国产香茶菜属十三个分类群的细胞学研究

对国产11种2变种共16个居群的香茶菜属植物的染色体数目进行了研究。除线纹香茶菜细花变种以外,其它种类的染色体数目均为首次报道。研究结果表明,有12个物种为二倍体,其染色体数目均为2n=24,推测该属植物的染色体基数为x=12。而细锥香茶菜既有染色体数目为2n=24的居群,也存在2n=48的居群,表明该种为二倍体或四倍体,同时2n=48的染色体数目也是香茶菜属内的首次报道。     

A biosystematic study on polyploid populations of the genusSpiraea (Rosaceae) in Korea

A total of 61 chromosome counts from 11 taxa of Korean Spiraea was made. Our counts are the first report for eight taxa;S. blumei (2n=18, 36),S. chartacea (2n=36),S. chinensis (2n=36),S. fritschiana (2n=27, 36),S. microgyna (2n=18),S. prunifolia var.simpliciflora (2n=18),S. pseudocrenata (2n=36), andS. trichocarpa (2n=18). A new chromosome number of 2n=36 (tetraploid) is reported forS. pubescence. Populations of three species includingS. blumei, S. pubescence and .V.fritschiana, show different ploidy levels; diploid and tetraploid populations are found in the former two species and triploid and tetraploid ones, in latter species. Multiplication of chromosome numbers contributes to increase in size of pollen and stomata in the three species. Populations with different ploidy levels inS. blumei occupy different regions; diploid populations in inland Korea and tetraploid ones in Ullung Island. Island tetraploid population of 5.blumei might be originated from intra-island polyploidization through the introduction of diploid from inland Korea, considering the worldwide distribution of this species. Pollen fertilities of island populations of ,S′.blumei are relatively low, and sometimes no pollen grain is produced in anther sacs; it suggests that tetraploid population of the island is gynodioecious which may serve reduction of inbreeding depression.     

Taxonomic and evolutionary implications of intraspecific variability in chromosome numbers of species of Leucaena Benth. (Leguminosae)

Chromosome numbers were determined in 52 individuals of 14 taxa of Leucaena Benth. from 22 populations. For L. cuspidata and L. kmpirana these are the first published chromosome counts. Intraspecific variability was found for L. lempirana, L. macrophjlta and L. shanonii , and one diploid population of the tetraploid species L. pallida was identified. Comparison of our data with those in the literature showed that for L. collinsii and L. macrophylla there is a relationship between chromosome number and subspecies delimitation. The variability detected in chromosome numbers shows the complexity of the diploid and tetraploid species evolution, and suggests multiple origins for some of the polyploid taxa.     

Physical mapping of the 5S and 18S-25S rRNA genes by FISH as evidence that Arachis duranensis and A. ipaensis are the wild diploid progenitors of A. hypogaea (Leguminosae)

The 5S and the 18S-25S rRNA genes were physically mapped by fluorescent in situ hybridization (FISH) in all botanical varieties of cultivated peanut Arachis hypogaea (2n = 4x = 40), in the wild tetraploid A. monticola, and in seven wild diploid species considered as putative ancestors of the tetraploids. A detailed karyotype analysis including the FISH signals and the heterochromatic bands was carried out. Molecular cytogenetic landmarks are provided for the construction of a FISH-based karyotype in Arachis species. The size, number, and chromosome position of FISH signals and heterochromatic bands are similar in all A. hypogaea varieties and A. monticola, but vary among the diploid species. Genome constitution of the species is discussed and several chromosome homeologies are established. The bulk of the chromosome markers mapped, together with data on geographical distribution of the taxa, suggest that peanut originated upon domestication of A. monticola and evidence that the diploids A. duranensis and A. ipaensis are the most probable ancestors of both tetraploid species. Allopolyploidy could have arisen by a single event or, if by multiple events, always from the same diploid species.     

