Sökning: "seed germination"

Visar resultat 11 - 15 av 43 avhandlingar innehållade orden seed germination.

1. 11. 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

3. 12. Studies on the Life Cycles of Akinete Forming Cyanobacteria

   Författare :Irene Karlsson Elfgren; Kurt Pettersson; Peter Blomqvist; Tore Lindholm; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biology; limnology; akinete; germination; recruitment; Biologi; Biology; Biologi; limnologi; Limnology;

   Sammanfattning : Cyanobacteria which can form resting cells (in this case akinetes) are common in meso-eutrophic lakes in temperate regions, often dominating the phytoplankton communities during summer. The life cycles of akinete-forming cyanobacteria has been studied with Gloeotrichia echinulata as a model organism. LÄS MER

4. 13. 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

5. 14. Studies on the regulation of the Napin napA promoter by ABI3, bZIP and bHLH transcription factors

   Författare :Nathalie Martin; Lars Rask; Ines Ezcurra; Olof Olsson; Uppsala universitet; []
   Nyckelord :Molecular biology; transcription gene regulation; plant seed maturation; seed storage protein; ABA; ABI3; bZIP; bHLH; Brassica napus; Molekylärbiologi;

   Sammanfattning : The B3-domain transcription factor ABI3 is a major regulator of gene expression of seed maturation during Arabidopsis embryogenesis. The napA gene encodes for a Brassica napus 2S storage protein specifically expressed in the embryo during the early and mid-maturation phase (MAT program). LÄS MER

7. 15. Seed dormancy and germination in Solanum nigrum and S. physalifolium as influenced by temperature conditions

   Författare :Alireza Taab; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
   Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES;

   Sammanfattning : .... LÄS MER