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1.
With the evidence from palynological, cytological, ecological and morphological data, the subspecific taxonomy of Asplenium trichomanes L. from China is carried out. Four subspecies and one variety, i.e.A. trichomanes L. ssp. trichomanes, A. trichomanes L. ssp. inexpectans Lovis, A. trichomanes L. ssp. quadrivalens D. E. Meyer emend. Lovis, A. trichomanes L. ssp. pachyrachis (Christ) Lovis et Reichst. and A. trichomanes L. var. harovii Moore emend. Midle are recognized from China. The distribution of each subspecies and variety is also presented. Some fragments of a type specimen named as A. trichomanes L. var. centrochinense Christ in PE are found to be different from the known taxa of A. trichomanes L. complex both morphologically andcytologically, and therefore are regarded representing a new species.  相似文献   

2.
3.
As a result of field work in Peru and Bolivia 1982–83, and herbarium studies, 21 new taxa are described and two new combinations are made in Calceolaria. The following species are described as new: C. sclerophylla, C. arbuscula , and C. crassa of sect. Sa–licifoliae; C. rupestris of sect. Revolutae; C. micans, C. laevis, C. rariflora , and C. concava of sect. Teucriifoliae; C. bullata and C. neglecta of sect. Parvifoliae; C. amoena and C. ramosa of sect. Polyclada; C. pilosa, C. incana, C. hirsuta , and C. cordifolia of sect. Urticopsis; C. cumbemayensis of sect. Lobatae; and C. caespitosa of sect. Scapiflorae. Three new subspecies are described: C. deflexa R. & P. ssp. cuneata and C. salicifolia R. & P. ssp. nigricans of sect. Salicifoliae , and C. hispida Benth. ssp. acaulis of sect. Lobatae. Two new combinations are proposed: C. melissifolia Benth. ssp. pseudoscabra (Edwin) Molau of sect. Teucriifoliae , and C. llamaensis (Edwin) Molau of sect. Anacyrta. The taxon Revolutae is raised to the sectional level, and the sections Polyclada and Parvifoliae are emendated. Chromosome numbers are reported for C. sclerophylla (2n = 36), C. micans (2n = 72), C. laevis (2n = 72), C. melissifolia ssp. pseudoscabra (2n = 36), C. neglecta (2n = 36), C. cumbemayensis (2n = 36), and C. hispida ssp. acaulis (2n = 36).  相似文献   

4.
The present paper reports karyotypes in 4 species and 5 subspecies of Hippophae L. in China. It is found that all of the species and subspecies are diploid, with 2n=24, their complements are made of m and sm chromosomes and of them only H. thibetana has a pair of satellites. All of these karyotypes are symmetrical and primitive. It can be simplied as follows: Hippophae neurocarpa 2n = 2x = 24 = 18m+6sm, H. thibetana 2n = 2x = 24 = 14m (2sat)+ 8sm, H. rhamnoides L. ssp. gyantsensis 2n=2x=24= 18m+ 6sm, H. salicifolia 2n = 2x = 24 = 10m + 14sm, H. rhamnoides L. ssp. sinensis 2n=2x= 24 = 18m + 6sm, H. rhamnoides L. ssp. turkestanica 2n = 2x = 24 = 20m + 4sm; Hi. rhamnoides L. ssp. yunnanensis 2n = 2x = 24 = 14 + 10sm, H. rhamnoides L. ssp. mongolica 2n = 2x = 24 = 16m + 8sm.  相似文献   

5.
The genetic structure of five populations of the tetraploid fern Asplenium trichomanes subsp. quadrivalens in northern Switzerland was analyzed. Asplenium trichomanes subsp. quadrivalens is one of the most common and most widespread ferns in Europe. In this study we have combined genetic investigations, spatial autocorrelation, and breeding experiments to investigate in detail five populations from natural rock faces. Enzyme electrophoresis revealed very low genetic variability within and among the populations. The small amount of variation was partitioned mainly among the localities, indicated by high Fst values up to 0.764. Overall means of the proportion of polymorphic loci (P=0.076), the mean number of alleles per locus (A=1.086), and the mean expected heterozygosity (H=0.018) were low compared with other ferns (e.g., Kirkpatrick et al. 1990). Very few heterozygous individuals were found. Values of the fixation index (F) were high, ranging between 0.732 and 1.000 and indicating substantial inbreeding. Spatial autocorrelation showed different patterns of substructure in populations of A. trichomanes subsp. quadrivalens with a tendency for patches in short distances (up to 1.5 m). The breeding experiments with isolated prothalli and prothalli pairs showed that a mean of 56.4% of the isolated prothalli were successful in sporophyte formation. The highest rate in one population was 83.3%. We conclude that genetic load must be low in A. trichomanes subsp. quadrivalens. Sporophyte formation was statistically more successful in the experiments with gametophyte pairs than in isolates, indicating that additional cross-fertilization occurred. The latter agreed with the occurrence of few heterozygote samples and the small number of multilocus phenotypes found in natural habitats. Asplenium trichomanes subsp. quadrivalens is shown to be a highly inbreeding taxon with the capability of single spore colonization and subsequent founding of new populations. Such features can be hypothesized to have contributed to the postglacial colonization and the widespread distribution of this taxon in Europe.  相似文献   

