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1.
Depending on the species, Cryptocoryne plants grow in different biotopes, viz. spring, river, dark forest, and tree-savanna. The species of Lagenandra are exclusively found in river biotopes. The chromosome numbers found in this study corroborate the numbers previously recorded. Some variation in respect to the morphology of the inflorescence of C. wendtii de Wit and L. ovata (L.) Thwaites is described. A map presenting the distribution of the of Cryptocoryne with their chromosome numbers is included.
The existing populations of Cryptocoryne on Sri Lanka should be protected from further exploitation by plant collectors.  相似文献   

2.
Fourteen species of Cryptocoryne are recognized from Borneo: C. ciliata found throughout tropical Asia, C. longicauda also found in Johore; C. zonata, C. grabowskii , and C. edithiae show distinct affinities to the C. cordata group from the Malay peninsula; the remaining species, endemic to Borneo, do not show any special, close relationship with species from other areas. The synonomy, distribution, chromosome numbers, and ecology are treated.  相似文献   

3.
For a study of hybridization in Alopecurus , chromosome numbers, karyotypes, meiotic chromosome behaviour and breeding systems have been investigated in six species. In addition to confirming many previous chromosome numbers, new triploid and tetraploid counts have been found in A. bulbosus , which have not previously been reported. The karyotypes of all species have a very similar morphology but there are differences in chromosome size which can be related to differences in nuclear DNA content. At meiosis the diploid species form bivalents, but one population of A. aequalis contains plants that regularly form a single quadrivalent which would appear to be interchange heterozygotes. The meiotic behaviour of the tetraploids suggests that A. pratensis is an allotetraploid and A. geniculatus an autotetraploid. All species appear to be allogamous, although some, such as A. myosuroides are obligate outbreeders resulting from the presence of a self-incompatibility system, outbreeding is promoted in others by differences in the time of maturity of stigmas and anthers.  相似文献   

4.
The chromosome numbers of 75 species belonging to the family Araceae have been determined. The numbers for 53 species are reported for the first time. One number differs from previous reports ( Aglaodorum ), and one number is corrected (Phymatarum). Within 15 genera ( Gymnostachys, Pothoidium, Alloschemone, Heteropsis, Holochlamys, Anaphyllopsis, Dracontioides, Pseudohydrosme, Montrichardia, Bucephalandra, Taccarum, Asterostigma, Gorgonidium, Spathantheum and Ulearum ) the chromosome numbers have not previously been determined. The total number of genera cytologically investigated is now 99 (c. 94%).
A great diversity in chromosome numbers as well as in chromosome size and constitution is found. The results are discussed in relation to the phylogeny and the previously published classifications of the family.
A total list of chromosome numbers counted (>700 species) in the Araceae is presented (Appendix).  相似文献   

5.
Cytological observations on eleven species of Ophioglossum revealed low gametic ( n ) chromosome numbers of 30, 34 and 60 in populations of O.eliminatum , contrasting with an earlier report of n = 90 in the same species. The rest of the species is based on n =120.Cytologically studied species of Ophioglossum exhibit a range of chromosome numbers from n = 30 in O.eliminatum to n =720 in O.reticulatum. The weighted highest common factor (HGF) from all the reported chromosome numbers in twelve species was found to be 30. This number is proposed as the palaeobasic chromosome number for the genuS. Reported chromosome numbers which are not multiples of 30 were subjected to sequential analysis, yielding three distinct ultimate base numbers, 4, 5 and 6, which can produce n = 30 in seven different ways. The neobasic number, n= 120, appears to have arisen through various combinations and permutations of these, theoretically 2401 routes; only a relatively few of these routes exist today, suggesting that extreme selection has been exerted against the majority, and further suggesting that Ophioglossum represents an evolutionary dead end through repeated cycles of polyploidy and is possibly at the verge of extinction. The stoichiometric model of evolution, which derives the various chromosome numbers possessed by the twelve species from the basic and ultimate basic chromosome numbers, is used to explain chromosomal evolution in the genus.  相似文献   

