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  • Angiosperms  (306)
  • Saccharomyces cerevisiae  (169)
  • Springer  (475)
  • 2005-2009
  • 1985-1989  (475)
  • 1950-1954
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of industrial microbiology and biotechnology 4 (1989), S. 49-53 
    ISSN: 1476-5535
    Keywords: l-Phenylacetyl carbinol ; Saccharomyces cerevisiae ; Yeast ; Benzaldehyde ; Biotransformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary The rate of production ofl-phenylacetyl carbinol bySaccharomyces cerevisiae in reaction mixtures containing benzaldehyde with sucrose or pyruvate as cosubstrate was investigated in short 1 h incubations. The effect of yeast dose rate, sucrose and benzaldehyde concentration and pH on the rate of reaction was determined. Maximum biotransformation rates were obtained with concentrations of benzaldehyde, sucrose and yeast of 6 g, 40 g and 60 g/l, respectively. Negligible biotransformation rates were observed at a concentration of 8 g/l benzaldehyde. The reaction had a pH optimum of 4.0–4.5. Rates of bioconversion of benzaldehyde and selected substituted aromatic aldehydes using both sucrose and sodium pyruvate as cosubstrate were compared. The rate of aromatic alcohol production was much higher when sucrose was used rather than pyruvate.o-Tolualdehyde and 1-chlorobenzaldehyde were poor substrates for aromatic carbinol formation although the latter produced significant aromatic alcohol in sucrose-containing media. Yields of 2.74 and 3.80 g/l phenylacetyl carbinol were produced from sucrose and pyruvate, respectively, in a 1 h reaction period.
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  • 2
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    Journal of industrial microbiology and biotechnology 4 (1989), S. 81-84 
    ISSN: 1476-5535
    Keywords: Ethanol fermentation ; Wheat starch ; Saccharomyces cerevisiae ; immobilization ; Continuous dynamic immobilized biocatalyst bioreactor ; Biocatalyst bioreactor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary A simple and efficient method of conversion of wheat starch B to ethanol was investigated. Employing a two-stage enzymatic saccharification process, 95% of the wheat starch was converted to fermentable sugars in 40 h. From 140 g/l total sugars in the feed solution, 63.6 g/l ethanol was produced continuously with a residence time of 3.3 h in a continuous dynamic immobilized biocatalyst bioreactor by immobilized cells ofSaccharomyces cerevisiae. The advantages and the application of this bioreactor to continuous alcoholic fermentation of industrial substrates are presented.
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  • 3
    ISSN: 1572-8773
    Keywords: Manganese ; Electron spin resonance ; Superoxide dismutase ; Saccharomyces cerevisiae ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Manganese accumulation was studied by room-temperature electron spin resonance (ESR) spectroscopy inSaccharomyces cerevisiae grown in the presence of increasing amounts of MnSO4. Mn2+ retention was nearly linear in intact cells for fractions related to both low-molecular-mass and macromolecular complexes (‘free’ and ‘bound’ Mn2+, respectively). A deviation from linearity was observed in cell extracts between the control value and 0.1 mM Mn2+, indicating more efficient accumulation at low Mn2+ concentrations. The difference in slopes between the two straight lines describing Mn2+ retention at concentrations lower and higher than 0.1 mM, respectively, was quite large for the free Mn2+ fraction. Furthermore it was unaffected by subsequent dialyses of the extracts, showing stable retention in the form of low-molecular-mass complexes. In contrast, the slope of the line describing retention of ‘bound’ Mn2+ at concentrations higher than 0.1 mM became less steep after subsequent dialyses of the cell extracts. This result indicates that the macromolecule-bound Mn2+ was essentially associated with particulate structures. In contrast to Cu2+, Mn2+ had no effect on the major enzyme activities involved in oxygen metabolism except for a slight increase of cyanide-resistant Mn-superoxide dismutase activity, due to dialyzable Mn2+ complexes.
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  • 4
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Vector ; Glyphosate resistance ; Transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The E. coli aroA gene was inserted between yeast promoter and terminator sequences in different shuttle expression plasmids and found to confer enhanced EPSP synthase activity as well as resistance to glyphosate toxicity. Subsequently, a transformation system using these newly constructed vectors in yeast was characterized. The efficiency of the glyphosate resistance marker for transformation and selection with plasmid pHR6/20-1 in S. cerevisiae laboratory strain SHY2 was found to be relatively high when compared with selection for LEU2 prototrophy. The fate of the recombinant plasmid pHR6/20-1 in the transformants, the preservation of the aroA E. coli DNA fragment in yeast, mitotic stability, EPSP synthase activity, and growth on glyphosate-containing medium have been investigated. As this plasmid also allows direct selection for glyphosate resistant transformants on rich media, the glyphosate resistance marker was used for transforming both S. cerevisiae laboratory strain SHY2 and brewer's yeast strains S. cerevisiae var. “uvarum” BHS5 and BHS2. In all cases, the vector pHR6/20-1 was maintained as an autonomously replicating plasmid. The resistance marker is, therefore, suitable for transforming genetically unlabeled S. cerevisiae laboratory, wild, and industrial yeast strains.
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  • 5
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Chromosome V ; Ty elements ; tRNA genes ; Transposition hot-spots ; Yeast polymorphism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ty4 is a novel transposable element in the yeast, Saccharomyces cerevisiae, which is present in only a few copies in the genome (Stucka et al. 1989). In strain C836 one of the three copies (Ty4-90) is contained in cosmid clone c90, where it resides on chromosome V. Analysis of this region reveals a “hot-spot” of transposition: in addition to Ty4-90, the locus contains a complete Ty3 element and seven singular delta, sigma and tau elements. Three tRNA genes (for His, Lys, and Ile) are located in this region, and these are closely associated with one or the other of the elements, a phenomenon commonly observed in yeast. A comparison of c90 with corresponding regions from other strains shows that the locus is highly polymorphic and that this polymorphism is explicitly associated with Ty transposition and recombination events.
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  • 6
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    Current genetics 16 (1989), S. 315-321 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Antisuppressor ; ADE3 ; Translation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mutations in a known yeast gene, ADE3, were shown to act as an antisuppressor, reducing the efficiency of the omnipotent suppressor, sup45-2. The ADE3 locus encodes the trifunctional enzyme C1-tetrahydrofolate synthase, which is required for the biosynthesis of purines, thymidylate, methionine, histidine, pantothenic acid and formylmethionyl-tRNAfmet. The role of this enzyme in translational fidelity had not previously been suspected.
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  • 7
    ISSN: 1432-0983
    Keywords: Yeast ; Saccharomyces cerevisiae ; Nonsense suppression ; Omnipotent suppressors ; Gene mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ten dominant omnipotent suppressors of Saccharomyces cerevisiae, which were previously shown to be different from SUP46, have been examined. Nine are mapped in a region between lys5 and cyh2 on the left arm of chromosome VII. These suppressors, like SUP46, manifest sensitivity to increased temperature and the antibiotics paromomycin and hygromycin B. In addition, they have an identical action spectrum. These results strongly suggest that they are allelic to each other and they are designated SUP138. The tenth is mapped to a position between his1 and arg6 on the right arm of chromosome V. This suppressor, named SUP139, does not manifest temperature sensitivity nor antibiotic sensitivity. SUP139 and SUP138, which are clearly distinguished by means of action spectrum, act on much fewer nonsense mutations than SUP46. It is now clear that dominant omnipotent suppressors arising at a single locus are homogeneous and that their efficiency is locus-dependent. The order of efficiency is SUP46〉SUP138〉SUP139.
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  • 8
    ISSN: 1432-0983
    Keywords: Yeast ; Repair ; Complementation ; Saccharomyces cerevisiae ; Schizosaccharomyces pombe ; Gene cloning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two Saccharomyces cerevisiae genes necessary for excision repair of UV damage in DNA, RAD1 and RAD2, were introduced individually, on a yeast shuttle vector, into seven Schizosaccharomyces pombe mutants — rads1, 2, 5, 13, 15,16 and 17. The presence of the cloned RAD1 gene did not affect survival of any of the S. pombe mutants. The RAD2 gene increased survival of S. pombe rad13 to near the wild-type level after UV irradiation and had no effect on any of the other mutants tested. S. pombe rad13 mutants are somewhat defective in removal of pyrimidine dimers so complementation by the S. cerevisiae RAD2 gene suggests that the genes may code for equivalent proteins in the two yeasts.
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  • 9
    ISSN: 1432-0983
    Keywords: DNA transformation ; Saccharomyces cerevisiae ; Site-specific recombination ; 2μ DNA plasmid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The 2μ DNA plasmid of the yeast Saccharomyces cerevisiae does not confer any known selectable phenotype to the host cell carrying it. Selection of cells transformed with purified 2μ DNA therefore cannot be achieved, and the intracellular presence of 2μ can only be assessed by molecular analysis of the DNA complement. In addition, 2μ alone does not replicate in bacterial hosts, thus rendering its amplification by conventional methods impossible. We have isolated a shuttle plasmid, pBH-2L, generated by in vivo sites-pecific recombination between the endogenous 2μ DNA plasmid and pRL, a pBR322 derivative containing the yeast LEU2 gene and one 2μ repeat sequence associated with the origin of replication. This new shuttle plasmid has the property, when transformed into yeast, of undergoing site-specific recombinational resolution between its two direct repeat sequences. This releases 2μ plasmid and pRL as individual molecules. The latter can undergo progressive mitotic loss during growth in nonselective medium, ultimately leaving leucine auxotrophic transformants that contain only 2μ DNA plasmid. This system can be utilized to introduce 2μ DNA alone into cells lacking it, thereby providing a novel means to study the biology and the molecular genetics of the plasmid and its potential practical applications as a vector.
