Systematics and karyoevolution inMagnoliidae:Tetrameranthus as compared with otherAnnonaceae genera of the same chromosome number

First generic chromosome counts reveal the base number x=7 for the generaTetrameranthus andRollinia. T. umbellatus from the Peruvian Amazon is diploid (2n=14),T. duckei from Brazil (Manaus) is tetraploid (2n=28). In the NeotropicsRollinia (7 species counted) has developed diploid to octoploid taxa (2n=14, 28, 42, 56). Counts of 7 South AmericanAnnona species are presented for comparison (2n=14, 28). The West AfricanCleistopholis patens has 2n=14. The Asian genusMezettia: 2n=14 and the neotropicalGuatteria tribe: 2n=28 are also revised. A detailed karyomorphological comparison, including karyotypes, banding patterns, condensing behaviour of chromosomes and structure of interphase nuclei reveals that the closely related generaAnnona andRollinia are almost identical in their diploid genomes, whereas the polyploid ones differ in their heterochromatin (=hc) composition and number of NO-chromosomes.Cleistopholis, Mezettia and theGuatteria tribe are karyologically and systematically distinct from each other and fromAnnona/Rollinia. Tetrameranthus as compared with the karyomorphology of about 60 other Annonaceous genera has a very peculiar and unusual karyomorphology which underlines its isolated position. Nuclear structures are almost identical in the African genusUvariopsis (2n = 16) and partly similar in theGuatteria tribe; both also share some morphological similarities and possibly are related. From a comparison ofTetrameranthus with several nuclear types within theMagnoliidae, a new model of chromosome evolution in primitive Angiosperms is suggested. In respect to their eco-morphological differentiation the genera investigated differ strongly from each other.Dedicated to Prof. Dr. K.-H.Rechinger on the occasion of His 80th birthday.     

Heterostyly in species ofNarcissus (Amaryllidaceae) andHugonia (Linaceae) and other disputed cases

The hypothesis ofHenriques andFernandes that several Iberian species ofNarcissus (Amaryllidaceae) are tristylous is reconsidered. Contrary to the opinion ofBateman and most subsequent authors, we believe that the available evidence indicates that some populations ofN. triandrus andN. fernandesii, at least, are tristylous; other populations ofN. triandrus are distylous.Hugonia cf.penicillanthemum (Linaceae) from new Caledonia is distylous, but it remains possible that other species ofHugonia are tristylous. The disputed occurrence of heterostyly in S. African species ofBauhinia (Leguminosae),Cleome (Capparaceae) andAneilema (Commelinaceae), and inAgelaea (Connaraceae) is discussed.     

Giemsa karyotypes and their evolutionary significance inScilla bifolia,S. drunensis,andS. vindobonensis (Liliaceae)

Quantitatively evaluated C-banded and conventional karyograms are presented for the related speciesScilla bifolia subsp.danubialis Speta,S. drunensis (Speta)Speta, andS. vindobonensis Speta. On the basis of banding patterns and karyotype structureS. bifolia subsp.danubialis (2n = 18, 2×) andS. drunensis (2n = 36, 4×) are quite similar, whileS. vindobonensis (2n = 18, 2×) is entirely different. There is a moderate degree of karyotypic variation withinS. bifolia subsp.danubialis andS. drunensis. However, inS. vindobonensis karyotypes and banding patterns are almost completely stable over a geographical range of about 500 km. The present results confirm the recent taxonomic separation ofS. vindobonensis fromS. bifolia, and suggest a considerable phylogenetic distance between these two diploid species. The results are discussed with reference to the morphological characters of the species and their geographical distribution.Evolution ofScilla and Related Genera, II.Dedicated to Univ.-Prof. Dr.Elisabeth Tschermak-Woess on the occasion of her 60th birthday.     

