In order to combat the growing problems associated with biological invasions, many researchers have focused on identifying which communities are most vulnerable to invasion by exotic species. However, once established, invasive species can significantly change the composition of the communities that they invade. The first step to disentangling the direction of causality is to discern whether a ...

In a 2-year field study, we quantified lateral root growth patterns and soil water depletion dynamics in the invasive annual Centaurea solstitialis and two native perennials, Elymus glaucus and Grindelia camporum. Centaurea solstitialis produced lateral roots most actively from early April to mid-June, during the late rosette to spiny seedhead stage while both root growth and water depletion we...

BACKGROUND Centaurea aegyptiaca L (Asteraceae), is one of the most attractive plants growing wildly in Sinai, and is not well investigated for its phytochemical constituents. This study represents the first in-depth characterization of the phenolic profile of the aerial parts of C. aegyptiaca methanolic extract utilizing liquid chromatography (LC) combined with electrospray ionization (ESI) tan...

The blue bottle experiment is a collective term for autoxidation reactions catalysed by redox indicators. The reactions are characterized by their repeatable cycle of colour changes when shaken/left to stand and intricate chemical pattern formation. The blue bottle experiment is studied based on calculated solution-phase half-cell reduction potential of related reactions. Our investigation conf...

The effects of declining plant biodiversity on ecosystem processes are well studied, with most investigations examining the role of species richness declines rather than declines of species abundance. Using grassland mesocosms, we examined how the abundance of a native, resident species, Hemizonia congesta (hayfield tarweed), affected exotic Centaurea solstitialis (yellow starthistle) invasion....

Understanding the role of competition in the organization of communities is limited in part by the difficulty of extrapolating the outcomes of small-scale experiments to how such outcomes might affect the distribution and abundance of species. We modeled the community-level outcomes of competition, using experimentally derived competitive effects and responses between an exotic invasive plant, ...

Our understanding of the potential mechanisms driving the spread and naturalization of alien plant species has increased over the past decades, but specific knowledge on the factors contributing to their increased impact in the introduced range is still urgently needed. The native European plant Centaurea stoebe occurs as two cytotypes with different life histories (monocarpic diploids, allo-po...

The species of Asteraceae have been found to be a rich source of externally accumulated flavonoid aglycones. This type of compounds attracts the attention, besides for their importance as chemotaxonomic markers, also for their ecological role. In the present study, two local endemic species, Centaurea davidovii and C. parilica, and one widespread species from the same group, C. stenolepis, are ...