绞股蓝属的染色体研究

报道了葫芦科绞股蓝属（Ｇｙｎｏｓｔｅｍｍａ Ｂ１．）８种共２０个居群的染色体数目,分别为２ｎ＝２２,３３,４４,６６,８８多倍体现象极为普遍。两个亚属;绞股蓝亚属（Ｓｕｂｇｅｎ．Ｇｙｎｏｓｔｅｍｍａ）和喙果藤亚属（Ｓｕｂｇｅｎ．Ｔｒｉｏｓｔｅｌｌｕｍ）的染色体基数均为Ｘ＝１１,并结合该属植物形态特征、繁殖方式和地理分布,对普遍出现的多倍体现象进行了讨论。     

国产十种乌头的染色体研究

本文描述了我国产毛茛科乌头属的10个种的染色体数目和形态。 根据该属染色体基 数为8(x＝8),可将这些种归为二倍体、四倍体、六倍体和八倍体种。 10种乌头的染色体在数目、大小、结构上表现出相关性。其中具根状茎而多年生的种多为二倍体,染色体形态较大,第3-7号多为近端着丝点(st)染色体, 具块茎而二年生的种多为多倍体,染色体形态较小,第3-7号多为近中着丝点(sm)染色体。染色体演化方向可能是二倍体→多倍体、大→ 小、st→sm。这进一步证明根状茎种较块茎种原始。根据染色体数目和形态,又可将这些种的染色体分为两类。这进一步支持了目前分类学上的牛扁亚属和乌头亚属的划分。本文还讨论了这些种的有关分类问题。     

10种菊属(Dendranthema)植物的细胞学研究

对菊属（Dendranthema）在中国分布的10种20个居群的材料进行了细胞学研究,首次报道了异色菊（2n＝18,36）、银背菊（2n＝56）、楔叶菊（2n＝18,72）的染色体数目和核型,以及蒙菊（2n＝18）的染色体数目新纪录,并结合前人的工作,分析了菊属的核型特征和演化趋势,及其与该属分类群的关系。     

山茶属植物的染色体数目和核型

本文对已报道的(包括作者的研究)山茶属植物的染色体数目和核型作一简单的讨论,结合地理分布情况,提出由二倍体向多倍体进化可能是山茶属植物进化的一个重要途径。山茶属植物的核型多为Stebbins核型分类的“2A”型,表明山茶属植物是一个较原始的种系。本文中12种的染色体数目和2种的核型为首次报道。     

10种菊属(Dendranthema)植物的细胞学研究

对菊属(Dendranthema)在中国分布的10种20个居群的材料进行了细胞学研究,首次报道了异色菊(2n＝18,36)、银背菊(2n＝56)、楔叶菊(2n＝18,72)的染色体数目和核型,以及蒙菊(2n＝18)的染色体数目新纪录,并结合前人的工作,分析了菊属的核型特征和演化趋势,及其与该属分类群的关系。     

栌菊木属及白菊木属的细胞学研究

对栌菊木属及白菊木属的染色体数目进行了首次报道,对栌菊木（Nouelia insignis Franch.)分布区内的10个居群进行了细胞学研究,染色体数目均为2n=54。白菊木属在中国分布的仅白菊木（Leucomeris decora Kurz)一种,对漾濞这个居群的细胞学研究表明,染色体也为2n=54。这两个属的基数可能x=9,它们可能为6倍体,结合帚木菊族已有染色体报道及形态特征,地理分布等初步分析表明：栌菊木种内分化程度小,是一自然类群;栌菊木和白菊木可能有着较近缘的联系;栌菊木可能是古老孑遗植物的后裔,为适应环境而多倍体化,得以保存下来。     

中国苹果属植物染色体数目报告

本文观察了中国苹果属植物17个种22个材料的染色体数目。观察结果指出,多倍体在全部研究材料中占44.6%,其中有些种因材料来源不同,其倍数性各异。本结果可供我国苹果遗传育种参考。     

10种菊属(Dendranthema)植物的细胞学研究

对菊属在中国分布的１０种２０ 个居群的材料进行了细胞学研究,首次报道了异色菊、银背菊、楔叶菊的染色体数目和核型,以及菊的染色体数目新纪录,并结合前人的工作分析了核特征和演经趋势,及其与该属分类的关系     

