Phyletic and evolutionary relationships ofBrachyscome lineariloba (Compositae)

A comparison of karyotypes ofBrachyscome breviscapis (2n = 8),B. lineariloba cytodemes E (2n = 10), B (2n = 12) and C (2n = 16) suggests that these species have a homoelogous basic set of four chromosome pairs, two large pairs and two small, and that theB. lineariloba cytodemes E, B and C are related toB. breviscapis by successive additions of small chromosomes. A pronounced asynchrony of chromosome condensation between these large and small chromosomes has been observed. In the artificial hybrids betweenB. dichromosomatica (2n = 4) ×B. breviscapis, and theB. lineariloba cytodemes, theB. dichromosomatica chromosomes are similar in size and condensation behaviour to the small chromosomes ofB. breviscapis and ofB. lineariloba cytodemes E, B and C. Meiotic pairing in these hybrids also demonstrates the strong affinities between these chromosomes. It is suggested thatB. breviscapis may be of amphidiploid origin between a species with two large early condensing chromosome pairs and another,B. dichromosomatica-like species with two small late condensing pairs. It seems most likely that the additional small and late condensing chromosomes inB. lineariloba cytodemes E, B and C are derived from theB. dichromosomatica-like parent, and that each addition increases vigour, fecundity and drought tolerance, allowing these cytodemes to colonize more open and arid environments. Transmission of the univalents in the quasidiploidB. lineariloba cytodeme E was verified as being via the pollen, and not via the embryo sacs.The cytology ofBrachyscome lineariloba (Compositae, Asteroidae), 10.     

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。     

Cytogenetic analysis of the tamaraw (Bubalus mindorensis): a comparison of R-banded karyotype and chromosomal distribution of centromeric satellite DNAs, telomeric sequence, and 18S-28S rRNA genes with domestic water buffaloes

The karyotype of the tamaraw (Bubalus mindorensis, 2n = 46) was investigated by RBG-banding technique and compared with those of the river and the swamp cytotypes of domestic water buffalo (B. bubalis). The tamaraw karyotype consisted of 6 submetacentric and 16 acrocentric autosome pairs (NAA = 56), and X and Y chromosomes. The RBG-banded karyotype of the three taxa had a high degree of homology, and the tamaraw karyotype could be explained by a Robertsonian translocation between chromosomes 7 and 15 and by a telomere-centromere tandem fusion between chromosomes 4p and 12 of the standardized river buffalo cytotype (2n = 50, NAA = 58). The buffalo satellite I and II DNAs were localized to the centromeric regions of all the tamaraw chromosomes. The biarmed chromosome 2 of the tamaraw resulting from the fusion between chromosomes 7 and 15 of the standard contained much larger amounts of the satellite I DNA than the other biarmed chromosomes, suggesting that this chromosome was formed by a relatively recent Robertsonian fusion. The (TTAGGG)n telomeric sequence was specifically localized to the telomeric region of all the buffalo chromosomes. The 18S + 28S rDNA was localized to the telomeric regions of the chromosomes 5p, 7, 19, 21, and 22 of the tamaraw and of their homologous chromosomes in the river and swamp buffalo cytotypes.     

Synthesis and cytological characterization of trigeneric hybrids involving durum wheat,Thinopyrum bessarabicum,and Lophopyrum elongatum

Summary In an attempt to transfer genes for salt tolerance and other desirable traits from the diploid wheatgrasses, Thinopyrum bessarabicum (2n=2x=14; JJ genome) and Lophopyrum elongatum (2n=2x=14; EE genome), into durum wheat cv Langdon (2n=4x=28; AABB genomes), trigeneric hybrids with the genomic constitution ABJE were synthesized and cytologically characterized. C-banding analysis of somatic chromosomes of the A, B, J, and E genomes in the same cellular environment revealed distinct banding patterns; each of the 28 chromosomes could be identified. They differed in the total amount of constitutive heterochromatin. Total surface area and C-banded area of each chromosome were calculated. The B genome was the largest in size, followed by the J, A, and E genomes, and its chromosomes were also the most heavily banded. Only 25.8% of the total chromosome complement in 10 ABJE hybrids showed association, with mean arm-pairing frequency (c) values from 0.123 to 0.180 and chiasma frequencies from 3.36 to 5.02 per cell. The overall mean pairing was 0.004 ring IV + 0.046 chain IV + 0.236 III + 0.21 ring II + 2.95 rod II + 20.771. This is total pairing between chromosomes of different genomes, possibly between A and B, A and J, A and E, B and J, B and E, and J and E, in the presence of apparently functional pairing regulator Ph1. Because chromosome pairing in the presence of Ph1 seldom occurs between A and B, or between J and E, it was inferred that pairing between the wheat chromosomes and alien chromosomes occurred. The trigeneric hybrids with two genomes of wheat and one each of Thinopyrum and Lophopyrum should be useful in the production of cytogenetic stocks to facilitate the transfer of alien genes into wheat.     

