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1.
Chromosome banding techniques (Giemsa and fluorochrome staining) were used to investigate Ornithogalum umbellatum L., O. angustifolium Bor. and 11 related taxa. Nine different basic Q-banding patterns, referred to as genomes, could be recognised. These patterns are indicated by capitals (A–E, P–S). Six of the nine basic genome types can be subdivided into different subtypes. The B genome was found in the two bulbilliferous species, i.e. O. umbellatum and O. angustifolium. It occurs in a number of combinations together with the A, C, D and E genomes. Genome combinations of these five basic types were found in seven species. Six of them share morphological characteristics. These species are: O. monticolum Jord. & Fourr., O. baeticum Boiss., O. angustifolium, O. refractum, Kit., O. umbellatum and O. algeriense Jord. & Fourr. A seventh species, O. platyphyllum Boiss., in which the E genome occurs, can be regarded as an intermediate between this complex and the O. montanum group. Each species is treated extensively; its morphology, geographical distribution, chromosome number and banding patterns are discussed separately. A model of the probable course of the evolution in this complex during the last two glaciation periods is described. In this model attention is paid to ecological differentiation, migration leading to the present distribution patterns, hybridization followed by polyploidization and to fixation, which may be the result of chromosomal rearrangements that prevent regular meiosis. Some cytotypes, formerly regarded as O. umbellatum, are now classified in other species. A second polyploid complex in which these species occur, is probably more widely distributed in south-eastern Europe than is generally thought at present. The species O. exscapum Ten., O. nivale Boiss., O. comosum L., O. collinum Guss. and O. gussonei Ten. p.p. are components of this complex. The delimitation of this complex as a whole and the relationship between its diploid and polyploid components have still to be clarified.  相似文献   

2.
Evolutionary relationships and infra- and interspecific variability within the species ofTulipa sect.Eriostemones Boissier were studied. Measurements of 35 morphological characters were used for principal component and canonical variate analyses. Crossing experiments and chromosome counts were carried out. Two axes of morphological variation were encountered within the principal component plot. Variation of subsect.Biflores was traced along one axis, the species of subsect.Australes as well asSaxatiles were found along the other axis. The nomenclature of names of subsect.Biflores was considered on the basis of their geography, specific morphological characteristics and polyploidy. Conspecificity of names of all species was tested based on both morphology and crossability.  相似文献   

3.
The following taxa are represented in East Africa (Kenya, Tanzania, Uganda): Ornithogalum donaldsonii (Rendle) Greenway (2n=20), O. gracillimum R. E. Fries, O. tenuifolium Delaroche ssp. sordidum (Bak.) Stedje comb. nov. (2n=16), and O. tenuifolium Delaroche ssp. robustum Stedje ssp. nov. (2n = 12).  相似文献   

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6.
Adenophora is an extremely variable genus,and its taxonomy is very controversial.Of the genus,Adenophora potaninii complex,including A.potaninii,A.bockiana,A.wawreana,A.lobophylla,A.biformifolia,A,polydentata,and A.wawreana var.lanceifolia,is a typical group with different taxonomical treatments due to high level of morphological diversity.We carried out extensive biosystematic studies based on population sampling,transplantation experiments and offspring tests,cluster analysis,and a crossing experiment.The results reveal four main findings.(i) Leaf forms of the A.potaninii complex were extremely polymorphic; the leaf form of A.potaninii and A.bockiana,and that ofA.wawreana and A.biformifolia could be found,respectively,on a single population or among the offsprings of a single plant.(ii) Cluster analysis and a crossing experiment indicated that A.bockiana and A.polydentata could not be separated from A.potaninii,nor d.biformifolia from A.wawreana.(iii) Adenophora potaninii and A.wawreana were gradational in morphology and their compatibility value was slightly reduced compared to that within each entity.(iv) Adenophora lobophylla was distinct from the other members of the complex in shape and size of corolla,relative length of style,and shape of capsule.This species was incompatible reproductively with the other members of the complex,but partly compatible with A.stenanthina,a species in another section.Therefore,we recognized only one species with two subspecies in the complex,A.potaninii subsp.potaninii and subsp,wawreana,moved A.lobophylla out of the complex,and reduced all the other names as new synonyms.  相似文献   

