9,616 research outputs found

    Influence of Cladonia substellata Vainio extracts and usnic acid on germination and growth of Allium cepa L. seedlings

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    The effect of lichen extracts obtained from Cladonia substellata and its main constituent, on the germination and growth of onion (Allium cepa L.) seedlings was investigated. No significant inhibitory effect of the lichen extracts and usnic acid on germination was found, except of usnic acid at the concentration of 726.7 mM. Growth inhibition of the radicle and of the hypocotyl of the seedlings was found for the total extract and for usnic acid in concentrations of 290.6 mM and 726.7 mM

    Allelopathic effect of the Cladonia verticillaris lichen extracts and fumarprotocetraric acid on the early growth of germinated seedlings in Allium cepa L.

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    The allelopathic activity of the different type of Cladonia verticillaris lichen extracts and fumarprotocetraric acid on the early growth of A. cepa (IPA 6) germinated seedlings depends on their chemical composition and concentration, respectively. It was observed that the length of the radicle was significantly stimulated by fumarprotocetraric acid at high concentrations and by the total extract of C. verticillaris thalli, which contained high level of fumarprotocetraric, acid confirmed by HPLC – technique. In addition, it was found, that the phosphate buffer extract, which contained high level of methy betha-orcinol carboxilate measured by HPLC, significantly reduced the length of the hypocotyls. Under our experimental conditions there was no influence of different type of extract and fumarprotocetraric acid on the seed germination ratio of A. cepa, in relation to control. From the study of HPLC it was found that fumarprotocetraric acid and methy betha-orcinol carboxilate were present in all extracts at different concentrations, according to the method of extraction

    Quando o documentário pensa, Frederick Wiseman

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    In the cinema in general and particularly in documentary it is very difficult to separate the social concern of one film from its political nature. In his fundamental work in contemporary documentary, Frederick Wiseman shooted some of themost relevant institutions of American society with a declared social concern but alsowith an ethical look and an expression of political thought.Keywords

    A jazida do Eemiano da Baia de Nossa Senhora da Luz (Santiago, Cabo Verde)

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    A secção UAciência é coordenada pelo Professor Universitário Armindo Rodrigues.[…]. Numa perspetiva de alargar o nosso conhecimento sobre os processos e padrões de dispersão de espécies marinhas, os estudos paleontológicos da equipa do CIBIO-Açores estenderam-se ao arquipélago de Cabo Verde, com um foco particular na ilha de Santiago, onde se encontra uma das maiores jazidas fossilíferas (monoespecífica) existentes no Atlântico Norte, a jazida da Baia de Nossa Senhora da Luz. Esta jazida é marcante, não só pelo seu tamanho, cobrindo uma área de cerca de 35.000m² (equivalente à dimensão de cerca de 5 campos de futebol profissional), mas também pela natureza da sua origem, pois corresponde à primeira paleobaía descrita para o ultimo estádio interglacial no contexto da região geográfica da Macaronésia. Foram realizadas 4 campanhas de campo entre 2017 e 2019, que resultaram num conhecimento aprofundado sobre os processos que conduziram à formação desta jazida. Das amostras fósseis recolhidas, foram identificados 5 filos marinhos (29 géneros), sendo o filo dos moluscos (Mollusca), o melhor representado. […].info:eu-repo/semantics/publishedVersio
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