New or rare data on chromosome numbers in several taxa of the genus<Emphasis Type="Italic">Artemisia (Asteraceae)</Emphasis> in Poland

Chromosome counts in 16 populations of fiveArtemisia species from Poland are presented in this paper. Those ofA. annua (2n=18) andA. dracunculus (2n=90) are reported for the first time in Polish populations. The decaploid level (2n=90) is described for the first time in non-cultivated populations ofA. dracunculus, and several cases of aneusomaty (intraindividual aneuploid variations in chromosome number: 2n=87, 88 and 89) have been detected in this species. In addition to the already known diploid number (2n=18), the tetraploid level (2n=36) has been detected inA. absinthium. The same two numbers have been recorded inA. abrotanum, which represents the first tetraploid count in populations of this taxon occurring outside botanical gardens. Finally, the chromosome number ofArtemisia campestris subsp.sericea (tetraploid, 2n=36) is reported for the first time. The relevance of polyploidy for the evolution of the genus and other cytotaxonomic or cytobiogeographical aspects are briefly discussed.     

中国姜花属十九个分类群的细胞学研究

采用压片法对中国姜花属十八个分类群进行了体细胞染色体计数,对白姜花减数分裂终变期I的染色体数目和形态进行了观察。结果显示:包括白姜花在内的十九个分类群中有六个二倍体,一个三倍体,十二个四倍体,其中十二个分类群的体染色体数目为首次报道,显示中国姜花属植物具有较高比例的多倍体类型;姜花属的染色体基数为n=17,染色体组可能是多倍体起源的。     

Cytotaxonomy and breeding system of the genusBiscutella (Cruciferae)

Chromosome counts were determined for 46 populations ofBiscutella representing 28 taxa. The genus was found to contain diploid taxa with 2n = 12, 16 and 18, tetraploid taxa with 2n = 36 and hexaploid taxa having 2n = 54.B. laevigata L. s. l. consists of diploid and tetraploid populations which are poorly differentiated morphologically. TetraploidB. laevigata s. l. and hexaploidB. variegata Boiss. & Reuter (s. l.) are characterized by chromosomal instability. The variation in chromosome numbers and the occurrence of polyploidy is discussed in relation to the taxonomy of the genus. An investigation of the breeding system showed that most of the annual species were self-compatible and partly inbreeding and most of the perennial species self-incompatible and, therefore, outbreeding, while one annual species,B. cichoriifolia Loisel., showed both systems.     

CHROMOSOME NUMBERS OF CAMPANULACEAE. II. THE LOBELIA TUPA COMPLEX OF CHILE

Gametic chromosome numbers are reported for 27 collections representing the four species of the Lobelia tupa complex (Campanulaceae, Lobelioideae) in Chile; all are n = 21. This represents the first report of chromosome numbers for L. bridgesii Hook. & Arn., L. excelsa Bonpl., and L. polyphylla Hook. & Arn., and confirms previous reports of this number in L. tupa L. As the basic chromosome number of Lobelioideae is x = 7, these species are interpreted as hexaploids. Higher polyploids are extremely rare among Lobelioideae; most of those previously reported have been either sporadic individuals or populations within an otherwise diploid or tetraploid species, or occasional species within an otherwise diploid and tetraploid lineage. This is the first report of an entire complex of lobelioid species that is uniformly hexaploid. This suggests that the Chilean endemics are relatively derived within Lobelia, and offers some support for the monophyly of the complex.     

中国西南六种广义拂子茅属(禾本科)植物的染色体数目

广义拂子茅属（Calamagrostis）是一个世界温带广布的大属,有些作者又分为拂子茅属和野青茅属,但近期的研究表明处理为一个属较为合适。中国共有37种广义拂子茅属植物,但至今没有任何染色体的研究。本文报道了其中产于中国西南6种野青茅的染色体数目,其中Deyeuxia petelotii 4个居群,D．diffusa,D．moupinemis,D．nivicola和D．flvens各一个居群都是四倍体（2n=4x=28）,D．neglecta为六倍体（2n=6x=42）。根据广义拂子茅属植物染色体倍性特征,该属植物中至今未发现二倍体,四倍体是该属中倍性最低和最普遍的,广义拂子茅属的演化很可能是在四倍体的水平上进行的。由于以上几个四倍体种均是狭域分布的类群,所以可能是由四倍体的祖先隔离分化形成的。     

