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1.
Bupleurum shanianum X. G. Ma & X. J. He, previously recognized in China as B. gracillimum, is proposed here as a new species. This new species and B. gracillimum differ in many morphological characters (flowering stem position, bract size, number of flowers per umbellule) and have non‐overlapping distribution ranges. Bupleurum shanianum is most similar to B. yunnanense Franch., but the new species has shorter cauline leaves, and umbellules usually with 4 bracteoles and 3–6(–9) flowers. Bupleurum shanianum is known from eastern Himalayas to western Sichuan.  相似文献   

2.
The objective of this study was to develop single‐step PCR species‐specific primers that reliably discriminate four economically important Xiphinema species (X. brevicolle, X. elongatum, X. ifacolum and X. longicaudatum) and X. diffusum that is taxonomically very similar to X. brevicolle. Each species‐specific reverse primer was located in the ITS‐1 rDNA region and was used in combination with a universal forward primer located in the 18S rDNA gene. Primer reliability was confirmed by screening seven and 11 populations, respectively of X. diffusum and X. elongatum. Potential species‐specific primers were also identified for X. brevicolle, X. longicaudatum and X. ifacolum, however too few populations of these species were available to thoroughly assess their reliability. For all species‐specific primers, specificity was demonstrated by the absence of cross‐reactions with 14 non‐target Xiphinema species. Multiplex PCR was effective and reproducible for two (X. longicaudatum and X. ifacolum) or three (X. brevicolle, X. diffusum and X. elongatum) of the target nematode species, thus improving the applicability of the diagnostic primers.  相似文献   

3.
The taxonomic affiliation was determined for four Xenorhabdus strains isolated from four Steinernema hosts from different countries. As compared to the five validly described Xenorhabdus species, i.e., X. nematophila, X. japonica, X. beddingii, X. bovienii and X. poinarii, these isolates represented novel species on the basis of 16S rRNA gene sequences and riboprint patterns, as well as by physiological and metabolic properties. They were named Xenorhabdus budapestensis sp. nov., type strain DSM 16342T, isolated from Steinernema bicornutum; Xenorhabdus ehlersii sp. nov., type strain DSM 16337T, isolated from Steinernema serratum; Xenorhabdus innexi sp. nov., type strain DSM 16336T isolated from Steinernema scapterisci; and Xenorhabdus szentirmaii sp. nov., type strain DSM 16338T, isolated from Steinernema rarum.  相似文献   

4.
Gutiérrez‐Gutiérrez, C., Palomares‐Rius, J.E., Cantalapiedra‐Navarrete, C., Landa, B.B., Esmenjaud, D. & Castillo, P. (2010). Molecular analysis and comparative morphology to resolve a complex of cryptic Xiphinema species. —Zoologica Scripta, 39, 483–498. During nematode surveys in cultivated and natural environments in southern Spain nine populations of parthenogenic Xiphinema species tentatively identified as Xiphinema cf. pyrenaicum and one population morphologically close to Xiphinema turcicum were detected. Surveys in southern France also identified one population resembling X. pyrenaicum. We developed a comparative study among these related Xiphinema species, including topotypes of two species of this group previously synonymized, viz. Xiphinema hispanum and Xiphinema sphaerocephalum, by considering morphological and morphometrical features together with molecular data from nuclear ribosomal RNA genes (D2‐D3 expansion segments of 28S, ITS1, and partial 18S). Morphological and morphometrical results identified eight of the Spanish populations as Xiphinema nuragicum (previously synonymized with X. pyrenaicum) whereas the ninth population was identified as Xiphinema adenohystherum (also synonymized with X. pyrenaicum). The species X. adenohystherum, X. nuragicum, X. pyrenaicum, and X. sphaerocephalum were shown to be morphologically almost indistinguishable but clearly separated by phylogenetic analyses, thus constituting a complex of cryptic species. Consequently, X. adenohystherum, X. nuragicum, and X. sphaerocephalum were re‐established as valid species. Similarly, X. hispanum (morphologically similar to X. aceri) was also shown as a valid species. Xiphinema turcicum, morphologically related to X. pyrenaicum complex by its rounded tail, uterus with a pseudo‐Z‐differentiation and small spines, was phylogenetically distant to these species based on D2‐D3 expansion segments of 28S and ITS1, which suggests a morphological convergence in their evolution.  相似文献   

