麦蓝菜的花粉母细胞减数分裂及核型分析

采用压片法,对麦蓝菜的花粉母细胞减数分裂及体细胞核型进行了研究。结果表明,麦蓝菜的绝大多数花粉母细胞减数分裂中染色体的行为正常,在终变期同源染色体配对后可形成15个二价体;在少数花粉母细胞减数分裂中观察到落后染色体、染色体桥等异常行为;其减数分裂为同时型,其花粉粒育性为88.04%。麦蓝菜的染色体数目为2n=2X=30,核型公式为K(2n)=2X=30=22m(2SAT)+8 sm,染色体相对长度组成为2n=16M2+14M1,其核型为"1A"型。     

黄芩的花粉母细胞减数分裂及核型分析

采用压片法,对黄芩花粉母细胞减数分裂及核型进行了研究。结果表明:黄芩的大多数花粉母细胞减数分裂中染色体的行为正常,在终变期同源染色体配对后可形成9个二价体,后期Ⅰ染色体以9∶9的方式向细胞两极分离,其减数分裂为同时型;在少数花粉母细胞减数分裂中观察到落后染色体、染色体桥等异常行为;其花粉粒育性为76.49%。黄芩的染色体数目为2n=2X=18,核型公式为K(2n)=2X=18=16m+2 sm,染色体相对长度组成为2n=1 s+4M1+3M2+1L,其核型为"1A"型。     

浙江产7种菝葜的染色体研究

本文报道浙江产菝葜属smilax 7个种的染色体数目和核型。S．nipponica有两种核型,2n＝26和2n=32,均为3B型,但后一种细胞型的雄株的第一对染色体大小不等,可能为性染色体;S.riparia 2n=30,属3B型;S．siebodii n＝16;S. china有两个染色体数目,2n＝96 和n＝15;S. davidiana 2n=32,属3B型,对减数分裂MI的观察发现n＝16;S．glabra 2n=32,亦属3B型：S. nervo-marginata var．liukiuensis 2n=32,属3C型。讨论了种间在核型上的差异、属的基数、核型演化趋势和性染色体等问题。     

中间锦鸡儿(caranaga intermedia)染色体变异研究

对中间锦鸡儿(caranaga intermedia)种子根尖染色体进行检测,统计分析了染色体数目和结构变异类型.核型分析结果表明中间锦鸡儿正常核型为2n=2x=16=14m+2sm,还发现了核型公式为2n=2x=16+1B=1st+9m+2sm+1m(sAT)+1sm(SAT)+2m(SAT)+1B;核型公式为2n=2x=16+1B=6sm+8m+2m(SAT)+IB;以及核型公式为2n=2x=15=7sm+8m的变异类型.本研究首次发现了中间锦鸡儿存在B染色体和中间随体,此外还发现存在单体植株.随体具有个体差异,有中间随体和端部随体两种,且无论个体间和个体内B染色体均存在数目和结构的多态性.对其中120粒种子根尖染色体结果统计分析.发现具有15条染色体的植株占0.83%;具有16条染色体的植株占89.17%;具有17条染色体的植株占3.3%;具有18条染色体的植株占2,5%,其中有一个体中多于的一条染色体始终呈点状;19条染色体的植株占1.67%,5条多于染色体的占0.83%,而多余染色体条数在1～3之间变动的植株占1.67%.     

番木瓜核型和减数分裂研究

对番木瓜核型和花粉母细胞减数分裂行为的研究表明,番木瓜染色体数目为2n=18,由9对中部着丝粒染色体组成。核型公式为2n=2x=18m。花粉母细胞减数分裂正常,在终变期和中期Ⅰ观察到9个二价体,未观察到染色体结构变异和行为异常。     

