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  • Column liquid chromatography  (88)
  • Angiosperms  (77)
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  • Springer  (165)
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  • 1
    ISSN: 1432-1432
    Schlagwort(e): Chloroplast 4.5S rRNA ; Cytosolic and chloroplast 5S rRNAs ; 5.8S rRNA ; 18S rRNA ; Nucleotide sequences ; Phylogenetic trees ; Angiosperms ; Gymnosperms ; Monocotyledons ; Dicotyledons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Complete or partial nucleotide sequences of five different rRNA species, coded by nuclear (18S, 5.8S, and 5S) or chloroplast genomes (5S, 4.5S) from a number of seed plants were determined. Based on the sequence data, the phylogenetic dendrograms were built by two methods, maximum parsimony and compatibility. The topologies of the trees for different rRNA species are not fully congruent, but they share some common features. It may be concluded that both gymnosperms and angiosperms are monophyletic groups. The data obtained suggest that the divergence of all the main groups of extant gymnosperms occurred after the branching off of the angiosperm lineage. As the time of divergence of at least some of these gymnosperm taxa is traceable back to the early Carboniferous, it may be concluded that the genealogical splitting of gymnosperm and angiosperm lineages occurred before this event, at least 360 million years ago, i.e., much earlier than the first angiosperm fossils were dated. Ancestral forms of angiosperms ought to be searched for among Progymnospermopsida. Genealogical relationships among gymnosperm taxa cannot be deduced unambiguously on the basis of rRNA data. The only inference may be that the taxon Gnetopsida is an artificial one, andGnetum andEphedra belong to quite different lineages of gymnosperms. As to the phylogenetic position of the two Angiospermae classes, extant monocotyledons seem to be a paraphyletic group located near the root of the angiosperm branch; it emerged at the earliest stages of angiosperm evolution. We may conclude that either monocotyledonous characters arose independently more than once in different groups of ancient Magnoliales or that monocotyledonous forms rather than dicotyledonous Magnoliales were the earliest angiosperms. Judging by the rRNA trees, Magnoliales are the most ancient group among dicotyledons. The most ancient lineage among monocotyledons leads to modern Liliaceae.
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 178 (1991), S. 195-223 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Podostemaceae ; Tristichoideae ; Indotristicha ramosissima ; Rheophytes ; water plants ; life history ; development ; root-shoot model ; leaf-stem intermediates ; phyllotaxis ; flower structure ; systematics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The developmental morphology ofIndotristicha ramosissima, a submerged rheophyte from South India, is described. Besides creeping organs (called roots) there are branched shoots with two kinds of short-lived photosynthetic appendages: scales and compound structures (called ramuli). These ramuli may be interpreted as leaf-stem intermediates because they combine typical leaf characters (extra-axillary position, determinate growth, subtending an axillary bud) and typical stem characters (nearly radial symmetry, acropetal development with apical meristem, arrangement of the scaly subunits helical or irregular). Floral shoots arise from axillary exogenous buds along the vegetative shoots, occasionally also from endogenous buds along the roots and vegetative shoots. The uppermost scales and ramuli of each floral shoot form a cup-like structure around the base of the terminal flower.Indotristicha is thought to be primitive within theTristichoideae (Podostemaceae). Some morphogenetic switches are postulated in order to deriveIndotristicha from a putative ancestor that still showed the classical root-shoot model typical of most angiosperms.
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 178 (1991), S. 225-233 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Gramineae ; Eleusine ; DNA amount ; intra- and interspecific variation ; karyotypes ; hybridisation ; polyploidy ; domestication ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract 2C nuclear DNA amounts were determined in 30 collections belonging to 10 species ofEleusine. About a 2.5-fold variation in genome size is evident in the genus. The 2C DNA amount in the diploid species ranged from 2.50 pg inE. verticillata to 3.35 pg inE. intermedia. In contrast, the tetraploid species showed a range from 4.95 pg inE. africana to 6.13 pg inE. floccifolia. At intraspecific level 10 collections ofE. coracana, 6 ofE. indica, 4 ofE. africana, 2 ofE. tristachya, and 2 ofE. kigeziensis did not show any significant variation. However, 2 collections ofE. floccifolia, connected with polyploidy, displayed about 90% variation. Polyploid species showed approximately double the genome size of that of their corresponding diploids. An evolutionary increase in DNA amount is evident inE. coracana during the course of its origin and domestication fromE. africana.
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 178 (1991), S. 235-245 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Orchidaceae ; Ophrys ; Orchis ; Anacamptis ; Polyploidy ; aneuploidy ; karyology ; systematics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Studies on chromosome numbers and karyotypes in Orchid taxa from Apulia (Italy) revealed triploid complements inOphrys tenthredinifera andOrchis italica. InO. tenthredinifera there is no significant difference between the diploid and the triploid karyotypes. The tetraploid cytotype ofAnacamptis pyramidalis forms 36 bivalents during metaphase I in embryo sac mother cells. Aneuploidy was noticed inOphrys bertolonii ×O. tarentina with chromosome numbers n = 19 and 2n = 38. There were diploid (2n = 2x = 36), tetraploid (2n = 4x = 72), hexaploid (2n = 6x = 108) and octoploid (2n = 8x = 144) cells in the ovary wall of the diploid hybridOphrys apulica ×O. bombyliflora. Evolutionary trends inOphrys andOrchis chromosomes are discussed.
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 178 (1991), S. 153-178 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Scrophulariaceae ; Angelonia ; Anthophoridae ; Centris ; Oil flowers ; pollination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The manner whereby the oil-producing bisaccate flowers ofAngelonia (Scrophulariaceae) are pollinated by female oil-collecting bees is reported for the first time. Observations were made in the Caatinga formation of Pernambuco, NE. Brazil, on four synchronopatric species. These differ in sizes and structural details of the corolla, level of flower exposition, and habitat preferences. All legitimate visitors wereCentris spp. (Anthophoridae):Angelonia hirta was mainly pollinated byC. fuscata andA. pubescens byC. hyptidis; A. bisaccata andA. hookeriana shared an unidentified species. Several exomalopsine, tetrapediine and meliponid bees exploit the flowers less descriminately for oil or pollen, respectively, without regularly contacting anthers and stigma. The flowers are protandrous, and are self-incompatible except those of the annualA. pubescens. After alighting, theCentris bees introduce their front legs simultaneously into each of the pouches and start alternate collecting movements to gather the oil from the trichome elaiophores. While doing so, they are forced by projections of the corolla floor to press their head under the anthers and stigma, whereby pollen is transferred with their frons or clypeus. On account of their collector type and behaviour,C. fuscata andC. spec. are not specialized toAngelonia but may equally exploit other nonrelated taxa for oil, whereasC. hyptidis exhibits oligolecty onA. pubescens. It possesses relatively elongate forelegs with padlike collectors suitable for sweeping the lipids from the scattered glandular hairs inside the divergent spurs of its host. It is the only species that also collects pollen (by buzzing) from the oil host.A. hirta and relatives, provided with dense elaiophore carpets, are, for their part, adapted to “scraping”Centris species with typical oil collectors. Flower and bee phenologies, although largely dependent on the irregular rainfalls, are not always coincident.
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 178 (1991), S. 179-194 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Clusiaceae ; Harungana madagascariensis ; Androecium ; stamenpetal complex ; floral nectaries ; floral development ; floral anatomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The mature flower ofHarungana madagascariensis (Choisy)Poir. has an androecium of five antipetalous fascicles, consisting of four stamens each. The stamen fascicles alternate with five indented nectary scales. A SEM-study of the floral development, as well as a study of the floral anatomy was carried out to understand whether the nectariferous scales represent staminodia or are receptacular in nature and consequently whether or not the androecium ofHarungana, and theClusiaceae in general, is originally diplostemonous. The five petals originate by the splitting of petal-stamen complexes. Next the upper part of each complex differentiates basipetally in four stamens. The stamens remain fascicled and are lifted on a long stalk at maturity. Five carpel primordia are initiated united in a low ringwall. The five nectary scales appear after carpel inception and develop an external morphology reminiscent of anthers. The floral anatomy reveals an independent origin of sepal median traces and common sepal lateral traces, free petal traces, stamen fascicle traces and alternating vascular tissue which supplies the nectaries. The petal-stamen complexes are the result of a retardation in petal inception, linked with the absorption of petal tissue into the stamen primordia. The development of the stamen fascicles is discussed; it is suggested that they are of a secondary nature and do not appear as a reduction from a multistaminate androecium. The external morphology and vascular anatomy of the scales speaks in favour of a staminodial nature. The comparison with some other species of theClusiaceae gives evidence of a diplostemonous ancestry of the androecium.
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 32 (1991), S. 334-340 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Normal phase separations ; Cyanopropyldimethyl silica ; Chloro-added polycyclic aromatic hydrocarbons ; Environmental samples
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Retention characteristics in normal phase HPLC of highly biologically active chloro-added polycyclic aromatic hydrocarbons (PAHs) were studied. Silica, cyanopropyldimethylsilyl- and aminopropylsilyl- modified stationary phases were investigated. Retention properties of chloroadded PAHs on these phases were shown to be strongly influenced by the number of chloro-additions. This is due to the strong polarity of the methylene carbon at the chloro-addition site. Active silica had a strongly degrading effect on the unstable chloro-added PAHs during separation. Aminopropylsilica did not exhibit sufficient selectivity towards chloro-added PAHs when compared to chlorosubstituted PAHs. Cyanopropyldimethylsilica was shown to be applicable to a group separation of chloro-added and chloro-substituted PAHs. A fast clean-up procedure for chloro-added PAHs in complex samplesis outlined. It involves an initial elimination of more polar substances on a short open column with strongly deactivated silica and a subsequent separation on a cyanopropyldimethylsilyl HPLC column in normal phase mode.
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 32 (1991), S. 345-349 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Column packings ; Pore size distribution ; Diffusion and adsorption ; Band broadening
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The complex intraparticle structure typical of chromatographic column packings has been analyzed by use of an equivalent network model which emphasizes pore size distribution and connectivity. Special attention is given as to the way in which diffusion and adsorption interact and display modified peak spreading characteristics according to the morphology of the pore space. This study reveals a very significant increase in the column band broadening over that expected from physical adsorption which can arise from particular distributions of pore sizes. This has implications for designing packings which take advantage of the separating power due to adsorption but do not compromise the resolution of the chromatographic system.
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  • 9
    ISSN: 1615-6102
    Schlagwort(e): Angiosperms ; Cell cycle ; Double fertilization ; Endosperm ; Ephedra
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Fertilization inEphedra trifurca was examined with a combination of light and fluorescence microscopy. Developmental analysis clearly indicates that double fertilization events, similar to those described inE. nevadensis, regularly occur during the process of sexual reproduction inE. trifurca. In addition to the typical fusion of a sperm nucleus and egg nucleus, a second fertilization event occurs between the second sperm nucleus from an individual pollen tube and the ventral canal nucleus. Both of the fertilization events take place within the confines of an individual egg cell of the female gametophyte. Microspectrofluorometric data demonstrate that each nucleus involved in a sexual fusion event proceeds through the synthesis phase of the cell cycle and increases its DNA content from 1C to 2C before the process of nuclear fusion is completed. Photometric data also confirm that the product of the second fertilization event is equal in DNA content (4C) to the zygotic nucleus derived from the first fertilization event, and is prepared to enter into mitosis as a fully functional diploid nucleus.