5.
As a part of the revision of Xiphion (Iris subg. Xiphion) for the ‘Flora Iberica’ project, some material collected in the 19th and 20th centuries in the Tangiers area (northern Morocco) was found impossible to assign to any of the known taxa in the genus. In part, they resembled X. junceum and X. rutherfordii, but showed a peculiar combination of vegetative and floral characters which to date is exclusive. Accordingly, the new species X. heracleanum Mart. Rodr. & M. B. Crespo is described for these plants, and evidence is reported to justify the adopted treatment. Relationships to other taxa in the genus are also discussed, and the new combination X. rutherfordii (Mart. Rodr., P. Vargas, M. Carine & Jury) Mart. Rodr. & M. B. Crespo comb. nov. is provided.  相似文献   

6.
The New World tetraploid cottons, G. hirsutum and G. barbadense, are natural amphidiploids (genome formula, 2[AD]) combining species of the cultivated Asiatic (2A) and wild American (2D) groups of diploid cottons. Multivalent frequency, per cell, for 2 New World X Asiatic synthetic hexaploids, G. hirsutum X G. arboreum and G. barbadense X G. arboreum, is 6.68 and 7.80, respectively. Multivalents per cell for a series of New World X wild American synthetic hexaploids are: New World X G. harknessii, 3.65;— X G. armourianum, 3.96;— X G. aridum, 3.48;— X G. lobatum, 3.66; — X G. gossypioides, 1.13. The expected correlation between multivalent frequency and genetic segregation (e.g., high multivalent frequency = high recovery of recessives, and vice versa) for these hexaploids is realized for the near-allopolyploids (New World X wild American) but only approximated for the near-autopolyploid combinations, New World X Asiatic. This is explained on the basis that different homogenetic:heterogenetic bivalent ratios are expected in autopolyploids as compared to allopolyploids.  相似文献   

7.
8.
Summary Two new species of hystrignathid nematode are described from passalid beetles in Trinidad, West Indies. Hystrignathus ferox n.sp., from the mid-gut caeca of Verres furcilabris (Esch.) is easily differentiated from H. rugosus Travassos & Kloss, 1958 and H. rescens Travassos & Kloss, 1958 on the character of the lateral alae. In H. rugosus the alae extend to the anus and in H. rescens to the vulva whereas in H. ferox n.sp. the alae are much shorter and terminate about two body-widths anterior to the vulva. Xyo xiphacanthus n.sp., from the mid-gut caeca of Veturius transversus var. trituberculatus (Esch.), is characterized by the cervical spines extending about an oesophagus length posterior to the basal bulb. No other nominal species of Xyo has the spines extending so far posteriorly. X. histrix Cobb, 1898 and X. histrix sensu Christie, 1934 are regarded as species inquirendae. Carlosia tijucana Travassos & Kloss, 1957 is illustrated and additional data provided. ac]19810415  相似文献   

9.
A new genus and species of heterotrophic dinoflagellate, Cryptoperidiniopsis brodyi gen. et sp. nov., are described. This new species commonly occurs in estuaries from Florida to Maryland, and is often associated with Pfiesteria piscicida Steidinger et Burkholder, Pseudopfiesteria shumwayae (Glasgow et Burkholder) Litaker et al., and Karlodinium veneficum (Ballantine) J. Larsen, as well as other small (<20 μm) heterotrophic and mixotrophic dinoflagellates. C. brodyi gen. et sp. nov. feeds myzocytotically on pigmented microalgae and other microorganisms. The genus and species have the enhanced Kofoidian plate formula of Po, cp, X, 5′, 0a, 6″, 6c, PC, 5+s, 5″′, 0p, and 2″″ and are assigned to the order Peridiniales and the family Pfiesteriaceae. Because the Pfiesteriaceae comprise small species and are difficult to differentiate by light microscopy, C. brodyi gen. et sp. nov. can be easily misidentified.  相似文献   

