Recent evidence suggests that the traditional view of myrmecochory as a highly diffuse interaction between diaspores and a wide range of ant species attracted to their elaiosomes may not be correct. The effectiveness of dispersal varies markedly among ant species, and combined with differential attractiveness of diaspores due to elaiosome size and composition, this raises the potential for myrmecochorous plants to target ant species that offer the highest quality dispersal services. We ask the question: Do particular physical and chemical traits of elaiosomes result in disproportionate removal of Euphorbiaceae diaspores by high-quality disperser ants in Caatinga vegetation of north-eastern Brazil? We offered seeds of five euphorb species that varied in morphological and chemical traits of elaiosomes to seed-dispersing ants. High-quality seed-disperser ants (species of Dinoponera, Ectatomma and Camponotus) were identified as those that rapidly collected and transported diaspores to their nests, often over substantial distances, whereas low-quality disperser ants (primarily species of Pheidole and Solenopsis) typically fed on elaiosomes in situ, and only ever transported diaspores very short distances. Low-quality disperser ants were equally attracted to the elaiosomes of all study species. However, high-quality dispersers showed a strong preference for diaspores with the highest elaiosome mass (and especially proportional mass). As far as we are aware, this is the first study to identify a mechanism of diaspore selection by high-quality ant dispersers based on elaiosome traits under field conditions. Our findings suggest that myrmecochorous plants can preferentially target high-quality seed-disperser ants through the evolution of particular elaiosome traits.

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The effects of the contents and chemical composition of the foliar epicuticular waxes of species from the caatinga (Aspidosperma pyrifolium, Capparis yco, Maytenus rigida and Ziziphus joazeiro) and cerrado (Aristolochia esperanzae, Didymopanax vinosum, Strychnos pseudoquina and Tocoyena formosa) were evaluated as to the resistance to water loss by means of an experimental device constructed for this purpose. In general, the waxes of the caatinga species investigated were more efficient against water loss than cerrado species. Increase of the thickness of the waxy deposits from 40 to 90µ g.cm −2 had no significant effect on the resistance to water loss. The chemistry of the wax constituents was shown to be an important factor to determine the degree of resistance to evaporation. n-Alkanes and alcoholic triterpenes were the most efficient barriers, while hentriacontan-16-one (a ketone) and ursolic acid (an acid triterpene) revealed low efficiency. The higher efficiency of the waxes of the leaves from caatinga species (mainly those of C. yco and Z. joazeiro) is probably accounted for the predominance of n-alkanes in their composition. The lower efficiency of the waxes of A. pyrifolium (caatinga), T. formosa and A. esperanzae (both species from the cerrado) is probably a consequence of the predominance of triterpenoids in the waxes of the two former species and hentriacontan-16-one in the latter.

In this study, pulp and kernel of fruits from six Arecaceae species were subjected to proximate analysis, fatty acid composition and total carotenoid content analysis. The species with the highest carbohydrate, lipid and protein values were Ptychosperma macarthurii (70.1 g/100 g in the kernel), Syagrus cearensis (40.6 g/100 g in the kernel), and S. coronata (20.6 g/100 g in the pulp). The ash content ranged from 0.61 to 7.51 g/100 g. Lauric, palmitic, and oleic acids were the major fatty acids identified. The total carotenoid contents and retinol activity equivalents were highest in the Pinanga kuhlii (180.3 µg/g) and Acrocomia intumescens (138.0 µg/g) pulp oils. Retinol activity equivalents varied between the investigated species (456 to 1515 μg RAE/100 g). Native species such as A. intumescens, S. coronata, and S. cearensis are good sources of fresh food for the underserved populations that inhabit poorly developed areas such as the semi-arid region of Brazil. P. macarthurii, an exotic species, is an excellent source of ash and carotenoids, demonstrating its potential both as a food source and as bioactive compounds. Pulp and kernel of A. intumescens, could be a good alternative feedstock for soap and biodiesel production, respectively.

IntroduçãoO conhecimento nativo sobre a utilização de plantas medicinais tem sido bem documentado em várias partes do mundo (Begossi et al. 2002). Esta prática tradicional ainda é comum em vários povos, sendo mais evidente nos países em desenvolvimento, onde a maior parte da população pobre não tem acesso aos medicamentos industrializados (Ayyanar & Ignacimuthu 2005).O uso de recursos naturais por populações urbanas de origem rural é orientado por um conjunto de conhecimentos resultantes da relação com o ambiente natural na qual estavam inseridas bem como pelas relações sociais em que estão imersas no meio urbano. Muitos produtos vegetais e suas formas de usos que atualmente são indispensáveis à sociedade urbana têm sua origem nestas populações de origem rural, que aprenderam a domesticar e a manipular as propriedades curativas das plantas (Castelluci et al. 2000). Entretanto, as modernas condições de vida dessas populações comprometem a transmissão desse conhecimento para as futuras gerações, como observado em várias comunidades brasileiras e outros países da América do Sul (Ayyanar & Ignacimuthu 2005;Fonseca-Kruel & Peixoto 2004;Estomba et al. 2005).As plantas medicinais e seus usos terapêuticos são alvos de pesquisas etnobotânicas, que mostram também as circunstâncias sócio-culturais da população e preocupamse em resgatar e valorizar o conhecimento tradicional e a diversidade cultural dessas sociedades estudando a relação entre as plantas e as pessoas de uma maneira multidisciplinar (Benz et al. 2000;Heinrich 2000;Ladio & Lozada 2004). Por estes motivos, pesquisas nesta área foram uma das que mais se desenvolveram nos últimos anos para a descoberta de produtos naturais bioativos (Maciel et al. 2002).Neste trabalho, realizou-se um estudo a respeito do conhecimento e uso de plantas medicinais na comunidade urbana de Muribeca, entre dois grupos considerados conhecedores de plantas medicinais: moradores com treinamento fornecido por organizações governamentais sobre uso e manipulação de plantas medicinais e moradores sem treinamento formal, com conhecimento sobre plantas medicinais transmitido pela tradição oral. A pesquisa foi direcionada para responder à seguinte questão: a aquisição de um conhecimento formal, somado ao já adquirido tradicionalmente sobre uso e manipulação de plantas medicinais, modifi caria a importância das plantas popularmente utilizadas por uma população e/ou suas indicações terapêuticas? A partir deste levantamento etnobotânico as espécies que apresentaram uma maior Importância Relativa foram discutidas objetivando-se detectar alguma relação entre a indicação popular e a validação científi ca. (