6.
This article documents the addition of 112 microsatellite marker loci and 24 pairs of single nucleotide polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Agelaius phoeniceus, Austrolittorina cincta, Circus cyaneus, Circus macrourus, Circus pygargus, Cryptocoryne × purpurea Ridl. nothovar. purpurea, Mya arenaria, Patagioenas squamosa, Prochilodus mariae, Scylla serrata and Scytalopus speluncae. These loci were cross-tested on the following species: Cryptocoryne × purpurea nothovar. purpurea, Cryptocoryne affinis, Cryptocoryne ciliata, Cryptocoryne cordata var. cordata, Cryptocoryne elliptica, Cryptocoryne griffithii, Cryptocoryne minima, Cryptocoryne nurii and Cryptocoryne schulzei. This article also documents the addition of 24 sequencing primer pairs and 24 allele-specific primers or probes for Aphis glycines.  相似文献   

7.
Chromosome numbers in African and Madagascan Loranthaceae and Viscaceae   总被引:3,自引:0,他引:3  
Eighty-five chromosome numbers representing about 63 species and 23 genera are reported for African and Madagascan Loranthaceae. The base chromosome number of all genera studied is χ= 9. This chromosome number also typifies all other Old World genera of the tribe Lorantheae, and thus supports the previously suggested thesis that the Asian and African Loranthaceae are relatively closely related. Seventy-six chromosome numbers, representing three genera ( Arceuthobium, Korthalsella, Viscum ) and 40 species are reported for African and Madagascan Viscaceae. Most of the data are for Viscum. The number χ= 14 is suggested as the base chromosome number for both Viscum and the family as a whole. The Madagascan Visca , however, have a modal chromosome number of χ= 13. Aneuploid chromosome numbers of χ= 12, 11 and 10 occur in Viscum at the north-south distributional extremes in southern Africa and Europe and, with the addition χ= 13, in all the species with eastward distributions in Madagascar, Asia and Australia. Polyploidy is rare in African and Madagascan members of both families, as is generally also true for other parts of the world where they have been studied. Translocation heterozygosity is reported for a number of species in Viscum.  相似文献   

8.
In this account chromosome numbers of 22 species and varieties from five genera of Commelinaceae occurring in Malawi are given. For 14 of them this is the first time their chromosome numbers have been reported. A wide range of chromosome numbers of 2n = 26 , 28, 30. 44. 52 and 60 is noted in Commelina.  相似文献   

9.
Sect. Calceolaria (= Aposecos) of Calceolaria (Scrophulariaceae) in NW South America is revised, and the other species of the section are briefly discussed. The section comprises annual herbs with somewhat succulent stems and leaf–blades that are usually pinnately dissected (pinnatifid). Four species are recognized in the investigated area, viz. C. mexicana, C. tenuis, C. tripartita , and C. chelidonioides , and their chromosome numbers are reported (2n = 32, 60, 64, and 60 respectively). The basic number in sect. Calceolaria is x = 8. Two new combinations are made, viz. C. mexicana ssp. prostrata (Kränzlin) Molau and C. mexicana ssp. perijensis (Pennell) Molau. The species of sect. Calceolaria are intersterile and facultatively autogamous, and each species comprises numerous pure lines, some of which may be morphologically discernible.
In the appendices, chromosome numbers are listed and the occurrence of elaiophores in all NW South American species of Calceolaria is indicated. The chromosome numbers of C. crenata ssp. australis, C. adenanthera, C. gossypina, C. semiconnata, C. stricta, C. sericea , and C. comosa (all 2n = 36) have not previously been reported. A revised key to the sections of Calceolaria in NW South America is also provided.  相似文献   

10.
The American genus Cuphea with ca. 260 species is extremely diverse with respect to chromosome number. Counts are now available for 78 species and/or varieties, or 29% of the genus. Included in this study are first reports for 15 taxa from Brazil, Cuba, Dominican Republic, Mexico, and Venezuela. Twenty-two different numbers are known for the genus, ranging from n = 6 to n = 54. The most common number in the primary center of species diversity in Brazil is n = 8, which is regarded as the base number of the genus. Two numbers are most common in the secondary center in Mexico, n = 10 and n = 12. Species with n = 14 or higher are considered to be of polyploid origin. Polyploids comprise 46% of the total species counted and appear in 9 of the 11 sections for which chromosome numbers have been reported. Aneuploid species comprise ca. 25% of the genus and are known from 7 of the 11 sections. The two subgenera are not characterized by different chromosome numbers or sequences of numbers. None of the 14 sections are circumscribed by a single chromosome number. Morphological and ecological variability in widespread, weedy species is correlated with differing chromosome numbers in some species whereas in others the chromosome number is stable. Summary of chromosome numbers by taxonomic section is presented. Section Euandra, centered in eastern Brazil, and the largest section of the genus, appears to be chromosomally most diverse. In section Trispermum, characterized by difficult, variable species with intermediate forms, two of the four species studied have polyploid races. Section Heterodon, endemic to Mexico and Central America and comprising most of the annual species of the genus, is best known chromosomally. Chromosome numbers have been counted for 25 of 28 species, and 12 different numbers are reported. The most advanced sections, Melvilla and Diploptychia, with numerous species occurring at higher altitudes, are characterized by high polyploids. Apomictic species occur in sect. Diploptycia. The cytoevolution of Cuphea is complex with frequent polyploid and aneuploid events apparently playing a significant role in speciation in both centers of diversity.  相似文献   