Cytogenetical changes of offsprings from the induced tetraploid hybrid betweenRanunculus silerifolius (2n = 16) andR. chinensis (2n = 16) (Ranunculaceae)

Cytogenetical studies were carried out on the successive generations of offsprings from the induced tetraploid hybrid (2n = 32) betweenRanunculus silerifolius (2n = 16) andR. chinensis (2n = 16). Aneuploids, 2n = 30 to 35, frequently occurred. In latter subsequent generations the deviation of aneuploids increased, but the proportion of euploids decreased, accompanied by the reduction of fertility of pollen grains and seed sets. F₂ and F₄ PMCs constantly exhibited meiotic abnormality, i.e. formation of quadrivalents and univalents. The speciation process ofR. cantoniensis (2n = 32), which was presumed to arise from tetraploid hybrids between the above two species, is discussed on the basis of the above evidences.Former contributions of this series areOkada & Tamura (1977) andOkada (1984).     

Cytotaxonomical studies on AsianAnnonaceae

Chromosome numbers of 42 species and 3 varieties from 24 genera of theAnnonaceae have been determined (Table 1); reports for 15 of the genera are new. Among Asian genera 2n = 14 occurs only in the specializedMezzettia, while 2n = 16 is wide-spread and also has been found inAnaxagorea with some primitive characters. 2n = 18 is reported for 11 genera, and tetraploidy (2n = 36) has been observed inPolyalthia. Therefore, an original basic number of x = 8 or x = 9 is suggested at least for the Asian genera of theAnnonaceae.—Cytotaxonomical notes on the critical speciesPolyalthia rumphii andP. affinis are given, and the new combinationNeouvaria parallelivenia (Boerl.)Okada & Ueda is proposed.     

The annual species ofAdonis (Ranunculaceae)—a polyploid complex

The five annual species ofAdonis L., sect.Adonis, growing in Israel, form a series of diploid, tetraploid and hexaploid species. Their somatic chromosome numbers are 2n = 16 inA. annua L.,A. dentata Del. andA. palaestina Boiss., 2n = 32 inA. microcarpa DC., 2n = 48 inA. aestivalis L.; counts forA. dentata, A. palaestina andA. microcarpa are new records. There are indications that alloploidization may have been involved in the process of speciation in sect.Adonis. A taxonomic survey of the 8 species of the section reveals that a higher ploidy level is usually combined with a larger distribution area.     

Experimental evidence on the affinities ofPapaver somniferum (Papaveraceae)

Results obtained from crossing experiments betweenP. somniferum subsp.somniferum (2n = 22) and subsp.setigerum (2n = 44),P. glaucum (2n = 14) andP. gracile (2n = 14) and from the observation of meiotic chromosome pairing in the various hybrids obtained do not provide straightforward evidence for the hypothesis thatP. somniferum originated as a triploid hybrid between taxa similar toP. glaucum andP. gracile (Kadereit 1986a, b).—On the one hand, the pattern of crossability found reflects the closer similarity of subsp.somniferum toP. glaucum and of subsp.setigerum toP. gracile, which was interpreted as segregation of parental characters, and the high frequency of 2n = 28 chromosomes among F₂-progeny from the hybrid subsp.somniferum × subsp.setigerum (2n = 33) might reveal n = 7 as the base number also ofP. somniferum. On the other hand, however, the general difficulty of obtaining hybrids, and the low incidence of bivalent formation in their meiosis, probably indicating a lack of chromosome homology between the different species, do not fit the above hypothesis.—These results are in marked contrast to the morphological similarity between the three species involved.     

