向日葵染色体Giemsa C-带带型分析

采用HKG(HCl-KOH-Giemsa)法对内葵杂3号三交种染色体进行了C-分带研究和分析。结果表明:每条染色体至少都有一条C-分带,染色体组共有62条C-分带,以中间带和着丝点带为主,中间带主要分布在染色体短臂上;C-分带强弱差异明显,其中46条强带,16条弱带。Giemsa C-分带带型公式为:2n=2x=34=8I++3T++5I+I+T++4C+2CI+4CI++3CI++I+T++CT++2CT+。每条染色体都显示出显著的带纹特征,因此,利用Giemsa C-分带方法可以将向日葵的每条染色体区分开。     

向日葵染色体Giemsa C-分带研究

采用HKG (HCI-KOH-Giemsa)法对内葵杂3号三交种染色体进行了C-分带研究和分析.结果表明:每条染色体至少都有一条C-分带,染色体组共有62务C-分带,以中间带和着丝点带为主,中间带主要分布在染色体短臂上;C-分带强弱差异明显,其中46条强带,16条弱带.Giemsa C-分带带型公式为:2n =2x =34 =8I++3T++5I+I+T++4C +2CI+4CI+ +3CI+ +I+T++CT++2CT+.每条染色体都显示出显著的带纹特征,因此,利用Giemsa C-分带方法可以将向日葵的每条染色体区分开.     

宜昌百合根尖染色体C-带分析

利用Giemsa C-带方法对宜昌百合（Lilium leucanthum(Baker) Baker）进行研究。结果表明：宜昌百合（L. leucanthum）的染色体数目为2n＝2x=24,单套染色体的条带总数目为21条。其带型公式为：2n＝24＝6C+2CI+2I+2CI⁺+2CI⁺+4I⁺+2I⁺+2T⁺+2I+S。宜昌百合（L. leucanthum）每条染色体上都显示出显著的特征带,且带纹的深浅差异明显。宜昌百合（L. leucanthum）的强带主要集中在着丝点及附近区域。通过Giemsa C-带方法可以将宜昌百合（L. leucanthum）的每条染色体区分开。     

芥蓝和结球甘蓝染色体组型及C-带带型的研究

本文用改进的染色体标本制片技术,研究了芥蓝和结球甘蓝的染色体组型和 C-带带型。两种植物的二倍体均由4对中着丝粒、5对亚中着丝粒染色体组成,其中一对为随体染色体。芥蓝和结球甘蓝具有统一的染色体组型公式:2n=18=8m+10sm(2SAT),但两者的某些染色体在编号顺序上有差异。在结球甘蓝中观察,到4种不同形态的随体。用 BSG C-带方法得到 C-带带型,带型公式,芥蓝为2n=18=CITS 型=10C+2CI_++4CT~++2CS;结球甘蓝为2n=18=CITS 型=8c+2CI_++6CT~++2CS。某些带纹具多态性和杂合性。本文从染色体水平上讨论了芥蓝与甘蓝的亲缘关系。     

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。     

二种薏苡的核型和C-带带型的研究

川谷和薏苡的核型极为相似,2n=20=18m(2SAT)+2sm,属较为对称的核型。它们的C-带带型也极为相似,多数为端带,少数为弱近端带,没有着丝点带,薏苡的带比川谷的带要丰富些。川谷的C_-带带型可表示为:2n=20=6T_++2T_+~++2T_+S+10,薏苡的C_-带带型为:2n=20=6T_++6T~++6T_+~++2S。     

黄精属的细胞分类学研究——Ⅱ.8个种的核型和进化

作者研究了中国产黄精属8个种的核型,结果如下:热河黄精,2n=22=14m(4SAT)+2sm(SAT)+6st;多花黄精,2n=22=8m+8sm(2sc)+6st(2sc);玉竹,2n=20=12m+8sm;小玉竹,2n=20=8m(2sc)+8sm+4st;长梗黄精,2n=16(18)=10m+4sm+2st;二苞黄精,2n=18=8m+10sm;黄精,2n=24=4m+8sm(2sc)+12st(2sc);卷叶黄精,2n=20=12m(2sc)+8sm。作者推测该属的染色体基数x=10。染色体数目进化的趋势是:非整倍性变异为主,整倍性变异为次;上升性变异为主,下降性变异为次。按照核型不对称程度,8个种的核型可分为三个等级。核型由对称向不对称进化是与染色体数目的进化趋势大体上相关的。     

