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Natural History And Phytogeography Of The Loess Hills And Ravines, Lower Mississippi Embayment., Igor Igorevich Ignatov
Natural History And Phytogeography Of The Loess Hills And Ravines, Lower Mississippi Embayment., Igor Igorevich Ignatov
LSU Historical Dissertations and Theses
Although located near the middle of the Southeastern Coastal Plain, the hardwood forests of the Loess Hills of the Lower Mississippi Embayment have never been thoroughly studied or satisfactorily described in the literature. This dissertation is a case study of the biogeographic variation in the species composition and structure of the mature ravine hardwood forests within the southern section of the Loess Hills, from Warren County, Mississippi, south to East Baton Rouge and Vermilion Parishes, Louisiana, as affected by latitude, physiography, edaphic conditions, and disturbance. A parallel goal is, on the basis of the current biogeographic conditions and successional dynamics, …
Effects Of Low-Oxygen Atmosphere On The Growth And Development Of Arabidopsis Thaliana (L.) Heynh., Katrina Maria Ramonell
Effects Of Low-Oxygen Atmosphere On The Growth And Development Of Arabidopsis Thaliana (L.) Heynh., Katrina Maria Ramonell
LSU Historical Dissertations and Theses
Interest in the improvement of crop productivity through repression of photorespiration led to experimental growth of plants in low O2 and the surprising finding that reproduction is inhibited under these conditions. Using Arabidopsis thaliana (L.) Heynh. cv. Columbia, studies were undertaken to understand the mechanism behind oxygen control of plant development. The hypothesis that developmental changes observed in low O 2 are due to repression of the plant hormones ethylene and brassinolide (which require O2 for biosynthesis) was tested. Arabidopsis was grown for 35 days in Sun bags in one of five altered O 2 atmospheres (210, 160, 100, 50, …
Diallel Analysis And Molecular Genetics Of Ten Influential Upland Cotton Cultivars., Huangjun Lu
Diallel Analysis And Molecular Genetics Of Ten Influential Upland Cotton Cultivars., Huangjun Lu
LSU Historical Dissertations and Theses
The most influential cultivars from 16 cotton breeding programs were identified based on the analysis of the pedigree of 260 cultivars released between 1970 to 1990. A diallel cross containing ten parents and 45 F 1s (no reciprocals) was conducted to investigate general (GCA) and specific (SCA) combining ability for yield, yield components, and fiber properties of ten influential cultivars. The ten cultivars varied significantly for all the traits except for seed cotton yield and fiber length uniformity. Significant or highly significant GCA effects were detected for 11 of 12 traits studied. This indicates important additive gene action for the …
Bromoxynil And Pyrithiobac Weed Control Systems In Transgenic Bxn Cotton., Christopher Brett Corkern
Bromoxynil And Pyrithiobac Weed Control Systems In Transgenic Bxn Cotton., Christopher Brett Corkern
LSU Historical Dissertations and Theses
Field studies conducted in 1996 through 1998 evaluated grass control with the graminicides clethodim, fluazifop-P, quizalofop-P, and sethoxydim alone and in combination with bromoxynil. Sequential application of bromoxynil at 1.7 kg ai/ha 7, 3, and 1 day (d) before or 1, 3, and 7 d after each graminicide reduced antagonism of rhizome johnsongrass [Sorghum halepense (L.) Pers.] control when compared with bromoxynil plus clethodim, fluazifop-P, or quizalofop-P. Antagonism of johnsongrass control associated with bromoxynil and graminicide mixtures reduced cotton yield 17%. A 3 d or greater interval between bromoxynil and graminicide application was necessary to maximize cotton yield. Bromoxynil at …
Structural Characterization Of Beta Carbonic Anhydrases From Higher Plants., Michael H. Bracey
Structural Characterization Of Beta Carbonic Anhydrases From Higher Plants., Michael H. Bracey
LSU Historical Dissertations and Theses
It is the goal of this dissertation research to reveal some aspects of the physical nature of spinach carbonic anhydrase as a representative $\beta$CA using the techniques of sequence comparison, molecular biology, and biophysics. Though both $\alpha$ and $\beta$ carbonic anhydrases are zinc dependent metalloenzymes, it is clear that the two isoforms do not adopt the same mechanism for coordinating the active site metal. While $\alpha$CA binds zinc through three histidine ligands, $\beta$CA cannot due to a lack of evolutionarily conserved histidines. Instead, the $\beta$ family has adopted a ligand scheme incorporating a single histidine and two cysteines. This has …
