Considerations on the neoblasts of planarians on the basis of certain karyological evidence

The problem of the sexual differentiation of the neoblasts of planarians is approached on the basis of karyological evidence assembled by the author and by his collaborators. In the polyploid and pseudogamic biotypes of Dugesia benazzii, D. lugubris and Polycelis nigra, the transformation of the neoblasts into oogonia or spermatogonia is accompanied by variations in the chromosome set. These variations may be considered to be dependent upon the gradient of sexuality — that is, of the territorial influences that determine the evolution in a female or a male direction. Significant evidence is also inferred from the chromosome cycle of hybrids between amphigonic diploid biotypes and polyploid biotypes. A new direction of research, based on the comparison between anterior and posterior regenerated segments of experimental polyploids with variable chromosome sets aims at establishing possible regional differences in the set of the neoblasts.Dedicated to Prof. Dr. J. Seiler on the occasion of his eightieth birthday.     

Taxonomy of the genusBrimeura (Hyacinthaceae)

A taxonomic reevaluation of two little-knownBrimeura taxa,B. fontqueri (Pau)Speta andB. duvigneaudii (L. Llorens)Rosselló et al., has been made.Brimeura fontqueri, described from the Iberian peninsula, has been put into synonymy ofB. amethystina (L.)Salisb., since it could not be distinguished on morphological, anatomical or cytogenetic grounds.Brimeura duvigneaudii, from the Balearic Islands, is closely related toB. amethystina and has 2n=28 chromosomes. It differs from the latter by its naked bulbs lacking dark cataphylls, and its narrower leaves and whitish corollas. Accessory chromosomes are reported for the first time in the genus. Karyological instability (with chromosome numbers ranging from 2n=28 to 42) is reported for a population ofB. fastigiata (Viv.)Chouard. A key to the recognized taxa ofBrimeura is provided.     

Chromosome numbers of some species of the genus<Emphasis Type="Italic">Hieracium</Emphasis> s.str. (<Emphasis Type="Italic">Asteraceae</Emphasis>) from Turkey

Results of a karyological analysis of eight species collected from northeast Anatolia, Turkey are presented. The following chromosome numbers were determined:H. medianiforme (Litv. etZahn)Juxip 2n=36,H. karagollense (Zahn)P.D. Sell etC. West 2n=36,H. argillaceoides (Litv. etZahn)Juxip 2n=36,H. amblylepis Boiss. 2n=27,H. lanceolatum Vill. 2n=27,H. asterodermum (Woronow etZahn)Juxip 2n=27,H. umbellatum L. 2n=18,H. laevigatum Willd. 2n=27. The chromosome numbers of five of these seven species are presented for the first time. The results show a high proportion of triploids and tetraploids within the taxa studied.     

Chromosome numbers in selected species ofHieracium sect.Alpina (Asteraceae) from Central and eastern Europe

Chromosome numbers are reported for 15 taxa ofHieracium sect.Alpina (Griseb.)Gremli from Central and eastern Europe (Austria, the Czech Republic, Poland, Romania, Slovakia, Ukraine). The mode of reproduction was also studied for some of the taxa. For the first time the chromosome counts of 5 taxa from theHieracium rohacsense group are given:H. rohacsense Kit. (the West Carpathians),H. ratezaticum (Nyár. etZahn)Mráz (the South Carpathians) and a still unnamed taxon of theH. rohacsense group from Mt. Pop Ivan (the East Carpathians) are tetraploid (2n=36);H. rauzense Murr (the Eastern Alps) andH. borsanum Mráz (the East Carpathians) are triploid (2n=27).H. krivanense (Woł. etZahn)Schljakov (the West Carpathians) is tetraploid,H. brevipiliferum Mráz (the South Carpathians) is triploid; these are the first karyological reports of both taxa belonging to theH. fritzei group. The tetraploid chromosome number was revealed for the first time in an unnamed taxon of theH. nigrescens group from the West Carpathians, and inH. nigrescens subsp.koprovanum Rech. f. etZahn. InH. alpinum L. s.str. triploid (2n=27) populations from the West Carpathians and diploid populations (2n=18) from the East Carpathians were confirmed. ForH. halleri Vill. (theH. alpinum group, the West Carpathians) andH. nigrescens Willd. (the West Sudeten), the numbers 2n=27 and 2n=36, respectively were found, which is in accordance with previous data. The triploid level (2n=27) forH. pinetophilum (theH. fritzei group) and the tetraploid level (2n=36) forH. stygium Uechtr. (theH. chlorocephalum group) both from the West Carpathians were confirmed. One new species, onenomen novum and one new combination at the level of species are published in this paper.     

