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Phylogeny Of The Characeae (Charophyta) And Biogeography Of Chara (Characeae) Inferred From Ribosomal Rna Genes., Susan T. Meiers
Phylogeny Of The Characeae (Charophyta) And Biogeography Of Chara (Characeae) Inferred From Ribosomal Rna Genes., Susan T. Meiers
LSU Historical Dissertations and Theses
This dissertation examined generic, subsection, and infraspecific aspects of the phylogeny of the Characeae, and biogeography of Chara subsections and Chara haitensis. These relationships were inferred from cladistic and maximum likelihood analyses of sequence data for 18S and ITS regions of nuclear-encoded ribosomal RNA genes. Morphologically-based phylogenetic hypotheses of Wood and Imahori (1965) and Khan and Sarma (1984) concerning the six extant members of Characeae were tested. The analyses supported: monophyly of family Characeae, tribe Chareae, and of Lamprothamnium; placement of Nitellopsis basal to tribe Chareae; and an unresolved relationship between Lamprothamnium and Chara. Neither the hypothesis of Wood and …
Interactive Effects Of Weeds And Defoliating Insects In Soybean (Glycine Max)., Charles Frost Grymes
Interactive Effects Of Weeds And Defoliating Insects In Soybean (Glycine Max)., Charles Frost Grymes
LSU Historical Dissertations and Theses
Field experiments were conducted to evaluate the influence of simulated insect defoliation and full season weed competition on soybean (Glycine max (L.) Merr.) growth and yield. Weeds were johnsongrass (Sorghum halepense (L.) Pers.), common cocklebur (Xanthium strumarium L.), and hemp sesbania (Sesbania exaltata (Raf.) Rybd. ex A. W. Hill) at 15, 3, and 12 plants/6 m of row. Simulated defoliation at R2 and R5 soybean growth stages was accomplished by removal of 0, 1, or 2 leaflets per soybean trifoliate, which approximated 0, 33, and 66% defoliation, respectively. Averaged across defoliation levels and stages, johnsongrass, common cocklebur, and hemp sesbania …
Growth And Mortality Of Fish Larvae In The Northcentral Gulf Of Mexico And Implications To Recruitment., Bruce Henry Comyns
Growth And Mortality Of Fish Larvae In The Northcentral Gulf Of Mexico And Implications To Recruitment., Bruce Henry Comyns
LSU Historical Dissertations and Theses
Extensive plankton collections were taken during September for several years along the northcentral Gulf of Mexico's inner continental shelf. Significant differences in growth rates were found for both vermilion snapper and Atlantic bumper larvae collected at stations where hydrographic conditions were similar, indicating the probable existence of small-scale patchily-distributed feeding conditions. Such variability in growth rates is probably inevitable given the high variability in the observed spatial and temporal distribution of surface chlorophyll a levels, macrozooplankton biomass, copepod abundance, and dispersion of fish larvae. Cruise estimates of mortality coefficients (Z) for larval vermilion snapper, red drum, and Atlantic bumper were …
Seasonal Changes In Gnrh Neurons And Effects Of Dietary Monoamine Precursors On The Hypothalamic-Gonadal Axis In House Sparrows (Passer Domesticus)., Christopher Andrew Meseke
Seasonal Changes In Gnrh Neurons And Effects Of Dietary Monoamine Precursors On The Hypothalamic-Gonadal Axis In House Sparrows (Passer Domesticus)., Christopher Andrew Meseke
LSU Historical Dissertations and Theses
Mechanisms modulating avian seasonal reproduction involve a complex interaction between exogenous environmental information and internal physiologic systems, such as functional changes in the hypothalamic-gonadal axis and changes in the influence of monoaminergic neurotransmitters on hypothalamic neuroendocrine cells. This project was undertaken to describe seasonal changes of the testes and immunoreactive-(ir)-gonadotropin-releasing hormone (GnRH) neurons in House Sparrows in southeastern Louisiana, and to examine the role of monoaminergic neurotransmitters in modulating seasonal reproduction through the use of dietary monoamine precursors. Testicular weights rapidly increased from February to March, peaked from April to July, when the seminiferous tubules were spermatagenically active and filled …
Metamorphosis Of The Hawaiian Stream Goby Sicyopterus Stimpsoni: A Structural, Functional, And Behavioral Analysis., Heiko Lars Schoenfuss
Metamorphosis Of The Hawaiian Stream Goby Sicyopterus Stimpsoni: A Structural, Functional, And Behavioral Analysis., Heiko Lars Schoenfuss
LSU Historical Dissertations and Theses
The endemic goby Sicyopterus stimpsoni is unique among five species of Hawaiian freshwater fishes because it undergoes rapid metamorphosis of cranial structures during postlarval development. These fishes are amphidromous and return after a prolonged stay in the ocean to streams where they are confined to estuaries until completion of cranial restructuring. Within 48 hours after entering fresh water, head width increases significantly, while total length and head length remains unchanged. Weight decreases by approximately 15% during this period. The upper lip enlarges greatly, and the mouth position shifts from terminal to nearly ventral. Shape analysis of radiographs taken from a …
A Search For Biologically Active Phytochemicals From Endemic Plants Of The Southeastern United States., Steven Lynn Robbs
A Search For Biologically Active Phytochemicals From Endemic Plants Of The Southeastern United States., Steven Lynn Robbs
LSU Historical Dissertations and Theses
In an investigation of allelopathy in the Florida scrub, bioassays with terpenes were performed against: Lactuca sativa, Rudbeckia hirta, Leptochloa dubia and Schizachyrium scoparium. Cineole was phytotoxic against Rudbeckia at 17 ppm and Lactuca at 165 ppm. (S)-camphor was phytotoxic to Rudbeckia at 1 ppm, Lactuca at 28 ppm, and Leptochloa and Schizachyrium at 134 ppm. (R)-Camphor, myrtenol and myrtenal were phytotoxic against Rudbeckia at concentrations of 28, 25 and 15 ppm respectively. Farnesol stimulated the germination of Schizachyrium at concentrations up to 50 ppm and at 100 ppm it reduced the radicle length of all test species. Geraniol stimulated …