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Root Biomass And Production In Four Communities Within The Great Dismal Swamp, Susan West Powell Oct 1990

Root Biomass And Production In Four Communities Within The Great Dismal Swamp, Susan West Powell

Biological Sciences Theses & Dissertations

A biomass difference approach was used to measure biomass and production over eleven months in four different communities within the Great Dismal Swamp. On all sites, fine roots were the moat dynamic root component. Both biomass and production were highest on the mixed hardwood site, the least flooded site, and second highest on the cedar site, the site with the longest duration of saturation. The maple-gum and cypress sites had lower amounts of biomass and rates of production. Environmental parameters that influenced production included frequency and duration of flooding, density of the stand, and soil type.

A second method, an …


An Autecological Study Of Pyxidanthera Barbulata In The Blackwater Ecologic Preserve Virginia, John Marc Lowenthal Jul 1990

An Autecological Study Of Pyxidanthera Barbulata In The Blackwater Ecologic Preserve Virginia, John Marc Lowenthal

Biological Sciences Theses & Dissertations

Pyxidanthera barbulata (pyxie moss), a rare and endangered subshrub, has been found in decreasing numbers in it's "pine barren" habitat. An autecological study encompassing vegetation association analysis and environmental measurements was performed in the Blackwater Ecologic Preserve, its only known location in Virginia. The preserve is being subjected to controlled burning and the effect of burning on the species was evaluated. A multivariate analysis of variance was performed to identify species associations, and simple analysis of variance was done to find trends in the environmental data. Four taxa were positively associated with P. barbulata, Gaultheria procumbens, Vaccinium tenellum, Cladonia spp., …


The Relationship Between Leaf Area Index And Photosynthetic Temperature Response In Wheat (Triticum Aestivum L.) Canopies, David B. Meek May 1990

The Relationship Between Leaf Area Index And Photosynthetic Temperature Response In Wheat (Triticum Aestivum L.) Canopies, David B. Meek

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The objective of this study was to determine the effect of increasing leaf area index on the photosynthetic temperature response of a wheat canopy. Hard red spring wheat (Triticum aestivum L. cv. Veery-10) was grown hydroponically in a growth chamber, which also served as the gas-exchange chamber. Gas-exchange parameters were measured on single leaves and on wheat canopies at various leaf area indices. The temperature response curves of the canopy shifted from being steeper with a high temperature optimum to being flatter with a lower temperature optimum as leaf area index increased from 0 to 20.0 m2m …


Effects Of Chiselling And Sulfur Fertilization On Infiltration, Soil Water Content, Peak Season Biomass Production, And Botanical Composition In The Ait Rbaa Perimeter, Mohammed Tigma May 1990

Effects Of Chiselling And Sulfur Fertilization On Infiltration, Soil Water Content, Peak Season Biomass Production, And Botanical Composition In The Ait Rbaa Perimeter, Mohammed Tigma

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study evaluated the effectiveness of chiselling and elemental sulfur fertilization in improving an upland and a swale range site with fine loamy, carbonatic, typic calcixeroll soils in the Ait Rbaa Perimeter of central Morocco. Ponding infiltration, soil water content on a mass basis of the 0- to 10-cm and 10- to 20-cm soil layers, peak season biomass production, and botanical composition were monitored during the two growing seasons following the treatments (1984/85 and 1985/86). Chiselling significantly improved infiltration on both sites, although the improvement was greater on the finer and less stony swale site, where chiselling resulted in more …


Forest Canopies: Form And Functional Relationships, Steven B. Jack May 1990

Forest Canopies: Form And Functional Relationships, Steven B. Jack

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Forest canopy structure is strongly influenced by stand density due to changing competitive interactions among the individual trees and in turn directly influences stemwood volume production. The structure and dynamics of forest canopies, particularly in relation to the production of stemwood, were examined in unmanaged, even-aged stands of two dissimilar tree species, Pinus contorta var. latifolia Engelm. and Abies lasiocarpa (Hook.) Nutt. The analysis of structure-production relationships was guided by a conceptual model which generated hypotheses and led to examination of assumptions incorporated in the model.