Aerenchyma Development In The Freshwater Marsh Species Sagittaria Lancifolia L., Elisabeth Ellen Schussler
Aerenchyma Development In The Freshwater Marsh Species Sagittaria Lancifolia L., Elisabeth Ellen Schussler
LSU Historical Dissertations and Theses
Aerenchyma tissue consists of gas channels that provide a pathway for O$\sb2$ transport to waterlogged roots. Aerenchyma gas spaces are formed by cell separation or cell lysis during development. Light microscopy was used to determine how aerenchyma develops in Sagittaria lancifolia, a freshwater marsh species, when plants were grown in hydroponic solution. Petiole aerenchyma was formed by cell separation caused by differential cell expansion and division. In the root cortex, certain radial files of cells separated slightly from adjacent files and then lysed to form gas spaces. Development of root aerenchyma was characterized in S. lancifolia, Zea mays, and Oryza …
The Biology And Ecology Of The Yellowmargined Leaf Beetle, Microtheca Ochroloma Stal, (Coleoptera: Chrysomelidae) On Crucifers., Abdullahi Olod Ameen
The Biology And Ecology Of The Yellowmargined Leaf Beetle, Microtheca Ochroloma Stal, (Coleoptera: Chrysomelidae) On Crucifers., Abdullahi Olod Ameen
LSU Historical Dissertations and Theses
The biology and ecology of the yellowmargined leaf beetle, Microtheca ochroloma Stal, were studied on cabbage, Brassica oleracea var capitata L., collard, B. oleracea var acephala L., mustard, B. juncea Cosson, turnip, B. rapa L., and radish, Raphanus sativus L. The life cycle of the beetle consists of an egg stage, four larval instars, prepupal, pupal and adult stages. There were no significant differences in the effect of host plant on duration of development of immature beetles (p = 0.3353). The mean duration of development from oviposition to adult emergence ranged from 26.6 d on turnip to 27.5 d on …
The Role Of Seed Banks, Disturbance, And Sea Level Rise In Determining The Plant Community Structure Of Oligohaline Coastal Marshes., Andrew Hamilton Baldwin
The Role Of Seed Banks, Disturbance, And Sea Level Rise In Determining The Plant Community Structure Of Oligohaline Coastal Marshes., Andrew Hamilton Baldwin
LSU Historical Dissertations and Theses
Coastal wetlands worldwide are threatened by sea level rise, which is expected to affect the growth and survival of wetland vegetation by increasing water level and salinity. While the effects of salinity and inundation on adult vegetation of oligohaline marshes have been widely studied, the species composition of the seed bank and its response to elevated salinity and water level have not been examined. Additionally, the role of disturbances of different intensities in structuring marsh plant communities and possible interactions between disturbance and rising sea level have received little attention. Disturbances in coastal marshes include nonlethal disturbances such as fire …
Impacts Of Fire And Vertebrate Herbivores On Plant Community Characteristics And Soil Processes In A Coastal Marsh Of Eastern Louisiana, United States Of America., Mark Alan Ford
LSU Historical Dissertations and Theses
Both vertebrate herbivores and fire have long been known to have dramatic and important effects on wetlands. In the first part of this study, conducted in the Pearl River Basin coastal marshes of Louisiana, the interaction between the effects of mammalian herbivores, especially nutria and wild boar, and fire was examined in three marsh community types: those dominated by Sagittaria lancifolia, Panicum virgatum, or Spartina patens/Scirpus americanus. Overall, above-ground biomass was reduced by burning but increased by fencing. Richness only increased in plots that were both burned and fenced. In the three communities, only Scirpus americanus cover was enhanced by …
Role Of Hurricane Disturbance In The Dynamics Of The Southern Mixed Hardwood Forest: A Case Study In Northern Florida., William Bennett Batista
Role Of Hurricane Disturbance In The Dynamics Of The Southern Mixed Hardwood Forest: A Case Study In Northern Florida., William Bennett Batista
LSU Historical Dissertations and Theses