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  • 10
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    Current genetics 15 (1989), S. 113-120 
    ISSN: 1432-0983
    Keywords: Calmodulin mutant ; Nuclear division ; Chromosome stability ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The coding region of a yeast calmodulin gene was fused to a galactose-inducible GAL1 promoter, and a conditional-lethal mutant of Saccharomyces cerevisiae, in which the expression of calmodulin was regulated by galactose, was constructed. The mutant grew normally in galactose medium, but in glucose medium, in which the promoter was repressed, it ceased growing after 12–15 h. The growth arrest was associated with a decrease in intracellular calmodulin levels: after 12h, no intracellular calmodulin protein was detectable. Analysis of the terminal phenotype showed that when the cell stopped growing, it had a bud, a nucleus after S-phase and a short mitotic spindle. Thus, the defect was mainly in nuclear division. Bud growth was partially inhibited in these cells: 27% of the cells stopped growing with a small bud. Furthermore, calmodulin-deficient cells showed elevated rates of chromosome loss, possibly as the result of a defect in the precise segregation of chromosomes.
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  • 11
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    Current genetics 15 (1989), S. 235-237 
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Mitochondrial DNA ; Method of extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A rapid method for the extraction of yeast mitochondrial DNA (mtDNA) is described. In comparison with previous methods, it simplifies several steps, does not require either the isolation of mitochondria or phenol treatment and is less time consuming. This protocol gives a high yield of pure mtDNA (50–120 μg from a 100-ml culture), which can be directly used in various molecular applications: restriction enzyme digestion, electrophoresis, blotting, labeling, cloning and sequencing.
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  • 12
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Mutagen hyperresistance ; Southern, Northern analysis ; Gene transplacement ; Transposon mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The genes SNQ and SFA confer hyperresistance to 4-NQO and FA when present on a multi-copy plasmid in yeast. Both are non-essential genes since transplacement of SNQ by a disrupted snq-0::LEU2 yielded stable and viable haploid integrants. Southern analysis revealed that SNQ and SFA are single-loci genes, and OFAGE analysis showed that they are located on chromosome XIII and IV, respectively. Northern blot analysis of SNQ and SFA revealed poly(A)+ RNA transcripts of 2 kb and 1.7 kb, respectively. Nuclease S 1 mapping showed SNQ to have a coding region of 1.6 kb and SFA, one of 1.3 kb. The 5′ coding regions were determined for both genes, while the 3′ end could only be determined for gene SNQ. Both genes do not appear to contain introns. The SFA locus was also mapped by transposon mutagenesis. Tn10-LUK integrants disrupted the SFA gene function at sites that were determined by subcloning to lie within the SFA transcription unit.
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  • 13
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; SKI3 ; SKI5 ; M1 dsRNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have identified a mutant strain of the yeast Saccharomyces cerevisiae which overproduces killer toxin. This strain contains a single mutation which fails to complement defects in both the SKI3 and SKI5 genes, while a cloned copy of this gene complements both the ski3 and ski5 defects. The level of secreted toxin from a cDNA based plasmid is not increased in a ski3 strain, showing that the overproduction phenotype is dependent upon an increased level of M1 dsRNA.
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  • 14
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Psoralen photoaddition ; Interstrand cross-link ; Repair deficiency ; Genotoxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two different UVA irradiation systems were initially biologically calibrated with two haploid yeast strains proficient and deficient, respectively, in nucleotide excision repair. The number of DNA lesions introduced into the cell's genome by the photoactivated bifunctional furocoumarin 8-MOP was then calculated by means of the applied UVA exposure doses. At LD37 the repair-proficient wild type had about 14 ICL and 34 furan-side monoadducts in its DNA, while doubly blocked repair mutant rad3-12 pso1-1 had 2 ICL and 3 monoadducts. Locus-specific reversion of lys1-1 followed two-hit kinetics in the repair-proficient wild type and one-hit kinetics in an excision-deficient rad2-20 mutant, as would be expected if ICL was the main type of mutagenic lesion in the wild type and monoadducts the main mutagenic lesion type in the excision-deficient strain. Quantitative comparison of 8-MOP + UVA-induced ICL with those induced by bifunctional mustard revealed the former to have a much higher genotoxicity.
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  • 15
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Protoplast fusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The percentage of hybrids formed during protoplast fusion in Saccharomyces cerevisiae is determined by the percentage of protoplasts at the GI/S boundary of the cell cycle.
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  • 16
    ISSN: 1432-0983
    Keywords: Peroxisomes ; Protein import ; Saccharomyces cerevisiae ; Hansenula polymorpha
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The DAS gene of Hansenula polymorpha was expressed in Saccharomyces cerevisiae under the control of different promoters. The heterologously synthesized dihydroxyacetone synthase (DHAS), a peroxisomal enzyme in H. polymorpha, shows enzymatic activity in baker's yeast. The enzyme was imported into the peroxisomes of S. cerevisiae not only under the appropriate physiological conditions for peroxisome proliferation (oleic acid media), but also in glucose-grown cells where it induced the enlargement of the few peroxisomes present. This growth process was not accompanied by an increase in the number of microbodies, which suggests a separate control mechanism for peroxisomal proliferation.
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  • 17
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    Current genetics 15 (1989), S. 399-401 
    ISSN: 1432-0983
    Keywords: Saccharomyces exiguus ; Saccharomyces cerevisiae ; HO gene ; MAT gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The DNA of Saccharomyces exiguus was analyzed by Southern hybridization using cloned MATa, MATα, and HO genes of Saccharomyces cerevisiae as probes. It was shown that S. exiguus has a DNA sequence homologous with the HO gene of S. cerevisiae and that this DNA sequence is on a chromosome of about 940 kb of DNA in S. exiguus. However, there is no DNA sequence in S. exiguus that is homologous with the MAT genes of S. cerevisiae.
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  • 18
    ISSN: 1420-9071
    Keywords: Saccharomyces cerevisiae ; growth conditions ; kinaseless mutant ; plasma membrane vesicles ; glucose transport ; kinetics and computer simulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In this study experimental data on the kinetic parameters investigated by other authors1–5, 11 together with own data on plasma membrane vesicles, have been subjected to a computer simulation based on the equations describing facilitated diffusion. The simulation led to an ideal fit describing the above data. From this it can be concluded that glucose is transported by facilitated diffusion, and not by active transport as was postulated by Van Steveninck14, 15. The simulation method also demonstrates that the fast sampling technique used by these authors1–5,11 underestimates the fluxes. Thus, the parameters given do not contribute to the understanding of glucose transport under different metabolic conditions. The K value of plasma membrane vesicles prepared from glucose-repressed cells is around 7 mM. Derepression, particularly by galactose, causes a highly significant increase in affinity as shown by a decrease in the K value to 2 mM. The highest affinity was measured in a triple kinaseless mutant grown on glycerol with a K value of 1 mM. If seems, therefore, that the kinetic parameters derived from initial uptake rates of glucose in intact cells1–5,11 using single flux analysis, such as Eadie-Hofstee- or Lineweaver-Burk-plots, are in error.
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  • 19
    ISSN: 1432-072X
    Keywords: Saccharomyces cerevisiae ; Yeast ; Phospholipase B ; Lysophospholipase ; Enzyme inhibition ; AMP ; Unesterified fatty acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Divalent cations activate the lysophospholipase and transacylase reactions catalyzed by the same enzymes in the yeast Saccharomyces cerevisiae. The activation was observed at neutral pH, but not at the pH optimum of lysophospholipase/transacylase, near 3.5. Adenine nucleotides, especially AMP and ADP, are strong inhibitors of the same group of enzymes. Half maximal inhibition by AMP was found at a concentration of about 20 μM. The inhibition by nucleotides in low concentrations is enhanced by divalent cations.
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  • 20
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    Archives of microbiology 151 (1989), S. 198-202 
    ISSN: 1432-072X
    Keywords: Sexual agglutination ; Mating ; Saccharomyces cerevisiae ; Yeast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genetic regulation of the inducibility of sexual agglutination ability in the yeast Saccharomyces cerevisiae was studied. Detailed analysis of the degree of sexual agglutination was carried out; it showed that a greater number of genes are involved in the regulation of inducible sexual agglutination in strain H1-0 than previously assumed. Although dominancy of inducible phenotype over constitutive was confirmed, the effectiveness of one gene changing the constitutive phenotype to the inducible seemed to be somewhat low. Quantity per cell of agglutination substances responsible for sexual agglutination increased as the agglutination ability became greater.
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  • 21
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    Archives of microbiology 151 (1989), S. 391-398 
    ISSN: 1432-072X
    Keywords: Saccharomyces cerevisiae ; Exoglucanases ; Purification ; Protein moieties ; Tunicamycin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Exoglucanase (exo-1,3-β-D-glucan glycohydrolase, EC 3.2.1.56) activity secreted by Saccharomyces cerevisiae into the culture medium was separated by ion exchange chromatography into two glycoprotein isoenzymes which contributed 10% (exoglucanase I) and 90% (exoglucanase II) towards the total activity. Analysis of the “in vitro” deglycosylated products by polyacrylamide gel electrophoresis under native or denaturing conditions indicated that the protein portions of both exoglucanases exhibited identical mobility, each one consisting of two polypeptides with M r of 47000 and 48000. The same profile was shown by the exoglucanase secreted in the presence of tunicamycin. Antibodies raised against the protein portion of exoglucanase II did react with both native exoglucanases and their deglycosylated products with a pattern indicative of immunological identity. Digestion of the “in vitro” deglycosylated products of both exoglucanases with Staphylococcus aureus V-8 protease or trypsin generated the same proteolytic fragments in each case. Only exoglucanase II was secreted by protoplasts. These and previously reported results indicate that the protein portions of both isoenzymes may be the product of the same gene (or a family of related genes), and that exoglucanase I is a product of enzyme II, modified by a process occurring beyond the permeability barrier of the cell.
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  • 22
    ISSN: 1432-072X
    Keywords: Saccharomyces cerevisiae ; Recombination ; Tryptophan cluster ; Yeast vectors ; Plasmid copy number
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We describe a convenient method for the in vivo construction of large plasmids that possess a multitude of restriction sites. A large (23 kbases) circular self-replicating plasmid carrying a partial LEU2-d gene was cotransformed with a circular non-replicating plasmid carrying the entire LEU2 gene. In vivo recombination results preferentially in a plasmid that carries both the LEU2-d and the entire LEU2 gene. In addition we also found one plasmid with a tandem LEU2 insertion and one plasmid where the LEU2-d gene was replaced by the entire LEU2 gene.
