Search for dissertations about: "pollen"

Showing result 1 - 5 of 237 swedish dissertations containing the word pollen.

  2. 1. Vegetation and climate during Weichselian ice free intervals in northern Sweden : Interpretations from fossil and modern pollen records

    Author : Martina Hättestrand; Ann-Marie Robertsson; Donatella Magri; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Weichselian; interstadial; stadial; glacial history; northern Sweden; Tärendö; Riipiharju; Rissejauratj; Veiki moraine; pollen analysis; pollen deposition; pollen trap; PAR; Quaternary geology; Kvartärgeologi;

    Abstract : In this thesis the Weichselian history of northern Sweden is investigated, with emphasis on vegetation and climate during ice-free intervals. The main method used has been pollen analysis of sediments from pre-Late Weichselian landforms. To interpret fossil pollen assemblages, comparisons with modern pollen spectra were made. READ MORE

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

    Author : Josefin Madjidian; Biologiska institutionen; []
    Keywords : 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;

    Abstract : 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. READ MORE

  5. 3. Pollen Competition as a Target for Sexual Selection in Plants

    Author : Åsa Lankinen; Biologiska institutionen; []
    Keywords : 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;

    Abstract : 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. READ MORE

  6. 4. Ultrastructure and ontogeny of some angiosperm pollen

    Author : Anita E. Dunbar; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Halvgräs; pollen; Säv; pollen; Klockväxter; pollen;

    Abstract : .... READ MORE

  7. 5. Estimating source area of pollen and pollen productivity in the cultural landscapes of southern Sweden - developing a palynological tool for quantifying past plant cover

    Author : Anna Broström; Kvartärgeologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; aerial photographs; pollen productivity estimates; relevant source area of pollen; southern Sweden; quantitative landscape reconstruction; GIS; pollen dispersal; simulation model; Geology; physical geography; Geologi; fysisk geografi;

    Abstract : Fossil pollen records retrieved from peat and lake sediments have great potential for quantifying past plant cover. This thesis is a contribution to the development of a palynological interpretation tool for reconstructing past cultural landscapes in terms of plant abundance and distribution. READ MORE