Studies on systematic embryology inScilla (Hyacinthaceae)

Scilla persica and 5 species of the so-calledS. hohenackeri group, namely,S. furseorum, S. puschkinioides, S. vvedenskyi, S. hohenackeri, andS. greilhuberi, have been investigated embryologically with special reference to embryo sac and endosperm development.Polygonum-type embryo sac development was stated inS. puschkinioides andS. greilhuberi. 8-nucleate, normally structured embryo sacs, which could not be specified further due to sparse availability of the material, were stated inS. furseorum, S. vvedenskyi, andS. hohenackeri. InS. persica the embryo sac develops according to the bisporicAllium-type. In most species endosperm development was stated to be nuclear, exceptS. hohenackeri, where the type could not be specified. Other traits of possible taxonomic significance are the number of layers in the outer integument, which is mostly 4, or 5–6 inS. furseorum, and the occurrence of polyploid versus haploid and early degenerating antipodal nuclei, the latter occurring only inS. persica andS. furseorum. These embryological characters may be useful for assessing taxonomic relationship of the present species with other allied groups withinScilla, in particular, theS. siberica alliance,S. messeniaca, and theS. bifolia alliance. TheAllium-type embryo sac, which occurs inS. persica, is also characteristic for theS. siberica alliance, and may be a common derived character. Lack of antipodal polyploidization, as characteristic forS. persica andS. furseorum, occurs also in theS. siberica alliance, and is perhaps another common derived trait indicating phylogenetic relationship. Nuclear endosperm development is more frequent in spring-flowering squills than helobial development, which has previously been stated inS. messeniaca, some species of theS. siberica alliance, and inS. litardierei. While helobial endosperm may be primitive forHyacinthaceae in general, it may, by reversal, also occur as a derived character, at least in some species of theS. siberica alliance.     

Neoschumannia (includingSwynnertonia), a primitive genus of theAsclepiadaceae-Stapelieae

A comparison of the West AfricanNeoschumannia Schltr. and the East AfricanSwynnertonia S. Moore reveals that the two monotypic genera must be united.Swynnertonia is sunk into synonymy ofNeoschumannia and the new combinationNeoschumannia cardinea (S. Moore)Meve is made for the East African species.Neoschumannia is shown to belong to the tribeStapelieae. The taxon exhibits a very unusual character combination: the growth form of a woody liana is combined with a tripartite corona unique within theAsclepiadaceae. The morphology of the corona suggests a position ofNeoschumannia close to the base of theStapelieae —Ceropegiinae alliance.     

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.     

Quantitative analyses of C-banded karyotypes,and systematics in the cultivated species of theScilla siberica group (Liliaceae)

Quantified C-band karyograms are presented for the related speciesScilla siberica, S. mordakiae, S. ingridae, S. amoena, andS. mischtschenkoana. Chromosome structure, banding style, and heterochromatin characters suggest a systematic grouping of two more closely related species pairs:S. siberica andS. mordakiae, S. ingridae andS. amoena; they are part of a larger aggregate, well separated fromS. mischtschenkoana. Four different heterochromatin fractions can be recognized inS. siberica and its relatives, but only two inS. mischtschenkoana. C-bands do not replace, but they are added to euchromatin. The particular origin and history of the cultivatedS. amoena and the triploidS. siberica cv. Spring Beauty appear to be responsible for their karyotype constancy, but chromosome conservatism obviously is genuine inS. mischtschenkoana. The banding data support the systematic grouping proposed on a morphological basis, and provide additional evolutionary evidence.Evolution ofScilla and Related Genera, IV.     

Senecella siberica n. sp. and the position of the genus Senecella in Calanoida classification

Senecella calanoides Juday has been reported from fresh-water lakes of North America, Northern Siberia and inshore brackish waters of Kara and Laptev Seas. Investigation of 11 females and 2 males from the brackish waters of Neelov Bay (Laptev Sea) shows that second species, Senecella siberica sp. n., can be distinguished from S. Calanoides Juday by the greater size, a slightly asymmetrical female genital segment, the 3 external spines on the 3d exopod of 2 to 4th swimming legs and by more longer left endopod digitiform process of the male 5th legs. S. siberica seems to be brackish-water euryhaline species, inhabiting brackish waters with salinity from 1 to 22. The genus belongs to the family Aetideidae and is the only genus with freshwater representatives.     

