Sökning: "Pollen interactions"
Visar resultat 1 - 5 av 20 avhandlingar innehållade orden Pollen interactions.
1. Pollen Competition as a Target for Sexual Selection in Plants
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
2. Plant-animal interactions and seed output of two insectpollinated herbs
Sammanfattning : I combined comparative and experimental studies in the field and in the greenhouse to examine factors influencing reproductive success in two insect-pollinated herbs, the tristylous, selfincompatible perennial Lythrum salicaria and the self-compatible, biennial Pedicularis palustris. More specifically, I explored (i) the effects of plant population characteristics on the intensity and outcome of interactions with pollinators and seed predators, (ii) whether flower morphology affects duration of stigma receptivity, and (iii) whether damage-induced reduction in floral display reduces pollinator visitation and increases pollen limitation. LÄS MER
3. The Earth : climate and anthropogenic interactions in a long time perspective
Sammanfattning : The Earth is a highly complex and dynamic system. Life has shaped the entire planet and evolved in response to living conditions. Ecosystems are heavily affected by climate. Rapidly changing conditions imply considerable stress on several species and ecosystems, as well as to the most dominant species on the planet. LÄS MER
4. Plant-climate interactions over historical and geological time
Sammanfattning : Data-model comparisons are a useful approach to elucidating the relative influence of past climate change on vegetation dynamics over various spatial global, regional, stand) and temporal (historical, geological) scales. Comparisons between changes in tree species abundance reconstructed from pollen and simulated from a forest gap model, for example, indicate that based solely on climate change over the past 1500 years, southern Scandinavian forests should be co-dominated by Tilia and Fagus. LÄS MER
5. Selection on floral traits in Primula farinosa
Sammanfattning : Flowers and inflorescences have evolved in relation to animals for at least 100 million years. Plants attract pollinators with large, conspicuous, bright-coloured or scented flowers. These display attributes, however, also attract herbivores. LÄS MER