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Pharmacy world & science 13 (1991), S. 70-73 
    ISSN: 1573-739X
    Schlagwort(e): Algae ; Angiosperms ; Arthropods ; Bacteria ; Fungi ; Lichens ; Marine animals ; Quinones, naturally occurring
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Angiosperms, fungi (including lichens), and bacteria are the main sources of natural quinones. Small numbers are present in algae, ferns, conifers, sponges, echinoderms, other marine animals, and arthropods. In angiosperms quinones have some chemotaxonomic value at the genus and family level but more surveys are required.
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  • 11
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Cactaceae ; Echinocereus ; Natural hybridization ; systematics ; dioecy ; flavonoids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The origin ofEchinocereus ×lloydii Britt. & Rose, pro sp. (Lloyd's Hedgehog Cactus) was investigated using comparative morphology, cytology, biochemistry, and particularly, artificial hybridization. Numerous artificial crosses between the putative parentsE. coccineus Engelm. (a species of claret-up cactus) andE. dasyacanthus Engelm. (Texas Rainbow Cactus) were successful, resulting in the production of hundreds of seeds with hybrid embryos. The F1 hybrid progeny (i.e., syntheticE. ×lloydii) grew to sexual maturity in about four and one-half years, whereupon successful backcrosses and F2 generation hybrids were also obtained. The known F1 hybrids closely approximated naturalE. ×lloydii. The fertility of these syntheticE. ×lloydii was high, like their natural counterparts. The populations ofE. ×lloydii in Pecos County, Texas are inferred to have originated as the result of natural interspecific hybridization. It is assumed thatE. ×lloydii or similar plants may arise wherever the parental taxa grow sympatrically.
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 178 (1991), S. 125-134 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Annonaceae ; Allozymes ; genetic variation ; systematics ; evolution in tropical woody plants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Five species ofAnnona and one species fromArtabotrys, Cananga, Polyalthia, andRollinia were investigated in regard to 11 different allozyme loci. Preliminary studies on small population samples ofAnnona suggest genetic uniformity in three species and variability within and between populations in two other species. The allotetraploid origin ofA. glabra is clearly shown by its hybrid enzyme bands. The genetic distance between fiveAnnona species partly corresponds with their morphological relationships; onlyA. muricata appears more separated than is suggested by morphology. A comparison of the five genera demonstrates close relationship betweenAnnona andRollinia. Two enzyme loci are identical within all taxa investigated and possibly may serve as a genetic marker for the family.
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 1-4 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Zingiberaceae ; Globba ; Taxonomy ; Flora of Malesia and Malaysia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Based on personal collections ofGlobba unifolia Ridl. andG. unifolia var.sessiliflora Holtt., the latter is recognized as a distinct species. As the nameG. sessiliflora is already occupied, the nomen novumG. corneri is proposed in honour of Prof. DrE. J. H. Corner, who was the first collector of the plant.
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 5-16 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Caryophyllaceae ; Scleranthus ; Floral morphology ; within-population crosses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract I used a discontinuous population ofScleranthus annuus (Caryophyllaceae) to study the effect of crossing distances on flower morphology of the progeny. Four types of progeny were produced by artificial selfing, crossing with pollen-donors from the same patch in the population, crossing with pollen from donors from other patches in the population and inter-population crosses. The size of gynoecium parts and 12 sepal characters in this petal-lacking species were significantly influenced by the type of cross and the patch in the population from where the seed-parents originated. All comparisons of progeny types except selfed vs progeny produced by within-patch crosses were significantly separated from each other, while all four seed-parent patches used were significantly separated in a multidimensional space.
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 17-35 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Solanaceae ; Nierembergia ; Tapinotaspis ; Centris ; Lanthanomelissa ; Paratetrapedia ; Pollination biology ; oil-flowers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A morphological and anatomical description of the floral syndrome ofNierembergia is given, including a survey of the presence of elaiophores in most of its species, chromatography of the floral oils and observations on the pollinator behaviour. The principal pollinators areTapinotaspis spp. includingT. chalybaea which is endowed with oil collectors on the middle legs. Other exomalopsines (Lanthanomelissa andParatetrapedia) and centridines (Centris) also visitNierembergia for pollen and oil. Based on these observations and on a morphological study of the fertile parts, different pollination modes are recognized and the biogeography and evolution of the genus is discussed.
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  • 16
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Leguminosae ; Medicago truncatula f.laxicycla ; M. laxispira ; Evolution ; adaptation ; seed germination ; chromosome number ; Flora of Libya
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Medicago truncatula is a member ofMedicago sect.Spirocarpos, in which all 34 species have coiled fruit, usually tightly coiled, that permanently retain the seeds. A variant ofM. truncatula from Libya is unique for the species in possessing very loosely coiled fruits, and is here recognized as a new forma,M. truncatula f.laxicycla E. Small. In germination tests of a number of species ofMedicago, the unusual Libyan variant proved to be the only one in which rapid and simultaneous germination of most of the seeds occurred while still within a fruit. The loose coiling of the fruit of the Libyan variety appears to facilitate water entry and seedling escape. Its rapid germination might adapt it to respond quickly to intermittently available moisture, but at the cost of abandoning the strategy of intermittent germination adopted by other populations ofMedicago sect.Spirocarpos.
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 47-66 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Poaceae ; Hordeum patagonicum complex ; barley ; Classification ; numerical methods ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Seeds of theHordeum patagonicum complex were collected from the field and grown in the greenhouse. The aim was to take a sample of members of the complex, and on the basis of the phenotypic similarities in some morphological and physiological characters, determine whether distinct groups exist. When cluster analyses, to generate hypotheses, and orthodox statistical procedures, for hypotheses obtained a priori, were applied to the reproductive morphology, germination and flowering patterns, onlyH. patagonicum subsp.magellanicum, out of the five recognized taxa, could be distinguished consistently. The remaining four taxa, which overlapped considerably, could be re-formed into three groups whose centroids were different but whose ranges of variation were not distinct from each other. We conclude that the highly cross-compatible members of theH. patagonicum complex, first defined as species and later redefined as subspecies are probably no more than biotypes.
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 75-82 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Poaceae ; Triticeae ; Elymus ; Hordeum ; Intergeneric hybrids ; genome analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The results of genome analysis of five hybrids, viz.Elymus patagonicus ×Hordeum procerum, E. patagonicus ×H. tetraploidum, E. angulatus ×H. jubatum, E. angulatus ×H. lechleri, andE. angulatus ×H. parodii, are reported. The genomic constitution ofHordeum tetraploidum andH. jubatum is best given as H1H1H2H2, ofH. lechleri andH. parodii as H1H1H2H2H4H4, ofH. procerum as H1H1H2H2H3H3, and ofElymus patagonicus andE. angulatus as SSH1H1H2H2.
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 67-73 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Campanulaceae ; Campanula isophylla ; C. elatines ; C. elatinoides ; C. fragilis subsp.fragilis and subsp.cavolinii ; C. garganica ; C. fenestrellata subsp.istriaca ; C. portenschlagiana ; Allozyme variation ; heterozygosity ; Flora of Italy and W. Jugoslavia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Variability and genetic divergence of 11 field populations of seven species of theCampanula elatines andC. fragilis rock-plants group from the Mediterranean and pre-Alpine areas have been studied by starch-gel electrophoretic techniques.Campanula isophylla, C. elatines, C. elatinoides, C. fragilis subsp.fragilis and subs.cavolinii, C. garganica were collected in Italy, whilstC. fenestrellata subsp.istriaca andC. portenschlagiana came from W. Jugoslavia. Twelve enzymatic loci for each population were genetically analysed: PGI-1 and 2, PGM-2, IDH-1 and -2, SKDH, ME, ADH, GOT-2, MPI-1 and -2, SOD-1. The genetic distances among the above mentioned entities have been calculated by Nei's index and depicted in a dendrogram.
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 83-91 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Labiatae ; Teucrium sect.Chamaedrys ; Taxonomy ; trichomes ; Flora of Italy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Micromorphology and distribution of trichomes (both secretory and not) in different parts of plants of the five Italian species belonging toTeucrium sect.Chamaedrys have been studied. These characters neatly evidence the differences between the taxa considered; of particular interest are the observations concerning the dense coverage of peltate hairs on the abaxial face of the leaves ofT. flavum subsp.glaucum and the characters contributing to a better identification ofT. marum andT. subspinosum. The importance of the calyx indumentum as distinctive taxonomical character of the genusTeucrium is confirmed, stressing at the same time the necessity of completing the observations at micromorphological level.
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 93-101 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Orchidaceae ; Myrosmodes cochleare ; Pollination ; breeding system ; Andes of Venezuela
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Myrosmodes cochleare is a terrestrial orchid restricted to high elevations of the northern Andes. It is self-compatible but not autogamous. Flowering begins at the apex of the inflorescence, but flower size increases steadily towards the base. Fruit set of selfed flowers was found to increase significantly from the apex to the base of the inflorescence. Open-pollinated fruit set was significantly lower than hand-pollinated fruit set overall, but the highest levels occurred in the middle of the inflorescence. Eumenid wasps and a calliphorid fly were observed to pollinate the flowers, but visits were rare and occurred only during infrequent warm periods.
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 103-108 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Poaceae ; Triticeae ; Kengyilia habahenensis ; spec. nova ; Taxonomy ; genome analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Kengyilia habahenensis, spec. nova, from the Altai mountains, China, is described morphologically and cytologically. It has 2n = 42 chromosomes, and the genome formula PYS.
    Materialart: Digitale Medien
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 109-114 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Rhamnaceae ; Condalia ; Lipid analysis ; seed protein electrophoresis ; chemical variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Seed oil composition (sterol esters and sterols) and seed protein profiles ofCondalia microphylla were investigated. The chemical differences observed may be attributed to genotypic changes and could support the existence of infraspecific taxa.
    Materialart: Digitale Medien
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 115-123 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Orchidaceae ; Anacamptis pyramidalis ; A. urvilleana ; Polyploidy ; isolation mechanisms ; speciation ; Flora of the Mediterranean ; Malta
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Anacamptis pyramidalis is a variable and wide-spread European-Mediterranean taxon. Beside a dominant cytotype with 2n = 36 it includes cytotypes with 2n = 54 and 63 in northern Tuscany (and the Eastern Pyrenees) and one with 2n = 72 on Malta. In contrast,A. urvilleana, formerly often misidentified and included inA. pyramidalis, is a monomorphic and distinct species, endemic to the Maltese Islands. It has 2n = 36, can be clearly separated by morphological and anatomical features and is isolated from partly sympatric populations ofA. pyramidalis with 2n = 72 by differences in chromosome number, flowering time and habitat preference.