Mean crown dimensions were related to stand density through a negative exponential function for …


The Basis Of Browsing Tolerance In Shrubs Of The Intermountain West: Growth Rates And Meristematic Potential, Jackson L. Wandera May 1990

The Basis Of Browsing Tolerance In Shrubs Of The Intermountain West: Growth Rates And Meristematic Potential, Jackson L. Wandera

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Relative growth rates (RGRs) and meristematic potential of big sagebrush (Artemisia tridentata, in some experiments ssp. tridentata Nutt. and in other experiments ssp. vaseyana [Rydb] Beetls), bitterbrush (Purshia tridentata [Pursh] DC), serviceberry (Amelanchier alnifolia Nutt.), birchleaf mountain mahogany (Cercocarpus montanus Raf.), curlleaf mountain mahogany (C. ledifolius Nutt.) and big tooth maple (Acer grandidentatum Nutt.) were quantified under both glasshouse and field conditions. The relationships between the RGRs, meristematic potential and regrowth capacity of the shrub species were then determined. Sagebrush exhibited a significantly higher RGR than the other species at both high and low …


Burning, Flaming And Herbicides For Control Of Jointed Goatgrass (Aegilops Cylindrica Host.), Blake D. Willis May 1990

Burning, Flaming And Herbicides For Control Of Jointed Goatgrass (Aegilops Cylindrica Host.), Blake D. Willis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Winter wheat stubble and dried plant residue in Conservation Reserve Program (CRP) fields were burned in the fall and spring to evaluate effects on jointed goatgrass (Aegilops cylindrica Host.) seed survival and germination. Laboratory studies were also conducted to determine minimum temperatures and heat duration needed to reduce jointed goatgrass seed viability. Maximum air temperatures attained during various field burns reached from 74 C to over 700 C. Temperatures 2.5 cm above the soil surface remained above 400 C for over 10 seconds and above 600 C for 2 to 8 seconds in burning CRP stubble. Results for the …


Morphological Responses Of Wheat (Triticum Aestivum L.) To Changes In Phytochrome Photoequilibria, Blue Light And Photoperiod, Charles Barnes May 1990

Morphological Responses Of Wheat (Triticum Aestivum L.) To Changes In Phytochrome Photoequilibria, Blue Light And Photoperiod, Charles Barnes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wheat (Triticum aestivum, L.) plants were exposed to three different levels of phytochrome photoequilibria (φ), two different photoperiods, end-of-day far-red radiation, two different levels of blue (400-500 nm) light, three levels of photosynthetic photon flux (PPF), and two types of high intensity discharge lamp types. Tillering was reduced by lowered φ, by reduced amounts on blue light and by end-of-day far-red. Main culm development was increased by lowered φ, by increased PPF, and was reduced by shortened photoperiod and by reduced blue light. Leaf length was increased by increased PPF, lowered φ, and reduced blue light but was …


A Descriptive Study Of Range Livestock Operations In The Somali Central Rangelands, Abdinasir M. Abdulle May 1990

A Descriptive Study Of Range Livestock Operations In The Somali Central Rangelands, Abdinasir M. Abdulle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Information on livestock operations, particularly what kind of livestock operations are practiced in the Somali central rangelands, and how these operations differ for different herders in different vegetation types and farming systems, could serve as a major tool in making management decisions. This study provides a detailed description of range livestock operations in the Somali Central Rangelands. It also answers some important management questions.

Range livestock operations were inventoried through personal interviews with the owners and herders. Data are supplemented by previous nation-wide and regional survey statistics. Herd productivity data which include herd structures, age, age-related sales, slaughters, gifts, and …


Autecological Characteristics Of Chrysopogon Aucheri And Cymbopogon Jwarancusa, Dominant Rangeland Grasses In Baluchistan, Mohammad Saleem May 1990

Autecological Characteristics Of Chrysopogon Aucheri And Cymbopogon Jwarancusa, Dominant Rangeland Grasses In Baluchistan, Mohammad Saleem

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Controlled environment experiments were designed to study the germination, seedling development, and defoliation responses of Chrysopogon aucheri and Cymbopogon jwarancusa to better understand their autecology and potential use in range improvement programs in Baluchistan.