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  • 23
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    Plant systematics and evolution 162 (1989), S. 213-229 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Fagaceae ; Cuticles ; Recent ; Tertiary ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A systematic reassessment of megafossil records ofFagaceae in Central Europe has been undertaken on the basis of leaf cuticular characters. The oldest representatives date back to the Eocene:Quercus subhercynica spec. nova,Dryophyllum furcinerve (Rossm.)Schmalh.,Trigonobalanopsis rhamnoides (Rossm.) gen. & comb. nov. In the Oligocene other members of extant genera appear:Quercus rhenana (Weyl. & Kilpp.)Knobloch & Kvaček,Fagus attenuata Goepp.,Lithocarpus saxonicus spec. nova. In the Neogene these ancient taxa (except inFagus lineage), are gradually replaced by deciduous species ofQuercus andCastanea. Trigonobalanus andCastanopsis are recorded by fruits (or wood) only.
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  • 24
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    Plant systematics and evolution 162 (1989), S. 165-191 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Chloranthaceae ; Platanaceae ; Trochodendrales ; Fagaceae ; Cercidiphyllum ; Paleobotany ; phylogeny ; floral structure ; leaf architecture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Paleobotanical studies indicate that several isolated and systematically depauperate groups of extant woody dicotyledons originated in the Mid Cretaceous. TheChloranthaceae had probably differentiated into insect-pollinated (Chloranthus andSarcandra) and wind-pollinated (Ascarina andHedyosmum) forms by the end of the Albian, and leaves referable to theTrochodendrales are known from the Albian and Cenomanian. In the latest Cretaceous and Early Tertiary, extinct representatives of theTrochodendrales includedNordenskioldia and theJoffrea-Nyssidium complex. ThePlatanaceae also differentiated before the end of the Albian and initially had insect-pollinated, unisexual flowers with five carpels or stamens. Some of these features persisted in the platanoid lineage until the Early Tertiary, and during the Paleocene and Eocene thePlatanaceae included forms with elliptical, palmate and pinnate foliage. The history of thePlatanaceae suggests that several features of the reproductive morphology of extant taxa may have arisen in association with a trend toward wind pollination. In the Mid Cretaceous, platanoid foliage partially intergrades with pinnateSapindopsis and pedateDebeya-Dewalquea leaves suggesting a close relationship betweenPlatanaceae andRosidae andFagaceae respectively. TheChloranthaceae, Trochodendrales, andPlatanaceae all occupy a somewhat intermediate position between theMagnoliidae andHamamelidae and are of considerable interest with respect to their role in the initial radiation of nonmagnoliid (“higher”) dicotyledons.
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  • 25
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    Plant systematics and evolution 162 (1989), S. 193-211 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Hamamelididae ; Trochodendrales ; Hamamelidales ; Hamamelidaceae ; Hamamelideae ; fossilHamamelidaceae ; Floral structure ; fruit ; seed ; valvate anther dehiscence ; Floral evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract New investigations on the flower and fruit structure of extantHamamelidaceae and other LowerHamamelididae together with new finds of fossil flowers and seeds from the Upper and Lower Cretaceous provide the outline of an increasingly more differentiated picture of the early evolution of the subclass. Three patterns of valvate anther dehiscence are recognized in the subfamilyHamamelidoideae (and the subclassHamamelididae). The basic (plesiomorphic) type within theHamamelididae has 2 valves per theca. The type with 1 valve but 2 pollen sacs per theca is both consistent and exclusive for the 5 southern genera of theHamamelidaceae. They seem to be the remnants of a homogeneous group that originated before the Upper Cretaceous. This is supported by fossil hamamelidaceous flowers from the Upper Cretaceous that have thecae with 1 valve. Since several-seededHamamelidaceae predate one-seeded forms in the fossil seed record (in Europe) and the systematic structure of the one-seeded group is relatively more homogeneous, several-seeded groups are considered to be more ancient. Several parallel evolutionary trends are recognized within theHamamelidaceae as well as within the LowerHamamelididae: anther dehiscence with 2 valves per theca → 1 slit or 1 valve; pollen sacs per theca 2 → 1; pollen tricolpate → polyforate; exine coarsely reticulate → finely reticulate; loss of perianth (tepals or petals and sepals) and concomitant loss of fixed number of floral organs; differentiation of exposed nectaries.
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  • 26
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    Plant systematics and evolution 162 (1989), S. 231-250 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Juglandaceae ; Paleobotany ; pollen ; fruits ; evolution ; Cretaceous ; Tertiary
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The major radiation of theJuglandaceae occurred during the early Tertiary as recorded by the proliferation of juglandaceous pollen and the appearance of fruits representing extinct and extant genera of the family. Juglandaceous pollen types of the Paleocene were predominantly triporate and exhibited a greater diversity in patterns of exinous thinning than occurs in the family today. Analyses of in situ pollen from early Tertiary juglandaceous inflorescences confirms the taxonomic value of certain patterns of exinous thinning. Data from co-occurring fruits and pollen indicate that relatively unspecialized, isopolar triporate pollen of the type presently confined to the tribeEngelhardieae also occurred in other tribes of the family during the Paleocene. Pollination has been mostly anemophilous throughout the Tertiary. Both wind and animal fruit-dispersal syndromes were established early in the radiation of the family but a greater diversity of wind-dispersed genera has prevailed.
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  • 27
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    Plant systematics and evolution 162 (1989), S. 251-265 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Rutaceae ; Phylogeny ; fructifications ; morphology ; anatomy ; paleogeography ; Cretaceous ; Tertiary
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A comparative analysis of the seed morphology and anatomy of fossil and extantRutaceae (mainlyZanthoxyleae andToddalioideae) is presented. This allows to place the most important fossil taxa in a time-table and on paleogeographical maps. A phylogenetic scheme demonstrates the postulated historical relationships ofEvodia, Zanthoxylum, Fagara, Rutaspermum, Acronychia, Toddalia, Fagaropsis, andPhellodendron.
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    Plant systematics and evolution 162 (1989), S. 267-283 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Buxaceae ; Buxus ; Pollen morphology ; leaf venation ; fossil records ; systematics ; evolution ; chorogenesis
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    Notes: Abstract Trends of pollen grain aperture evolution and exine characters as well as characters of leaf venation, petiole and axial vascularization are briefly described and related to geographical distribution and classification ofBuxus. A review of fossil records is given. Three major taxonomic groups can be delimitated within the genus, and aspects of their relationships and chorogenesis are presented. The level of differentiation, the pattern of distribution and the fossil record speak in favour of an ancient origin of the genus.
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    Plant systematics and evolution 165 (1989), S. 227-237 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Eucalyptus ; Eudesmieae ; Floral morphology ; calyx ; corolla ; operculum ; growth ; allometry ; convergence
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    Notes: Abstract In theEudesmieae B eucalypts and inEucalyptus caesia, the perianth of the mature flower consists of a single, anatomically continuous, opercular structure that is crowned by the tips of the original free and separate calycine and corolline whorls. Ontogenetic and comparative evidence supports the hypothesis that this operculum is mostly corolline in composition, and that the calycine parts have been elevated distally onto the dorsal surface. In theEudesmieae B eucalypts this condition appears to be due to precocious initiation of the corolline primordia, followed by expansion and continuity of their growth centres which incorporates the areas at or below the base of the still differentiating calycine whorl. InEucalyptus caesia the corolline primordia are not precocious, but a similar situation is effected by a seemingly retarded increase in receptacle diameter relative to lateral expansion of the corolline growth centre(s). In these two examples the same final perianth form apparently derives from two different sets of growth processes which, nonetheless, result in the same allometric relationships within the developing flower. Although identical at maturity, the operculum form in these two taxa is best described in terms of convergence, rather than homology.
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    Plant systematics and evolution 166 (1989), S. 41-44 
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    Keywords: Angiosperms ; Araceae ; Arum spp. ; Pollen types ; pollination
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    Notes: Abstract In a second paper onArum pollen seven further taxa are investigated. Most of them have spinose pollen, only inA. korolkowii the pollen is scabrose. The possible relation between pollen sculpturing and the actual pollination mode is discussed.
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    Plant systematics and evolution 166 (1989), S. 11-30 
    ISSN: 1615-6110
    Keywords: Angiosperms ; monocotyledons ; Amaryllidaceae ; Eucharis ; Phenetics ; chromosome morphology ; isozyme electrophoresis ; speciation ; sibling species
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    Notes: Abstract Eucharis candida andE. formosa are two often sympatric species of bulbous geophytes restricted to neotropical rain forest understory. The species are most common in eastern Ecuador, and are the only two east Ecuadorean species of the genus found north of the Pastaza valley. Data from phenetic, karyotypic, and preliminary isozyme electrophoretic analyses of both species are represented. The species are distinguishable phenetically and karyologically, but isozyme-based relationships are more complex. Phenetic resolution of the isozyme phenotypes supports recognition of two species in Ecuador. A Peruvian isolate ofE. formosa, though not morphologically distinct, shows both allozyme and chromosomal divergence from Ecuadorean populations. Cladistic relationships based on overall allozyme data do not support species distinction, but a novel electrophoretic phenotype for glutathione reductase is shared only by individuals ofE. candida. An apparent geographic component within the monophyletic groups resolved in the cladogram suggests that some degree of gene flow between these two species has been maintained without the complete loss of morpholgoical species identity. This may have been mediated either by artificial population structures due to a probable long history of cultivation, or via Pleistocene refugia effects. Both species may have originated in eastern Ecuador from a common ancestral population which has since radiated outward, perhaps several times.