Karyosystematic studies on threeCrepis species (Asteraceae) endemic to Greece

This work examines the cytogeographical distribution, the morphological characters, and the karyotypes of threeCrepis species endemic to Greece (C. sibthorpiana, C. incana, andC. heldreichiana). C. sibthorpiana is diploid (2n = 2x = 8),C. incana is diploid (2n = 2x = 8) and tetraploid (2n = 4x = 16, 17), andC. heldreichiana is always dekaploid (2n = 10x = 40). The Giemsa positive bands, usually pairs of dots, are mainly centromeric inC. incana, while they are terminal inC. sibthorpiana (on the short arm of all chromosomes) and inC. heldreichiana (on both arms of all chromosomes). Intercalary C-bands are scarce and usually variable within karyotypes, individuals, and species. The most variable karyotype both in Feulgen and Giemsa preparations is that ofC. incana, in which also supernumerary chromosomes were observed, which are polysomic to standard set members. On the basis of morphological and karyological data the evolutionary relationships among the threeCrepis taxa are discussed.     

Karyotypes of the Echinogammarus berilloni-group (Crustacea,Amphipoda) from Spain

The chromosome number and karyological features of Iberian populations of seven species of the Echinogammarus berilloni-group (Crustacea, Amphipoda) have been studied. For comparison, Gammarus gauthieri, belonging to the G. pulex-group was also studied. Four species of the berilloni-group share the same number n=27. Other numbers found were n=25, n=26 and n=28. The chromosomes of these species have a centromeric region surrounded by large heterochromatic blocks at late prophase. There-after, the centromere splits precociously. C. gauthieri has n=26, the same number found in the pulex-group. This species has larger chromosomes than the former but it does not show these karyological peculiarities.Cytological observations confirm both the close relationship among species of the berilloni-group and the differentiation with respect to the pulex-group. On the other hand, the existence of different numbers confirms other results that reject the older idea that speciation within Gammaridea occurred with minor changes in karyotypic characters.     

Chromosomes of Syrphidae

In this report the karyotypes of 54 species of the tribe Milesiini and of four species of the tribe Myoleptini are described in detail with illustrations and idiograms. These species belong in the genera Lejota, Myolepta, Blera, Calliprobola, Criorhina, Hadromyia, Milesia, Somula, Sphecomyia, Spilomyia, Syritta, Temnostoma, Tropidia and Xylota. Six species have 2n = 8 chromosomes, 35 have 2n = 10 (including Xylota nemorum which has about 20 extra microchromosomes in some specimens), 15 have 2n = 12, one has 2n = 14, and Somula decora has 2n = 10 large chromosomes plus about eight microchromosomes. The mean total complement length (TCL) for 347 complements analysed in these tribes was 53.7 but there is great variation between TCL's of complements analysed even from a single fly. Karyotypes of species of Myolepta in the Myoleptini resemble in certain respects those of species of Tropidia in the Milesiini. Our observations support Currran's transfer of Lejota cyanea to the Milesiini. The 2n = 12 karyotypes of species of Blera, Criorhina, Lejota, Milesia, and to a lesser extent Sphecomyia, have some features in common. Spilomyia species have rather distinct 2n = 10 karyotypes. Certain species in Calliprobola, Syritta and Hadromyia are karyologically similar to some species of the genus Xylota in which species studied fall into fairly distinct karyological groups. These observations provide clear evidence of the accumulation of karyotypic variations in the origin of species in these two tribes.     

Karyotype studies in seven species of cyprinidae

The present report embodies karyotype studies of seven Indian cyprinids. Of these, the karyotypes of five species possess chromosomes all of which are acrocentric. These areLabeo calbasu (Ham.) 2n=54,Puntius sophore (Ham.),P. conchonius Ham.,P. stigma (Ham.) 2n=50 andChela bacaila (Ham.) 2n=52. The karyotype ofCrossocheilus latius punjabensis Mukerji has 48 chromosomes, 12 of which are metacentric (2n=12m+36r's). InAmblypharyngodon mola (Ham.), 52 chromosomes form the diploid set which include 8 metacentrics. In none of the seven species morphologically distinguishable sex chromosomes were found.Literature on cyprinid karyotypes has been reviewed in order to understand in how far the cytological characters are in agreement with the classification based on morphological studies. The validity ofMatthey's notion of nombre fondamental to establish kinship between cytologically known cyprinid species has also been discussed.     