苜蓿属3种不同花色基因型的染色体核型分析

基于形态学的显著差异,对紫花苜蓿(Medicago sativa L.)、黄花苜蓿(Medicago falcata L.)和白花苜蓿(Alfalfa with Cream flower)进行染色体核型分析,结果表明,3种类型的苜蓿材料在染色体核型方面有显著差别,白花苜蓿和黄花苜蓿都是随体染色体,其中,黄花苜蓿有2条为端部着丝点染色体,其核型公式分别为:紫花苜蓿2n=4x=24m+8sm、黄花苜蓿2n=4x=24m+6sm+2T(SAT)、白花苜蓿2n=4x=24m+8sm(SAT)。紫花苜蓿与白花苜蓿的染色体具有89%的相似性,只是在紫花苜蓿7号染色体和白花苜蓿15号染色体存在随体有无的区别;黄花苜蓿染色体具有独特性,显著区别于紫花苜蓿和白花苜蓿,但从其19号染色体来看,参与了紫花苜蓿或白花苜蓿的构建;白花苜蓿15号随体染色体与黄花苜蓿25号随体染色体和紫花苜蓿7号染色体有高度的相似性,但也存在随体有无的区别。     

秤锤树的核型研究及其减数分裂过程的观察

观察研究了秤锤树有丝分裂和减数分裂的细胞学特征。秤锤树核型为2n=2x=24=4m 7sm(2SAT) 1st,属于较为原始的2A型。有丝分裂间期核为复杂染色中心型,前期出现B染色体,中期染色体中等大小。减数分裂中期具12对正常的二价体,但后期I和后期Ⅱ均有染色体异常现象发生。统计断片、落后染色体和染色体桥出现的比例与花粉粒败育性比例比较一致,表明秤锤树的小孢子在发生和发育过程中较高频率的败育现象可能存存一常的细胞学原因．     

风毛菊属6种植物的核型分析

采用常规压片技术对分布于横断山区菊科(Compositae)风毛菊属(Saussurea DC.)的6种植物进行染色体数目和核型分析。结果表明:尖苞雪莲（S.polycolea var.acutisquama）核型公式为:2n=2x=32=20m+12sm,属2B型;球花雪莲核（S.globosa）型公式为:2n=2x=34=16m+18sm,属2B型;重齿风毛菊(S.katochaete)核型公式为:2n=2x=32=8m+18sm+6st,属3B型;柱茎风毛菊(S.columnaris)核型公式为:2n=2x=32=24m+8sm,属2B型;禾叶风毛菊(S.graminea)核型公式为:2n=2x=28=8m+18sm+2st,属3B型;长毛风毛菊(S.hieracioides)核型公式为:2n=2x=32=12m+16sm+4st,属2B型。6个种染色体中均未发现随体。其中尖苞雪莲和柱茎风毛菊染色体为首次报道。     

紫竹梅的减数分裂与核型分析

以紫竹梅根尖和花药为材料,分析鸭跖草科紫竹梅的染色体组型,并观察花粉母细胞减数分裂过程中的染色体行为。紫竹梅体细胞染色体数目为24,由12对中着丝粒染色体组成,核型公式为2n=2x=24m。花粉母细胞减数分裂正常,在第一次分裂中期观察到12个二价体,与观察到的体细胞染色体数目互相印证。     

埃塞俄比亚芥与芥蓝杂交获得异源三倍体及其细胞学研究

以埃塞俄比亚芥(2n=4x=BBCC=34)和芥蓝(2n=2x=CC=18)为材料,通过相互杂交获得了异源三倍体(2n=3x=BCC=26)。该异源三倍体生长势较强;叶色等介于双亲之间;株型、花型和花大小偏向于埃塞俄比亚芥;花色与芥蓝的相同,为白花。减数分裂观察表明:在终变期,一般形成9个二价体和8个单价体(9Ⅱ+8Ⅰ),且B、C两组染色体表现出一定程度的分群现象;中期Ⅰ,CC基因组的9个二价体排列在赤道板上,而B组的8个单价体游离在赤道板周围;后期Ⅰ分到两极的染色体以13/13和12/14占多数,偶见落后的染色体。该BCC异源三倍体的获得为创建CC+B染色体的异附加系和研究B、C基因组间的亲缘关系奠定了基础。     

Chromosome numbers of some species of Salvia (Lamiaceae) from the Sichuan Province, China

The present study reports the chromosome number of 12 accessions belonging to 10 species of Salvia from the Sichuan Province in China. Most accessions have the chromosome number 2n=2x=16. However, three species ( S. evansiana, S. przewalskii and S. brevilabra ) are tetraploid with a chromosome number of 2n=4x=32. A B-chromosome was observed in S. tricuspis . The basic chromosome number x=8 was inferred for all accessions studied. The chromosome number of all the species was determined for the first time, except for S. evansiana, S. przewalskii , S. flava and S. miltiorrhiza . The chromosomes in this genus are mostly small (0.46–2.94 μm). The small size of the chromosomes, together with their unclear centromeres, has hampered a detailed karyotype analysis.     