Mitotic cycle time and DNA content in annual and perennialMicroseridinae (Compositae,Cichoriaceae)

Within eight annual and perennialMicroseridinae species studied, the duration of the mitotic cycle is positively correlated with the nuclear DNA content, cycle time (hrs) = 7.3 + 0.32 × pg DNA/nucleus. Within the generaAgoseris andMicroseris, the annuals have lower DNA contents and more rapid mitotic cycle times than do the perennials. This relationship is predicted by the nucleotypic theory ofBennett. Annual species ofPyrrhopappus have relatively high DNA contents and a proportionately longer mitotic cycle time, but contrary to that expected by the nucleotypic theory as originally proposed have the fastest growth rate and shortest generation time observed in theMicroseridinae. This rapid developmental rate is discussed, nucleotypically, however, by analyzing relationships between DNA content, mitotic cycle time, and cell size.     

Nuclear DNA and heterochromatin contents in theScilla hohenackeri group,S. persica,andPuschkinia scilloides (Liliaceae)

DNA contents (presented as 1C-values) have been determined cytophotometrically in 7 species of theScilla hohenackeri group (10.18 to 22.71 pg), and in the systematically more isolated taxaS. persica (21.02 pg) andPuschkinia scilloides (6.80 pg). The heterochromatin amount is not correlated with the nuclear DNA content. Euchromatin, therefore, is not a particularly conservative part of the genome. However, high C-values and large but few terminal heterochromatin bands, and lower C-values and numerous but smaller heterochromatin bands are found to be linked in theS. hohenackeri group. Obviously, numerous chromosomal changes have accompanied speciation in this group. DNA contents, and C-banded karyotypes are consistent with systematic affinities based on morphological similarities.Evolution ofScilla and Related Genera, III.     

Chemotaxonomy of theSymphytum officinale agg. (Boraginaceae)

In a chemotaxonomic study of the genusSymphytum pyrrolizidine alkaloids and triterpenes were used as chemotaxonomical markers. A micro-extraction methods was developed for screening compounds of very small pieces of herbarium material. The occurrence of the pyrrolizidine alkaloids symphytine and (acetyl-)lycopsamine is very general forSymphytum taxa. Echimidine is present in someS. officinale L. plants and inS. tanaicense Steven. The triterpene isobauerenol is present inS. officinale, S. bohemicum Schmidt,S. tanaicense and inS. officinale var.lanceolatum Weinm. The chemotaxonomic hypothesis, proposed byGadella and collaborators, based on the presence of the triterpene isobauerenol inS. officinale and its absence inS. asperum Lepech. and the presence of the pyrrolizidine alkaloid echimidine inS. asperum and its absence inS. officinale, can no longer be applied absolutely to theS. officinale species complex. The pyrrolizidine alkaloid and triterpene pattern ofS. officinale (2n = 24) andS. bohemicum (2n = 24) is identical.S. bohemicum is morphologically, cytologically and phytochemically very similar toS. officinale. Furthermore, it readily crosses with the white flowered W. European diploids ofS. officinale. Therefore it seems likely that these two taxa are conspecific.S. tanaicense shows a pyrrolizidine alkaloid and triterpene pattern similar toS. officinale (2n = 40). Also on morphological and cytological grounds they are very similar. It seems highly probable thatS. tanaicense is conspecific withS. officinale (2n = 40) and represents an intraspecific variant only.S. officinale var.lanceolatum contained no pyrrolizidine alkaloids but did contain isobauerenol. This feature points to an origin fromS. officinale.     