Karyotype evolution by centromeric fission inZamia (Cycadales)

The chromosome numbers of several species ofZamia from Mexico are reported.Z. paucijuga, distributed from central Oaxaca to Nayarit, has been found to have 2n = 23, 25, 26, 27 and 28. 2n = 28 is the highest chromosome number yet found in the cycads. Karyotypes of this species differ principally in the number of telocentric and metacentric chromosomes present in each; 2n = 23, 25, 26, 27 and 28 were found to have 5, 3, 2, 1 and 0 metacentric and 8, 12, 14, 16 and 18 telocentric chromosomes, respectively.Z. fischeri has been found to be 2n = 16,Z. furfuracea andZ. loddigesii 2n = 18.Zamia paucijuga on the basis of morphological and ecological characteristics, is considered to be an advanced member of this genus. Chromosome and karyotype evolution inZ. paucijuga may have occurred by centromeric fission of metacentric chromosomes; the karyotypes ofZ. paucijuga are strongly asymmetrical, suggesting that they evolved recently.     

Morphological and cytological investigations ofUlothrix zonata and taxonomy of the related species

The present communication deals with the observations made on the morphology, reproduction and cytology ofUlothrix zonata (Weber & Mohr)Kütz. in culture. The alga displays a remarkable phenotypic plasticity in nature as well as in culture. The present study provides additional evidence of karyology in support ofLokhorst andVroman's treatment ofU. zonata which merges a number of earlier described species in it. The cytological details and chromosome number (n = 10) determined for the Indian isolates ofU. zonata agree with those ofSarma for the British material.NBRI Research Publication No. 63 (N.S.)     

Chromosome analysis ofHaemanthus andScadoxus (Amaryllidaceae)

Chromosome analysis of nine species ofHaemanthus (2n = 16) and four species ofScadoxus (2n = 18), using conventional stains, Quinacrine fluorescence and C-banding, has shown that the two genera do not possess significant amounts of constitutive heterochromatin. The two genera are closely related and differ in respect of a translocation which has resulted in the dysploid reduction in chromosome number from 2n = 18 inScadoxus to 2n = 16 inHaemanthus.     

Chromosome numbers of the European seagrasses

The chromosome numbers of the five European seagrasses have been determined in material from several sites along the coasts of the Atlantic Ocean, the North Sea and the Mediterranean:Zostera marina L., 2n = 12;Z. noltii Hornem., 2n = 12;Posidonia oceanica (L.)Delile, 2n = 20;Cymodocea nodosa (Ucria)Aschers., 2n = 14, 2n = 28;Halophila stipulacea (Forsk.)Aschers., 2n = 18. The difference in chromosome morphology betweenZ. marina andZ. noltii supports the division of the genus into two subgenera.     

Karyosystematics and evolution of AustralianAnnonaceae as compared withEupomatiaceae,Himantandraceae, andAustrobaileyaceae

Chromosome counts are presented for 12 genera and 20 species of AustralianAnnonaceae (all diploid with 2n = 16 or 18; Table 1) and two species ofEupomatiaceae (2n = 20, partly from Papua New Guinea). Detailed studies on interphase nuclear structure, condensing behaviour of chromosomes, and fluorochrome and Giemsa C-banding patterns also includeHimantandraceae (Galbulimima) andAustrobaileyaceae. — Eupomatiaceae completely correspond withAnnonaceae karyologically, their base number 2n = 20 is interpreted to have evolved from 2n = 18 by ascending dysploidy from common ancestors.Eupomatia laurina andE. benettii differ in DNA and constitutive heterochromatin (hc) quantity; their evolution from high to low DNA content probably corresponds to general progressions inMagnoliidae. Austrobaileya has nuclei of the presumably primitive Tetrameranthus type which is closely related to that ofGalbulimima and several other primitive taxa inMagnoliidae. Karyomorphology and other characters support the maintainance of two main branches within theMagnoliidae, Laurales andMagnoliales, withAustrobaileya probably intermediate; theWinteraceae appear more remote.—InAnnonaceae the reestablishment ofAncana is underlined by its chromosome number (2n = 18) the unexpected and specialized disulcate pollen, and various morphological characters which point to a close alliance with the Australian endemic generaFitzalania andHaplostichanthus (also disulcate) and the American genus pairSapranthus/Desmopsis; they are united in the provisionalSapranthus tribe, with a more distant position toFissistigma s. str. (2n = 16). AustralianAnnonaceae exhibit a high generic and a low species diversity; they can be considered as an ± old and partly impoverished outpost of the family with phytogeographical relationships to Asia, Africa and America.—On the base of field observations three main types of floral development inAnnonaceae are proposed, the most elaborated one found in the fly pollinated genusPseuduvaria. The growth form change from shrubs to lianas during the ontogeny ofDesmos andMelodorum, the vegetative propagation of anAncana species and the ecological and evolutionary patterns of the taxa investigated are discussed.     