风毛菊属5种植物的核型分析

采用常规压片法,对风毛菊属(Saussurea)5种植物的染色体数目和核型类型进行分析。结果表明:大耳叶风毛菊(S.macrota)核型公式为2n=2x=26=10m+12sm+4st,属2A型;长梗风毛菊(S.dolichopoda)核型公式为2n=2x=26=14m+8sm+4st,属2A型;川陕风毛菊(S.licentiana)核型公式为2n=2x=28=12m+16sm,属2B型;杨叶风毛菊(S.populifolia)核型公式为2n=2x=28=6m+18sm+4st,属2B型;尾叶风毛菊(S.caudata)核型公式为2n=2x=30=14m+14sm+2st,属2A型。这5种风毛菊属植物中,除大耳叶风毛菊染色体数目和核型类型与前人报道的一致外,其余4种植物的染色体数目和核型类型均为首次报道,并在川陕风毛菊中发现1对B染色体。     

Karyotypic characterization by mitosis, meiosis and C-banding of Eriopis connexa Mulsant (Coccinellidae: Coleoptera: Polyphaga), a predator of insect pests

Eriopis connexa presents a chromosome number of 2n = 18 + XX for most females analyzed and a meioformula of n = 9 + Xyp for all males. A small metacentric B chromosome restricted to females occurred in 10% of our sample and, when submitted to C-banding, it was shown to be almost completely euchromatic. Chromosome pairs 2 and 3 had satellites and probably contained the nucleolar organizer regions (NORs). C-band analysis also revealed that the constitutive heterochromatin was localized in the centromeres of all chromosomes in the complement.     

Variation of Giemsa C-band and fluorochrome banded karyotypes,and relationships inAllium subgen.Molium

The somatic karyotypes of 10 taxa belonging toAllium subgen.Molium (Liliaceae) from the Mediterranean area have been investigated using Giemsa C-band and fluorochrome (Hoechst, Quinacrine) banding techniques. A wide range of banding patterns has been revealed. InAllium moly (2n = 14),A. oreophilum (2n = 16) andA. paradoxum (2n = 16) C-banding is restricted to a region on each side of the nucleolar organisers and the satellites show reduced fluorescence with fluorochromes. The satellites are also C-banded and with reduced fluorescence inA. triquetrum (2n = 18), but two other chromosome pairs also have telomeric bands which are not distinguished by fluorochrome treatment. InA. erdelii (2n = 16) 4 pairs of metacentric chromosomes have telomeric C-bands while 2 pairs of telocentric chromosomes have centromeric C-banding. InA. subhirsutum (2n = 14),A. neapolitanum (2n = 28),A. trifoliatum subsp.hirsutum (2n = 14) andA. trifoliatum subsp.trifoliatum (2n = 21) chromosomes with long centromeres, consisting of a centromere and nucleolar organiser are positively C-banded on each side of the constriction. InA. subhirsutum banding is confined to the pair of chromosomes with this feature, whereas inA. neapolitanum one additional chromosome pair has telomeric bands and inA. trifoliatum there are varying numbers of chromosomes with centromeric and telomeric bands, depending on the subspecies.A. zebdanense (2n = 18) shows no C-bands. The banding patterns in this subgenus are compared with those recorded for otherAllium species and with the sectional divisions in the genus. Evidence from the banding patterns for allopolyploidy inA. trifoliatum subsp.trifoliatum andA. neapolitanum is discussed.     

Cytotaxonomical Studies on Liliaceae (s.l.): (2) Report on Chromosome Numbers and Karyotypes of 8 Species of 8 Genera from Zhejiang,China