黄精属的细胞分类学研究Ⅰ.8个种的核型和进化

作者研究了中国产黄精属8个种的核型,结果如下:热河黄精,2n=22=14m(4SAT)+2sm(SAT)+6st;多花黄精,2n=22=8m+8sm(2sc)+6st(2sc);玉竹,2n=20=12m+8sm;小玉竹,2n=20=8m(2sc)+8sm+4st;长梗黄精,2n=16(18)=10m+4sm+2st;二苞黄精,2n=18=8m+10sm;黄精,2n=24=4m+8sm(2sc)+12st(2sc);卷叶黄精,2n=20=12m(2sc)+8sm。作者推测该属的染色体基数x=10。染色体数目进化的趋势是:非整倍性变异为主,整倍性变异为次;上升性变异为主,下降性变异为次。按照核型不对称程度,8个种的核型可分为三个等级。核型由对称向不对称进化是与染色体数目的进化趋势大体上相关的。     

四种野生百合核型分析

对南川百合(Lilium rosthornii Diels)、青岛百合(L.tsingtauense Gilg)、山丹(L.pumilum DC.)和岷江百合(L.regaleWilson)等4种野生百合进行了染色体数目观察和核型分析。结果表明,核型除山丹为3A外,其余3种材料核型均为3B。核型公式分别为:南川百合2n=2x=24=4m(4SAT)+2sm+6st+12t;青岛百合2n=2x=24=8m(4SAT)+2sm(2SAT)+14t;山丹2n=2x=24=2m(2SAT)+6sm(2SAT)+4st(4SAT)+12t;岷江百合2n=2x=24=2m(2SAT)+2sm+6st+14t。核型不对称系数分别是81.68%、76.09%、80.34%和82.26%。其中,南川百合和青岛百合为国内首次报道。     

白豆杉的核型和性染色体的研究

白豆杉pseudotaxus chienii(Cheng)Cheng是我国裸子植物特有属之一,雌雄异常,根尖 细胞染色体分析表明：雌株有一对异形性染色体,异配性别,属ZW型;雄株是同配性别,属ZZ型,雌株的型为2n=2x=24=22m(2SAT ZW) 2T,雄株的核型为2n=2x=24=22m(2SAT ZZ) 2T。Giemsa C-带,显示,Z染色体长短臂均具端带,W染色体不显带。     

Comparative cytogenetics of hamsters of the genus Calomyscus

Karyotypes of Calomyscus from different regions of Turkmenistan, Iran, and Azerbaijan were studied using chromosome banding (G- and C-banding) and analyses of meiosis in laboratory hybrids. Extensive variation in the diploid number and the number of autosomal arms (FNa) was revealed (2n = 30, FNa = 44; 2n = 32, FNa = 42; 2n = 44, FNa = 46; 2n = 44, FNa = 58; 2n = 37, FNa = 44; 2n = 50, FNa = 50; 2n = 52, FNa = 56). Centric and tandem fusions and heterochromatin changes were identified as the major modes of karyotype evolution in this group. Natural hybrids between individuals with different karyotypes were recorded, and regular chromosome pairing in meiosis was observed in laboratory hybrids. Fluorescence in situ hybridization with a 353-bp BspRI complex tandem repeat indicated that chromosomal repatterning occurred recently within the genus. There is no unequivocal evidence suggesting the role of chromosomal change in the speciation of the populations of Calomyscus examined.     

Constitutive heterochromatin DNA polymorphisms in diploid Medicago sativa ssp. falcata.

A Giemsa C-banding technique was used to study the amount and location of constitutive heterochromatin in diploid (2n = 2x = 16) Medicago sativa ssp. falcata (L.) Arcangeli. Most accessions had the standard C-banding pattern with centromeric bands on all the chromosomes and a prominent heterochromatic band at the nucleolar organizer regions (NOR) of the satellited (SAT) chromosomes. However, we observed in various accessions that constitutive heterochromatic C-bands can exist at the telomeric ends of all the chromosomes. Interstitial bands occurred on the short arms of all chromosomes except for chromosome 3 and on the long arms of chromosomes 1, 2, 3, and 6, only. Rearranged chromosomes such as isochromosomes have been observed for the short arms of chromosomes 2 and 6. This is the first report on the existence of C-banding polymorphisms and the detection of putative isochromsomes in the chromosomes of diploid ssp. falcata which could have contributed to the variation observed in cultivated alfalfa.     