Cytotaxonomy and breeding system of the genusBiscutella (Cruciferae)

Chromosome counts were determined for 46 populations ofBiscutella representing 28 taxa. The genus was found to contain diploid taxa with 2n = 12, 16 and 18, tetraploid taxa with 2n = 36 and hexaploid taxa having 2n = 54.B. laevigata L. s. l. consists of diploid and tetraploid populations which are poorly differentiated morphologically. TetraploidB. laevigata s. l. and hexaploidB. variegata Boiss. & Reuter (s. l.) are characterized by chromosomal instability. The variation in chromosome numbers and the occurrence of polyploidy is discussed in relation to the taxonomy of the genus. An investigation of the breeding system showed that most of the annual species were self-compatible and partly inbreeding and most of the perennial species self-incompatible and, therefore, outbreeding, while one annual species,B. cichoriifolia Loisel., showed both systems.     

The genusPicris (Asteraceae,Lactuceae) in Tropical Africa

Three species of the genusPicris L. are native in Tropical Africa:P. abyssinica Sch. Bip. (Ethiopia),P. xylopoda Lack, spec. nova (Nigeria, Ethiopia) andP. humilis DC. (Senegal, Mali). There are indications that the two perennial species,P. abyssinica andP. xylopoda, are related to and have evolved from a primitive Central Asiatic stock in a manner parallel to many African species ofCrepis L.P. humilis, on the other hand, is a small annual plant with a high number of derived characters. The introduced species of European origin growing south of the Sahara are briefly mentioned.     

Karyological studies onGentiana sect.Chondrophyllae (Gentianaceae) from China

Nineteen populations of fifteen species ofGentiana sect.Chondrophyllae from China were observed cytologically.Gentiana alsinoides, G. anisostemon, G. asterocalyx, G. exigua, G. heterostemon, G. intricata, G. praticola, G. pseudoaquatica, G. spathulifolia, andG. subintricata all had the same chromosome number of 2n = 20 (or n = 10), whereasG. piasezkii had 2n = 36,G. squarrosa 2n = 38,G. prattii 2n = 18,G. aristata 2n = 14 (n = 7), andG. heleonastes 2n = 12. All these chromosome numbers are documented here for the first time, except forG. squarrosa, where it is a new number report. The basic numbers of x = 6, x = 7 and x = 19 are new for the section. Karyotype analyses of some species revealed that, except for a few cases, the species examined mainly had metacentric chromosomes. 2n = 20 = 2m(SAT) + 18m was found to be the main type of karyotype for the species with 2n = 20. Chromosomal evolution and its mechanism in this section are also discussed.     

