葱属Amerallium亚属（石蒜科）的系统发生与性状进化

运用贝叶斯和简约法对葱属（Allium）Amerallium亚属的核糖体DNA内转录间隔区（ITS）进行了分析,对该亚属的系统发生进行了推测。系统分析证实 Amerallium是单系的,并表明该亚属由三个隔离的地理群组成：北美Ameralliums,地中海区Ameralliums和东亚Ameralliums。性状进化的重建表明鳞茎是原始或祖先状态,根状茎和肉质增粗的根是衍生状态且在Amerallium这个亚属的类群中独立进化发生了几次。重建也表明该亚属的原始染色体基数x=7,其它染色体基数（x=8, 9, 10, 11）是由它转化而来的。在北美类群中,异基数性相当罕见,而多倍性似乎是一个相对频繁的进化事件。在地中海区类群和东亚类群中,异基数性和多倍性是染色体进化的两个主要驱动力。     

八种国产大戟属植物的核型报道

8种大戟属Euphorbia L．植物的核型分析结果表明,大戟属不同亚属的染色体基数与其形态变 异的复杂性有一定关系。地锦草亚属subgen．Chamaesyce 3个种染色体基数分别为x=8,9,11;一品红 亚属subgen．Poinsettia两个种染色体基数均为x=7,分别为四倍体和八倍体;乳浆大戟亚属subgen． Esula 3个种,染色体基数分别为x=7,10,10。根据以前学者发表的资料分析,一品红亚属和大戟亚属 Subgen. Euphorbia的染色体基数是很稳定的,分别为x=7和x=10;通奶草E．hypericifolia为x=8 的四倍体,它不仅有染色体整倍性的变异,还有异基数性的变化。结合以前学者的研究,笔者支持x= 10为大戟属的最原始基数的观点。齿裂大戟E．dentata和通奶草具不同的染色体倍性,猫眼草E． esula的细胞染色体数目观察证实了我国存在四倍体的居群,与欧洲和北美的植物构成一个典型的多倍体复合体。     

禾本科虎尾草亚科细胞学研究分析

总结了虎尾草亚科72属601个分类单位的细胞学资料。虎尾草亚科的染色体基数是10和9,来源于原始染色体基数6经非整倍性减少为5,再经多倍化及非整倍性减少而来。细胞学性状对虎尾草亚科属上类群的分类具有相当重要的价值。推测染色体基数演化的趋势为:x=6→x=5→x=10→x=9。据认为,虎尾草亚科的原始染色体基数为5的二倍体类群在演化早期就灭绝了。     

天门冬科黄精族细胞学研究进展

在全面收集和整理黄精族染色体数据的基础上,对国内外有关黄精族各类群间的染色体数目和倍性的变化规律进行了总结,并从染色体的多倍化和非整倍化与系统发育关系和地理分布方面探讨了黄精族内各属的起源和演化关系问题。黄精族包括黄精属、舞鹤草属、异黄精属和竹根七属,共约100余种,其中舞鹤草属(x=18)、异黄精属(x=16)和竹根七属(x=20)的染色体基数稳定,而黄精属染色体基数波动较大,主要为x=8~16,既有多倍化也有非整倍化现象。染色体数据表明黄精族4个属的染色体进化模式各不相同,揭示了黄精族内染色体从高基数向低基数演化的规律;各属内染色体的演化主要是体现在二倍体水平上的核型变异,多倍化在本族中不占主导地位;仅黄精属内伴有非常强烈的非整倍化现象;细胞学证据与分子系统发育的结果比较吻合,为黄精族内属间以及属下的系统发育与进化提供了重要的参考资料。     

