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Loo, Min Jet. "Bryophytes conservation in Sabah." Doctoral thesis, Università degli studi di Padova, 2012. http://hdl.handle.net/11577/3422582.
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Kinabalu National Park (KNP) has the status as forest reserve class VI: virgin jungle forest in Malaysia. In 2000, it also has been recognized by UNESCO for its “outstanding universal values”. With an area size of 754 Km² and the highest peak at 4,095.2 metres, it provides a diversed habitat for ecologically important flora and fauna. Thus, from the Dipterocarp forest (lowland) to the sub-alpine forest (highland), each forest type offers different benefits to us. Ecologically speaking, montane forest (1200 - 2700m) is essential primarily as water catchment area though, this ecosystem often being forgotten due to its “low economic values” perceived by ordinary people. In fact, its economic value is high but since less people know about its free ecosystem services, it is unfairly assumed as less important in comparison to other type of forest, such as mangrove forest. In addition to that, the dominant communities inside the montane forest are bryophytes or in laymen’s term as mosses. In a nutshell, the functioning component of the moist and foggy forest is the mossy forest. As a reference to the bryodiversity in KNP, there are around 8000 species of bryophytes checklisted in the Malesian region.Kinabalu National Park (KNP) ha lo status di riserva forestale classe VI: giungla, foresta vergine in Malesia. Nel 2000, inoltre è stato riconosciuto dall'UNESCO per i suoi "valori universali" in circolazione. Con una dimensione di un'area di 754 km ² e la cima più alta a 4,095.2 metri, fornisce un habitat per la flora diversed ecologicamente importanti e fauna. Così, dalla foresta dipterocarp (pianura) al sub-alpino forestale (altopiano), ogni tipo di foresta offre diversi vantaggi a noi. Ecologicamente parlando, foreste montane (1200 - 2700) è essenziale in primo luogo come bacino idrografico, però, questo ecosistema essendo spesso dimenticata a causa dei suoi "valori bassi economici" percepiti dalla gente comune. Infatti, il suo valore economico è alto ma dal momento che meno gente conoscere i suoi servizi ecosistemici gratuiti, è ingiustamente assunto come meno importante rispetto ad altro tipo di foresta, come la foresta di mangrovie. In aggiunta a ciò, le comunità dominanti all'interno della foresta di montagna sono briofite o in termini laici di come muschi. In poche parole, il componente funzionamento della foresta umida e nebbiosa è la foresta di muschio. Come riferimento alla bryodiversity in KNP, ci sono circa 8000 specie di briofite checklisted nella regione Malese.
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Gabriel, Rosalina Maria de Almeida. "Ecophysiology of Azorean forest bryophytes." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326158.
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Lönnell, Niklas. "Dispersal of bryophytes across landscapes." Doctoral thesis, Stockholms universitet, Institutionen för ekologi, miljö och botanik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-100064.
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Dispersal, especially long-distance dispersal, is an important component in many disciplines within biology. Many species are passively dispersed by wind, not least spore-dispersed organisms. In this thesis I investigated the dispersal capacity of bryophytes by studying the colonization patterns from local scales (100 m) to landscape scales (20 km). The dispersal distances were measured from a known source (up to 600 m away) or inferred from a connectivity measure (1–20 km). I introduced acidic clay to measure the colonization rates over one season of a pioneer moss, Discelium nudum (I–III). I also investigated which vascular plants and bryophytes that had colonized limed mires approximately 20–30 years after the first disturbance (IV). Discelium effectively colonized new disturbed substrates over one season. Most spores were deposited up to 50 meters from a source but the relationship between local colonization rates and connectivity increased with distance up to 20 km (I–III). Also calcicolous wetland bryophyte species were good colonizers over similar distances, while vascular plants in the same environment colonized less frequently. Common bryophytes that produce spores frequently were more effective colonizers, while no effect of spore size was detected (IV). A mechanistic model that take into account meteorological parameters to simulate the trajectories for spores of Discelium nudum fitted rather well to the observed colonization pattern, especially if spore release thresholds in wind variation and humidity were accounted for (III). This thesis conclude that bryophytes in open habitats can disperse effectively across landscapes given that the regional spore source is large enough (i.e. are common in the region and produce spores abundantly). For spore-dispersed organisms in open landscapes I suggest that it is often the colonization phase and not the transport that is the main bottle-neck for maintaining populations across landscapes.At the time of the doctoral defence the following papesr were unpublished and had a status as follows: Paper 2: Epubl ahead of print; Paper 3: Manuscript; Paper 4: Manuscript
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Zhang, Li. "Diversity and conservation of Hong Kong bryophytes." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk:8888/cgi-bin/hkuto%5Ftoc%5Fpdf?B23316731.
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Zhang, Li, and 張力. "Diversity and conservation of Hong Kong bryophytes." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B30138103.
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Smith, Elizabeth. "Carbon accumulating mechanisms in lichens and bryophytes." Thesis, University of Newcastle Upon Tyne, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282765.
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Guêné-Nanchen, Mélina. "Régénération des bryophytes dans les tourbières perturbées." Doctoral thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/33616.
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La restauration écologique des tourbières se définit comme l’ensemble des procédés permettant d’assister à la régénération d’une tourbière qui a été dégradée, endommagée ou détruite. La gamme des tourbières perturbées qui nécessitent des actions de restauration est très diversifiée. L’étude de la régénération naturelle des écosystèmes perturbés a fréquemment été utilisée pour développer des méthodes de restauration qui sont adaptées aux types spécifiques de ces écosystèmes. Une compréhension plus complète des trajectoires de régénération, des contraintes environnementales et de dispersion, ainsi que des interactions interspécifiques, est directement reliée au développement de méthodes de restauration et à l’amélioration de nos connaissances sur la réponse des espèces et des communautés à des changements environnementaux. Cette thèse étudie la régénération de la végétation, plus spécialement des bryophytes, ainsi que les facteurs influençant leur régénération dans trois cas problématiques de restauration des tourbières perturbées. Premièrement, la régénération des communautés de bryophytes a été étudiée en fonction des conditions environnementales dans 28 tourbières minérotrophes des Territoires du Nord-Ouest et de l’Alberta ayant brûlé il y a un, deux ou cinq ans. Un changement de dominance a été observé entre les bryophytes pionnières (couvert moyen passant de 16 à 11 %) et les bryophytes de succession tardive (3 à 27 %) entre la 2e et la 5e année après le feu. La répartition et l’abondance des espèces de bryophytes semblent être contrôlées par leurs différences de capacité de régénération en lien avec leur stratégie d’histoire de vie, leur niche écologique et l’effet variable de la biomasse carbonisée. L’intégration de la notion de niche écologique chez les bryophytes de succession tardive ainsi que l’utilisation des espèces ayant un fort potentiel de régénération (comme Aulacomnium palustre et Ptychostomum pseudotriquetrum) devraient être considérées lors de l’élaboration des plans de restauration des tourbières minérotrophes. Deuxièmement, la régénération des sphaignes a été étudiée dans 25 sites donneurs (tourbières ombrotrophes où la végétation de surface a été récoltée pour servir de matériel de réintroduction) sur une chronoséquence de 17 ans en fonction des conditions environnementales et des pratiques de récolte. Les sphaignes dans les sites donneurs se régénèrent en moyenne en 10 ans, quoique des différences mineures dans la composition et l’abondance des espèces ont été observées entre les sites donneurs et les tourbières naturelles. Les espèces pionnières (p. ex., Eriophorum vaginatum), compétitives (p. ex., Sphagnum rubellum) et préférentielles des microhabitats plus humides (p. ex., Chamaedaphne calyculata) étaient plus abondantes dans les sites donneurs. Les pratiques de récolte avaient l’effet le plus important sur la régénération de la végétation, suggérant qu’il est possible d’accélérer la reprise des sphaignes en adoptant des pratiques de récolte appropriées. Des pratiques responsables consistent à éviter les sites donneurs très humides et la récolte durant le milieu de l’été lorsque les mousses ont un plus faible potentiel de régénération et lorsque le risque d’enlisement de la machinerie est élevé. Troisièmement, la régénération et le développement de tapis de sphaignes ont été étudiés dans deux types de tourbières restaurées et colonisées par des plantes pionnières de type graminoïde (Cypéracées). Dans le premier cas, le Carex aquatilis dominait un fen modérément riche restauré et formait des communautés denses avec beaucoup de litière. Dans le deuxième cas, l’Eriophorum angustifolium était dominant avec un faible couvert de litière dans une tourbière à sphaignes restaurée où la densité de la plante graminoïde avait été contrôlée par coupe répétée. Il a été démontré que l’effet des plantes graminoïdes sur les tapis de sphaignes était déterminé