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    Plant systematics and evolution 166 (1989), S. 45-67 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Espeletia ; Diallel cross ; pollen donors ; parental effects ; outcrossing distance ; inbreeding ; seed abortion ; incompatibility ; pollen tube growth
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    Notes: Abstract The influence of different pollen donors on seed formation was investigated in three populations ofEspeletia schultzii that differ in environmental conditions and life history characteristics. Self pollen and pollen from different donors (〈 15m apart) within each population was used in a diallel design in order to test the genetic base of seed set variation. Three measures of seed formation were used: (1) achene number; (2) proportion of filled achenes (fruits) that distinguishes between achenes with seeds and empty achenes; (3) proportion of aborted seeds that distinguishes between viable and aborted seeds. Self-pollinations resulted in empty achenes. Achene number did not vary between the different pollen donors. A bimodal pattern of filled achenes was found in two populations in two consecutive years. On the other hand, a unimodal pattern was found in crosses between more distant donors (〉 30m). These patterns seems to be the results of a sporophytic incompatibility system. Seed abortion was highest at the higher elevations and seems to be correlated with elevation rather than with any genetic effect.
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    Plant systematics and evolution 166 (1989), S. 69-78 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Leguminosae ; Medicago lupulina ; M. secundiflora ; Chromosomes ; karyotypes ; chloroplast DNA evolution ; phylogeny
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    Notes: Abstract Studies were made on the chromosome complements and chloroplast genomes ofMedicago lupulina andM. secundiflora, which comprise sectionLupularia ofMedicago. Both types of analyses indicated more substantial differences between these species than suggested by external morphology.Medicago lupulina has a relatively asymmetrical karyotype in terms of centromeric position and relative length. The karyotype ofM. secundiflora is comparatively more asymmetrical in centromeric position and reduced in absolute size but exhibits greater symmetry in relative length. The restriction endonuclease fragmentation patterns of the chloropiast DNA of these two species (with Bam HI, Eco RI, Bgl II, and Xho I) show little similarity, with only 17% of the fragments matching in size. The lack of interspecific congruence among data of morphology, karyology and cpDNA inLupularia is contrary to consistency exhibited among these data inMedicago subsect.Intertextae.
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    Plant systematics and evolution 166 (1989), S. 131-139 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Najadaceae ; Najas marina ; Isozymes ; polyploidy ; Polymorphism
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    Notes: Abstract The genetic variability of five natural populations ofNajas marina L., i.e. one diploid of subsp.marina (Europe), two of subsp.intermedia (Europe) and both a diploid (C. Africa) and a tetraploid (Middle East) of subsp.armata, has been estimated by means of electrophoretic studies. These populations differ in their morphology and karyotype. Emphasis is placed on the characteristics and status of a tetraploid cytotype from Merkaz Sappir (Israel). Almost all the variation observed is expressed in seed alcohol dehydrogenase (ADH). The differences are in a unique allele of theAdh-2 locus and in the formation of novel heteromeric isozymes.Adh genes in seeds can be used as a marker for the autotetraploid character. The other enzyme systems tested failed in this respect. The genetic variability based on 23 loci is rather low. Nevertheless, the autotetraploid population has a higher or equal ratio of polymorphic loci than the related diploids. Cluster analysis illustrated not only thatNajas marina subsp.marina has diverged much from subsp.intermedia and subsp.armata, but also showed the difference between the latter two taxa, as well as the intermediate position of the autotetraploid population.
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    Plant systematics and evolution 166 (1989), S. 183-196 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Myrtaceae ; Eucalyptus ; E. clöeziana ; Monocalyptus ; Floral morphology ; operculum ; androecium ; staminophore ; phyllotaxy
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    Notes: Abstract Flowers ofEucalyptus clöeziana have two clearly distinct perianth whorls. The small free parts of the outer (calycine) whorl cease growth early and are lost from the flower; the parts of the inner (corolline) whorl become continuous laterally by confluence of growth centres and form an operculum in the mature flower. The stamens are inserted on a circumfloral buttress (staminophore) that is homologous to the adaxial corolline component inAngophora and the bloodwood andEudesmia eucalypts. Flowers ofMonocalyptus have only one perianth whorl, which is opercular. The stamens are similarly inserted on a circumfloral buttress. Developmental study does not provide conclusive evidence for either a calycine or corolline determination of theMonocalyptus operculum, but comparison with other eucalypt groups, includingE. clöeziana (the sister taxon), predicts an essentially corolline composition.
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    Plant systematics and evolution 166 (1989), S. 211-223 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Triticeae ; Hordeum brachyantherum ; H. californicum ; H. capense ; H. secalinum ; Morphometrics ; cluster analysis ; classificatory discriminant analysis ; canonical analysis ; sheared principal component analysis ; bootstrap validation ; identification key
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    Notes: Abstract Field collections and 296 herbarium sheets were examined for 27 morphometric variables. A priori species identifcation was based on geographical distribution except forH. californicum, a diploid species primarily occurring in California and differing from the much more widespread tetraploidH. brachyantherum that thrives in N. America and N.E. Asia;H. capense grows in S. Africa andH. secalinum mainly in Europe. Various cluster analyses were used followed by cluster recovery verification. Classificatory discriminant analysis and validation by the bootstrap yielded 85–90% overall total correct classification of the four species. Canonical analysis revealed thatH. californicum occupies an intermediate phenetic position among the other three distinct species. Factors of shape differences were unravelled and portrayed by shearing. A revised key to species was drawn up.
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    Plant systematics and evolution 166 (1989), S. 225-241 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Geraniaceae ; Geranium caespitosum ; Breeding system ; ecotype ; gynodioecy ; pollen sterility ; self-fertility ; selfing ; inbreeding depression ; stigma receptivity
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    Notes: Abstract Characters that have the potential to alter the breeding system ofGeranium caespitosum were investigated. The characters differ mechanistically, functioning either endogenously and independent of pollen transfer, or exogenously by influencing pollen transfer. Little variation in self-fertility (endogenous mechanism) was measured among populations from different elevations grown in a common garden. Variation in floral morphology (exogenous mechanism) was limited and unlikely to create a change in the breeding system. Macroscopic variation (exogenous mechanism), including gynodioecy, sexual specialization, and pollen sterility, was observed in extreme elevation populations and probably has a sizeable effect on the breeding system.
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    Plant systematics and evolution 166 (1989), S. 249-252 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Primulaceae ; Cyclamen ; C. somalense ; Taxonomy ; phytogeography ; Mediterranean floristic element ; Flora of Somalia
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    Notes: Abstract Cyclamen somalense Thulin & Warfa, spec. nova, the first member of the genus known from tropical Africa, is described from the Al Miskat Mts in NE. Somalia. The new species is closely related to the E. MediterraneanC. persicum Mill. The disjunct Mediterranean element in the mountain flora of northern Somalia, to whichC. somalense belongs, is believed to be largely a relict of Tertiary origin.
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  • 39
    ISSN: 1615-6110
    Keywords: Angiosperms ; Ranunculaceae ; Ranunculus cantoniensis ; R. chinensis ; R. silerifolius ; Amphidiploid ; aneuploid induction ; cytotaxonomy ; fertility ; habitat segregation ; hybrid ; multivalent ; speciation
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    Notes: Abstract Cytogenetical studies were carried out on the successive generations of offsprings from the induced tetraploid hybrid (2n = 32) betweenRanunculus silerifolius (2n = 16) andR. chinensis (2n = 16). Aneuploids, 2n = 30 to 35, frequently occurred. In latter subsequent generations the deviation of aneuploids increased, but the proportion of euploids decreased, accompanied by the reduction of fertility of pollen grains and seed sets. F2 and F4 PMCs constantly exhibited meiotic abnormality, i.e. formation of quadrivalents and univalents. The speciation process ofR. cantoniensis (2n = 32), which was presumed to arise from tetraploid hybrids between the above two species, is discussed on the basis of the above evidences.
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    Plant systematics and evolution 167 (1989), S. 137-148 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Orchidaceae ; Leporella ; Formicidae ; Myrmecia ; Ant pollination pseudocopulation ; floral morphology
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    Notes: Abstract Leporella fimbriata is a self compatible orchid of southern Australia. It is dependant across its range on unique pollination by sexually attracted male winged antsMyrmecia urens, which pseudocopulate with the flower. Typical pollination sequences began with an initial circling then zig-zag flight to the flower. Vectors usually alighted on the inflorescence stem and quickly crawled to the flower where they adopted a copulatory position sideways along the wide labellum, pseudocopulatory probing immediately followed. In this position pollen carried on the thorax was deposited on the stigma. Departure from the labellum usually resulted in pollinium removal. Pollinator movements were restricted and the distribution leptokurtic with a mean of 3.141 ± 4.59 m. Pollination was widespread but variable from site to site and season to season with a maximum of 70% of all flowers being pollinated. Pollinator limitation is indicated. Traits essential for this pollination interaction include the coincidence of orchid and ant geographic distributions and the coincidence of flowering with the flight period of the ant. The production of pheromonelike substances and the distinctive floral morphology are also essential for attraction and manipulation of male ants. The ant mating system which the orchid can exploit is also important.
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    Plant systematics and evolution 167 (1989), S. 189-194 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Magnoliidae ; Annonaceae ; Annona ; Rollinia ; Beetle pollination ; flower evolution
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    Notes: Abstract Dynastid scarab beetle pollination appears basic within the genusAnnona. Those species ofAnnona which are more morphologically derived, as well as allRollinia spp. possess reduced floral chambers and attract small beetles likeNitidulidae orStaphylinidae. Pollination of the primitive species ofAnnona byDynastinae would imply that the genus had not evolved before the Tertiary. The fossil record is in congruence with this hypothesis. Once again it is stressed that the cantharophilous syndrome, as it is found in theAnnonaceae, Magnoliaceae, Eupomatiaceae andCalycanthaceae, with beetles being exclusive pollinators, is a secondary and derived condition and obviously different from the expected basic entomophily of the original angiosperms.