月季种质资源的倍性变异及核型多样性研究(英文)

采用常规压片法对包括5个蔷薇野生种、8个古老月季及9个现代月季品种共22份月季种质资源进行核型分析。供试材料共有3种不同倍性:5个野生种中粉团蔷薇为三倍体(2n=3x=21),其他4个材料为二倍体(2n=2x=14);9个现代月季品种均为四倍体(2n=4x=28);而古老月季品种中包含二、三、四倍体3种倍性。22份材料中共发现4种不同类型的核型,在野生种中为1A、2A;古老月季中为1A、2A、1B;现代月季中为1A、1B、2B。另外,供试材料在核不对称系数、着丝粒指数、随体数目及位置、染色体相对长度组成等方面差异较大,说明在月季种质资源中存在着丰富的核型多样性。     

Karyological and gonadal sex of eels(Anguilla anguilla) from the German Bight and the lower River Elbe

Yellow eels(Anguilla anguilla) taken during summer from random commercial trapnet samples in the littoral area of Helgoland (n=116) and from a freshwater area of the River Elbe near Hamburg (n=109) were examined with regard to their karyological (i.e. existence of female sex chromosomes) and gonadal sex. In 47 % and 21 % of the two samples, respectively, chromosomes were unidentifiable because of insufficient numbers of mitotic plates. All eels from Helgoland, except one phenotypically undetermined fish, exhibited female gonads: 48 had female sex chromosomes and 13 were karyologically males. As found previously in the River Elbe, eels with male gonads predominated (n=55); 25 were undifferentiated. Of the gonadal males 26 were karyological males and 16 karyological females; the rest could not be identified by chromosome patterns. In contrast, all but one of the Elbe eels with female gonads (n=28) had female sex chromosomes. Some aspects of the sex reversal documented in the eel are considered.     

G-band homology and C-band variation in the Japanese mustelids,Mustela erminea nippon andM. sibirica itatsi

The diploid number(2n)and fundamental number (FN) were 44 and 64 inMustela erminea nippon and 38 and 64 inM. sibirica itatsi. In spite of such a marked dissimilarity in their chromosome constitution, most of the chromosomes of these two species showed high G-band homology. On the other hand, interspecific variations in the amount of C-heterochromatin were observed in several pairs of chromosomes which were regarded, based on their G-banding patterns, to have arisen from a common origin. Some of the chromosome pairs associated with the C-heterochromatin variations showed significant differences in length or arm ratio, whereas others did not. These findings strongly indicate that the G-banding patterns might have been well conserved, at least in the euchromatic regions, through the speciation process; in contrast, C-heterochromatin showed quantitative variations, some of which could be regarded to have been formed by duplication. Thus, the karyological relationships between the Japanese ermine and the Japanese weasel could be explained by Robertsonian fusion and quantitative alteration of C-heterochromatin.     

Supernumerary chromosomes in the karyotype of the Siberian spruce, P. obovata

Results of karyological study of ornamental forms of Picea obovata Ledeb. are presented. Typical chromosome number (2n) is 24, but some trees have one or two additional chromosomes (2n = 24 + 1B; 2n = 24 + 2B). Heritability of additional chromosomes, pollen fertility, morphological features of cones, and seed quality in trees with and without additional chromosomes were studied. System of B-chromosomes is of importance for population and species adaptation and possibly plays a role in adaptation of P. obovata under introduction.     

Zur Cytotaxonomie vonArabis hirsuta agg. (Cruciferae). IV. Chromosomenzahlen vonA. sagittata (Bertol.) DC. undA. hirsuta (L.)Scop. s. str. aus Europa

Zusammenfassung A. sagittata (Bertol.) DC. von zehn Herkünften aus Europa ist mit 2 n=16 diploid.A. hirsuta (L.)Scop. s. str. einschließlich der sicherlich hierhergehörigen var.glaberrima Wahlenb. von 30 europäischen Herkünften ist mit 2 n=32 tetraploid; diploide Pflanzen konnten beiA. hirsuta s. str. nicht gefunden werden.

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Summary A. sagittata (Bertol.) DC. from 10 different places in Europe has 2 n=16 chromosomes and is diploid.A. hirsuta (L.)Scop. s. str., its var.glaberrima Wahlenb. being included, has been investigated from 30 provenances in Europe, it has the tetraploid chromosome number 2 n=32, diploid plants could not be found in this species.A. hirsuta var.glaberrima (2 n=32) is surely belonging toA. hirsuta s. str. and not toA. allionii (2 n=16).