同源四倍体青花菜的核型分析

以四倍体青花菜为材料,采用常规压片法进行核型分析和有丝分裂观察.结果表明:四倍体青花菜核型公式为2n=4x=36=16m+20sm(4 SAT),其中第3、4、7、8对为中着丝粒染色体,第1、2、5、6、9对为近中着丝粒染色体,第6对染色体具随体;核型类型属于2A型,为基本对称型;染色体相对长度组成为2n=36=16 M_2+20 M_1,表明该四倍体青花菜是二倍体加倍得到,为同源四倍体.在部分四倍体根尖中发现非整倍体细胞,其染色体数目变异较大;与二倍体相比,四倍体有丝分裂过程存在双核仁、体细胞配对、染色体桥等异常现象.     

Karyotypic evolution of hapalomys inferred from chromosome painting: a detailed characterization contributing new insights into the ancestral murinae karyotype

We report on the construction of a comparative chromosome map between the emblematic laboratory rat, Rattus norvegicus (RNO), and Delacour's Marmoset rat, Hapalomys delacouri (HDE), based on cross-species fluorescence in situ hybridization with R. norvegicus painting probes. Sixteen R. norvegicus chromosomes (RNO 3-6, 8, 10-15, 17-20, and X) were retained in their entirety (as a conserved block or as a single chromosome) in the H. delacouri genome. The remaining 5 R. norvegicus chromosomes (RNO 1, 2, 7, 9, and 16) produced 2 signals in the H. delacouri karyotype. Our analysis allowed the detection of an X-autosome translocation between RNO X and 11 that occurred convergently in an unrelated species, Bandicota savilei, and a single B chromosome that accounts for the 2n = 48 karyotype observed in this specimen. In total, the rat chromosome paints revealed 27 segments of conserved synteny in H. delacouri. The analysis showed 7 NOR bearing pairs in H. delacouri (HDE 1, 3, 6, 7, 8, 10, and 13) and the occurrence of an interstitial telomeric signal at the centromeric regions of 8 H. delacouri chromosomes (HDE 3, 10, 11, 12, 13, 16, 19, and 22). These data, together with published comparative maps, enabled a revision of the previously postulated murine ancestral condition suggesting that it probably comprised a wholly acrocentric karyotype with 2n = 46-50.     

三尖叶猪屎豆染色体核型分析

本文以三尖叶猪屎豆(Crotalaria anagyroides H.B.K)根尖为试验材料,对其染色体核型及数目进行了研究。研究结果表明:三尖叶猪屎豆体细胞染色体数目为2n=16。染色体组总长度为26.62微米,全部的染色体为中部着丝点,除在第8对染色体上发现有一随体外,其余均没有发现随体和次缢痕。按Levan的染色体分类标准,其染色体核型组成是K(2n)=16=14m+2m_8~(sat)。     

黑线姬鼠华北亚种染色体研究

本文采用骨髓染色体制片法,对分布于山东的黑线姬鼠华北亚种的染色体组型,C-带、G-带和银染核型进行了分析研究。其核型为2n=48=38 T+8 M+XY。X为较小的端着丝粒染色体,Y为组型中最大的染色体。几乎每个常染色体的着丝粒区都具异染色质。性染色体的异染色质丰富。No.10和No.18染色体具NOR(?)。每条染色体都显示出较清晰的G-带。同时对黑线姬鼠精母细胞的减数分裂进行了观察,并将山东标本与欧洲标本的核型进行了比较,其性染色体有显著差异。     