菝葜属和肖菝葜属的核型变异和系统演化研究

基于体细胞染色体核型及花序特征对菝葜科Smilacaceae菝葜属Smilax和肖菝葜属Heterosmilax进行了系统演化研究,报道了国产菝葜科17个分类群的核型。根据已研究的部分形态学特征和已有的核型和分子序列资料,对它们的系统进化进行了分析。结果显示：（1）整个类群的核型变异表现在二型化、多倍化、染色体的微变异以及染色体基数递减（从16-15-13）,16为菝葜类群的基本染色体基数。（2）草本菝葜的核型对称性在东亚到北美种类中,表现出从对称到不对称的变化,而木本菝葜的各组间并未表现出这种趋势。（3）先出叶（prophy11）是宿存的芽鳞,因此在菝葜组sect．China和土茯苓组sect．Coilanthus中具花序的分枝（该分枝基部具先出叶）与圆锥菝葜组sect．Macranthae和穗菝葜组sect．Smilax中着生叶腋的花序分枝或者具关节的单伞形花序是同源的;结合ITS资料,推测花序原始类型是具伞形花序无总花梗呈穗状排列的种类。从祖先类型,花序的分化朝两个方向：一为菝葜属的菝葜组和土茯苓组以及肖菝葜属的全部种类为代表的生于叶腋的单伞形花序,另一为菝葜属的圆锥菝葜组sect．Macranthae的全部种类构成的圆锥．伞形花序。（4）肖菝葜属的核型和ITS数据都表明其为非单系类群,与草本菝葜和土茯苓组成员为姐妹群,首次发现花被2／3联合的过渡类型——筐条菝葜S.corbularia,建议将肖菝葜属降为亚属,置于菝葜属。（5）核型特点支持草本菝葜是东亚起源,扩展到北美,与土茯苓组种类有共同祖先．来自于x=16的木本菝葜,赞同恢复草本组sect．Nemexia。（6）在广布种菝葜S.china中首次发现二倍体居群,已知其存在3种倍性（2x、4x和6x）,发现不同倍性居群的分布规律,推测在第三纪至更新世中期日本、台湾岛与大陆分离之前,菝葜的叙居群已广泛分布,而目前广泛分布的缸居群是岛屿与大陆分离后形靠的。（7）我国西南是菝葜科现代分布和分化中心。     

半夏属的染色体数目、倍性与珠芽发生的关系

本文通过对半夏属Pinellia 5个种10个群体的染色体计数和珠芽数量统计,首次报道了5个染色体数目,同时发现珠芽的发生与染色体基数及多倍化程度有关：x=13的类群无珠芽,而x=9的有珠芽;在有珠芽的半夏P．ternata(Thunb．)Breit．中,平均每叶珠芽数随倍性的提高而增大。半夏是一个多倍体复合种,起源于无珠芽、染色体基数为x=7～9的二倍体祖先,可能是在该属的早期进化中由鹞落坪半夏P.yaoluopingensis X．H．Guo et X．L.Liu的x=13经非整倍性跌落而成,在发生上比鹞落坪半夏进化。     

13种21居群葱属植物的细胞分类学研究

采用常规压片法,对13种（含1变种）21居群葱属（Allium L.）植物进行了细胞分类学研究。结果表明：所研究类群的染色体基数为7、8和11,核型的类型为2A、2B和3A型,并且存在2倍体、3倍体和4倍体。主要讨论了葱属根茎组（Sect.Rhizirdium G.Don）部分类群的核型分化和进化机制,高山韭（A.sikkimense Baker）和多星韭（A.wallichii Kunth）的细胞地理学,以及B染色体的多态性及其在生境上的适应意义。最后在本研究的基础上,结合前人的细胞分类学研究结果,对葱属植物的核型进化形成了如下认识：（1）该属植物的原始染色体基数为8,其他基数的类群是由基数为8的类群进化而来的;（2）葱属植物在核型类型的进化上存在两条路线：基数为7的类群核型进化趋势为2A→2B→2C,而基数为8的类群的核型进化趋势为1A→2A→2B→2C;（3）多倍化是葱属植物进化的重要机制之一。     

桔梗科的地理分布:关于分布中心问题

对桔梗科44个属的分布作了分析,发现属的3个频度分布中心：东亚区(13个属),开普区(10个),地中海区(14个)。东亚区有12个属集中分布于中国西南部(云南东部和北部、四川西南部和贵州西南部);在地中海区属的分布相对均匀,但巴尔干半岛比较集中,有9个属。因此中国西南部是桔梗科属的最集中分布的中心。对桔梗科作了尝试性的划分,将该科分为6个类群,7个亚类群。东亚是类群和亚类群最集中分布的地区,因此可以称为类型的多样性中心。本文选择Polemoniaceae为外类群,把Cyphiaceae和Lobeliaceae作为参考类群,并考虑一般承认的进化原则,据此分析了26个性状的演化趋势,进而计算出每一个属的性状原始指数,并据此确定各属的原始性和进化性。最原始的属和大部分比较原始的属分布在东亚,因而可以认为东亚,特别是中国西南部,是桔梗科的原始类型中心。这个地区也就是康滇古陆的所在地,地史上一直稳定,为桔梗科原始类群的分化提供了历史地理背景,这里就是原始类群分化、发展的地区,推测桔梗科起源于白垩纪,但具体的起源地难于判断。     