    Materialart: Digitale Medien
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 125-137 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Liliaceae ; Allium schœnoprasum ; C-banding ; karyotype polymorphism ; geographical variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Variation in C-banding was studied in seven populations ofAllium schœnoprasum from eastern N. America, including populations referable to var.sibiricum, var.laurentianum, and ± intermediate. 23 bands were recognized on five pairs of chromosomes, and were treated as 23 loci. No banding site was monomorphic throughout the plants studied. The level of polymorphism per population was 〉60%, and the average heterozygosity values varied from 0.21 to 0.27. The various “banding patterns” of chromosomes were shown to depend on the random combination of individual bands. Nei's genetic distances between populations varied from 0 to 0.070 (mean: 0.033). The matrix of genetic distances was analysed by non-metric multidimensional scaling, and the results showed a significant relationship between longitude and population scores on the ordination. The chromosomal data did not clearly discriminate between the two native varieties ofA. schœnoprasum, but were interpreted as a longitudinal cline. It is suggested that studies of C-banding variation in vascular plants should focus on individual banding sites, rather than on whole chromosome banding patterns.
    Materialart: Digitale Medien
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 139-158 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Gentianaceae ; Gentianella germanica ; Gentianella campestris ; Seasonal dimorphism ; seasonal differentiation ; seasonal ecotypes ; flowering time ; aestival and autumnal vicariads ; grazing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Plant samples were collected from 13 populations of the two speciesGentianella germanica andG. campestris. In addition, two samples from populations of grazed plants lacking their main stems were collected. A number of relevant morphological characters were measured, the flowering time, and the habitats of each population were studied. Some ecotypes ofG. germanica with clear differences in flowering time were recognized. Differences in flowering time and morphology between populations ofG. campestris seem to be clinal. The generally accepted theory of seasonal dimorphism with the assumption of separate aestival and autumnal vicariads proves to be inadequate. A hypothesis based upon the effect of human influences on the origin of this ecotypes is suggested.
    Materialart: Digitale Medien
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 159-169 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Fabaceae ; Arachis batizocoi ; A. hypogaea ; Genome analysis ; phylogenetic relationships
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Arachis batizocoi Krap. & Greg. is a suggested B genome donor to the cultivated peanut,A. hypogaea L. Until recently, only one accession of this species was available in U.S.A. germplasm collections for analyses and species variability had not been documented. The objective of this study was to determine the intraspecific variability ofA. batizocoi to better understand phylogenetic relationships in sect.Arachis. Five accessions of the species were used for morphological and cytological studies and then F1 intraspecific hybrids analyzed. Some variation was observed among accessions—for example, differences in seed size, plant height and branch length. The somatic chromosomes of accessions 9484, 30079, and 30082 were nearly identical, whereas, the karyotypes of accessions 30081 and 30097 have several distinct differences. For example, 30081 had significantly more asymmetrical chromosomes 2 and 6 and more median chromosomes 7 and 10, and 30097 had significantly more asymmetrical chromosomes 3 and 10 and more median chromosomes 1 and 5 than accessions 9484, 30079, and 30082. All F1 hybrids among accessions were highly fertile. Meiotic observations indicated that hybrids among accessions 9484, 30079, or 30082 had mostly bivalents. However, quadrivalents were observed when either 30081 or 30097 was crossed with the above three accessions and 30081 × 30097 had quadrivalents, hexavalents and octavalents. The presence of translocations is the most likely cause of multivalent formation inA. batizocoi hybrids. Cytological evolution via translocations has apparently been an important mechanism for differentiation in the species.
    Materialart: Digitale Medien
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 183-195 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Polygonaceae ; Rumex acetosa ; R. acetosella ; Sex ratios ; spatial segregation of the sexes ; environmental correlations ; density effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Populations ofRumex acetosa andR. acetosella were studied during two growth seasons. The ramet sex ratios ofR. acetosa were always female-biased. InR. acetosella the sex ratios expressed more variation but were mostly female-biased. In both species the sex ratios commonly varied between subpopulations reflecting a partial spatial segregation of the sexes. No marked differences between sexes in vegetative vigour were detected in either species. Interactions between sex ratios, various soil characteristics and population densities were determined. Possible mechanisms for causing biased sex ratios and partial spatial segregation of the sexes are discussed.
    Materialart: Digitale Medien
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 197-211 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Rubiaceae ; Rubieae ; Asperula sect.Oppositifoliae ; sect. nova ; spec. novae:A. rezaiyensis ; A. rechingeri ; Galium spec. novae:G. anguineum ; G. azerbayjanicum ; G. plurifolium ; G. pseudomegalanthum ; G. kandavanense ; G. wendelboi ; G. sojakii ; G. subvelutinum var.oligotrichum ; var. nova ; G. decumbens ; G. problematicum ; stat. nov ; Flora of Iran
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Asperula sect.Oppositifoliae is validated. 2 new species ofAsperula and 7 new species and 1 variety ofGalium from Iran are described, discussed in respect to their affinities and illustrated. 2 subspecies are raised to species rank.
    Materialart: Digitale Medien
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 175 (1991), S. 1-10 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Iridaceae ; Tigridieae ; Leaf anatomy ; systematics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Leaf anatomy is described in 32 species of 16 genera of the New World tribeTigridieae (Iridaceae, Iridoideae), including examples from both subtribesCipurinae andTigridiinae. Both plicate (pleated) and foliated (with flanges, or keel extensions) leaf types occur in both subtribes. However, amongTigridiinae, foliated leaves are restricted toTigridia and differ from the foliated leaves ofCipurinae in that they lack subepidermal marginal sclerenchyma, which is present in all the foliated species ofCipurinae. This indicates that the foliated leaf type has evolved at least twice in the tribe, since the plicate leaf, which most closely resembles the equitant leaf typical ofIridaceae, is probably plesiomorphic.
    Materialart: Digitale Medien
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 174 (1991), S. 213-220 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Orchidaceae ; Platanthera bifolia ; Embryology ; embryo sac ; megasporogenesis ; megagametogenesis ; confocal scanning laser microscopy (CSLM)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Flowers ofPlatanthera bifolia were hand-pollinated and fixed in FPA50 after 2, 5, 7, 14, and 21 days. Ovules, made transparent in Herr's clearing fluid, were investigated using confocal scanning laser microscopy. Pollination initiates the megasporogenesis. Two days after pollination dyads are frequent. Three days later most embryo sacs contain two nuclei. Seven days after pollination the embryo sacs are 4–8-nucleate and some are organized, and a week later all embryo sacs are organized and fertilization takes place. The embryo sac development follows thePolygonum type. Twenty-one days after pollination the egg nuclei have been fertilized and the embryo sacs contain 2- to many-celled embryos. A suspensor is formed during early stages of embryo development but degenerates later. Fertilization of the central nucleus does not lead to endosperm development.
    Materialart: Digitale Medien
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 175 (1991), S. 11-21 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Leguminosae ; Cicer ; Allozymes ; isozyme gene duplication ; phylogenetic relations ; polymorphism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Allozymic variation at 30 isozyme loci was examined electrophoretically in nine annual and one perennial species ofCicer. While most of the accessions examined were monomorphic, species can be differentiated on the basis of their enzyme phenotypes. Several groups of species were identified based upon genetic distance values. For example,C. arietinum, C. reticulatum, andC. echinospermum shared the same alleles for most of the loci exmained. PerennialC. anatolicum is also closely related to this group. Similarly,C. judaicum, C. bijugum, andC. pinnatifidum formed another group. Two annual species,C. chorassanicum andC. yamashitae clustered together, whereasC. cuneatum was the most distantly related species. Correlations were found between genetic distances and geographic distribution. Results from enzyme electrophoresis tend to support the previously reported taxonomic treatments based upon crossability and morphological similarity. However,C. yamashitae, which has been classified in the second crossability group, is quite distinct genetically and morphologically from the remaining species of the group. An isozyme gene duplication observed in the genus suggested the monophyletic origin of the species examined in the present study.
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 175 (1991), S. 39-54 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Rubiaceae ; Chloroplast DNA ; fragment analysis ; restriction analysis ; site analysis ; Wagner parsimony
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Information from the same restriction analysis of chloroplast DNA of 33 taxa ofRubiaceae was scored in four different ways, two of which were based on fragments, and two on restriction sites, and they were subsequently analysed with Wagner parsimony. The methods resulted in different phylogenetic trees. The inherent differences between the methods relate to the amount of non-homologous characters and dependent characters, but none of the methods will systematically bias the resulting cladograms. The fragment analyses are much less time-consuming, but probably less accurate, than the site analyses. The choice of method is dependent on a trade-off between accuracy and resources (time). One important recommendation is made: all phylogenetic analyses of chloroplast DNA data should be accompanied by a data matrix and contain information on how the matrix was compiled.
    Materialart: Digitale Medien
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 175 (1991), S. 55-72 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Orchidaceae ; Dactylorhiza ; D. maculata ; D. fuchsii ; D. saccifera ; D. caramulensis ; Biostatistics ; multivariate analysis ; taxonomy ; morphology ; Flora of Western-Europe
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Multivariate analysis tools are exploited on a data set composed of quantitative characteristics collected on 35 populations of plants of theDactylorhiza maculata (L.)Soó group from Western-Europe. These samples lead to four well-defined clusters; this, together with qualitative, cytological and ecological arguments, allows for the recognition of four specific entities:D. maculata s.str.,D. fuchsii (Druce)Soó,D. saccifera (Brongn.)Soó andD. caramulensis (Vermeulen)Tyteca. It is concluded that the floral characters play an essential role in the taxonomical distinction. It also appears that the set of characters measured, as well as the methods exploited, are especially well-suited and valuable tools for the morphological study of the genusDactylorhiza.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 175 (1991), S. 73-86 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Hyacinthaceae ; Ornithogalum subg.Heliocharmos ; O. angustifolium ; O. divergens ; O. monticolum ; O. tenuifolium ; O. umbellatum ; Numerical taxonomy ; systematics ; evolution ; Flora of France
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Macromorphological variation within theOrnithogalum umbellatum L. (Hyacinthaceae) complex in France was studied. The resulting data were treated by numerical taxonomy methods. Three morphs can be identified: one corresponding to diploid plants, another made up of triploids and a third which encompasses plants having ploidy level above 3x (4x, 5x, and 6x). A systematic interpretation of the complex is proposed wherein only one species,O. umbellatum, is retained. This species corresponds to a polyploid complex undergoing evolution.
    Materialart: Digitale Medien
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 175 (1991), S. 87-92 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Compositae ; Eupatorieae ; Mikania ; Mikania swartziana complex ; Dioecy ; Flora of the Greater Antilles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract For the first time dioecy inMikania and in the tribeEupatorieae is described and discussed. The condition is known only in members of theMikania swartziana Griseb. complex, a group of eight species, all endemic to the Greater Antillean Islands of Cuba, Hispaniola, and Jamaica.
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 175 (1991), S. 93-99 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Pennisetum ruppellii ; Pulmonaria longifolia ; Papaver somniferum ; Triploidy ; infragenomic chromosome pairing ; chromosome morphology ; isozyme numbers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The genomic evolution of triploid plants with regular bivalent formation is discussed. The conclusion is reached that although all the progeny of an originally triploid individual will be triploid numerically, only part of the progeny will be triploid genomically. The consequences of this for triploid identification by means of chromosome morphology and isozyme numbers is discussed.