中国西南六种广义拂子茅属( 禾本科) 植物的染色体数目

广义拂子茅属( Calamagrostis) 是一个世界温带广布的大属, 有些作者又分为拂子茅属和野青茅属, 但近期的研究表明处理为一个属较为合适。中国共有37 种广义拂子茅属植物, 但至今没有任何染色体的研究。本文报道了其中产于中国西南6 种野青茅的染色体数目, 其中Deyeuxia petelotii 4 个居群, D1 diffusa, D1 moupinensis, D1 nivicola 和D1f lavens 各一个居群都是四倍体( 2n= 4x= 28) , D1 neglecta 为六倍体( 2n= 6x= 42) 。根据广义拂子茅属植物染色体倍性特征, 该属植物中至今未发现二倍体, 四倍体是该属中倍性最低和最普遍的, 广义拂子茅属的演化很可能是在四倍体的水平上进行的。由于以上几个四倍体种均是狭域分布的类群, 所以可能是由四倍体的祖先隔离分化形成的。     

Triploidy in Equisetum subgenus Hippochaete (Equisetaceae, Pteridophyta)

BACKGROUND AND AIMS: The genus Equisetum is cytologically uniform, having a base chromosome number of x = 108. All previously known species and hybrids that have been counted represent diploids with a sporophytic chromosome number of 2n = 216. Biosystematic studies on Equisetum subgenus Hippochaete revealed evidence that triploids occur in nature. The objective of this study was to confirm that triploid plants exist in the natural environment. METHODS: Flow cytometry was used to establish nuclear DNA values and cytological investigations of meiosis were carried out to obtain information on chromosome number and pairing behaviour. KEY RESULTS: Triploidy exists in three morphologically different hybrid taxa. Two of these are morphologically intermediate between a primary diploid hybrid and a parent, while the third apparently combines genomes from all three Central European Hippochaete species. Nuclear 1C DNA values for the four European Hippochaete species range from 21.4-31.6 pg. For the hybrids, the 1C DNA values not only occupy the same range as the species, but their total DNA amounts agree closely with values predicted by adding the 1C DNA values of each parental genome. Chromosome counts confirm diploidy in the species E. hyemale and E. variegatum and in the hybrid E. xtrachyodon (= E. hyemale x E. variegatum). For the triploids (2n approximately 324), cytological information is presented for the first time. CONCLUSIONS: Triploid taxa may have originated by backcrossing or by crossing of a diploid hybrid with an unrelated diploid species. As tetraploid plants are unknown, these crossings probably involve diploid gametophytes that developed from unreduced diplospores. By repeated crossing events or backcrossing, reticulate evolution patterns arise that are similar to those known for a number of ferns and fern allies.     

Observations on chromosome numbers and biosystematics in Dahlia (Asteraceae, Heliantheae) with an account on the identity of D. pinnata, D. rosea, and D. coccinea

The chromosome numbers in Dahlia (Asteraceae, Heliantheae) are surveyed, and counts made on species grown in the Botanic Garden, University of Copenhagen, are given. Next a biosystematic study of species within Dahlia sect. Dahlia is presented. It is concluded that taxa with the same chromosome number can be brought to hybridize without specific barriers (some diploids possibly excepted). Based on this conclusion, it is demonstrated that the original European introduction of dahlias from Mexico consisted of two tetraploid (2n = 64) hybrids and a native, diploid (2n = 32) D. coccinea with scarlet rays. One of the hybrids was named D. pinnara which designation is consequently not applicable for the native species, currently known under that name. Instead, the new designation D. sorensenii is formally established. The other hybrid, D. rosea , is a synonym of D. pinnara .     

New chromosome numbers for plant taxa endemic to the Balearic Islands

Mitotic chromosome numbers are reported from 25 vascular plant taxa, endemic to the Balearic Islands that are poorly known cytogenetically. The chromosome numbers ofAnthyllis vulneraria subsp.balearica (2n=12),Cymbalaria fragilis (2n=56), andPolygonum romanum subsp.balearicum (2n=40) were determined for the first time. A new chromosome number was found in several populations ofAnthyllis hystrix (2n=70) suggesting that this species is decaploid, in contrast to an earlier work reporting a higher ploidy level (2n=12x=84). The new chromosome number 2n=32 was reported inHypericum hircinum subsp.cambessedesii. It is suggested that the previous count (2n=40) could be explained by the presence of anomalous pentaploid cells in some tissues, contrating with the presence of a regular tetraploid complement (2n=32). Cytogenetic observations suggest thatSibthorpia africana has a diploid chromosome complement of 2n=18, with 0–2 accessory chromosomes. Accessory chromosomes are also reported forPhlomis italica, being the first record of B chromosomes in this genus. Chromosomal instability was found inGalium crespianum andG. friedichii species, with three numbers 2n=44, 55 and 66. Two cytotypes differing in ploidy level were documented within single plants. It is suggested that both species share a regular complement of 2n=44 and that the past hybridization events and formation of regenerating roots from the typical rootstock ofG. crespianum andG. friedrichii could be involved in the genesis of chromosome variants through partial endopolyploidy and concomitant somatic segregation.     

