万寿竹六个居群的核型研究

本文研究了在云南境内的万寿竹Ｄｉｓｐｏｒｕｍ ｃａｎｔｏｎｉｅｎｓｅ Ｍｅｒｒ．从滇东南经滇中到滇西北不同居群间的核型变异。该种的染色体数目较为稳定,２ｎ＝１４,没有观察到不同数目的变异。六个居群的不对称性均属于３Ｂ型,但各个居群的核型结构表现出差异,核型间随体位置和数目的不同以及同源染色体的杂合性是居群间变异的主要特征,这种种内不同居群间核型的变异或许与该种的地理分布及生境有一定的相关性。     

明党参的遗传多样性研究

对珍稀特有单种属植物明党参的4个居群的材料,从物种生物学及保护生物学的角度,对它们 的遗传多样性进行了研究和分析。研究结果表明：各居群染色体数目恒定(2n=20),核型类型均为2A型,居群间存在核型多型性,主要表现为染色体的杂合性及随体染色体的位置也有一定变化。采用淀粉凝胶电泳方法,分析了10个酶系统,获得19个基因位点的资料,分析结果表明：居群的遗传变异处于较低水平,多态性位点比率P=33.35％,等位基因平均数A=1.43,等位酶基因多样度指数 H_o：0.03,H_e=0.07。总的基因位点变异中,有58％的变异来自于居群间,42％的变异存在于居群内,居群杂合体过量的位点仅为13％。偏东部居群的遗传多态性比西南部居群高。根据明党参居群遗传变异式样并结合相关研究,提出了其遗传多样性保护策略。     

八种国产葱属植物染色体研究

本文对国产葱属Allium 8个种的14个居群的染色体进行了研究。其染色体基数均为x=8,其中7个居群为二倍体(2n=2x=16),6个居群为四倍体(2n=4x=32),1个居群为多倍体复合体(2n=4x=32,2n=6x=48,2n=8x=64和2n=9x=72)。并发现随体染色体十分活跃,在多倍体中其数目并不都与其倍性相对应,并有“串状随体”现象出现;在有些类群中其形态变异较大,而随体染色体杂合形式的多态现象也较普遍。本文重点讨论了随体染色体的数目、形态变异及杂合现象在葱属进化中的作用,认为随体染色体形态变异及杂合现象的出现是葱属中遗传变异的重要源泉之一。并对葱属中的染色体基数及种内多倍性问题进行了初步讨论。     

青藏高原二种车前属植物的核型和C-值报道

对青藏高原平车前(Plantago depressa)18个居群和大车前(Plantago major)2个居群的染色体数目、核型和C-值进行了研究。结果表明:西藏亚东县和林芝县的平车前居群染色体数目为2n=4x=24;其它平车前和大车前居群的染色体数目均为2n=2x=12;染色体基数均为x=6;核型类型均为1A型,核型组成和前人的研究结果不尽相同。平车前的2C-值为首次报道,随着倍性水平的增加1Cx-值降低。大车前的2C-值和前人的研究结果存在着差异。平车前和大车前不同居群的2C-值发生了变异。流式细胞仪不能用来估测车前属植物的倍性水平。     

不同生态区云南黄连居群的染色体核型比较

采用根尖压片和卡宝品红染色法,对分布于高黎贡山的东、西坡不同生态带的8个云南黄连居群进行染色体核型比较分析。结果表明,8个居群染色体数目均为2n=2x=18,核型基本一致,除东坡一个居群为3A型外,其余均为2A型;总体上同一生态区域内各居群的核型表现出较大的相似性,但不同生态区域的居群间却存在较大的差异,主要为近端部和端部着丝点染色体的有无及数目在东西坡居群间存在较大变化;东坡居群的不对称程度均较西坡高。     

豹子花属及百合属13种25居群的核型研究

采用常规压片法对豹子花属6种11居群和百合属7种14居群进行了核型研究,并用不对称系数AI度量核型不对称性,以CVCL-CVCI散点图比较近缘类群之间的亲缘关系。结果表明： 1）除美丽豹子花 No-mocharis basilissa 为三倍体外,其余全为二倍体 2）核型在种间、居群间存在变异,特别是在随体染色体的数目和位置以及B染色体的有无上种间存在明显差别 3） CVCL-CVCI散点图显示豹子花属与百合属关系密切 4）染色体结构变异产生数量和类型不同的次缢痕,是豹子花属植物进化的主要方式。豹子花属在从其起源地和分化中心高黎贡山向四周扩散时,细胞核型方面伴随着出现了非整倍体、三倍体、 B染色体和次缢痕进化的类型.     

