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Effekte anthropogener Störung auf die Diversität kryptogamischer Epiphyten (Flechten, Moose) in einem Bergregenwald in Südecuador /Nöske, Nicole, January 2005 (has links) (PDF)
Thesis (doctoral)--Universität Göttingen, 2004. / Includes bibliographical references (leaves 106-117). Also available in PDF format.
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Epiphytic macrolichens in relation to forest management and topography in a western Oregon watershed /Berryman, Shanti D. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2003. / Typescript (photocopy). Includes bibliographical references (leaves 133-142). Also available on the World Wide Web.
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Distribution patterns and metapopulation dynamics of epiphytic mosses and lichens /Snäll, Tord. January 2003 (has links)
Thesis (doctoral)--Uppsala Universitet, 2003. / Includes bibliographical references (p. 28-33). Downloaded and printed Aug. 26, 2004; also available via the Internet.
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Allelopathic effects of bark phenols on epiphytic lichens /Koopmann, Ricarda. Unknown Date (has links)
Thesis (doctoral)--Universität Bonn, 2005. / Downloaded and printed Sept. 10, 2008. Includes bibliographical references (leaves 52-60). Also available via the internet.
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Diversity and growth of epiphytic macrolichens in northwestern Patagonian Nothofagus forests /Caldiz, Mayra S. January 2005 (has links)
Thesis (doctoral)--Swedish University of Agricultural Sciences, 2005. / Thesis documentation sheet inserted. Appendix reproduces four papers and manuscripts, three co-authored with others. Includes bibliographical references. Also partially available electronically via World Wide Web in PDF format; online version lacks appendix.
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Bryophyte Influence on terrestrial and Epiphytic Fern GametophytesMcCarthy, Mirabai Rachel 25 October 2007 (has links)
No description available.
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Ecophysiology of the cyanolichen Lobaria oreganaAntoine, Marie E. 30 October 2001 (has links)
This thesis consists of three manuscripts describing ecophysiological research on
the cyanolichen Lobaria oregana. The first manuscript includes a re-evaluation of
the assumptions underlying past estimates of N fixation by this species and
provides an estimate of annual N fixation at the Wind River Canopy Crane
(WRCC). Based upon litterfall data, canopy biomass data, N content of lichen
tissue, and published growth rates, L. oregana fixes 0.4-1.6 kg N₂ ha⁻¹ yr⁻¹. The
second manuscript presents a series of physiological response curves and a model
of N fixation by L. oregana. Temperature is the most important parameter
controlling nitrogenase activity in hydrated thalli. The model is used to predict
annual N fixation at the WRCC and at the H.J. Andrews (HJA) Experimental
Forest. Lobaria oregana fixes 1.4-1.8 kg N₂ ha⁻¹ yr⁻¹ at the WRCC, and low winter
temperatures often inhibit nitrogenase activity. Temperatures at the HJA are
slightly warmer during the winter, and L. oregana fixes 2.6-16.5 kg N₂ ha⁻¹ yr⁻¹
depending on its stand-level biomass. The third manuscript investigates the effects
of thallus water content, light, and temperature on CO₂ exchange in L. oregana.
This species shows a typical photosynthetic response upon rehydration, and like
other lichens it becomes light-saturated at low PAR levels. Positive net
photosynthesis in L. oregana occurs only between 1-12°C. High respiration rates
prevent carbon gain at warmer temperatures. The temperature constraints on carbon
gain and nitrogen fixation may explain some of the landscape distribution patterns
of L. oregana. / Graduation date: 2002
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Epiphytic diatom assemblages associated with South African kelps: Ecklonia maxima and Laminaria pallidaMayombo, Ntambwe Albert Serge January 2020 (has links)
Magister Scientiae (Biodiversity and Conservation Biology) / Kelp forests are dynamic and productive ecosystems which host large biodiversity of sessile
fauna and flora, including diatoms. These microalgae occur at the base of coastal marine
food webs and contribute substantially to the productivity of marine ecosystems. Diatoms
constitute one of the most common and species-rich groups of both phytoplankton and
phytobenthos. Possessing a unique silica cell wall, diatoms play a key role in the global
carbon and silicon cycles. As the changes in species composition of diatom communities are
a direct reaction to the combination of environmental factors prevailing in their ecosystems,
diatom analysis is widely and successfully used in biomonitoring of various environmental
conditions and paleoecological reconstructions.