The epicuticular waxes of leaves of four species (Aspidospermci pyrifolium, Capparis yco, Maytenus rigida and Ziziphus joazeiro) from the Caatinga, (a semi-arid ecosystem of N orth east Brazil) and four species (Aristolochia esperanzae, Didymopanax vinosum , Strychnos pseudoquina and Tocoyena formosa) from the Cerrado, (a savanna ecosystem covering one third of the Brazilian territory), were analyzed. Six species contained a high content (above 60 (.ig.cm-2) of wax, four of them from the Caatinga. Triterpenoids and rc-alkanes were the most frequent and abundant constituents found in the species from both habitats. The distri bution of «-alkanes predom inated by homologues with 27, 29, 31 and 33 carbon atoms, dis played no consistent differences between species from the two habitats. Lupeol, ß-amyrin, epifriedelinol and ursolic acid were the triterpenoids found. Triterpenoids clearly predomi nate over alkanes in the waxes from the Cerrado species. The waxes of two evergreen species from the Caatinga yielded «-alkanes as predominant constituents. A comparison of foliar epicuticular waxes of native plants from ecosystems with different hydric constraints is dis cussed.

Mangroves represent areas of high biological productivity and it is a region rich in bioactive substances used in medicine production. Conocarpus erectus (Combretaceae) known as button mangrove is one of the species found in mangroves and it is used in folk medicine in the treatment of anemia, catarrh, conjunctivitis, diabetes, diarrhea, fever, gonorrhea, headache, hemorrhage, orchitis, rash, bumps and syphilis. The present study aimed to investigate the acute toxicity of aqueous extract of leaves of C. erectus in Swiss albino mice. The plant material was collected in Vila Velha mangroves, located in Itamaracá (PE). The material was subjected to a phytochemical screening where extractive protocols to identify majority molecules present in leaves were used. The evaluation of acute toxicity of aqueous extract of C. erectus followed the model of Acute Toxicity Class based on OECD 423 Guideline, 2001. The majority molecules were identified: flavonoids, tannins and saponins. The LD 50 was estimated at 2,000 mg/kg bw. Therefore, the aqueous extract showed low acute toxicity classified in category 5.

The contents of the main components of the primary metabolism (soluble sugars, starch, proteins, oils, fatty acids) and minerals (P, Ca, Mg, K, Fe, Zn, Mn, Cu) were characterized in seeds of five Brazilian Amazon tree species (Andira parviflora, Bertholletia excelsa, Helicostylis tomentosa, Hymenaea parviflora, and Parkia pendula). Soluble sugar contents were high in P. pendula seeds (14 %), whereas starch predominated in A. parviflora seeds (58.7 %). A. parviflora and H. parviflora seeds were rich in proteins (35.1 % and 32.4 %, respectively). The oil contents ranged from 1.4 % in A. parviflora to 70.7 % in B. excelsa. Only B. excelsa and P. pendula seeds may be considered oilseeds, with 70.7 % and 28.4 % oil, respectively. The fatty acid compositions showed high proportions of unsaturated fatty acids, mainly oleic and linoleic acids, regardless of the species. B. excelsa and P. pendula also showed high amounts of P, Mg, K and Zn.Key words: Fatty acids, minerals, oils, proteins, soluble sugars, starch.Componentes do metabolismo primário de sementes de espécies arbóreas da Amazônia brasileira: Os conteúdos dos principais componentes do metabolismo primário (açúcares solúveis, amido, proteínas, óleos, ácidos graxos) e de minerais (P, Ca, Mg, K, Fe, Zn, Mn, Cu) foram caracterizados em sementes de cinco espécies arbóreas da Amazônia Brasileira (A. parviflora, B. excelsa, H. tomentosa, H. parviflora e P. pendula). O conteúdo de açúcares solúveis foi maior em P. pendula (14 %) e o de amido predominou em sementes de A. parviflora (58,7 %). Sementes de A. parviflora (35.1 %) e H. parviflora (32.4 %) mostraram-se ricas em proteínas. O conteúdo de óleo variou de 1,4 % em A. parviflora a 70,7 % em B. excelsa. Sementes de P. pendula têm 28,4 % de óleo e junto com sementes de B. excelsa, podem ser consideradas como sementes oleaginosas. Independente da espécie, a composição de ácidos graxos mostrou maior proporção de ácidos graxos insaturados, principalmente ácidos oléico e linoléico. B. excelsa e P. pendula também apresentaram maiores quantidades de P, Mg, K e Zn.