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    Plant systematics and evolution 168 (1989), S. 49-57 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Hypochoeris ; Karyotype ; karyogram ; idiogram ; basic chromosome number ; symmetry of karyotype ; asymmetrical index
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    Notes: Abstract FiveHypochoeris spp. from Sicily have been investigated:H. glabra L. (2n=10),H. radicata L. (2n=8),H. cretensis L. (2n=6),H. laevigata L. (2n=12),H. robertia Fiori (2n=8). Basic chromosome numbers are very variable, x = 3, 4, 5, 6. The karyotype of each species is presented. Geographical origin (S. America or Mediterranean region) of the genusHypochoeris and the taxonomic position ofH. robertia are discussed.
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    Plant systematics and evolution 168 (1989), S. 143-148 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Caryophyllaceae ; Silene sect.Siphonomorpha ; sect.Auriculatae ; Crossing experiments
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    Notes: Abstract Ten species in the genusSilene sectt.Siphonomorpha andAuriculatae were crossed artificially involving 612 crosses to test inter- and infraspecific, intervarietal and intersectional crossability. In sect.Siphonomorpha all interspecific crosses (between diploids) failed due to cross- or seed-incompatibility; however, intervarietal crosses betweenS. gigantea var.gigantea andS. gigantea var.incana produced hybrids. In sect.Auriculatae hybrids were produced betweenS. vallesia andS. boryi, both tetraploids, but crosses between these and the diploid species were unsuccessful. The delimitation and status of the species in both sections was supported by the crossing results.
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    Plant systematics and evolution 168 (1989), S. 159-165 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Orchidaceae ; Coryanthes ; Fragrance analyses ; 2-N-methylaminobenzaldehyde ; taxonomic studies
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    Notes: Abstract All members of the investigated genusCoryanthes (subtribeStanhopeinae) are pollinated by male euglossine bees. The different fragrance profiles are the primary reproductive isolating mechanisms, because the flowers are interfertile. The fragrance patterns of 17 species ofCoryanthes were analyzed by gas chromatography as a means to improve the classification of this genus. A first amine (2-N-methylaminobenzaldehyde) was found to be the main fragrance compound of an as yet unclassifiedCoryanthes species.
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    Plant systematics and evolution 168 (1989), S. 221-225 
    ISSN: 1615-6110
    Keywords: Angiosperms ; monocotyledons ; Araceae ; Pothos sect.Allopothos ; Pothos crassipedunculatus ; spec. nova ; Taxonomy ; systematics ; Flora of India
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    Notes: Abstract Pothos crassipedunculatus Sivadasan & Mohanan (Araceae), a new species closely related to the SW. Indian endemic and little known speciesP. thomsonianus Schott is described. It is characterized by the the non-ligulate, shortly vaginate petiole, thickly peduncled inflorescence, broadly ovate spathe and a sessile spadix. It is included in ser.Brevivaginati Engler of sect.Allopothos Schott.
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    Plant systematics and evolution 168 (1989), S. 123-141 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Liliiflorae ; Liliales ; Dioscoreales ; Asparagales ; Cladistics ; relationships ; taxonomy
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    Notes: Abstract Comparisons between previous intuitive or phenetic classifications of the netveinedLiliiflorae was used to determine a suitable group of taxa for cladistic analyses. The resultant 48 genera and generic groupings comprising 19 families from within theAsparagales, Liliales andDioscoreales were then analysed. The cladistics largely supported previous treatments, with theLiliales, Dioscoreales andAsparagales all monophyletic.
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  • 47
    ISSN: 1617-4623
    Keywords: Meiosis ; Saccharomyces cerevisiae ; Sporulation ; Inessential genes ; Meiosis
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    Notes: Summary SPR3 is one of at least nine genes which are expressed in sporulating Saccharomyces cerevisiae cells at the time of meiosis I. We show below that strains homozygous for null alleles of SPR3 are capable of normal meiosis and the production of viable ascospores. We have also monitored SPR3 expression in a series of strains that are defective in meiotic development, using an SPR3: lacZ fusion carried on a single copy plasmid. β-Galactosidase activity occurred at wild-type levels in diploid strains homozygous for mutations in spo13, rad50, rad57 and cdc9, but was greatly reduced in strains carrying cdc8 or spo7 defects. We conclude that SPR3 expression is a valid monitor of early meiotic development, even though the gene is inessential for the sporulation process.
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    Molecular genetics and genomics 217 (1989), S. 149-154 
    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; HOM2 gene ; Aspartic semi-aldehyde ; General control
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    Topics: Biology
    Notes: Summary In Saccharomyces cerevisiae the HOM2 gene encodes aspartic semi-aldehyde dehydrogenase (ASA DH). The synthesis of this enzyme had been shown to be derepressed by growth in the presence of high concentrations of methionine. In the present work we have cloned and sequenced the HOM2 gene and found that the promoter region of this gene bears one copy of the consensus sequence for general control of amino acid synthesis. This prompted us to study the regulation of the expression of the HOM2 gene. We have found that ASA DH is the first reported enzyme of the related threonine and methionine pathway to be regulated by the general control of amino acid synthesis.
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    Molecular genetics and genomics 217 (1989), S. 464-470 
    ISSN: 1617-4623
    Keywords: Nucleosome positioning ; LEU2 gene ; Saccharomyces cerevisiae ; tRNA3 Leu gene ; Chromatin
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    Notes: Summary The chromatin structure of theLEU2 gene and its flanks has been studied by means of nuclease digestion, both with micrococcal nuclease and DNase I. The gene is organized in an array of positioned nucleosomes. Within the promoter region, the nucleosome positioning places the regulatory sequences, putative TATA box and upstream activator sequence outside the nucleosomal cores. The tRNA3 Leu gene possesses a characteristic structure and is protected against nucleases. Most of the 5′ flank is sensitive to DNase I digestion, although no clear hypersensitive sites were found. The chromatin structure is independent of either the transcriptional state of the gene or the chromosomal or episomal location. Finally, in the plasmid pJDB207, which lacks most of the promoter, we have found that the chromatin structure of the coding region is similar to that of the wild-type allele.
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    Molecular genetics and genomics 216 (1989), S. 511-516 
    ISSN: 1617-4623
    Keywords: Nonsense mutation ; Read-through ; Saccharomyces cerevisiae
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    Notes: Summary The yeast invertase structural gene SUC2 has two naturally occurring alleles, the active one and a silent allele called suc2°. Strains carrying suc2° are unable to ferment sucrose and do not show detectable invertase activity. We have isolated suc2° and found an amber codon at position 232 of 532 amino acids. However, transformants carrying suc2° on a multicopy plasmid were able to ferment sucrose and showed detectable invertase activity. Full-length invertase was found in gels stained for active invertase and in immunoblots. Therefore we concluded that the amber codon is occasionally read as an amino acid. The calculated frequency of read-through is about 4% of all translation events.
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    Molecular genetics and genomics 218 (1989), S. 293-301 
    ISSN: 1617-4623
    Keywords: Sporulation ; DNA sequence ; Saccharomyces cerevisiae ; Meiosis ; Chromosome segregation
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    Topics: Biology
    Notes: Summary Genetic studies have previously demonstrated that the RED1 gene of Saccharomyces cerevisiae is required for chromosome segregation at the first meiotic division. Northern blot hybridization analysis indicates that the RED1 gene produces two transcripts of 2.75 and 3.2 kilobases. The major 2.75 kb transcript is not present in mitotic cells and is meiotically induced to accumulate maximally just prior to the meiosis I division. The DNA sequence of the RED1 gene was determined and used to predict the amino acid sequence of the encoded gene product. The RED1 protein is 827 amino acids in length and has a molecular weight of 95.5 kilodaltons. There is no significant homology between the RED1 amino acid sequence and other known protein sequences, including those encoded by genes essential for meiosis.
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    Molecular genetics and genomics 215 (1989), S. 401-406 
    ISSN: 1617-4623
    Keywords: Protein secretion ; Saccharomyces cerevisiae ; Invertase ; Endoplasmic reticulum ; Secretion mutants
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    Topics: Biology
    Notes: Summary Intercompartmental transport of secreted proteins in yeast was analysed using invertase mutants. Deletions and insertions at the BamHI (position +787) or the Asp718 (position +1159) sites of the SUC2 gene led to mutant proteins with different behaviour regarding secretion, localization and enzyme activity. The deletion mutants showed accumulation of core glycosylated material in the endoplasmic reticulum (ER) a decrease of secreted protein by 5%–30% and loss of enzyme activity. The secreted material was localized in the culture medium and not — as is normal for invertase-in the cell wall. No delay in transport from the Golgi to the cell surface was observed, indicating that the rate-limiting step for secretion is at the ER-Golgi stage. Two insertion mutants, pIPA and pIPB, retained enzyme activity. Mutant pIPB showed 10% secretion, while 60%–70% secretion was observed for pIPA. While the non-secreted material accumulated in the ER, the secreted material was present in the cell wall. The results suggest that the presence of structures incompatible with secretion leads to ER accumulation of mutated invertase.
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    ISSN: 1617-4623
    Keywords: RNA splicing ; Maturase ; Recombinase ; Mitochondria ; Saccharomyces cerevisiae
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    Notes: Summary When the bI4 RNA maturase, encoded by the fourth intron of the mitochondrial cytochrome b gene of Saccharomyces cerevisiae, was expressed in Escherichia coli, formation of intra-chromosomal Lac+ recombinants was stimulated threefold. This “hyper-rec” phenotype was recA as well as recBCD dependent. The most active form of the bI4 maturase stimulated homologous recombination whereas splicing deficient mutants of bI4 maturase were either deficient in or unable to stimulate homologous recombination.
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  • 54
    ISSN: 1617-4623
    Keywords: Nucleotide sequence ; PET gene ; Mitochondrial import ; Saccharomyces cerevisiae
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    Notes: Summary Translation of mitochondrial cytochrome b mRNA in yeast is activated by the product of the nuclear gene CBS1. CBS1 encodes a 27 kDa precursor protein, which is cleaved to a 24 kDa mature protein during the import into isolated mitochondria. The sequences required for mitochondrial import reside in the amino-terminal end of the CBS1 precursor. Deletion of the 76 amino-terminal amino acids renders the protein incompetent for mitochondrial import in vitro and non-functional in vivo. When present on a high copy number plasmid and under the control of a strong yeast promoter, biological function can be restored by this truncated derivative. This observation indicates that the CBS1 protein devoid of mitochondrial targeting sequences can enter mitochondria in vivo, possibly due to a bypass of the mitochondrial import system.