Cytogenetic analysis of the neotropical spider Nephilengys cruentata (Araneomorphae, Tetragnathidae): standard staining nors, C-bands and base-specific fluorochromes.

The aim of this work is to characterize Nephilengys cruentata in relation to the diploid number, chromosome morphology, type of sex determination chromosome system, chromosomes bearing the Nucleolar Organizer Regions (NORs), C-banding pattern, and AT or GC repetitive sequences. The chromosome preparations were submitted to standard staining (Giemsa), NOR silver impregnation, C-banding technique, and base-specific fluorochrome staining. The analysis of the cells showed 2n = 24 and 2n = 26 chromosomes in the embryos, and 2n = 26 in the ovarian cells, being all the chromosomes acrocentric. The long arm of the pairs 1, 2 and 3 showed an extensive negative heteropycnotic area when the mitotic metaphases were stained with Giemsa. The sexual chromosomes did not show differential characteristics that allowed to distinguish them from the other chromosomes of the complement. Considering the diploid numbers found in N. cruentata and the prevalence of X1X2 sex determination chromosome system in Tetragnathidae, N. cruentata seems to possess 2n = 24 = 22 + X1X2 in the males, and 2n = 26 = 22 + X1X1X2X2 in the females. The pairs 1, 2 and 3 showed NORs which are coincident with the negative heteropycnotic patterns. Using the C-banding technique, the pericentromeric region of the chromosomes revealed small quantity or even absence of constitutive heterochromatin, differing of the C-banding pattern described in other species of spiders. In N. cruentata the fluorochromes DAPI/DA, DAPI/MM and CMA3/DA revealed that the constitutive heterochromatin is rich in AT bases and the NORs possess repetitive sequences of GC bases.     

中国两种波腿蝗（蝗总科：癞蝗科）染色体C带核型研究

报道中国两种波腿蝗的染色体C带核型,结果表明：红胫波腿蝗Asiotmethis zacharjini (Bei-Bienko, 1926) 2n ♂ =18, neo-X为亚中着丝粒染色体,其他均为近端着丝粒染色体,染色体除强染的着丝粒C带,S8染色体具强染端部C带带纹,neo-Y染色体还具有一条宽的弱染的近着丝粒端居间C带,性别决定机制是neo-XY ♂型,该种染色体组成和性别决定机制在我国癞蝗中为首次报道,蓝胫波腿蝗Asiotmethis jubatus (Uvarov, 1926) 2n＝19♂,均为近端着丝粒染色体,仅具有明显强染的着丝粒C带,性别决定机制是XO ♂型;两种波腿蝗的异染色质含量存在显著性差异（α=0.05）。     

Complex sex chromosome system in Eigenmannia sp. (Pisces,Gymnotiformes)

Chromosomes of Eigenmannia sp. (7 males and 15 females) collected from the Tietê River in Botucatu (SP, Brazil) were examined from gill, kidney and testicular cells. The diploid chromosome number in males was 2n=31 and in females, 2n=32. In both sexes the number of chromosomal arms was 40. The difference in diploid number was due to the fusion of two acrocentrics. Mitotic and meiotic studies suggested that one of the fused acrocentrics was the Y chromosome. The sex-determining mechanism in Eigenmannia sp. could therefore be XX, AA in the female and X, \-YA A in the males. One of the males presented 2n=30 chromosomes due to the occurrence of another fusion of acrocentrics. C-banding analysis of the mitotic chromosomes revealed constitutive heterochromatin in the centromeric regions of all acrocentrics. However, small metacentrics were C-band negative. The YA chromosome is C-band negative except for a small amount of heterochromatin in the centromeric region. The nucleolar organizer region as identified by Ag-staining is present in the interstitial region of chromosome pair No. 10.     

Banded karyotypes of mole rats (Spalax, Spalacidae, Rodentia) from Turkey: a comparative analysis

Chromosome banding (G-, C- and Ag-NOR) analysis was carried out on 27 specimens of Sphalax ehrenbergi from seven localities and two specimens of S. leucodon from one locality, all from Turkey. No chromosomal variation was detected in S. ehrenbergi populations from Elazig, Siverek, Diyarbakir and Birecik having the same diploid numbers (2n = 52) and morphology of chromosomes (NFa = 72). The karyotypes of mole rats from Tarsus and Gaziantep possessed the identical diploid number (2n = 56) but different numbers of autosomal arms: NFa = 68 in the Tarsus and NFa = 78 in the Gaziantep populations. Chromosomes of S. leucodon from Malaty (2n = 60, NFa = 74) differed distinctly in the C-banding pattern from all S. ehrenbergi cytotypes by the almost entire absence of heterochromatin in acrocentric autosomes and the presence of heterochromatin arms iin subtelocentric autosomes. Nucleolar organizing regions were found mainly on three pairs of chromosomes, but some differences in their localization were revealed. Comparison of G-banded chromosomes showed, that most chromosomes have a similar pattern. The types of chromosomal rearrangemetns were revealed due to the banding methods.     