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 175 (1991), S. 101-114 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Archamamelis ; Hamamelidaceae ; Hamamelidales ; Hamamelididae ; Cretaceous flowers ; Cretaceous pollen ; Palaeoflora of Sweden
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Lignite fossil flowers (including pollen) and isolated stamens of probable hamamelidalean (possible hamamelidaceous) affinities from the upper Cretaceous (Late Santonian or Early Campanian) of Sweden are described. The flowers are 6–7-merous with probably a double perianth, one whorl of stamens and (2-?)3 carpels. The stamens are disporangiate; each theca opens by a valve towards the centre of the flower. Pollen is tricolpate, tectate-columellate and reticulate; the endexine is lamellated in the apertural region. The gynoecium has free styles and a syncarpous ovary. In the one flower that was serially sectioned the ovary is either non-functional or development of the few (2?) ovules is retarded.
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  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 175 (1991), S. 125-138 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Asteraceae ; Helianthus niveus ; H. petiolaris ; Morphological intergradation ; speciation ; restriction-site variation ; gene lineage analysis ; plant taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Helianthus petiolaris andH. niveus are polytypic species which are morphologically distinct at the periphery of their ranges but intergrade in areas of sympatry.Helianthus niveus includes both annual and perennial members, whereasH. petiolaris is strictly annual. Chloroplast DNA and nuclear ribosomal DNA restriction site data were used to reconstruct the evolutionary history of populations of the two species. Cladistic analyses reveal the following: (1) neither species is monophyletic; (2) the annual habit is derived once in this complex; and (3) the region of morphological intergradation appears to be primary in origin. The significance of interbreeding versus common descent in defining species concepts is discussed in relation to the above cladistic analyses.
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  • 40
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Salicaceae ; Populus tremuloides ; Alpine community ecology ; clonal organisms ; DNA fingerprinting ; population genetics ; rflp analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A recently developed class of DNA endonuclease fragment probes (variously termed “minisatellite,” “DNA fingerprinting,” or “variable number tandem repeat loci” probes) has detected extensive intraspecific genetic variation in tetrapods. Here we use one probe from this class, the M 13 repeat probe (shown previously to yield ”DNA fingerprints” in humans) to examine genetic diversity in the quaking aspen. Comparisons of endonuclease fragment profiles of individuals separated by at least 6km reveals that diversification of alleles in this species has occurred to such an extent that the likelihood of two randomly chosen individuals having indistinguishableHaeIII fragment profiles is c. 3.17 × 10−4. Based on this finding, members of interdigitating clones can be assigned to one or another clone with high statistical confidence. Interdigitating, morphologically cryptic clones were also identifiable. These results demonstrate that some minisatellite probes can be applied to very distant taxa to obtain useful information about genetic variation.
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 175 (1991), S. 139-160 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Restionaceae ; Rhodocoma ; Speciation ; phylogeny ; culm anatomy ; rhizome anatomy ; morphology ; taxonomy ; Flora of Africa
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The vegetative and reproductive morphology, culm and rhizome anatomy and seed surface micromorphology ofRhodocoma are described. It is shown that this variation is best contained by recognizing three new species in the genus. These new taxa are described, and the phylogeny of the genus is investigated by cladistic analysis. The environmental parameters and distributions of the species are related to the cladogram. This suggests that the species are at present ecologically separated, and indicates that the speciation may have been sympatric. This is the first support for the hypothesis that sympatric speciation may have been important in the speciose Cape flora.
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 176 (1991), S. 11-20 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Cruciferae ; Glucosinolates ; chemotaxonomy ; GC analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Seventeen glucosinolates were identified and quantified by micro-scale GC analysis in Algerian samples fromSisymbrieae, Arabideae, Lepidieae, andBrassiceae tribes of theCruciferae. Major glucosinolates and their amino acid precursors allowed species to fall naturally into tribes as classified byJanchen.
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 175 (1991), S. 161-223 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Orchidaceae ; Coryciinae ; Ceratandra ; Evota ; Evotella ; Ommatodium ; Pterygodium ; Anochilus ; Corycium ; Morphology ; phylogeny ; cladistics ; phytogeography ; speciation ; classification ; Flora of southern Africa
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The leaf-anatomy, palynology, seed-morphology, vegetative morphology and especially the highly complicated floral morphology of theCoryciinae s. str. (Diseae: Orchidoideae: Orchidaceae) are described and illustrated in detail. On the basis of these characters the presumed phylogeny, based on a rigorous cladistic analysis, is presented. The cladistic biogeographical analysis of theCoryciinae s. str. shows that it is a member of the Afrotemperate Track, with a pattern of vicariance events typical of the members of this track. An analysis of the patterns of speciation shows that allopatric speciation appears to be rare, and that parapatric speciation across edaphic boundaries may be the most important factor. Proceeding from the information presented, a new classification of the group is proposed in which we recognize the four generaCeratandra, Evotella, Pterygodium andCorycium. The new monotypic genusEvotella comprises a species originally described asPterygodium rubiginosum. The three species of the genusAnochilus are transferred toCorycium andPterygodium. P. magnum, which was originally described asPterygodium but was transferred toCorycium lately, is placed in a monotypic section ofPterygodium.
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 176 (1991), S. 1-10 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Chenopodiaceae ; Beta bulgaris L ; Germplasm collections ; taxonomy ; single linkage cluster analysis ; principal component analysis ; variation patterns
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The objective of this study was to contribute to a better understanding of the variation pattern in leaf beets. 42 biennial samples from a total of 74 entries were described by 17 characters. A group of presumably less selected leaf beets (group A) with narrow petioles was separated from more advanced cultivars by single linkage cluster (SLCA) and principal component analysis (PCA). SLCA sorted the more advanced cultivars into two groups (B and C) based on a simply inherited trait, the leaf colour. These two groups could virtually not be discerned by PCA. Group A contained germplasm similar to provar.vulgaris sensuHelm whereas accessions within group B and C did not easily fit into provar.flavescens. It seems that classical taxonomy does not predict the features of leaf beets precisely enough. It is suggested that this problem can be solved by replacing classical taxonomy in the case of leaf beets by a descriptive database.
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 176 (1991), S. 21-31 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Poaceae ; Systematics ; phylogeny ; chloroplast DNA reassociation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Sequence variation in chloroplast DNA (cpDNA) as measured by DNA reassociation was examined in 12 grass species to address systematic problems in thePoaceae at the subfamilial and tribal levels. Two species,Petunia (Solanaceae) andGlycine (Leguminosae), were included to determine degrees of sequence divergence in cpDNA between monocots and dicots. The data were analyzed phenetically and phylogenetically. Species were segregated into four major groups that corresponded to the subfamiliesPooideae, Oryzoideae, Chloridoideae, andPanicoideae. Representatives of thePooideae andOryzoideae grouped together as did members of theChloridoideae andPanicoideae. ThePooideae split into two major groups corresponding to the recently recognized supertribesTriticanae andPoanae. Internodes between subfamily branches were short which might indicate a burst of divergence in the family early in its evolution. Sequence similarity values between the monocot grass species and the two dicot taxa ranged from 0.15 to 0.27, representing the highly conserved sequences of the chloroplast genome.
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 176 (1991), S. 53-61 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; monocotyledons ; Orchidaceae ; Cephalanthera ; Allozymes ; electrophoresis ; genetic variation ; breeding type
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The genetic variation of seven enzymes for a total of nine loci was investigated in three species of terrestrial orchids of the genusCephalanthera:C. longifolia, C. rubra, andC. damasonium. These species are characterized by presenting different breeding types: outbreeding , outbreeding with facultative vegetative reproduction, and inbreeding, respectively. Electrophoretic evidence points to a difference in the behaviour of each of the three species which seems strictly related to the breeding type. On the basis of our resultsC. longifolia behaves as a normal outbreeder, whileC. rubra presents the influence of vegetative reproduction in some populations and not in others.C. damasonium shows a total lack of both among and within populations genetic variation, which is most probably due to the autogamic breeding type.
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 176 (1991), S. 63-74 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Bromeliaceae ; Tillandsia pallidoflavens ; Microsporogenesis ; organelle ultrastructure ; plastids ; periodic acid-thiocarbohydrazine-silver proteinate staining
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract InTillandsia pallidoflavens none of the organelles undergoes fundamental de- and redifferentiation during microsporogenesis. The plastids are amoeboid, exhibit complex internal structures and gradually start accumulating polysaccharides from meiotic prophase I onwards. These observations contradict reports for other taxa. The ultrastructure of mitochondria and dictyosomes, respectively, is more or less orthodox. The extensive ER, which is only poorly stained by standard methods was identified by image intensifiying techniques. The ribosomes are not only associated with the ER or occur as polyribosomes free in the cytoplasm, but can also form more or less dense clusters.
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 176 (1991), S. 75-123 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Asteraceae ; Inuleae s. str. ; Cladistics ; phylogeny ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The interrelationships of the tribeInuleae s. str. have been analysed with a computerized parsimony program (Hennig 86), using theArctotideae as functional outgroup. The results are illustrated with a cladogram and a strict consensus tree. A detailed character discussion is presented. Descriptions of all genera are supplied with brief notes on distribution, references to chemical investigations, and chromosome numbers. Lists of recognized species are also presented in connection to each genus, respectively. 21 new combinations are made, one new genus,Xerolekia A. Anderb., is described,Mollera is reduced to a synonym ofCalostephane, and the genusDuhaldea is resuscitated.Anisopappus was found to be a paraphyletic basal group in the tribe. The paleate generaAsteriscus, Nauplius, Ighermia, Buphthalmum, andXerolekia form one monophyletic group,Inula and other, similar genera were found to constitute the ancestral complex of thePulicaria group.
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 176 (1991), S. 125-131 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Polygonaceae Aconogonon campanulatum ; Heterostyly ; floral dimorphism ; pollination ; dioecy ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Heterostyly is clearly confirmed inAconogonon campanulatum. This distylous species is dimorphic for tepals, styles, stigma surface, stamens, pollen grain size, and pollen sexine ornamentation. The floral shape is campanulate and thrum flowers are slightly larger than pin flowers. Small solitary bees were observed as flower visitors and probably effected pollination. The possible evolution of dioecy via heterostyly within the genusAconogonon is discussed.
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 176 (1991), S. 135-143 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Primulaceae ; Cyclamen hederifolium ; C. africanum ; C. purpurascens ; Chromosome numbers ; karyotypes ; ploidy levels
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Although theCyclamen subg.Cyclamen spp. are morphologically variable, previous studies suggest a superficial cytological uniformity. New chromosome numbers and an indication of karyotypic instability are reported inC. hederifolium andC. africanum that reveal that the cytology of the subgenus is more complicated than previous accounts suggest. The possible significance of these phenomena is discussed. The diploid status ofC. purpurascens has been confirmed and a distinction between the three diploid karyotypes has been described. The cytological variation may help to explain the well documented morphological variation exhibited in these species.