CYTOGEOGRAPHIC EVIDENCE FOR THE EVOLUTION OF DISTYLY FROM TRISTYLY IN THE NORTH AMERICAN SPECIES OF OXALIS SECTION IONOXALIS

A survey of haploid chromosome numbers of 18 North American taxa of Oxalis section Ionoxalis was initiated to determine the relationship between ploidal level, geographic distribution, and the occurrence of tristyly and distyly. Although chromosome numbers in the section are variable, the majority of tristylous populations are diploid. Among the distylous taxa a greater diversity of ploidal levels exists, with the higher chromosome numbers predominating. In section Ionoxalis the majority of the tristylous taxa are geographically restricted endemics of southern Mexico, while the distylous taxa have more extensive distributions ranging to the north. The association of diploidy and geographic endemism in the majority of the tristylous taxa suggests that these species are relictual. A few widespread tristylous taxa are polyploid, and often somewhat weedy. The probable derivation of widespread polyploid species from the restricted diploid endemics of southern Mexico appears to have been accompanied by the evolution of distyly from tristyly. The frequent association of polyploidy and distyly in section Ionoxalis has apparently resulted from the concurrence of two evolutionary trends: increase in ploidal level and the derivation of distyly from tristyly.     

Variation of Nuclear DNA Content in the Biflorus Species of Lonchocarpus (Leguminosae)

This represents the first study of nuclear DNA content in alarge sample (135 spp.) from a tropical arboreal genus, in whicha large proportion of the species were examined (42 spp., 31.1%).Somatic chromosome numbers and 4C-DNA values for 51 taxa ofLonchocarpus are reported. All taxa were diploid with 2 n =22,but their DNA content ranged from 1.92 to 2.86 pg 4C nucleus,corresponding to a 48.95% variation in genome size. In the 74collections studied, no correlation was observed between DNAcontent and habitat altitude. Variation in nuclear DNA contentwas analysed at the level of genus, subgenus, section and subsection.Variation in genome size was also studied within some species,either among widely separated populations or among differentintraspecific taxa. Very little variation in genome size wasdetected between populations, subspecies, and varieties of thesame species. The taxonomic implications of variation in nuclearDNA content are discussed.Copyright 2000 Annals of Botany Company Lonchocarpus (Leguminosae), DNA content, chromosome number.     

The biology and systematics of the genus Coincya Porta & Rigo ex Rouy (Cruciferae)

In this treatment, the genera Coincya (synonym: Hutera ) and Rhynchosinapis are regarded as one genus under the name Coincya which has nomenclatural priority. This study is based on data from morphology, population studies, cytology, ecology and reproductive biology reinforced by breeding experiments. Coincya is a west European genus comprising 14 taxa (including six species, five subspecies and three varieties).Eight new combinations are proposed and two species are excluded; R.nivalis is referable to the genus Brassica and R. Leplocarpa is probably referable to Erucastrum.
The chromosome number is either 2 n = 24 or 2 n = 48, which confirmed previous counts; C. Transtagana has not been counted. Breeding experiments were carried out with C. Longirostra, C.rupestris, C.monensis subsp. monensis , diploid and tetraploid races of subsp. recurvata var. recurvata , var. johnslonii , var. setigera , var. granatensis , subsp. hispida and subsp. puberula.
All taxa tested are outbreeding with a genetic self-incompatibility mechanism and are cross-compatible, suggesting that there has been no cytological differentiation between the diploid species in this study. The tetraploids formed semi-sterile triploids when crossed with diploids and although the chromosomes only formed bivalents and trivalents at meiosis it was postulated that the tetraploid was an autotetraploid of polytopic origin.
The evolution and differentiation of the genus and species are discussed.     