Comparative karyomorphology and interrelationships ofSelaginella in Japan

Karyomorphological comparisons were made of 16 native and cultivated species ofSelaginella in Japan. The somatic chromosome numbers are 2n=16 inS. boninensis; 2n=18 inS. doederleinii, S. helvetica, S. limbata, S. lutchuensis, S. nipponica, S. selaginoides, S. tama-montana, andS. uncinata; 2n=20 inS. biformis, S. involvens, S. moellendorffii, S. remotifolia, andS. tamariscina; 2n=30 inS. rossii; and 2n=32 inS. heterostachys. The interphase nuclei of all species examined are uniformly assigned to the simple chromocenter type. The metaphase karyotype of 2n=16 (x=8) is 8 m (=median centromeric chromosomes)+8(st+t)(=subterminal and terminal). The group of the species having 2n=18 (x=9) is heterogeneous karyomorphologically: The karyotype ofS. nipponica is 2n=18=6 m+12(st+t),S. tama-montana 10 m+2 sm(=submedian)+6(st+t), andS. uncinata 6 m+7 sm+5(st+t). Although the remaining five species have the common karyotype 8 m+4 sm+6(st+t), the values of mean chromosome length are variable. Another group of the specles having 2n=20 (x=10) is homogeneous, since all species have the same karyotypes 8 m+4 sm+8(st+t) and have similar chromosome size. The karyotype of 2n=30 is 12 m+6 sm+12(st+t) and is suggested to be a triploid of x=10, and 2n=32=16m+16(st+t), a tetraploid of x=8. Thus, three kinds of basic chromosome numbers, x=8, 9, 10 are present in JapaneseSelaginella examined, and their karyomorphological relationships are discussed.     

Cytology ofCrocus sativus and its allies (Iridaceae)

Populations ofC. cartwrightianus, C. hadriaticus andC. thomasii from the Balkans have 2n = 16 as has the Middle EasternC. pallasii subsp.haussknechtii. C. dispathaceus andC. pallasii subsp.pallasii have 2n = 14 whileC. pallasii subsp.turcicus has 2n = 12.C. niveus has 2n = 28 andC. sativus is an autotriploid with 2n = 24. Karyotype variation was found between populations ofC. pallasii subsp.pallasii in Central Turkey and also inC. pallasii subsp.turcicus.     

Relationships between species ofLeymus,Psathyrostachys, andHordeum (Poaceae,Triticeae) inferred from Southern hybridization of genomic and cloned DNA probes

We have used total genomic DNA as a probe to size-fractionated restriction enzyme digests of genomic DNA from a range ofTriticeae species from the generaLeymus Hochst.,Psathyrostachys Nevski, andHordeum L., and hybrids betweenHordeum andLeymus to investigate their taxonomic relationships. Genomic Southern hybridization was found to be an effective and simple way to assess the distribution and diversity of essentially species-specific and common, repetitive DNA sequences, and is hence especially useful in evolutionary studies. The DNA sequences ofH. vulgare seem to diverge substantially from those ofH. brachyantherum, H. lechleri, H. procerum, andH. depressum. The genome ofThinopyron bessarabicum shows little homology to those of theLeymus species investigated, confirming thatT. bessarabicum is not an ancestral genome inLeymus. Although the genomes ofLeymus andPsathyrostachys share substantial proportions of DNA sequences, they include divergent repeated sequences as well. Hybridization with a ribosomal DNA probe (pTa 71) showed that the coding regions containing structural genes encoding the 18 S, 5.8 S, and 26 S ribosomal RNA were conserved among the species investigated, whereas the intergenic spacer region was more variable, presenting different sizes of restriction fragments and enabling a classification of the species. The rye heterochromatin probe pSc 119.2 hybridized to DNA fromH. lechleri andT. bessarabicum, but not to DNA from the other species investigated.     

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.     

Variation and geographical distribution of ploidy levels inPennisetum sectionBrevivalvula (Poaceae) in Burkina Faso,Benin and southern Niger

Pennisetum sect.Brevivalvula is a species complex characterized by polyploidy and apomixis. Ploidy level was assessed by DAPI-flow cytometry for 304 plants of the section, originating from Burkina Faso, Benin and southern Niger. The results were confirmed for 54 plants based on chromosome counts. The samples show four euploidy levels (with x = 9) distributed among five species:P. hordeoides (2n = 36, 54),P. pedicellatum (2n = 36, 45, 54),P. polystachion (2n = 18, 36, 45, 54),P. setosum (2n = 54), andP. subangustum (2n = 18, 36, 54). The geographical distribution of these ploidy levels seems related to major vegetation zones present in Africa. Diploid populations ofP. polystachion andP. subangustum were found in the Banfora area, in Burkina Faso.