A Study on Karyotypes of the Genus Lycoris

The genus Lycoris (Amaryllidaceae) consists of about 20 species, all of which are confined to temperate China, Japan and Korea. Cytological investigations, including a reexamination of the karyotypes of 14 taxa, measurements of relative nuclear DNA content, and meiotic configuration observations on some specific forms and interspecific hybrids, have been carried out by the present authors in order to re-evaluate the mode of karyotype evolution and the role of hybridization in the speciation of Lycoris. These have resulted in a new theory for explaining the karyotype evolution in the genus, which will be considered elsewhere. The present paper deals with observations on karyotypes of 11 species, 1 variety and 2 artificial hybrids. Results obtained through karyotype analysis, as shown by the data in Table 1, Plates I-VI and Figs. 1-2, reveal that: (1) the karyotypes of Lycoris rosea, L. radiata var. pumila, L. sprengeri, L. haywardii, L. caldwellii, L. squamigera and L. radiata are, on the whole, consistent with those reported by the previous authors^{[1,2,3,4,5,8,10,12]};(2) the I (rodshaped) chromosomes of L. chinensis and L. longituba are all T’s (telocentric) instead of t’s (acrocentric) or t(Sat)’s; (3) the three materials of L. aurea of different sources have shown a karyotypic differentiation: one with 2n=14=8m+6T, and the others with 2n=16=6m+10T: (4) both of the karyotypes of L. straminea and L. albiflora are 2n=19=3V+6I, inconsistent with 2n=16=6V+10I for the former and with 2n=17=5V+12I for the latter as reported by Inariyama (1953), Bose and Flory (1963) and Kurita (1987). The following aspects are worthwhile discussing: 1. The types of chromosomes. Karyotype analyses reveal the existence of three major chromosome types in Lycoris: (1) m (metacentric) chromosomes: (2) t (acrocentric) chromosomes, with short arms, (3) T (telocentric) chromosomes, sometimes with dot-like terminal centromeres. To distinghish t’s from T’s is of paramount importance for solving the problem of karyotype evolution in Lycoris. Bose (1963) pointed out that in the species with 2n=22, all I chromosomes were t’s, while in species with 2n=12-16, all I chromosomes were T’s. Our results of chromosome observations are consistent with Bose’s remarks. Some authorst^[3,6] have probably mistaken the dot-like terminal centromeres of T’s of L. longituba and L. chinensis as the short arms of t’s. 2. The significance of Robertsonian change in karyotype evolution. Although chromosome numbers and karyotypes are very variable in Lycoris, as shown in Table 1, the total number of arms of a chromosome complement of any species is always multiples of 11. Hence, it seems likely that Robertsonian changes have taken part in karyotype alteration, The genus has a series of basic chromosome numbers: 6, 7, 8 and 11. But which is the most primitive one? It is uncertain whether a successive decrease in chromosome numbers as a result of Robertsonian fusion or a gradual increase in chromosome numbers brought about by fission (fragmentation) has been the essential mechanism for karyotype evolution and speciation in Lycoris. These problems are of crucial importance and will be discussed in our subsequent papers. 3. The origin of polyploids. As evident from Table 1, there are two levels of ploidy differentiation in Lycoris: (1) di ploids with 2n=22 or the equivalent of 22, (2) triploids with 2n=33 or the equivalent of 33. The most common way of origination of triploids in plants is the hybridization of diploids with Tetraploids. But tetraploids have never been found in Lycoris. Thus, it is suggested that the triploids have originated from the combination of an unreduced gamete of a diploid with a normal gamete of another diploid. 4. The role of hybridization in speciation. Results of karyotype analyses show that hybridization has taken an important part in the speciation of Lycoris. Two types of hybrids have been found: (1) 2n=19= 3V+ 16I, L. straminea, L. albiflora and the two artificial hybrids L. sprengeri×L. chinensis and L. haywardii× L. chinensis all possess this karyotype. It could be seen from the above chromosome number and karyotype that this sort of karyotype is exactly half of the total sum of 2n=22I and 2n=16= 6V+10I. It is, therefore, quite evident that taxa possessing this karyotype are all diploid hybrids of 2n=22 and 2n=16, (2) 2n=27=6V+21I, L. caldwellii and L. squamigera possess this karyotype. It is reasonable to assume, too, that they are segmental allotriploids and have arisen from the combination of an unreduced diploid gamete of 2n=16 and a normal haploid gamete of 2n=22. The origin of the hybrid karyotype 2n=17=5V+12I reported by Inari- yama (1953) is similar to that of 2n=19, except that one of the parents possesses 2n=12= 10V+2I instead of 2n=16=6V+10I. The origin of the other hybrid karyotype 2n=30=3V+ 27I reported by Bose (1963) is similar to that of 2n=27, but the diploid gamete comes from taxa possessing 2n=22 instead of 2n=16.     