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 176 (1991), S. 145-177 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Asteraceae ; Plucheeae ; Cladistics ; phylogeny ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The tribePlucheeae (Benth.)A. Anderb., has been analysed cladistically by means of a computerized parsimony program (Hennig 86), using theArctotideae as outgroup. The results of the analysis are presented in a consensus tree and one cladogram. Four major monophyletic subgroups can be recognized: TheColeocoma group (3 genera), thePterocaulon group (3 genera), theLaggera group (6 genera), and thePluchea group (12 genera). All recognized genera are described and most genera are supplied with taxonomical notes including comments on their taxonomic status. Genera such asBlumea, Pluchea, andEpaltes are demonstrated to be unnatural assemblages.Monarrhenus andTessaria are both closely related to thePluchea complex. The old generic nameLitogyne Harv. has been taken up for one species ofEpaltes, the genusRhodogeron is reduced to a synonym ofSachsia, and the following new combinations are made;Litogyne gariepina (DC.)A. Anderb., andSachsia coronopifolia (Griseb.)A. Anderb.
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 176 (1991), S. 179-203 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; dicotyledons ; Urticaceae ; Pilea pumila ; Urtica dioica ; Guttation ; hydathodes ; leaf anatomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Laminar hydathodes are known from only three dicot families. InUrticaceae they are associated with minor vein junctions in all five tribes, as surveyed from cleared leaves of 43 species in 30 genera. Only one species lacked hydathodes. Exclusively adaxial hydathodes were found in 28 genera. In tribeElatostemeae, laminar hydathodes inPilea andPellionia species are abaxial, adaxial, or on both surfaces. Guttation was observed in four species.Urtica dioica (adaxial) andPilea pumila (abaxial) were studied anatomically in detail. Hydathodes in the former have normal bundle structure but xylem gaps sometimes occur. In the latter, phloem is displaced in three previously undescribed ways: 1) ends abruptly near hydathode, 2) curves into connecting vein at adjacent junction, or 3) departs xylem, skirts hydathode independently, and rejoins adjacent xylem strand. Laminar hydathodes are a unifying character of theUrticaceae, and they also strengthen its close relationship to theMoraceae.
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 176 (1991), S. 221-225 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Papaveraceae ; Fumaria ; Phenetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A paper byWilson & al. (1990) on the taxonomy ofFumaria is commented upon. It is concluded that the lack of congruence between the authors' results and evidence from morphology, chemistry, and crossing experiments renders their approach questionable.
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 177 (1991), S. 1-10 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Fumariaceae ; Sarcocapnos ; Systematics ; chorology ; Mediterranean area
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A biometric study of theSarcocapnos crassifolia complex from eastern Andalusia (Spain), Algeria, and Morocco was carried out. Twentytwo populations were used in a principal components analysis based on 14 variables. The results support the recognition of two species,S. crassifolia andS. pulcherrima, spec. nova. The taxon described byBoissier asS. speciosa (S. crassifolia subsp.Speciosa) is maintained inS. crassifolia.
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 177 (1991), S. 11-16 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Chenopodiaceae ; Stomata ; phylogenetic pathways
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A new stomatal type—paracytic mesoperigenous—which has not been separated from the paracytic mesogenous type in previous studies of theChenopodiaceae, is described. The frequent occurrence of this previously unknown paracytic mesoperigenous type in this family is demonstrated. As a result a new phylogenetic pathway between anisocytic mesoperigenous and paracytic mesogenous types may be drawn.
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 177 (1991), S. 17-26 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Lamiaceae ; Satureja group ; Calamintha menthifolia ; Glandular trichome development ; essential oils ; systematics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Plant material ofCalamintha menthifolia was collected from two populations grown in the Vikos-Aoos area (NW. Greece). The structure and ontogeny of the glandular trichomes and the chemical composition of the secreted essential oil were studied. The leaves ofC. menthifolia have numerous glandular trichomes of three morphological distinct types: 1) glandular scales with a unicellular foot and stalk, and a 12-celled head, 2) glandular hairs with a unicellular foot and stalk, and a unicellular pear-shaped head and 3) glandular hairs with a unicellular foot, a bicellular stalk and a unicellular elongated head. Qualitative and quantitative GC-MS analyses of the essential oils revealed piperitone oxide as the main constituent in both populations. In the light of these results the relationships beweenC. menthifolia and other members of theSatureja group as well as its taxonomy are discussed.
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 176 (1991), S. 227-253 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Asclepiadaceae ; Pollination ultrastructure ; tube germination ; autogamy ; floral biology ; floral structures
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung An sieben Asclepiadaceen-Arten wird der Zusammenhang von Blütenstrukturen mit dem Bestäubungsprozeß untersucht. Die Analyse erfaßt die Bandbreite von einfacher organisierten (Secamone) bis zu hochdifferenziertenAsclepiadaceae, wobei neben dem offenen Blütentyp auch zwei Formen von geschlossenen Blüten (Sisyranthus, Microloma) untersucht werden. Die Blüten weisen unterschiedlich stark elaborierte Strukturen auf, die als Führungshilfen für den Insektenrüssel dienen. Neben der eigentlichen Leitschiene, die teilweise einen hohen Grad an innerer Differenzierung besitzt, sind vor allem Haare und Coronastrukturen an der primären Führung des Bestäuberrüssels beteiligt. Die interstaminale Lage der Nektarien sowie ihr Hinaufreichen bis zur Leitschiene sichert ebenfalls das Zurückziehen des Rüssels durch die Leitschiene. Die Einführung des Rüssels in den Spalt des Klemmkörpers erfordert einen relativ festen Sitz des Corpusculums, der in den hier untersuchten Arten auf drei verschiedenen Wegen erreicht wird: Anheftung an den Antherenrändern, basales Ankleben am Griffelkopf und Fixierung durch einen distalen Vorsprung des Griffelkopfes. MitTylophora spec. wird ein Fall vorgestellt, bei dem Fremdbestäubung wie auch Auskeimen der Pollenschläuche in situ und damit vermutlich Autogamie zugleich vorkommen. — Die übertragenen Pollinien werden gewöhnlich in die Narbenkammer eingezogen, dort keimen die Pollenschläuche aus und dringen an der Unterseite des Narbenkopfes in diesen ein. BeiSecamone erfolgt der Eintritt der Pollenschläuche an der Flanke des Griffelkopfes, beiMicroloma ist eine exakte Positionierung des Polliniums unnötig, auch vor der Leitschiene abgelegte Pollinien keimen und senden ihre Pollenschläuche durch die innere Leitschiene zum Griffelkopf. BeiSecamone undTylophora ist ein gemeinsamer Anfang der Griffelkanäle (Compitum) im Griffelkopf vorhanden, die Pollenschläuche werden hier auf beide Ovarien verteilt, auch wenn sie nur von einem einzigen eingeführten Pollinium stammen. Bei den übrigen fünf Arten sind beide Griffelkanäle isoliert voneinander, eine direkte Zuweisung der Pollenschläuche eines Polliniums zu nur einem Ovar ist hier die Regel. Damit verfolgen diese höher evolviertenAsclepiadaceae eher die Strategie der resource allocation, indem sie bei der vorherrschenden Belegung mit nur einem Pollinium durch die strukturell gelenkte Zuweisung der Pollenschläuche auch nur ein Fruchtblatt zur Reife bringen müssen.
    Notizen: Abstract Aspects of floral biology in relation to floral structures are investigated in seven species ofAsclepiadaceae. Pollinaria removal and insertion by the insect pollinator is aided by various structural devices such as hairs or corona elements guiding the proboscis towards the entrance of the anther slit. The nectary is situated directly below this opening, thus increasing the probability of the proboscis being introduced into the anther slit during retraction. The anther slit itself often displays structural differentiation in adaptation to the guiding of the proboscis and the insertion of a pollinium in cross pollination. These mechanisms are highly elaborated so that they work as well in closed flower types, in which the pollinator does not enter the flower directly, but only introduces its proboscis (Sisyranthus, Microloma). A special feature of pollinaria removal is the variety of ways of fixing the corpusculum against the force of the proboscis when it is drawn into the cleft. — The stigma of all species exceptSecamone is located on the lower surface of the stigma head where it is appressed to the filament tube. In some cases a direct contact of the inserted pollinium with the stigmatic surface does not seem to be necessary for pollen tube germination, probably moistening by nectar suffices in these flowers. WithTylophora spec., a case of in situ pollen tube germination has been studied. — Concerning the path of the pollen tubes, two different strategies are followed.Secamone andTylophora develop a structurally defined compitum, while the other five species have strictly divided stylar canals. In these higher evolved species, the pollen tubes of one inserted pollinium are all directed into one ovary only, thus enabling the plant to allocate its resources to one carpel only in the frequent case of fertilization by one pollinium.
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 177 (1991), S. 27-38 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Caryophyllaceae ; Moehringia intricata ; Taxonomy ; morphology ; Flora of S. Spain
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The new taxonMoehringia intricata subsp.giennensis, from the calcareous mountains of the south-eastern Iberian Peninsula is described. A comparative morphological study with regard to the most closely related taxa, contributes information of leaf anatomy, seed and pollen morphology, ecology and distribution.
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 177 (1991), S. 77-80 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Ochnaceae ; Vibrational pollination ; transference of function
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Most members of theOchnaceae possess poricidal anthers that are emptied by pollen collecting bees performing vibrational foraging. In several genera, such asTyleria, Adenarake, and various species ofSauvagesia, however, pollen is released by vibration from the anthers through the porus of a novel structure formed by staminodia. These envelop the androecium and gynoecium. Anthers enclosed in this envelope are often longicidal.
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 177 (1991), S. 53-69 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Asteraceae ; Lactuceae ; Krigia ; Nuclear ribosomal DNA (nrDNA) ; inter-cistronic spacer (ITS) ; intergenic spacer (IGS) ; subrepeating unit ; chloroplast DNA (cpDNA) ; allopolyploid ; restriction site mapping ; methylation ; bootstrap resampling analysis ; sequence divergence value ; cladistics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Restriction site and length variations of nrDNA were examined for 51 populations of seven species ofKrigia. The nrDNA repeat ranged in size from 8.7 to 9.6 kilobase (kb). The transcribed region, including the two ITSs, was 5.35 kb long in all examinedKrigia populations. In contrast, the size of the nontranscribed IGS varied from 3.35 to 4.25 kb. Eight different types of length-variations were identified among the 51 populations, including distinct nrDNA lengths in the tetraploid and diploid populations of bothK. biflora andK. virginica. However, a few variations were detected among populations of the same species or within a cytotype. All populations ofKrigia sect.Cymbia share a 600 bp insertion in IGS near the 18 S gene, and this feature suggests monophyly of the section. AllKrigia spp. had a conjugated type of subrepeat composed of approximately 75 basepairs (bp) and 125 bp. Base modifications in the gene coding regions were highly conserved among species. Forty-five restriction sites from 15 enzymes were mapped, 24 of which were variable among populations. Only four of the variable sites occurred in the rRNA coding region while 20 variable sites were detected in the noncoding regions. Collectively, 25 enzymes generated about 66 restriction sites in each nrDNA; this amounts to about 4.3% of the nrDNA repeat. A total of 50 restriction sites was variable, 28 of which were phylogenetically informative. Phylogenetic analyses of site mutations indicated that two sections ofKrigia, sect.Cymbia and sect.Krigia, are monophyletic. In addition, relationships among several species were congruent with other sources of data, such as cpDNA restriction site variation and morphology. Both length and restriction site variation supported an allopolyploid origin of the hexaploidK. montana. The average sequence divergence value inKrigia nrDNA was 40 times greater than that of the chloroplast DNA. The rapid evolution of nrDNA sequences was primarily due to changes of the IGS sequences.