7.
Meiotic behaviors and reproductive modes of Japanese Isoetes were studied. The hexaploid (2n = 66) and the octaploid (2n = 88) of I. japonica consistently formed 33 and 44 bivalents, respectively, at diakinesis and/or metaphase I in both micro- and megaspore mother cells. The tetraploid (2n = 44) of I. sinensis formed 22 bivalents and its hexaploid made 33 bivalents in both types of spore mother cells. At diakinesis and/or metaphase I of microspore mother cells in I. asiatica with 2n = 22, 11 bivalents were detected. Because behaviors of meiosis in all cytotypes mentioned above were quite regular and plants yielded normal-appearing spores, they should reproduce sexually. Aneuploids of I. japonica with 2n = 87 formed 43 bivalents and one univalent, and I. sinensis with 2n = 65 formed 32 bivalents and one univalent in microspore mother cells. Meiosis of both cytotypes was almost regular and yielded microspores of normal appearance. In the heptaploid (2n = 77) of I. japonica, a configuration of 22 bivalents and 33 univalents was detected in micro- and megaspore mother cells, and various irregularities were observed throughout the meiotic divisions. Therefore, the genomic formula of the heptaploid is symbolized as AABBCDE, and the heptaploid is a sterile F, hybrid between the hexaploid (AABBCC) and the octaploid (AABBDDEE) of I. japonica. Since diploid and even-numbered polyploids regularly formed bivalents and odd-numbered ones displayed irregularities, allopolyploidy should act as a significant speciation mechanism in this genus.  相似文献   

8.
Populations of the genus Philaenus were collected during the last 12 years at several places in Greece ranging in altitude from sea level to 2000 m. Within some of these populations the species P. spumarius (Linnaeus, 1758), which is widely distributed in Greece, and the Mediterranean species P. signatus (Melichar, 1896) occurred together. These two species can be easily distinguished by the size of the adults, and more precisely by internal genital structures. Surprisingly, some mountainous populations of P. spumarius also contained a new species. Externally the new species closely resembled P. spumarius , but careful examination of the male genitalia provided clear identification characteristics. The new species comprised one bisexual common colour morph similar to populi of P. spumarius and P. signatus and two rare unisexual morphs which are lacking both in P. spumarius and P. signatus. The new species occurred only at altitudes above 1200 m on Eryngium spp. (Umbelliferae) between June and August.  相似文献   

9.
Qualitative and quantitative characteristics of mega- and microspores from all the cytotypes of JapaneseIsoetes are described based on the voucher specimens whose chromosome numbers were known. InI. japonica, the hexaploid possessed reticulate megaspores and levigate microspores, while the octaploid and the heptaploid had echinate microspores. Mega- and microspores of the hexaploid and the octaploid were of normal appearance, while those of the heptaploid displayed polymorphism. The tetraploid and the hexaploid ofI. sinensis resembled each other, since they both possessed cristate megaspores and echinate microspores. Echinate megaspores and levigate microspores characterized the diploidI. asiatica. The spore size was largely variable within each cytotype, while the size of the megaspores varied more than that of the microspores. The microspore length was closely correlated with polyploid level. InI. sinensis, the mean microspore length of the tetraploid was 27.6 μm while that of the hexaploid was 31.9 μm, hence these two cytotypes were easily distinguishable. In the hexaploidI. japonica, variations in mega-and microspore size displayed geoclinal variation showing a positive correlation (r=0.43–0.55) with the longitude and the latitude of the populations. A palynological key for cytotypes is presented.  相似文献   

10.
An account is given of the morphology and taxonomy of the African genus Ornithoglossum Salisb. The genus belongs to the Liliaceae–Wurmbeoideae, a phytochemi–cally distinct taxon sometimes treated as a separate family, the Colchicaceae. Ornithoglossum belongs to the tribe Iphigenieae, which is here amended to include the former tribe Glorioseae. Within the genus Ornithoglossum 8 species are here recognized, 3 of which are new, viz. O. parviflorum B. Nord., O. vulgare B. Nord. and O. gracile B. Nord. Two varieties of O. parviflorum are recognized. O. zeyheri (Baker) B. Nord. is a new combination. The chromosome number 2n = 24 is recorded for four species. The genus is believed to have originated in formerly arid regions of tropical Africa. Because of a climatic change, an increase in humidity, a south– and southwestward migration took place, followed by speciation in response to factors in the new environment. Sympatric speciation may have been promoted by the development of differences in flowering times and by specialization to different pollinators. The evolution of the nectary region of the tepals is particularly illuminating, and taxonomically useful. The proposed taxonomy is further supported by ultrastructural features of the seeds and pollen grains.  相似文献   

