This paper describes the recent expansion of the geographical distribution of Limnoperna fortunei (Dunker, 1857) in the Tietê River watershed, São Paulo State, Brazil. Estimations related to the velocity of invasion and its causes are presented. Ecological implications related to biodiversity and possible changes in the food chain are discussed.

Title of Document: POLLINATOR SPECIALIZATION AND THE EVOLUTION OF POLLINATION SYNDROMES IN THE RELATED SILENE, S. CAROLINIANA, S. VIRGINICA, AND S. STELLATA Richard James Reynolds, Ph.D., 2008 Directed By: Associate Professor, Charles B. Fenster, Biology Associate Professor, Michele R. Dudash, Biology Pollination syndromes are the convergent expression of floral traits in unrelated species refl...

A small cluster of dioecious species in the plant genus Silene has evolved chromosomal sex determination and sex chromosomes relatively recently, within the last 10 million years (MY). Five dioecious Silene species (section Elisanthe) are very closely related (1-2 MY of divergence) and it was previously thought that all five have similar sex chromosomes. Here we demonstrate that in one of these...

BACKGROUND AND AIMS Among-population differentiation in phenotypic traits and allelic variation is expected as a consequence of isolation, drift, founder effects and local selection. Therefore, investigating molecular and quantitative genetic divergence is a pre-requisite for studies of local adaptation in response to selection under variable environmental conditions. METHODS Among- and withi...

The isovitexin-O-glycosylation patterns of rosette leaves, stem leaves and petals of Silene dioica plants were investigated. The 7-O -xylosylation o f isovitexin, controlled by gene gX, only occurs in the petals. In the leaves isovitexin is 7-O-galactosylated, which is controlled by gene Xgal. Acyl groups may be linked to either the 7 -0 or the 2"-0-substituted sugar; the former only occurs in ...