6.
A taxonomic revision of Psathyrostachys (Poaceae)   总被引:1,自引:0,他引:1  
  相似文献   

7.
Eight taxa are treated, viz. Hordeum pubiflorum ssp. pubiflorum (2n=14), ssp. halophilum (comb. nov.) (2n=14), H. comosum (2n=14), H. jubatum ssp. jubatum (2n = 28), H. jubatum ssp. intermedium (2n = 28), H. lechleri (2n=42), H. procerum (2n=42), and H. arizonicum (2n=42). Information about morphological variation, cytology, and genome relationship, ecology and distribution is presented.  相似文献   

8.
The karyotypes of eight wild Greek Paeonia taxa were studied, viz. P. clusii ssp. clusii (2n = 10, 20), P. clusii ssp. rhodia (2n = 10), P. mascula ssp. mascula (2n = 20), P. mascula ssp. hellenica (2n = 20), P. mascula ssp. icarica (2n = 20), P. mascula ssp. russi (2n = 10), P. peregrina (2n = 20) and P. parnassica (2n = 20). P. mascula and P. clusii have a very similar haploid chromosome complement, x = 5, including three metacentric chromosomes, one submetacentric and one subtelocentric. In the chromosome complements of the tetraploid P. peregrina and P. parnassica the same chromosome types are included but their karyotype differ from those of the former two species by a number of characters. The main karyotype differences are concerned with the size differentiation of the chromosomes which in the case of P. peregrina has resulted in the diploidization of the tetraploid karyotype.
From the individuals examined, six were found to have abnormal karyotypes suggesting chromosomal exchanges. These structural aberrations in which mainly submetacentric and subtelocentric chromosomes are involved have also been described and discussed.  相似文献   

9.
拟鹅观草属3种植物的核型研究   总被引:4,自引:0,他引:4  
对禾本科小麦族拟鹅观草属物种Pseudoroegneria geniculata、P.geniculata ssp.scythica和P.geniculata ssp.pruinifera的核型进行了研究.结果显示:P.geniculata和P.geniculata ssp.scythica为四倍体物种,P.geniculata ssp.pruinifera为六倍体物种;P.geniculata、P.geniculata ssp.scythica和P.geniculata ssp.pruinifera的核型公式分别为2n=4x=28=18m(2sat)+10sm(2sat)、2n=4x=28=28m(2sat)和2n=6x=42=36m(6sat)+6sm(2sat);P.geniculata和P.geniculata ssp.pruinifera为2A核型,而P.geniculata ssp.scythica为1A核型.研究表明:3种植物的核型存在差异;P.geniculata ssp.pruinifera的核型为首次报道,其核型明显不同于P.geniculata和P.geniculata ssp.scythica.  相似文献   

10.
荞麦起源于我国西南地区,该地区分布着丰富的荞麦野生种,剖析野生荞麦的核型特征对荞麦进化和育种研究具有重要的意义。本研究以甜荞近缘种、硬枝万年荞、疏穗小野荞、细柄野荞、齿翅野荞为试验材料,采用常规压片法进行核型鉴定。结果表明:甜荞近缘种、硬枝万年荞和疏穗小野荞都为二倍体,核型公式分别为2n=2x=16=12M+4m(2SAT)、2n=2x=16=16M、2n=2x=16=14M+2m(2SAT),而细柄野荞和齿翅野荞为四倍体,核型公式分别为2n=4x=32=32M、2n=4x=32=30M+2m(2SAT)。甜荞近缘种和硬枝万年荞核型属1A型,疏穗小野荞、细柄野荞和齿翅野荞核型属1B型,并且甜荞近缘种、疏穗小野荞和齿翅野荞都有1对随体染色体。研究证明,荞麦野生种染色体的基数为8,有二倍体和四倍体野生荞麦。通过比较分析,硬枝万年荞在进化地位上比较原始,齿翅野荞是比细柄野荞较进化的四倍体荞麦野生种。  相似文献   

