Floral scent of willows (Salix spp.) and its role in reproduction

Weiden

From 04/2005 to 04/2008

Principal Investigator: Gregor Aas, Stefan Dötterl

Willows (Salix spp., Salicaceae) are a genus of woody dioecious plants with a high taxonomic and ecological diversity. From 300 to 500 different species are distinguished worldwide in the literature, about 40 species are known in Central Europe. A typical characteristic of most willow species is the possibility of hybridisation, but there lacks of knowledge about the limiting factors and the amount of this interspecific gene flow under natural conditions. Most of the Central European willows are flowering early in spring and are pollinated by insects. The aim of our investigations is the analysis of floral scents in the genus Salix. In particular we want to find an answer to the following questions: - Are there any specific patterns of floral scents in different willow species? - Are there any differences in male and female scent? - Do floral scents play a role in the specific attraction of insects and thus in preventing interspecific gene flow? The methods predominantly used in our investigations contain the chemical analysis of the floral scents with gas chromatography and mass spectrometry as well as the morphological determination of the pollinating insects. Furthermore the chemical components of pollen and nectar will be analysed.