Eight species in eight genera of Liliaceae from Zhejiang were cytotaxonomically studied in this work. The karyotypes of Chinese materials of these species are mostly reported for the first time. The results are shown as follows (see Table 2-4 for chromosome parameters of them): 1. Disporum sessile D. Don Sixteen chromosomes are counted at metaphase of roottip cells.The Karyotype formula is 2n=16=2lm+2sm+4st+2sm+3sm+ 1sm(SAT)+2st (Plate 1: 2-3, see Fig. 1:1 for its idiogram). The Karyotype belongs to 3B in Stebbins’ (1971) karyotype classification, and consists of four pairs of larger chromosomes (1-4) and four pairs of smaller chromosomes (5-8). One SAT-chromosome is situated at the sixth pair. The chromosomes range between 4.85-16.63μm. The karyotypic constitution is similar to that of Japanese material reported by Noguchi (1974). Chang and Hsu (1974) reported 2n=14=13st+1sm and 2n= 16=2m + 13st + 1sm for the material from Taiwan under the name of D. shimadai Hay. (=D. sessile D. Don). Compared with our result of D. sessile, the differences are obvious. 2. Polygonatum odoratum (Mill.) Druce PMCs diakinesis shows eleven bivalents, n = 11, 5 large and 6 small (Plate 2:5). The meiosis is normal. The majority of reports of this species are 2n=20, with a few 2n=22 and 30 (see Table 1). The materials from southen Siberia and the Far East in USSR are all of 2n= 20. Our result is the same as recorded by Jinno (1966) in the Japanese material and by Li (1980) from Beijing. Ge (1987) reported 2n=20 in the cultivated individuals of Shandong, China, showing that both 2n=20 and 22 exist in China. 3. Scilla scilloides (Lindl.) Druce This species has the somatic chromosome number 2n=18 (Plate 1: 4-6, see Fig. 1:2 for its idiogram), of which two groups of chromosomes can be recognized, i.e. the 1 st -5 th pairs of large and the 6 th-9th pairs of small chromosomes. A distinct character of the karyotype is that two satellites are attached to the short arms of the 1st pair of chromosomes. The degree of asymmetry is of 3C. The karyotype formula is 2n = 18 = 2sm (SAT) + 6st + 2t+ 6m + 2sm. The chromosomes range from 2.02 to 11.93 μm. The Previous counts on the species are 2n = 16, 18, 26, 34, 35, 36 and 43 (see Table 1). The present investigation confirms Noda’s and Haga’s results. The species is considered to be of two genomes, namely A(x = 8) and B(x = 9). Our result shows a genome composition of BB, having a pair of large SAT-chromosomes. Chang and Hsu (1974) reported 2n = 34 from a population of Taiwan, an amphidiploid (AABB), Karyotypes of other Chinese populations are worth further researches. 4. Tricyrtis macropoda Miq. The chromosome number of somatic cells is 2n= 26, and PMCs MII shows 13 bivalents (n= 13) (Plate 3:1-3, see Fig. 1:3 for its idiogram). The karyotype formula is 2n= 26= 6m + 10sm + 6st + 4st (or t), which is composed of chromosomes: 4L + 22S in size. The degree of asymmetry is of 3B. No centromeres of the 12th and 13th pairs of chromosomes were observed at metaphase, and the chromosomes may be of st or t. Nakamura (1968) reported 2n= 26(4L+ 22S)= 2sm+ 2sm-st+ 14st-sm+ 8st for T. macropoda Miq. and 2n= 26(4L+ 22S)= 8m+ 2sm+2sm-st+ 2st-sm+ 12st for its ssp. affinis, both from Japan. It is clear that the major character of their karyotypes, i. e. 4L + 22S, is consistent with that reported here. Based on the previous and present reports, all Tricyrtis species studied are remarkably uniform in the basic karyotype, i. e. 4L + 22S. 5. Allium macrostemon Bunge. The present observation on the root-tip cells of the species shows 2n = 32 (Plate 3: 4-5, see Fig. 1:4 for its idiogram). The karyotype formula is 2n (4x)= 32= 26m + 6sm, which belongs to 2B, being of high symmetry. Except the 6th, 10th and 13th pairs of chromosomes all the are metacentric. Chromosomes of this species are large, ranging from 5.94 to 18.06 μm. Our result agrees with Kawano’s (1975) report under the name of A. grayi Regel ( = A. macrostemon, Wang and Tang 1980). 6. Asparagus cochinchinensis (Lour.) Merr. Ten bivalents were observed in PMCs MI, n=10 (Plate 1: 1). The present result confirms the number of a population of Taiwan recorded by Hsu (1971). 7. Ophiopogon japonicus (L. f.) Ker-Gawl. The species from Mt. Taogui, Hangzhou, is found to have 2n (2x)=36=22m + 14sm (Plate 2: 1,5, see Fig. 1:5 for its idiogram) which belongs to 2B. The karyotype is composed of 2 medium-sized chromosomes with metacentric centromeres and 34 small chromosomes, ranging from 1.34 to 4.92 μm. The populations from Mt. Tianzhu and Mt. Yuling, Zhejiang, are found to be aneuploids at tetraploid level (2n=64-70). It is interesting that Nagamatsu (1971) found the karyotypes of Japanese materials to be 2n= 67 and 68, also showing unsteady 4x karyotypes of this species. In the previous. reports (see Table 1), the chromosome numbers of this species are mainly 2n = 72, besides 2n = 36 recorded by Sato (1942) from Japan. 8. Liriope platyphylla Wang et Tang The somatic complement of the species collected from Mt. Tianzhu, Hangzhou, is 2n = 36 (Plate 2: 3-4, see Fig. 1:6 for its idiogram). The karyotype is 2n(2x) = 36 = 16m + 20sm, belonging to 2B type. The chromosomes are small except the medium-sized, 1st pair and the range is from 1.27 to 5.19μm. The material from Mt. Yuling, Zhejiang, is found to have a variety of chromosome numbers (2n= 60-71), as observed in Ophiopogon japonicus. Hasegawa (1968) reported the karyotype of 2n = 72 (4x) from Japan The 2x karyotype is first recorded. This genus is closely related to Ophiopogon. Based on the Hasegawa’s and present studies, all the species in these two genera are remarkably uniform in karyo-type. Therefore, the taxonomy of the two genera is worth further researches.     