Chromosome evolution by robertsonian translocation in Gibasis (Commelinaceae)

The plant species Gibasis schiedeana (Kunth) D. R. Hunt sens. lat. contains two cytotypes viz. a self-sterile diploid with 2n=10 (x=5) and a selffertile cytological autotetraploid with 2n=16 (x=4). Single chromosome sets of these plants consist of 2 metacentrics +3 acrocentrics, and 3 metacentrics +1 acrocentric chromosomes respectively suggesting a Robertsonian relationship between them. Their artificial F₁ hybrids show the pairing of acrocentrics with metacentric arms confirming the supposed nature of the chromosome affinities. Both breeding systems and ploidy levels show that the direction of the change has been from x=5 to x=4 by a translocation of the Robertsonian type.     

Characterization of Some Chromosomal Aberrations in Regenerated Rice Plants (<Emphasis Type="Italic">Oryza sativa</Emphasis>)

Somaclonal variation was studied in two Iranian land races of O. sativa spp. japonica var Hassani and O. sativa spp. indica var Sadridomsiah and 2000 plants of each cultivar were cytogenetically examined in two steps. In the first step, chromosome counts of root tips was used to detect ploidy levels and aneuploids of regenerated plants. In the second step, chromosomal aberrations were characterized by pachytene analysis of PMC’s. Ploidy levels were seen between n and 4n (haploids to tetraploids) in both cultivars with diploid resource (2n = 2x = 24). The total rate of variation for Hassani (japonica) was 13.7% including 10.8% for changes in chromosome number (ploidy levels and aneuploids) and 2.9% for chromosomal aberrations such as deficiency. A total rate of variation for Sadridomsiah (indica) was 15.6% including 12.4% for change in numbers and 3.2% for aberrations in construction. Most of important cytological mutations were observed in various chromosomes among regenerated plants of cultivars. Neither nullisomics nor inversions were distinguished in any samples.     

Evaluation of BC2 progenies derived from 3x-2x and 3x-4x crosses of Lilium hybrids: a GISH analysis

An allotriploid (ALA, 2n=3 x=36) BC(1) plant was obtained by backcrossing a diploid F(1) interspecific hybrid (LA, 2n=2 x=24), derived from a Lilium longiflorum (L genome) and an Asiatic hybrid (A genome), to the latter parent. This allotriploid was backcrossed to a diploid Asiatic hybrid (2n=2 x=24) and to an allotetraploid (LLAA, 2n=4 x=48) LA hybrid. A total of 25 plants of these crosses were examined for ploidy level, and 12 individuals were analyzed for their genome constitution through genomic in situ hybridization (GISH). In most cases the progenies from the triploid-diploid (3 x-2 x) crosses consisted of aneuploids. Further more, there was evidence for the formation of near-haploid (x=12+2) to triploid (3 x=36) gametes in the allotriploid BC(1) plant. The progenies of triploid-tetraploid (3 x-4 x) cross also consisted of mostly aneuploids but in this case the triploid female parent had contributed predominantly near-triploid (2n) gametes for the origin of BC(2) progenies. The different ploidy levels observed between 3 x-2 x and 3 x-4 x crosses are possibly caused by preferential fertilization or survival resulting in a different ratio of chromosome numbers between the embryo and endosperm. Though Lilium has a tetrasporic, eight-nucleate type of embryo sac formation (Fritillaria type), the observed difference between the progeny types in 3 x-2 x and 3 x-4 x crosses is comparable to that of observed in monosporic eight nucleate types (Polygonum type) that predominate in most genera of Angiosperms. An important feature of the genome constitution of the progenies was that the homoeologous recombinant chromosomes were transmitted intact from BC(1) to BC(2) progenies in variable numbers. In addition, there was evidence for the occurrence of new homoeologous recombinations in the triploid BC(1). Of the two euploid BC(2) plants one had originated through the parthenogenetic development of a 2n egg and the other had originated through indeterminate meiotic restitution (IMR).