Sökning: "asexual"

Visar resultat 1 - 5 av 50 avhandlingar innehållade ordet asexual.

  1. 1. Asexual embryogenesis in plants

    Författare :Boel Mårtensson; Biologiska institutionen; []
    Nyckelord :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 .;

    Sammanfattning : 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. LÄS MER

  3. 2. Metapopulation and metacommunity processes, dispersal strategies and life-history trade-offs in epiphytes

    Författare :Swantje Löbel; Håkan Rydin; Tord Snäll; Lars E. Ericson; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; asexual; biodiversity; bryophytes; dispersal limitation; establishment; evolution of reproductive traits; germination; growth; habitat fragmentation; landscape dynamics; local processes; patch-tracking; pH; reproduction; species richness; species interactions; Other biology; Övrig biologi; Ecological Botany; Ekologisk botanik;

    Sammanfattning : The aim of this thesis was to increase knowledge about metapopulation and metacommunity processes in patchy, dynamic landscapes, using epiphytic bryophytes as a model system. Host trees and deciduous forest stands in the coniferous landscape are patchy, temporal and undergo changes in habitat quality during succession. LÄS MER

  4. 3. Surviving the ratchet : Modelling deleterious mutations in asexual populations

    Författare :Jonas Söderberg; Otto Berg; Laurence Loewe; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Theoretical biology; Population genetics; Stochastic modelling; Genome evolution; Muller s Ratchet; Genetics; Genetik; Organism biology; Organismbiologi; Biology; Biologi; Biologi med inriktning mot molekylär evolution; Biology with specialization in Molecular Evolution;

    Sammanfattning : One of the most unforgiving processes in nature is that of Muller's ratchet, a seemingly irreversible accumulation of deleterious mutations that all organisms have to deal with or face extinction. The most obvious way to avoid fitness collapse is recombination, though asexual populations usually do not have the luxury of recombining freely. LÄS MER

  5. 4. Studies on Plasmodium falciparum asexual blood stage antigens : RAP-2/RSP-2 and Pf332 in focus

    Författare :Nancy Awah; Klavs Berzins; Marcel Hommel; Stockholms universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; immunity; malaria; RBCs; anaemia; Immunology; Immunologi; immunologi; Immunology;

    Sammanfattning : The life cycle of the malaria parasite is very complex and provides a number of potential targets for vaccination. In this thesis, data on two plasmodial asexual blood stage antigens (RAP-2 and Pf332) are presented. LÄS MER

  7. 5. On enchytraeids and naidids: Life history traits and responses to environmental stress

    Författare :Anna-Karin Augustsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; oligochaeta; terrestrial naididae; toxicity testing; asexual reproduction; sexual reproduction; drought; environmental stress; metal pollution; Ekologi; Animal ecology; Djurekologi;

    Sammanfattning : My thesis shows that enchytraeids and naidids are sensitive to various forms of environmental stress, which in combination with the wide distribution of both families make them highly suitable for use in risk assessment and soil monitoring. Enchytraeids were subject to chemical stress under both laboratory and field conditions. LÄS MER