Sökning: "leaf size"

Visar resultat 11 - 15 av 40 avhandlingar innehållade orden leaf size.

  1. 11. Linking plant population dynamics to the local environment and forest succession

    Författare :Johan Petter Dahlgren; Johan Ehrlén; Ove Eriksson; Mark Rees; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Actaea spicata; Forest herbs; Forest succession; Integral projection model; Plant demography; Plant phenology; Population dynamics; Pre-dispersal seed predation; Seed mass; Soil potassium; Specific leaf area; Terrestrial ecology; Terrestisk ekologi; Plant Ecology; växtekologi;

    Sammanfattning : Linking environmental variation to population dynamics is necessary to understand and predict how the environment influences species abundances and distributions. I used demographic, environmental and trait data of forest herbs to study effects of spatial variation in environmental factors on populations as well as environmental change in terms of effects of forest succession on field layer plants. LÄS MER

  3. 12. Life History and Tolerance and Resistance against Herbivores in Natural Populations of Arabidopsis thaliana

    Författare :Reiko Akiyama; Jon Ågren; Arjen Biere; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Arabidopsis thaliana; life history evolution; flowering time; germination; phenology; plant-herbivore interactions; natural selection; tolerance to leaf damage; resistance to herbivory; Plutella xylostella; Mamestra brassicae; Biology with specialization in Ecological Botany; Biologi med inriktning mot ekologisk botanik;

    Sammanfattning : In this thesis, I combined observational studies with field and greenhouse experiments to examine selection on life history traits and variation in tolerance and resistance against herbivores in natural populations of the annual herb Arabidopsis thaliana in its native range. I investigated (1) phenotypic selection on flowering time and plant size, (2) the effects of timing of germination on plant fitness, (3) the effect of leaf damage on seed production, and (4) correlations between resistance against a specialist and a generalist insect herbivore. LÄS MER

  4. 13. Molecular epidemiology of begomoviruses that infect vegetable crops in southwestern Cameroon

    Författare :Walter Nkeabeng Leke; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Begomoviruses are plant-infecting viruses, which are transmitted by the whitefly vector Bemisia tabaci. They have a genome of single-stranded DNA that consists of either a single (monopartite) or two components (bipartite) with a component size of approximately 2.8 kb. LÄS MER

  5. 14. What do snails do in ecosystems? it is a matter of traits

    Författare :Tina Astor; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Current environmental changes demand the ability to predict possible consequences for ecosystems performing important functions regulating the Earth system, and providing essential services for human well-being. Indirect impacts can occur through changes in biotic communities. LÄS MER

  7. 15. Behavioural mechanisms behind aggregation in a tritrophic perspective

    Författare :Jörg Stephan; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES;

    Sammanfattning : Gregarious organisms need to handle the trade-off between positive effects of group living and increasing food competition. The gregarious Phratora vulgatissima, a specialist leaf beetle on willow in Europe and Asia, frequently reaches outbreak densities in natural stands and short rotation coppices. LÄS MER