Low incidence of polyploids and high uniformity of karyotypes displayed by Delphinium (Ranunculaceae) in the Hengduan Mountains region of south‐west China

The chromosome numbers and morphology in 92 populations belonging to 49 species and three varieties in the genus Delphinium L. (Ranunculaceae), mostly from the Hengduan Mountains region of south‐west China, were studied. Forty seven species and three varieties were diploid, with 2n = 16, one species was tetraploid, with 2n = 32, and one species had diploid and tetraploid cytotypes. Three species had B chromosomes, representing the first time the occurrence of B chromosomes has been reported in the genus. The karyotypes of all the diploid species were quite uniform, commonly bimodal, and usually consisted of one pair of large median‐centromeric (m), one pair of large submedian‐centromeric (sm), five pairs of medium‐sized subterminal‐centromeric (st), and one pair of smaller sm (rarely st) chromosomes. The low incidence of polyploids in Delphinium from the Hengduan Mountains region indicates that polyploidy has played a minor role in the speciation of this highly diversified genus in the region. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 172–188.     

SYSTEMATIC INFERENCES FROM VARIATION IN ISOZYME PROFILES OF ARCTIC AND ALPINE CESPITOSE FESTUCA (POACEAE)

Variation in isozyme patterns was used to assess species boundaries in North American arctic and alpine representatives of the Festuca ovina L. complex. Isozyme profiles, in combination with chromosome number, delimit four discrete entities within the complex: F. brevissima Jurtzev (diploid); F. aggr. auriculata Drobov (diploid); F. brachyphylla Schultes (hexaploid); and tetraploid populations corresponding in morphology to F. baffinensis Polunin (arctic Canada) and F. minutiflora Rydberg (alpine United States). Although no fixed difference was detected between isozyme profiles of the latter two taxa, they are morphologically distinct. Thus variation in isozymes, morphology, and chromosome number delimits five taxa within the F. ovina complex in North America. Some alleles observed in the polyploid taxa were not detected among the diploids, and some observed in F. brachyphylla, the hexaploid taxon, were not detected in either the diploid or the tetraploid species. One possible explanation for these occurrences is that the North American polyploids originated in Eurasia, where many other potential diploid and tetraploid progenitors occur.     

云南乌头属牛扁亚属的核形态研究

对云南乌头属牛扁亚属３种、１变种共９个居群的核形态进行了研究。其中弯短距乌头、粗花乌头和滇川乌头的染色体数目和核型为首次报道。所有种类的静止核和前期染色体形态基本相似,分别属于复杂中央染色微粒型和中国型;分裂中期染色体数目为２ｎ＝４ｘ＝３２,染色体类型通常为ｓｍ或ｍ,ｓｔ染色体少见,染色体从大到小逐渐过渡,核型的二型性不明显。结合有关资料,重点指出了乌头属不但在亚属之间,而且在牛扁亚属内也存在着较     

A review of ploidy in the genus Prosopis (Leguminosae)

The genus Prosopis contains 44 species of trees and shrubs, the majority of which originate in the Americas. Most species are reported to be diploid, with a somatic chromosome number of 2 n  = 28. There are rare reports of polyploidy, although it is thought that these may represent polysomaty in root tissues. However, flow cytometry has recently indicated that P. juliflora is entirely tetraploid with a somatic chromosome number of 2 n  = 56. In order to clarify the situation, an extensive review of ploidy in Prosopis was undertaken, the first of its kind. The ploidy levels of 124 samples of Prosopis from 21 countries, including both the natural and introduced ranges, were analysed using flow cytometry. In addition, a comprehensive literature review was carried out, examining 305 published ploidy values and covering 32 of the 44 species of Prosopis . Flow cytometry analysis suggests that P. juliflora is the only tetraploid species, with a somatic chromosome number of 2 n  = 4 x  = 56, whilst the remainder of the species analysed are diploid with 2 n  = 2 x  = 28, including the first report for P. articulata (2 n  = 28). A critical review of published ploidy values shows that all species of Prosopis are reported to be entirely diploid, except P. glandulosa , P. juliflora , and P. koelziana , for which both diploid and tetraploid values have been recorded. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 425–438.