山茶属植物核型研究进展

本文收集整理了目前已发表的山茶属植物的核型资料。按张宏达的分类系统,本文共收录了94种（含15变种）的核型和29种（含4变种）的染色体数目。分析表明,山茶属植物染色体基数稳定X＝15,核型多为2A或2B型,核型的进化规律符合Stebbins提出的从对称向不对称方向进化的理论。山茶属植物的核型存在杂合性和多态性。本文中作者提供15种的核型,其中2种的核型为首次报道。     

云南大叶茶细胞学研究

本文采用去壁低渗法研究了云南大叶茶的染色体核型,间期核形态和多核现象。结果表明大多数染色体是中部着丝粒染色体,5对是近中部着丝粒染色体,第7和12对染色体中各有1条具随体染色体。根据Levan等的分类原则,其核型为2n=20m+8sm+2sm(SAT),属于Stebbins核型分类的“2A”型,同时亦发现有“2B”型的核型。云南大叶茶间期核型为浓密分散型和复杂染色中央微粒型两种;并首次发现茶树中的多核现象,在所观察的1250个细胞中有6个是具双核细胞(占0.48％),有2个是具三核细胞占(0.16％)。另外,本文还对部份山茶属植物的核型进行了讨论。从核型上可以看出:(1)山茶属植物在进化上属于较原始的种系;(2)山茶属植物核型的进化基本符合Stebbins提出的植物界核型进化的规律,即对称—→不对称;(3)山茶属植物的核型在一定范围内变异甚大,这种变异没有一定的规律性。这些观点与张宏达提出的山茶属植物的分类系统基本吻合。带随体的染色体数目在山茶属植物核型的进化上没有什么明显的变化规律。     

中国山茶属4种2变种核型研究

本文采用去壁低渗法研究了我国山茶属植物4种2变种的核型。根据Levan等的命名系统,各个种的核型可简式为大理茶2n=20m+2m(SAT)+8sm;勐腊茶2n=20m+2m(SAT)+6sm+2sm(SAT);德宏茶2n=20m+8sm+2sm(SAT);苦茶2n=20m+9sm+1sm(SAT);茶2n=18m+2m(SAT)+12sm;白毛茶2n=18m十2m(SAT)+9sm+1sm(SAT)。这些种都是二倍体种(2n=2x=30),未发现多倍体。在勐腊茶核型中发现2个超数染色体(B-chromosome)。核型的不对称性表明,这些种均属于Stebbins核型分类的2A型核型。这些种在“随体数目和位置,最长染色体与最短染色体之比,臂比大于2:1的染色体比例,着丝点端化值,染色体绝对长度”方面的变异是清楚易见的。核型的变异表明,这些种的染色体进化顺序为大理茶—→勐腊茶—→德宏茶—→普洱茶—→白毛茶—→苦茶—→茶。这一结果与张宏达提出的山茶属植物的分类系统基木吻合。本文还讨论了山茶属植物核型的杂合性和多态性。本文中勐腊茶、德宏茶、苦茶的染色体数目和核型及大理茶的核型为首次报道。     

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。     

三种紫金牛属植物的核型研究

对紫金牛属三种植物进行了核型分析,其中朱砂根染色体数目2n=46、核型2n=46=42m+2sm+2st和紫金牛核型2n=92=58m+24sm+10st为首次报道;虎舌红核型公式为2n=44=40m+2sm+2st。核型分析结果显示,紫金牛属植物存在染色体数目非整倍体变异及多倍化的进化方式。     