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  • 55
    ISSN: 1617-4623
    Keywords: Mitochondrial introns ; Reverse transcriptase ; Saccharomyces cerevisiae
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    Notes: Summary Some pet- (or mit-) mutations impeding the splicing of one or several intron(s) of the yeast mitochondrial pre-mRNA(s) are suppressed in vivo by the DNA deletion of these introns. We have genetically demonstrated that introns aI1 and/or aI2 of the cytochrome c oxidase subunit 1 gene are necessary for this deletion process. The facts that adjacent introns are simultaneously deleted and that, in the pet- (or mit-) mutants which easily revert by intron deletion, the splicing of the introns they affect is only partially blocked, suggest that the intron encoded proteins aI1 and/or aI2 could intervene by means of their putative reverse transcriptase activity.
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  • 56
    ISSN: 1615-6110
    Keywords: Angiosperms ; Leguminosae ; Medicago truncatula ; Medicago littoralis ; Bruchidius bimaculatus ; Bruchid infestation
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    Topics: Biology
    Notes: Abstract The bean weevilBruchidius bimaculatus was found in fruits of 68 of 217 populations of theMedicago truncatula — M. littoralis complex of Israel, Greece, Italy and Spain. Infestation was higher in fruits of somewhat larger than mean size, and in the more pubescent and tightly coiled fruits. Bean weevil size proved to be independent of fruit size, so that the “preference” for larger fruits does not seem due to adaptation to a larger food source or a larger domicile. Fruit size has been used to delimit the host “species”M. truncatula andM. littoralis, but the character proved to be unimodal, and it is apparent that the taxonomy of the plant complex requires further clarification. Of the 11 472 fruits examined, less than 4% were infested. Given that the plants have evolved indehiscent legumes in which typically only one of the approximately six seeds survives to reproduce, and that very few seeds of a fruit are destroyed, the bruchid's infestation appears to be non-harmful, and indeed the association may be mutualistic.
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  • 57
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    Plant systematics and evolution 163 (1989), S. 53-69 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Liliaceae ; Lilium ; C-banding ; heterochromatin ; karyosystematics ; karyotype
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    Topics: Biology
    Notes: Abstract C-band patterns are described for 20Lilium spp. distributed across six sections. All species have a similar basic karyotype (n = 12) but C-bands differ markedly between them. The patterns are characterized by a dispersed scattering of thin intercalary bands as well as centric and NOR bands. Only one species,L. canadense, shows a clear equilocal pattern with intercalary C-bands occurring proximally in all of the longer chromosome arms. Comparing species, similar patterns are revealed forL. regale andL. sulphureum, forL. formosanum andL. longiflorum (all in sect.Leucolirion) and to a lesser extent forL. hansonii, L. martagon, andL. tsingtauense (sect.Martagon). The pattern forL. henryi (previously classed in sect.Sinomartagon) matches those ofL. regale andL. sulphureum quite well and its transfer to sect.Leucolirion is proposed. This is consistent with results from interspecies hybrids betweenL. henryi andL. regale (and related species) which are reportedly fertile. No other clear similarities in C-band patterns were seen across species. It seems that C-band patterns change rapidly inLilium and hence their usefulness in classification will be restricted to identifying closely related species.
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  • 58
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    Plant systematics and evolution 163 (1989), S. 81-85 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Ranunculaceae ; Anemone ; Pulsatilla ; Hepatica ; Chloroplast DNA ; restriction endonuclease analysis
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    Topics: Biology
    Notes: Abstract Chloroplast DNA of seven species belonging toAnemone (sectt.Omalocarpus, Anemonidium, andAnemonanthea),Hepatica, andPulsatilla have been analyzed by restriction enzymes. According to the dendrogram constructed, the sections ofAnemone and the generaHepatica andPulsatilla seem to be evolutionary approximately equidistant to each others. This supports the concept that these groups should be treated on a similar taxonomic level, either as genera or subgenera.
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  • 59
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    Plant systematics and evolution 163 (1989), S. 87-92 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Alliaceae ; Allium ; B-chromosomes ; nucleolar activity
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    Topics: Biology
    Notes: Abstract Nucleolar activity was analyzed in two samples of plants of the wild onion speciesAllium cernuum, one from Canada (2n=14) and one from the United States of America (2n=14+3B), using phase contrast analysis and C- and Ag-NOR-banding. Three chromosome pairs of the standard A-chromosome complement show small telomeric satellites, which corresponds to the maximum number of Ag-NOR-bands at metaphase and to the telomeric C-heterochromatin. However, the maximum number of nucleoli observed at interphase was eight, indicating that another chromosome pair possesses nucleolar activity. Corresponding results were obtained for the A-chromosome complement of plants from the United States of America, however, these plants further possess three small metacentric supernumerary chromosomes, which show telomeric satellites on both arms, corresponding to two telomeric Ag-NOR-bands observed after silver staining. The presented data clearly indicate that the B-chromosomes ofAllium cernuum possess rDNA gene clusters which show strong nucleolar activity.
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  • 60
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    Plant systematics and evolution 163 (1989), S. 93-105 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Leguminosae (Fabaceae) ; Caesalpinioideae (Caesalpiniaceae) ; Cassia ; Chamaecrista ; Senna ; Stigma morphology ; taxonomy ; floral ecology
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    Topics: Biology
    Notes: Abstract Two stigma forms occur inChamaecrista andSenna, but only one inCassia. In the common chambered form, a stigma pore is positioned on the reflexed style tip and is the entrance to a tapering chamber. The pore rim is fringed by hairs which vary in number, size, distribution and shape. In the alternative form the stigma is situated at the apex of the curved style and is crateriform. The crater rim is fringed by hairs of variable number and shape. The stigmatic hairs are predominantly unicellular and cutinized. Stigma and hair differences aid in the taxonomy of the genera. Their functions in pollination biology are discussed.
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  • 61
    ISSN: 1615-6110
    Keywords: Angiosperms ; Orchidaceae ; Orchis ; Dactylorhiza ; Gymnadenia ; Taxonomy ; interspecific relationship ; enzyme electrophoresis ; computer evaluation
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    Topics: Biology
    Notes: Abstract Ten species of orchid plants belonging to the generaOrchis (7),Dactylorhiza (2), andGymnadenia (1) were analyzed by enzyme electrophoresis. Each species can be identified by a combination of enzyme bands different from those of all other species examined. The electrophoretic data were used for the construction of phenetic and phylogenetic trees with the help of computer programs. The trees were almost identical regardless which method was used. Our results differ considerably from a classification based on morphological evidence. The electrophoretic data indicate that the genusOrchis is not a monophyletic group.
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  • 62
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    Plant systematics and evolution 163 (1989), S. 121-125 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Acanthaceae ; Justicia sect.Ansellia ; J. brevipedunculata ; spec. nova ; Flora of Tropical East Africa
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    Topics: Biology
    Notes: Abstract Justicia brevipedunculata, a new species ofJ. sect.Ansellia endemic to Tanzania, is described and illustrated. Detailed palynological information is given, and relationships to other species of the section are discussed.
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  • 63
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    Plant systematics and evolution 163 (1989), S. 127-131 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Portulacaceae ; Grahamia bracteata ; Chromosome number ; karyotype ; base number
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    Topics: Biology
    Notes: Abstract The somatic and gametic chromosomes of the monotypical genusGrahamia (G. bracteata) have been studied for the first time: 2n = 18, n = 9. The karyotype is symmetrical; of the nine m pairs one has microsatellites. The basic chromosome number x = 9 is considered to be primitive within the family.
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  • 64
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    Plant systematics and evolution 163 (1989), S. 147-152 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Beilschmiedia ; Calluna ; Polyalthia ; Strelitzia ; Acetolysis ; palynology ; sporoderm ; exine ; intine ; pollen characters
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    Topics: Biology
    Notes: Abstract The acetolysis method intreduced byGunnar Erdtman is still a very welcome and highly successful technique in palynology. However, acetolysis destroys all pollen material with the exception of sporopollenin that forms the outer pollen wall, the exine. Modern palynology in its application to plant systematics and phylogeny must consider all sporoderm characters, not only those of the exine. The neglect of the intine may distort some principal palynological aspects. This is illustrated by cases of total breakdown or gross modification of thin exine structures (e.g. inBeilschmiedia, Strelitzia) and by the clarification of apertures (e.g.,Polyalthia, Fissistigma, Calluna). In our view the investigation of both acetolysed and non-acetolysed pollen is obligatory for a well balanced view of pollen structure and function.
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  • 65
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    Plant systematics and evolution 163 (1989), S. 133-146 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Cucurbitaceae ; Cucumis ; C. sativus ; C. melo ; C. metuliferus ; C. anguria ; C. zeyheri ; C. myriocarpus subsp.leptodermis ; comb. nov. ; Crossing experiments ; meiosis of hybrids ; polyploidy ; isozymes ; DNA analysis ; evolution
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    Notes: Abstract Meiosis in seven interspecificCucumis hybrids has been analysed i.a. inC. metuliferus ×C. zeyheri, where the parents belong to different sections. In the triploid hybrids a remarkably high number of trivalents has been found. Additional data from literature on geographical distribution, cucurbitacins, flavonoid patterns, isozymes, C-banding, genome size, DNA amount and chloroplast DNA are used to discuss species relationships and evolution. The African cross-compatible group is divided into theMyriocarpus subgroup with the diploid speciesC. africanus, C. myriocarpus subsp.leptodermis and subsp.myriocarpus, and theAnguria subgroup withC. anguria, C. dipsaceus, C. ficifolius, C. prophetarum, C. zeyheri and all polyploids (exceptC. heptadactylus). It is argued that the Asian subg.Melo with x = 7 is derived from the African subg.Cucumis with x = 12; the latter contains all the polyploid species and has the most common basic chromosome number of theCucurbitaceae. This phylogenetic advance is interpreted with concepts of the quantum model of evolution.