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Identification and Optimization of the Antagonistic Potential of Native Spinach Microbiota towards Escherichia coli O157:H7Tydings, Heather Anne 07 July 2010 (has links)
Leafy greens such as spinach have been the object of several recent food-borne pathogen outbreaks. The purpose of this study was to isolate bacteria spinach epiphytic bacteria that inhibit growth of E. coli O157:H7, which we describe as antagonism. The mechanism of antagonism was investigated and we attempted to improve the antagonistic potential in vitro and on spinach leaves when cellobiose, a carbon source utilized by the antagonists but not E. coli O157:H7, was added.
There were larger culturable populations of bacteria on the leaves of savoyed cultivars compared to flat. From the isolated colonies, 47 displayed antagonism towards E.coli O157:H7, and were identified as members of 11 different genera and sixteen species. A representative isolate from each species was evaluated for three possible mechanisms of antagonism: acid production, secretion of an inhibitory compounds or secreted protease. The majority (14/16) produced at least a moderate level of acid. Two of these strains, Paenibacillus polymyxa and Pseudomonas espejiana, were found to secrete a non- protease antagonistic compound.
These antagonists varied in their reduction of E.coli O157:H7 numbers in vitro, but all significantly reduced numbers in 48 hours of co-culturing in nutrient rich media. Five antagonists resulted in a significant reduction in E.coli O157:H7 populations when co-cultured on spinach leaves. Application of cellobiose did not improve the amount of antagonism in vitro or on the leaf surface after 24 hours. / Master of Science
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Competência para a expressão da fotossíntese CAM em plantas de Guzmania monostachia (Bromeliaceae) em diferentes fases ontogenéticas / Competence for CAM photosynthesis expression in different ontogenétic stages of plants of Guzmania monostachia (Bromeliaceae)Hamachi, Leonardo 06 November 2013 (has links)
A Guzmania monostachia é uma espécie de bromélia heteroblástica, ou seja, na fase juvenil, ela apresenta a forma atmosférica e na fase adulta, ela adquire uma estrutura chamada de tanque, que pode armazenar água e nutrientes em momentos de seca esporádica. Ela também é reconhecida por ser C3-CAM facultativa, podendo ser induzida ao CAM através de estímulos ambientais como o a escassez d\'água. Estudos com outras espécies competentes para a expressão do CAM, há relatos de que tecidos jovens expressariam preferencialmente a fotossíntese C3 e passariam a expressar o CAM à medida que se tornassem maduros. No Laboratório de Fisiologia do Desenvolvimento Vegetal a indução do CAM em plantas adultas da espécie G. monostachia por déficit hídrico foi estudada e pôde-se constatar que essa bromélia possui folhas com regiões funcionais distintas: a porção basal seria responsável pela absorção de água e nutrientes e a porção apical encarregada de realizar, principalmente, a fotossíntese. Contudo, ainda não se possuía informação sobre como a ontogenia e as mudanças morfológicas estariam influenciando a competência para a expressão do CAM em folhas inteiras e nas diferentes porções foliares de G. monostachia. A fim de se caracterizar o CAM nesta espécie ao longo da ontogenia, foram selecionadas plantas em 3 fases ontogenéticas (Atmosférica, Tanque-1 e Tanque-2) e das fases Tanque-1 e 2 foram separados grupos de folhas representando 3 estágios de desenvolvimento (F1 - as 7 mais internas da roseta, F2- as 7 folhas seguintes da roseta e F3 - as 7 folhas localizadas mais na base da roseta). As plantas foram submetidas a 7 dias de déficit hídrico por meio da suspensão de rega. Outra coleta de material vegetal foi realizada com plantas Tanque-2 separando-se as folhas em grupos representando os mesmos 3 estágios de desenvolvimento utilizados no experimental anterior e dividindo-as em porções basal e apical. Medidas morfométricas foram feitas para caracterizar cada fase ontogenética. O teor de água dos tecidos das folhas foi determinado e o CAM foi detectado através do ensaio enzimático da PEPC, da MDH e da quantificação dos ácidos orgânicos (ácido cítrico e málico). As plantas Tanque-2 apresentaram mais que o dobro da capacidade de estocagem de água comparativamente às plantas Tanque-1. As plantas atmosféricas sofreram as maiores perdas de água em sua folhas (aproximadamente 50%); já as plantas com tanque tiveram decréscimos mais discretos no teor hídrico (em torno de 15%). Plantas de todas as fases ontogenéticas acumularam significativamente ácido málico durante a noite, evidenciando que, independente da ontogenia, as plantas foram competentes para expressar o CAM. De maneira semelhante, tanto as folhas mais jovens quanto as mais maduras exibiram acúmulos significativos de ácido málico, indicando que elas foram capazes de expressar o CAM nos 3 estágios de desenvolvimento escolhidos para