11.
国产红树林植物的染色体计数   总被引:7,自引:0,他引:7  
本文对12种国产红树林植物和红树科、海桑科中2种非红树林植物进行了染色体计数,其中7种为染色体新计数,补充了中国红树林植物染色体资料的缺乏。通过调查,确认我国红树林植物有44种,占世界种类总数的44.9%。  相似文献   

12.
中国西部高山8种龙胆属植物的染色体数目   总被引:1,自引:1,他引:0  
本文报道了我国西部高山上的8种龙胆属植物的染色体数目。其中宽筒龙胆的染色体数目为2n=48,提钟龙胆的染色体数目为2n=26,小齿龙胆和四数龙胆的染色体数目为2n=24,南山龙胆的染色体数目为2n=18,上述5种植物的染色体数目为首次报道,其余蓝玉簪龙胆的染色体数目为2n=24,线叶龙胆的染色体数目为2n=48,钻叶龙胆的染色体数目为2n=18。  相似文献   

13.
中国水韭属植物的染色体数目及其分类学意义   总被引:12,自引:1,他引:12  
利用细胞学方法观察统计了中国4种水韭属Isoestes植物的染色体数目。结果发现4个种的染色体基数均为x=11,其中高寒水韭I.hypsophila Hand.-Mazz.为2n=22,为首次报道;台湾水韭 I.taiwanensis DeVol为2n=22;中华水韭I.sinensis Palmer 2n=44为四倍体;而产于云南贵州一带并一直被当作是宽叶水韭I.japonica A.Br.的水韭属植物2n=22,与文献报道的宽叶水韭(2n=66,67,77,87,88,89)完全不同,应重新予以认识和评价。依据本文和其他相关的研究结果,对东亚水韭属植物进行了分类处理。  相似文献   

14.
We present a case of new phenotypic findings not previously reported associated with a partial deletion of chromosome 11 with a break point at 23q - (46,XY,del(11)(q23). Partial deletion of chromosome 11q was first described by Jacobsen et al(4). Forty-eight patients have been reported during the last 30 years, with variable break points between 11q11 and 11qter. New phenotypic findings in our patient with the associated 11q deletion are imperforate anus, bilateral cataracts, and hypoplastic, multilobed lungs.  相似文献   

15.
Chromosome numbers are reported for 156 collections representing 100 taxa of Umbelliferae. Approximately two thirds of the collections are from Mexico, Central and South America and indicate a high percentage of polyploid species in certain genera found in this area. Chromosome numbers for plants belonging to 78 taxa are published here for the first time, previously published chromosome numbers are verified for 18 taxa and chromosome numbers differing from those previously published are reported in seven instances. No chromosome counts have been previously published for nine of the genera included here. Further aneuploidy and polyploidy were found in Eryngium, and Lomatium columbianum has been found to be a high polyploid with 2n = 14x. Every chromosome count is referable to a cited herbarium specimen.  相似文献   

16.
The external morphology of the six species is considered in detail, special attention being given to the branching System, flower form and the type of seed dispersal, which has often been misunderstood and has parallels among basidiomycete Fungi. In addition petiole anatomy is described, all species being different, and unpublished chromosome counts by other workers are reported (including 2n = 128 for G. canariense , a number erroneously reported earlier for G. palmatum). Crossing experiments (partly carried out by Mr W. Jackson) are described; the only successful new interspecific cross was G. maderense x G. palmatum. It is concluded that the six species, some of which are large pachycaul herbs endemic to Madeira or the Canary Islands, form an advanced group, and their affinities are discussed. A survey of other species with the same seed-discharge mechanism, and of annual or biennial species, suggests that among the latter decrease in chromosome number has taken place along several different lines, and it is suggested that thèse lowered numbers have been combined by amphidiploidy to create new basic numbers in the genus. A formal taxonomic treatment of sections Anemonifolia and Ruberta includes observations on infraspecific variation. An appendix reports the chromosome number of G. cataractarum as 2n = 36.  相似文献   