par leur litière plutôt que par la structure de la plante elle-même. En raison de l’ombre créée par la litière compacte, la présence d’une communauté dense d’une plante graminoïde accumulant beaucoup de litière comme Carex aquatilis ne semble pas être bénéfique pour développer des tapis de sphaignes productifs. La décision de contrôler les plantes graminoïdes pour accroitre le développement des tapis de sphaignes devrait prendre en considération, bien sûr, le couvert de la plante (non requis si le couvert moyen < 30 %), mais aussi sa forme de croissance (moins essentiel lorsque la plante pousse en tige unique), de même que ses potentiels d’accumulation de litière et d’envahissement (p. ex., Phragmites australis, Scirpus cyperinus). En somme, en plus de répondre spécifiquement à trois cas problématiques de restauration de tourbières perturbées, cette thèse fournit une compréhension améliorée des processus de régénération naturelle des écosystèmes de tourbières et des facteurs qui les influencent. Les résultats ont un lien direct avec le développement d’outils pour la restauration et avec l’approfondissement de nos connaissances sur les réponses des organismes et des communautés végétales aux changements de l’environnement.The ecological restoration of peatland is defined as all the processes permitting the regeneration of a peatland that has been degraded, damaged or destroyed. The landscape settings and types of peatlands that require restoration actions is very diverse. The study of natural regeneration of disturbed ecosystems has frequently been used to develop restoration methods that are adapted to specific types of ecosystems. A comprehensive assessment of regeneration trajectories and the environmental and dispersal constraints, as well as the interspecific interactions is directly related to the development of restoration methods and the improvement of our knowledge on the response of species and communities to environmental changes. This thesis studies the regeneration of vegetation, especially of bryophytes, and the factors influencing their regeneration in three problematic cases of restoring disturbed peatland. Firstly, the regeneration of bryophyte communities was studied against a range of environmental conditions in 28 minerotrophic peatlands in the Northwest Territories and Alberta that had burned one, two or five years ago. A shift of dominance between pioneer (mean cover from 16 to 11 %) and late successional bryophytes (from 3 to 27 %) was observed between the second and fifth year after the fire. Bryophyte distribution and abundance were controlled by the species difference in terms of regeneration capacity related to their life history strategy, habitat niche, and the variable effect of the burned biomass. The integration of the ecological niche concept for late successional bryophytes and the use of species with a high potential of regeneration (such as Aulacomnium palustre and Ptychostomum pseudotriquetrum) should be considered during the elaboration of restoration plans of minerotrophic peatlands. Secondly, the regeneration of Sphagnum mosses was studied in 25 donor sites (peatlands where surface vegetation was harvested to supply reintroduction material) on a chronosequence of 17 years according to environmental conditions and harvesting practices. It takes on average 10 years for Sphagnum mosses in donor sites to recover, though minor differences in the species composition and abundance was observed between donor sites and natural peatlands. Pioneer species (e.g., Eriophorum vaginatum), competitive species (e.g., Sphagnum rubellum) and preferential species of wet microhabitats (e.g., Chamaedaphne calyculata) were more abundant in donor sites. Harvesting practices had the greatest effect on the regeneration of donor sites, suggesting that it is possible to speed up Sphagnum regeneration by choosing appropriate management practices. Best practices would be avoiding very wet donor sites and harvesting in the midsummer should be avoided when mosses are at their lowest regeneration potential and when the risk of machinery sinking is high. Thirdly, the regeneration and development of the Sphagnum carpets were studied in two experiments conducted in two types of restored peatlands colonized by pioneer graminoid plants (Cyperaceae). In the first experiment, Carex aquatilis dominated a moderately rich restored fen and formed dense communities with a lot of litter. In the second experiment, Eriophorum angustifolium was dominant with a low cover of litter in a restored cutover Sphagnum-dominated bog where the graminoid plant cover was controlled by repeated mowing. It was demonstrated that the effect of graminoid plants on the Sphagnum carpet was determined by the litter rather than by the structure of the plant itself. Because of the shade created by the dense litter, the presence of a community of a graminoid plant that accumulates a lot of litter such as Carex aquatilis is not beneficial for the formation of productive Sphagnum carpets. The decision to control graminoid plants to enhance the growth of Sphagnum carpets should consider the cover of the plant (not necessary when mean cover < 30 %), but also its life form (less necessary when the plant grows in unique stem), its litter accumulation and potential for invasion (e.g. Phragmatis australis, Scirpus cyperinus). In conclusion, this thesis, in addition to specifically address these three problematic cases, provides a more comprehensive assessment of the processes of natural regeneration of peatland ecosystems and of driving factors. The results have a direct link with the development of tools for the restoration of peatlands and with a deeper understanding of the responses of plants and communities to environmental changes.
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Djan-Chekar, Nathalie. "The bryophyte flora of Bridal Veil Falls, British Columbia : an analysis of its composition and diversity." Thesis, Online version, 1993. https://circle.ubc.ca/bitstream/2429/1348/3/ubc_1993_spring_djan-chekar_nathalie.pdf.
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Weibull, Henrik. "Bryophytes on boulders : diversity, habitat preferences and conservation aspects /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/99-3371261-6.pdf.
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Llewellyn, David J. "The role of bryophytes in an indoor air biofilter." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0015/MQ58353.pdf.
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Phillips, Samantha Justine. "The ability of bryophytes to withstand sulphur dioxide pollution." Thesis, University of Sheffield, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284357.
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McCarthy, Mirabai Rachel. "Bryophyte Influence on terrestrial and Epiphytic Fern Gametophytes." Oxford, Ohio : Miami University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1193256414.
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Rudolphi, Jörgen. "Bryophytes, lichens and dead wood in young managed boreal forests /." Uppsala : Dept. of Ecology, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200788.pdf.
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Callaghan, Des A. "The distributon of Bryophytes in Lancashire: patterns, causes and consequences." Thesis, Edge Hill University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493267.
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This thesis investigates the patterns, causes and consequences of bryophyte distributions in Lancashire (north-west England). At a habitat scale, it is shown that species are spatially clustered and exhibit similarities in their ecologies within clusters, related in particular to gradients in disturbance and soil moisture. At a landscape scale. altitude is most strongly associated with differences in species distributions, correlated with important changes in habitats, water availability, nutrient availability and substrate pH. Changes in the solid geology also had an important influence in North Lancashire, where large exposures of limestone exist. Also at a landscape scale, high species-richness was found to be associated with high water availability, low nitrogen deposition and high cover of broad-leaved woodland.
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Walters, Stephanie E. "The microbial decomposition of six species of New Zealand bryophytes." Thesis, University of Canterbury. Plant and Microbial Sciences, 2001. http://hdl.handle.net/10092/6878.
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Nutrient cycling and energy flow within various ecosystems has been the subject of many studies in the past. The influence bryophyte litter has on nutrient cycling has not been investigated extensively and research on nitrogen flow, in particular, is limited. In the following study the litter quality and decomposition characteristics of material from six New Zealand moss species was investigated using both laboratory and field studies. Ptychomnion aciculare, Hypnodendron comatum and Dicranoloma dicarpum were collected from Maruia Springs in the Lewis Pass Reserve and Hypnum cupressiforme, Breutelia pendula and Racomitrium pruinosum came from Cass near Arthur's Pass.
Differences between the six species and between the green (younger) and brown (older) fractions of the litter were investigated with respect to litter quality, decay rates and nitrogen mobilisation. Due to the lack of an obvious senescence cycle naturally dead moss litter was difficult to determine therefore comparisons between the older and younger material were made.
Moss litter is thought to be resistant to microbial degradation due to the chemical characteristics of the material Chemical analysis of the species showed a range of high C:N and C:P ratios (53-188 and 206-815 respectively), and that approximately 90% of the acid soluble nitrogen was derived from amino acids and proteinaceous compounds. The high percentage of amino acid and proteinaceous nitrogen indicates that the litter may be of high quality if the nitrogen is not complexed with other compounds causing it to become recalcitrant.
