Floral Signaling Variation in Self-compatible and Self-incompatible populations of Arabidopsis lyrata
Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
Transition from outcrossing to self-fertilization is a common phenomenon in angiosperm mating systems across evolutionary lineages. This transition is often accompanied by quantitative changes in floral traits required for the attraction of pollinators. The changes, described as the selfing syndrome, often include reduced floral size, reduced nectar and scent production, reduced pollen to ovule ratio and reduced herkogamy. I compared several of these traits in different populations of the perennial herb Arabidopsis lyrata from Europe (Sweden) and North America (The Great Lakes area). Whereas most populations are self-incompatible, and thus obligate outcrossers, some North American populations of A. lyrata, have evolved self-compatibility. Inmy work, I analysed the variation and covariation of visual and chemical floral signals within and among selfing and outcrossing population at both small and large geographical scales. In a greenhouse common garden, I compared the floral morphology, floral scent and mating system of four populations from Sweden and seven populations from the Great Lakes area. Variation in floral signals among populations was largely explained by the geographical location not by mating system. No reproductive physiology differences (herkogamy) was observed between selfcompatible and self-incompatible populations of the Great Lakes. Variation in floral signals between self-compatible and self-incompatible populations was very small with only one selfcompatible population showing signs of selfing syndrome both in terms of visual and chemical signals. The results further revealed a negative correlation between floral scent and flower size across the continental scale, whereas the same traits were positively correlated in the subsample of North American populations. This result implies that there is no general constraints on the evolution of visual and chemical signals and that variations at population level could be due to local selection at the population scale.
Place, publisher, year, edition, pages
2015. , 27 p.
Arabidopsis lyrata, floral signals, selfing syndrome, floral scent
IdentifiersURN: urn:nbn:se:uu:diva-276460OAI: oai:DiVA.org:uu-276460DiVA: diva2:903085
Master Programme in Biology
Friberg, Magne, Dr.