In experiment 1, Cymbopogon jwarancusa had greater seed fill and viability than Chrysopogon aucheri. When incubated at six different alternating temperature regimes, seeds of Cymbopogon jwarancusa had greater cumulative germination at five temperature regimes and faster germination at the colder temperature regimes than Chrysopogon aucheri.

In experiment 2, seedling shoot and root development was characterized at 15-day intervals over a 60-day period. Seedlings of …


Carbon Dioxide Toxicity In Wheat, Robert Spanarkel May 1990

Carbon Dioxide Toxicity In Wheat, Robert Spanarkel

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research was conducted to quantify short- and long-term effects of atmospheric carbon dioxide on wheat. Growth, development, and yield of the spring wheat cultivar Veery-10 were measured in response to CO2 concentrations of 340 (ambient), 1200, and 2500 μmol moI-1 of CO2 air. These 3 CO2 levels were chosen to provide a control group, a predicted optimal CO2 environment, and a potentially toxic CO2environment, respectively. A recirculating hydroponic system provided a near-optimal root-zone environment that was identical for all CO2 treatment levels. Environmental factors, other than CO2, were …


A Study Of Striga Chromosome Numbers With A Comparison To Those Of Some Genera In The Rhinathoideae And The Orobanchaceae, Cynthia White Apr 1990

A Study Of Striga Chromosome Numbers With A Comparison To Those Of Some Genera In The Rhinathoideae And The Orobanchaceae, Cynthia White

Biological Sciences Theses & Dissertations

New chromosome counts are given for nine species of Striga including S. elegans (n=18), S. asiatica (n=19), S. forbesii (n=22), S. densiflora (n=26), S. aspera (n=27), S. passargei (n=28), and S. hermonthica (n=30). Previous counts reported for S. gesnerioides (n=20) and S. angustifolia (n=20) are verified. Evidence from the base number (x=10), chromosome counts, and differences in chromosome size (bimodality) suggests that the genus is an allotriploid with a descending aneuploid series. Genomic change appears to occur by different mechanisms in the Rhinanthoideae; some genera display a euploid series, others show aneuploidy, and some are very stable. Genera examined …


The Effect Of Plant Growth Regulators On The Growth Of Closterium Moniliferum, Cynthia Lehua Warnock Christensen Mar 1990

The Effect Of Plant Growth Regulators On The Growth Of Closterium Moniliferum, Cynthia Lehua Warnock Christensen

Dissertations and Theses

Physiologic responses to Gibberellic Acid (GA), 1-Naphthalene Acetic Acid (NAA), Benzylaminopurine (BAP), and Abscisic Acid (ABA), suggest that Closterium moniliferum has the ability to utilize these plant growth factors. The growth promoters NAA and GA both increased growth when added to the media. The cell division regulator BAP (a synthetic cytokinin). also had a promotive effect on growth. Abscisic acid was found to be inhibitive to growth.


The Vascular Flora Of Western Isle Of Wight County, Virginia, Gregory Michael Plunkett Jan 1990

The Vascular Flora Of Western Isle Of Wight County, Virginia, Gregory Michael Plunkett

Dissertations, Theses, and Masters Projects

No abstract provided.


Factors Related To The Occurrence Of Certain Prairie Graminoid Species In Black Hawk County, Iowa, Roadsides, Pauline Mary Drobney Jan 1990

Factors Related To The Occurrence Of Certain Prairie Graminoid Species In Black Hawk County, Iowa, Roadsides, Pauline Mary Drobney

Dissertations and Theses @ UNI

The native vegetation of Iowa was primarily tallgrass prairie and currently exists only in small isolated parcels, including some remnants occurring in roadsides. Roadside prairie remnants are important for historical, environmental, aesthetic, scientific, and economic reasons. Information about factors influencing the occurrance of roadside prairie vegetation could be useful to roadside vegetation managers in development of initial vegetation surveys and subsequent to restoration of roadside prairie vegetation.