Decay rates (k) were determined from weight loss experiments giving a range of 0.23- 1.3. There was an observed increase in weight loss over time for all the litter types. Nitrogen mineralisation studies indicated that nitrogen was released (generally in the form of ammonium ions) by microbial activity over 180 days incubation. Nitrate was also observed which in some cases exceeded ammonium levels. Leaching of the litter yielded water-soluble compounds including high nitrogen levels. Water-soluble extracts were shown to support microbial growth.
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Burch, Jane Alison. "The response of bryophytes to elevated atmospheric deposition of nitrogen." Thesis, University of Sheffield, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369943.
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Granath, Gustaf. "Peatland Bryophytes in a Changing Environment : Ecophysiological Traits and Ecosystem Function." Doctoral thesis, Uppsala universitet, Växtekologi och evolution, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-165138.
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Peatlands are peat forming ecosystems in which not fully decomposed plant material builds up the soil. The sequestration of carbon into peat is mainly associated with the bryophyte genus Sphagnum (peat mosses), which dominate and literally form most peatlands. The responses of Sphagnum to environmental change help us to understand peatland development and function and to predict future changes in a rapidly changing world. In this thesis, the overarching aim was to use ecophysiological traits to investigate mechanisms behind the response of Sphagnum to elevated N deposition, and, processes connected to ecosystem shift and ecosystem function of peatlands. Regarding elevated N deposition, three experiments were performed at different scales (country-wide to greenhouse). Independent of scale and species, apical tissue N concentration increased with increasing N input until N saturation was reached. Maximum photosynthetic rate, a trait evaluating photosynthetic capacity, increased with N input and could be well predicted by tissue N concentration. Thus, the physiological responses of Sphagnum to N deposition are often positive and I found no evidence of toxic effects. Production did, however, not increase with N input, and results of the N:P ratio suggested that P limitation, and possibly other elements, might hamper growth under high N input. The effect of P limitation was, in contrast to current view, most pronounced in fast growing species indicating species specific responses to nutrient imbalance. I explored the puzzling, but historically frequently occurring, rich fen to bog ecosystem shift; a shift from a species-rich ecosystem dominated by brown mosses, to a species-poor one with greater carbon storage that is Sphagnum-dominated. The bog-dwelling species of Sphagnum grew well, to our surprise, when in contact with rich fen water but was not a strong competitor compared to rich fen Sphagnum species. If submerged under rich fen water (high pH), the bog Sphagnum species died while rich fen species of Sphagnum were unaffected. These results show that differences in two physiological traits (growth rate and tolerance to flooding) among species, can explain when a peatland ecosystem shift might occur. In the last study, the function of peatlands was related to trade-offs between traits and allometric scaling in Sphagnum. Results suggested that growth strategies are determined by the distribution of Sphagnum relative to the water table in order to minimize periods with suboptimal hydration. Allometric analyses stressed the importance of resource allocation among and within shoots (apical part vs. stem), although the allocation patterns in Sphagnum were not always consistent with those of vascular plants. Interestingly, data indicated a trade-off between photosynthetic rate and decomposition rate among Sphagnum species.
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Long, Joel Andrew. "Ultrastructure and cytochemistry of sporogenesis in two bryophytes, Notothylas and Takakia /." Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1251821251&sid=10&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Suren, Alastair M. "The ecological role of bryophytes in alpine streams of New Zealand." Thesis, University of Canterbury. Zoology, 1990. http://hdl.handle.net/10092/5717.
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The ecological roles of aquatic bryophytes in 2 small New Zealand alpine streams were investigated. The streams differed with respect to algal biomass and detrital inputs, reflecting their location either above the tree-line (Mouse Stream) or flowing through mountain beech forest (Tim's Creek). Streambed instability was also higher in the forested site.
Quantitative sampling of bryophytes and riffles over 18 months revealed the existence of discrete macroinvertebrate (>250 µm) and meiofaunal (i.e., <250µm) communities within bryophytes. Here, macroinvertebrate and meiofaunal densities in bryophytes were up to 10, and 24 times greater than in riffles at Mouse Stream, and up to 7, and 15 times greater at Tim's Creek.
Faunas colonizing non-edible bryophyte analogues were similar to those colonising real plants, suggesting that invertebrates colonise these plants for their nontrophic properties. Manipulations of artificial bryophytes altered quantities of potential food (i.e., periphyton and detritus) and degree of shelter (i.e., "stem" density) to ascertain the importance of these in regulating invertebrate colonization. Functional responses to these variables differed between species and between sites. Positive relationships existed between invertebrate density and algal and detrital biomass, and shelter at Mouse Stream; the trends at Tim's Creek were not as evident and were masked by increased streambed instability and flooding.
Assessment of bryophyte consumption by gut content analysis revealed that only three of 23 taxa examined contained >5% of bryophyte material in their guts. The cranefly Limonia hudsoni was the only taxa that appeared to graze bryophytes extensively. Lack of consumption may be related to that fact that bryophytes contained more refractory, and less "digestible" material than selected riparian vegetation, or to the presence of antiherbivore compounds within some species.
The importance of bryophytes in affecting energy inputs into streams was finally examined. Algal biomass was higher on structures mimicking bryophytes than stones, and biomass was higher above the tree-line than below. Natural bryophytes trapped more FPOM than riffles, and mimics at Tim's Creek trapped more FPOM than at Mouse Stream. Bryophyte biomass at both sites however was similar, reflecting the ability of these plants to tolerate a wide range of light regimes. Retention of introduced organic matter into streams was influenced by bryophytes, whereby streams with these plants retained material better than streams without.
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Lewis, Jason Edward James. "Bio-monitoring for atmospheric nitrogen pollution using epiphytic lichens and bryophytes." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/13573/.
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Nitrogen enrichment in sensitive habitats has become a matter of concern in recent years, and has led to the need to develop a bio-monitoring scheme that could be used by non-specialists to undertake site evaluation across the UK. Epiphytes are ideal candidates for such a project due to their high sensitivity to atmospheric pollutants. Indicator species analysis identified a comprehensive UK-specific list of epiphytic indicators for NH3 pollution in the UK that for the first time also included microlichens. A shortlist of easily identifiable, widely distributed indicator species was produced from these and used to trial the effectiveness of a frequency based scoring system. A simple, un-weighted frequency based scoring system founded on the Lichen Acidophyte Nitrophyte index was found to correlate strongly with NH3 concentrations in air. Assessment of other atmospheric chemistry and climate variables with the scoring system showed that NO2 concentrations in air and bark pH were confounding factors. The influence of pH was further validated by observations in a field experimentation plot where different N forms were applied. In order to address this, a regression equation was formulated that incorporated NH3, NO2 and bark pH to produce a predictive model that could potentially be used to evaluate site condition with respect to atmospheric N pollution, as defined by the combined effect of NH3 and NO2. Investigations into the biochemistry of an indicator species identified that rates of phosphomonoesterase (PME) activity were higher in N-sensitive species than N-tolerant ones. N-sensitive lichen thallus pH measurements for were also consistently more acidic than those of N-tolerant species, and closer to the observed pH optima of PME activity.
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Kelly, Martyn G. "Heavy metals and aquatic bryophytes : accumulation and their use as monitors." Thesis, Durham University, 1986. http://etheses.dur.ac.uk/7086/.
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An experimental study was made of accumulation and loss of heavy metals by the aquatic moss Rhynchostegium riparioides and of the processes involved. The information gained were used to assess the effectiveness of this species as a monitor. Growth of Rhynchostegium continued throughout the year with peaks in spring and autumn. There were positive correlations between growth and water and air temperatures. Strong differences in growth rates in the four streams were not related to nutrient or heavy metal concentrations. Various patterns of mesh bag were tested as containers for transplanted Rhynchostegium to be used as a monitor. No significant differences in accumulation by moss were found between boulders or bags, or in accumulation with different patterns of bags. Accumulation was reduced slightly at the centre of bags packed with large quantities of moss. The physiology of Zn accumulation was also studied. A large part of accumulation (> 70%) in the early stages (< 12 h) was in a form readily exchanged for competing cations such as Ca and Ni; over longer time periods there was significant accumulation into a more tightly bound compartment. There was no evidence that uptake into this latter compartment was under the direct control of the plant's metabolism. There was differential accumulation of Cr(III) and Cr(VI) in laboratory experiments; during a case study it was possible to "predict" the speciation of Cr in the water by the concentrations accumulated by the moss. These results confirm that bryophytes are useful as monitors of heavy metal pollution in a wide range of circumstances. A range of such applications are outlined, along with recommendations for standard methods for using moss bags.