11.
New chromosome number determinations are presented for 48 populations of five subspecies of Turnera sidoides. Chromosome counts in sspp. carnea, holosericea, integrifolia and sidoides confirm previous data while, in ssp. pinnatifida , the numbers 2n=2x = 14 and 2n = 6x = 42 are reported for the first time. The results show that polyploidy is a very frequent phenomenon. Populations are primarily tetraploids (2n = 4x = 28), while diploids (2n = 2x = 14), hexaploids (2n = 6x =42) and octoploids (2rc = 8x = 56) are less frequent. Diploid, tetraploid and hexaploid cytotypes occur in sspp. carnea and pinnatifida , whereas tetraploids and hexaploids are known in ssp. holosericea. Turnera sidoides ssp. integrifolia shows a polyploid series with ploidy levels from 2x to 8x. The ssp. sidoides appears to be uniformly tetraploid, with the exception of an isolated pentaploid (2rc = 5x = 35). On the basis of these counts and previous reports the geographical distribution of the cytotypes has been determined and related to climatic and ecological factors.  相似文献   

12.
Allozyme variation was studied in Swedish populations of Silene vulgaris (a widespread weed), S. uniflora ssp. uniflora (restricted to coastal habitats) and S. uniflora ssp. petraea (endemic to Sweden and confined to open limestone habitats). The taxa are diploid, gynodioecious, perennial herbs and showed high levels of within-taxon and within-population gene diversity at four polymorphic loci. Within-taxon diversity was highest (Htax=0.52) in S. vulgaris and lowest (Htax=0.36) in S. uniflora ssp. uniflora. The weedy S. vulgaris has more alleles than either of the other two taxa and 5 out of a total of 27 alleles are unique to S. vulgaris. Most of the gene diversity within each of the taxa is accounted for by within-population diversity. The between-population component of diversity is 10% in S. vulgaris , and 24% and 5%, respectively, in S. uniflora ssp. uniflora and ssp. petraea. Hybrids may occur between S. vulgaris and S. uniflora , but introgression is limited by the species' ecology. Neither allozyme nor distributional data support the suggestion that ssp. petraea is a recent hybrid between S. vulgaris and S. uniflora ssp. uniflora , although an older hybrid origin for ssp. petraea is possible. Patterns of allele frequency variation suggest that there has been some historical gene flow between taxa, outside their present areas of sympatry. It is likely that the two subspecies of S. uniflora , which occur in naturally open habitats, were able to colonize Sweden during the Late Glacial or early post-glacial, whereas S. vulgaris followed the spread of agriculture into Sweden.  相似文献   

13.
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   

14.
The following taxa of Drimiopsis (Hyacintheceae) are recognized for East Africa (Kenya, Tanzania, Uganda): D. barteri (2n=44), D. botryoides ssp. botryoides (2n=44, 55, 66), D. botryoides ssp. prostrata ssp. nov. (2n = 22), D. maculata and D . sp. A.  相似文献   

15.
A study of voles (Arvicolidae, Rodentia) from Gansu (China) designed to identify a potential host of Echinococcus multilocularis, responsible for human alveolar echinococcosis, leads to a general analysis of Microtus limnophilus population karyotypes, M1 of M. oeconomus populations from all of Eurasia and of M. limnophilus of Mongolia. The Microtus of Gansu belonging to the nominal subspecies M. limnophilus limnophilus (2n = 38; NF = 58) differs markedly in size and shape of M1 from the M. limnophilus of Mongolia, which must therefore be considered as a new subspecies M. limnophilus of malygini nov. ssp. (2n = 38; NF = 60) and the M. oeconomus of Mongolia should be ranked as M. oeconomus kharanurensis nov. ssp. (2n = 30; NF = 60).  相似文献   

16.
Physical mapping of the 5S and 45S rDNA in teosintes   总被引:1,自引:0,他引:1  
Han YH  Li LJ  Song YC  Li ZY  Xiong ZY  Li DY 《Hereditas》2002,137(1):16-19
The physical locations of the 5S and 45S rDNA sequences were examined in three types of teosinte, Zea mays ssp. mexicana (2n = 20), Zea diploperennis (2n = 20) and Zea perennis (2n = 40) by biotinylated fluorescence in situ hybridization (FISH). The tested materials only showed one hybridization site of 5S rDNA on their genomes, but they were different in the position of the signals. The hybridization site of Zea mays ssp. mexicana was located on the long arm of chromosome 2, indicating that it is the same as the cultivated maize in the position of 5S rDNA, while the sites of Zea diploperennis and Zea perennis were on the short arms of other chromosomes. For 45S rDNA, one hybridization site was detected at secondary constriction region of the satellite chromosomes in Zea mays ssp. mexicana and Zea diploperennis, while in Zea perennis, besides the site located at the secondary constriction region, a second site on the short arm of another chromosome pair was observed. Our results provide additional evidence for Zea mays ssp. mexicana being a subspecies of Zea mays.  相似文献   