马蹄香属的核型及其系统学意义

本文对中国特有单种属－马蹄香属进行了细胞学研究,首次报道马蹄香花粉母细胞的单倍体染色体数目ｎ＝１３,体细胞的染色体数目为２ｎ＝２６,ｘ＝１３,核型公式为２ｎ＝１２ｍ＋４ｓｍ＋１０ｓｔ,染色体的范围２．５１－６．８０μｍ,为中型染色体,２Ｂ核型。这与前人报道的２ｎ＝２４,２Ａ核型和２ｎ＝４ｘ＝５２,染色体长度不超过１μｍ、是多倍体等结果均不相同。马蹄香是马兜铃科中最原始的属,核型资料表达它与细辛属部     

江西九江新公园猫爪草染色体数目错误报道的更正

对江西九江新公园猫爪草染色体数目的报道进行了改正,发现其染色体数目稳定,为2n=16,因此该种并不象前人所报道的那样是一个多倍体复合体。     

Ploidy variation in Buddleja L. (Buddlejaceae) in the Sino-Himalayan region and its biogeographical implications

The chromosome numbers of 27 populations of Buddleja , comprising 14 species, were counted. The basic chromosome number of all species was x  = 19, confirming previous reports. Different ploidy levels (2 n  = 38, 76, 114, 228) were observed in these taxa, representing diploids, tetraploids, hexaploids, and dodecaploids, respectively. The chromosome numbers of B. yunnanensis , B. brachystachya , and B. macrostachya are reported for the first time. The tetraploid 2 n  = 76 is a new ploidy level for B. myriantha . Particular attention was given to B. macrostachya , because of the variation in morphology and ploidy level between isolated populations of this species. Two types of interphase nuclei were recognized: the complex chromocentre type in B. macrostachya and the simple chromocentre type in the other species. Biogeographically, most of the polyploidy in the Asiatic species occurs in the Sino-Himalayan region. It seems to be associated with the uplift of the Himalayan Mountains, the orogeny of this region playing an important role in the evolution of polyploidy in these taxa.  © 2007 The Linnean Society of London. Botanical Journal of the Linnean Society , 2007, 154 , 305–312.     

Karyotype studies of some species of Dalechampia Plum. (Euphorbiaceae)

Karyotype studies in eight species of Dalechampia , including 10 natural populations, revealed chromosome numbers (2 n = 36, 46, 138 and 198) differing from two numbers cited in the literature (2 n = 44 and 72). The basic number x = 6, as in the genus Acalypha , may be considered ancestral in Dalechampia. Analysis of chromosome number, haploid chromosome length and karyotype symmetry suggests that the major chromosome mechanism acting in karyotype evolution of Dalechampia is polyploidy, but differences in chromosome morphology may be caused by chromosome rearrangements.     

Chromosome evolution in the genus Ophioglossum L.

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.     

国产姜科植物的染色体计数(2)

<正> 本文继续对国产姜科植物7属,14种和1栽培种作了染色体计数观察,其中9种和1栽培种是染色体计数的新纪录(表1,图1)。通过对大豆蔻Hornstedtia hainanensis的细胞学观察,初步确定大豆蔻属Hornstedtia的染色体基数为12(X=12)。     

青藏高原六种棘豆属植物的染色体数目及核型报道

对6种棘豆属植物（Oxytropis）的13个居群样进行细胞学研究,其中黄花棘豆（O．ochrocephala）、绢毛棘豆（O．tatarica）、甘肃棘豆（O．kansuensis）和铺地棘豆（0．humifusa）为首次报道染色体数目（2n=16）和核型;在胀果棘豆（O．stracheyana）中（2n=48）首次发现B染色体。现有的细胞学资料表明：棘豆属植物中多倍体占总报道数的58％,这说明多倍化在本属植物的进化过程中起着非常重要的作用,但青藏高原仅有一种植物发现多倍体,多倍化并不占主导地位,而主要表现为二倍体水平上的结构变异,即核型不对称性的变化。     

Cytotaxonomic analysis of South American species of Vernonia (Vernonieae: Asteraceae)

