Sökning: "Germination timing"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden Germination timing.

1. 1. Seed dormancy and germination in an ecological context : comparative studies of annual weeds

   Författare :Laila Karlsson; Per Milberg; Ken Thompson; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Asteraceae; Bidens; Compositae; deadnettle; Galinsoga; germination timing; Guizotia; evolution; Labiatae; Lamiaceae; Lamium; morphophysiological dormancy; Papaveraceae; Papaver; Parthenium; physiological dormancy; poppy; summer annual; Tagetes; Verbesina; winter annual; Biology; Biologi;

   Sammanfattning : Germination ecology studies, i.e. studies of interactions between characteristics of the seeds and environmental circumstances, provide understanding of spatial and temporal patterns of emergence of wild species, as weeds in the field. A large number of species have seed dormancy, i. LÄS MER

3. 2. Selection during Early Life Stages and Local Adaptation in Arabidopsis thaliana

   Författare :Froukje M. Postma; Jon Ågren; Kathleen Donohue; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Dormancy cycling; Germination timing; Maternal effects; Natural variation; QTL mapping; Seed bank; Seed dormancy; Structural Equation Modeling; Biology with specialization in Ecological Botany; Biologi med inriktning mot ekologisk botanik;

   Sammanfattning : Organisms are often adapted to their local environment, but the role of early life stages in adaptive differentiation among populations remains poorly known. The aim of my thesis was to investigate the contribution of early life stages to the magnitude and genetic basis of local adaptation, and to identify the underlying adaptive traits. LÄS MER

4. 3. Life History and Tolerance and Resistance against Herbivores in Natural Populations of Arabidopsis thaliana

   Författare :Reiko Akiyama; Jon Ågren; Arjen Biere; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Arabidopsis thaliana; life history evolution; flowering time; germination; phenology; plant-herbivore interactions; natural selection; tolerance to leaf damage; resistance to herbivory; Plutella xylostella; Mamestra brassicae; Biology with specialization in Ecological Botany; Biologi med inriktning mot ekologisk botanik;

   Sammanfattning : In this thesis, I combined observational studies with field and greenhouse experiments to examine selection on life history traits and variation in tolerance and resistance against herbivores in natural populations of the annual herb Arabidopsis thaliana in its native range. I investigated (1) phenotypic selection on flowering time and plant size, (2) the effects of timing of germination on plant fitness, (3) the effect of leaf damage on seed production, and (4) correlations between resistance against a specialist and a generalist insect herbivore. LÄS MER

5. 4. Adaptation and Constraint in the Plant Reproductive Phase

   Författare :Kjell Bolmgren; Ove Eriksson; Bengt Oxelman; Jeff Ollerton; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; phenology; fleshy fruits; phylogenetic comparative methods; phylogenetic constraints; Rhamnus; Frangula; Frangula alnus; key innovations; allometry; diversity; phylogeny; seed size; frugivory; germination; recruitment; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

   Sammanfattning : Conservatism is a central theme of organismic evolution. Related species share characteristics due to their common ancestry. Some concern have been raised among evolutionary biologists, whether such conservatism is an expression of natural selection or of a constrained ability to adapt. LÄS MER

7. 5. Ecology and evolution of local adaptation in Arabidopsis thaliana

   Författare :Giulia Zacchello; Jon Ågren; Xavier Picó; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Arabidopsis thaliana; germination time; natural populations; Near isogenic lines; reciprocal transplants; seed bank; seed dormancy; Biology with specialization in Ecological Botany; Biologi med inriktning mot ekologisk botanik;

   Sammanfattning : In this thesis, I investigate the ecological genetics of local adaptation in the annual herb Arabidopsis thaliana with the aim to identify key traits, agents of selection, and genomic regions contributing to adaptive differentiation. The thesis focuses on adaptive differentiation in timing of germination and seed dormancy between populations located close to the southern and northern range margins in Europe. LÄS MER