The phylogenetic relationships ofByblis andRoridula (Byblidaceae-Roridulaceae) inferred from partial 18S ribosomal RNA sequences

The phylogenetic relationships of the angiosperm generaByblis andRoridula have been the subject of ongoing taxonomic controversy. Twenty-eight taxa of varying degrees of alleged relationship, including 3 members of theWinteraceae (as an outgroup), were investigated using partial sequences of 18S rRNA (small subunit) and also compared against the morphological data set fromHufford's (1992) cladistic treatment of 80 members of theRosidae-Asteridae. The morphological analysis placed the two genera in a clade with theSarraceniaceae in theCorniflorae-Asterid group as a sister taxon to anEricales-Hydrangeales clade. The 18S rRNA analysis supports the recently publishedrbcL DNA analysis ofAlbert & al. (1992), withRoridula joined to taxa in the lowerRosidae, butByblis joining instead to members of theAsteridae near theSolanaceae. Comparisons for congruence between the three analyses placeByblis in the higher Asterid group near theSolanaceae, andRoridula possibly nearer theSarraceniaceae andEricales. These results imply that the traditional morphological characters used to relate the two genera are possibly the result of convergence towards similar ecological and life-history strategies rather than synapomorphies.     

Omphalotaceae fam. nov. undPaxillaceae,ein chemotaxonomischer Vergleich zweier Pilzfamilien derBoletales

TheOmphalotaceae fam. nov., which include the generaOmphalotus andLampteromyces, are defined on the basis of characteristic sesquiterpenes and of their ability to cause white-rot. Anatomical and morphological features of the representatives of these genera support the creation of this new family. The occurrence of pigments, typical of theBoletales, and of cyanophilous spores, indicate membership of theOmphalotaceae in the orderBoletales. Relationships to the other families of this order — especially to thePaxillaceae — are discussed. The possible functional significance of fungal metabolites is considered.

Herrn Prof. Dr.J. Poelt zur Vollendung seines 60. Lebensjahres gewidmet.—Veränderte Fassung eines Vortrages auf der Tagung der Deutschen Botanischen Gesellschaft, Wien, September 1984.     

Evolution and systematic relationships in theTriticeae (Poaceae)

The evolution and taxonomic relationships in theTriticeae are discussed with the view to highlight aspects of this agronomically important group of plants, which may be of interest to molecular biology. Some of these aspects are addressed in more detail in adjoining papers in which specific genomic loci have been examined at the DNA sequence or isozyme level. Aspects discussed include the systematics and geographic distribution of theTriticeae species, isozyme and chromosome pairing studies on some of the species as well as more recent developments in DNA analyses. A survey of the systematics of theTriticeae indicated that the genomic system ofLöve is probably the most useful starting point for interpreting molecular data even though the system has many problems from a taxonomic point of view. The geographical distribution ofTriticeae species, using both published and unpublished data, suggested that information of this type taken together with the theory of continental drift provides a broad time-span for considering data from DNA sequence studies. The significance, and modes of analyses, of isozyme studies were assessed because they often provide valuable characters in determining relationships between species. The main character underlyingLöve's andDewey's analyses of theTriticeae, namely chromosome pairing, is discussed with particular reference to isozyme studies to show that in some cases, such as species ofHordeum sensu lato, consistent relationships are obtained. Finally, new developments in understanding chromosome structure are considered in relation to the above variables in the taxonomy and evolution of theTriticeae.     

Phagnalon rechingeri (Inuleae,Asteraceae), a new species from Iran

Phagnalon rechingeri spec. nova from S Baluchestan (Iran) is described as a species new to science and illustrated; its relationships to other species of the genus, in particular to thePh. woodii group from S Arabia, are discussed.Dedicated to Hofrat Univ.-Prof. DrK. H. Rechinger on the occasion of his 80th birthday.     

