首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   11篇
  免费   0篇
  2011年   2篇
  2010年   1篇
  2008年   1篇
  2007年   1篇
  2006年   1篇
  2003年   2篇
  1985年   1篇
  1981年   1篇
  1974年   1篇
排序方式: 共有11条查询结果,搜索用时 0 毫秒
1.
本文报道了贵州蕨类植物一新记录属——乌木蕨属Blechnidium Moore,该属为乌毛蕨科Blechnaceae一单种属,仅乌木蕨Blechnidium melanopus(Hook.)Moore一种。此物种分布区狭窄,数量有限,在贵州的发现对研究其地理与区系很有意义。  相似文献   
2.
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   
3.
报道了贵州蕨类植物一新记录属——乌木蕨属(Blechnidium Moore),该属为乌毛蕨科(Blechnaceae)一单种属,仅乌木蕨[Blechnidium melanopus(Hook.)Moore]1种。此物种分布区狭窄,数量有限,在贵州的发现对研究其地理与区系很有意义。  相似文献   
4.
乌毛蕨科3种植物配子体发育的研究   总被引:1,自引:0,他引:1  
通过人工培养的方式,详细记录了乌毛蕨科(Blechnacea)具代表性的3个种,即乌毛蕨(Blechnum Orientale L.)、狗脊蕨(Woodwardia Japonica (L.F)Smith)和苏铁蕨(Brainea insignis (Hook)J.Sm)的配子体发育全过程,附特征性结构照片37幅。实验结果基本支持秦仁昌主要依据孢子体形态的分类观点。为乌毛蕨科的研究积累了配子体发育方面的详实资料。  相似文献   
5.
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   
6.
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   
7.
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   
8.
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   
9.
Identification of 6 apigeninidin and 6 luteolinidin anthocyanins from the fern Blechnum procerum (Forst. f) Schwartz is reported.  相似文献   
10.
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   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号