Karyotype Analysis of 5 Species of Polygonatum Mill.

The present paper reports the chromosome numbers and karyotypes of five species in Polygonatum from Anhui of China. The materials used in this work are listed in Table 1, Photomicrographs of somatic metaphase and karyograms of the five species of Polygonatum in Plate 1, 2, 3, the idiograms in Fig. 1-11 and a comparison of the karyotype of them is provided in Table 2. The results are shown as follows: 1. Polygonatum odoratum (Mill.)Druce Two materials were examined. One from Mt. Huangshan, Anhui, has 2n= 16 = 10m (3sc)+ 6sm (Plate 1 :A, B). The idiogram is shown in Fig. 1. The chromosomes range in length from 2.85 to 8.85 μm, with the total length 48.63μm and the ratio of the longest to the shortest 3.11, The karyotype belong to Stebbins’(1971) 2B. The two chromosomes of the first pair have arm ratios 1.01 and 1.29 respectively, and The first pair has one chromosome carrying a satellite attached to the short arm, showing heterozyosity .The chromosome num ber of 2n= 16 in P. odoratum and its karyotype are reported for the first time. The other from Langyashan, Chu - xian, Anhui, is found to have 2n = 18 = 10m (Isc)+2sm+6st(2sc) (Plate 1: C, D). The idiogram is shown in Fig. 2. The chromosomes range in length from 2.43 to 8.29μm, with the total length 46.67µm and the ratio of the longest to the shortest 3.41. The karyotype is also of 2B. In a somatic chromosome complement the 2nd pair have one chromosome carrying a satellite attached to the long arm, showing heterozygosity. 2. Polygonatum filipes Merr. Two materials were examined. One from the Huangshan, Anhui is found to have two cytotypes: 2n= 16 and 2n=22. This paper reports one of them. The karyotype formula is 2n=22=8m+8sm(2sc)+6st(Plate 3: Q, R). The idiogram is shown in Fig. 3. The chromosomes range in length from 2.55- 5.85μm, with the total length 45.01 μm and the ratio of the longest to the shortest 2.29. The karyotype belongs to 3B. The other material from the Fangchang, Anhui, is shown to have four cytitypes: 2n= 14, 2n= 16, 2n=20 (Plate 3: W) and 2n=22. This paper reports two of them. Type I: the karytype formula is 2n=14=10m+4sm (Plate 3: S, T). The idiogram is shown in Fig. 5. The chromosomes range in length from 2.59 to 7.61μm, the total length 37.44μm and the ratio of the longest to the shortest is 2.94. the karyotype belongs to 2B. Type II :The karyotype formula is 2n=16=8m+4sm+4st (Plate 3: U, V). The idiogram is shown in Fig. 4. The chromosomes range in length from 2.65 to 8.21 μm, the total length 46.01 μm and the ratio of the longest to the shortest 3.10. The karyotype belongs to 2B. The chromosome numbers of 2n=20, 2n= 14 and 2n=22, and karyotype of 2n= 14 and 2n=22 in P. filipes are reported for the first time. 3. Polygonatum cytonema Hua Two materials were examined. One from the Langyashan, Chuxian, anhui, is found to have 2n = 18 = 8m (2sc)+ 6sm+ 4st (Plate 2: K, L). The idiogram is shown in Fig. 7. The chromosomes range in length from 3.41 to 9.21 μm, the total length 56.34μm and the ratio of the longest to the shortest is 2.70. The karyotype belongs to 2B. The other material from the Huangshan, Anhui, has two cytotypes: 2n=20 and 2n= 22. Type I: The karyotype formula is 2n= 20= 8m+ 6sm+ 6st (Plate 2: M, N). The idiogram is shown in Fig. 8. The chromosomes range in length from 1.75 to 5.03μm, with the total length 32. 91μm and the ratio of the longest to the shortest 2. 87. The karyotype is also of 2B. Type II: The karyotype formula is 2n=22=6m+ 8sm+4st+ 4t (Plate 2: O, P ). The idiogram is Shown in Fig. 10. The chromosomes range in length from 1.75 to 4.95 μm, with total length 35.05μm and the ratio of the longest to the shortest 2.83. The karyotype brlongs to 3B. 4. Polygonatum desoulayi kom. The material from Xuancheng, Anhui, is found to have karyotype 2n = 22 = 10m (2sc) + 6sm (lsc) + 6st ( Plate 2. I, J). The idiogram is shown in Fig. 6. The chromosomes range in length from 1.86 to 5.61μm, with the total length 41.98μm and the ratio of the longest to the shortest 3.02. The karyotype is also of 3B. The first pair has one chromosome carrying a satellite attached to the long arm, showing heterozygosity. The chromosome number and karyotype of Chinese material are reported for the first time. 5. Polygonatum verticillatum (L.) All. The material from the Langyashan, Chuxian, Anhui is found to have two cytotypes. Type 1: the karyotype formula is 2n = 18 = 2m+ 2sm+ 10st+ 2t+ 2T (Plate 1: G, H). The idiogram is shown in Fig.9. The chromosomes range in length from 1.86 to 4.03μm, with total length 28.28μm and the ratio of the longest to the shortest 2.17. The karyotype classification belongs to 3B. Type II: The karyotype formula is 2n=24=6m+4sm+12st+2T (Plate 1: E, F). The idiogram is shown in Fig. II. The chromosomes range in length from 2.01 to 5.03μm, with total length 41.36μm and the ratio of longest to shortest 2.50. The karyotype is also of 3B. The chromosome numbers and karyotypes of Chinese material are reported for the first time.     