10.
By backcrossing hybrids from the cross Drosophila mojavensis female × Drosophila arizonensis male to both parental species we show that several interspecific combinations of autosomes with one or the other sex chromosome (X or Y) result in sperm abnormalities. Two of these incompatibilities will cause the same type of nonreciprocal F1 male sterility that is observed in this pair of species, but the possibility of an additional incompatibility that would have the same result, e.g., an incompatibility between the mojavensis Y and the arizonensis X chromosomes, cannot be excluded. The incompatibility between the arizonensis Y chromosome and the mojavensis fourth chromosome found to occur for all tested populations of mojavensis race B (Vigneault and Zouros, 1986) is shown also to occur for race A of this species. We further show that a dominance relationship exists between heterospecific homologous autosomes in their interactions with the sex chromosomes and that the direction of the dominance depends on whether the sex chromosome is the X or the Y. The present role of these incompatibilities in preventing gene flow between the two species may be minor, but their genetic basis and mode of action may provide useful insights about the genetic events that have played a significant role in earlier stages of speciation.  相似文献   

11.
采用经典分类学研究方法,对河北师范大学植物标本馆(HBNU)等国内多个标本馆保存的中国丝瓜藓属直蒴组(Pohlia Hedw.section Cacodon Lindb.ex Broth.)及其近缘类群植物标本共计130余号进行了分类学分析鉴定,并对所确定的中国产直蒴组物种的芽胞大小、形状及叶原基数量和长度等形态学特征进行比较分析,以期为中国丝瓜藓属直蒴组的分类学研究提供理论依据。结果表明:(1)经鉴定中国丝瓜藓属直蒴组植物共有8种——夭命丝瓜藓[Pohlia annotina(Hedw.)Lindb.]、糙枝丝瓜藓[P.camptotrachela(Ren.Card.)Broth.]、林地丝瓜藓[P.drummondii(Müll.Hal.)Andr.]、疣齿丝瓜藓[P.flexuosa Harv.]、纤毛丝瓜藓[P.hisae T.J.Kop.et J.X.Luo]、异芽丝瓜藓[P.leucostoma(BoschSande Lac.)M.Fleisch.]、念珠丝瓜藓[P.lutescens(Limpr.)H.Lindb.]和卵蒴丝瓜藓[P.proligera(Kindb.ex Breidl.)Lindb.ex Arnell]。(2)中国丝瓜藓属直蒴组植物的重要鉴别特征是在假根或叶腋处生有芽胞,而且芽胞形状以及叶原基形状和数量在直蒴组中存在差异,如念珠丝瓜藓具有假根生芽胞,而疣齿丝瓜藓具有两型芽胞。(3)对所鉴定的中国丝瓜藓属直蒴组8种植物的识别特征、生境及其与相近种的关系进行了详细描述,并绘制了形态特征墨线图。  相似文献   

12.
This study is focused on a poorly known genus of small killifishes, Xenurolebias, comprising species uniquely living in temporary pools of the Atlantic Forest in the coastal plains of eastern Brazil (a region undergoing intense deforestation). Xenurolebias comprises two nominal, morphologically similar species, but some variability among populations suggests it represents a species complex. In order to delineate species limits, a taxonomic revision was conducted combining two different approaches: (i) a character-based approach using morphological variation (colour patterns, fin morphology, meristic and morphometric data) and (ii) a tree-based approach using mt-DNA (tRNA-Met, tRNA-Gln and ND2). The results strongly supported four species: X. myersi (Carvalho) from the Itaúnas river basin and adjacent smaller drainages; X. izecksohni (Cruz) from the Barra Seca river basin; X. cricarensis Costa, sp. nov., from the São Mateus river basin; and X. pataxo Costa, sp. nov., from the Mucuri, Itanhem and Jucuruçu river basins. Recognition of four distinct species in Xenurolebias should change views about the conservation of the species, one of which (X. pataxo) is seriously endangered and should be considered a priority for conservation.http://zoobank.org/urn:lsid:zoobank.org:pub:8485DD00-3F30-4C9F-9682-62C4718D53D9  相似文献   