基于染色体计数和ITS序列初步探讨横断山区柴胡属植物(伞形科)的系统发育

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。     

水晶兰属植物的染色体

对国产水晶兰属植物水晶兰（Monotropa uniflroa L．）和毛花松下兰（M．hypopitys var．hirsutea Roth）的花粉母细胞减数分裂进行了观察,它们的减数分裂中期Ⅰ的染色体数目均为n=24。结合前人所做的研究,确定该属的染色体基数为x=8,并对该属的染色体基数和倍性变异与地理分布区的关系进行了初步探讨。通过对鹿蹄草亚科和水晶兰亚科的染色体基数比较,结合两个亚科的生长习性和花药开裂方式的不同,作者赞同哈钦松系统将水晶兰亚科作为科的处理。     

Karyotypes of eight species of Euphorbia L. (Euphorbiaceae) from China

In this paper, eight species of the genus Euphorbia L. were cytologically studied. The three species of the subgenus Chamaesyce Raf., E. hirta, E. humifusa and E. hypericifolia, had chromosome numbers of 2n = 18, 22 and 32, with their basic chromosome numbers being x = 9, 11 and 8 respectively. The two species of the subgenus Poinsettia (Grah.) House. E. dentata, with 2n=28, a tetraploid, and E. cyathophora, with 2n= 56, a octoploid, had both the basic chromosome number of x= 7. The three species of the subgenus Esula Pers, E. lathyris, E. helioscopia and E. hylonoma, had chromosome number of 2n= 20, 42 and 20, with their basic numbers being x= 10, 7 and 10 respectively. The basic chromosome number of x = 8 is new for E. hypericifolia, in which x = 7 was previously reported. This indicates that this species had both ploidy(2n = 4x = 28, 8x = 56) and dysploidy(x = 7, 8) variations. In E. dentata, there occurred also ploidy variation (2n = 2x, 4x and 8x). A tetraploid cytotype of E. esula was found in China, its diploid cytotype and hexaploid cytotype being previously reported in North America, the Iberian Peninsula and some other European areas. Based on our results and those previously reported, we support the viewpoint that x＝10 may be the original basic chromosome number of Euphorbiaand discuss the role of polyploidy and dysploidy in the speciation and evolution of this genus     

Karyotypic Changes through Dysploidy Persist Longer over Evolutionary Time than Polyploid Changes

Chromosome evolution has been demonstrated to have profound effects on diversification rates and speciation in angiosperms. While polyploidy has predated some major radiations in plants, it has also been related to decreased diversification rates. There has been comparatively little attention to the evolutionary role of gains and losses of single chromosomes, which may or not entail changes in the DNA content (then called aneuploidy or dysploidy, respectively). In this study we investigate the role of chromosome number transitions and of possible associated genome size changes in angiosperm evolution. We model the tempo and mode of chromosome number evolution and its possible correlation with patterns of cladogenesis in 15 angiosperm clades. Inferred polyploid transitions are distributed more frequently towards recent times than single chromosome gains and losses. This is likely because the latter events do not entail changes in DNA content and are probably due to fission or fusion events (dysploidy), as revealed by an analysis of the relationship between genome size and chromosome number. Our results support the general pattern that recently originated polyploids fail to persist, and suggest that dysploidy may have comparatively longer-term persistence than polyploidy. Changes in chromosome number associated with dysploidy were typically observed across the phylogenies based on a chi-square analysis, consistent with these changes being neutral with respect to diversification.     

New Chromosome Counts of Some Dicots in the Sino-Japanese Region and Their Systematics and Evolutionary Significance