The objective of this dissertation was to characterize the role of hurricanes in the dynamics of old-growth Southern Mixed Hardwood Forests from the coastal plain of the northern Gulf of Mexico. First, we used data from five stands to describe the structure, composition, and disturbance regime of these forests. All five stands have Magnolia grandiflora and Fagus grandifolia among the dominant species, and have been affected by frequent but relatively mild hurricanes (4-6 per century, windspeed $<$200 km/h). Second, we examined the changes in tree recruitment, growth, and mortality occurred in Woodyard Hammock, northern Florida, after this forest was affected by Hurricane Kate in 1985. The analysis was based on data from biennial censuses of a 4.5 ha plot conducted between 1978 and 1992. Hurricane Kate produced extensive canopy disruption but limited tree mortality. This disturbance prompted a phase of increased recruitment, growth, and survival of understory trees, and decreased growth and survival of overstory trees. Release of small understory individuals appeared to be critical for the persistence of three short-lived dominant species, Pinus glabra, Ostrya virginiana and Carpinus caroliniana. However, persistence of the longer-lived dominants Magnolia grandiflora, Fagus grandifolia, Liguidambar styraciflua, Nyssa sylvatica, and Ilex opaca, appeared to depend primarily on resistance to hurricane damage. Third, we used matrix population models to test specific hypotheses about mechanisms of persistence of F. grandifolia in Woodyard Hammock. These models showed that, both before and after Hurricane Kate, this population was close to equilibrium. This result supported the hypothesis that persistence of F. grandifolia has resulted from hurricane resistance. Sensitivity analyses of the models suggested that the key for hurricane resistance has been the high survival of medium-size trees. Life-history strategies involving resistance and survival to hurricane disturbance, rather than release and rapid growth, appear to have been prevalent in these forests. However, the hurricane regime would have resulted in coexistence of species with the two types of strategy. Hurricanes would have been frequent enough to secure the persistence of species dependent on release, and mild enough not to compromise that of species dependent on resistance.
Molecular Systematics Of Red Algae., Jeffrey Craig Bailey
Molecular Systematics Of Red Algae., Jeffrey Craig Bailey
LSU Historical Dissertations and Theses
Phylogenetic analyses of nucleotide sequences for the nuclear-encoded small subunit ribosomal RNA (SSU) gene were used to test current hypotheses of relationships within the Corallinales and among the florideophycidaean orders of red algae. Analyses of SSU gene sequences indicate that the order Corallinales includes four major lineages. The Sporolithaceae is resolved as the earliest-diverging lineage within the order and forms the sister group to a monophyletic Corallinaceae. The molecular data also support the monophyly of the subfamilies Melobesioideae and Corallinoideae. The latter subfamily is inferred as sister to a fourth lineage including non-geniculate and geniculate species classified in the subfamilies …
Low Carbon Dioxide-Inducible Genes And Proteins In Chlamydomonas Reinhardtii., Zhi-Yuan Chen
Low Carbon Dioxide-Inducible Genes And Proteins In Chlamydomonas Reinhardtii., Zhi-Yuan Chen
LSU Historical Dissertations and Theses
At low CO$\sb2$ conditions, C. reinhardtii, like many other green algae, induces a CO$\sb2$ Concentrating Mechanism (CCM) to raise the internal Ci concentration. During the induction, at least five new polypeptides and six different genes are upregulated and some of the corresponding mRNAs or proteins are absent in high CO$\sb2$ requiring mutants. However the identities and functions of these genes are unknown. In this dissertation, I partially characterized four low CO$\sb2$ inducible genes and one low CO$\sb2$ inducible protein LIP-36. The complete cDNA sequences of clones 11I3 and 2I5 are 1311 bp and 985 bp, respectively. Neither of these two …
The Effects Of Timber Management Activities On Understory Plant Succession In Young Loblolly Pine (Pinus Taeda) Plantations., Donald Paul Reed
The Effects Of Timber Management Activities On Understory Plant Succession In Young Loblolly Pine (Pinus Taeda) Plantations., Donald Paul Reed
