Sökning: "b-radiation"

Visar resultat 1 - 5 av 18 avhandlingar innehållade ordet b-radiation.

  1. 1. Evolutionary ecology of ultraviolet-B radiation stress tolerance in amphibians

    Författare :Maarit Pahkala; Trevor Beebee; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Developmental biology; amphibians; anomalies; embryonic development; geographic variation; growth; Rana arvalis; Rana temporaria; survival; UV-B radiation; Utvecklingsbiologi; Developmental biology; Utvecklingsbiologi; populationsbiologi; Population Biology;

    Sammanfattning : During the last decades many amphibian species and populations have experienced declines and extinctions in different parts of the world. Anthropogenic activities are believed to account for these declines, and one of the hypothesized causes has been the increased level of ultraviolet-B (UV-B) radiation due to depletion of the stratospheric ozone layer. LÄS MER

  3. 2. Effects of enhanced ultraviolet-B radiation on subarctic ecosystems

    Författare :Carola Gehrke; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; pigmentation; photosynthesis; dark respiration; shoot morphology; shoot growth; phanerogams ; species composition cryptogams; productivity; decomposition; dwarf shrubs; bryophytes; peatland ecosystem; heath ecosystem; UV-B; ozone depletion; Plant ecology; Växtekologi;

    Sammanfattning : Biologically harmful ultraviolet-B radiation (UV-B, 280-320 nm) is increasing at the Earth´s surface owing to stratospheric ozone depletion. This is of global concern due to potential impacts of enhanced UV-B radiation on the biosphere. LÄS MER

  4. 3. The surface complex of Euglena gracilis. Involvement in cellular movements and biochemical and molecular analyses of the components

    Författare :Silja K Petersen-Mahrt; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; UV-B radiation; tubulin; surface complex; plasma membrane; phylogeny; phototaxis; nitrogen deficiency; membrane skeleton; Euglena gracilis; actin; cell shape; Physiological biophysics; Växtfysiologi;

    Sammanfattning : The flagellate Euglena gracilis shows rhythms in phototaxis and cell shape changes between oblong and round. Artificial UV-B radiation of 0.5 W m-2 caused a loss in phototaxis, but the peak of activity occurred at the same time as for control cells. LÄS MER

  5. 4. Biological Weighting of UV-B Radiation. The importance of wavelength for the inhibition of microalgae

    Författare :Kristin I. M. Andreasson; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : .... LÄS MER

  7. 5. Modification of flavonoid content and photosynthesis by ultraviolet-B radiation. Atrazine-tolerant and -sensitive ultivars of Brassica napus

    Författare :Louise Olsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; recovery; quercetin; photosynthesis; photoinhibition; photoacoustics; leaf anatomy; kaempferol; flavonoid; D1 protein; fluorescence; cold stress; carbon dioxide; atrazine tolerance; Brassica napus; UV-B; Physiological biophysics; Växtfysiologi;

    Sammanfattning : Levels of ultraviolet-B (UV-B, 280-320 nm) radiation reaching the Earth´s surface increase due to stratospheric ozone depletion. In this thesis the effect of enhanced UV-B radiation was studied on the atrazine-tolerant mutant Stallion, susceptible to photoinhibition, and the atrazine-sensitive cultivar Paroll of Brassica napus (oilseed rape). LÄS MER