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  • 66
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Taraxacum ; Agamospermy ; NOR-chromosome ; chromosomal rearrangement ; transposable genetic elements
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    Topics: Biology
    Notes: Abstract Morphological variation for the NOR chromosome was studied for four half-siblings of a sexual outbreedingTaraxacum, for three siblings of the obligate agamospermT. pseudohamatum, and for two individuals of the agamospermT. brachyglossum. No rearrangement was detected for the 113 chromosomes of sexuals, or for 41 chromosomes of two agamospermous individuals. In the other three agamospermous individuals, 3/16, 5/50, and 5/20 chromosomes showed evidence of chromosomal rearrangement. The majority of rearrangement events (10/13) occurred to the satellite rather than to the body of the NOR-chromosome. It is considered that such high levels of somatic chromosomal rearrangement in agamospermousTaraxacum may be the result of activity by transposable genetic elements. This recombination may be of selective advantage to asexual plants which cannot generate genetic variability through the sexual process.
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  • 67
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    Plant systematics and evolution 163 (1989), S. 211-226 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Loasaceae ; Petalonyx ; Inflorescence ; floral ontogeny ; vascular pattern ; androecium ; gynoecium ; nectary ; symmetry
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    Notes: Abstract Inflorescence and floral structure ofPetalonyx linearis are described to assist in understanding homologies among the diverse flowers ofLoasaceae. The inflorescence consists of racemose axes, along which each individual flower is recaulescent with its subtending leaf. Both floral vascularization and appendage initiations show a set of variations. The pseudomonomerous gynoecium may be derived from a triplacental condition. Nectary position, on a collar on which the perianth and androecium are inserted, appears homologous to the ovarian dome position of the nectary among otherLoasaceae.
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    Plant systematics and evolution 163 (1989), S. 201-209 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Iridaceae ; Moraea inclinata ; M. brevistyla ; Bees ; Anthophoridae ; Halictidae ; Pollination mechanism ; flower morphology
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    Topics: Biology
    Notes: Abstract Individual flowers ofMoraea inclinata are nectariferous and last about six hours. They appear to be pollinated largely by bees in the familyHalictidae (Lasioglossum spp.,Nomia spp.,Zonalictus) and to a lesser extent by bees in the familyAnthophoridae (Amegilla). The mechanism of bee-pollination inM. inclinata is the “Iris type”; i.e., each flower consists of three pollination units (an outer tepal, a partly exserted anther, and the opposed style branch which terminates in a pair of petal-like crests). Bees rarely visit more than one pollination unit per flower. Transferral of pollen to the bee is passive and nototribic although all bees collected on the flowers were female and 55% of the bees carried pollen loads with 2–5 pollen taxa in their scopae.Moraea brevistyla flowers are nectariferous but lack scent and last two days. They are visited infrequently by bees and only one femaleLasioglossum spec. carried the pollen ofM. brevistyla. Unlike flowers ofM. inclinata those ofM. brevistyla deposit pollen only on the head and thorax. Bee-mediated autogamy in both species is avoided due to the erratic foraging patterns of the bees and the flexibility of each stigma lobe as the bee backs out of the flower. Approximately 2–4 flowers in the inflorescences of both species (6–8 flowers/infloresence) develop into capsules.
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    Plant systematics and evolution 163 (1989), S. 187-199 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteraceae ; Marantaceae ; Inflorescence morphology ; monotely and polytely ; homogenization ; racemization ; truncation ; pseudoflorescence
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    Notes: Abstract In contrast toW. Troll's typology of inflorescences which aims at more or less rigid, well defined types, this investigation accentuates the processes that constitute the evolutionary transformations leading from one typical form to another.Troll divided the inflorescences into the two types of monotelic and polytelic synflorescences, the first with a terminal flower on the main axis, the latter with a homogeneous florescence on the indeterminate axis. Both forms are enriched by proximal branches which repeat the structure of the main axis (paracladia). The evolutionary processes leading from the more primitive monotelic type to the advanced polytelic type are truncation (loss of the terminal flower) and homogenization of the distal branches, which thus form a homogeneous florescence. A closer survey of the polytelic groups reveals the fact that, usingTroll's criteria, the same distinction can be found within these groups themselves. Loss of the terminal florescence (truncation of 2nd and higher degree) as well as homogenization of the distal paracladia may lead to florescence-like units of higher complexity. Examples can be found inAsteraceae (Figs. 1 and 2),Fabaceae (Fig. 3 a),Mimosaceae (Fig. 3 b),Acanthaceae, and also in Monocots, as exemplified by theMarantaceae (Figs. 4 and 5). The so-called racemization (inversion of efflorescences from basipetalous to acropetalous) may be mentioned as a third element of transformation, emphasizing the unity of the florescences.—In consequence, there are more organizational levels than reflected in the twoTroll types. The polytelic type comprises several degrees of truncation and homogenization, the basis for a reasonable organizational analysis should therefore be the degree of ramification of flowering branches rather than the mere question of a terminal flower on the main shoot axis (Fig. 6). On the other hand the three processes of truncation, homogenization and racemization are evolutionary transformations that may occur independently from one another, thus giving rise to a large number of variations, which can not be satisfactorily interpreted by exactly defined types. On the basis of these considerations the question of homologous parts in inflorescences is reviewed. The homology of partial florescences and paracladia is accentuated contrary toTroll's interpretation (Fig. 7). Homogenization as an evolutionary trend may transform paracladia of different degree of ramification, leading to one-flowered units on the one side and to highly complex structures as in theMarantaceae on the other.
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    Plant systematics and evolution 163 (1989), S. 227-280 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Papaveraceae ; Hypecoum ; Taxonomy ; morphological variation ; mating system ; autogamy ; UV-reflection ; pollen morphology ; chromosome numbers
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    Notes: Abstract Hypecoum sect.Hypecoum comprises 8 species, one with 2 additional subspecies, in the Mediterranean area and the Middle East. Five of these are recognized for the first time, viz.Hypecoum procumbens L. subsp.fragrantissimum Å. E. Dahl,H. procumbens L. subsp.atropunctatum Å. E. Dahl,H. trullatum Å. E. Dahl,H. angustilobum Å. E. Dahl andH. torulosum Å. E. Dahl. H. dimidiatum Delile andH. pseudograndiflorum Petr., which have generally been included inH. imberbe Sm., are reestablished as distinct species. Morphology and variation patterns are described and discussed with special reference to mating systems. Self-incompatibility is dominating butH. procumbens subsp.procumbens andH. torulosum are self-compatible. The broad variation ranges of the former taxon in traits presumably related to mating system (petal, anther and stigma sizes as well as pollenovule ratios) indicate varying rates of outcrossing. SEM micrographs are given of petal and stigma surfaces and of pollen grains. Chromosome counts are presented for seven taxa. All are diploid with 2n = 16.
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  • 71
    ISSN: 1615-6102
    Keywords: Microtubule neoformation ; Nocodazole ; Protoplasts ; Saccharomyces cerevisiae
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    Topics: Biology
    Notes: Summary By following microtubule neoformation after their complete destruction by nocodazole, we analyzed the pattern of microtubule nucleation in protoplasts ofSaccharomyces cerevisiae. Using immunofluorescence, the drug was shown to induce rapid and complete disassembly of both cytoplasmic and spindle microtubules and to selectively block protoplast nuclear division at a defined stage of the cell cycle. Treated protoplasts placed in a drug-free environment recovered a more abundant microtubular system. The majority of microtubules re-formed at SPBs whereas a minority of free-ended microtubules nucleated in the cytoplasm of the protoplasts without any detectable association with recognizable nucleation sites. Random nucleation of free microtubules might be induced by high amounts of unpolymerized tubulin likely to be present in the protoplasts at the moment of drug release.
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    Protoplasma 152 (1989), S. 57-64 
    ISSN: 1615-6102
    Keywords: Angiosperms ; Plastid inheritance, uniparental ; Plastid inheritance, biparental ; Plastid distribution ; Plastid transmission
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    Plant systematics and evolution 163 (1989), S. 1-12 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteridae ; Verbenaceae ; Oleaceae ; Nyctanthes ; Intranuclear inclusions ; mesophyll cells ; ultrastructure
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Abstract TEM observations were carried out on 40 taxa of the familyVerbenaceae and 35 taxa of the familyOleaceae, in order to ascertain distribution, ultrastructure and morphology of the intranuclear proteinic inclusions in the mesophyll parenchymatic cells. The investigated genera amount to some 25% and 60% respectively of the genera of the two families. Inside theVerbenaceae, lamellar inclusions (L-type) occur in 6 out of 23 investigated genera: they are mostly present inside the tribesCitharexyleae andVerbeneae (both belonging toVerbenoideae), while they are absent in other subfamilies. All of the investigatedOleaceae genera show intranuclear crystalline inclusions (C 1-type) of three different shapes. Among theAsteridae this is a character peculiar toOleaceae. They appear to be a well defined natural group, including the controversial genusNyctanthes.
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    Plant systematics and evolution 163 (1989), S. 13-20 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Aegilops cylindrica var.kastorianum ; New variety ; karyotype analysis ; protein and esterase patterns ; isoelectric focusing
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    Notes: Abstract A native population ofAegilops cylindrica was encountered for the first time in Greece in 1980 (near Kastoria, NW. Greece), completely isolated and at a great distance from its main distribution area. There are morphological and chromosomal, but no protein and esterase pattern differences from otherAe. cylindrica populations. This justifies the recognition of a new variety: var.kastorianum. Our comparative and karyotypic observations support the view thatAe. caudata var.polyathera and not var.caudata (typica) is the possible donor of genome C of the new variety.
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    Plant systematics and evolution 163 (1989), S. 31-34 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Aristolochiaceae ; Aristolochia krisagathra spec. nova ; A. indica ; Ornithoptera ; Taxonomy ; butterflies ; host plants ; Flora of India
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    Notes: Abstract Aristolochia krisagathra, a new species from the Western Ghats of Peninsular India is described, illustrated and included into a key to the four Indian species of the genus. Notes on the host-relationships of these species are also provided, paticularly ofA. indica to papilionid butterflies.
