Arabidopsis thaliana: a new test species for phytotoxic bioassays.

Lettuce seeds (Lactuca sativa L.) and other crop species are often used in phytotoxic bioassays that are designed to detect allelochemicals. The seeds of these species are considered ideal because they are readily available, germinate rapidly and uniformly, and are routinely used in laboratories around the world.

Interesting biological activities from plants traditionally used by Native Australians.

Four plants routinely used for medicinal purposes by Native Australians were screened for various biological activities. Methanol extracts of Eremophila maculata, Acacia auriculoformis and Acacia bivenosa exhibited antibiotic effects, while Eremophila alternifolia yielded an extract that induced significant changes to the heart activity of spontaneously hypertensive rats. We report on these biological activities.

Inferring process from pattern in plant invasions: a semimechanistic model incorporating propagule pressure and environmental factors.

Propagule pressure is intuitively a key factor in biological invasions: increased availability of propagules increases the chances of establishment, persistence, naturalization, and invasion. The role of propagule pressure relative to disturbance and various environmental factors is, however, difficult to quantify. We explored the relative importance of factors driving invasions using detailed data on the distribution and percentage cover of alien tree species on South Africa's Agulhas Plain (2,160 km2).

Integrating biosystematic data into conservation planning: perspectives from southern Africa's Succulent Karoo.

In this paper we explore the role that biosystematists can play in conservation planning. Conservation planning concerns the location and design of reserves that both represent the biodiversity of a region and enable the persistence of that biodiversity by maintaining key ecological and evolutionary processes. For conservation planning to be effective, quantitative targets are needed for the spatial components of a region that reflect evolutionary processes.

Plant diversity in mediterranean-climate regions.

The high plant diversity of mediterranean-climate regions has attracted much attention over the past few years. This review discusses patterns and determinants of local, differential and regional plant diversity in all five regions. Local diversity shows great variation within and between regions and explanations for these patterns invoke a wide range of hypotheses.

Smoke-induced germination of succulents (Mesembryanthemaceae) from fire-prone and fire-free habitats in South Africa.

Previous studies have shown germination to be stimulated by fire-related cues such as heat and charate extract and, more recently, plant-derived smoke extract. However, smoke extract has not been tested on non-fire-prone species. We hypothesized that smoke-induced germination would be restricted to fire-prone species and investigated responses of members of the family Mesembryanthemaceae which has genera confined to fire-prone and to non-fire-prone habitats as well as genera with species across both habitats.

Winter growth phenology and leaf orientation in Pachypodium namaquanum (Apocynaceae) in the succulent karoo of the Richtersveld, South Africa.

Pachypodium namaquanum (Nyley ex Harb.) Welw., an unusual arborescent stem succulent from the succulent karoo of the arid Richtersveld in north-western South Africa and adjacent Namibia, is characterized by a striking curvature of the terminal 20-60 cm of the trunk toward the north.