13.
One species of Tyzzeria and 4 new species of Eimeria are described from the Ceylon jungle fowl Gallus lafayettei. The sporulated oocysts of Tyzzeria galli sp. n. are 13.8 (12–15) μ m; of Eimeria lafayettei sp. n., 19.5 (19–21) X 14.2 (13.5–15) μ m; of Eimeria indentata sp. n., 30.3 (29.5–32) X 21.4 (20–22) μ m; of Eimeria symmetrica sp. n., 35 × 28.5 μ m, and of Eimeria dissanaikei sp. n., 21 (19–23) X 14 (12–16) μ m. E. indentata, E. symmetrica, and E. dissanaikei produced patent infections in domestic fowl but T. galli and E. lafayettei did not. This is the 1st record of the genus Tyzzeria from the order Galliformes.  相似文献   

14.
Haplodontium zangii X.R.Wang &; J.C.Zhao, a new moss species from Xizang, China, is described and illustrated. Previously, specimens of H. zangii have been identified as Mielichhoferia himalayana Mitt. However, H. zangii is distinctly different from M. himalayana in having excurrent costae with short awns (vs long denticulate awns), short-pyriform capsules, 0.8–1?mm (vs long-pyriform capsules, 2.5–3?mm), and densely papillose exostome teeth (vs smooth or vertically striped exostome teeth). Haplodontium zangii is similar to H. macrocarpum (Hook.) J.R.Spence, which was traditionally placed in Mielichhoferia Nees &; Hornsch. as M. macrocarpa (Hook.) Bruch &; Schimp. The main differences between H. zangii and H. macrocarpum are in the morphology of the leaves, capsules, guide cells, and stomata. Mielichhoferia himalayana and another Chinese species of Mielichhoferia, M. sinensis Dix., are also transferred to Haplodontium Hampe, a new genus in the bryoflora of China, as H. himalayanum (Mitt.) X.R.Wang &; J.C.Zhao and H. sinensis (Dix.) X.R.Wang &; J.C.Zhao. A morphological comparison and a key to the three species of Haplodontium in China as well as to H. macrocarpum, a species that is likely to be found in China, are provided.  相似文献   

15.
Ferula paeoniifolia X. G. Ma & C. Y. Liao sp. nov., from Sichuan Province, Southwest China, is described and illustrated. The new species is most similar to F. kingdon‐wardii Wolff in morphology, but differs significantly in its ternate‐2‐pinnate compound leaves with much broader leaflets. The key morphological characteristics and nuclear ribosomal internal transcribed spacer (ITS) region were also compared between F. paeoniifolia and its relatives.  相似文献   

16.
Heavy metal accumulation in crops and soils from wastewater irrigation poses a significant threat to the human health. A study was carried out to investigate the removal potential of heavy metals (HM) by native plant species, namely Cannabis sativa L., Chenopodium album L., Datura stramonium L., Sonchus asper L., Amaranthus viridus L., Oenothera rosea (LHer), Xanthium stramonium L., Polygonum macalosa L., Nasturtium officinale L. and Conyza canadensis L. growing at the municipal wastewater site in Abbottabad city, Pakistan. The HM concentrations varied among plants depending on the species. Metal concentrations across species varied in the order iron (Fe) > zinc (Zn) > chromium (Cr) > nickel (Ni) > cadmium (Cd). Majority of the species accumulated more HM in roots than shoots. Among species, the concentrations (both in roots and shoots) were in the order C. sativa > C. album > X. stramonium > C. canadensis > A. viridus > N. officinale > P. macalosa > D. stramonium > S. asper > O. rosea. No species was identified as a hyperaccumulator. All species exhibited a translocation factor (TF) less than 1. Species like C. sativa, C. album and X. stramonium gave higher (> 1) biological concentration factor (BCF) and biological accumulation coefficient (BAC) especially for Fe, Cr and Cd than other species. Higher accumulation of heavy metals in these plant species signifies the general application of these species for phytostabilization and phytoextraction of HM from polluted soils.  相似文献   