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 177 (1991), S. 81-91 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Pyrolaceae ; Pyrola ; Moneses ; Floral scent ; intrafloral scent differentiation ; orientation cues ; poricidal anthers ; pollen flowers ; buzz pollination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Floral scent was collected by headspace methods from intact flowers, petals, and stamens of four species ofPyrolaceae. The scent samples were analyzed by coupled gas chromatography-mass spectrometry (GC-MS). The floral scent inPyrola spp. is differentiated into a characteristic petal scent—phenyl propanoids and a characteristic stamen scent—methoxy benzenes. InMoneses the scent is characterized by isoprenoids and benzenoids, with a larger proportion of benzenoids in the stamens compared to the petals. Specific anther scents may promote foraging efficiency in buzz-pollinated species and enhance flower fidelity. Variation in floral scent composition is consistent with the taxonomic relationships among the genera and species examined.
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  • 62
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 177 (1991), S. 111-115 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Styracaceae ; Styrax ; Pamphilia ; Karyology ; chromosomes ; evolution and systematics in tropical woody plants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Chromosome numbers and karyomorphological characters have been investigated inPamphilia andStyrax (Styracaceae). Counted for the first time in the genus, two species ofPamphilia were found to have 2n = 16. The twoStyrax spp. investigated share withPamphilia the same chromosome number, a peculiar condensation behaviour of the chromosomes (Fig. 1a–c) and the same type of semi-reticulate interphase nucleus, results which indicate a close relationship of the two genera. The base number inStyracaceae is probably x = 8 (2n = 2x = 16) with stabilized triploids inHalesia andPterostyrax (2n = 3x = 24). A preliminary comparison withSapotaceae andEbenaceae does not allow a general karyological characterisation of the orderEbenales.
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  • 63
    Digitale Medien
    Digitale Medien
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    Plant systematics and evolution 177 (1991), S. 161-164 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Oxalidaceae ; Hypseocharis ; Floral anatomy ; systematics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The floral anatomy of threeHypseocharis spp. has been studied. The genus resemblesOxalidaceae as well asMonsonia andSarcocaulon of theGeraniaceae. As it is closer toGeraniaceae than toOxalidaceae, it perhaps serves as a connecting link between them.
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 177 (1991), S. 117-138 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Umbelliferae ; Angelica ; Chromosome numbers ; karyotypes ; karyosystematics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Morphometric karyotype characters were studied in 25Angelica spp. (Umbelliferae, Apioideae) and in one species of the related genusTommasinia. For three species the chromosome numbers are new. In our study the majority of the species investigated are diploids with 2n = 22, some are tetraploids with 2n = 44 (for these tetraploids also diploid cytotypes are reported in the literature). Among the diploid species,A. miqueliana has a distinct karyotype consisting of submetacentric and acrocentric chromosomes only, the remaining diploids with 2n = 22 as well as tetraploids with 2n = 44 have rather symmetrical karyotypes, consisting of metacentric and submetacentric chromosomes. The very different chromosome number 2n = 28 has been found inA. gmelinii. Its karyotype includes two distinct groups of chromosomes: 8 pairs of rather large metacentrics and submetacentrics and 6 pairs of very short and asymmetrical chromosomes. Chromosome numbers and structures appear to be useful in the taxonomy of some intrageneric taxa inAngelica.
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  • 65
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Cyperaceae ; Carex laevigata ; Agmatoploidy ; chromosome fusion ; chromosome fission ; cytogenetic evolution ; Flora of the Iberian Peninsula
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In this paper cytogenetic studies on 64 specimens from 20 Iberian populations ofCarex laevigata (Cyperaceae) are presented. Chromosome behaviour in meiosis suggests that the different chromosome numbers obtained (ranging from 2n = 69 to 2n = 80) were distributed according to an increasing geographic gradient of chromosome fission along the North → South direction. Four relatively stable areas were also delimited according to chromosome numbers displayed by this species, i.e. 2n = c. 72, c. 74, c. 76, and 78. The meiotic behaviour ofCarex ×deserta (C. laevigata ×C. binervis) was also studied.
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  • 66
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    Digitale Medien
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    Plant systematics and evolution 177 (1991), S. 139-148 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Lemnaceae ; Lemna minor ; Allozymic variation ; clonal propagation ; morphometry ; cosmopolitan distribution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Allozymic and morphometric variation was studied in 28 clones ofLemna minor. This variation was compared with the corresponding variation in four clones ofLemna gibba and four clones ofSpirodela polyrrhiza. A high level of allozymic variation was observed among the clones, despite having been grown under uniform laboratory conditions for several years and despite its quasi-exclusive clonal means of propagation. Based on degree of allozymic similarity,Spirodela polyrrhiza was distinguished from the twoLemna species but the latter species were genetically indistinguishable. Allozymic similarity among clones ofLemna minor was not related to morphometric similarity, nor was it related to the degree of geographic separation or climatic similarity of their sites of origin. The results suggest that allozymic variation among these clones ofLemna minor may be largely neutral and not a consequence of differential selection.
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  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 177 (1991), S. 165-174 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Salicaceae ; Populus ; Ribosomal RNA genes ; restriction enzyme maps ; rDNA analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Ribosomal DNA genes fromP. deltoides have been cloned and specific sequences of the 25 S and 18 S rDNA region, labelled by digoxigenin, have been used to determine the rDNA structure ofPopulus tremula, P. fremontii, P. maximowiczii, P. yunnanensis, P. nigra, P. wislizenii, P. alba. The restriction maps of the coding region appeared to be similar among the examined species and with those ofP. deltoides andP. trichocarpa, reported in a previous paper. Inter- and intraspecific variation in rDNA repeat unit length have been revealed after EcoRI digestions. SstI and XbaI restriction sites have been found at different positions in the IGS of some species. The polymorphic fragments generated by SstI digestion allowed the identification of the hybrid origin of some genotypes. The number of rDNA genes in the genome ofP. deltoides has been estimated to be about 2 000 copies. Finally, the usefulness of these studies inPopulus spp. taxonomy and forestry genetics is discussed.
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  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 177 (1991), S. 175-184 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Poaceae ; Zea mays subsp.mays ; Opal phytoliths ; paleoenvironments ; cultivation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Maize (Zea mays L. subsp.mays) has been identified in archaeological contexts by a high proportion of large cross-shaped phytoliths. Given the numerous races of maize, this study was undertaken to determine if differences below the species level could be noted. It was also designed to see if phytoliths differed in various plant parts at various stages of growth. Several races were grown under experimental conditions. No significant differences were found. Furthermore, few phytoliths alleged to be diagnostic of maize were discovered. Systemic studies of maize and analyses of prehistoric cultivation by means of phytoliths seem not to be as promising as some researchers have argued.
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  • 69
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 177 (1991), S. 185-192 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Campanulaceae ; Campanula dichotoma group ; Hybridization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Four supposedly closely related taxa were crossed artificially to test for hybridization barriers. Intra- as well as inter-specific crossings were made. The intra-specific crossings resulted in a high portion of viable hybrids, whereas hybridization barriers were found in all inter-specific combinations except one. The hybrids were non-viable at different levels, viz., (1) no seeds germinated, (2) seeds formed lethal chlorotic seedings, or (3) seeds formed chlorophyllous seedlings which survived the cotyledonary stage, but developed into intermediate forms with low pollen production and/or a strongly reduced pollen viability. Crossings betweenCampanula afra and any of the other three taxa resulted in a non-viable progeny. The crossing capacity amongC. occidentalis, C. kremeri, andC. dichotoma varied. Combinations with large-flowered maternal taxa and small-flowered paternal ones usually failed, whereas a high number of the reciprocal crossings produced hybrids which survived the cotyledonary stage. The hybrid plants varied in pollen viability and pollen production, however. It is concluded that theCampanula dichotoma group should be treated as comprising four distinct species.
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  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 177 (1991), S. 193-211 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Ranunculaceae ; Batrachium ; Ranunculus ; Karyology ; chromosome number ; chromosome morphology ; polyploidy ; Flora of the Aegean islands
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This paper is the first report of an investigation on differentiation and evolutionary pattern inRanunculus subg.Batrachium mainly on the Aegean islands and treats the karyology in the subgenus. The following taxa and chromosome numbers are recorded.R. peltatus subsp.peltatus: 2n = 32, subsp.baudotii: 2n = 32, subsp.saniculifolius: 2n = 16, 32, and 40;R. peltatus s.l.: 2n = 32 and 48;R. penicillatus subsp.pseudofluitans: 2n = 16;R. rionii: 2n = 16;R. sphaerospermus: 2n = 16;R. trichophyllus: 2n = 32, 40, and 48;R. tripartitus: 2n = 48. The karyotypes show certain interspecific differences in chromosome size, in number of chromosome types according to centromere position and in occurrence and position of satellite chromosomes. r-Index and RCL have been calculated.
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 177 (1991), S. 221-234 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Leguminosae ; Papilionoideae ; Vicieae ; Vicia ; Vetch ; chromosome number ; DNA amount ; microdensitometry ; cytotaxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Collected material of rare and newVicia spp. was investigated from a cytotaxonomic point of view. Nineteen species were examined in total. The study includes 14 novel chromosome counts and measurements of DNA amount, as well as a comparison of chromosome morphology between species. The results of the cytological study support to an extent a recent taxonomical revision of subgenusVicia.
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  • 72
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Poaceae ; Phragmites australis ; Weeds ; isozyme variation ; infrared reflectance ; polyploidy ; clones ; Mississippi River delta
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Isozyme variation was investigated in populations ofPhragmites australis (Poaceae) which have recently invaded and taken over marsh habitat of the Mississippi River delta. Infrared aerial photographs in the Garden Island Bay subdelta of the extensiveP. australis populations reveal distinct, clone-like circular patches within a predominant background. Preliminary evidence indicates that the infrared color differences represent distinct morphological types. However, there are no obvious environmental factors that could account for the peculiar patterns.P. australis collections were taken from five separate and distinct “patches” and adjacent “background”. Only two electrophoretic phenotypes were found: one from “patches” and one from the “background”. In comparing the two, 20% of the 40 loci scored are fixed for alternate alleles. These results indicate a clear correspondence of infrared reflectance with electrophoretic phenotype. In addition, the genetic uniformity as evidenced by the discovery of only two electrophoretic phenotypes supports the contention that the recent spread ofP. australis throughout the Mississippi River delta has been primarily, if not exclusively, a result of vegetative propagation.