Chromosome evolution in kangaroos (Marsupialia: Macropodidae): cross species chromosome painting between the tammar wallaby and rock wallaby spp. with the 2n = 22 ancestral macropodid karyotype.

Marsupial mammals show extraordinary karyotype stability, with 2n = 14 considered ancestral. However, macropodid marsupials (kangaroos and wallabies) exhibit a considerable variety of karyotypes, with a hypothesised ancestral karyotype of 2n = 22. Speciation and karyotypic diversity in rock wallabies (Petrogale) is exceptional. We used cross species chromosome painting to examine the chromosome evolution between the tammar wallaby (2n = 16) and three 2n = 22 rock wallaby species groups with the putative ancestral karyotype. Hybridization of chromosome paints prepared from flow sorted chromosomes of the tammar wallaby to Petrogale spp., showed that this ancestral karyotype is largely conserved among 2n = 22 rock wallaby species, and confirmed the identity of ancestral chromosomes which fused to produce the bi-armed chromosomes of the 2n = 16 tammar wallaby. These results illustrate the fission-fusion process of karyotype evolution characteristic of the kangaroo group.     

角堇与大花三色堇染色体核型分析

以2份角堇与4份大花三色堇自交系为试验材料,采用染色体常规压片方法,观察和分析了它们的细胞染色体数目、相对长度、平均臂比等核型指标,以明确两种植物细胞学特点,为分类以及育种提供理论依据。结果表明:(1)2份角堇自交系染色体数目均为2n=2x=26,染色体基数为x=13,染色体核型公式分别为2n=2x=26=8m+12sm+6st、2n=2x=26=4m+16sm+6st,核型不对称系数为67.20%~70.10%,核型分类均属于3B。(2)4份大花三色堇自交系均为四倍体,其中2份(EYO-1-2-1-4、DSRFY-1-1-2)染色体数目为44,核型公式为2n=4x=44=4m+16sm+6st、2n=4x=44=16m+24sm+4st;2份(G10-1-3-1-4、XXL-YB-1-1-1-1)染色体数目为48,核型公式分别为2n=4x=48=8m+20sm+20st、2n=4x=48=4m+36sm+8st,核型不对称系数为66.74%~71.77%,核型分类属于2B、3B。