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1.
Summary  Seven new names at species rank are proposed in Memecylon sect. Afzeliana Jacq.-Fél., a group of forest shrubs and small trees confined to Guineo-Congolian Africa. The group is centred in Cameroon, where 17 of the 20 species occur. A new flower type, the “star-flower” in Memecylon is revealed, and its taxonomic and ecological importance discussed. Three new, locally endemic species from the South West Province of Cameroon are described, mapped and illustrated: M. kupeanum R. D. Stone, Ghogue & Cheek, M. bakossiense R. D. Stone, Ghogue & Cheek, and M. rheophyticum R. D. Stone, Ghogue & Cheek. Two new names, M. accedens R. D. Stone, Ghogue & Cheek and M. hyleastrum R. D. Stone & Ghogue and one new combination, M. mamfeanum (Jacq.-Fél.) R. D. Stone, Ghogue & Cheek are provided at species level for three taxa originally proposed as varieties of M. afzelii G. Don. The taxon M. arcuatomarginatum var. simulans Jacq.-Fél. is also elevated to species status, as M. simulans (Jacq.-Fél.) R. D. Stone & Ghogue. Conservation assessments are provided for all the newly named taxa. A key is provided to the species of Memecylon sect. Afzeliana.  相似文献   

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Summary  Three closely affiliated species of Heterospathe Scheff. (H. elegans (Becc.) Becc., H. humilis Becc. and H. versteegiana Becc.) from New Guinea are revised. They are reduced to a single species which is divided into two subspecies, and the new combination H. elegans subsp. humilis (Becc.) M. S. Trudgen & W. J. Baker is made. The subspecies can be readily distinguished by their growth habit. Epitypes are designated for the three previously published names, as informative material on the habit is not included in the existing type specimens. A new, potentially related species is described as H. pullenii M. S. Trudgen & W. J. Baker.  相似文献   

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Summary   Erythroxylum longisetulosum I. Loiola & M. F. Sales and E. timothei I. Loiola & M. F. Sales (sect. Rhabdophyllum) from north-eastern Brazil are described and illustrated, and their taxonomic and ecological relationships are discussed.  相似文献   

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Summary  A new species of Dioscorea from Morondava prefecture in Western Madagascar is described. Dioscorea bako Wilkin differs from D. alatipes Burkill & H. Perr. by its usually shallowly and irregularly lobed leaf margins, broader leaf blade (grey-green below), longer petiole and the broadly cuneate area where the petiole is inserted onto the leaf blade in the basal sinus. It is pubescent, especially densely on young shoots and inflorescences. It is endemic to Morondava Préfecture and is endangered under IUCN Red List category criteria (IUCN 2001). The unusual morphological features of its inflorescences, some of which are shared with D. alatipes are discussed. Dioscorea bako is a favoured food source for people of the Menabe region and is reported by them to be increasingly hard to find. Immediate conservation measures are necessary to ensure that it remains extant and, in the medium to long term, research should be undertaken to guide its sustainable utilisation.  相似文献   

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P transposons belong to the eukaryotic DNA transposons, which are transposed by a cut and paste mechanism using a P-element-coded transposase. They have been detected in Drosophila, and reside as single copies and stable homologous sequences in many vertebrate species. We present the P elements Pcin1, Pcin2 and Pcin3 from Ciona intestinalis, a species of the most primitive chordates, and compare them with those from Ciona savignyi. They showed typical DNA transposon structures, namely terminal inverted repeats and target site duplications. The coding region of Pcin1 consisted of 13 small exons that could be translated into a P-transposon-homologous protein. C. intestinalis and C. savignyi displayed nearly the same phenotype. However, their P elements were highly divergent and the assumed P transposase from C. intestinalis was more closely related to the transposase from Drosophila melanogaster than to the transposase of C. savignyi. The present study showed that P elements with typical features of transposable DNA elements may be found already at the base of the chordate lineage. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

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Summary  A new and probably endemic species of Cambessedesia DC. is described from campo rupestre vegetation, as part of a floristic survey of Melastomataceae from the S?o José mountain range, Tiradentes District, Minas Gerais State, Brazil. Miscellaneous  Accepted for publication April 2008.  相似文献   

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Summary   Linaria khalkhalensis Hamdi & Assadi is described as a new species from Azerbaijan and Guilan provinces (northern Iran), belonging to Linaria sect. Linaria. It is close to Linaria lineolata Boiss. and L. elymaitica (Boiss.) Kuprian., which it resembles in habit and vegetative features. However, floral and seed characters together with a distinctive geographical distribution, warrant recognition at the species rank. An illustration of the new species, a distribution map, scanning electron micrographs of seed and capsule surfaces, and an identification key are also included.  相似文献   

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Summary   Funastrum rupicola Goyder, a new species of Apocynaceae: Asclepiadoideae from Bolivia, is described and illustrated. The conservation status of this species is assessed.  相似文献   