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Faburé, Juliette. "Etude de l'accumulation et des effets des composés organiques volatils (BTEX) chez les bryophytes." Lille 2, 2009. http://www.theses.fr/2009LIL2S050.
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Les conséquences sanitaires et environnementales de la pollution atmosphérique sont devenues au cours des dernières décennies un des problèmes majeurs de notre société. Sensibilisée à cette problématique, la région Nord Pas-de-Calais a été l’une des premières régions à soutenir et à valoriser la biosurveillance végétale de la qualité de l’air. Les travaux scientifiques réalisés dans le cadre de cette thèse ont pour objectif d’étudier les phénomènes d’accumulation et les impacts des composés organiques volatils (COV) chez les bryophytes. Articulées autour de deux axes, les recherches menées visaient à étudier, d'une part, l'accumulation des benzène, toluène, ethylbenzène et xylènes (BTEX), d'autre part, des effets au niveau cellulaire, du benzène chez Tortula ruralis, par l'analyse des variations de l'expression de biomarqueurs de stress oxydant. Des expérimentations complémentaires in situ , sur le littoral dunkerquois, et en conditions contrôlées ont permis d'établir des phénomènes d'équilibre des concentrations en BTEX entre notre modèle végétal et l'air. In situ, les teneurs en BTEX chez les mousses sont fortement conditionnées par les paramètres météorologiques, et principalement la force des vents. De plus, les concentrations atmosphériques en particules PM10 favoriseraient l'accumulation des BTEX chez la mousse. Mais d'une manière générale, les mousses n'accumulent pas les BTEX de façon corrélée aux teneurs dans l'atmosphère. Concernant l'expression des biomarqueurs de stress oxydant, des variations naturelles des paramètres biologiques mesurés sont observées chez la mousse. Ces variations seraient liées à la nature poïkilohydrique des mousses, leur capacité de reviviscence et aux aptitudes qu'elles ont développées pour résister aux variations de leur état d'hydratation. Ainsi, les biomarqueurs de stress oxydant souvent recherchés dans les études d'écotoxicologie, ne seraient pas adaptés pour l'étude des effets chez les bryophytes terrestres.
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Sporn, Simone Goda. "Epiphytic bryophytes in natural forests and cacao agroforests of Central Sulawesi, Indonesia." Göttingen Georg-August-Univ, 2009. http://d-nb.info/1000139549/34.
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McIntosh, Terry T. "The bryophytes of the semi-arid steppe of South-Central British Columbia." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/27137.
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This dissertation provides keys and concise descriptions of the genera, species and varieties of bryophytes known from the semi-arid steppe region of south-central British Columbia. Thirty-seven genera and seventy-seven species are included. Detailed illustrations are provided for selected species. Local distribution maps are included for all the taxa.
Four of the species included here are new to North America: Crossidium rosei, Phaseurn vlassovii, Pottia cf. wilsonii and Pterygonerum kozlovii. In addition, the genera Crossidium and Trichostomopsis as well as eight species and two varieties are new to Canada. Five additional species are reported for the first time from British Columbia.
Distributions of the taxa in the study area are discussed at local and world levels. Local distributions are influenced most by substratum type, aspect and elevational change, and effects of disturbance. Most of the taxa are terricolous and restricted to or with apparent preference to one of five soil types. Many taxa are saxicolous, but distributions with respect to rock type could not be determined.
The regional bryoflora is compared also to temperate dryland bryophyte floras globally. Surprisingly, the regional flora has very strong affinities, at both the species and genus levels, not only to dryland floras in the North American southwest but also with the arid regions of Eurasia and North Africa. Although some of the taxa in these areas are widespread throughout the Northern hemisphere, many species express disjunctions between the arid regions. Two contrasting causes, long-distance dispersal and vicariance, are discussed with respect to the origin of the disjunctive patterns. In most instances vicariance appears a more likely cause of the disjunction, although this conclusion is highly speculative. If vicariance is a cause, then the disjunct taxa are probably ancient and conservative. Bipolar disjunctions are also discussed. Long distance dispersal as well as hop dispersal appear to be more likely causes of this type of pattern than vicariance.
Many of the taxa require critical taxonomic revision. This reflects the lack of research in arid regions. Suites of genera that are problematic include Grimmia, Schistidium and Coseinodon, and Phaseurn, Pottia, Desmatodon and Tortula. Also, at least 41% of the species pose particular taxonomic problems. Some possible solutions for these problems are suggested here.Science, Faculty of
Botany, Department of
Graduate
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Krzaczkowski, Lucie. "Recherche exploratoire de substances actives en pharmacologie antitumorale à partir des Bryophytes." Toulouse 3, 2008. http://thesesups.ups-tlse.fr/311/.
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Plus de 50% des médicaments utilisés aujourd'hui en chimiothérapie anticancéreuse sont des substances naturelles, dérivées ou inspirées de produits naturels isolés de plantes supérieures, micro-organismes et organismes marins. Ce travail est consacré à l'étude des Bryophytes, végétaux dits " inférieurs ", comme source potentielle de molécules actives sur la mitose. Le criblage de 237 échantillons sur un essai phénotypique de perturbation de la division cellulaire a révélé 44 extraits actifs. Le fractionnement bio-guidé de six extraits n'a pas permis de caractériser les substances actives. Nous avons montré que l'activité de certains extraits est en réalité portée par des organismes associés aux mousses. Les effets de sept extraits de mousses pour lesquelles l'activité est intrinsèque ont ensuite été évalués sur un essai de cytotoxicité, par l'analyse du cycle cellulaire en cytométrie en flux et par la caractérisation des anomalies cellulaires détectées avec l'essai phénotypique. Trois profils différents ont été identifiés incluant deux phénotypes inhabituelsOver half of the current anticancer agents in clinical use are natural substances or are derived from natural products mainly isolated from higher plants, micro-organisms and marine sources. The present work has focused on Bryophytes, considered as "lower" plants, as a potential source of compounds acting on mitosis. The screening of 237 samples using a phenotypic cell-based assay revealed forty-one extracts disturbing cell division. The bio-guided fractionation of six active extracts failed to isolate or identify the active substances. We showed that, in some cases, contaminants and/or closely associated micro-organisms might be involved in moss extract activity. Seven extracts from mosses displaying intrinsic activity were further studied using a cell viability assay, cell cycle analysis and quantification of abnormalities detected by the phenotypic assay. Three distinct pharmacological patterns, including two unusual phenotypes, have been identified
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Henry, Jason S. "Studies on cell wall composition in bryophytes across taxa, tissue, and time." OpenSIUC, 2021. https://opensiuc.lib.siu.edu/dissertations/1922.
