994 resultados para ASTERACEAE
Resumo:
The presence of Ursinia nana, an Anthemideae of South-African origin which has been introduced into the NE Iberian Peninsula, is reported for the fi rst time in Europe. The data offered cover its precise location, morphology, chromosome number, ecology and a population census, as well as its life cycle, fl oral structure, reproductive biology and fruit dispersal mechanisms. Of special note are the clear predominance of autogamy (geitonogamy) over xenogamy as a reproductive system and the large number of fruits produced with high and immediate germinative capacity. These characteristics permit rapid colonization by the introduced species, which can become invasive. However, fruit predation by the ant Messor barbarus points to a natural mechanism that helps regulate population growth and makes biological control possible. Finally its possibilities of expansion in the colonized area and of naturalization in the NE Iberian Peninsula are assessed.
Resumo:
S"assenyala per primera vegada la presència de Felicia filifolia, espècie introduïda d"origen sud-africà, a les muntanyes del nord de Falset (Priorat). En el registre de plantes al·lòctones constitueix una novetat corològica per a la flora de Catalunya i de la Península Ibèrica.
Resumo:
Se realiza una revisión taxonómica del género Chamaemelum Miller (Asteraceae) en la Península Ibérica e Islas Baleares. Se proponen dos cambios nomenclaturales: Chamaemelum nobile(L.) All. forma discoideum (Willk.) comb. i stat. nov. y C. fuscatum (Brot.) Vasc. forma minor (Hoffmanns. i Link) comb. i stat. nov. Para cada taxon se da el nombre correcto, así como las correspondientes sinonimias. Se adjunta una clave dicotómica de los táxones reconocidos y una relación de los testimonios de herbario estudiados.
Resumo:
The genus Artemisia is one of the largest of the Asteraceae family, with more than 500 species. It is widely distributed mainly across the Northern Hemisphere, being profusely represented in the Old World, with a great centre of diversification in Asia, and also reaching the New World. The evolution of this genus has been deeply studied using different approaches, and polyploidy has been found to perform an important role leading to speciation processes. Karyological, molecular cytogenetic and phylogenetic data have been compiled in the present review to provide a genomic characterization throughout some complexes within the genus.
Resumo:
Se han estudiado desde el punto de vista cariológico un total de 14 poblaciones de ocho táxones de Artemisia L., todos los representantes ibéricos de la sección Artemisia y uno de la sección Seriphidium Bess. Para seis de los ocho táxones se han confeccionado los cariótipos. La mayoría de los recuentos representan novedad en material ibérico, y uno es nuevo para la Ciencia. Los resultados muestran la existencia de dos números de base (x = 8; x = 9) en el género y un grado de simetría de los cariótipos bastante alto. Para cada grupo de especies tratado se hace, además de los comentarios puramente cariológicos, alguno corológico o sistemático.
Resumo:
Cheirolophus intybaceus es una especie heliófila propia de los matorrales mediterráneos termófilos que crece en una franja litoral de unos 50 km de anchura que va desde Tolón (Var, Francia) hasta el sur de la península Ibérica, estando también presente en las islas Baleares (excepto en Menorca). Se encuentra también en las zonas elevadas y soleadas de las cuencas fluviales mediterráneas, formando un complejo de táxones estrechamente relacionados entre sí. Los objetivos de este trabajo son: i) contribuir a la aportación de datos de tamaño del genoma para diversas especies de Asteraceae; ii) estudiar la variación de la cantidad de ADN a lo largo del área de distribución de una especie; iii) evaluar la capacidad de discriminación de este parámetro a niveles taxonómicos bajos. Se ha encontrado una correlación positiva y significativa entre la cantidad de ADN y la latitud, es decir, que en hábitats con menor pluviosidad y más cálidos el tamaño del genoma tiende a disminuir en esta especie. La variación en todo el área de distribución de Ch. intybaceus es de 1,15 veces. Nos encontramos, por lo tanto, ante un caso de baja variabilidad que apoya la constancia del valor 2C.
Resumo:
The Baccharis genus is represented by more than 500 species distributed mainly in the tropical areas of South America. Many of them are extensively used in folk medicine in the treatment or prevention of anemias, inflammations, diabetes and stomach, liver and prostate diseases. Phytochemical and biological investigations in about 120 species resulted mainly in the isolation of clerodane and labdane diterpenes and flavonoid aglicones with the flavone unit being the most frequent.
Resumo:
Endophytes live in association with host plants during all or part of their life cycle without causing any apparent disease. They are considered outstanding and underexploited sources of novel bioactive compounds. Chaetomium globosum was isolated as an endophytic fungus from the healthy leaves of Viguiera robusta. C.globosum is a remarkable producer of chaetoglobosins, which are typically cytotoxic. In this work, chaetoglobosins B (1), D (2) and E (3) have been produced by the endophytic C. globosum strain. Chaetoglobosin B was evaluated against Jurkat (leukemia) and B16F10 (melanoma) tumoral cells and showed 89.55% and 57.10% of inhibition at 0.1 mg mL-1, respectively. Chaetoglobosin B also showed weak antibacterial activity against Staphylococcus aureus (MIC 120 µg/mL) and Escherichia coli (MIC 189 µg/mL).