LSU Historical Dissertations and Theses
An understory vegetative succession study was conducted on the LSU Lee Memorial Forest near Bogalusa, Louisiana. Research blocks were established within fifteen-year-old overstocked loblolly pine (Pinus taeda) stands, in specific areas classified as with or without a history of prescribed burning for the current timber rotation. Silvicultural treatments involved precommercially thinning randomly selected blocks to various stand densities, along with the establishment of unthinned control areas. Growth rates of residual trees were determined from tree diameter measurements, on all timbered plots. Burn-history areas received a further treatment, involving the mechanical destruction of all timber on specified areas, followed by site-preparation …
Plant Species Diversity And Community Structure In A Louisiana Coastal Marsh., Laura Gough
Plant Species Diversity And Community Structure In A Louisiana Coastal Marsh., Laura Gough
LSU Historical Dissertations and Theses
The factors that control plant species diversity have been examined by many researchers, but with little consensus as to the causes of diversity patterns. Plant diversity has been correlated with disturbance, competition, soil resources, and other variables. In the research presented here, I investigated the relationship between plant species richness and biomass, competition, nutrient enrichment, flooding, salinity, and herbivory in field studies in Louisiana coastal marshes. Biomass alone was a poor predictor of richness in two Louisiana marshes. When environmental variables (flooding, salinity, and soil fertility) were included with biomass in a multiple regression model, 82% of the variance in …
Floral Development And Systematics Of The Caesalpinieae (Leguminosae: Caesalpinioideae)., Katherine Ellen Kantz
Floral Development And Systematics Of The Caesalpinieae (Leguminosae: Caesalpinioideae)., Katherine Ellen Kantz
LSU Historical Dissertations and Theses
The floral development of representatives from some of the informal taxonomic groups of the Caesalpinieae was examined. The floral developmental data was then used in a phylogenetic analysis in combination with more traditional morphological characters, including floral, vegetative and fruit characters. The analysis of 53 taxa and 84 characters produced 1215 equally parsimonious trees of length 386 (CI =.317, RI =.585, RCI =.186). Based on this analysis Caesalpinia sensu lato is not monophyletic, since at least two of the other genera in the Caesalpinia group are nested within Caesalpinia sensu lato. Of the infrageneric groups within Caesalpinia sensu lato, the …
Structure Elucidation And Chemistry Of Plant Natural Products In Search Of Bioactive Compounds., Heekyung Tak
Structure Elucidation And Chemistry Of Plant Natural Products In Search Of Bioactive Compounds., Heekyung Tak
LSU Historical Dissertations and Theses
A phytochemical study of regional members of five genera of the family Asteraceae was performed in search of bioactive natural products. The aerial parts of Garberia heterophylla, an endemic of the Florida central ridge scrub, were investigated and afforded the known guaianolide-type sesquiterpene lactone eupahakonesin, 2,6-dimethoxybenzoquinone, epifriedelinol and the novel diterpene, garberic acid. Aerial parts of Polymnia uvedalia provided three kaurane-type diterpenes, ($-$) kaur-16-en-19-oic acid, 3$\beta$-angeloyloxy-kaur-16-enic acid, 18-angeloyloxy-kaur-16-enic acid and two melampolides, enhydrin and 2$\sp\prime$, 3$\sp\prime$-dehydromelnerin A. The molecular structure of enhydrin was determined by single crystal X-ray diffraction. Verbesina virginica roots contained three eudesmane p-coumarate, 6$\beta$-p-coumaroyloxy-eudesm-4(15)-ene, 6$\beta$-p-coumaroyloxy-eudesm-4(3)-ene, 6$\beta$-p-coumaroyloxy-4$\beta$-hydroxyeudesmane and …
The Molecular And Morphological Systematics Of Subfamily Epidendroideae (Orchidaceae)., Malcolm Ray Neyland
The Molecular And Morphological Systematics Of Subfamily Epidendroideae (Orchidaceae)., Malcolm Ray Neyland
LSU Historical Dissertations and Theses