     

Ribosomal RNA genes in biotypes ofScilla peruviana (Liliaceae)

Scilla peruviana biotypes have different chromosome numbers due to changes in the nucleolar chromosomes and polyploidy. We have examined two diploid (2n = 15 and 2n = 16) and two tetraploid biotypes (2n = 28 and 2n = 32). From the results of rRNA/DNA filter hybridizations it appears that rDNA percentages of the diploid biotypes are, approximately, 2.2-fold higher than those of the tetraploid biotypes. To examine the rRNA gene structure we have utilizedSouthern blot hybridization after DNA digestions with three restriction enzymes: Eco RI, Hind III and Bam HI. From the band analysis of both single and double digestions it has been possible to reveal the presence, in the diploid biotypes, of three gene types, heterogeneous both for length and for nucleotide sequences in the external spacer. The three rRNA genes are 12 600, 12 700, and 12 800 base pairs long and they have a different position of the Hind III sites in the external spacer. On the other hand, a single gene type of 12 600 base pairs, identical to the first type of the diploid biotypes, surprisingly exists in the tetraploid biotypes. Considerations on the rRNA gene regulation and evolution are made.     

Karyology and systematics of the genusAmbavia and otherAnnonaceae from Madagascar

New chromosome counts and nuclei structures are reported forAnnonaceae species from Madagascar:Ambavia (2n = 14),Xylopia (2n = 16) andPolyalthia (2n = 18). This first generic count ofAmbavia and its nucleotypic parameters underline its long term isolation from the African continent and it should be regarded as an extremely distinct member of the basic stock of AfricanAnnonaceae. Some karyological similarities are found with the African generaCleistopholis (2n = 14) andUvariopsis (2n = 16) and the AmericanTetrameranthus (2n = 14, 28). The karyology ofXylopia is completely in line with previous results from the Palaeo- and Neotropics.Polyalthia has 2n = 18, and x = 9, probably the only base number within the whole genus. Fluorochrome and Giemsa-C-band patterns are identical with different congeneric species.Dedicated to Prof. DrElisabeth Tschermak-Woess on the occasion of her 70th birthday.     

Bemerkungen zur Karyologie und Systematik einiger Sippen der Gattung Vicia L

Continuing the earlier investigations of Vicia species, karyologically not examined hithero, the following taxa of th genus have been described:

• 1 Chromosome numbers reported for the first time–V. Meyeri Boiss. (2n = 14), V. pubescens (DC.) Link (2n = 14), V. graminea SM (2n = 14), V. ramuliflora (MAXIM .) OHWI (2n = 28), V. semiglabra RUPR . ex BOISS . ssp. caucasica (EKVTIM .) RADZHI (2n = 10), V. semenovii (RGL . et HERD .) FEDTSCH . (2n = 12), V. costata LDB (2n = 12), V. hajastana GROSSH . (2n = 10).
• 2 Re-investigations – V. tenuissima (M. BIEB .) SCHINZ et THELL . (2n = 14), V. benghalensis L. (2n = 14), V. lathyroides L. (2n = 12).

Brief cytological and systematical remarks are given for all the species mentioned above. Discrepancies in the literature are especially discussed (V. benghalensis, V. peregrina, V. lathyroides). Our data support the uniformity of the subgen. Ervum in regard to chromosome number (2n = 14) and primitivity of the karyotype. The finding of an advanced karyotype with 10 chromosomes (V. semiglabra) within the subgen. Cracca has been recorded for the first time. In this group a new polyploid taxon (V. ramuliflora) has been found too. The known polyploid representatives of the genus are summarized, all of which belong to perennial species of the subgen. Cracca. Most of the taxa are characterized by obviously distinct karyotypes, that is partly ture for chromosome sizes too (conspicuously long: V. hajastana, V peregrina; conspicuously shrt: V. ramuliflora, V. lathyrodies). This striking karyological differentiation seems to refer not only to the Old world species but also to the New world ones, of which V. graminea (and a strain named „V. selloi”︁) has been examined for the first time. In general the chromosome number and structure (besides the traditional morphological characters) have been proved as extremely valuable for taxonomical considerations within the genus. This is a common situation in many other plant groups too. We therefore think of further cytotaxonomical studies as especially suitable for explaning the evolution and the evolutionary mechanisms within the genus.     