黄鳝体内寄生胃瘤线虫的染色体核型及G-带分析

采用常规空气干燥法制片,对寄生于黄鳝(Monopterus albus)体腔内的胃瘤线虫(Eustrongylidesignotus)染色体核型进行分析。结果表明:胃瘤线虫体细胞有12条染色体,为二倍体,核型公式为2n=12=10 m+2 sm。由5对常染色体和1对性染色体组成,性别决定模式为XX-XY,其中X、Y和1～4号染色体都为中着丝粒染色体,5号为亚中着丝粒染色体。每对染色体都有特定的G-带带型。     

Chromosomes of Six Fabaceous Species from Baoxing County,Sichuan Province

Meiosis and/or mitosis of six species of Fabaceae (Leguminosae) from Baoxing County, Sichuan, China, were investigated. The voucher specimens are conserved in PE. Eight pairs (n=8) and 10 chiasmata in meiosis of pollen mother cells have been observed in Medicago lupulina L. (Pl. 1, A-C). Meiotic observation on pollen mother cells in Lotus tenuis W. et K. shows 6 bivalents (n=6) in MI and 9 chiasmata in diakinesis (Pl. 1, D-E). In this species 12 somatic chromosomes (2n=12) in anther wall cells have also been observed. The chromosomal formula may be expressed as 2n=12=8m+2sm+2sm^SAT (Pl. 1, F-G). In pollen mother cells of Vicia tetrasperma (L.) Schreb., 7 bivalents in MI and 7 chromosomes in A II have been observed (Pl. 2, A-B). From A II (Pl. 2, B, the inset on the right) the chromosomal formula, n=7= 2m+2sm+lst^SAT+2t, may be constructed. Only three chromosomes in this karyotype may be found to have counterparts in the one reported by Srivastava (1963), which shows striking differences between these two karyotypes. Meiotic MI shows 7 pairs (n=7) in Vicia hirsuta (L.) S. F. Gray. Vicia sativa L. is very variable in its chromosomes. Our observation shows 6 pairs (n=6) in MI and in diakinesis in pollen mother cells. In Vicia villosa Roth, all the previous chromosome reports are 2n=14 or n=7, but the result of our work shows that somatic chromosomes are 2n=12 in anther wall cells (Pl. 3, D, E). The karyotype in our material (Pl. 3, E) is that the longest pair of chromosomes are metacentric, the pairs 2-4 are terminal, 5 are metacentric and last pair are submetacentric, differing vastly from the idiogram (Pl. 3, F) presented by Yamamoto (1973). Therefore both the chromosome number and structure in our material are greatly different from those in all the previous reports. The evolutionary trends of chromosomes in the genus Vicia is discussed in the work. Srivastava (1963) holds that the primitive basic number of chromosome in the genus is 6 and thus both 5 and 7 are derived. The present author would propose another possibility that 7 is the original basic number and the other numbers are derived ones. First, as shown in Table 1, x=7 occurs in 47 per cent of species in the genus, but 6 only in 28 per cent. Secondly, x=7 is predominant in the perennial and primitive section Cracca. Thirdly, in genera related to the genus under consideration, such as Lens, Pisum and Lathyrus, x=7 is also the predominant basic number. Fourthly, according to Raven (1975) 7 is the primitive basic number in the angiosperms and x= 7, 8 and 9 are the predominant in the angiosperms.     

Karyotypes of Rana tagoi Okada with diploid number 28 in the Chausu Mountains of the Minamishinshu district of Nagano Prefecture, Japan (Anura: Ranidae)

Karyotypes of Tago's brown frog Rana tagoi from the Chausu mountains in Minamishinshu of Nagano Prefecture were examined by conventional Giemsa staining, C-banding and late replication (LR)-banding. Chromosome number was 2n = 28 in all cases. The 28 chromosomes consisted of four pairs (1-4) of large biarmed chromosomes, two pairs (5-6) of telocentric chromosomes and eight pairs (7-14) of small biarmed chromosomes. Chromosome pair 11 had a secondary constriction on the long arm. In females, the C-band on the long arm of chromosome pair 6 was detected in both homologs, but was absent from the arms of the homologs of chromosome pairs 5 and 9. In males, C-bands were found in the long arms of both homologs of chromosome pairs 5 and 6, were present only in one homolog of chromosome pair 5 for certain male specimens and found in only one homolog of chromosome pair 9. Specimens of R. tagoi (2n = 28) should thus have two pairs of telocentric chromosomes to provide the same number of chromosome arms, these originating quite likely from chromosome pair 1 in the 26-chromosome specimens by centric fission. Heteromorphic sex chromosomes of the XX-XY type in R. tagoi (2n = 28) in the Chausu mountains were identified. Karyotypes of tail-tip cells from a hybrid tadpole between female R. tagoi (2n = 26) from the Hinohara village in Tokyo and male R. tagoi (2n = 28) from the Chausu mountain population were examined by squash preparation. Chromosome number was 2n = 27 in all tadpoles. The 27 chromosomes consisted of one chromosome set of R. tagoi (2n = 28) and one of R. tagoi (2n = 26).     

