Search for dissertations about: "pollen morphology"

Showing result 1 - 5 of 22 swedish dissertations containing the words pollen morphology.

  2. 1. Studies in Montia L., Claytonia L. and allied genera : Taxonomy, morphology, pollen morphology, cytology, reproduction and distribution

    Author : Örjan Nilsson; Uppsala universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP;

    Abstract : .... READ MORE

  4. 2. Pollen and pollination in Ephedra (Gnetales)

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

    Abstract : 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. READ MORE

  5. 3. Asexual embryogenesis in plants

    Author : Boel Mårtensson; Biologiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Systematic botany; two-phase partitioning; somatic embryogenesis; pollen embryogenesis; plasma membrane; peroxidase; Daucus carota isoperoxidase; Nicotiana tabacum; Ca2 transport; cell shape; calmodulin; taxonomy; morphology; phytogeography; chemotaxonomy. Physiology of nonvascular plants; Systematisk botanik; taxonomi; morfologi; kemotaxonomi. Växters fysiologi inte kärlväxter .;

    Abstract : The capacity of somatic cells and pollen grains or microspores to undergo embryogenesis is an important property used in improvement and regeneration of plants. Furthermore, somatic embryogenesis as well as pollen embryogenesis show many similarities with zygotic embryogenesis and are, thus, good model systems. READ MORE

  6. 4. Clonal structure and reproductive biology in the gynodioecious herb Glechoma hederacea L. Lamiaceae

    Author : Marie Widén; Biologiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Systematisk botanik; chemotaxonomy. Physiology of nonvascular plants; phytogeography; morphology; taxonomy; Systematic botany; clonal structure; isoloci; disomic inheritance; genetic diversity; polyploidy; male sterility; sex expression; pollen limitation; sexual reproduction; gynodioecy; Glechoma hederacea; Lamiaceae; taxonomi; morfologi; kemotaxonomi. Växters fysiologi inte kärlväxter .;

    Abstract : Clonal structure and reproductive biology in the gynodioecious herb Glechoma hederacea L. Lamiaceae The frequencies of females, hermaphrodites and partially male-sterile (PMS) genets of Glechoma hederacea were estimated in natural populations in S Sweden. The frequency of females and PMS genets in natural populations varied from 0 to 100%. READ MORE

  7. 5. 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