山茶属的细胞地理学研究

本文收集整理了山茶属的细胞学资料,以细胞地理学的方法探讨该属的起源和演化。在山茶属１４组１１９种植物中有１０组６２种已具染色体数目的报道,５４种已知核型,分别占总数的５２％和４５％。山茶属植物具有稳定的基数（ｘ＝１５）和多变的倍性（２ｘ→８ｘ）。每一个组都有二倍体或全为二倍体;多倍体主要出现在Ｓｅｃｔ．Ｃａｍｅｌｉａ、Ｓｅｃｔ．Ｐａｒａｃａｍｅｌｉａ和Ｓｅｃｔ．Ｔｈｅｏｐｓｉｓ之中,大多分布在山茶属分布区的西部、北部和西北部,呈现出北多南少的趋势。山茶属的核型遵守Ｓｔｅｂｂｉｎｓ的从对称向不对称演化的规律,分布中心靠南的组比靠北的组拥有更对称的核型,表明山茶属从南向北进化和扩散。在已具核型资料的组中,Ｓｅｃｔ．Ａｒｃｈｅｃａｍｅｌｉａ最原始,Ｓｅｃｔ．Ｃａｍｅｌｉａ最进化,包括Ｃ．ｙｕｎｎａｎｅｎｓｉｓ的Ｓｅｃｔ．Ｈｅｔｅｒｏｇｅｎｅａ不可能是山茶属最原始的类群。我们认为山茶属很可能起源于中南半岛,主要向北扩散和进化,在现今的分布中心发生了快速的分化,形成了大量种类     

蜘蛛抱蛋属的细胞分类学研究Ⅱ

文章报道了13种蜘蛛抱蛋属植物的染色体核型,并对属内核型进化规律作了总结。作者认为随体染色体和第1对染色体可以作为本属核型的特征染色体。染色体数目变异与花部式样密切相关。本属植物原始的染色体基数为x=19。此外,对非整倍性变异的主要机制也进行了讨论。     

12种酢浆草属植物核型分析

【目的】为了从细胞学角度明确12种酢浆草属（Oxalis）植物核型特征与亲缘关系,探究酢浆草属植物染色体的多样性,进一步为酢浆草种质资源鉴定与杂交育种亲本选择提供参考。【方法】应用根尖压片法对酢浆草属12个物种植物有丝分裂中期的染色体形态、数目及其核型进行观察分析。【结果】结果表明：（1）7个物种的染色体数目为首次报道,5种已报道物种中,兔耳酢浆草（O. fabaefolia）和黄花酢浆草（O. pes-caprae）染色体数目与前人报道一致,其余3种,与先前报道存在差异,其中2n=26为酢浆草属植物中首次报道的染色体数目,共发现7种染色体基数,其中x=13为首次报道,倍性范围从2x~6x;实际染色体大小范围为0.27~2.23 μm,着丝点位置为中部着丝点区（m）和亚中部着丝点区（sm）,核型类型共4种,核型不对称系数范围为56.31%~65.40%。（2）12种酢浆草属植物中兔耳酢浆草最为进化,扁平酢浆草（O. compressa）最为原始。（3）根据染色体核型相似性可将12个酢浆草属植物划分为4组。【结论】研究认为,12个酢浆草属物种具有广泛的核型多样性,核型分类结果与前人形态学分类不完全一致。     

九种水鳖科植物染色体数目及其核型分析

本文报道了我国产水鳖科植物5属9种染色体数目和核型,发现所有种都是二倍体,它 们的核型大部分是由中部着丝点(m)和近中部着丝点(sm)组成,少数种具有近端着丝点 (st)。它可以区分为4种核型：1A,2A和1B,2B。水筛属是原始的,黑藻属是进化的。     

蜘蛛抱蛋属植物的核型不对称性分析

报道了蜘蛛抱蛋属(Aspidistra)两种植物的染色体数目和核型,其中河口蜘蛛抱蛋(A.hekouensi)的染色体数目(2n=38)为首次报道,四川蜘蛛抱蛋(A.sichuanensis)染色体数目也为2n=38,但其核型与以往的报道有差别.使用染色体内不对称系数(A1)和染色体间不对称系数(A2)对该属34种植物核型的不对称性进行了分析,结果表明该属植物的核型似乎并没有向不对称性增强的方向演化.     