云南泸定百合8个野生居群的染色体核型分析

用常规压片法,对云南省境内泸定百合(Lilium sargentiae Wilson)8个野生居群的染色体进行了核型分析,结果显示:(1)野生泸定百合8个居群均为二倍体(2n=2x=24),染色体基数为12,共24条染色体,无B染色体;(2)核型类型均为3A,第1、2对染色体均为具中部(m)或近中部(sm)着丝点的大形染色体,且第1对染色体上均具有随体;(3)染色体长度比为1.64～2.26,平均臂比为6.43～8.22,核型不对称系数为79.82% ～ 81.77%。研究表明,泸定百合染色体数相对稳定,染色体变异主要表现在结构变异,各个居群的染色体组成、随体数、随体位置、臂比、染色体长度比及核型不对称系数均有差异,泸定百合各居群间存在明显的核型多态性。     

濒危植物三棱栎四个居群的核型

报道了濒危植物三棱栎 4个居群的染色体数目和核型 ,4个居群的核型公式均为 2n =14 =10m 2sm 2st 2bs,核型类型均为 2A。间期核为复杂染色中心型 (complexchromocentertype) ,细胞有丝分裂前期染色体为中间型 (interstitialtype)。 4个居群在前期染色体中 ,可观察到2个B染色体 ,但在中期染色体中较少发现。根据核型分析结果 ,4个居群间核型变异不明显     

黄牡丹八个居群的Giemsa C-带比较研究

应用ＢＳＧ方法对黄牡丹（Ｐａｅｏｎｉａ ｄｅｌａｖａｙｉ ｖａｒ．ｌｕｔｅａ）８个居群的Ｇｉｅｍｓａ Ｃ－带进行了比较研究。８个居群的所有染色体都在着丝点附近显示出了Ｃ－带,所有染色体的长臂上都没有显示Ｃ－带,而短臂上的Ｃ－带数量和位置在居群之间表现出了一定的差异。花甸凡居群手第二、第三、第四和第五对染色体显示端带;卓干山居群的第一、第三、第四和第五对染色体的短臂上没有显示Ｃ－带。在所研究的８个居     

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。     

A Cytological Study of Six Populations of Disporum cantoniense (Liliaceae)

Disporum cantoniense (Lour.) Merr. is widely distributed in the area from the Himalayas to Indonesia, via south China, Indo-China and Taiwan, especially in the various parts of Yunnan Province. In this paper, the karyotype variation of six populations of the apecies from southeastern, middle and northwestern part of Yunnan are studied. The result shows that the chromosome number of all the populations are 2n= 14. The species was reported to have 2n= 16, 30 (Hasegawa 1932, Mehra and Pathamia 1960, Kurosawa 1966, 1971, Tang et al. 1984) and 2n= 14 (Kurosawa 1971, Mehra and Sachdeva 1976a). 2n= 14, 2n= 16 and 2n=32 were observed in the material from Taiwan (Chuang, et al. 1962, Chao, 1963, Hsu, 1971, 1972, Chang, 1974). Based on the cytological study of D. megalanthum Wang et Tang and seven other species in this genus reported by other authors, Hong and Zhu (1990) consider that the basic number of this genus is x= 8, because species with 2n= 16 was more than those with 2n= 14, despite some number variation of chromosomes in this genus. Based on the results of the present paper, we consider that x= 7 might be one of the basic numbers of this genus. In the karyotypes studied here, the relative chromosome lengths and the ratio of the longest/the shortest chromosomes of the six populations are rather approximate. Moreover, all the karyotypes belong to Stebbins’3B type. However, karyotype variation was detected in these populations. The homologues of the 2nd, 3rd and 6th pair of chromosomes are different from each other, the numbers and popsition of satellites are found very different, among the populations except for the Lijiang population, the 1st, 2nd, 3rd or 4th pair of all the populations exhibited heterozygosity. Although all the karyotypes belong to Stebbins ‘3B type, the homologues were more regular in the Lijiang population than in the other populations, and the most irregular in the Wenshan population, because it hadfour pairs of heterozygous chromosomes.     