Karyotype analyses in three Patagonian and S. Andean endemic genera ofNicotianeae (Solanaceae)

The somatic chromosomes and karyotypes of threeNicotianeae have been studied for the first time. All of them have 2n = 2x = 22 and symmetrical karyotypes.Benthamiella pycnophylloides has 9 m pairs + 1 sm pair + 1 st pair; pairs 2, 4, 5, and 11 bear microsatellites.Combera paradoxa andPantacantha ameghinoi have 9 m pairs + 2 sm pairs; pair 11 ofC. paradoxa is satellited, while pair 9 ofP. ameghinoi bears microsatellites and shows a pericentric inversion in heterozygous state in 20% of the seedlings. Results are compared with previous chromosome reports for the tribe. The cytological data support their present position in the family system. Besides,Benthamiella, Combera andPantacantha appear to be primitive genera ofNicotianeae, a comparatively advanced tribe within the family.Chromosome studies onNicotianeae (Solanaceae) 1.     

Chromosome evolution within theOrnithogalum tenuifolium complex (Hyacinthaceae), with special emphasis on the evolution of bimodal karyotypes

Hypotheses on the evolution of the karyotypes of 8 chromosome races (2n = 4, 6, 8, 10, 12, 16-two forms, 26) within theOrnithogalum tenuifolium complex are discussed. Four of the karyotypes are strictly bimodal: 2n = 8 (6 long and two short chromosomes), 2n = 10 (6 long and 4 short chromosomes), 2n = 12 (6 long and 6 short chromosomes) and 2n = 16 (12 long and 4 short chromosomes). The hypotheses are tested by means of measurements of nuclear DNA content, studies of meiosis and pollen fertility of hybrids, and comparisons of karyotype morphology. The results indicate that the E. African 2n = 12 chromosome race is the most primitive and has given rise to the other chromosome races. The 2n = 6 race is found to have a significantly higher fitness than the 2n = 12 race.     

Comparative karyotype analysis in Haplopappus Cass. and Grindelia Willd. (Asteraceae) by double FISH with rRNA specific genes

The genera Grindelia Willd. and Haplopappus Cass. belong to the family Asteraceae - Astereae and are distributed in America and South America, respectively. Previous cytotaxonomic studies showed for South American species of Grindelia 2n=12 and for Haplopappus 2n=10 and 2n=12. Both Grindelia species (G. anethifolia, G. prunelloides), newly analyzed with molecular-cytological methods, exhibited symmetric karyotypes (AsI %=55.46 and 55.95) with metacentric chromosome sets (5m + 1m-sat) and 2n=12 chromosomes. The NOR was detected after fluorescence in situ hybridization (FISH) with 18/25S rDNA in the satellite chromosome 2. In contrast H. Happlopappus glutinosus, H. grindeloides and H. stolpii showed exclusively a higher asymmetric index (66.83%, 67.01% and 68.87%, respectively) with submetacentric chromosome sets (4sm + 1sm–sat). The sat-chromosomes 3 of H. glutinosus and H. grindelioides were both significantly different in their length from chromosomes 2 and 4. Furthermore in Grindelia the FISH with 5S rDNA could estimate signals in the short arms of chromosomes 3 or 4, that were not significantly differentiated in their length. Contrary to these findings in Grindelia, the position of 5S rDNA in Haplopappus was detected in the long arms of chromosome 1 (H. grindelioides and H. stolpii) and chromosome 2 (with two different loci) and chromosome 4 of H. glutinosus. The lengths of all measured chromosome arms with 5S rDNA were significantly different to those of the neighbours in the karyotypes. The two-color FISH of 5S and 18/25S rDNA had provided clear karyotypic markers for three (Haplopappus glutinosus) and two (H. grindelioides and H. stolpii) chromosomes. The number and position of rDNA signals were relatively highly conserved in the investigated five species without the double marked chromosome 2 of H. glutinosus, which shows an evolutionary dynamic of this 5S rRNA specific gene cluster. This investigation supports the assumption that the evolution of New World members of Grindelia and Haplopappus has not been accompanied by large karyotypic changes, but small chromosomal rearrangements have undoubtedly occurred (e.g. 5S rDNA localizations).     