Chromosome Studies of 10 Species of Aconitum in China

This paper deals with chromosomal numbers and morphology of 10 species of Aconitum in China. According to the basic number of the genus (x=8), these species can be referred to diploid, tetraploid, hexaploid and octoploid. Correlation is found between chromosomal numbers, sizes and structures. The perennial species with a rhizome are mostly diploid, with chromosomes larger than those in the biennial species with a tuber, and their chromosome pairs 3-7 are mostly subterminal ones, whereas most biennial species are polyploid, and their chromosome pairs 3-7 are almost submetacentric. The evolutionary trends of chromosome from diploid to polyploid, large to small, st to sm are considered possible. The data are agreed with the idea that rhizomal species are more primitive than tuberous ones. The existence of two types of karyotypes in these 10 species is a further support of taxonomic division of two subgenera, subgen. Paraconitum and subgen. Aconitum. In addition, some species are taxonomically discussed.     

Chromosomes of sixteen European species ofLongitarsus flea-beetles (Coleoptera,Chrysomelidae)

Sixteen species ofLongitarsus have been chromosomally surveyed, showing a continuous range of even numbers from 2n=26 to 2n=32 chromosomes. Among the total of twenty-three known species, about 40% display a 14+Xy male karyotypic formula, the possible modal and most primitive one for the genus. The current taxonomy of species groupings is in good agreement with the chromosome numbers in some cases, but not in others. Also, there is no interrelationship between chromosome numbers and foodplant selection. The number of large bivalents at metaphase I is generally negatively correlated with the diploid value, suggesting the possible role of centric fusions coupled to shifts in the amount of chromatin as the main chromosomal changes in the evolution ofLongitarsus. The karyotypes of a few studied species are composed of metacentric chromosomes, some of them of rather large size, and a minute y-chromosome. A possible example of polymorphism for the chromosome number inL. nigrofasciatus is reported and briefly discussed.     

中国葱属单生组4种植物的核型研究

对葱属单生组Allium sect.Haplostemon Boiss.的4种8个地方居群的核型进行了研究,其中3个种的核型属首次报道。研究结果表明：除在棱叶韭内同时具二倍体、三倍体和四倍体居群外,所研究的其余种的居群均为二倍体。以本研究为基础,结合国内外对该组已有的细胞学研究,得出以下结论：（1）单生组的染色体基数为8,在组内存在1A和2A两种核型类型;（2）组内随体染体类型丰富,在该组物种的生存适应方面可能起重要作用;（3）有些种（如薤白A.macrostemohn,棱叶韭A.caeruleum等）表明出现明显的种内核型分化,有的种甚至在外部形态上也有分化;（4）高度不育的三倍体（棱杏韭）和和五倍体（薤白）居群靠小鳞茎和珠芽进行无性繁殖,以此保持群的稳定和扩大。另外,从生境、繁育制度、多倍化以及这三者之间的关系等方面分析,认为 在单生组中不同的生境有利于诱发染色体的结构作数目变异。多倍化和兼性无融合生殖繁殖制度并存,则有利于克服染色色体变异所带来的育性降低这一繁育障碍,同时使居群中所发生的染色体变异得以保存,因此,多倍化和普性无融合生殖繁育制度并存是该组中多倍体类群进化的重要机制之一。     

