Back to Gondwanaland: can ancient vicariance explain (some) Indian Ocean disjunct plant distributions?

Oceans, or other wide expanses of inhospitable environment, interrupt present day distributions of many plant groups. Using molecular dating techniques, generally incorporating fossil evidence, we can estimate when such distributions originated. Numerous dating analyses have recently precipitated a paradigm shift in the general explanations for the phenomenon, away from older geological causes, such as continental drift, in favour of more recent, long-distance dispersal (LDD).

Novel microsatellite loci for Sebaea aurea (Gentianaceae) and cross-amplification in related species.

Premise Of The Study: Microsatellite loci were developed in Sebaea aurea (Gentianaceae) to investigate the functional role of diplostigmaty (i.e., the presence of additional stigmas along the style).

Diplostigmaty in plants: a novel mechanism that provides reproductive assurance.

Differentiation of female sexual organs in flowering plants is rare and contrasts with the wide range of male reproductive strategies. An unusual example involves diplostigmaty, the possession of spatially and temporally distinct stigmas in Sebaea (Gentianaceae). Here, the single pistil within a flower has an apical stigma, as occurs in most flowering plants, but also a secondary stigma that occurs midway down the style, which is physically discrete and receptive several days after the apical stigma.

Variation and evolution of herkogamy in Exochaenium (Gentianaceae): implications for the evolution of distyly.

Backgrounds And Aims: The spatial separation of stigmas and anthers (herkogamy) in flowering plants functions to reduce self-pollination and avoid interference between pollen dispersal and receipt. Little is known about the evolutionary relationships among the three main forms of herkogamy - approach, reverse and reciprocal herkogamy (distyly) - or about transitions to and from a non-herkogamous condition. This problem was examined in Exochaenium (Gentianaceae), a genus of African herbs that exhibits considerable variation in floral morphology, including the three forms of herkogamy.

Phylogenetic relationships of the mycoheterotrophic genus Voyria and the implications for the biogeographic history of Gentianaceae.

Premise Of The Study: The angiosperm family Gentianaceae comprises over 1700 species in 91 genera. Gentianaceae are distributed worldwide, but most species occur in temperate zones. Phylogenetic studies demonstrate that the family consists of six monophyletic tribes.

Ancestral and monophyletic presence of diplostigmaty in Sebaea (Gentianaceae) and its potential role as a morphological mixed mating strategy.

* Diplostigmaty, the presence of a primary (apical) stigma and secondary (mid-stylar) stigmas along the style, is only known from the genus Sebaea (Gentianaceae). Early work indicated that the secondary stigmas provide a mechanism of autogamy, suggesting that it might ensure reproductive assurance. * Here, we test the monophyly of this unique morphological trait.

The polyphyletic genus Sebaea (Gentianaceae): a step forward in understanding the morphological and karyological evolution of the Exaceae.

Within the Gentianaceae-Exaceae, the most species-rich genus Sebaea has received very little attention in terms of phylogenetic or karyological investigations. As a result, the exact number of species remains vague and the relationships with the other members of the Exaceae poorly understood. In this paper, we provide the first comprehensive phylogeny of the Exaceae including most Sebaea species known so far based on four cpDNA sequence regions.

Bio-guided isolation of cholinesterase inhibitors from the bulbs of Crinum x powellii.

In a search for potential acetylcholinesterase (AChE) inhibitors, the ethanol extract of the bulbs of Crinum x powellii (Amaryllidaceae) was found to demonstrate a marked inhibition of this enzyme. Using a bio-guided isolation strategy, linoleic acid ethyl ester has been identified as the compound responsible for this inhibition. Three other molecules - the alkaloid hippadine, the glycosylated benzyl alcohol derivative calleryanin and 4'-hydroxy-7-methoxyflavan - were also isolated and characterized for the first time from Crinum x powellii.