Trisomy associated with loss of maturation capacity in a long-term embryogenic culture of Abies alba

 Karyological studies were made on a 6-year-old embryogenic cell line of Abies alba. Embryogenic cells were obtained from a mature zygotic embryo cultivated on modified MCM-medium and subcultured every 3 weeks. Three years after induction, part of the cell line was transferred to media supplemented with 500 or 1000 mg l^-1 caseine hydrolysate and 500 mg l^-1 L-glutamine. Approximately 3 years after addition of the organic nitrogen to the medium, morphological changes such as malformation of the suspensor cells and a loss of maturation capacity occurred. Chromosome counts revealed that all cells cultivated on medium with organic nitrogen were trisomic. Fluorescent-banding methods and comparison with an euploid cell line showed that the additional chromosome belonged to the group of long, metacentric chromosomes of Abies alba without secondary constriction. Those cells cultured on medium not supplemented with caseine hydrolysate and L-glutamine retained a stable chromosome number of 2n=24. Both normal and deformed suspensor cells were observed. The maturation frequency was very low. The emergence of aneuploidy within one cell line could be the consequence of high selection pressure caused by the different culture conditions. Received: 27 February 1997 / Accepted: 7 March 1997     

Karyotypic studies in Solanum section Lasiocarpa (Solanaceae)

Mitotic chromosomes of 13 species included in Solanum sect. Lasiocarpa were studied. All species have 2n = 24. The chromosome numbers of S. stagnale, S. felinum, and S. repandum are reported for the first time. Statistical analyses of chromosomes, genome length, and centromere position yielded estimates of karyotype composition and asymmetry. A generalized karyotype of the section shows that most of the chromosomes are metacentric (73%) or submetacentric (25.6%). Two pairs of subtelocentric chromosomes are present only in S. sessiliflorum. Satellites are quite common, characterizing chromosomes for ten species and are attached to the short arms of either m or sm chromosomes. They could be seen in 10% to 70% of the cells. Only S. pseudolulo bears two satellited chromosomes, one of them attached to a long chromosome arm. Although the section is chromosomally quite homogeneous, species can be distinguished by karyotype formula, presence of satellites in a particular chromosome pair, and total chromosome length. There are no indications of major chromosomal rearrangements within the section. Using cytological data exclusively, cluster analysis indicates S. sessiliflorum is isolated in the section. Solanum candidum and S. vestissimum are somewhat isolated as well and have unique karyological traits. Solanum pectinatum has a peculiar karyotype, but in the phenogram it is not particularly separated. Karyotype features suggest that morphological differentiation was not always followed by chromosomal divergence. The origin of the domesticated S. quitoense is no further elucidated by our data.     

Genomic characterisation and the detection of raspberry chromatin in polyploid Rubus

 This paper reports genomic in situ hybridization (GISH) and fluorescent in situ hybridization (FISH) data for chromosomes of raspberry (Rubus idaeus 2n=2x=14), blackberry (Rubus aggregate, subgenus Eubatus. 2n=2–12x=14–84) and their allopolyploid derivatives used in fruit breeding programmes. GISH was used to discriminate labelled chromosomes of raspberry origin from those of blackberry origin in allopolyploid hybrid plants. The raspberry chromosomes were labelled by GISH at their centromeres, and 1 chromosome was also labelled over the short arm. In one allopentaploid plant a chromosome carried a terminal signal. Karyotype analysis indicated that this is a blackberry chromosome carrying a raspberry translocation. GISH analysis of an aneuoctaploid blackberry cv ‘Aurora’ (2n=8x=58) showed that both whole and translocated raspberry chromosomes were present. The basic Rubus genome has one ribosomal DNA (rDNA) locus, and in all but one case all levels of ploidy had the expected multiples of rDNA loci. Interestingly, in the blackberry cv ‘Aurora’, there were only six sites, two less than might be predicted from its aneuoctaploid chromosome number. Our results highlight the potential of GISH and FISH for genomic designation, physical mapping and introgression studies in Rosaceous fruit crops. Received: 20 February 1998 / Accepted: 12 May 1998     

A karyological study of the genus Pnigalio Schrank (Hymenoptera: Eulophidae): assessing the taxonomic utility of chromosomes at the species level

We provide a karyological study of 12 species of the genus Pnigalio in an attempt to evaluate the taxonomic utility of karyotypes at the species level. For all species of Pnigalio examined the number of chromosome was 2n=12. Karyotype formulae presented mainly metacentric and submetacentric chromosomes, although a pair of acrocentrics or subtelocentrics, shorter than biarmed chromosomes, was present in some species. The analysis of karyotypes of Pnigalio showed frequent but not general interspecific variability of the chromosome traits. Although most of the studied species revealed concordance between morphological and karyological characters (centromeric index and relative length), two other categories have been identified: morphologically distinct species without reciprocal differences in karyotype structure, and morphologically similar species that strongly differ in chromosomal characters.