CHROMOSOMES AND CROSSING BEHAVIOR OF SOME SPECIES OF SANSEVIERIA

Menzel , Margaret Y. (Florida State U., Tallahassee), and James B. Pate . Chromosomes and crossing behavior of some species of Sansevieria. Amer. Jour. Bot. 47(3) : 230—238. Illus. 1960.–Approximately 20 species (28 clones) studied were diploids, tetraploids or hexaploids of the basic numbers x = 20; about 40% of the taxa were polyploid. All species had similar karyotypes, except for chromosome number. Five of 12 combinations of diploid species gave fertile F₁ hybrids; 4 studied cytologically showed 20 bivalents at metaphase I. Two triploid interspecific hybrids showed high trivalent frequencies. In contrast, multivalent formation in polyploid species was variable but rather low. Morphological relationships appeared reticulate among and between diploids and polyploids and did not coincide with barriers to crossing or to hybrid fertility. The following tentative hypothesis concerning relationships in the genus is proposed: Sansevieria is monophyletic and speciation has proceeded through genetic variation and hybridization at the diploid level and by allopolyploidy (of the segmental type) ; a low level of chromosome differentiation has accompanied speciation such that complete pairing occurs in diploid hybrids, but considerable preferential pairing occurs in allopolyploids. The occurrence of both polyploid and hybrid vigor, the fertility of hybrids between species differing greatly in morphology and physiology, and the high potential for vegetative propagation make the genus a favorable subject for breeding based on interspecific hybridization.     

中国木兰科11属40种植物的核形态研究

为了探讨木兰科属间系统学关系和一些种的分类学地位,对中国木兰科11属40种进行了核形态研究。所研究的20种木莲属植物都为二倍体,表明木莲属植物主要是在二倍体水平上进化的,不同的种类具有各自的遗传组成,细微的染色体结构变异可能导致种间形态发生了明显的变化。木兰属的染色体数目具多样性,表明属内存在着不同倍性水平上的进化,说明木兰属分布广泛、形态复杂多样有其细胞学基础。细胞学证据支持木莲属应为独立的属,不宜于归并到木兰属。已观察的含笑属都为二倍体,而木兰属玉兰亚属的大多数种类为多倍体。我们认为维持现有的含笑属的分类地位和范围是恰当的,不支持将含笑属和玉兰亚属合并为一属。拟单性木兰属都是多倍体。木兰科植物形态特征重叠,性状呈网状进化,细胞学证据在探讨一些大属属下种的分类地位时具有一定价值,但论及整个科的分类系统和属间亲缘关系时,作用比较微弱。本文在细胞学基础上,结合形态和地理分布,重点对木莲属一些种类的分类地位进行了讨论。     

Chromosome Numbers and Karyotypes of Six Oxytropis Species (Fabaceae) from the Qinghai Tibetan Plateau,China

Chromosome numbers and karyotypes of 13 populations of six Oxytropis species (Fabaceae) from the Qinghai Tibetan Plateau, China, were presented. The chromosome numbers and karyotypes in O.ochrocephala, O.tatarica, O.kansuensis and O.humifusa (2n=16) were reported for the first time. B chromosomes were found from O.stracheyana (2n=48). The basic chromosome number of x=8 is confirmed for the genus. The available chromosomal data indicate that polyploidy may have played an important role in the evolution of the genus, with the incidence of polyploidy in the genus reaching 58%. However, our results indicated that among the populations here examined only one was a hexaploid with 2n=48. Such a chromosomal pattern indicates that the karyotypic repatterning at the diploid level seems to be the predominant feature of chromosomal evolution in the Oxytropis species from the Qinghai Tibetan Plateau, and that sympatric speciation via hybridization and polyploidization has played a minor role in the species diversification of the genus from this area.     

Analysis of metaphase I chromosome association in species of the genus Aegilops

Summary Metaphase-I chromosome associations in every diploid and polyploid species of the genus Aegilops were studied using C-banding in order to analyse the cytogenetic behaviour of the whole complement as well as of specific genomes in different polyploid species. Differences were observed in the frequency of associations per cell among different species of the same ploidic level and even between species sharing the same genomic constitution. Differences were also found between different genomes within the same polyploid species and between the same genome when present in several diploid and polyploid species. Several factors proposed as having an influence on the frequency of metaphase-I associations, such as chromosome morphology, C-heterochromatin content, genetic control and genome interactions, are discussed. Most of the polyploid Aegilops species showed a diploid-like behaviour at metaphase I although multivalents involving homoeologous associations were occasionally observed in Ae. biuncialis, Ae. juvenalis and Ae. crassa(6x); therefore, the Aegilops diploidising genetic system is not equally effective in all polyploid species.