11.
VAN RAAMSDONK, L. W. D. & DE VRIES, T. 1992. Biosystematic studies in Allium L. section Cepa. Principal component analyses and hybrid analyses, according to Wells, using 31 morphological characteristics were used to study the biosystematic relationships between six Allium species of section Cepa and A. roylei of section Rhizirideum. Seventeen interspecific hybrid populations were included. Based on these analyses and on additional information from geography, chromosome banding pattern, DNA amount and seed epidermis texture, the species of Allium section Cepa can be divided into three groups: 1. A. galanthum and A. pskemense , 2. A. cepa, A. oschaninii and A. vavilovii and 3. A. futulosum and A, allaicum. Presumed evolution of both groups 2 and 3 from the basic group 1 is indicated by the development of new morphological characteristics, a change in genome structure and migration.  相似文献   

12.
Abstract

A karyological analysis carried out in Scilla hyacinthoides L. and Scilla amoena L. on material collected in the Botanical Garden of Cagliari (Sardinia), has shown the presence of heterozygous karyotypes in the two species. The chromosome number of S. hyacinthoides was found to be 2n = 20, while the chromosome number of S. amoena was 2n = 12, in accordance with the data found in the literature. Both the observed karyotypes show clear structural alterations, especially evident in one pair of clearly heteromorphic chromosomes. The analysis of the karyotypes seem to exclude a hybrid origin of the material examined and it is probable that such karyotypes may be the result of various structural re-arrangements, still evolving and aiming at a cytogenetic stabilization of the genus Scilla.  相似文献   

13.
Representative specimens of the EuropeanGladiolus species (excl.G. palustris) were used to study variability and relationships. 25 characters were measured for cluster, principal component and Wells hybrid analyses (Figs. 1–3). Three (with PCA) respective five (cluster analysis) main groups are revealed. Bulb characteristics appear to be very useful for indentification. The subspecific status ofG. communis subsp.byzantinus is confirmed. Hybrids of four different parental combinations were detected in our collection. Most species include polyploid series. Partly 3x, 4x, 6x, 8x, 12x and aneuploid cytotypes but no diploids were found. Polyploids as pioneers and hybridization of sympatric species are apparently linked to migrations during the glacial periods.  相似文献   

14.
老鸦瓣群(Amana群)是百合科中的一个东亚特有类群,仅分布在中国中东部、日本和朝鲜半岛。该类群在形态上与广义郁金香属Tulipa L.相似,但也具有与子房近等长的花柱以及2-3(-4)个苞片等与郁金香属不同的形态特征。有关该类群是否应置于郁金香属中或是否应独立为属的问题长期以来存在争议。为了澄清该问题,我们对产于中国的Amana群进行了广泛的标本室和野外形态观察,并采用分支系统学方法,对该类群3个种以及郁金香属的其他15种植物(包括土耳其的3个种)的28个形态性状数据进行了分支分析。结果表明广义郁金香属并非是一个单系类群。Amana群与广义郁金香属的其他4个组sect. Orithyia、sect. Eriostemones、sect. Leiostemones、sect. Tulipanum以及Lloydia属的两个种共同构成一个大支的3个分支。我们对广义郁金香属5个组共19种植物的ITS以及trnL-F分子序列综合分析的结果也表明:sect. Tulipanum、sect. Leiostemones、sect. Eriostemones和sect. Orithyia构成一大支,Amana群和猪牙花属的Erythronium sibiricum构成另一大支。因此,我们认为Amana群应从广义郁金香属中独立出来,恢复其老鸦瓣属Amana Honda作为属的分类地位。  相似文献   