Report on Karyotypes of 10 Species of Liliaceae (s. l.) From Qinling Range

The karyotypes of 10 species of the Liliaceae from the Qinling Range are reported as follows. I. Polygonatum Mill. (1) P. odoratum ( Mill. ) Druce was found to have the karyotype 2n=20=12m+8sm ( Plate 3, Fig. I), which belongs to Stebbins’ (1971) karyotype classification 2B. The chromosomes range from 3.88 to 11.26μm in size. Table 2 shows the karyotypes and number fundamentals (N.F.) of 13 materials from 12 different localities. The N. F. of these materials can be classified into two groups: N.F. =36 and N.F.=40, besides one (N.F. =38) from Beijing. N. F. =36 covers all the materials with 2n= 18 which have relatively symmetrical karyotypes ( all consisting of m and sm chromosomes), one with 2n=20 (10m+6sm+4st) and one with 2n=22 (14m+8st). N.F. =40 include four materials with 2n= 20 (all of m and sm chromosomes ) and 3 with 2n= 22 (10m+ 8sm+ 4st). ￥ It is considered that there are two original karyotypes, 2n= 18 with N. F. = 36 and 2n= 20 with N.F. =40, which are relatively symmetrical. All the more asymmetrical karyotypes with some st chromosomes have probably evolved from the symmetrical karyotypes without st chromosomes by centric fission. (2) P. zanlanscianense Pamp. has the karyotype 2n=30=18m(2SAT) + 4sm+ 6st+ 2t (Plate 1, Fig. 1) which belongs to 2C. The chromosomes range from 2.16 to 9.76μm. ￥ II. Asparagus filicinus Buch.-Ham. ex D.Don. The karyotype of this species is 2n = 16= 8m(2SAT )+ 6sm + 2st (Plate 1, Fig. 1 and Table 3 ) , which belongs to 2B. The chromosomes range from 2.33 to 5.30μm. Most species in Asparagus, including A.Filicinus, are reported to have basic number x= 10, and therefore 2n= 16 is a new chromosome number for A.filicinus. EL-Saded et.al.(1972) gave a report of n=8 for A. stipularis from Egypt, while Delay (1947) reported 2n = 24 for A. trichophyllus and A. verticillatus, Sinla(1972 ) gave a report of 2n=48 for A.racemosus. It is certain that there are two basic numbers in the genus Asparagus. III. Cardiocrinum giganteum (Wall.) Makino was found to have the karyotype 2n=24=4m+8st+12t (Plate 1, Fig. 1 ), which belongs to 3B. The chromosomes range from 8.71 to 20.24μm. IV. Smilax discotis Warb. was shown to have the karyotype 2n=32=4m+22sm+4st (2SAT)+2t (Plate 1, Fig. 1 and Table 3), which belongs to 3C. The first pair is much longer than others. The chromosomes range from 1.79 to 9.21μm. The chromosome number and karyotype of S. discotis are both reported for the first time. V. Reineckia carnea (Andr.) Kunth is of the karyotype 2n=38=28m+10sm (Plate 2, Fig. 1 ), which belongs to 2B. The chromosomes range from 5.65 to 12.75μm. VI. Tupistra chinensis Baker was found to have the karyotype 2n=38=25m+ 13sm (Plate 2, Fig. 1), which belongs to 2B. The chromosomes range from 8.11 to 23.82μm. A pair of heterozygous chromosomes is arranged at the end of the idiogram. The eighth pair possesses an intercalary satellite. Huang et al. (1989) reported the karyotype of T. chinensis from Yunnan as 2n = 38 = 24m+ 14sm without any intercalary satellite. Nagamatsu and Noda (1970) gave a report on the karyotype of T. nutans from Bhutan, which consists of 18 pairs of median to submedian chromosomes and one pair of subterminal chromosomes. And one pair of submedian chromosomes possess intercalary satellites on their short arms. VII. Rohdea japonica (Thunb) Roth. was found to have the karyotype 2n=38=30m+6sm+2st ( Plate 2, Fig. 1), which belongs to 2B. The chromosomes range from 7.94 to 18.29μm. Nagamatsu and Noda (1970) reported that the karyotype of R.japonica from Japan was the same as that of Tupistra nutans from Bhutan. But we have not discov ered any chromosome with an intercalary satellite. VIII. Hosta Tratt. (1) H. plantaginea (Lam.) Aschers was shown to have 2n=60. The 60 chromosomes are in 30 pairs,which can be classified into 4 pairs of large chromosomes (7.32- 8.72μm ), 3 pairs of medium-sized ones (4.72-5.60μm), and 23 pairs of small ones (1.40-3.64μm), (Plate 3 ,Table 4 ). The karyotype of H. plantaginea is reported for the first time. (2) H. ventricosa (Salisb.) Stearn was counted to have 2n=120, The 120 chromosomes are in 60 pairs, which can be classified into 8 pairs of large chromosomes (7.00- 8.40μm ), 6 pairs of medium-sized ones(4.40- 6.15um ), 46 pairs of small ones (1.20- 3.85μm), (Plate 3, Table 4). Based on the karyotypes of H. plantaginea and H. ventricosa, the latter is probably a tetraploid in the genus Hosta. Kaneko (1968b) gave a report on the karyotype of H. ventricosa, which is of8 pairs of large chromosomes, 4 pairs of medium-sized and 48 pairs of small ones.     

Cytogenetic characterization of Partamona cupira (Hymenoptera, Apidae) by fluorochromes

Four colonies of the stingless bee Partamona cupira (Hymenoptera: Apidae) were cytogenetically analyzed using conventional staining and the fluorochromes CMA(3) e DAPI. The females have 2n = 34 chromosomes (2K = 32 Mˉ+2 Aˉ). Some females, however, presented an additional large B acrocentric chromosome, to a total of 2n = 35. Chromosome B and the chromosomal pairs 2, 9 and 10 showed CMA (3) (+) bands, indicating an excess of CG base-pairs. A clear association was verified between the P. helleri B chromosome SCAR marker and the presence of a B chromosome in P. cupira. The data obtained suggests that B chromosomes in P. helleri and P. cupira share a common origin.     