17.
Zingiber pauciflorum L.Bai, ?korni?k., D.Z.Li & N.H.Xia (Zingibereae, Zingiberaceae), a new species from southern Yunnan, China, is described and colour plates are provided. It belongs to Z . sect. Cryptanthium Horan. and is compared with three similar species, namely Z. tenuifolium L.Bai, ?korni?k. & N.H.Xia, Z. smilesianum Craib and Z. yunnanense S.Q.Tong & X.Z.Liu. A colour plate of the most similar species, Z. smilesianum is also provided for comparison.  相似文献   

18.
New chromosome counts are reported for four African diploid species of Hibiscus L. sect. Furcaria DC: H. greenwayi Bak. f., H. hiernianus Exell et Mendonça, and H. mechowii Garcke, n = 18; and H. berberidifolius A. Rich., 2n = 36. Chromosome behavior is described in seven new hybrid combinations. Hibiscus greenwayi is shown to carry an A genome. Hibiscus hiernianus and H. mastersianus have similar genomes which are not homologous with that of H. mechowii. New and earlier data are integrated to elucidate genome relationships among 13 taxa–each of the four tetraploid species has a different formula encompassing 2 of 6 mutually nonhomologous genomes, A, B, G, H, X and Y (H. acetosella Welw. ex Hiern = AABB; H. meeusei Exell = AAXX; H. sabdariffa L. = AAYY; H. rostellatus Guill. et Perr. = GGHH). Diploid donors of A, B, G, X and Y are proposed on the basis of plant, flower and pollen morphology. Diploid carriers of A (H. asper Hook. f., H. cannabinus L., H. greenwayi), B (H. surattensis L.) and G (H. sudanensis Hochr.) have been verified cytologically. Cytological confirmation of X (H. hiernianus, H. mastersianus Hiern) and Y (H. mechowii) carriers is incomplete. No putative diploid carrier of H is at hand. Genome affinities of H. berberidifolius are unknown.  相似文献   

19.
Relative amounts of nuclear DNA were determined in root tip cells of seven species of Astereae: Aster hydrophilus Greene, A. oblongifolius Nutt., A. riparius H.B.K., Machaeranthera boltoniae (Greene) Turner and Home, M. brevilingulata (Sch-Bip.) Turner and Home, M. parviflora Gray, and M. tenuis (S. Wats.) Turner and Home. The results show that A. hydrophilus and M. brevilingulata, with a chromosome number of n = 9, have less nuclear DNA than other closely related species which are either n = 4 or n = 5. Cytological analyses of meiosis in the intergeneric hybrid M. parviflora X A. hydrophilus showed cells with two or more small chromosomes of the latter species pairing with single large chromosomes of the former. Pachytene cells of the hybrids M. parviflora X A. hydrophilus, M. parviflora X A. riparius, and M. boltoniae X M. tenuis showed some unpaired chromosome segments. The significance of these results to chromosome evolution in the tribe Astereae is discussed.  相似文献   

20.
The species of the genus Xiphinema Cobb, 1913 are listed and their current status is indicated. A revised polytomous key to the 172 valid species (excluding the X. americanum-group) is presented. Because of the very large number of species the key is split into eight groups on the basis of development of the anterior female genital branch, uterine differentiation and tail shape. In accordance with the opinion of Cohn & Sher (1972) X. vulgare Tarjan, 1964 is considered a synonym of X. setariae Luc, 1968. X. cubense Razzhivin, 1973 is placed in species inquirendae. Longidorella chappuisi (Schneider, 1935) is transferred to Xiphinema and its possible identity with X. hygrophilum Southey & Luc, 1974 is discussed.  相似文献   

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