Sökning: "pollen-competition"

Visar resultat 1 - 5 av 7 avhandlingar innehållade ordet pollen-competition.

1. 1. Pollen Competition as a Target for Sexual Selection in Plants

   Författare :Åsa Lankinen; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sexual selection; Pollen tube growth rate; Pollen selection models; Pollen interactions; Pollen competition; Plants; Phenotypic plasticity; Non-random mating; Genotype by environment interactions; Mate choice; Viola tricolor.; Plant ecology; Växtekologi;

   Sammanfattning : According to the theory of sexual selection, traits can evolve because they confer a mating advantage in competition with members from the same sex. In animals, sexual selection is considered as an important evolutionary force. In this thesis I have investigated the potential for sexual selection in plants. LÄS MER

3. 2. Male and female selective mechanisms, reproductive success and gene flow

   Författare :Samuel Kiboi; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Växtekologi; Plant ecology; Cucumis sativus.; genetic marker; gene flow; reproduction; embryo abortion; resistance; maternal selection; sexual selection; pollen competition; selection;

   Sammanfattning : In this thesis, I have studied male and female selective mechanisms that can affect plant reproductive success and gene flow. I have focussed on sexually selected traits, mainly pollen competition and maternal sorting mechanisms, for example through non-random ovule abortion. 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. 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

7. 5. Pollination processes - maternal and offspring performance

   Författare :Kristina Holmén Bränn; Kari Lehtilä; Pia Mutikainen; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Pollination; Sinapis arvensis; Brassica napus; Raphanus raphanistrum; Succisa pratensis; Evolution of flower size; Maternal plant responses; Resource allocation; Reproductive success; Terrestrial ecology; Terrestisk ekologi; Plant Ecology; växtekologi;

   Sammanfattning : Pollination is one of the most important factors determining the reproductive success of plants. This thesis examines processes associated to varying pollination, with focus on plant responses. The first aim was to examine the possibility and constraints for short-term evolution of flower size in Raphanus raphanistrum. LÄS MER