Chromosome numbers in 48 populations belonging to 31 species of Vernonia from South America have been determined. First chromosome counts are reported for V. propinqua var. canescens (2 n = 20), V. sceptrum (2 n = 80), V. rufogrisea (2 n = 32), V. heringeri (2 n = 32), V. hovaefolia (2 n = 64), V. hystricosa (2 n = 128), V. obtusata (2 n = 64), V. pseudoincana (2 n = 32), V. rubricaulis var.◊ australis (2 n = 64) and V. rugulosa (2 n = 30). The basic chromosome numbers x = 10, 14, 15, 16 and 17 were confirmed for New World species of Vernonia . Together with previous records, these numbers suggest that the evolution of Vernonieae has occurred through a combination of polyploidy and aneuploidy. Taxonomic implications of certain counts are also discussed.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 139 , 401–408.     

Chromosome number in South American species of Bothriochloa (Poaceae: Andropogoneae) and evolutionary history of the genus

Mitotic chromosome number of 14 taxa of Bothriochloa native to Argentina, Brazil and Uruguay were surveyed. Chromosome numbers of B. eurylemma, B. meridionalis and B. velutina are reported for the first time, with 2n = 6x = 60, and this ploidy level is the most common among the studied taxa. In addition, new cytotypes were found for B. alta (2n = 60), B. barbinodis (2n = 60), B. exaristata (2n = 80), B. laguroides var. torreyana (2n = 80), B. longipaniculata (2n = 60 and 80), B. perforata (2n = 60) and B. springfieldii (2n = 60). These numbers differ from those reported in the literature.     

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.     

Cytological and breeding behavior of pentaploids derived from 3x × 4x crosses in potato

Cytology and breeding behavior of Solanum commersonii - S. tuberosum hybrids derived from 3 x x 4 x crosses was examined. The chromosome number of hybrids ranged from hypo-pentaploid (2 n=5 x - 8=52), to hyper-pentaploid (2 n=5 x + 7=67), with the euploid pentaploid 2 n=5 x=60 class predominant. The high variability in chromosome number of the 3 x x 4 x hybrids was attributed to the fact that meiotic restitution during megasporogenesis of the 3 x female may have involved poles with various chromosome numbers, resulting in 2 n eggs with 24-48 chromosomes. Microsporogenesis analyses provided evidence that chromosome pairing between S. commersonii and S. tuberosum genomes occurred. In addition, chromosome distribution at anaphase I and anaphase II revealed an average chromosome number of 29.5 and 29.1 per pole, respectively. To further study the extent of transmission of extra genome chromosomes from pentaploids, 5 x x 4 x and 4 x x 5 x crosses were performed, and the chromosome number of resulting progeny was determined. Ploidy ranged from 2 n=4 x=48 to 2 n=5 x=60 following 5 x x 4 x crosses, and from 2 n=4 x + 1=49 to 2 n=5 x=60 following 4 x x 5 x crosses. These results provided indirect evidence that the pentaploid hybrids produced viable aneuploid gametes with a chromosome number ranging from 24 to 36. They also demonstrated that gametes with large numbers of extra chromosomes can be functional, resulting in sporophytes between the 4 x and 5 x ploidy level. Fertility parameters of crosses involving various (aneuploid) pentaploid genotypes were not influenced by chromosome number, suggesting a buffering effect of polyploidy on aneuploidy. The possibility of successfully using (aneuploid) pentaploid genotypes for further breeding efforts is discussed.     

大戟科野桐属4种6个居群的核型研究

采用常规压片法对大戟科野桐属4种(含变种)6个居群进行了体细胞染色体数目和核型研究。研究结果显示其染色体数目为2n=22或2n=44,核型均为1A。核型公式分别为:绒毛野桐2n=4x=44m;白背叶2n=20m 2sm或2n=2x=22m或2n=20m(2sat) 2sm;广西白背叶2n=2x=22m;毛桐2n=2x=22m。其中白背叶[Mallotus apelta(Lour.)Muell.-Arg.]、广西白背叶[M.apelta(Lour.)Muell.-Arg.var.kwangsiensisMetic.]和毛桐[M.barbatus(Wall.)Muell.-Arg.]的染色体数目和核型均为首次报道。根据野桐属细胞分类学资料推测,多倍化和异基数变异是野桐属属内物种形成的重要方式。