Vergleichende cytotaxonomische Untersuchungen anRanunculus seguieri und der Artengruppe desR. alpestris (Ranunculaceae)

Morphological and cytological investigations as well as crossing experiments were carried out withRanunculus seguieri Vill. and 4 species of theRanunculus alpestris L. group (R. alpestris L.,R. traunfellneri Hoppe,R. bilobus Bertol.,R. crenatus Waldst. & Kit.). ForR. seguieri andR. alpestris, localities and distribution are given in addition to extensive diagnoses. A key to the species includes morphological characteristics and distribution data forR. traunfellneri, R. bilobus, andR. crenatus. New diagnostic characters are described. Crossing experiments betweenR. seguieri and the species of theR. alpestris group were unsuccessful. All 5 species have a chromosome number of 2n = 16, the record forR. bilobus is new. There is no statistically significant difference between the karyotypes ofR. seguieri andR. alpestris s. str. Nevertheless, according to morphological evidence and crossing experiments,R. seguieri is not closely related to theR. alpestris group.

     

Interspecific hybridizations among species of theElymus semicostatus andElymus tibeticus groups (Poaceae)

Interspecific hybridizations were made between species of theE. semicostatus group, viz.,E. semicostatus (Nees exSteud.)Meld.,E. validus (Meld.)B. Salomon,E. abolinii (Drob.)Tzvel., andE. fedtschenkoi Tzvel., and species of theE. tibeticus group, viz.,E. pendulinus (Nevski)Tzvel.,E. tibeticus (Meld.)Singh,E. shandongensis B. Salomon, andE. gmelinii (Ledeb.)Tzvel., as well as among species within theE. tibeticus group. All species are tetraploid (2n = 4x = 28) and possess SY genomes. Meiotic pairing data from 24 hybrids involving 17 interspecific combinations are presented. The average number of chiasmata per cell ranged from 17.91 to 26.20 in hybrids within theE. tibeticus group, compared with 7.26 to 22.04 in hybrids between the two species groups. Despite the extensive collection of cytological data, there was no definite evidence for confirming or disproving the separate existence of the two groups.     

The 5S DNA units of bread wheat (Triticum aestivum)

A collection of 44 cloned 5S DNA units fromTriticum aestivum cv. Chinese Spring were grouped into 12 sequence-types based on sequence similarity and the respective consensus sequences were then produced. The relationship between these 12 consensus sequences (T. aestivum S 1-S 8 andT. aestivum L 1-L 4), together with two clones sequenced byGerlach andDyer, and the 5S DNA consensus sequences from diploidTriticum spp. were then determined by numerical methods. Both phenetic and cladistic analyses were carried out. The following wheat 5S DNA sequences were found to group with respective sequences from diploidTriticum spp.:T. aestivum S 4, S 6 withT. tauschii S;T. aestivum S 3 withT. monococcum S andT. monococcum S-Rus 7;T. aestivum L 1 andT. aestivum L-G&D withT. speltoides L;T. aestivum L 2, L 3 withT. tauschii L;T. aestivum L 4 withT. monococcum L andT. monococcum L-Rus 12. The analyses suggested that 5 out of the 65S Dna loci present in wheat were identified at the sequence level. The locus that could not be identified in this analysis was the5S Dna-B 1 locus. A group ofT. aestivum sequences (T. aestivum S 1, S 7, S 8, S-G&D) were found to be distinct from the other 5S DNA sequences in the data base. The existence of the distinct group of 5S DNA sequences suggests that there is a gap in our current understanding of wheat evolution with respect to the5S Dna loci.     

Robertsonian differentiation and preferential pairing revealed in species and F1 hybrids of theGibasis linearis group (Commelinaceae)

Three closely related species of theG. linearis group are differentiated by their basic numbers and ploidy levels. The change in basic number involves Robertsonian fusion, but the species also differ by interchange and cryptic structural changes revealed by meiotic pairing in F₁ hybrids.Chromosome Evolution in theGibasis linearis Group (Commelinaceae), II.—Part I:Kenton (1981a).     

