraska plant taxa, including 43 flowering plants, two ferns, and one liverwort. The list includes several plants that are new to the State and provides range extensions within the State for many others. Several previously- published distribution records believed to be erroneous are also discussed.


Extrafloral Nectaries On Plants In Communities Without Ants: Hawaii, Kathleen H. Keeler Jan 1985

Extrafloral Nectaries On Plants In Communities Without Ants: Hawaii, Kathleen H. Keeler

School of Biological Sciences: Faculty Publications

Since the Hawaiian Islands lack native ants, it was hypothesized that extrafloral nectaries, an ant-related mutualistic trait, should be lacking on native species. Presence of extrafloral nectaries (EFNs) on plants was determined by direct observation and related to vegetation structure and floral composition. Frequency of plants with EFNs was low by all possible comparisons. However, several endemic species had functional EFNs. The hypotheses to explain these anomalies are (1) phylogenetic inertia or (2) mutualism with some other organism than ants.


Benthic Diatom Community Dynamics In The Colorado River: Interactive Effects Of Periodic Dessication And Current Regime, Christopher Gerard Peterson Dec 1984

Benthic Diatom Community Dynamics In The Colorado River: Interactive Effects Of Periodic Dessication And Current Regime, Christopher Gerard Peterson

Publications (WR)

The response to periodic desiccation of periphyton communities developed in eddy environments or in areas exposed to variable, direct current was examined. Algal communities were incubated on clay tiles for between 2 and 12 weeks in the Colorado River, directly below Hoover Dam from October, 1983 - January, 1984. Mean daily discharge from the dam decreased over this period. To assess the influence of these discharge changes on community dynamics, samples collected over the first 12 weeks of the investigation were compared to samples of the same age collected over the final 8 weeks.

The small diatom taxon Achnahthes spp …


Phenotypic Differences In Populations Of Euonymus Americanus L. From The Central United States & Autecological Studies Of This Species In A Deciduous Forest Of Kentucky, Paul Bayer May 1984

Phenotypic Differences In Populations Of Euonymus Americanus L. From The Central United States & Autecological Studies Of This Species In A Deciduous Forest Of Kentucky, Paul Bayer

Masters Theses & Specialist Projects

The concentrations of sodium and potassium in the leaves of Euonymus americanus collected from a relict hardwood forest during a four month period showed a possible winter conditioning pattern. Seeds collected from this same relict stand would not germinate, even though they were subjected to a wide variety of germination experiments. Phenotypic differentiation in fully developed leaves was not found; however, differences related to the length of the growing season were noted. Autecological studies of Euonymus americanus should be continued to investigate the role of this plant in relict hardwood stands.


Vegetative Key To Grasses Of The Sand Hills Region Of Nebraska, David M. Sutherland Jan 1984

Vegetative Key To Grasses Of The Sand Hills Region Of Nebraska, David M. Sutherland

Biology Faculty Publications

All illustrated key is provided that will facilitate identification of grasses in the vegetative condition in the Sand Hills region of Nebraska. The key separates 97 species, varieties, and species groups and discusses or partially separates 14 additional taxa. It emphasizes characteristics that may be observed in the field with a hand lens and is illustrated with 109 camera lucida drawings.


Radiological Monitoring Of Select Faunal Species Indigenous To Environs Of The Maxey Flats Shallow Land Burial Facility, Robert Bruce Burns Dec 1983

Radiological Monitoring Of Select Faunal Species Indigenous To Environs Of The Maxey Flats Shallow Land Burial Facility, Robert Bruce Burns

Morehead State Theses and Dissertations

A Thesis presented to the faculty of the School of Sciences and Mathematics at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Robert Bruce Burns on December 14, 1983.


The Effect Of Dwarf Mistletoe (Arceuthobium Americanum) Upon A Portion Of The Carbon Budget Of Lodgepole Pine (Pinus Contorta), Nancy Ellen Broshot Nov 1982

The Effect Of Dwarf Mistletoe (Arceuthobium Americanum) Upon A Portion Of The Carbon Budget Of Lodgepole Pine (Pinus Contorta), Nancy Ellen Broshot

Dissertations and Theses

Arceuthobium americanum is a vascular plant which is parasitic upon Pinus contorta var. murrayana. Its documented effects include reductions in host growth, vigor and wood quality. The specific physiological changes that occur in the host are, for the most part, unknown.

In an attempt to understand the manner in which the mistletoe alters its host's carbon budget, a model is proposed which states that the host plant has priorities for carbon allocation. The model proposes that the parasite will access the host's carbon initially in terms of carbon intended for storage, next, in terms of carbon intended for growth, …


Variation In Branch Growth Characteristics Of Pinus Contorta Infected With Arceuthobium Americanum, Lynn Anne Larsen Jan 1981

Variation In Branch Growth Characteristics Of Pinus Contorta Infected With Arceuthobium Americanum, Lynn Anne Larsen

Dissertations and Theses

Arceuthobium americanum is a flowering plant which parasitizes Pinus contorta (Lodgepole pine). This study examined branch performance of P. contorta infected to varying degrees with A. americanum.


