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In vivo administration experiments using stable (13C) and radio (14C) labeled precursors established that the optically active 8-2' linked lignans, (-)-cis-blechnic, (-)-trans-blechnic and (-)-trans-brainic acids, were directly derived from L-phenylalanine, cinnamate, and p-coumarate but not either from tyrosine or acetate. The radiochemical time course data suggest that the initial coupling product is (-)-cis-blechnic acid, which is then apparently converted into both (-)-trans-blechnic and (-)-trans-brainic acids in vivo. These findings provide additional evidence for vascular plant proteins engendering distinct but specific phenolic radical-radical coupling modes, i.e., for full control over phenylpropanoid coupling in vivo, whether stereoselective or regiospecific. 相似文献
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Our aim was to evaluate the potential of existing herbarium collections in reconstructing the past population history of the
rediscovered clone of the regionally extinct Blechnum spicant by comparing it with herbarium material from previous sites of occurrences in Finland and elsewhere in northern Europe, as
well as to reveal the genetic and geographic relationship among the samples. We detected a total of nine polymorphic sites
within the three sequenced regions, two SCAR markers developed now for B. spicant and the chloroplast trnL-trnF spacer, totalling 763 bp. Despite low variability, the phylogeographic analysis revealed the presence of some geographic
pattern among the samples, of which all except one represented herbarium samples of up to 100 years of age. The rediscovered
clone of B. spicant proved to represent the prevalent genotype occurring in northern Europe. The studied sequences were neutral in terms of evolution.
It is apparent that existing herbarium collections are useful resources for a range of evolutionary and population studies. 相似文献
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Maria Do Carmo M. Miraglia Adolfo P. De Pádua Antonio A.L. Mesquita Otto R. Gottlieb 《Phytochemistry》1985,24(5):1120
From the leaves of the fern Pityrogramma ebenea a new compound 2′,6′-dihydroxy-4,3′-dimethoxy-4′,5′-methylenedioxydihydrochalcone was characterized. (2S)-5,7-Dihydroxy-4′-methoxy-6,8-dimethylflavanone was identified in another fern, Blechnum regnellianum 相似文献
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New glycosides having multisubstituted cyclohex-2-enones as aglycones and saccharide moieties consisting of three and four glucoses, respectively were isolated from the ethanol extract of the American fern Woodwardia virginica. The structures were elucidated using extensive spectroscopic analysis (1D and 2D NMR, MS, IR, CD and UV) including determination of absolute stereochemistry by chemical methods. 相似文献
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Alexander Fco Rojas-Alvarado 《Brittonia》2006,58(4):388-394
Blechnum moranianum is a new species similar toB. loxense, andB. nigrum is segregated from theB. fragile complex. Both are described and illustrated as result of the author's taxonomic fern work in Costa Rica.
Blechnum moranianum es una especie nueva similar aB. loxense, yB. nigrum es segregada del complejoB. fragile. Ambas son aquí descritas e ilustradas como resultado de los trabajos taxonómicos del autor en los helechos de Costa Rica. 相似文献
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Identification of 6 apigeninidin and 6 luteolinidin anthocyanins from the fern Blechnum procerum (Forst. f) Schwartz is reported. 相似文献
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Ezequiel Ignacio Vera 《Geobios》2010,43(4):465
The study of abundant permineralized fern remains collected in the Oligocene Rancahué Formation (Neuquén Province, Argentina) allowed the identification of two different taxa. The name Cuyenopteris patagoniensis nov. gen., nov. sp. is proposed for several stems and fronds characterized by the presence of caulinar dictyosteles with root gaps, producing C-shaped leaf traces composed by two hippocampiform bundles flanked by eight to ten small round bundles, half of them diverging from cauline meristeles and the rest from the hippocampiform bundles. The presence of these features, along with frond bases with adaxial grooves and a pair of pneumatophores, suggest affinities with the Blechnaceae or Dryopteridaceae. The second identified taxon is Alsophilocaulis calveloi Menéndez. Based on features observed in these new materials, including characteristics of the mantle of adventitious roots and anatomy of the petiole bases, an emended diagnosis for this latter species is proposed. 相似文献