Sökning: "Pollination"

Visar resultat 1 - 5 av 67 avhandlingar innehållade ordet Pollination.

  1. 1. Pollen and pollination in Ephedra (Gnetales)

    Författare :Kristina Bolinder; Catarina Rydin; Johan Ehrlén; Michael S Zavada; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; aerodynamics; evolution; moonlight; pollination; pollen morphology; ultrastructure; växtsystematik; Plant Systematics;

    Sammanfattning : Ephedra (Gnetales) is a gymnosperm genus with a long evolutionary history; the first dispersed pollen grains with affinity to the group are known already from the Permian. This thesis focuses on the evolutionary history of the group and different aspects of its pollination mechanisms. LÄS MER

  2. 2. 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

  3. 3. Pollinators and Insect Pollination in Changing Agricultural Landscapes

    Författare :Lina Herbertsson; Miljövetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; pollinators; pollination; agri-environment schemes; beekeeping; oilseed rape; sown flower strips; agri-environment measures;

    Sammanfattning : Agricultural intensification and associated loss of semi-natural grasslands, has resulted in reduced landscape heterogeneity. A concomitant loss of forage and nest sites for pollinating insects has driven declines across several pollinator taxa. LÄS MER

  4. 4. The impact of forest on pest damage, pollinators and pollination services in an Ethiopian agricultural landscape

    Författare :Ulrika Samnegård; Kristoffer Hylander; Peter Hambäck; Sileshi Nemomissa; Jaboury Ghazoul; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; agroforestry; Apoidea; Coffea arabica; crop pests; Ethiopia; forest cover; landscape ecology; moist afromontane forests; pollination; species composition; tropical agriculture; Plant Ecology; växtekologi;

    Sammanfattning : The distribution of wild biodiversity in agroecosystems affect crop performance and yield in various ways. In this thesis I have studied the impact of wild biodiversity, in terms of trees and forest structures, on crop pests, pollinators and the pollination services provided in a heterogeneous landscape in southwestern Ethiopia. LÄS MER

  5. 5. Pollination in Ephedra (Gnetales)

    Författare :Kristina Bolinder; Catarina Rydin; Jürg Schönenberger; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; växtsystematik; Plant Systematics;

    Sammanfattning : Pollination, i.e., the transport of male gametophytes to female gametophytes, can occur with biotic or abiotic vectors and is necessary for fertilization and completion of the lifecycle in all seed plants. LÄS MER