The current project undertakes the first molecular-based phylogenetic study of subfamily Epidendroideae (Orchidaceae). Approximately 1,200 nucleotide bases (from the 3$\sp\prime$ half of the ndhF chloroplast gene) for 34 orchid taxa, and a lilioid monocot, Clivia miniata, (Amaryllidaceae) were subjected to phylogenetic analysis using parsimony methods. Oryza sativa (Poaceae), a nonlilioid monocot was designated as outgroup. Using unweighted ndhF sequences, the strict consensus cladogram of 531 most-parsimonious trees supports the hypothesis that the large subfamily Epidendroideae is monophyletic, with Listera (Neottieae) as sister. Although subtribal-level relationships in subfamily Epidendroideae ate well resolved in this analysis, tribal-level relationships are resolved poorly. A …
Evolutionary Patterns In Proteaceae Based On Comparative Floral And Inflorescence Ontogenies., Andrew William Douglas
Evolutionary Patterns In Proteaceae Based On Comparative Floral And Inflorescence Ontogenies., Andrew William Douglas
LSU Historical Dissertations and Theses
Comparative floral and inflorescence ontogenies among Proteaceae are examined and a phylogenetic analysis based on principles of parsimony is presented. Comparative developmental and morphological investigations indicate that the fourmerous flowers are primitively simple. Each flower is composed of: a single series of four tepals that are initiated in two dimerous whorls (in most taxa); four stamens, each one initiated opposite a tepal and generally fused to the tepal at various heights due to zonal growth; and a single carpel. Ontogenetic studies reveal that the nectaries arise late in development and are not homologous to a reduced petal or stamen whorl. …
Life History Responses To Fire Season In A Clonal Herb, Pityopsis Graminifolia (Asteraceae)., John Stephen Brewer
Life History Responses To Fire Season In A Clonal Herb, Pityopsis Graminifolia (Asteraceae)., John Stephen Brewer
LSU Historical Dissertations and Theses
The effects of three fire seasons (May, August, and January) on reproductive success and clonal growth of a golden aster (Pityopsis graminifolia) were examined within experimental burn plots in a longleaf pine savanna in north Florida. Several factors influenced reproductive success in this species, including rates of floral induction and bud herbivory, clone fecundity, and seedling dynamics. Flowering was induced by fire, especially when it occurred in May or August. Fire season affected rates of floral induction and bud herbivory by as much as one to two orders of magnitude. Sizes of bolting shoots were also affected by fire season. …
The Effect Of Carbon Dioxide Concentration On Carbonic Anhydrase And Other Proteins In Chlamydomonas Reinhardtii., Mamta Rawat
The Effect Of Carbon Dioxide Concentration On Carbonic Anhydrase And Other Proteins In Chlamydomonas Reinhardtii., Mamta Rawat
LSU Historical Dissertations and Theses
Unicellular green algae, like Chlamydomonas reinhardtii, are able to grow photoautotrophically at low levels of CO$\sb2$. The efficient growth at low CO$\sb2$ levels is a reflection of the CO$\sb2$ concentrating mechanism that is induced when cells are adapted to low CO$\sb2$ levels. In this dissertation, the effect of CO$\sb2$ on carbonic anhydrase and other proteins in C. reinhardtii is discussed. In the first part of the dissertation, the isolation and purification of a new isoenzyme of carbonic anhydrase is reported. This carbonic anhydrase is present when cells are grown in high CO$\sb2$ but absent in low CO$\sb2$. It is located …
Specificity Of Chaperonin Groel Binding To The Precursor Of The Small Subunit Of Ribulose-1,5-Bisphosphate Carboxylase., Carmen Wheelock Dessauer
Specificity Of Chaperonin Groel Binding To The Precursor Of The Small Subunit Of Ribulose-1,5-Bisphosphate Carboxylase., Carmen Wheelock Dessauer
LSU Historical Dissertations and Theses
Although chaperonin-assisted protein folding has been studied in vitro by a number of investigators, the features of an unfolded or partially folded polypeptide that are recognized and bound by chaperonins are not known. I addressed this question using the precursor of the small subunit (pS) of ribulose-1,5-bisphosphate carboxylase as a model substrate for GroEL, the bacterial chaperonin. The precursor protein was expressed in E. coli as a C-terminal fusion to protein A. Protein A-pS (and any associated cellular proteins) was isolated by affinity chromatography. GroEL could be eluted from the fusion protein by ATP and either GroES or casein, consistent …
Photosynthetic Response To Elevated Carbon Dioxide Concentrations In The Aerenchyma Of Typha Latifolia L. Leaves., John Van Horne Constable