este estudo. Portanto, no conjunto dos experimentais realizados, sugere-se que o fator mais importante para a expressão do CAM em plantas de G. monostachia seja o teor de água dos tecidos foliares e não a ontogenia. Plantas atmosféricas apresentaram a maior perda de água (aproximadamente 50%) concomitantemente à expressão do CAM. Já as regiões apicais dos grupos de folhas F1 das plantas Tanque-2 exibiram um decréscimo de 7% com acúmulo noturno de ácido málico e os grupos F2 e F3 perderam 12% da água de seus tecidos, resultando na inibição do CAM. Há indícios que o transporte de água nas plantas com tanque sob estresse hídrico ocorra das folhas mais maduras para as folhas mais jovens. Aparentemente, plantas jovens atmosféricas de G. monostachia possuem a capacidade de manter seu metabolismo mais ativo mesmo em condições que resultem em uma baixa quantidade de água nos tecidos foliares, indicando um certo grau de tolerância à seca. Ao contrário, nas plantas com tanque, essa capacidade parece não ser tão acentuada, sugerindo que esta fase esteja mais relacionada com estratégias de evitação à seca / Guzmania monostachia is a species of heteroblastic bromeliad, in other words, whereas in the juvenile phase, it assumes the atmospheric form, in the adult, it acquires a structure called a tank, by which water and nutrients can be stored in moments of sporadic drought. It is also recognized through being C3-CAM facultative, thus inducible to CAM through environmental stimuli, such as the lack of water. In the young plants of other species capable of CAM expression, there are reports of preferential C3 photosynthesis expression in young tissues, leading to CAM expression on reaching maturity. In the Laboratory of Plant Development Physiology, studies were made of CAM induction in adult plants of the species G. monostachia during the lack of water at times of drought. It was noted that this bromeliad possessed leaves with distinct functional regions: whereas the basal portion was responsible for the absorption of both water and nutrients, the apical was mainly responsible for photosynthesis. Nonetheless, there was no available information on how ontogeny and morphological changes could influence competence for CAM expression throughout the whole leaf, as well as in the different parts. In order to characterize CAM in this species throughout ontogeny, selection was concentrated on plants in the three ontogenetic phases (Atmospheric, Tank-1 and Tank-2), as well as in the Tank-1 and Tank-2 phases by separating groups of leaves representing the three stages of development in the rosette, viz., Stage1 - the seven inner-most leaves, Stage2 - the next seven, and Stage3 - the seven located more at the base. By suspending irrigation, all the plants were submitted to 7 days without water, whereupon further material was collected from Tank-2 plants. The leaves thus obtained were first divided into groups representing the same three developmental phases as used in the preceding experiment, and then separated into basal and apical portions. Morphometric measurement was applied to the characterization of each ontogenetic phase. Tissue water content in the leaves was defined, and CAM detected through PEPC enzymatic assaying, MDH, and organic acid (citric and malic) quantification. Tank-2 plants presented more than double the capacity to store water, when compared to Tank-1 plants. Whereas atmospheric plants underwent the greatest leaf-water loss (around 50%), the loss was less in those with tanks (around 15%). Significant nocturnal malic acid accumulation in plants in all the ontogenetic phases, placed in evidence plant competency for CAM expression, independent of the stage of development. Likewise, significant malic acid accumulation in both young leaves and more mature ones indicated their capacity for CAM expression in the three stages of development chosen for the present study. Thus, in the experiments carried out, it can be presumed that the most important factor for CAM expression in G. monostachia plants is leaf-tissue water content, and not ontogeny. Atmospheric plants presented the highest water loss (around 50%), which was concomitant with CAM expression. On the other hand, in the apical regions of Tank-2 plants, there was a drop of 7% in water content with nocturnal malic acid accumulation in stage-1 leaves, and a loss of 12% in tissue water in those in stage 2 and 3, with the consequential CAM inhibition. There is every indication that water-transport in tank plants undergoing water-stress occurs from more mature leaves to those younger. Apparently the more active metabolism in young G. monostachia atmospheric plants, even under conditions inducing low leaf-tissue water content, indicates a certain degree of drought tolerance. On the contrary, although this capacity in tank plants appears to be less accentuated, the tank phase is apparently more related to strategies for avoiding the effects of drought
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