15.
Potentiometric studies on yeast complex III   总被引:3,自引:0,他引:3  
Potentiometric measurements have been performed on Complex III from bakers' yeast. The midpoint potentials for the b and c cytochromes were measured using room-temperature MCD and liquid-helium temperature EPR. A value of 270 mV was obtained for cytochrome c1, regardless of temperature, while the midpoint potentials found for the two species of cytochrome b varied with temperatures, viz., 62 and -20 mV at room temperature (MCD) compared to 116 and -4 mV at about 10 K (EPR). The midpoint potential of the iron-sulfur center obtained by low-temperature EPR was 286 mV. An abrupt conformational change occurred immediately after this center was fully reduced resulting in a change in EPR line shape. The potentials of the two half-reactions of ubiquinone were measured by following the semiquinone radical signal at 110 K and 23 degrees C. Potentials of 176 and 51 mV were found at low temperature, while values of 200 and 110 mV were observed at room temperature. The midpoint potential of cytochrome c1 was found to be pH independent. The potentials of cytochrome b were also independent of pH when titrations were performed in deoxycholate buffers, while a variation of -30 mV per pH unit was observed for both cytochrome c species in taurocholate buffers. These two detergents also produced different MCD contributions of the two b cytochromes. A decrease in Em of greater than 300 mV was found in potentiometric measurements of cytochrome c1 at high ratios of dye to Complex III. Antimycin does not affect the redox potentials of cytochrome c1 but appears to induce a transition of the low-potential b heme to a high-potential species. This transition is mediated by ubiquinone.  相似文献   

16.
A yellow-leaved plastome mutant of Hosta (Hosta sieboldii Ingram complex, Liliaceae) known as Wogan Gold lacks normal granal stacks, but has numerous stroma lamellae extending throughout the chloroplast. The chlorophyll a/b ratio is 0.76 in the mutant and 2.9 in wild type. The mutant contains a qualitatively normal pattern of other photosynthetic co-pigments. SDS-polyacrylamide gel electrophoresis showed a deficiency in the photosystem (PS) II light-harvesting complex. Since PS II is localized mainly in the granal region, the absence of the light-harvesting complex may explain the loss of granal stacking in this mutant.Abbreviation PS photosystem  相似文献   

17.
A morphological phylogenetic hypothesis of the relationships among the species of Africana is provided. The phylogenetic analysis suggests that Squamata or Amphibia were ancestral hosts for species of Africana, with dispersal events to Testudinidae; a second transfer to amphibians is also suggested. On the basis of biological data for these parasites and the paleogeographic reconstructions, a South American origin for Africana spp. is indicated, with subsequent dispersal events to Africa. It is further proposed that Chamaleonidae acquired species of Africana after their 'out-of-Madagascar' dispersal events to Africa.  相似文献   

18.
Based on a series of collections made in New Zealand it is concluded that Nephroselmis longifilis and Bipedinomonas pyriformis are identical species, for which the correct name is Nephroselmis pyriformis (N. Carter) comb. nov. A detailed examination by light and electron microscopy is given, using material from geographically widely separated areas, including Greenland, the North Sea, a shallow Danish Fiord, Thailand and New Zealand. N. pyriformis is a temperature– and halotolerant species, as shown by its known range of occurrence at temperatures from 2.3°C (West Greenland) to ca. 28°C (Thailand) and at salinities between 3 and 36%o. Features of fine structural interest include details of the scaly covering on the flagellar and cell surfaces, the former very similar to those on the flagella of Tetraselmis cordiformis , a quadriflagellate prasinophyte. Within the cell, the pyrenoid shows an unusual fine structure, being penetrated by a number of membrane–lined pockets, in which the membranes are continuous with thylakoids. N. pyriformis is compared with other members of the genus, and a list of the few known species is included.  相似文献   

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20.
Two forms of sympatric mice are captured in North - Tunisia: long - tailed mouse and short - tailed mouse. They are often considered as two semi - species of genus Mus, respectively Mus musculus musculus et Mus musculus spretus. They have the same Karyotype (2n = acrocentrics). The electrophoretic study of total proteins, shows up genetics differences. These two forms of mice may be considered as two different species, as like as mices of Europe: Mus musculus at long-tailed and Mus spretus at short tailed.  相似文献   

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