Karyological observations on Turbellaria Proseriata: karyometric analysis ofMonocelis fusca,M. lineata (Monocelididae) andParotoplana macrostyla (Otoplanidae)

A karyometric analysis of the chromosome set of the marine turbellariansMonocelis fusca, M. lineata andParotoplana macrostyla has been carried out. The karyotype of the twoMonocelis species investigated (2n=6) is formed by three pairs of small and similarly sized chromosomes: InM. fusca, chromosome 1 is metacentric, chromosome 2 acrocentric and chromosome 3 is subtelocentric.M. lineata also presents one pair of metacentric chromosomes (chromosome 2), while chromosomes 1 and 3 are submetacentric.P. macrostyla (2n=12) reveals two pairs of large metacentric and four pairs of small chromosomes, three of which are metacentric, whereas the last is subtelocentric.     

Comparative cytogenetics in Apareiodon affinis (Pisces, Characiformes) and considerations regarding diversification of the group

Comparative cytogenetic studies in Apareiodon affinis (Pisces, Characiformes) from two hydrographic Brazilian basins showed significant divergences related to the general karyotype structure, C‐banding and nucleolar organizer region (NOR) bearing chromosomes. In the upper Paraná basin population, distinct diploid numbers were observed among sexes, the females showing 2n = 55 and the males 2n = 54 chromosomes, characterizing a multiple sex chromosome system of the ZZ/ZW₁W₂ type. A diploid number equal to 54 chromosomes was found for the Cuiabá river population, without a sex chromosome heteromorphism. However, the occurrence of acrocentric chromosomes represents an unique character for this population. These karyotypic differences indicate that the analyzed populations must represent distinct Apareiodon species. This revised version was published online in July 2006 with corrections to the Cover Date.     

Cytogenetic variability in genus odontocheila (Coleoptera,Cicindelidae): karyotypes,C-banding,NORs and localisation of ribosomal genes of O. confusa and O. nodicornis

Two species of Odontocheila, O. confusa and O. nodicornis, from the Neotropical Region were studied regarding their karyotypes, localisation and activity of ribosomal genes and C-banding. The species, although belonging to the same genus, have quite distinct karyotypes. O. confusa has 10 pairs of autosomes and a single sex chromosome mechanism of the XY/XX type, thus a diploid value of 2n = 22 in males and females. One aneuploid male with a diploid number of 2n = 20 and one male with three B chromosomes were found in a total of eight males studied. O. nodicornis has 17 autosomal pairs and also a single chromosome system but of the X0/XX type, thus a diploid value of 2n = 35 in males and 2n = 36 in females. Fluorescence in situ hybridisation (FISH) revealed the presence of rDNA clusters in two autosomes in both species in mitotic and meiotic figures. Silver staining of male interphase nuclei confirmed the FISH results and showed that all rDNA genes were active. C-banding analysis revealed the presence of constitutive heterochromatin in the centromeres of all chromosomes in the two species plus two pairs in O. nodicornis with terminal positive C-bands. These results are discussed from the cytogenetic and evolutionary point of view.     

A Chromosomal Study on 7 Species of Smilax L.