Plant Response To The Barstow To Las Vegas Motorcycle Race Of November, 1974, Candace E. Horsley Aug 1979

Plant Response To The Barstow To Las Vegas Motorcycle Race Of November, 1974, Candace E. Horsley

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to determine the disturbance spectrum of the perennial plant vegetation by the Barstow to Las Vegas motorcycle race. Transects were taken at the pit area, starting line, and at various locations along the race course. Measurements were also taken in undisturbed control sites near the test areas, the topographic and bio tic features being judged as equal. Methods employed consisted of aerial photograph analysis just before and after the race. On site ground measurements were taken four years after the 1974 motorocycle event. Measurements of diversity, stability, productivity, and community quality were calculated. The …


The Effects Of Two Polychlorinated Biphenyls (Aroclor 1016r And Aroclor 1242r) On The Growth And Chlorophyll Production Of Cultures Of Selenastrum Capricornutum, Jude William Grosser May 1979

The Effects Of Two Polychlorinated Biphenyls (Aroclor 1016r And Aroclor 1242r) On The Growth And Chlorophyll Production Of Cultures Of Selenastrum Capricornutum, Jude William Grosser

Morehead State Theses and Dissertations

A thesis presented to the faculty of the School of Sciences and Mathematics at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Jude William Grosser on May 11, 1979.


Ecotypic Differentiation Of Andropogon Virginicus L. In Relation To Strip Mine Spoil Banks, Valina Kay Hurt May 1979

Ecotypic Differentiation Of Andropogon Virginicus L. In Relation To Strip Mine Spoil Banks, Valina Kay Hurt

Masters Theses & Specialist Projects

Reciprocal plantings of populations of broomsedge, taken from an abandoned strip mine and from an abandoned farm plot in south central Kentucky, on strip mine spoil and abandoned field soil resulted in patterns of populations differentiation. Clonal plantings of populations from strip mine habitats and old field development appeared equal in height and biomass when grown on old field soils in both field trials and growth chamber studies. Populations when planted in strip mine soils in field trials and controlled growth experiments. Later flowering in strip mine populations may be a key to survival strategy in the harsh microclimates of …


A Taxonomic & Physiographic Survey Of Scirpus In Kentucky With Problem Species Complex Analysis, Sally Arnold May 1979

A Taxonomic & Physiographic Survey Of Scirpus In Kentucky With Problem Species Complex Analysis, Sally Arnold

Masters Theses & Specialist Projects

The genus Scirpus was analyzed according to species occurrence and physiographic distribution in the State of Kentucky. The morphology of three taxonomic problem complexes, Scirpus atrovirens-georgianus, Scirpus validus-acutus, and Scirpus cyperinus-eriophorum-pelius-pedicellatus was evaluated to determine whether or not their components are distinct among the Kentucky specimens. Remaining taxa were likewise evaluated and identified. A key to Scirpus in Kentucky and a taxonomic treatment are presented.


Anatomical Observations On Floating Leaves, Robert B. Kaul Jan 1976

Anatomical Observations On Floating Leaves, Robert B. Kaul

School of Biological Sciences: Faculty Publications

An examination of 24 genera of aquatic plants having floating leaves and leaf-like thalli has been made. Functional stomata occur on the adaxial sides of floating leaves of angiosperms and some ferns, and in some floating leaves there are stomata on the abaxial surface as well. Most floating leaves have prominently chambered mesophyll, and in some instances the chambers are locally enlarged and form buoys.


A Preliminary Survey Of The Vascular Flora Of Upper Tygarts Creek, Carter County, Kentucky, William Michael Huffaker Jul 1975

A Preliminary Survey Of The Vascular Flora Of Upper Tygarts Creek, Carter County, Kentucky, William Michael Huffaker

Morehead State Theses and Dissertations

A thesis presented to the faculty of the School of Sciences and Mathematics at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by William Michael Huffaker on July 23, 1975.


Tree Ring-Widths In Pinus Ponderosa And Pseudotsuga Menziesii As Indicators Of Past Annual Precipitation, Gerald L. Bliss Jan 1974

Tree Ring-Widths In Pinus Ponderosa And Pseudotsuga Menziesii As Indicators Of Past Annual Precipitation, Gerald L. Bliss

All Master's Theses

This paper presents a study designed to determine how well tree ring-widths in Pinus ponderosa and Pseudotsuga menziesii indicate the past annual precipitation in the area of the Rimrock-Tieton Dam, Yakima County, Washington. The study was based on ten trees sampled from a small homogeneous site selected for apparent dryness. A Swedish increment bore was used to extract four cores from each tree. The cores were mounted, dated, measured, and standardized. Linear regression and correlations were used to analyze the data. The results revealed that Pseudotsuga menziesii ring widths are slightly better indicators of the annual precipitation than the ring-widths …


Douglas-Fir Seed Volatile Oils In Seed Detection By Deer Mice, Millard S. Deusen Jan 1974

Douglas-Fir Seed Volatile Oils In Seed Detection By Deer Mice, Millard S. Deusen

All Master's Theses

This study investigated the role of the volatile oils of Douglas-fir seeds in olfactory seed detection by deer mice. The removal of these volatile oils from the seed reduces the ability of the deer mice to detect the seeds.

A method is outlined for the removal of the volatile oils from the seeds as well as a method to purify the oils for possible identification and quantification of individual components.


A Comparison Of Two Artificial Substrates In The Determination Of Net Primary Production, Leland C. Faulconer Jan 1974

A Comparison Of Two Artificial Substrates In The Determination Of Net Primary Production, Leland C. Faulconer

All Master's Theses

This study was to determine if a significant difference exists between two types of artificial substrates used to measure the growth rate of periphyton in a warm spring. Chlorophyll was used as an indirect measure of biomass in comparing the substrates and estimating net primary production. A semi-quantitative algal survey was done for each of the sites sampled.

The study was carried out for one year and it was demonstrated that there was a statistically significant difference between the two substrates.