The application and citation of the generic nameParmeliopsis (Lecanorales,Parmeliaceae)

The nomenclatural history of the generic nameParmeliopsis is reviewed. Its correct citation is found to beParmeliopsis (Nyl. exStizenb.)Nyl., dating from 1866, not 1869 as commonly cited, withP. placorodia (Ach.)Nyl. as holotype species. There is consequently no nomenclatural problem to the adoption ofForaminella Fricke Meyer, typified byF. ambigua (Wulfen)Fricke Meyer for theParmeliopsis species with falcate conidia. A synopsis of the nomenclature of the North American and European species of both these genera is included.     

Plasmid-mediated nicotine degradation inArthrobacter oxidans

The spontaneous loss byArthrobacter oxidans cells of the nicotine-degrading ability (Nic⁺) was 0.06%. It could be increased by treatment with plasmid-curing agents up to 8%. It was possible by conjugation to restore the Nic⁺ phenotype in such cured derivatives and to transfer the Nic⁺ character to Nic^- Arthrobacter species. Plasmid DNA, 160 kb in size as judged by contour length measurements, could be isolated from cleared lysates ofA. oxidans cells by acridine yellow chromatography. Agarose gel electrophoresis of DNA isolated fromArthrobacter exconjugates revealed the occurrence of plasmid DNA within these strains; its mobility was similar to that of the plasmid DNA present inA. oxidans. Although the expression and inducibility of the transferred genes was poor in most of theArthrobacter species exconjugants, apparently authentic 6-hydroxy-l-nicotine oxidase could be identified in these cells after enrichment by an enzyme-specific chromatography.Abbreviations 6-HDNO 6-hydroxy-d-nicotine oxidase - 6-HLNO 6-hydroxy-l-nicotine oxidase - kb kilobase - Nic⁺ ability to usel- ord-nicotine as sole carbon and nitrogen source - Nic^- absence of Nic⁺ character Enzymes (EC 1.5.3.5.) 6-Hydroxy-l-nicotine oxidase, 6-hydroxy-l-nicotine: oxygen oxidoreductase - (EC 1.5.3.6.) 6-hydroxy-d-nicotine oxidase, 6-hydroxy-d-nicotine: oxygen oxidoreductase - (EC 3.1.4.22) ribonuclease A, ribonucleate 3-pyrimidino-oligo-nucleotidohydrolase     

The genusAntennaria (Asteraceae: Inuleae) in western North America: Morphometric analysis ofAntennaria alborosea,A. corymbosa,A. marginata,A. microphylla,A. parvifolia,A. rosea,andA. umbrinella

Multivariate analysis of vegetative and reproductive characters was used to examine morphological relatedness amongAntennaria alborosea A. E. Porsild,A. corymbosa E. Nels.,A. marginata Greene,A. microphylla Rydb.,A. parvifolia Nutt.,A. rosea Greene, andA. umbrinella Rydb. Both pistillate and staminate plants were examined. Some of the characters examined were variable in one species, but stable in another (i.e., presence or absence of papillae on the achenes). Our analyses indicate that the seven species are morphologically distinct. It is hypothesized that theA. rosea agamic complex arose through hybridization amongA. corymbosa, A. microphylla, A. umbrinella, and possiblyA. dioica (L.)Gaertn. However, hybridization between the three former species and others, as well as their subsequent morphological responses to different environmental conditions causes confusion in recognizing the taxa.Antennaria angustifolia Rydb.,A. arida E. Nels.,A. confinis Greene,A. scariosa E. Nels.,A. foliacea humilis Rydb.,A. concinna E. Nels., andA. viscidula E. Nels. are considered to represent F 1 hybrids.     

The genusIschnea (Asteraceae,Senecioneae) in New Guinea

The endemic New Guinean genusIschnea F. Muell. (Asteraceae, Senecioneae, Blennospermatinae) is revised and four species are recognized. Characters of special interest are tubeless ray florets, male disc florets, and secretory spaces in leaves. A principal component analysis is made on theIschnea elachoglossa F. Muell. complex which shows great variation. One new species,I. capellana Swenson, from the Star Mountains, is described. A key, illustrations, and distribution maps to all species are supplied.