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The plant cell wall is a vitally important interface connecting plant cells to their outside environment and neighboring cells. Acting as a hub for defense, signaling, and physiological processes, the plant cell wall was a crucial innovation in plant evolution. Current cell wall models are largely based on what has been observed in plants like Arabidopsis, Pisum sativum, Nicotiana tabacum, and Phaseolus vulgaris. These models are unable to consider the variety of polymers in a given wall, the mechanical and functional properties such polymers impart, and the complexity of interactions among polymeric cell wall constituents. This work deepened the understanding of wall composition of specialized walls that fall outside of the scope of current plant cell wall models. A detailed survey of cell wall polymer distribution in the transfer cell walls in three key bryophyte species the model moss Physcomitrium patens, hornwort Phaeoceros carolinianus, and liverwort Marchantia polymorpha was done utilizing histochemical techniques in the light and florescent microscopes coupled with immunocytochemical localization with monoclonal antibodies (MAbs) in the transmission electron microscope (TEM). This work demonstrated that the occurrence, abundance, and types of polymers differ among taxa and between the two generations, are more influenced by developmental and life history needs than the similar function of the cells in individual taxa. A notable difference between generations was seen in M. polymorpha with the LM2 and JIM13 MAbs targeting AGP epitopes. However, findings in P patens appear to lack the differential labeling observed in both M. polymorpha and P. carolinianus. Using these same techniques, the walls and matrices involved in the process of spermatogenesis were examined in the moss P. patens and noted differences in abundance and location of cell wall polymers during sperm cell differentiation. Another notable finding of this work was that high concentrations of arabinose as components of AGP and pectins are important in the walls of P. patens during the process of spermatogenesis. The final study focused on utilizing herbarium specimens to explore the application of immunogold localization on dried collections of the moss Polytrichum up to 100 years old. The studies compiled in this dissertation demonstrate that the major cell wall components, cellulose, pectins, hemicelluloses, and callose, are constituents of special walls in three bryophytes, but they are differentially expressed within cell types and across these plants. Taken together, these works contribute significant new data on the composition of plant cell walls by focusing on bryophytes and the unique cell walls vital to the life history processes of spermatogenesis and placental function. These findings also show that both field-collected and herbarium samples are successfully labeled with MAbs at the TEM level, unlocking the potential for further studies across time and taxa using plant collections.
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DE, AGOSTINI ANTONIO. "Ecophysiological responses of bryophytes and orchids to environmental pollution: an integrated approach." Doctoral thesis, Università degli Studi di Cagliari, 2022. http://hdl.handle.net/11584/335547.
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Environmental pollution is one of the largest threats to human societies. To deepen the relationships between plants and environmental pollution it is crucial to profit from plant biodiversity in the control and mitigation of environmental pollution whilst simultaneously preserving such biodiversity from the adverse effects of pollution. Plant–pollutant interactions are widely studied in the scientific literature. However, studies focusing on natural populations facing polluted environments are rare. In this scenario, mosses and orchids (the two groups discussed in the present thesis) are even less studied in their adaptive mechanisms for coping with environmental pollution. Mosses and orchids respectively belong to the Bryophyta (sensu lato) and Angiospermae taxa, the former being non-vascular cryptogams whilst the latter are vascular flowering plants. The two plants belong to phylogenetically distant groups (at the antipodes of the evolutionary path of land plants) and their ecophysiological relationships with environmental inorganic pollutants (i.e. heavy metals) and their survival strategies were studied herein. The two groups considered were found to occur naturally in environments featured by severe heavy metal pollution due to previous mining activity. The metallicolous populations of orchids and mosses were characterised by several morphometric, physiological and ecological parameters and then compared with unpolluted control populations. The studied metallicolous populations were found to be different from control populations due to the adaptive process that allowed the colonisation of such extreme environments. The observed differences between metallicolous and control populations are as follows: i) varying dimensions of adult individuals and seeds (orchids), ii) alterations in basal levels of metabolites and photosynthetic efficiency (mosses and orchids) and iii) differential early seed development. The present thesis also focused on the use of plants as biomonitors of environmental pollution. The reliability of the moss bag technique was evaluated by analysing accumulation values measured during an extensive biomonitoring campaign conducted in the vicinities of an oil refinery. Obtained results not only confirmed the reliability of the biomonitor species and the adopted biomonitoring technique but also provided evidence regarding the influence of several experiments and ecology-related factors on accumulation values. Both focal points of the present thesis (the study of naturally occurring metallicolous populations and the biomonitoring of environmental pollution) reveal that plants are extremely useful tools in the control of environmental pollution and the study of the biosphere–pollutant interaction at the individual and ecological levels.
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Christmas, Martin. "Phosphorus dynamics in the Swale-Ouse river system." Thesis, Durham University, 1998. http://etheses.dur.ac.uk/4670/.
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A study was made of the phosphorus ecology of the Swale - Ouse river in northern England. It ranges from a stream draining a peat moorland to a mature river influenced by urbanisation (estimated population 250 000) and intensive agriculture. The aims were to assess the concentration and variability of aqueous N and P on spatial and temporal scales, and the response of two common mosses, Fontinalis antipyretica and Rhynchostegium riparioides, to those changes. Key aspects included analysis of water chemistry, internal nutrient contents of mosses, and 'surface' phosphatase activity. The rate of activity of m situ plants was measured over an annual period, in conjunction with short-term studies of transplanted populations. Studies of phosphatase activity in the water also were carried out to assess the biological cycling of phosphorus. Aqueous total phosphorus and total dissolved nitrogen concentration increased on passing down the river. In the upper reaches, total phosphorus comprised equal contributions of dissolved organic and inorganic phosphorus, which were almost certainly derived from diffuse sources. Further downstream, total phosphorus was almost entirely comprised of inorganic phosphorus from point source inputs. The nitrogen and phosphorus content of Fontinalis antipyretica and Rhynchostegium riparioides increased on passing downstream, consistent with the water chemistry. The rate of phosphomonoesterase activity of both mosses was high in the upper reaches of the river, and was inversely related to nutrient content. Fontinalis antipyretica sampled from streams draining peat moorland was shown to have a high phosphodiesterase : phosphomonoesterase ratio. A possible explanation for this is that peat is a potentially rich source of phosphodiester substrate, although increased phosphodiesterase activity may be a response to extreme phosphorus limitation. Transplantation of F. antipyretica showed that internal nutrient content and phosphatase activity respond to changes in ambient nutrients. Aqueous phosphomonoesterase activity was studied over a 12-month period. Laboratory and field studies suggest it plays an important role in the. phosphorus dynamics of the Swale - Ouse river system.
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Amblard-Gross, Géraldine. "Bryophytes et biomonitoring des retombées atmosphériques en métaux et éléments traces : caractérisation de la variabilité à différentes échelles d'utilisation." Metz, 2000. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2000/Amblard_Gross.Geraldine.SMZ0029.pdf.
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Les mousses, ou bryophytes, sont des organismes sentinelles de la pollution atmosphérique utilisés pour surveiller les variations spatio-temporelles des retombées atmosphériques en métaux et éléments traces à des échelles locales, régionales voire nationales. Les résultats du chapitre I mettent en évidence l'influence significative des techniques d'analyse multiélémentaires (AAN, ICP-MS) dans l'interprétation des cartographies élaborées à la suite de campagne européenne d'échantillonnage. L'étude de la variabilité spatiale d'échantillonnage du chapitre II met en évidence la faible précision de cet outil biologique pour détecter des variations spatiales de As, Ti, V, entre autre, mais autorisant la cartographie de Cu, Pb, Sb et Zn. Au chapitre III, un outil standardisé de bio-surveillance active est élaboré. Ce transplant baptisé Moss plate permet la conversion des concentrations de mousses vivantes en flux de poussières de différentes tailles pour les éléments Pb, Sb, Ti et Ba. Enfin, le chapitre IV étudie la localisation in vivo d'éléments non essentiels et essentiels le long des segments annuels de croissance des mousses par les méthodes SXRF (fluorescence X sous rayonnement synchrotron) et PIXE (émission X induite par les particules). Une accumulation préférentielle des éléments non essentiels et peu solubles est mesurée dans les segments les plus âgés. Ces répartitions préférentielles le long des brins sont observées sur des mousses échantillonnées in situ ainsi que sur les mousses transplantées et exposées pendant deux mois. Une dynamique de l'accumulation court terme des retombées est ainsi illustrée avec une localisation préférentielle des retombées récentes sur les parties âgées de la plante. Des échanges ioniques sont également mis en évidence par la méthode de fluorescence X à la suite du lavage des mousses avec une perte de K des segments âgés
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Poli, Dorothy Belle. "The role of auxin on the evolution of embryo development and axis formation in land plants." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2348.
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Rincon, Saucedo J. Emmanuel. "Experimental investigations of the ecology of bryophytes in calcareous grassland in northern England." Thesis, University of Sheffield, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338839.
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Kassel, Marlene. "Effects of climate change on freezing damage in three subarctic bryophyte species." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-130700.
