Historical biogeography of Pomaderris (Rhamnaceae): Continental vicariance in Australia and repeated independent dispersals to New Zealand.

AIM: Gondwanan biogeographic patterns include a combination of old vicariance events following the breakup of the supercontinent, and more recent long-distance dispersals across the southern landmasses. Floristic relationships between Australia and New Zealand have mostly been attributed to recent dispersal events rather than vicariance. We assessed the biogeographic history of Pomaderris (Rhamnaceae), which occurs in both Australia and New Zealand, by constructing a time-calibrated molecular phylogeny to infer (1) phylogenetic relationships and (2) the relative contributions of vicariance and dispersal events in the biogeographic history of the genus. LOCATION: Australia and New Zealand. METHODS: Using hybrid capture and high throughput sequencing, we generated nuclear and plastid data sets to estimate phylogenetic relationships and fossil calibrated divergence time estimates for Pomaderris. BioGeoBEARS and biogeographical stochastic mapping (BSM) were used to assess the ancestral area of the genus and the relative contributions of vicariance vs dispersal, and the directionality of dispersal events. RESULTS: Our analyses indicate that Pomaderris originated in the Oligocene and had a widespread Australian distribution. Vicariance of western and eastern Australian clades coincides with the uplift of the Nullarbor Plain c. 14 Ma, followed by subsequent in-situ and within-biome diversification with little exchange across regions. A rapid radiation of southeastern Australian taxa beginning c. 10 Ma was the source for at least six independent long-distance dispersal events to New Zealand during the Pliocene-Pleistocene. MAIN CONCLUSIONS: Our study demonstrates the importance of dispersal in explaining not only the current cross-Tasman distributions of Pomaderris, but for the New Zealand flora more broadly. The pattern of multiple independent long-distance dispersal events for Pomaderris, without significant radiation within New Zealand, is congruent with other lowland plant groups, suggesting that this biome has a different evolutionary history compared with the younger alpine flora of New Zealand, which exhibits extensive radiations often following single long distance dispersal events.

Toxicological and pharmacological evaluation of Discaria americana Gillies & Hook (Rhamnaceae) in mice

Medicinal plants (e.g. Discaria americana) have been used by populations for centuries. However, popular use is not enough to validate these plants as safe and effective medicinal products. The present study sought to evaluate the acute and subacute toxicity as well as the anxiolytic and antinociceptive effects of D. americana root bark and aerial parts extracts in mice. In acute toxicity studies, mice were treated with single intraperitoneal doses of the aforementioned extracts. Subacute toxicity studies were performed by oral administration of the extracts over 14 days. Anxiolytic studies consisted of the elevated plus maze method, and antinociceptive studies were based on the hot plate test. The LD50 value for D. americana aerial parts extract was established at >500 mg/kg, and for the root bark extract, 400 mg/kg. D. americana aerial parts extract produced anxiolytic (250 mg/kg) and antinociceptive effects (125, 200 and 250 mg/kg). Conversely, D. americana root bark extract showed neither anxiolytic nor antinociceptive effects in mice.

As plantas medicinais (i. e. Discaria americana) têm sido utilizadas pela população por séculos, entretanto, o conhecimento popular não é suficiente para validá-las como medicamentos seguros e/ou efetivos. Assim, o presente estudo teve por objetivo avaliar a toxicidade aguda e subaguda, bem como o efeito ansiolítico e antinociceptivo dos extratos da casca da raiz e das partes aéreas da D. americana em camundongos. A toxicidade aguda foi avaliada pela administração dos extratos, via intraperitoneal. Para o estudo da toxicidade subaguda os animais foram tratados oralmente com os extratos por 14 dias. O efeito ansiolítico dos extratos foi determinado através do modelo do labirinto em cruz elevado e o efeito antinociceptivo, mediante o teste da placa quente. O valor da DL50 para o extrato das partes aéreas da D. americana foi definido como > 500 mg/kg, enquanto que para o extrato da casca da raiz foi estabelecido em 400 mg/kg. O extrato das partes aéreas da D. americana apresentou atividade ansiolítica (250 mg/kg) e antinociceptiva (125, 200 e 250 mg/kg). O extrato da casca da raiz da D. americana não apresentou efeito ansiolítico nem antinociceptivo.

[The species basis of Berchemia lineata and its drug commodity].

