Sökning: "transplant experiment"

Visar resultat 1 - 5 av 14 avhandlingar innehållade orden transplant experiment.

  1. 1. Effects of climate change on boreal wetland and riparian vegetation

    Författare :Lotta Ström; Roland Jansson; Christer Nilsson; Sarah Gergel; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; biomass; flooding; hydrologic niche; invasibility; riparian zone; riparian plant species; river margin; climate scenario; seed sowing experiment; species composition; species richness; transplant experiment; Terrestrial ecology; Terrestrisk ekologi;

    Sammanfattning : Models of climate change predict that temperature will increase during the 21th century and the largest warming will take place at high northern latitudes. In addition to warming, predictions for northern Europe include increased annual precipitation and a higher proportion of the precipitation during winter falling as rain instead of snow. LÄS MER

  2. 2. Pollinator-mediated selection and the evolution of floral traits in orchids

    Författare :Judith Trunschke; Jon Ågren; Nina Sletvold; Allan G. Ellis; Uppsala universitet; []
    Nyckelord :Among-population variation; Ecotype; Field experiment; Floral evolution; Germination; Local adaptation; Orchidaceae; Platanthera bifolia; Phenotypic selection; Pollination; Reciprocal transplant; Trait manipulation; Biology with specialization in Ecological Botany; Biologi med inriktning mot ekologisk botanik;

    Sammanfattning : In this thesis, I combined manipulations of traits and pollination environment with analysis of phenotypic selection to examine causes of variation in strength and mode of selection on floral traits, and I conducted a reciprocal sowing experiment to test for local adaptation in germination success. I tested the following predictions (1) the opportunity for selection, and the strength of pollinator-mediated and net selection increase with increasing pollen limitation, (2) the effects of traits affecting pollinator attraction and traits affecting pollination efficiency are non-additive and this leads to pollinator-mediated correlational selection, (3) the effects of spur length on pollen removal, pollen receipt, and female fitness differ between populations with short-tongued and populations with long-tongued pollinators, and (4) local adaptation at the stage of germination contributes to the maintenance of ecotypes growing in grasslands and woodlands, respectively. LÄS MER

  3. 3. Survival of Cultured and Grafted Embryonic Dopaminergic Neurones - Effects of hypothermia and prevention of oxidative stress

    Författare :Jenny Karlsson; Neurobiologi; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Neurology; 6-OHDA; lazaroid; PBN; brain; transplant; Parkinson s disease; dopamine; neuropsychology; neurophysiology; Neurologi; neuropsykologi; neurofysiologi;

    Sammanfattning : Transplantation of embryonic dopaminergic neurones can ameliorate symptoms in Parkinson’s disease, but a major obstacle for clinical transplantations to overcome is the low survival (typically 5-10%) of implanted nigral neurones. If cell death in nigral grafts can be prevented, less embryonic tissue would be needed per transplantation session and hence more patients could receive intracerebral grafts as a therapy for Parkinson’s disease. LÄS MER

  4. 4. Plant-Animal Interactions and Evolution of Floral Display and Flowering Phenology in Arabidopsis lyrata

    Författare :Saskia Sandring; Jon Ågren; Johan Ehrlén; José Gómez; Uppsala universitet; []
    Nyckelord :Ecology; Arabidopsis lyrata; natural selection; floral display; phenology; flowering time; plant-animal interactions; pollination; herbivory; selection gradients; population differentiation; local adaptation; Ekologi;

    Sammanfattning : In this thesis, I combined comparative and experimental approaches to examine selection on reproductive traits, and population differentiation in the insect-pollinated, outcrossing, perennial herb Arabidopsis lyrata. More specifically, I (1) determined whether selection on flowering phenology and floral display can be attributed to interactions with pollinators and herbivores, (2) examined whether population differentiation in flowering phenology and floral display is correlated with current selection on these traits, and (3) tested for local adaptation from contrasting environments in Europe. LÄS MER

  5. 5. Ecological and Evolutionary Consequences of Herbivory in the Perennial Herb Lythrum salicaria

    Författare :Lina Lehndal; Jon Ågren; Peter Hambäck; Marc Johnson; Uppsala universitet; []
    Nyckelord :Disturbance gradient; Female reproductive success; Galerucella calmariensis; Galerucella pusilla; Herbivore removal; Latitudinal gradient; Local adaptation; Nanophyes marmoratus; Plant-herbivore interactions; Plant size; Resistance to herbivory; Tolerance to damage; Biology with specialization in Ecological Botany; Biologi med inriktning mot ekologisk botanik;

    Sammanfattning : In this thesis, I combined field, common-garden and greenhouse experiments to examine the ecological and evolutionary consequences of plant-herbivore interactions in the perennial herb Lythrum salicaria. More specifically I examined (1) whether resistance and tolerance to damage from herbivores vary with latitude and are positively related to the intensity of herbivory in natural populations, (2) whether effects of herbivory on plant fitness vary with latitude, (3) whether populations are locally adapted and whether herbivory influences the relative fitness of populations, and (4) whether the intensity and effects of insect herbivory on reproductive output vary locally along a disturbance gradient and are associated with differences in plant resistance. LÄS MER