Sökning: "nitrogen uptake"

Visar resultat 1 - 5 av 119 avhandlingar innehållade orden nitrogen uptake.

  1. 1. The nitrogen economy of mountain birch : As related to environmental conditions and genotype

    Författare :Martin Weih; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Betula pubescens ssp. czerepanovii; growth; nitrogen; subarctic; temperature; ultraviolet radiation; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : Responses of mountain birch growth to changed environmental conditions arestrongly affected by birch genotype, and nitrogen economy is a key factor influencingthe winter survival of first-year seedlings. These are some of the findings of a series ofstudies, in which growth, nitrogen economy and winter survival were analysed usingpot-grown seedlings of mountain birch (Betula pubescens ssp. LÄS MER

  3. 2. Responses of peatland vegetation to enhanced nitrogen

    Författare :Magdalena Wiedermann; Lars Ericson; Juul Limpens; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sphagnum; nitrogen; peatlands; soluble amino acids; gradient study; field experiment; Biology; Biologi;

    Sammanfattning : Human alteration of the global nitrogen (N) cycle has had major impacts on naturally N-limited ecosystems worldwide. Peatlands, dominated by peat mosses, Sphagnum species, represent one such sensitive ecosystem. LÄS MER

  4. 3. Nitrogen transformations in wetlands: Effects of water flow patterns

    Författare :Torbjörn Davidsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Hydrobiology; hydrology; infiltration; subsurface flow; surface flow; wetland; nitrogen; Denitrification; mineralization; nitrification; marine biology; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi;

    Sammanfattning : In this thesis, I have studied nitrogen turnover processes in watermeadows. A watermeadow is a wetland where water infiltrates through the soil of a grassland field. LÄS MER

  5. 4. Cyanobacterial Hydrogen Metabolism - Uptake Hydrogenase and Hydrogen Production by Nitrogenase in Filamentous Cyanobacteria

    Författare :Pia Lindberg; Peter Lindblad; Kornél Kovács; Uppsala universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Microbiology; cyanobacteria; biohydrogen; Nostoc; hydrogen production; hydrogen evolution; hydrogen metabolism; nitrogenase; hydrogenase; hydrogen; uptake hydrogenase; hupSL; hydrogen uptake mutant; uptake hydrogenase mutant; photobioreactor; hydrogenase accessory genes; hyp; transcription; RT-PCR; NtcA; mass spectrometry; heterocyst; Mikrobiologi; Microbiology; immunology; infectious diseases; Mikrobiologi; immunologi; infektionssjukdomar;

    Sammanfattning : Molecular hydrogen is a potential energy carrier for the future. Nitrogen-fixing cyanobacteria are a group of photosynthetic microorganisms with the inherent ability to produce molecular hydrogen via the enzyme complex nitrogenase. This hydrogen is not released, however, but is recaptured by the bacteria using an uptake hydrogenase. LÄS MER

  7. 5. Epiphytic lichen responses to nitrogen deposition

    Författare :Otilia Johansson; Kristin Palmqvist; Johan Olofsson; Annika Nordin; Lars E Ericson; Peter Crittenden; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Lichens; air pollution; nitrogen deposition; phosphorus; growth; chlorophyll a; boreal forest; field experiment; irrigation; carbon based secondary compounds; Lavar; luftföroreningar; alg; svamp; kväve; fosfor; skog; Terrestrial ecology; Terrestrisk ekologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : Nitrogen (N) deposition has increased globally over the last 150 years and further increase is predicted for the future. Nitrogen is an important nutrient for lichens, involved in many processes in both photobiont and mycobiont.  However, N can be a stressor, causing many lichens and lichen communities to disappear with increased deposition. LÄS MER