Chromosome number and ploidy-level in a Dutch population ofCrenobia alpina Dana (Planaria)

A Dutch population ofCrenobia alpina was found to have a chromosome number of 2n=42. One pair of large chromosomes is acrocentric and probably shows a secondary constriction; one small pair is acrocentric as well. All other chromosomes are metacentric or sub-metacentric; it has not been possible to discriminate with certainty between them. According to the hypothesis ofDahm (1958) populations with, 2n=42 are autohexaploid, the basic genome consisting of seven chromosomes. On basis of the karyotype it was concluded that the Dutch population described here, is not autohexaploid but functionally diploid, perhaps allohexaploid.     

矮牡丹小孢子母细胞减数分裂异常现象的观察

矮牡丹(Paeonia suffruticosa subsp. spontanea)(永济居群)存在多种结构杂合现象,减数分裂存在一些异常:如单价体、异形二价体、互锁四价体、六价体、后期I倒位桥、落后单价体、不均等分离、后期Ⅱ桥和微核等。统计了这些异常现象出现的频率,并对其形成的机制和对正常小孢子形成的影响进行了讨论。从细胞学水平上探讨了矮牡丹可能的濒危机制。同时结合前人的研究,对芍药属内3个组的结构杂合程度进行了比较。     

百合科扭柄花属一个新的染色体基数

对中国云南西部和西北部分布的腋花扭柄花Streptopus simplex的4个居群进行了细胞学研究。生长在云南西北香格里拉县(原中甸县)碧塔海和小中甸冷杉林中的腋花扭柄花两个居群的体细胞染色体数目为2n=2x=18,而生长在高黎贡山的福贡县片马和贡山县的灌丛中的植物体细胞染色体数目则为2n=2x=14。2n=14为腋花扭柄花一个新的染色体数目,x=7为扭柄花属一个新的染色体基数。香格里拉碧塔海和小中甸两个居群的核型公式分别为2n=4m+8sm+4st和2n=8m+2sm+6st,染色体逐渐变小;贡山和福贡片马两个居群的核型公式分别为2n=14=4m+10sm和2n=14=7m+7sm,其中第一对中部着丝粒的染色体显著大于其余染色体。由于x=8是扭柄花属最常见的染色体基数,因此可认为x=8是腋花扭柄花的染色体原始基数,x=7的数目是衍生的;x=7居群染色体的一条大染色体可能是由x=8的染色体的两条st型染色体的着丝粒发生了罗伯逊易位而来。     

Karyological studies of two populations of Juniperus communis L. in west Siberia

Results of a karyological study of Juniperus communis L. populations under swamp and dry conditions are presented. The chromosome number of J. communis are 2n = 22. Analysis of morphological chromosome parameters showed a similarity between karyotypes of both populations. It is possible to identify one pair of asymmetric chromosomes (VIII pair); this chromosome pair is close to submetacentric type. Three pairs of chromosomes (I, VII, VIII) have secondary constrictions. Other metacentric chromosomes form groups of five long (II--VI) and three short (IX-XI) pairs. Differences between two populations in absolute chromosomal length are observed.     

Cytogenetic analysis of three sea catfish species (Teleostei, Siluriformes, Ariidae) with the first report of Ag-NOR in this fish family

Despite their ecological and economical importance, fishes of the family Ariidae are still genetically and cytogenetically poorly studied. Among the 133 known species of ariids, only eight have been karyotyped. Cytogenetic analyses performed on Genidens barbus and Sciades herzbergii revealed that both species have 2n = 56 chromosomes and Cathorops aff. mapale has 2n = 52 chromosomes: Genidens barbus has 10 Metacentrics (M), 14 Submetacentrics (SM), 26 Subtelocentrics (ST), and 6 Acrocentrics (A), Sciades herzbergii has 14M, 20SM, 18ST and 4A, whereas Cathorops aff. mapale has 14M, 20SM, and 18ST. The nucleolus organizer regions (NORs) were found in a single chromosome pair on the short arm of a large-sized ST pair in Genidens barbus and on the short arm of a middle-size SM pair in Cathorops aff. mapale. Multiple NORs on the short arms of two large-sized ST pairs were found in Sciades herzbergii. The occurrence of diploid numbers ranging from 2n = 52 through 56 chromosomes and the presence of different karyotypic compositions, besides the number and position of NORs suggest that several numeric and structural chromosome rearrangements were fixed during the evolutionary history of this fish family.     