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Climate change is expected to have a strong impact on subarctic ecosystems. Increased temperatures as well as altered precipitation and snow cover patterns are predicted to change species distribution and affect biogeochemical processes in the subarctic tundra. Bryophytes are an essential vegetational component in northern ecosystems, due to their high abundance and importance in many ecological processes. In this study the effects of elevation and altered snow cover on the temporal dynamics of freezing damage in three subarctic bryophyte species (Hylocomium splendens, Ptilidium ciliare, and Sphagnum fuscum) were studied in a snow manipulation field experiment in Abisko, during early spring. Soil temperature and field moisture of moss shoots were collected. A freeze-thaw incubation experiment was conducted to investigate the freeze-thaw cycle resistance of H. splendens and P. ciliare originating from habitats with two differing snow-cover thicknesses. Freezing damage differed significantly between the bryophytes species with P. ciliare experiencing the least and S. fuscum the highest damage. Damage was higher at the low elevation, possibly attributable to acclimation effects. Snow removal led to higher damage in moss shoots, but no interactions of the different snow cover treatments with elevation, species or time were found. Freezing damage increased over time and no recovery occurred, likely due to temporal patterns in soil freeze-thaw cycles during early spring. Soil freeze-thaw cycles were the main factor influencing damage in bryophytes after snow melt. Measured environmental parameters could not explain the entire variation in damage. Damage might additionally be attributable to increased UV radiation or disturbances by herbivores.
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Fuselier, Linda Catherine. "MAINTENANCE OF SEXUALLY DIMORPHIC PATTERNS OF GROWTH AND REPRODUCTION IN MARCHANTIA INFLEXA." UKnowledge, 2004. http://lib.uky.edu/ETD/ukybiol2004d00154/fuselier.pdf.
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Crowe, Celeste T. "Using the psbA gene as a measure in determining the phylogenetic relationship among bryophytes." [Johnson City, Tenn. : East Tennessee State University], 2002. http://etd-submit.etsu.edu/etd/theses/available/etd-0516102-110619/restricted/crowect053102a.pdf.
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Fabure, Juliette. "Étude de l'accumulation et des effets des composés organiques volatils (BTEX) chez les bryophytes." Phd thesis, Université du Droit et de la Santé - Lille II, 2009. http://tel.archives-ouvertes.fr/tel-00557714.
Full textAbstract:
Les conséquences sanitaires et environnementales de la pollution atmosphérique sont devenues au cours des dernières décennies un des problèmes majeurs de notre société. Sensibilisée à cette problématique, la région Nord Pas-de-Calais a été l'une des premières régions à soutenir et à valoriser la biosurveillance végétale de la qualité de l'air. Les travaux scientifiques réalisés dans le cadre de cette thèse ont pour objectif d'étudier les phénomènes d'accumulation et les impacts des composés organiques volatils (COV) chez les bryophytes. Articulées autour de deux axes, les recherches menées visaient à étudier, d'une part, l'accumulation des benzène, toluène, ethylbenzène et xylènes (BTEX), d'autre part, des effets au niveau cellulaire, du benzène chez Tortula ruralis, par l'analyse des variations de l'expression de biomarqueurs de stress oxydant. Des expérimentations complémentaires in situ , sur le littoral dunkerquois, et en conditions contrôlées ont permis d'établir des phénomènes d'équilibre des concentrations en BTEX entre notre modèle végétal et l'air. In situ, les teneurs en BTEX chez les mousses sont fortement conditionnées par les paramètres météorologiques, et principalement la force des vents. De plus, les concentrations atmosphériques en particules PM10 favoriseraient l'accumulation des BTEX chez la mousse. Mais d'une manière générale, les mousses n'accumulent pas les BTEX de façon corrélée aux teneurs dans l'atmosphère. Concernant l'expression des biomarqueurs de stress oxydant, des variations naturelles des paramètres biologiques mesurés sont observées chez la mousse. Ces variations seraient liées à la nature poïkilohydrique des mousses, leur capacité de reviviscence et aux aptitudes qu'elles ont développées pour résister aux variations de leur état d'hydratation. Ainsi, les biomarqueurs de stress oxydant souvent recherchés dans les études d'écotoxicologie, ne seraient pas adaptés pour l'étude des effets chez les bryophytes terrestres.
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Burger, Matthias [Verfasser]. "Functional in vivo analysis of RNA editing factors in bryophytes and angiosperms / Matthias Burger." Ulm : Universität Ulm, 2021. http://d-nb.info/1227450745/34.
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Lambert, Jean Fiona. "The phenology of selected Mediterranean-type climate bryophytes in relation to temperature and rainfall." Thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/26315.
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Mansouri, Katayoun. "COMPARATIVE ULTRASTRUCTURE OF APICAL CELLS AND DERIVATIVES IN BRYOPHYTES, WITH SPECIAL REFERENCE TO PLASMODESMATA." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/dissertations/484.
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This study focused on the primary cell wall constituents and plasmodesmata (PD) density in three mosses and four liverwort apical cells (AC) and immediate derivatives. The three mosses have tetrahedral apical cells and the liverworts possess tetrahedral, hemidiscoid and lenticular AC geometries. The primary cell wall in the studied taxa is comprised of two layers. A fibrillar layer, which is the outer wall layer, contains compacted cellulosic fibrils, and represents the two adjacent primary walls and middle lamella, the latter of which is rarely discernible. An electron-lucent inner wall layer abuts the plasma membrane. This layer has faint fibrous materials that extend from the plasma membrane to the fibrillar layer. Generally, as the cell wall ages it thickens, the fibrillar layer increases in width while the electron-lucent wall stays more or less consistent in width. In the four liverworts, the most recent wall of the AC has the highest PD density in the apical region regardless of AC geometry. As the walls elongate, primary wall is laid down between PD, separating them and resulting in lower densities and wider PD diameters in older walls. The season of fixation and whether plants were studied from nature or culture have an influence on AC ultrastructure. A developmental study of Physcomitrella patents gametophores in four stages, bud, 2-leaved, 7-8-leaved and ~20-leaved, reveals that the primary cell wall constituents change slightly during development. Specifically, LM5 a RG-I pectin antibody against the galactan branch epitope is only localized in the fibrillar layer of young water-conducting cells in the 7-8-leaved and 20-leaved gametophores. LM20, an antibody against HG esterified pectins, does not localize in any of the cell walls during development. The distribution patterns for AGPs (JIM13 and LM2) are consistent during gametophore development and predominantly localize on the electron-lucent layer and wall/plasma membrane interface. However, LM2 is mainly localized on the fibrillar layer in 7-8-leaved cell walls. AGPs also localize on element of the cytoplasm. LM6, an antibody against an RG-I pectin with arabinan branch epitopes, also localizes AGPs and because it expressed similar distribution patterns as JIM13 and LM2 on the cell wall, it likely localizes AGP in Physcomitrella. In addition, LM6 localizes pectins on the fibrillar layer similar to LM5 and LM19 for HG unesterified pectins. Callose predominantly localizes at the PD neck region. This study provides the first documentation of changes in size and shape of AC with age in Physcomitrella patens gametophores. The PD densities of gametophytes examined in this study fall into the lineage-specific network of PD (LPD) group designated for sporophytes of monilophytes and Selaginella (heterosporous lycophyte) with single ACs. Takakia lepidozioides leafy shoot has a tetrahedral AC with a highly curved free surface. This peculiar moss has mucilage hair (MH) associated with axil of phyllids. Mucilage hair in both species are 3-celled with a forth epidermal cell as the base. However, occasional 2-celled MH is seen in T. ceratophylla. The ultrastructure of MH has similarities with other mosses and liverworts.
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Horwath, Aline Barbara. "Epiphytic bryophytes as cloud forest indicators : stable isotopes, biomass and diversity along an altitudinal gradient in Peru." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610120.
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Denayer, Franck-Olivier. "Écotoxicité des éléments traces métalliques chez les bryophytes : mise au point d'un bryocapteur des retombées atmosphériques à l'aide de Ceratodon purpureus (Hedw.) Brid." Metz, 2000. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2000/Denayer.Franck_Olivier.SMZ0051.pdf.