17.
A tall allotetraploid member of the Dactylorhiza incarnata/maculata complex with unspotted leaves and large pinkish flowers from the island of Gotland in the Baltic was examined for molecular variation patterns at five nuclear microsatellite loci, nuclear ITS and in plastid haplotypes. The allotetraploid was well separated from allopatric allotetraploids of similar appearance, including the western European D. majalis ssp. integrata (syn. D. praetermissa) and forms of D. majalis ssp. lapponica from mainland Sweden. It also differed from other allotetraploids distributed in the Baltic Sea region, including D. majalis ssp. baltica and D. majalis ssp. lapponica. It is here recognized as D. majalis ssp. elatior (Fr.) Hedrén & H. A. Pedersen. Dactylorhiza osiliensis Pikner, described from Saaremaa (Estonia) is regarded as a synonym. The distribution covers Gotland, Saaremaa and possibly Hiiumaa. Dactylorhiza majalis ssp. elatior may have one or several recent origins within its present distribution area, and it contains no other molecular markers than those found in the parental D. incarnata var. incarnata and D. maculata ssp. fuchsii in the same area. It appears to have weak barriers towards secondary hybridization with its parental lineages. The situation is reminiscent to that of other young allotetraploids in the D. majalis s.l. complex, suggesting that introgression may be an underestimated process explaining the accumulation of genetic diversity in evolving allopolyploid plants.  相似文献   

18.
Mitotic chromosome numbers are reported from 35 vascular plant taxa endemic to the Balearic Islands that are poorly known cytogenetically. The chromosome numbers of Chaenorhinum rodriguezii (2 n  = 14), Coristospermum huteri (2 n  = 22), Carduus ibicensis (2 n  = 26), Filago petro-ianii (2 n  = 26), Ononis crispa ssp. zschackei (2 n  = 30), and Ophrys bertolonii ssp. balearica (2 n  = 36) were determined for the first time. New chromosome numbers are reported in Pimpinella bicknellii (2 n  = 22), Calamintha rouyana (2 n  = 46), Vicia bifoliolata (2 n  = 14), and Teucrium asiaticum (2 n  = 30). A new diploid cytotype (2 n  = 16) was found in Ranunculus paludosus ssp. barceloi , which is restricted to populations from the western Balearics (Eivissa and Formentera), whereas tetraploid plants are known from the eastern Balearics (Mallorca). It is suggested that the tetraploid cytotype arose from the diploid cytotype through autopolyploidy. The idiograms of Coristospermum huteri , Pastinaca lucida , Pimpinella bicknellii , Carduus ibicensis , Helianthemum scopulicolum , Helichrysum crassifolium , Vicia bifoliolata , p aeonia cambessedesii , Helleborus lividus , Ranunculus paludosus ssp. barceloi , and Linaria aeruginea ssp. pruinosa are determined for the first time.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 153 , 463–476.  相似文献   

19.
Z W Liu  R R Wang 《Génome》1993,36(1):102-111
To elucidate the genome constitutions of the tetraploid (2n = 4x = 28) species Elytrigia caespitosa, Lophopyrum nodosum, and Pseudoroegneria geniculata ssp. scythica and the hexaploid (2n = 6x = 42) Thinopyrum intermedium, meiotic pairing was studied in these species as well as 10 hybrids. Karyotype analysis with aceto-orcein stained root-tip cells was performed for the four species and the hybrids of T. bessarabicum with E. caespitosa, P. geniculata ssp. scythica, and T. intermedium. Karyotype analysis by Giemsa C-banding was carried out with the three tetraploid species and the two triploid hybrids involving T. bessarabicum. The species behaved as strict allopolyploids. All hybrids were male sterile with few stainable pollen grains. It is concluded from the results that the three tetraploid species have the genome formula JeJeSS and T. intermedium has the formula JeJeJeJeSS. The chromosomes of the Je and S genomes in these species had C-banding patterns differing from each other and from those of the extant diploid species. Based on these findings, the four species investigated should be placed in the same genus or the same section of a genus. However, new combinations are not proposed at this time pending future taxonomic investigation of the genome constitution of Elytrigia repens (L.) Nevski.  相似文献   

20.
The genus Zea is here divided into the Sect. Luxuriantes Doebley & litis sect. n., including the perennials Z. diploperennis (2n = 20) and Z. perennis (2n = 40) and the annual Z. luxurians (2n = 20); and Sect. Zea , including the wild Z. mays ssp.parviglumis and Z. mays ssp. mexicana (both 2n = 20), and Z. mays ssp. mays (2n = 20), the highly domesticated and tremendously variable derivate of the latter. This division is verified by a multivariate analysis of a large number of morphological characters of the male inflorescence. Cytogenetic and chemotaxonomic evidence supports the morphological conclusions. A consideration of the phylogeny of Zea within the conceptual framework offered by this new sectioning of the genus points convincingly to annual teosinte (Z. mays ssp. mexicana) as the ancestor of cultivated maize.  相似文献   

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