Search for dissertations about: "pollen deposition"

Showing result 1 - 5 of 18 swedish dissertations containing the words pollen deposition.

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. 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

6. 4. Plant-animal interactions and seed output of two insectpollinated herbs

   Author : Anna R. Waites; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; plant reproduction; pollen limitation; pollinator behaviour; heterostyly; seed predation; Lythrum salicaria; Pedicularis palustris; stigma receptivity; self-pollen; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

   Abstract : 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. READ MORE

7. 5. Event stratigraphy for the Last Glacial-Holocene transition in eastern middle Sweden

   Author : Jonas Björck; Michael J.C Walker; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Last Glacial-Holocene transition; event stratigraphy; eastern middle Sweden; pollen; plant macrofossils; marine calcareous fossils; microtephra; radiocarbon dating; clay varve chronology; GRIP; ice-core chronology; calendar year chronology; Preboreal oscillation; Yoldia Sea; Baltic Ice Lake; Quaternary Geology; kvartärgeologi;

   Abstract : This thesis outlines an event stratigraphy for the Last Glacial-Holocene transition in eastern middle Sweden. Events are short-lived occurrences that have left traces in the geological record and which, therefore, may be used for correlation and inter-regional comparisons. READ MORE