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Cette recherche est axée sur l'écotoxicité des éléments traces métalliques à différents niveaux d'organisation des Bryophytes. Ainsi, dans une approche écotoxicologique pluridisciplinaire de la population métallique, nous abordons chez les Bryophytes, considérés comme des sentinelles de l'environnement, des aspects communautaires, physiologiques et cellulaires. Nous avons pu ainsi établir une échelle de diagnostic de la contamination des sols par l'observation des communautés bryophytiques et bryolichéniques terricoles. Nous avons mis au point un bryocapteur des retombés atmosphériques à l'aide de Ceratodon purpureus. Cette Bryophyte ubiquiste présente une certaine capacité à tolérer les fortes concentrations en éléments traces métalliques mais arrive également à se développer sur des sols non contaminés. L'exposition de ce bryocapteur à des retombées en Cd, Pb et Zn (à proximité de Metaleurop, une usine de métaux ferreux située à Noyelles-Godault, Pas-de-Callais, France), nous a permis d'observer les réponses biologiques de cette Bryophyte par l'intermédiaire de biomarqueurs de stress oxydant. Le stress oxydant causé par les éléments traces métalliques au niveau cellulaire provoque la mise en place de mécanismes de compensation tels que l'augmentation de l'activité des superoxyde dismutases et de la biosynthèse du glutathion. Ce phénomènes sont très peu étudiés en bryologie et permettent la mise en place d'outils de diagnostic précoce de la présence et des effets de polluants dans l'environnement. Cette recherche s'est effectuée dans le cadre du programme de recherches concertées, inscrit dans le contrat de plan Etat-Région 1994-1999
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Chmielewski, Matthew Wojciech. "Avian Dispersal Networks, Metacommunity Structure, and Bryophyte Community Assemblages." PDXScholar, 2019. https://pdxscholar.library.pdx.edu/open_access_etds/5096.
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Spatial processes have a profound influence on the structure and function of community assemblages. The dispersal of organisms from their place of origin to the location in which they live out their reproductive life is particularly important for plant communities, which generally cannot adjust their location post-germination. Connection between communities at a landscape scale can also influence species persistence, local and regional diversity, and functional turnover at the metacommunity scale. Animals have been shown to disproportionately deposit propagules in particular microsites in many plant species, facilitating the arrival of plants to appropriate niche-space. Birds are particularly notable seed dispersers, given their ability to fly long distances and their behavioral inclination toward using specific microsites within their habitat for foraging and nest building. Despite the known influence of animal behavior on plant dispersal outcomes, little work has been done to investigate the role of animals in dispersing bryophyte (moss, hornwort, liverwort) propagules. In order to examine how birds may affect bryophyte dispersal, I conducted two studies focused on understanding how bird species identity and behavior influence the bryophyte propagules they carry. In addition, I conducted a study to understand how metacommunity structure across a landscape can be influenced by focal spatial scale.
In the first study I examined how bird species and foraging behavior impact the topical load of bryophyte spores found on bird surfaces. In order to determine this, I captured passerine birds in mist nets and swabbed them for spores. I found that spores were more abundant on passerine tails than legs, and that overall spore load was higher on larger birds. Thrushes in particular carried more spores than other groups overall. Bark and foliage foraging birds had more spores on their tails than ground foraging birds. From these samples I was able to germinate 242 individual bryophytes, demonstrating that carried spores were readily viable.
In the second study, I examined species-specific relationships between bryophytes and the birds carrying them. Swabs from captured birds were grown in the lab and bryophyte species were determined genetically. I used a bipartite network approach to determine the level of specialization of associations within the overall network, as well as how specialized the avian associations of individual bryophyte species were. I then used the phylogenetic distance of bryophytes found on individual bird species in order to assess how specialized the assemblages on a given bird species were compared with a null, random model. I found that bryophyte associations with birds were nonrandom, and that the extent to which those associations were specialized differed by bird foraging behavior. In addition, I found that the diversity of propagules on bird surfaces was significantly nonrandom, with the exception of those bryophytes found on Spotted Towhees.
In the final study, I examined the metacommunity structure of bryophytes at both patch and landscape scales across a relict landscape of Valdivian forest in North-Central Chile. This landscape consists of distinct natural patches of forest maintained by coastal fog deposition, surrounding by a dry matrix inhospitable to patch-resident bryophytes. I used quadrats to sample bryophyte species abundance at the base and at breast height of ten trees in each patch, in 20 patches across the landscape. I found that when considering the whole park as one metacommunity, the bryophyte community exhibited a Gleasonian structure, in which individual species turnover was idiosyncratic. Considering assemblages from both heights separately, a Clemenstian pattern was observed, suggesting that within each height compartment, turnover of species tended to happen together. Treating each patch as a metacommunity of individual community trees resulted in a wide variety of metacommunity structures across the park that did not reflect either longitude or latitude. Low canopy cover and small DBH resulted in structures reflecting random species loss. Underlying Shannon diversity did not explain differences in the observed structures.
This dissertation provides the first evidence that passerine birds carry bryophyte propagules, and that their individual species use of habitat and foraging behaviors are likely to influence the number and diversity of the bryophytes they are dispersing. This has implications for understanding disjunct species and genetic distributions observed in bryophytes that to date have lacked an explanatory mechanism for long distance directed dispersal. In addition, understanding how avian behavior may disperse propagules at a local to regional scale may provide better insight into the trajectory of bryophyte recruitment on impacted landscapes. I also found that assignation of metacommunity structure is sensitive to spatial scale in bryophytes. Together, these findings increase our understanding of the role that spatial processes play in forming bryophyte communities.
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Russell, Shaun. "Production ecology of bryophyte vegetation at Marion Island (Sub-Antarctic)." Thesis, Rhodes University, 1996. http://hdl.handle.net/10962/d1003793.
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The world's tundra regions can be considered as the last unexploited terrestrial biome on the earth's surface. Bryophytes contribute significantly to primary production and nutrient cycling in tundra habitats but received considerably less attention than the vascular plants during research for the Tundra Biome Project of the International Biological Programme in the 1970s. The IBP synthesis recognised this and called for more bryophyte production data and improved methodology in future studies. The synthesis also identitied the need for more information on within-site variability, energy/chlorophyll relationships and mineral nutrient studies where tundra bryophyte production patterns are concerned. Marion Island in the sub-Antarctic has an oceanic "tundra" type of vegetation, and the island offers the characteristics of an ideal "natural laboratory" for conducting fundamental ecological research particularly in the field of primary production and energy flow. Studies at Marion Island paralleled those of the IBP but also concentrated on the vascular component of the vegetation. Bryophytes contribute up to 60% of the biomass and 90% of plant cover in the mires that dominate the well-vegetated coastal plain of Marion Island. Following the termination of IBP research therefore it was decided to extend these studies during the 1980s by measuring growth and characterising the major factors influencing growth patterns in Marion Island bryophytes. In this thesis information is given on the physical and biotic environment of Marion Island. Data is presented on the cover, biomass, seasonal and annual production values, and turn-over rates (decomposition) of 15 bryophyte species found across the full range of habit at types at Marion Island. An analysis is also made of growth-associated variables viz. soils, climate, plant energy, chlorophyll. water and mineral nutrient contents. Production was found to be related broadly to moisture-related variables, overlain by nutrient factors in some instances. Higher absolute production figures were obtained than at other tundra sites and interesting phenological data are discussed. The results suggest that decomposition is controlled mainly by tissue degradability factors and that decomposition is more significant than production in controlling biomass accumulation. A model is given for production/decomposition patterns across the range of habitat conditions at Marion Island. Several growth measurement techniques were tested and recommendations are made concerning methodology for future bryophyte production studies. By reference to ecological data collected during the study.
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Blöcher, Rolf. "Molecular evolution, phylogenetics and biogeography in southern hemispheric bryophytes with special focus on Chilean taxa." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=973439440.
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Sporn, Simone Goda [Verfasser]. "Epiphytic bryophytes in natural forests and cacao agroforests of Central Sulawesi, Indonesia / Simone Goda Sporn." Göttingen : Georg-August-Univ, 2009. http://d-nb.info/1000139549/34.
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Whitelaw, Mari. "Diversity and distribution of epiphytic bryophytes in apple orchards : relationship with tree and substrate variables." Thesis, University of Hertfordshire, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.629457.