Resumo:
This work reviews the current literature about the chemical constituents and the biological activities of the subtribe Lychnophorinae (Vernonieae, Asteraceae). The notable secondary metabolites are sesquiterpene lactones of furanoheliangolide (goyazensolide and eremantholide types) and flavonoids. Some of its most investigated activities include its anti-inflammatory, analgesic, antimicrobial and cytotoxic activities, specially for the Lychnophora and Eremanthus species. The data presented on this paper not only displayed the role played by the Lychnophorinae species as a source of bioactive compounds, but also reinforced the need of further studies involving the species of such subtribe.
Resumo:
The species Eremanthus mattogrossensis, known as "veludo do cerrado" (cerrado velvet), is native to the Brazilian Cerrado. Because the amount of metabolites present in plants may be influenced by biological and environmental factors, here we conducted an HPLC-DAD-MS/MS investigation of the metabolite concentrations found in the MeOH/H2O extract of the leaves of this species. The main compounds were identified and quantified, and the metabolites were grouped by chemical class (caffeoylquinic acids, flavonoids, and sesquiterpene lactone). Statistical analysis indicated a straight correlation between the quantity of metabolites and seasonality, suggesting that environmental properties elicit important metabolic responses.
Resumo:
This work reports the chemical characterization of Eremanthusgoyzensis essential oil and its toxic effect over Brevipalpus phoenicis. The essential oil displayed a major composition of sesquiterpenes (61.87%) including trans-caryophillene (26.81%) and germacrene-D (13.31%). The fumigation test indicated a promising bioactivity over adult B. phoenicis individuals at 24 h (2.03 µL/L of air) and 48 h (1.08 µL/L of air) of exposition. A brief discussion of essential oils composition and their singular role on the toxic effect over B. phoenicis is provided here. Our results may contribute to a new and profitable use of a species of Brazilian flora on agribusiness.
Resumo:
The chemical investigation of hexane and ethanol extracts from the aerial parts of Vernonia scorpioides resulted in the isolation and characterization of a new polyacetylene lactone, rel-4-dihydro-4β-hydroxy-5a-octa-2,4,6-triynyl-furan-2-(5H)-one, along with the new ethyl 3,4-dihydroxy-6,8,10-triynyl-dodecanoate, and seven known compounds: taraxasteryl acetate, lupeyl acetate, lupeol, lupenone, β-sitosterol, stigmasterol and luteolin. The structure of all compounds was determined by spectrometric techniques (HR-ESI-MS, ¹H and 13C NMR and IV) and comparison with published spectral data.
Resumo:
This work describes the isolation of an active flavonoid fraction and identification of isorhamnetin 3-O-β-D-(6''-acetyl)-galactopyranoside from flowers of B. perennis, and also the evaluation of anticholinesterase (AChE) activity of ethanolic extract from flowers (EEF) and the active fraction. The chemical structure of the flavonoid was defined on the basis of spectroscopic ¹H NMR, IR and UV data. EEF or flavonoid reduces AChE activity in vivo, while flavonoid also reduces AChE activity in vitro, showing a value of 1.49 mM for 50% inhibitory concentration (IC50), suggesting potential use as an insecticide or in the treatment of neurodegenerative diseases such as Alzheimer's disease.
Resumo:
The volatile components of the galls induced by the insect Baccharopelma dracunculifoliae (Hemiptera: Psyllidae) on leaves of Baccharis dracunculifolia (Asteraceae) were analyzed by gas chromatography-mass spectrometry (GC-MS) and gas chromatographyflame- ionisation detection (GC-FID), and then comparison with volatile oil samples from healthy leaves collected in the vicinity. The galls produced around 3.5% of the total organic volatiles whereas healthy leaves rendered an average yield of 0.6%. The observed higher proportions of germacrene D, bicyclogermacrene, limonene, and β-pinene in the galls suggest that all these compounds are important targets in the search for natural enemies of this Psyllid. Moreover, higher relative percentages of (E)-nerolidol and spathulenol were found in healthy leaves.
Resumo:
Em 2001, plantas de chicória (Cichorium endivia) originárias do município de Catalão-GO apresentando sintomas de manchas e queima foliar foram recebidas na Clínica Fitopatológica da Embrapa Hortaliças (CNPH). Tecidos submetidos à câmara úmida produziram esporulação fúngica, de onde foi obtida cultura monospórica em BDA + cloranfenicol. Para o teste de patogenecidade, o fungo foi multiplicado em meio de cultura suco de tomate ágar (ST) e inoculado em plantas de chicória da cultivar comercial AG-3804, em casa-de-vegetação. Após dez dias de incubação, verificou-se nas plantas inoculadas a presença de sintomas, semelhantes àqueles observados inicialmente. O patógeno foi reisolado a partir destas lesões, completando os postulados de Koch. Em seguida, visando testar a possibilidade deste patógeno infetar outras plantas da família Asteraceae, conídios produzidos em ST e atomizados em plantas de alface (Lactuca sativa) (três variedades), almeirão (Cichorium intybus) (duas variedades), Catalonha (Cichorium intybus) folha fina, serralha (Sonchus oleraceus) e uma outra variedade de chicória. Houve infecção em todas as plantas inoculadas, sendo que os sintomas variaram nas espécies e nas variedades testadas. Em chicória os sintomas surgiram mais cedo e se desenvolveram rapidamente. O fungo foi caracterizado morfológica e morfometricamente permitindo identificá-lo como sendo Alternaria cichorii. Não se encontra registro desta espécie de Alternaria infetando plantas da família Asteraceae no Brasil. Neste trabalho relata-se pela primeira vez, a ocorrência de A. cichorii infetando chicória no Brasil e o potencial deste fungo como patógeno de outras espécies da família Asteraceae.