Sökning: "seed sowing"
Visar resultat 11 - 13 av 13 avhandlingar innehållade orden seed sowing.
11. Applications of visible and near infrared spectroscopy for sorting and identification of tree seeds
Sammanfattning : Seeds are the most commonly used regeneration material for reforestation purpose; hence interest in “precision sowing” among nurseries is high due to the high cost of containerized seedling production. In addition, the increased interest in growing hybrid larch in commercial forestry has raised concerns about the purity of hybrid larch seed lots, as there are large proportions of pure parental seeds mixed with hybrid larch seed lots. LÄS MER
12. Reforestation by direct seeding of beech and oak : influence of granivorous rodents and site preparation
Sammanfattning : In southern Scandinavia there is a general desire to increase the amount of broadleaved forest using, for example, beech and oak, in order to preserve biodiversity and spread risk in the face of climate change. In order to realise this goal cheaper regeneration methods are needed. LÄS MER
13. Pollinator-mediated selection and the evolution of floral traits in orchids
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