OBJECTIVE: To investigate the original plant, distribution and efficacy of Radix Seu Stem Berchemiae (Tie Bao Jin) in Zhuang Region of Guangxi and southwest China. METHODS: The original plants of Tie Bao Jin were identified by methods of commodity investigation, specimen collection, literature reference and specimens identification. RESULT: The clinical commonly used as Tie Bao Jin original plant in Zhuang Region of Guangxi were identified as the stem and root of Berchemia lineata (L.) DC, Berchemia polyphylla Wall. ex Laws., Berchemia polyphylla Wall. ex Lawson var. leioclada (Hand. -Mazz. ) Hand. -Mazz. and Berchemia floribunda (Wall.) Brongn. CONCLUSION: Actually, the stem and root of the four plants have been used as Tie Bao Jin in southwest China. And their plant resource include their identification, pharmacodynamics action and the clinical difference still need further research.

[Pollen dispersion and reproductive success of four tree species of a xerophytic forest from Argentina]. / Dispersión polínica y éxito reproductive de cuatro especies arbóreas de un bosque xerófito de Argentina.

The "talares" in eastern Buenos Aires province, Argentina, are coastal xerophitic forests structured by few arboreal species surrounded by a lower and moister soil matrix. We studied the reproductive parameters of the most representative arboreal species (Celtis tala, Scutia buxifolia, Jodina rhombifolia, and Schinus longifolia). Pollen dispersion was studied through floral visitor traps (biotic dispersion) and using gravimetric pollen collectors (abiotic dispersion). The reproductive success (fruit formation rate) of the focal species was studied by enclosing flowers with different mesh bags. The reproductive system varied among the different species. C. tala was anemophilous and selfcompatible. S. buxifolia was entomophilous and floral visitors dependant. J. rhombifolia was entomophylous, although spontaneous autogamy could favor reproduction in the absence of pollinators. Lastly, S. longifolia could be an ambophilous species (pollinated by insects and by the wind). This dual system may be the result of system flexibility mechanism or an evolutionary transition.

Dispersión polínica y éxito reproductivo de cuatro especies arbóreas de un bosque xerófito de Argentina

Pollen dispersion and reproductive success of four tree species of a xerophytic forest from Argentina. The "talares" in eastern Buenos Aires province, Argentina, are coastal xerophitic forests structured by few arboreal species surrounded by a lower and moister soil matrix. We studied the reproductive parameters of the most representative arboreal species (Celtis tala, Scutia buxifolia, Jodina rhombifolia,and Schinus longifolia). Pollen dispersion was studied through floral visitor traps (biotic dispersion) and using gravimetric pollen collectors (abiotic dispersion). The reproductive success (fruit formation rate) of the focal species was studied by enclosing flowers with different mesh bags. The reproductive system varied among the different species. C. tala was anemophilous and selfcompatible. S. buxifolia was entomophilous and floral visitors dependant. J. rhombifolia was entomophylous, although spontaneous autogamy could favor reproduction in the absence of pollinators. Lastly, S. longifolia could be an ambophilous species (pollinated by insects and by the wind). This dual system may be the result of system flexibility mechanism or an evolutionary transition. Rev. Biol. Trop. 57 (1-2): 283-292. Epub 2009 June 30.

Los "talares" del E de la provincia de Buenos Aires son bosques xerófitos costeros estructurados por pocas especies arbóreas rodeados de una matriz de suelos más bajos y húmedos. Estudiamos los parámetros reproductivos de las especies arbóreas más representativas (Celtis tala, Scutia buxifolia, Jodina rhombifolia y Schinus longifolia). La dispersión polínica fue estudiada a través de trampas para visitantes florales (dispersión biótica) y utilizando recolectores gravimétricos de polen (dispersión abiótica). El éxito reproductivo (tasa de formación de frutos) de las especies focales fue estudiado a través de embolsado de flores con bolsas de distintos tipos de malla. El sistema reproductivo varió entre las especies. C. tala resultó anemófila y autocompatible, S. buxifolia fue entomófila y dependiente de los visitantes florales. J. rhombifolia fue una especie entomófila, aunque la autogamia espontánea podría favorecer al aseguramiento reproductivo en caso de falta de polinizadores. Finalmente, S. longifolia podría ser una especie ambófila (polinizada por insectos y por el viento). Este sistema dual podría ser el resultado de un mecanismo de flexibilidad del sistema de polinización o una transición evolutiva.