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We studied five reproductive attributes (fruit production and volume, seed content and weight, and seed germination) of different populations of Campanula species occurring along the elevation gradient of Mt Olympos, the highest mountain of Greece (2917 m), in order to examine whether and how they change with elevation, and if there are trade-offs among them. We also studied flower and fruit (reproductive) losses and population features in order to estimate whether there might be a threat to the survival of Campanula species on Mt Olympos. The genus is represented by nine species, ranging from cosmopolitan to steno-endemic. All species were found non-autogamous, and hence they depend on pollinators for their sexual reproduction. At the genus level, there is a trade-off between seed content per fruit and seed weight. At the species level, this is manifested only for C. glomerata, which produces the heaviest seeds, far exceeding all other species, and for C. spatulata, represented on Mt Olympos by two elevation distinct subspecies. Changes of the reproductive attributes are not continuous all along the elevation gradient at the genus level nor are they monotonic at the species level. Nevertheless, upland Campanula populations (≥1500 m) produce fewer fruits per individual, containing fewer but heavier seeds than lowland populations. This indicates a transition from ‘r’ to ‘K’ strategies, from low to high elevations, respectively. The patterns of change of reproductive attributes indicate prevalence of phylogenetic over environmental constraints. Laboratory tests showed that for many populations germinability is high at 15 °C, but there are both inter- and intraspecific differences regarding temperature optima. Ecotypic variation among populations of the same species at different elevations was evident; populations from higher elevations had lower optima and vice versa. Reproductive losses, ranging from zero to over 90%, occurred mainly at the stage of fruit maturation; grazing by sheep and goats was the usual cause. Though such losses might affect the short-lived species (the annual C. sparsa and the biennial C. lingulata), which depend entirely on fruit maturation and seed dispersal for their reproduction, there does not seem to be a serious threat to the survival of Campanula species on the mountain.  相似文献   

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Summary  A new monotypic bamboo genus Phuphanochloa (Poaceae: Bambusoideae) from north-eastern Thailand is described, together with a new species, P. speciosa.  相似文献   

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The maT clade of transposons is a group of transposable elements intermediate in sequence and predicted protein structure to mariner and Tc transposons, with a distribution thus far limited to a few invertebrate species. We present evidence, based on searches of publicly available databases, that the nematode Caenorhabditis briggsae has several maT-like transposons, which we have designated as CbmaT elements, dispersed throughout its genome. We also describe two additional transposon sequences that probably share their evolutionary history with the CbmaT transposons. One resembles a fold back variant of a CbmaT element, with long (380-bp) inverted terminal repeats (ITRs) that show a high degree (71%) of identity to CbmaT1. The other, which shares only the 26-bp ITR sequences with one of the CbmaT variants, is present in eight nearly identical copies, but does not have a transposase gene and may therefore be cross mobilised by a CbmaT transposase. Using PCR-based mobility assays, we show that CbmaT1 transposons are capable of excising from the C. briggsae genome. CbmaT1 excised approximately 500 times less frequently than Tcb1 in the reference strain AF16, but both CbmaT1 and Tcb1 excised at extremely high frequencies in the HK105 strain. The HK105 strain also exhibited a high frequency of spontaneous induction of unc-22 mutants, suggesting that it may be a mutator strain of C. briggsae.  相似文献   

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Summary  Two new combinations, one new and one resurrected name in Plectranthus L’Hér. are provided for species formerly placed in Leocus A. Chev.; conservation assessments are made for five species.  相似文献   

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It has been shown previously that the rolC gene from Agrobacterium tumefaciens gene was stably and highly expressed in 15-year-old Panax ginseng transgenic cell cultures. In the present report, we analyze in detail the nucleotide composition of the rolC and nptII (neomycin phosphotransferase) genes, which is the selective marker used for transgenic cell cultures of P. ginseng. It has been established that the nucleotide sequences of the rolC and nptII genes underwent mutagenesis during cultivation. Particularly, 1–4 nucleotide substitutions were found per sequence in the 540 and 798 bp segments of the complete rolC and nptII genes, respectively. Approximately half of these nucleotide substitutions caused changes in the structure of the predicted gene product. In addition, we attempted to determine the rate of accumulation of these changes by comparison of DNA extracted from P. ginseng cell cultures from 1995 to 2007. It was observed that the frequency of nucleotide substitutions for the rolC and nptII genes in 1995 was 1.21 ± 0.02 per 1,000 nucleotides analyzed, while in 2007, the nucleotide substitutions significantly increased (1.37 ± 0.07 per 1,000 nucleotides analyzed). Analyzing the nucleotide substitutions, we found that substitution to G or to C nucleotides significantly increased (in 1.9 times) in the rolC and nptII genes compared with P. ginseng actin gene. Finally, the level of nucleotide substitutions in the rolC gene was 1.1-fold higher when compared with the nptII gene. Thus, for the first time, we have experimentally demonstrated the level of nucleotide substitutions in transferred genes in transgenic plant cell cultures.  相似文献   

19.
Two extracellular chitinases were purified from Paecilomyces variotii DG-3, a chitinase producer and a nematode egg-parasitic fungus, to homogeneity by DEAE Sephadex A-50 and Sephadex G-100 chromatography. The purified enzymes were a monomer with an apparent molecular mass of 32 kDa (Chi32) and 46 kDa (Chi46), respectively, and showed chitinase activity bands with 0.01% glycol chitin as a substrate after SDS-PAGE. The first 20 and 15 N-terminal amino acid sequences of Chi32 and Chi46 were determined to be Asp-Pro-Typ-Gln-Thr-Asn-Val-Val-Tyr-Thr-Gly-Gln-Asp-Phe-Val-Ser-Pro-Asp-Leu-Phe and Asp-Ala-X-X-Tyr-Arg-Ser-Val-Ala-Tyr-Phe-Val-Asn-Trp-Ala, respectively. Optimal temperature and pH of the Chi32 and Chi46 were found to be both 60°C, and 2.5 and 3.0, respectively. Chi32 was almost inhibited by metal ions Ag+ and Hg2+ while Chi46 by Hg2+ and Pb2+ at a 10 mM concentration but both enzymes were enhanced by 1 mM concentration of Co2+. On analyzing the hydrolyzates of chitin oligomers [(GlcNAc) n , n = 2–6)], it was considered that Chi32 degraded chitin oligomers as an exo-type chitinase while Chi46 as an endo-type chitinase.  相似文献   

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Summary   Typhonium stigmatilobatum V. D. Nguyen, a new species from Vietnam, is described and illustrated.  相似文献   

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