New somatic chromosome numbers for nine species eight families and eight gen era in the Sino-Japanese Region are reported here as shown in Table 1. Data of six genera are previously unknown cytologically. The bearings of these new data on the systematics and evolution of the related species, genera or families are discussed as follows: (1) Platycarya strobilacea Sieb. et Zucc. (Juglandaceae). The chromosome number of this species is 2n=24, with a basic number of x=12, which deviates from 2n=32 occurred in Juglans, Carya, Pterocarya and Engelhardtia with the basic number x= 16. The Juglandaceae appears to be fundamentally paleotetraploid, with an original basic number of x = 6 in Platycarya and x-8 in the other four genera, although secondary polyploidy occurs in Carya. Based on the remarkable morphological differences between Platycarya and the rest seven genera of the family, Manning (1978) established two subfamilies: Platycaryoideae for Platycarya and Juglandoideae for the other genera. Iljinskaya (1990), however, recently established a new subfamily: Engelhardioideae for Engelhardtia. Lu (1982) points out that because of a great number of primitive characters occurring in Platycarya, the genus could not be derived from any other extant juglandaceous taxa but probably originated with the other groups from a common extinct ancestor. The present cytological data gives support to Manning′s treatment. We are also in favor of Lu′s supposition and suggest that basic aneuploid changes, both ascending and descending, from a common ancestor with the original basic number x=7, took place during the course of early evolution of the Juglandaceae and led to the origin of taxa with x=6 and 8. Subsequent polyploidy based on these diploids occurred and brought forth polyploids of relic nature today, whereas their diploid progenitors apparently have become extinct. (2) Nanocnide pilosa Migo (Urticaceae). The chromosome number of this Chinese endemic is 2n-24, with a basic number of x=12. An aneuploid series occurs in the Urticaceae, with x--13, 12, I1, 10, 9, 8, 7, etc. According to Ehrendorfer (1976), x = 14, itself being of tetraploid origin, is the original basic number of the whole Urticales, and descending aneuploid changes took place in the early stage of evolution of the Urticaceae and Cannabinaceae. In addition to Nanocnide, x= 12 also occurs in Australina, Hesperonide and Lecanthus, and partly in Chamabainia, Elatostema, Girardinia, Pouzolzia and Urtica. (3--4) Sedum sarmentosum Bunge and S. angustifolium Z. B. Hu et X. L. Huang (Crassulaceae). The former is a member of the Sino-Japanese Region, while the latter is only confined to eastern China. The chromosome number of Sedum is remarkably complex with n=4-12, 14-16…74, etc. S. angustifolium with 2n=72 of the present report is evidently a polyploid with a basic number of x =18 (9^?) Previous and present counts of S. sarmentosum show infraspecific aneupolyploidy: n = c. 36 (Uhl at al. 1972) and 2n=58 (the present report). These two species are sympatric in eastern China and are morphologically very similar, yet distinguishable from each other (Hsu et al. 1983) S. sarmentosum escaped from cultivation in the United States gardens exhibited high irregularity in meiosis (Uhl et al. 1972). Uhl (pets. comm. ) suspected strongly that it is a highly sterile hybrid. R. T. Clausen (pets. comm.) found that plants of S. sarmentosum naturalized in the American Gardens propagated by means of their long stolons and broken stem tips, and could not yield viable seeds. Hsu et al. (1983) found that some of the plants of S. sarmentosum and S. angustifolium did yield a few seeds, but other did not. These species are, therefore, by the large vegetatively apomictic. (5) Glochidion puberum (L. ) Hutch. (Euphorbiaceae). The genus Glochidion includes about 300 species, but only eigth species from the Himalayas have been studied cytologically, with n= 36 and 2n= 52, having a basic number of x= 13. The present count for the Chinese endemic G. puberum establishes the tetraploid chromosome number 2n= 64, and adds a new basic number x= 16 to the genus. (6) Orixa japonica Thunb. (Rutaceae). Orixa is a disjunct Sino-Japanese monotypic genus. Out of the 158 genera of the Rutaceae, chromosome numbers of 65 genera have hitherto been investigated, of which 42 genera are with x=9 (66.61%), some with x=7, 8 and 10, and rarely with x=13, 15, 17 and 19. The present count of 2n=34 for O. japonica may have resulted from a dibasic tetraploidy of n=8+9. (7) Rhamnella franguloides (Maxim.) Weberb. (Rhamnaceae). The chromosome number of this member of the Sino-Japanese Region is 2n= 24. with a basic number of x= 12. The basic number x= 12 also occurs in Hovenia, Paliurus, Sageretia, Ceanothus and Berchemia. Hong (1990) suggested that x= 12 in Rhamnaceae may be derived from descending aneuploidy of a paleotetraploid ancestor. (8) Sinojackia xylocarpa Hu (Styracaceae). The chromosome number of this rare Chinese endemic is 2n= 24, with a basic number of x =12, which is identical with that in Halesia and Pterostyrax, but deviates from that in Styrax (x=8). The basic number x=8 in the Styracaceae may be derived from the original basic number x=7 by ascending aneuploidy in the early stage of evolution of the family, and x=12 may be derived from polyploidy. (9) Thyrocarpus glochidiatus Maxim. (Boraginaceae). The chromosome number of this Chinese endemic species is 2n=24, with a basic number of x=12. An extensive aneuploid sequence of x = 4-12 occurs in the Boraginaceae, of which x = 8, 7 and 6 are the most common. The basic number x=12 also occurs in Cynoglossum and Mertensia. It is evident that aneuploid changes, both descending and ascending, from an ancestor with x = 7, have taken place in the primary phase of evolutionary diversification of the Boraginaceae, and subsequent polyploidy has given rise to x=15, 17 and 19 in a few genera (e. g. Amsinskia and Heliotropium). The origin of x=12 is not certain. Either it be a result of ascending aneuploidy, or a product of polyploidy on the basis of x = 6. The present authors are in favorof the latter.     

