Sökning: "reproductive output"
Visar resultat 1 - 5 av 41 avhandlingar innehållade orden reproductive output.
1. Breeding System Evolution and Pollination Success in the Wind-Pollinated Herb Plantago maritima
Sammanfattning : In this thesis, I examined variation in sex expression and mating patterns in the sexually polymorphic, wind-pollinated herb Plantago maritima. With a combination of field studies, greenhouse experiments, and genetic analyses, I (a) examined factors influencing sex ratio variation in gynodioecious plants (in which hermaphrodites and females coexist), (b) discovered variation in breeding system, (c) investigated density-dependence of seed production, and (d) documented genetic variation within and among populations close to the northern range margin in Europe. LÄS MER
2. Fetal Cardiac Function and Venous Circulation - Experiences with Velocity Vector Imaging
Sammanfattning : Placental dysfunction resulting in intrauterine growth restriction (IUGR) is a common complication of pregnany and severe IUGR, with ensuing fetal hypoxia is an important cause of perinatal mortality and morbidity. Doppler studies of fetal and maternal vessels are routinely used for fetal surveillance and alterations in fetal venous blood flow has been demonstrated as a late sign of fetal compromise. LÄS MER
3. Intraovarian mechanisms influencing the human corpus luteum
Sammanfattning : Introduction: The human corpus luteum (CL) is a transient endocrine gland, only functionally active for about 14 days. Its principal function is to produce and secrete progesterone and thereby support the endometrium for implantation of a blastocyst and prevent rejection of the developing embryo. LÄS MER
4. Plant-animal interactions and seed output of two insectpollinated herbs
Sammanfattning : I combined comparative and experimental studies in the field and in the greenhouse to examine factors influencing reproductive success in two insect-pollinated herbs, the tristylous, selfincompatible perennial Lythrum salicaria and the self-compatible, biennial Pedicularis palustris. More specifically, I explored (i) the effects of plant population characteristics on the intensity and outcome of interactions with pollinators and seed predators, (ii) whether flower morphology affects duration of stigma receptivity, and (iii) whether damage-induced reduction in floral display reduces pollinator visitation and increases pollen limitation. LÄS MER
5. Coping with environmental change : Lessons from isotope studies in a sentinel species
Sammanfattning : Adaptive evolution and phenotypic plasticity are two key mechanisms by which natural populations avoid extinction in the face of environmental change. Evolutionary young systems, such as the Baltic Sea with low species diversity and steep environmental gradients, are good models for studying how wild populations cope with environmental changes, such as climate-induced alterations in food supply and exposure to environmental contaminants. LÄS MER