Character displacement drives floral variation in Pelargonium (Geraniaceae) communities.

Interactions between plant community members are an underexplored driver of angiosperm floral variation. We investigate character displacement as a potential contributor to floral variation in Pelargonium communities. Pelargoniums all place pollen on the ventral sides of their pollinators, potentially leading to interspecific pollen transfer (IPT) in sympatry. We show that the positions of pollen placement and receipt are determined by anther and style exsertion lengths. Using field experiments, we demonstrate that heterospecific species experience higher IPT if they have similar style lengths than when they have greater style length differences. Using crosses, we show that IPT has negative consequences on seed set. In combination, these results suggest that character displacement in style length is likely to reduce IPT and increase female fitness in sympatry. Patterns of style length variation across 29 different Pelargonium communities suggest that character displacement has occurred in multiple communities. Furthermore, analyses using a wide-ranging species pair show that style lengths are more different between sympatric populations than they are between allopatric populations. In addition to pollinators as agents of floral divergence, this study suggests that variation in Pelargonium community structure has driven style length variation through character displacement.

Reproduction of the Medicinal Plant Pelargonium sidoides via Somatic Embryogenesis.

The medicinal plant Pelargonium sidoides DC. (Geraniaceae) was traditionally used for the treatment of the common cold and cough in South Africa. Today an aequous-ethanolic root extract from this plant is approved for the treatment of acute bronchitis and is globally marketed also as an immunostimulant. The increasing demand of the plant material for the industrial production indicates the need of new effective methods for the propagation of P. sidoides. Here we report somatic embryogenesis and in vitro plantlet regeneration from somatic cells of inflorescence shoots and petioles of P. sidoides. A one-week cultivation of explants in media containing different concentrations of thidiazuron (1, 2.2, 3, and 4 mg/L) followed by a cultivation period without phytohormones resulted in the induction of somatic embryos within 2-4 weeks. After 2-4 months, the embryos generated roots and could be transferred into a greenhouse, where flower formation took place and the development of seeds occurred with high germination rates. The root umckalin concentration, determined by high-performance thin-layer chromatography, was comparable to that of seed-cultivated plants (100 ± 6 vs. 113 ± 10 µg umckalin/g dried roots). For the first time, direct somatic embryogenesis has been established as an appropriate cultivation method for P. sidoides plants used as raw material in the pharmaceutical industry. Moreover, genetically identical plants (chemical races) can be easily generated by this procedure.

Intercropping of aromatic crop Pelargonium graveolens with Solanum tuberosum for better productivity and soil health.

Farmers in hilly regions experience low production potential and resource use efficiency due to low valued crops and poorsoil health. Geranium (Pelargonium graveolens L.) is a vegetatively propagated initially slow growing, high value aromatic crop. Potato (Solanum tuberosum L.) is also vegetatively propagated high demand cash crop. A field experiment was carried out in temperate climate to investigate the influence of geranium intercropping at different row strips (1:1 and 1:2) and plant density (60 x 45, 75 x 45 and 90 x 45 cm) with potato intercrop on biomass, oil yield, monetary advantage and soil quality parameters. The row spacing 60x45cm and row strip 1:1 was found to be superior and produced 92 t ha(-1) and 14 kg ha(-1) biomass and oil yield, respectively. The row strip 1:2 intercrop earned a maximum $2107, followed by $1862 with row strip 1:1 at 60 x 45 cm plant density. Significant variations were noticed in soil organic carbon (Corg), total N (Nt), available nutrients, soil microbial biomass (Cmic) and nitrogen (Nmic) content. Maximum improvement of Corg (41.0%) and Nt (27.5%)with row strip 1:1 at 75 x 45 cm plant density. While higher soil respiration rate, Cmic, Nmic, and qCO2 was found with 1:2 row strip at 60 x 45 plant density. The buildup of Corg and Cmic potato intercrop can promote long term sustainability on productivity and soil health.

A raiz de pelargónio / The pelargonium root

En este artículo se presentan los principales componentes activos, actividad farmacológica y aplicaciones terapéuticas de la raíz de pelargonio (Pelargonium sidoides y P. reniforme), droga incluida recientemente en la Farmacopea Europea, así como los ensayos clínicos y meta-análisis realizados (AU)

The traditional uses, bioactive compounds, pharmacology, therapeutic indications with clinical studies and metaanalysis of the pelargonium root (Pelargonium sidoides and P. reniforme), recently introduced in the European Pharmacopoeia, are presented (AU)

Macroevolutionary data suggest a role for reinforcement in pollination system shifts.

Reproductive isolation can evolve either as a by-product of divergent selection or through reinforcement. We used the Cape flora of South Africa, known for its high level of pollination specialization, as a model system to test the potential role of shifts in pollination system in the speciation process. Comparative analysis of 41 sister-species pairs (representing Geraniaceae, Iridaceae, and Orchidaceae) for which complete pollinator, edaphic, and distribution data are available showed that for sister species with overlapping distribution ranges, pollination system shifts are significantly associated with edaphic shifts. In contrast, there is no significant association between pollination system shifts and edaphic shifts for allopatric sister species. These results are interpreted as evidence for reinforcement.