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 178 (1991), S. 9-25 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Ranunculaceae ; Caltha palustris ; Chloroplast DNA ; chloroplast genes ; phylogeny ; restriction site maps ; sequence divergence
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A restriction site map of the chloroplast genome ofCaltha palustris L. (Ranunculaceae) has been constructed for 13 restriction endonucleases using filter hybridization with cloned tobacco chloroplast DNA fragments. A size of 153.8 kb has been estimated for theCaltha chloroplast genome. Forty-six chloroplast genes and four open reading frames have been mapped using small tobacco chloroplast gene probes. Chloroplast DNA sequence divergence has been estimated for all pairs of five species ofRanunculaceae, Caltha palustris, Ranunculus bulbosus, R. fascicularis, R. recurvatus, andTrollius ledebourii, and ranges between 0.2% and 9.6% for the total genome. Divergence values are much higher in the small and large single copy regions than in the inverted repeat. Phylogenetic relationships between the five species have been hypothesized using chloroplast DNA restriction site mapping. One hundred and six informative restriction site mutations have been detected using eleven restriction endonucleases. Cladistic analyses of the restriction site mutations have been performed using Wagner and Dollo parsimony algorithms, and confidence intervals have been calculated for the resulting monophyletic groups using bootstrapping. It is demonstrated that restriction site comparisons are applicable to theRanunculaceae on intergeneric level, with the exception of groups having extensive genomic rearrangements. Moreover, sequence divergence is low enough at the interspecific level to allow phylogenetic analyses within genera such asRanunculus.
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  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 178 (1991), S. 55-63 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Ranunculaceae ; Helleborus viridis ; H. odorus subsp.laxus ; H. niger ; H. foetidus ; Storage lipid ; fatty acid composition ; life form
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Root and rhizome of fourHelleborus species:H. viridis, H. odorus, H. niger, H. foetidus were examined throughout a two-year period in order to determine the variation of lipid content and fatty acid composition during the ontogenetic cycle. In the deciduous geophytesH. viridis andH. odorus subsp.laxus the lipid content reaches its maximum during the quiescent phase, whereas in the evergreen geophyteH. niger the lipid content is highest during the main growth period. In the chamaephyteH. foetidus lipid content is always very low and it does not show variation throughout the year. In all species the fatty acids detected in the neutral fraction are myristic, palmitic, stearic, oleic and linoleic acid. Palmitic and linoleic acid are always present in larger quantities. The pattern of the relative content of saturated/unsaturated fatty acids seems to be linked to the life form of these species.
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 178 (1991), S. 95-105 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Asclepiadaceae ; Asclepiadeae ; Cynanchinae ; Sarcostemma ; Floral anatomy ; floral morphology ; pollination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Field observations on pollination in New World species of the genusSarcostemma R. Br. sensuHolm are reported. Morphological and anatomical comparisons of pollinated flowers ofSarcostemma subg.Ceramanthus Kuntze (New World) andSarcostemma subg.Sarcostemma (Old World) are presented.
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  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 178 (1991), S. 65-94 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Rubiaceae ; Cinchoneae ; Taxonomy ; phylogeny ; cladistics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Circumscription of the tribeCinchoneae (Rubiaceae) is reconsidered on the basis of a cladistic analysis of structural data comprising 48 characters (164 states). It is concluded that the tribeCinchoneae, in order to be monophyletic, should be restricted to compriseCapirona, Cephalodendron, Cinchona, Cosmibuena, Dolicholobium, Ferdinandusa, Joosia, Ladenbergia, Macrocnemum, andRemijia. It is also suspected, on insufficient evidence, thatMaguireocharis, Pimentelia, andStilpnophyllum belong here.Alseis, Calycophyllum, Schizocalyx, andWittmackanthus form a monophyletic group possibly related to theCinchoneae. A new tribe,Calycophylleae, is proposed to accommodate them.Hillia, which is possibly the sister group of theCinchoneae, is retained in a separate tribe.Coptosapelta, Corynanthe, Crossopteryx, Hymenodictyon, Luculia, Mitragyna, Mussaendopsis, Paracorynanthe, Pausinystalia, andUncaria are referred to the same tribe, for which the nameCoptosapelteae has to be adopted. Probably alsoGreeniopsis belongs here. The generaCigarilla, Coutarea, andExostema, and possiblySyringantha andWernhamia, seem to be most closely related toPortlandia and should be transferred to the tribeCondamineeae. Bouvardia, Coursiana, Danais, Duidiana, Dunnia, Heterophyllaea, Hindsia, Lecanosperma, Manettia, Merumea, Neohymenopogon, andSchismatoclada should be provisionally transferred to the tribeHedyotideae, which is suspected to be polyphyletic, however. No conclusive results were reached concerning the position ofBalmea, Blepharidium, Emmenopterys, andSuberanthus, the position of them remaining uncertain.
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  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 178 (1991), S. 247-258 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Asteraceae ; Crepis tectorum ; Genetic analysis ; geographical variation ; leaf shape
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Canonical variate analysis of plants raised in a uniform environment was used to study the pattern of geographical variation in leaf shape ofCrepis tectorum (Asteraceae). The diversity in leaf shape was much greater among populations confined to areas with exposed bedrock in the Baltic region than among weed populations scattered throughout Europe and Canada. A Ward's clustering linked outcrop populations from the archipelago of SW. Finland and the islands of Öland (Sweden) and Saaremaa (Estonia) due to the deeply lobed leaves characterizing these populations, while outcrop populations along the coast of E. Sweden were grouped due to their weakly lobed, narrow and dentate leaves. Most of the weed populations were grouped together but there was no tendency for the variation in this group to be related to habitat or geographical location. A mosaic of variation reflected in sharp (random) differentiation among local populations was superimposed on the large-scale ecogeographical pattern.—Crossing data indicated that most of the variation in degree of leaf dissection is governed by one major gene with deeply lobed leaves dominant over weakly lobed leaves. I suggest that the simple pattern of inheritance may have favoured rapid evolutionary changes in leaf shape, particularly in the Baltic area which emerged relatively late from the sea. Genetic correlations may have constrained the pattern of variation at higher taxonomic levels, since some of the trait associations detected in a segregating F2 generation were also found at the among-population level.
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 178 (1991), S. 259-269 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Scrophulariaceae ; Paulownia taiwaniana ; P. fortunei ; P. kawakamii ; Isozymes ; morphology ; wood anatomy ; trichomes ; inflorescence grafting ; genetic analyses ; Flora of Taiwan
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Paulownia taiwaniana, the widely cultivated, commercially important tree, has been suspected of being of hybrid origin at least since its original publication in 1975. Evidence in support of this thesis, derived from a number of different investigations, is presented in this paper.—Strong evidence comes from a controlled pollination study of the two supposed parental species,P. kawakamii andP. fortunei. F1 seedlings, derived from reciprocal crosses between the suspected parents, exhibited identical banding patterns for a number of enzymes (such as SKDH, GOT, and IDH) withP. taiwaniana, when separated by electrophoresis. Furthermore, comparative morphological studies of trichomes and wood parenchyma patterns between the purported parents andP. taiwaniana reveal that this latter qualitatively exhibits characteristics that combine features of both of the suspected parental types. Biochemically, eight enzyme systems were compared in the three species here under discussion, and, without exception, the electrophoretic banding patterns exhibited byP. taiwaniana represented a combination of the alleles of the other two species. Perhaps the most convincing evidence comes from a genetic analysis of the progeny obtained by selfingP. taiwaniana. Genotypic segregation of the offspring based on a single locus each of SKDH and PGI fit the 1:2:1 hypothesis. Genotypic segregation of the offspring based on two loci each of SP and GOT fit the ratio of 3:6:3:1:2:1. This, taken in conjunction with the other data presented, clearly suggests thatP. taiwaniana is a hybrid involvingP. kawakamii andP. fortunei.
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  • 79
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Size exclusion chromatography ; Styrene-methacrylate polymers ; IR and UV spectroscopy ; Lubricating oils additives
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Characterization of a poly(styrene-alkyl methacrylate) viscosity index improver according to its chemical composition distribution and molecular weight distribution was carried out by liquid adsorption chromatography, size exclusion chromatography and infrared and ultraviolet spectrophotometry. The industrial polymer was fractionated by liquid chromatography using silica gel as adsorbent and a mixture of 1,2-dichloroethane and methanol as mobile phase. Each fraction was analyzed by size exclusion chromatography and infrared and ultraviolet spectroscopy. The number average molecular weight ranged from 10000 to 36000 and the weight average molecular weight from 19000 to 264000. The styrene content of the various fractions analysed was between 29.5% and 72.2%.
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  • 80
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Laidlomycin, 26-deoxylaidlomycin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary High performance liquid chromatography on an octadecyl silica column has been used to determine laidlomycin: 26-deoxylaidlomycin ratios and to determine the concentration of both compounds by standard addition in samples prepared from fermentation broths ofStreptoverticillium olivoreticuli. A refractive index detector was preferred to an ultraviolet detector owing to the presence of UV-absorbing impurities which could not be completely separated from the substances of interest. Linear relationships were obtained from the calibration data. The coefficient of variation for the estimation of ratio and concentration of the compounds determined was better then 5%. The estimated limit of detection for both substances was about 50μg·ml−1.
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  • 81
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Molecular structure parameters ; Prediction of retention ; Phosphoroamidothiotes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Multi-variable regression analysis between lnkw, c (in retention equation lnk′=lnkw+cCb) and molecular structure parameters, including hydrophobicity, electric effect, field effect and position-specific effect constant, was carried out with O-ethyl, O-aryl and N-isopropyl phosphoroamidothioates as test solutes. With these quantitative relationships, the retention behaviour of these solutes for different mobile phase compositions was predicted. The results showed that there are only 26.7% of total, experimentally measured, capacity factors with relative deviations larger than 5% and only 2.2% with deviations larger than 10%, which means that it is possible to apply the method reported to predict retention values for qualitative purposes for different mobile phase compositions.
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  • 82
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Histamine in wine ; Pre-column derivatization ; Solid phase extraction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A method for determining histamine in wine by precolumn derivatization with PITC (phenylisothiocyanate) with reversed-phase HPLC and UV detection is reported. Histamine can be determined together with the 24 amino acids within 40 min, or separately in a shorter time (less than 4 min) if a prior solid phase extraction clean-up is used.
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  • 83
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Cyclodextrin inclusion complexes ; Structure-retention relationships ; Polycyclic aromatics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The retention behaviour of a group of polycyclic aromatic hydrocarbons having nearly equal ionization potentials but different molecular polarizability values was investigated by reversed-phase HPLC and gas chromatography, using β-cyclodextrin as a selective inclusion reagent. In HPLC, the cyclodextrin was applied as an additive to the ethanolwater binary mobile phase, while in gas chromatography β-cyclodextrin served as the stationary phase coated on an inert support. The relationships between the capacity factors, molecular polarizabilities and the shape parameter of solute molecules is discussed.
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  • 84
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 31 (1991), S. 67-70 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Cortico-steroids ; Drug adulterants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A sensitive and specific method for quantitation of the steroids betamethasone, prednisolone and cortisone acetate commonly used as adulterants in locally produced herb extracts and in certain homeopathic drugs is described. Reverse-phase liquid chromatography with UV detection has been used.
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 31 (1991), S. 80-84 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Ion chromatography ; Poly(vinyl alcohol) gel ; Inorganic anions ; UV detection for IC
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Poly(vinyl alcohol) (PVA) gel shows ionic retention properties for common inorganic anions when an acidic eluent is used. The ionic property of the PVA gel is due to the proton-acceptable nitrogen atoms of the cross-linking agent and the carboxylic residues being comprised in the gel matrix. The extent of the net charge on the gel surface depends on the pH of the eluent. At a pH ranging from 2.3 to 5.3, the PVA gel behaves as a weak anion exchanger with very low ion-exchange capacity. At these conditions four UV-absorbing inorganic anions (bromate, bromide, nitrate, and nitrite) are separated by eluting with aqueous sulfuric acid. Alkyl groups introduced on the gel surface hinder the ionized solute molecules from accessing to the positively charged functional groups on the gel surface. A neutral solute (HNO2) is retained with non-ionic interactions.