The chromosome numbers and karyotypes of 7 species of Smilax L. in Liliaceae (s. 1.) are cytotaxonomically studied in this work. Their karyotypic characters, distinction between the species and the chromosomal basis of sexual differentiation are discussed. The karyotypes of most species are first reported. The results are shown as follows (see Tables 1-4 for the chromosome parameters and the karyotype constitution; Fig. 1 for their idiograms): 1. Smilax nipponica Miq. The species is one of the herbaceous species distributed in East Asia. Two karyotypes, 2n = 26(type A) and 2n = 32 (type B), are found in the species (Plate 1: 1-7). The karyotype of No. 88032 (uncertain of -L--M--S- sexuality) is 2n = 26 = 2m + 6st + 6m + 4sm + 6sm + 2st. The karyotype has 4 pairs of L chromosomes, of which the first three pairs are subterminal, and the 4th is median. The karyotype belongs to 3B. No. 88045 (the male) and No. 88046 (the female) have 2n = 32. Their karyotypes are basically uniform, and both are -L--M-- S 2n=32= 2m+4sm+ 2st+ 2m+4sm+ 6m+ 10sm + 2st, also with 4 pairs of L chromosomes, but the 2nd pair is median, and thus different from the type A. The karyotype belongs to 3B. The first pair of chromosomes of the male are distinctly unequal in length, with the D. V. (0.93) of relative length between them obviously greater than that of the female (0.1). The pair seems to be of sex-chromosomes. Sixteen bivalents (n= 16) were observed at PMCs MI of No. 88045 (Plate 1: 4). The major difference between the karyotypes A and B are greater relative length of L chromosomes in the type A than in the type B, and the increase of chromosome number in the karyotype B mainly due to the increase of st chromosomes. Nakajima (1937)reports 2n= 30 for S. hederacea var. nipponica (=S. nipponica, Wang and Tang, 1980). 2. S. riparia A. DC. This species is also herbaceous, distributed in East Asia. Thirty chromosomes were found in root-tip cells (uncertain of sexuality). The kar -L--M--S-yotype is 2n = 30 = 8st + 6sm + 2st + 6m + 6sm + 2st (Plate 3: 1, 5), consisting mainly of sm and st chromosomes. There are 4 pairs of L chromosomes which are all subterminal and the m chromosomes appear to fall all into S category. Though the karyotype belongs to 3B, it is less symmetrical than that of S. nipponica. The species is karyologically rather different from S. nipponica, therefore. The first pair of chromosomes of this material are unequal in length, and it may be a male. The karyotype of this species is first reported. 3. S. sieboldii Miq. The species is a thorny climbing shrub, distributed in East Asia. At PMCs All, 16 chromosomes (n= 16) were found (Plate 2: 6), in accordance with Nakajima's (1933) report for a Japanese material. 4. S. china L. This species, a thorny climbing shrub, is of a wide distribution range mainly in East Asia and Southeast Asia. Two karyotypes were observed in different populations. (1) The population from Xikou has 2n = 96(6x) = 20st+L- -M- 6t + 6sm + 12st + 52(S) (Plate 3:7), of which the first three pairs of chromosomes are terminal, different from those in the other species. The arm ratios of both L and M chromosomes are larger than 2.0, which resembles those of S. davidiana. (2) PMCs MI of the population from Shangyu shew 15 chromosomes (n 15). The hexaploid of the species is recorded for the first time. Hsu (1967,1971) reported 2n = 30 from Taiwai and Nakajima (1937) recorded n = 30 from Japan, which indicates that the karyotype of the species varies not only in ploidy, but also in number. 5. S. davidiana A. DC. The somatic cells were found to have 32 chromosomes, and PMCs MI shew 16 bivalents (Plate 2: 1-5). The karyotype is 2n = 32=-L- -M- -S 8st + 4sm + 4st + 8sm + 8st. The karyotype belongs to 3B, and is less symmetrical than those in herbaceous species. The D. V. (0.20) of relative length between the two homologues of the first pair is slightly larger in the male than in the female (0.14), and it is thus difficult to determine whether they are sexual chromosomes or not. 6. S. glabra Roxb. The species is a non-thorny climbing shrub, distributed in East Asia and Southeast Asia. 32 chromosomes were found in somatic cells. The -L- -M- - Skaryotype is 2n= 32= 8st + 10st+6sm+8st (Plate 3: 2, 6),with only 3 pairs of sm chromosomes (12, 13 and 16th). The karyotype is more asymmetric than that of S. davidiana, although it is also of 3B (Table 1). The karyotype is first reported for the species. 7. S. nervo-marginata Hay. var. liukiuensis (Hay.) Wang et Tang The variety has a relatively narrow distribution range, mainly occurring in eastern China. The chromosomal number of somatic cells is 2n= 32 (Plate 3: 3-4). The karyotype is -L- -M- -S 2n = 32 = 2sm + 6st + 2sm + 2st + 2m + 6sm + 12st, evidently different from that of S. glabra. The first pair of chromosomes are submedian, and much longer than the 2nd to 4th pairs. The ratio in length of the largest chromosome to the smallest one is 4.3. The symmetric degree is of 3C, a unique type. The karyotype of the species is reported for the first time. In Smilax, the known basic numbers are 13, 15, 16 and 17. The two herbaceous species distributed in East Asia have three basic numbers: 13, 15 and 16, while the woody species studied mainly have 16, with no 13 recorded. Mangaly (1968) studied 8 herbaceous species in North America and reported 2n=26 for them except S. pseudo-china with 2n=30. Mangaly considered that a probably ancestral home of Smilax, both the herbaceous and woody, is in Southeast Asia and the eastern Himalayas, and speculated that the ancestral type of Sect. Coprosmanthus is possibly an Asian species, S. riparia. The karyotypes of the two herbaceous species in East Asia consist mostly of sm and m chromosomes, whereas those for the North American species are all of st chromosomes. Based on the general rule of karyotypic evolution, i.e. from symmetry to asymmetry, his speculation seems reasonable. Researches on sex-chromosomes of Smilax have been carried out since 1930 (Lindsay, 1930; Jensen, 1937; Nakajima, 1937; Mangaly, 1968), and they are generally considered to be the largest pair, but there is still no adequate evidence. The result of our observation on S. nipponica may confirm that the first pair of chromosomes of this species is XY type of sex-chromosomes. Chromosomes of the genus are small and medium-sized, varying between 1-6 μm, slightly larger in herbaceous species than in woody ones, larger in the karyotype of 2n=26 than in that of 2n=32. Based on karyotype constitution of the above 5 species, the karyotype in the genus is characterized by 4 pairs of L chromosomes and 2-5 pairs of M chromosomes, and mostly st and sm chromosomes, and by rather asymmetrical 3B type. The degree of symmetry in the above 5 species is from Sect. Coprosmanthus to Sect. Coilanthus, and herbaceous species towoody ones.