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Orchards are biodiversity hotspots, home to a wide range of organisms including epiphytic bryophytes and lichens. However, the area of the UK given over to orchards has become considerably reduced; these habitats are under threat. In response to this, Traditional Orchards are now included as a priority habitat in the UK Biodiversity Action Plan. Local Habitat Action Plans have been produced. It is important that the factors which cause orchards to be such biodiverse habitats are understood in order to facilitate the management of newly planted and restored orchards. Surveys across 7 orchards were carried out, six in Hertfordshire and one in Cambridgeshire. A total of 141 apple trees were surveyed. Epiphytic bryophyte species were recorded, and in 7 of the surveys the cover of individual species was also included. 26 species of epiphytic bryophyte were recorded. There was a high level of similarity in species composition between the orchards, however this was much reduced when relative species cover was taken into account. In order to assess the overall diversity in order to compare orchards, the optimal number of trees to sample was found to be 10. Within the same orchard, significant differences in number of bryophyte species per tree and bryophyte cover were found between two varieties of apple tree, Ashmead's Kernal and Newton Like. This was accompanied by significantly different bark pH and nitrogen concentrations. However, pH was found to be of low importance in explaining the distribution of epiphytic bryophytes on Bramley trees across orchards. In vitro experiments found that low pH inhibited spore germination and growth in the species Brachythecium ve!utinum, Rhynchostegium confertum, Orthotrichum affine and Bryum capillare. High concentrations of nitrogen inhibited spore growth but not germination in the species Orthotrichum affine. The in-depth surveys of Bramley trees showed that across orchards, tree structure, as determined by management, explained about 10% of the observed variation in bryophyte cover. Within that, trunk girth and distance to nearest neighbouring orchard trees were the most important factors. Site was found to be the strongest influence on epiphytic bryophyte distribution in the orchards.
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BREUIL, SEE ANNE. "Criteres ultrastructuraux d'anhydrobiose et de reviviscence de thalles d'hepatiques du genre riccia l. (marchantiales - bryophytes)." Paris, EPHE, 1995. http://www.theses.fr/1995EPHE3002.
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Une importante recherche bibliographique a permis de faire une synthese des principales connaissances sur la reviviscence et de discuter les implications biologiques de ce terme. Afin de pouvoir etablir des criteres ultrastructuraux d'anhydrobiose et de reviviscence chez des hepatiques du genre riccia, des caracteristiques cytologiques des differents tissus des thalles en vie active ont tout d'abord ete determinees. Cette analyse a revele l'existence de cellules jamais signalees jusqu'a ici: les cellules rhizoidogenes, a l'origine des rhizoides. Puis, l'etude ultrastructurale de thalles desseches, conserves en herbier depuis 15 jours a 50 ans a permis de distinguer des manifestations cellulaires de senescence, variables en intensite, notamment en fonction de la nature du tissu, des conditions de dessiccation et de la duree de conservation des echantillons. Les differentes methodes de rehydratation utilisees confirment l'importance de cette phase sur le maintien de l'aptitude a la reviviscence. Le suivi ultrastructural de thalles rehydrates provenant des memes lots que ceux d'echantillons desseches deja etudies, a permis de differencier les hepatiques viables des hepatiques non viables. Des criteres d'anhydrobiose et de reviviscence ont ete determines. Ce travail montre egalement les sequences de reactivation cellulaire suivies chez des thalles conserves depuis quelques mois, mais aussi pour des cas extremes de thalles gardes en herbier depuis 25 ans. L'importance du nucleole au cours de la reviviscence et ce, des les premieres minutes de rehydratation, est soulignee, notamment dans les cellules meristematiques apicales et rhizoidogenes. La comparaison des resultats obtenus avec ceux tires de la synthese bibliographique, permet de redefinir la notion de reviviscence
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Gallissot, Brigitte. "Mise en évidence du potentiel bioaccumulateur des bryophytes aquatiques vis-a-vis des PCB et des pesticides organochlores : étude in situ et en laboratoire : proposition de grilles d'évaluation de la contamination par les organochlorés." Metz, 1988. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/1988/Gallissot.Brigitte.SMZ8813.pdf.
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La pollution organochlorée de quelques cours d'eau français (Seine, Isère, Rhin, Rhône) a été etudiée a l'aide de bryophytes autochtones et implantées. L'analyse des échantillons a permis de localiser précisément diverses sources de pollution par le PCB, le lindane et ses isomères, l'HCH et le DDT et ses métabolites. L'implantation sur des sites particulièrement contaminés a montré la bonne résistance des bryophytes à une pollution multiforme (289 ppm de PCB dans des mousses implantées dans un effluent industriel, 67 ppm de DDT et ses métabolites dans les mousses du Drac de Grenoble). Une durée de transfert de 6 jours semble suffisante pour obtenir une bonne analogie entre les concentrations en micropolluants dans les mousses autochtones et celles des transférées. La moitié des concentrations à l'équilibre est atteinte en 24 heures. Les cinétiques d'accumulation et de relargage des PCB par les bryophytes ont été étudiées in situ et en laboratoire. L'accumulation est rapide et l'équilibre est atteint après 10 jours d'incubation. La dépuration est lente. En 17 jours de relargage, les bryophytes éliminent seulement 47% des concentrations initiales en PCB. Les différences interspécifiques sont inférieures à un facteur 2. Des grilles de qualité basées sur la contamination organochlorée des bryophytes aquatiques sont proposéesOrganochlorine pollution of french rivers (Seine, Isère, Rhône) is studied with autochthonus and implanted aquatic bryophytes. Analysis of PCB, lindane and isomers, HCB, DDT and its metabolites in mosses allows to localise different degrees of pollution in effluents. Implantation on particulary contaminated sites has shown a good resistance of mosses to a multiform pollution : 289 ppm of PCB in mosses implanted in a industrial effluent, 67 ppm of DDT and metabolites in bryophytes in Drac river close to Grenoble. Transfert during 6 days seems to be sufficient to obtain a good analogy between micropollutant concentrations in autochthonous and implanted mosses. Half of equilibrium concentrations is reached in 24 hours. Accumulation and depuration kinetics of PCB by aquatic bryophytes were studied in situ and in laboratory. Accumulation is rapid and the steady state is reached after 10 days of accumulation. Depuration is slow : in 17 days of depuration, bryophytes had eliminated only 47% of initial PCB concentrations. Interspecific differences don't exeed twice factor. Quality indexes based on organochlorine pollution of bryophytes are proposed
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Cavalcanti, Porto Katia. "Analyse floristique et écologique de la bryoflore d'une forêt de plaine et d'une forêt d'altitude moyenne dans l'état de Pernambuco (Brésil)." Paris 12, 1989. http://www.theses.fr/1989PA120035.
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Des etudes floristique et ecologique sur les bryophytes de deux reliquats de foret tropicale humide ont ete realises dans l'etat de pernambuco, dans la region du nord-est du bresil. Les forets, une de plaine et une d'altitude moyenne se situent, respectivement, dans les reserves de saltinho, a rio formoso et de brejo dos cavalos, a caruaru. 170 especes de bryophytes ont ete repertoriees. Elles appartiennent aux anthocerotae (2), aux hepaticae (89) et aux musci (79). L'auto-ecologie des bryophytes recoltes est commentee dans une liste qui contient pour chaque taxon des observations d'ordre morphologique et phenologique, precise la forme de croissance, le substrat, le macrohabitat et la distribution geographique. L'etude comparative des deux reserves met en evidence que brejo dos cavalos est floristiquement plus riche en bryophytes que saltinho. L'analyse des principaux facteurs ecologiques demontre que la temperature plus faible en altitude, associee a un apport d'humidite additionnel par les vents humides, cree des conditions plus favorables a la vie des bryophytes a brejo qu'a saltinho, malgre un taux de precipitation plus reduit
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Branch, Traci L. "Pattern and distribution of RNA editing in land plant RBCL and NAD5 transcripts." Akron, OH : University of Akron, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1163792182.
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Thesis (M.S.)--University of Akron, Dept. of Biology, 2006."December, 2006." Title from electronic thesis title page (viewed 12/31/2008) Advisor, Robert Joel Duff; Committee members, Richard Londraville, Francisco B. Moore, Amy Milsted; Department Chair, Bruce Cushing; Dean of the College, Ronald F. Levant; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
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Porada, Philipp [Verfasser]. "Process-based modelling of lichens and bryophytes and their role in global biogeochemical cycles / Philipp Porada." Mainz : Universitätsbibliothek Mainz, 2014. http://d-nb.info/1047249944/34.
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