This study was conducted to determine what factors most affected the percent coverage of prairie graminoids in roadsides; particularly soil moisture availability, drainage, soil disturbance, and availability of a prairie seed sources. Prairie …


Relative Effects Of Nutrient Enrichment And Grazing On Epiphyton-Macrophyte (Zostera Marina L.) Dynamics, Hilary A. Neckles Jan 1990

Relative Effects Of Nutrient Enrichment And Grazing On Epiphyton-Macrophyte (Zostera Marina L.) Dynamics, Hilary A. Neckles

Dissertations, Theses, and Masters Projects

Dissolved nutrient concentrations and invertebrate grazing activity regulate epiphytic biomass. Because epiphyton may limit light and carbon at leaf surfaces and the consequent productivity of submerged macrophytes, factors which influence epiphytic biomass may indirectly affect macrophyte abundance. I measured the simultaneous effects of water column nutrients (ambient or 3x ambient concentrations of nitrogen and phosphorus) and grazing (presence or absence of epifaunal community) on epiphyton and macrophytes seasonally in eelgrass (Zostera marina L.) microcosms on lower Chesapeake Bay. Grazing was more important than nutrients in controlling accrual of total epiphytic biomass, although effects on epiphytic components varied; numbers of diatoms …


Gas Exchange Of Four Viburnum Species, Lisa Gayle De Berg Jan 1990

Gas Exchange Of Four Viburnum Species, Lisa Gayle De Berg

Dissertations and Theses @ UNI

In the natural environment, a plant's gas exchange and water use efficiency characteristics in response to environmental stresses such as vapor pressure deficit, temperature, light intensity, and water potential may vary according to physiological and morphological species differences, leaf types (deciduous or evergreen), and habitat types (northern and southern). In the field, laboratory, and growth chamber, the effect of vapor pressure deficit, temperature, and light intensity on gas exchange characteristics was investigated for four woody shrub species from the genus Viburnum. The species under investigation include: y. rhytidophyllum (northern evergreen), y. awabuki (southern evergreen), y. dentatum (northern deciduous), and y. …


Potential Mechanisms Related To Salt Tolerance In Bean Plants, Sandra Baumgartner Jan 1990

Potential Mechanisms Related To Salt Tolerance In Bean Plants, Sandra Baumgartner

Masters Theses

Phaseolus vulgaris (navy bean) and P. acutifolius (tepary bean) were grown hydroponically and stressed with -0.25 MPa NaCl for 9 days beginning 22 days after planting. Chloride and sodium distribution in leaves and roots as well as percent ion leakage as an indication of membrane integrity in leaves were determined. Chloride levels in NaCl treated plants were significantly higher than in controls. Chloride levels were not significantly different between plant parts or between plant species. Sodium distribution differed significantly between the roots of navy and tepary but not between the leaves of the two species. Navy root tissue contained twice …


Effects Of Lake Management On Chemical, Physical, And Phycological Characteristics Of A Hypereutrophic Reservoir, Kaye J. Surratt Jan 1990

Effects Of Lake Management On Chemical, Physical, And Phycological Characteristics Of A Hypereutrophic Reservoir, Kaye J. Surratt

Masters Theses

Lake Charleston is a 1.1 billion gallon capacity side channel reservoir which was constructed in 1982 as a public drinking water supply for the City of Charleston in Coles County, Illinois. Past studies of the lake indicated an increase in eutrophication and the capacity to support large algal populations. Recent lake management practices include copper sulfate applications as an algicide and aeration to reduce flavor and odor.

In order to assess present lake status and to evaluate the effectiveness of lake management practices, two lake sites were sampled on a weekly basis from May to October, 1989. Chemical, physical, and …


The Effect Of Growth Regulators On Rough Turf At Coles County Airport, Salliana Ryan Erwin Jan 1990

The Effect Of Growth Regulators On Rough Turf At Coles County Airport, Salliana Ryan Erwin

Masters Theses

Twenty-five different combinations of plant growth regulators were evaluated with respect to their effectiveness in controlling rough turf at Coles County Memorial Airport (Illinois). Germination inhibition, control of plant height, suppression of seedheads, and phytotoxicity were considered. Postemergence applications were more effective than preemergence applications in the overall control of the vegetation present. Of the regulators tested, a combination of Escort (metsulfuron methyl; 1/3 oz/acre) and Oust (sulfometuron methyl; 1/4 oz/acre) provided the best postemergence control of both plant height and seedhead suppression, though associated phytotoxic effects were severe. Two other effective combinations were noted: Event (imazethapyr, imazapyr; 10 oz/acre) …