First chromosome number determinations in south-eastern South American species of Lupinus L. (Leguminosae)

Chromosome numbers are presented for the first time for 30 accessions of nine south-eastern South American Lupinus species. Chromosome numbers of 2 n = 32 and 34 were found for L. bracteolaris (three out of five accessions with 2 n = 32) and L. linearis (two out of three accessions with 2 n = 32), and of 2 n = 36 for L. gibertianus , L. lanatus, L. magnistipulatus , L. multiflorus , L. rubriflorus , L. reitzii and L. uleanus . All the South American species examined have relatively low chromosome numbers when compared with most of the Old World and North American species. Our results, where 2 n = 36 is the rule, are in sharp contrast to the data for North American Lupinus species and reveal the following: (1) low chromosome numbers are the rule, at least in the southern part of eastern South America; (2) cytologically, the eastern South American species form a group distinct from the North American taxa; (3) high levels of polyploidy have not played as important a role in evolution and speciation in eastern South America as in North America; (4) the predominance of low chromosome numbers in eastern South American species and the existence of similar numbers in two of the six rough-seeded Old World species support the hypothesis that in the evolution of the genus the eastern South American species branched off first, followed by the rough-seeded group.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Socety , 2002, 139 , 395–400.     

Phylogenetic inference of the genus Bupleurum (Apiaceae) in Hengduan Mountains based on chromosome counts and nuclear ribosomal DNA ITS sequences

pleurum of Apiaceae in China. This paper reports chromosome numbers of six species and two varieties of Bupleurum, and for four species and two varieties their chromosome numbers are reported for the first time. The phylogeny of Bupleurum was investigated based on the ITS region of the nuclear ribosomal DNA (nrDNA) of 14 taxa from the Hengduan Mountains, 3 taxa from the North China (Hebei and Heilongjiang), and 16 taxa from Africa and the Mediterranean region. Varia-tions in chromosome numbers and the ITS sequences were used to infer phylogenetic relationships between Bupleurum species in Hengduan Mountains. The results showed that the Hengduan Mountains might represent one of the frequency and diversity centers for Bupleurum. The ancestors of Bupleurum species in the Hengduan Mountains may be related to the woody B. fruticosum in North Africa, or the species in the western Mediterranean region. It is postulated that the ancestral population migrated into Hengduan Mountains through the Middle East and the Caucasus. Furthermore, the neo-endemic B. mundtii in South Africa appeared to be a close relative of the species in the Hengduan Mountains. In the trend of basic chromosome number evolution, x = 8 should be regarded as the ancestral basic number, while x = 6, 7 as the derived ones. The Bupleurum species in the Hengduan Moun-tains have been undergoing changes in the basic chromosome numbers or the ploidy level. The ITS phylogenetic tree showed that the Chinese species were divided into two clades: one with the basic chromosome number x = 8, and the other with x = 6, 7. The results rejected the previous infrageneric classification of Bupleurum in China. We further suggested to raise B. marginatum var. stenophyllum to species rank based on the combined evidence from morphology, karyology, pollen morphology, and the ITS phylogenetic tree.     

Contribution to the karyological knowledge of Echinops (Asteraceae, Cardueae) and related genera

Twenty-six chromosome counts were made of several genera of the tribe Cardueae from various European and Asian provenances: Acantholepis (one species studied), Amphoricarpus (1), Chardinia (1), Echinops (14 species, 15 populations), Siebera (1), Staehelina (3) and Xeranthemum (4). Eleven of the reports are made for the first time, ten confirm previous counts, while the remainder report disparities with earlier records. The existence of different basic chromosome numbers and ploidy levels suggests dysploidy and polyploidy as the main mechanisms of chromosomal evolution in the taxa considered.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 337−344.     

中国西南地区鹿药属4种15居群核型研究

对产于中国西南部的鹿药属（Maianthemum）4种植物进行了细胞学研究,包括染色体数目,多倍化,非整倍性和随体染色体,以及核型不对称性和核型进化。结果表明：1）除了在云南丽江采集的Maianthemum tatsienensis染色体数目为2n=72之外,其余的居群全为2n=36;2）核型在居群间存在变异,特别是在具中部染色体和近中部染色体的数目以及随体染色体的数目和位置上。此外,M．nanchuanense和M．szechuanicum的核型是首次报道,B染色体也是首次在该属中发现。我们推测鹿药属的进化方式包括频繁的染色体畸变以及不同水平上的多倍化,而中国西南部是该属的分化中心。