Photosynthetic Response To Elevated Carbon Dioxide Concentrations In The Aerenchyma Of Typha Latifolia L. Leaves., John Van Horne Constable
LSU Historical Dissertations and Theses
This study examined the importance of the leaf aerenchyma gas space as a CO$\sb2$ source for photosynthesis in Typha latifolia L. (broadleaf cattail). In the field there was a distinct diurnal pattern of CO$\sb2$ concentration ( (CO$\sb2$)) in the aerenchyma gas space. At dawn the aerenchyma (CO$\sb2$) was 4 to 18 times above atmospheric levels. By midday the aerenchyma (CO$\sb2$) declined to near atmospheric levels and increased again in the late afternoon. It is hypothesized that this diurnal pattern may be controlled by photosynthetic demand for CO$\sb2$. Aerenchyma gas space was estimated as $>$50% of leaf volume, and the …
Characterization Of Physiological Responses Of Suspension Cells From Alligator Weed (Alternanthera Philoxeroides (Mart.); Griseb) To An Abrupt Increase In Salinity., Gloria Balagtas-Burow
Characterization Of Physiological Responses Of Suspension Cells From Alligator Weed (Alternanthera Philoxeroides (Mart.); Griseb) To An Abrupt Increase In Salinity., Gloria Balagtas-Burow
LSU Historical Dissertations and Theses
Dark-grown suspension cells of alligator weed (Alternanthera philoxeroides (Mart.) Griseb) were established in Murashige and Skoog medium and used to characterize several cellular responses to an abrupt increase in salinity (0 to 200 mol m$\sp{-3}$ NaCl). The fresh weight and cell density of salt-treated cells of alligator weed more than doubled by 7 d. Cell viability declined to 77% by 1 d, but recovered to 86% by 7 d after salt treatment. These responses indicate that alligator weed cells survived and adapted to an abrupt increase in salinity. Osmotic potential ($\psi\sb\pi$) of salt-treated cells declined to the $\psi\sb\pi$ of the …
Determinants Of Mangrove Species Distribution In Neotropical Forests: Biotic And Abiotic Factors Affecting Seedling Survival And Growth., Karen Lee Mckee
Determinants Of Mangrove Species Distribution In Neotropical Forests: Biotic And Abiotic Factors Affecting Seedling Survival And Growth., Karen Lee Mckee
LSU Historical Dissertations and Theses
Mangroves are salt-tolerant trees and shrubs that dominate the intertidal zone in many tropical and subtropical coastal regions. These intertidal forests often exhibit relatively distinct and recurring patterns of species distribution. A series of field and laboratory experiments examined biotic and abiotic factors affecting survival and growth of three neotropical mangrove species: Rhizophora mangle (red mangrove), Avicennia germinans (black mangrove), and Laguncularia racemosa (white mangrove). A field survey across a mangrove island range in Belize revealed six vegetation zones based on differences in dominant canopy species, size and vigor of the trees, spatial position relative to the shoreline, and hydro-edaphic …
Phylogenetic Systematics Of The Ulvophyceae (Chlorophyta) Based On Cladistic Analyses Of Ribosomal Rna Genes And Morphology., Frederick William Zechman
Phylogenetic Systematics Of The Ulvophyceae (Chlorophyta) Based On Cladistic Analyses Of Ribosomal Rna Genes And Morphology., Frederick William Zechman
LSU Historical Dissertations and Theses
Cladistic analyses of non-molecular and nuclear-encoded rRNA sequence data provided the basis for hypotheses of relationships for the green algal class Ulvophyceae. Non-molecular data rooted with Chara support hypotheses which group the Chlorophyceae and Pleurastrophyceae with ulotrichalean and ulvalean Ulvophyceae. Analyses of rRNA sequence data group the siphonous and siphonocladous Ulvophyceae (i.e. Caulerpales, Siphonocladales, and Dasycladales) with the Chlorophyceae and Pleurastrophyceae. Although hypotheses supported by these independent data sets are incongruent, they suggest that the Ulvophyceae is not monophyletic. Based on rRNA sequences, pleurastrophycean taxa, which, like the Ulvophyceae, possess a counter-clockwise arrangement of flagellar basal bodies, are more closely …
Taxonomic Treatment Of Indigofera L. (Fabaceae: Faboideae) In The New World., Alan Wayne Lievens
Taxonomic Treatment Of Indigofera L. (Fabaceae: Faboideae) In The New World., Alan Wayne Lievens
LSU Historical Dissertations and Theses