边陲黄耆和乌拉特黄耆的细胞学研究及其分类学订正

边陲黄耆和乌拉特黄耆间断分布于蒙新荒漠的西侧和东侧,二者在外部形态上接近,是一对易混淆的种。对这两个种的核型研究表明,边陲黄耆的核型公式为２ｎ＝１６＝１０ｍ（２ＳＡＴ）＋６ｓｔ,其中第１、２、３号染色体较长,其余染色体较短,核型呈现出明显的二型性,在第４号染色体（ｍ型）长臂上有明显的随体,而乌拉特黄耆的核型公式为２ｎ＝１６＝６ｍ＋６ｓｍ＋４ｓｔ（２ＳＡＴ）,其中除第１号染色体较长外,其余染色体相互     

杨山牡丹的核型分析

本文首次报道了杨山牡丹的核型及银染间期细胞核仁数目。结果表明,银染核仁数最多为6个;核型简式为2n=2x=10=6m(3 SAT)+2 sm (1 SAT)+2 s t (2 SAT), 其中第1和第4对染色体短臂上具1个随体,第2和第5对染色体短臂上具1对随体。此外,对国产芍药属二倍体种的随体数目及其杂合性等问题进行了初步讨论。 Abstract:In the paper,the karyotype and silver staining of nucleolar numbers of P.ostii Hong et Zhang were reported for the first time.The results show that nucleolar numbers are six at the most and karyotype formula is 2n=2x=10=6m(3 SAT)+2sm(1 SAT)+2st(2 SAT)of P.ostii.There are one satellite on each short arms of the first and fourth chromosomes and two satellites on each short arms of the second and fifth ones respectiuely.In addition,the satellitic numbers and satellitic heterozygosity of diploid species of Paeonia in China are briefly discussed.     

基于SSR标记探讨三种金花茶植物的遗传多样性和遗传结构

薄叶金花茶、小花金花茶和小瓣金花茶是三种濒危金花茶植物,为了解珍稀濒危植物遗传多样性和遗传结构,该研究利用微卫星标记对他们的7个种群共184个个体进行了遗传多样性和遗传结构分析。结果表明:11个位点共检测到等位基因92个。在物种水平上,小瓣金花茶平均等位基因数(N_A)为3.9、有效等位基因数(N_E)为2.328、观测杂合度(H_o)为0.520、期望杂合度(H_e)为0.501,高于薄叶金花茶和小花金花茶。在种群水平上,有效等位基因数(N_E)在1.788～2.466之间,期望杂合度(H_e)在0.379～0.543之间;种群间遗传分化系数(FST)在0.143 7～0.453 3之间,种群间基因流(N_m)在0.301 5～1.488 9之间。AMOVA分子变异分析显示65.72%的变异存在于种群内。三种金花茶具有较低水平的遗传多样性和高水平的种群间遗传分化。STRUCTURE和PCoA种群遗传结构分析结果将取样种群分为2组,即薄叶金花茶和小花金花茶大部分个体分为一组,小瓣金花茶大部分个体分为一组。现存所有种群应根据实际情况尽快采取就地保护或迁地保护措施。     

Karyotype study of 5 species of Costa Rican snakes of the colubrid family

The karyotypes of five species of colubrid snakes from Costa Rica are as follows: Imantodes cenchoa and Drymobius margaritiferus have a diploid number of 36, with 16 macro- and 20 microchromosomes. The fourth pair is heteromorphic in females of I. cenchoa, with a metacentric Z and a submetacentric W chromosomes. Karyotypes of Erythrolampius bizonus and Leimadophis epinephalus have 28 chromosomes, without a clearcut separation between macro- and microchromosomes. In the case of E. bizomus, the fourth pair contains the sex chromosomes Z and W, both are submetacentric, but the W is smaller. Xenedon rabdocephalus has a diploid number of 34 chromosomes (22 macro- and 12 microchromosomes); pair 3 is heteromorphic in females, with a submetacentric Z and a smaller metacentric W. The karyotype of X. rabdocephalus may be derived from a primitive karyotype by means of reduction in the number of microchromosomes and centric fissions of two pairs of metacentric autosomes.