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  • 86
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 31 (1991), S. 589-594 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Injection conditions ; Chlorophylls and carotenoids ; Extraction solvents ; Phytoplankton pigments
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The RP-HPLC analysis of chlorophylls, their degradation products (chloropigments) and carotenoids is very sensitive to the nature of the injection solvent. The effect of sample-solvent interaction can result in the production of distorted, or even false, peaks that could be erroneously interpreted as “pigment like” or as poor chromatographic resolution. The previously suggested theoretical explantion, based on differences in solvent characteristics as expressed by the Polarity Index (P′) or even by the more precise solvent strength parameter for reversed-phase systems (S) we use, was unsatisfactory. The problem seems more complex, with other parameters such as injection volume and solute concentration or solvent selectivity also playing a role. As a practical consequence, however, suggesions are made for optimum injection conditions. Also, the presence of ion-pairing reagents in the injection solvent is demonstrated to be unnecessary.
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  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 31 (1991), S. 129-132 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; End-capping ; Chiral stationary phase ; Enantioselectivity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The effect of end-capping chiral stationary phases (CSP's) derived fromN-(2-naphthyl)alanine undecyl ester has been examined using either trimethylchlorosilane (TMCS), hexamethyldisilazane (HMDS), or bis(trimethylsilyl) trifluoroacetamide (BSTFA) as end-capping reagents. The separation factor (α) and capacity factor (k′) of the enantiomers ofN-(3,5-dinitrobenzoyl)leucine octadecyl amide andN-(3,5-dinitrobenzoyl)alanine butyl ester were evaluated on three columns all packed with material from the same batch of stationary phase. These columns were essentially identical before, but not after end-capping with the above reagents. TMCS and HMDS were found to be superior to BSTFA, which appears to cause a significant loss of bonded phase from the silica surface. It seems that residual silanols affect the retention either by interacting with the analyte or by interacting with strands of stationary phase. End-capping usually increases enantioselectivity, sometimes by decreasing k′ for the first enantiomer and increasing k′ for the second enantiomer. The enhancement in enantioselectivity is greatest in relatively nonpolar mobile phases and occurs to a greater extent for phases having incomplete surface coverages.
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  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 31 (1991), S. 147-151 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Liquid crystal bonded phase ; Polycyclic aromatics ; Carvone and pulegone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A chromatographic and thermodynamic study of the compound [4-(allyloxy)benzoyl]-4-methoxyphenyl (ABMP) as a model of a chemically bonded liquid crystal stationary phase for HPLC was undertaken. A number of polycyclic aromatic hydrocarbons (PAHs) and two small solutes, carvone and pulegone, were studied under varying solvent and temperature conditions. Plots of log k′ vs. % organic in the mobile phase were not completely linear in all cases. The van't Hoff plots revealed at least one phase transition. The enthalpies of solute transfer from the mobile phase to the ABMP phase were determined for several PAHs. All tests indicate that ABMP possess liquid crystal properties when bonded to particulate silica.
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  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 31 (1991), S. 193-205 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Column liquid chromatography ; Silanol adsorption centres ; Strongly interacting adsorption sites ; Suppression of adsorption activity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary In this second part of the review heterogeneity of the silica surface is described and evidence is presented for the existence of a low population of strong adsorption sites. Methods of detection and determination of these strongly interacting sites are discussed. The last part of the review is devoted to the suppression of unwanted adsorption activity. Methods of blockage and special methods for the preparation of HPLC packings are described.
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  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 31 (1991), S. 277-280 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Simplex optimization ; Narasin in fermentation broth ; Vanillin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A rapid HPLC assay with post-column derivatization has been developed for the determination of narasin in fermentation broth. The reaction of narasin with substituted benzaldehydes was investigated under first order conditions and the rate constants were determined for a variety of substituted benzaldehydes. Vanillin reacted most rapidly to produce a red color. The reaction conditions were optimized to acheive a maximum response with a minimum analysis time.
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  • 91
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Ovomucoid stationary phase ; Chiral separations ; Mobile phase effects ; Protein conformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The effects of alcoholic modifiers and pH on the chromatographic properties of an immobilized ovomucoid chiral stationary phase have been investigated using acidic, basic and neutral solutes. A series of primary, secondary and tertiary alcohols and pH's ranging from 3.5 to 6.0 were used in this study. The results indicate that both the shape and the hydrophobicity of the alcoholic modifier affect retention (k') and enantioselectivity (α). In general, an increase in the hydrophobicity of the modifier results in a decrease in k's and α's. However, this is not the case whent-butanol is the modifier, suggesting that the size of the alkyl moiety attached to the carbinol carbon also contributes to the chromatographic results. The pH studies indicated that Coulombic interactions play a role in the retention of the acidic and basic solutes. The results also suggest that in addition to ethanol and 1-propanol,t-butanol should be considered during optimization and that maximum efficiencies may be obtained at pH 5.0.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 92
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Adsorption isotherms ; Immobilized serum albumen ; Chiral stationary phase ; Leucine, N-benzoyl derivative
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The saturation capacity of columns packed with bovine serum albumin immobilized on silica has been determined for the N-benzoyl derivative of leucine at different compositions of a 1-propanol/water mobile phase. In all cases it has been found that the equilibrium adsorption data are well accounted for by a biLangmuir isotherm. The experimental data are consistent with the assumption that the column saturation capacity of the chiral selective sites as well as the saturation capacity of the non-selective sites are independent of the 1-propanol concentration in the range 0–10%.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 93
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Bonded phase synthesis ; Alkyl and aryldimethyl phases ; CP/MAS NMR spectroscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A comparison of newly synthesized, reversed-phase bonded stationary phases is presented. The materials studied include monomeric n-octyl, n-octadecyl, aryl and n-octyldihydrogeno bonded-phases. Differences in reactivity of the silane functional groups are demonstrated and the high coverage obtained with the hydrogeno-bonded phases is shown. The structures of the bonded phases have been determined by29Si and13C CP/MAS NMR spectroscopy.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 31 (1991), S. 347-350 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Chemically modified silicas ; Surface states ; n-alkylbenzenes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The thermodynamic behaviour of n-alkylbenzenes on chemically modified silicas in reversed-phase liquid chromatography has been examined in acetonitrile-water and methanol-water systems. Plots of the thermodynamic parameters obtained against the organic solvent compositions indicate an interesting trend which implies that the surface states of the chemically modified silicas under the two eluent systems are different.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 31 (1991), S. 362-366 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Particle size distribution ; Stationary phase stress ; Silica gel
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A particle size distribution analysis has been completed on three different HPLC column packing materials including silica gel (Si60) and two bonded phases (RP8 and RP18). The stationary phases were subjected to 18 hours stress with 1 N or 3 N KOH and found to have quantitatively different distribution patterns initially, at 13 hours and finally at 18 hours although the average particle diameters for the Si60 and RP8 were the same or higher at 18 hours as initially. Thirteen hoursstress with sodium octanesulfonate, tetrabutylammonium phosphate and ammonium acetate at exaggerated conditions also resulted in distributional changes with the Si60 and RP8 decreasing in average particle diameter when exposed to ammonium acetate and tetrabutylammonium stressing respectively.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 96
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Biogenic amines ; Wine ; Food-related biogenic amines
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Methods for the separation of food-related biogenic amines (histamine, tyramine, 2-phenylethylamine and tryptamine) have been developed based on ion-interaction reversed-phase liquid chromatography. Two different interaction reagents have been comparatively used, namely octylamine ortho-phosphate (at wave-lengths of 230, 254 and 280 nm) and octylamine salicylate (at a wavelength of 254 nm). The different elution sequence orders shown by the investigated amines for the two reagents are discussed and compared. The detection limits obtained were 20 ppb for tryptamine (λ =280 nm), 500 ppb for 2-phenylethylamine (λ=254 nm), 400 ppb for tyramine (λ=230 or 280 nm) and 900 ppb for histamine (λ=230 nm). The method was applied to the analysis of a five years old Italian red wine, in which 2-phenylethylamine (at a concentration of 72±3 ppm) and tryptamine (at a concentration of 4.0±0.3 ppm) were found to be present.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 31 (1991), S. 387-392 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Retention model ; Self-association of water
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary An attempt has been made to gain a semi-quantitative insight into the self-association of water molecules through hydrogen bonds. This was only possible with the use of a new solute retention model for the chromatographic systems by considering intermolecular interactions between the constituents of binary mobile phases. Four different sizes of the average associative aqueous multimer were assumed. By comparing measured and calculated retention values, the existence of associated aqueous multimers consisting of 100 aqueous monomer units is postulated as an average multimer structure.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 31 (1991), S. 401-410 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Ion-pair reversed-phase separations ; Nucleotides ; Extraction from cells and tissue ; Retention mechanism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary HPLC methods for the separation of nucleotides, nucleosides and nucleobases by ion-pair reversed-phase are reviewed. The advantages of these are discussed versus anion-exchange and reversed phase separations. Extraction procedures for nucleotide determinations from cells and tissues are pointed out in detail. Extracts from red blood cells, Ehrlich ascites tumour cells, hepatocytes, intestine are used for determination of nucleotide concentrations by the methods described.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Ion exchange chromatography ; Quantitative amino acid analysis ; OPA/FMOC precolumn derivatization ; Cheese
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary An improved HPLC method for the quantitative determination of the amino acids from hydrolysed cheese proteins and peptides is described. Some important improvements to the existing method are suggested. The addition of piperidine-4-carboxylic acid (PICA) as a hydrolysis-resistant internal standard enabled the quantification of secondary amino acids. The following analytical parameters have been determined: repeatability, detection limit and linearity in the measuring range. A statistical comparison with the classical ion chromatographic method gave an excellent correlation for all determined amino acids. Both methods are free of artifacts and systematic errors. Compared with ion chromatography, HPLC shows the following advantages: faster equilibration of the column, shorter retention times, more stable baseline, narrower peaks and more sensitive fluorescence detection. A drawback is the slightly lower repeatability for some amino acids.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 31 (1991), S. 429-433 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Chiral separations ; Amino acids ; Fluorogenic derivatization ; N-(Chloroformyl)-carbazole
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A new reagent for fluorescence labelling of amino acids, N-(chloroformyl)-carbazole, has been used in order to achieve high sensitivity of detection as well as good optical resolution. The derivatization reaction is fast and conveniently carried out at room temperature by shaking a buffered aqueous solution of the amino acids with an acetone solution of the reagent. The individual derivatized amino acids are first separated and collected via chromatography on a standard octadecyl-silica column. Each amino acid derivative is then analyzed for enantiomer composition by re-injection on a BSA-silica (Resolvosil®) column using fluorescence detection. For some amino acids (alanine, threonine, phenylalanine, tryptophan) enantiomeric separation factors exceeding α=3 have been obtained. The phosphonic acid analogue of alanine (1-aminoethylphosphonic acid) was also found to be well resolved into its enantiomers.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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