The current taxonomic study of Indigofera (Fabaceae) as it occurs in the New World has several aims. The first addresses taxonomic and nomenclatural issues related to North American taxa. Because such issues have not been well understood for many of these taxa at various ranks, a synopsis of all taxa known to be referable to North America is presented along with a thorough discussion of nomenclatural issues (including synonymy) for each. This discussion is initially placed within the framework of the species groups proposed by Rydberg in 1923. A preliminary cladistic analysis of these North American species groups is presented. …
Effects Of Vertebrate Herbivory On Louisiana Coastal Marshes., Katherine Lynn Taylor
Effects Of Vertebrate Herbivory On Louisiana Coastal Marshes., Katherine Lynn Taylor
LSU Historical Dissertations and Theses
The disturbances of herbivory, simulated "eat-outs" (clipping and removal of above-ground biomass), and burning were examined for their effect on total biomass, individual species abundance, and species richness in several different marsh communities. Herbivory significantly reduced the total community biomass of all the marshes studied. Simulated "eat-outs" reduced the total biomass of the freshwater marsh but had no persistent effect on the total biomass of either the oligohaline or mesohaline marshes of the Pearl River. Both the oligohaline and the mesohaline marshes were able to recover from a removal of above-ground biomass (simulated "eat-out") within two years. The freshwater marsh …
The Molecular Systematics Of Unitunicate, Perithecial Ascomycetes., Joseph William Spatafora
The Molecular Systematics Of Unitunicate, Perithecial Ascomycetes., Joseph William Spatafora
LSU Historical Dissertations and Theses
Maximum parsimony analysis of partial sequences from the small subunit ribosomal DNA (ssrDNA) rejects the monophyly of unitunicate, perithecial ascomycetes (pyrenomycetes). The genera Kathistes, Pyxidiophora and Subbaromyces are separated from a large clade of relatively derived pyrenomycetes. This derived pyrenomycete clade is supported by a bootstrap confidence level of 100% and a decay index of $>$10 steps, and contains two subclades, A and B. Subclade A comprises the orders Clavicipitales, Hypocreales, Microascales and the genus Ceratocystis; subclade B consists of the Diaporthales, Sordariales, Xylariales and the genus Ophiostoma. The Clavicipitales is a sister taxon to the Hypocreales, which consists …
The Structural Organization Of Photosystem Ii Polypeptides., William Robert Odom
The Structural Organization Of Photosystem Ii Polypeptides., William Robert Odom
LSU Historical Dissertations and Theses
The structural organization of Photosystem II polypeptides has been investigated using the protein crosslinking reagent 1-ethyl-3-(dimethyl-aminopropyl)-carbodiimide (EDC), and a library of mono- and polyclonal antibodies. The first phase of this research was to generate the antibody probes against specific PS II polypeptides. A murine monoclonal antibody, FQC3, was characterized. It recognized the D2 protein of Spinacia oleracea L. The second phase of this research utilized antibodies against D1, D2, CPa-1, CPa-2, Cyt b$\sb{559}$, 33 kDa manganese stabilizing protein (MSP), 24 kDa extrinsic protein, and the 17 kDa extrinsic protein to identify PS II subunits crosslinked by EDC. Several intra-complex crosslinked …
Effects Of Propiconazole On Morphology, Development, And Epidemiology Of Rhizoctonia Solani, Causal Agent Of Rice Sheath Blight., Elly M. Van Eeckhout
Effects Of Propiconazole On Morphology, Development, And Epidemiology Of Rhizoctonia Solani, Causal Agent Of Rice Sheath Blight., Elly M. Van Eeckhout
LSU Historical Dissertations and Theses
Propiconazole was inhibitory to mycelial growth of Rhizoctonia solani in vitro. Sclerotial weight per colony was also reduced by propiconazole treatment but, in relation to total amount of mycelium, sclerotia formed earlier in 1 to 10 $\mu$g/ml plates than in control plates. Colony diameters from germinating sclerotia obtained from cultures growing at 0.5 to 10 $\mu$g/ml, were significantly greater than those of control colonies. Prolonged inhibitor activity resulted in increased branching, swollen or strongly tapered hyphal tips, formation of 'beaded' hyphae, and rupturing of hyphal walls when intrahyphal hyphae emerged. Abnormal fluorescent patches, representative of abnormal cell wall deposition, were …