Sökning: "seed-set"

Visar resultat 1 - 5 av 17 avhandlingar innehållade ordet seed-set.

  1. 1. Reproductive patterns of birches (Betula spp.) in northern Sweden

    Författare :Stig-Olov Holm; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Reproduction; Betula; seed-quality; seed-set; pollination; pollen-limitation; pollen-competition; tree-line; environmental gradient; seed weight; seedling survival; Semudobia;

    Sammanfattning : The aim of this thesis was to study patterns of reproduction of Betula pendula and B. pubescens coll. along an altitudinal, coastal-inland, gradient in northern Sweden. The altitudinal variation was related to the distribution of the birch taxa along the gradient. LÄS MER

  3. 2. The spatial and temporal dynamics of plant-animal interactions in the forest herb Actaea spicata

    Författare :Hugo von Zeipel; Johan Ehrlén; Ove Eriksson; Saskya van Nouhuys; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Eupithecia immundata; parasitoid; rodent; seed predation; dispersal; recruitment; multitrophic; metapopulation; trophic cascades; community complexity; Biology; Biologi; Plant Ecology; växtekologi;

    Sammanfattning : Landscape effects on species performance currently receives much attention. Habitat loss and fragmentation are considered major threats to species diversity. Deciduous forests in southern Sweden are previous wooded pastures that have become species-rich communities appearing as islands in agricultural landscapes, varying in species composition. LÄS MER

  4. 3. Sexual conflict and selection on pistil and pollen traits

    Författare :Josefin Madjidian; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Antagonistic trait; Collinsia heterophylla; delayed stigma receptivity; direct cost; first-donor advantage; gender bias; heritability; indirect benefit; mate choice; mixed-mating system; paternal diversity; pollen competition; pollen deposition; pollen load size; pollen tube growth rate; self-compatibility; semantics; sexual conflict; sexual selection; sexually antagonistic co-evolution;

    Sammanfattning : The incidence of sexual selection in plants is today acknowledged, however, just as in animals, evolution and maintenance of mate choice is gravely underexplored. Moreover, the potential for sexual conflicts to occur in plants has only been assessed empirically to a very limited degree. LÄS MER

  5. 4. Ecology of pollinators, pests and natural enemies in agricultural landscapes : ensuring a sustainable supply of clover seeds

    Författare :Veronica Hederström; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The human population and its food consumption continues to grow and the environmental impact of meeting future food demands depends on how we expand the food supply. Already, agricultural intensification has led to biodiversity declines, which in turn can have direct and indirect effects on agricultural production. LÄS MER

  7. 5. Life History Strategies in Linnaea borealis

    Författare :Mikael Niva; Brita M. Svensson; P. Staffan Karlsson; Ørjan Totland; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biology; Linnaea borealis; apex removal; apical dominance; clonal plant; hand pollination; matrix modelling; plant foraging; resorption efficiency; resorption proficiency; resource heterogeneity; shoot dynamics; Biologi; Biology; Biologi; ekologisk botanik; Ecological Botany;

    Sammanfattning : About 70% of the plant species in the temperate zone are characterised by clonal growth, clonal species are also in majority in the Arctic and Subarctic where they affect the structure and composition of the vegetation. It is therefore of great importance to increase our knowledge about clonal plants and their growth and life histories. LÄS MER