17.
The present work reports the chromosome numbers of 30 species of 7 genera of Magnoliaceae in China. The chromosome numbers of Liridendron chinense, Magnolia officinalis, M. liliflora, Michelia rigo and M. champaca are consistent with those previously reported Magnolia denudata was reported 2n=114, but our result shows 2n= 76; M. grandiflora was reported 2n=112, 114, but here 2n=114. Chromosome numbers of the other 23 species are reported for the first time. Vouchers for experimental materials have been preserved in Herbarium of the Department of Biology, Nankai University, Tianjin.  相似文献   

18.
横断山区是中国柴胡属Bupleurum植物的分布中心。本文对横断山区6个种2变种进行了染色体记数报道,其中4个种2变种是首次报道。对横断山区的10个种4个变种、中国北方(河北和黑龙江)的3个种的nrDNA ITS进行测序,同时从GenBank里面下载同属的来自非洲和地中海西部的16个nrDNA ITS序列数据,结合染色体数目变化结果,初步探讨了横断山区柴胡属植物的系统发育。结果表明横断山区可能是现代柴胡属植物的频度中心和多样分布中心之一。它们的祖先种可能是非洲北部的木本柴胡属植物B.fruticosum,或者是地中海西部的柴胡属植物,推测是通过中东和高加索扩散而形成的,其中与非洲南部特有种B.mundtii的亲缘关系也较近;染色体基数演化趋势是:8是较原始基数,6和7是次生基数,其染色体异基数变异和多倍化可能是物种形成、进化以及向外扩散的主要方式;在ITS系统发育树中,中国柴胡属植物染色体基数为8的种类聚为一支,染色体基数为6和7的种类聚为了一支,不支持舒璞等(1998)关于中国柴胡属的属下分类系统。结合已有的形态学、细胞学、孢粉学证据和ITS系统发育树,建议窄竹叶柴胡B.marginatum var.stenophyllum独立成种。  相似文献   

19.
染色体数目和倍性是系统与进化生物学和遗传学研究中十分重要的基础信息。为探索半蒴苣苔属染色体制片的适宜条件以及染色体数目的进化模式及其与物种的进化关系,该研究基于半蒴苣苔属染色体数目的进化历史,并根据该属植物具有叶片扦插繁殖的特性,采用叶片水培生根法获取半蒴苣苔(Hemiboea subcapitata)、弄岗半蒴苣苔(H.longgangensis)、龙州半蒴苣苔(H.longzhouensis)、江西半蒴苣苔(H.subacaulis var.jiangxiensis)、华南半蒴苣苔(H.follicularis)和永福半蒴苣苔(H.yongfuensis)6种植物的根尖材料,分析不同实验条件对染色体制片效果的影响,对染色体制片实验的条件进行优化及染色体计数,结果表明:(1)9:30—10:00取材,解离10 min以及染色15 min为半蒴苣苔属染色体制片的适宜条件。(2)上述6种半蒴苣苔属植物均为二倍体,染色体数目均为32(2n=2x=32)。(3)除个别物种染色体数目有变化以外,该属大部分物种染色体数目可能为2n=2x=32且染色体数目变化可能是非整倍化的作用,与物种进化没有明...  相似文献   

20.
Chromosome numbers of 65 species of sect.Hoarea have been determined. These show three basic chromosome numbers, x = 11, 10 and 9. Only a few species are tetraploid. In five species both diploid and tetraploid cytotypes are reported. Several cases of deviations in chromosome numbers and cytological abnormalities were found, most of these being related to the presence of B chromosomes that occur in eight species. Evidence is presented to suggest that the basic chromosome numbers of x = 10 and x = 9 are derived from x = 11 by centric fusion. Although variation in basic chromosome number withinPelargonium has been the subject of detailed study, this is the first time that evidence has been found for a mechanism of change in basic number, that of centric fusion by Robertsonian translocation. For the species of sect.Hoarea with x = 9, where the evidence for Robertsonian translocation is greatest, this process has probably taken place quite recently. In contrast to results from other sections of the genusPelargonium, the three different basic numbers of sect.Hoarea do not contradict its delimitation as a natural taxon.  相似文献   

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