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    Plant systematics and evolution 163 (1989), S. 21-29 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Sarraceniaceae ; Melastomataceae ; Rapateaceae ; Gentianaceae ; Loranthaceae ; Malpighiaceae ; Ericaceae ; Orchidaceae ; Campylopterus duidae ; Diglossa duidae ; Anoura geoffroyi ; africanized honey bee ; Pollination by bees ; buzz pollination ; Flora of Neblina
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Abstract During 20 days in 1985, floral biological observations were made at 1 850–2 100m elevation on Cerro de la Neblina in Venezuela.Heliamphora tatei var.neblinae (Sarraceniaceae) is nectarless and has poricidal anthers.Heliamphora tatei, Graffenrieda fruticosa, G. polymera, G. reticulata, Tocca pachystachya, T. tepuiensis (Melastomataceae),Saxofridericia compressa, andStegolepsis neblinensis (Rapateaceae), are buzz-pollinated by ten species ofBombus, Eulaema, Melipona, Centris, Xylocopa, Dialictus, andNeocorynura. Additional observations of floral visits on tepui species ofGentianaceae, Loranthaceae, Malpighiaceae, Ericaceae, Orchidaceae, andAsteraceae are reported. Visitors include the hummingbirdCampylopterus duidae, the flower-piercerDiglossa duidae, the nectarivorous batAnoura geoffroyi, and various species ofCentris andBombus bees. Scent baits for euglossine bees attracted very few bees.Apis mellifera adansonii-scutellata, the africanized honey bee, was caught at 1 850m elevation.
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    Plant systematics and evolution 163 (1989), S. 71-79 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Ericaceae ; Arctostaphylos ; Arctous ; Calluna Erica ; Loiseleuria ; Rhododendron ; Rhodothamnus ; Oxycoccus ; Vaccinium ; Empetraceae ; Empetrum ; n-Alkanes ; epicuticular waxes ; chemotaxonomy ; environmental effects
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    Notes: Abstract Alkane distribution patterns were determined in the epicuticular wax of the leaves of 13 species and a hybrid fromEricaceae and one species ofEmpetrum (Empetraceae). As chemotaxonomic indicators, the results are of limited use only. The most uniform genus wasRhododendron, the most heterogeneousVaccinium. The dominant effect of genetic over environmental factors was apparent in most cases.
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    Plant systematics and evolution 162 (1989), S. 315-329 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Aceraceae ; Betulaceae ; Celastraceae ; Fagaceae ; Juglandaceae ; Oleaceae ; Rosaceae ; Staphyleaceae ; Summer-green woody plants ; submediterranean ; distribution types ; climatic conditions ; post-Pleistocene dispersal
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    Notes: Abstract The deciduous wood flora of southern Europe is characterized as a special “nemoral-Submediterranean element”. The distribution patterns of some representatives (total ranges and local areas in Roumania) are described and explained by recent climatic conditions. The northern limits of Submediterranean and Submediterranean-middle European deciduous forest taxa exhibit a continuous gradation, but only a few species with a wide ecological amplitude extend into the temperate zone.
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  • 79
    ISSN: 1615-6110
    Keywords: Angiosperms ; Hyacinthaceae ; Scilla cilicica ; S. morrisii ; Karyotype evolution ; C-banding ; genome size ; Endemism ; flora of Cyprus
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    Notes: Abstract S. cilicica Siehe andS. morrisii Meikle are two little known sibling species of theScilla siberica alliance with previously difficult taxonomy, especially with regard to specific delimitation and geographic distribution. Quantitative C-band karyotyping and DNA content determinations were performed in four provenances, including the type localities. Both species (2n = 12) differ strikingly in their banding patterns despite of similar DNA content. Karyotype diversification involved changes in eu- and heterochromatin quantities and resulted in some changes of chromosome form. Despite this, actual phylogenetic relatedness is indicated by a chromosomal marker (NOR-position) of rare occurrence in the alliance. Karyological results and circumstantial evidence from the literature suggest thatS. morrisii is an endemic, exclusive to Cyprus as a member of theS. siberica alliance.S. cilicica seems to be restricted to continental S. Anatolia opposite to Cyprus. Its occurrence on Cyprus is questionable.
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    Plant systematics and evolution 165 (1989), S. 95-100 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Gesneriaceae ; Didymocarpus ; Morphology ; floral ecology ; Flora of Malaysia ; SE. Asia
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    Notes: Abstract Didymocarpus geitleri spec. nov. is described from Sungai Pandan, Kuantan distr., Pahang, Peninsular Malaysia. Distinctive features include: leaden-grey leaves with long, erect hairs on the upper side and whitish, campanulate flowers with a long exserted, bright yellow style. The colouring of the latter is caused by densely arranged glands. Together with two yellow blotches in front of the filament insertion, the style apparently acts as an anther (pollen) dummy.
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  • 81
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    Plant systematics and evolution 165 (1989), S. 189-198 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Iridaceae ; Gladiolus ; G. atroviolaceus ; G. communis ; G. illyricus ; G. imbricatus ; G. italicus ; Geography ; morphology ; multivariate analysis ; chromosome numbers
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Abstract Representative specimens of the EuropeanGladiolus species (excl.G. palustris) were used to study variability and relationships. 25 characters were measured for cluster, principal component and Wells hybrid analyses (Figs. 1–3). Three (with PCA) respective five (cluster analysis) main groups are revealed. Bulb characteristics appear to be very useful for indentification. The subspecific status ofG. communis subsp.byzantinus is confirmed. Hybrids of four different parental combinations were detected in our collection. Most species include polyploid series. Partly 3x, 4x, 6x, 8x, 12x and aneuploid cytotypes but no diploids were found. Polyploids as pioneers and hybridization of sympatric species are apparently linked to migrations during the glacial periods.
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  • 82
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    Plant systematics and evolution 165 (1989), S. 239-254 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Myrtaceae ; Eucalyptus ; Eudesmia ; Floral morphology ; corolla ; operculum ; androecium ; staminophore ; growth centres ; continuity ; heterotopy ; epipetaly
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    Notes: Abstract In the early stages of ontogeny, the corolline parts of theEudesmia eucalypts develop as compound structures directly comparable to the early stages of the petals ofAngophora and the bloodwood eucalypts, but with the onset of androecial formation a marked difference takes place. Rather than forming on the floral apex, the stamen primordia arise on the basal adaxial components of the young corolline parts; this basal component develops into the staminophore of the mature flower. The operculum consists only of the dorsal components of the corolline parts, the homologues of the “dorsal keels” of theAngophora petals. If the corolline parts remain more or less free in their early developmental stages, corresponding groups of stamens are produced. Early corolline continuity leads to a continuous ring of stamens. The staminophore is not an organ sui generis, but a derivative of the corolla. The bundles of stamens in some species are best referred to as epipetalous groups, not antepetalous fascicles.
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  • 83
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    Plant systematics and evolution 166 (1989), S. 91-104 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Agropyron ; Elymus ; Biometrics ; Wells' distance diagram ; morphological variation ; Flora of S. America ; Patagonia ; Tierra del Fuego ; Falkland Islands
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    Notes: Abstract Based on a simple multivariate analysis of the morphology of theAgropyron pubiflorum complex—A. patagonicum, A. antarcticum, A. fuegianum, andA. magellanicum—the variation pattern is shown to be clinal, and all taxa are included in a single, variable species. Currently the majority of species ofAgropyron is included inElymus and the correct name of this species isE. glaucescens.
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  • 84
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    Plant systematics and evolution 166 (1989), S. 79-89 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Liliaceae ; Hyacinthaceae ; Ornithogalum tenuifolium ; Evolution of karyotypes ; bimodal karyotypes ; DNA content ; Feulgen densitometry ; hybrids ; meiotic chromosome pairing ; fitness
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    Notes: Abstract Hypotheses on the evolution of the karyotypes of 8 chromosome races (2n = 4, 6, 8, 10, 12, 16-two forms, 26) within theOrnithogalum tenuifolium complex are discussed. Four of the karyotypes are strictly bimodal: 2n = 8 (6 long and two short chromosomes), 2n = 10 (6 long and 4 short chromosomes), 2n = 12 (6 long and 6 short chromosomes) and 2n = 16 (12 long and 4 short chromosomes). The hypotheses are tested by means of measurements of nuclear DNA content, studies of meiosis and pollen fertility of hybrids, and comparisons of karyotype morphology. The results indicate that the E. African 2n = 12 chromosome race is the most primitive and has given rise to the other chromosome races. The 2n = 6 race is found to have a significantly higher fitness than the 2n = 12 race.
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  • 85
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    Plant systematics and evolution 166 (1989), S. 141-158 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Proteaceae ; Conospermum taxifolium ; C. longifolium ; Biosystematics ; numerical taxonomy ; morphology ; allozymes ; electrophoresis ; Flora of Australia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A morphometric analysis of 18 attributes of 110 plants of theConospermum taxifolium complex suggests that it consists of three polythetically distinct taxa, corresponding to the traditional concepts ofC. taxifolium Smith s. str.,C. ericifolium Smith andC. ellipticum Smith. Discrimination is possible on the basis of leaf but not flower attributes. Analysis of allozymic variation indicates that the taxa are also genotypically differentiated.C. ericifolium andC. ellipticum are geographically isolated from each other but not fromC. taxifolium, andC. taxifolium is usually ecologically segregated from the other two taxa. Where this ecological segregation breaks down, morphological intermediates sometimes occur as the result of hybridization.
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  • 86
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    Plant systematics and evolution 166 (1989), S. 173-181 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Eragrostis curvula ; Lovegrasses ; Esterase isozymes ; disc electrophoresis ; biosystematics
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    Notes: Abstract The biosystematic relationships of the apomictic complexEragrostis curvula s. lato, is investigated by disc electrophoresis of seed extracts to obtain esterase patterns of 23 accessions representing the morphological variants of this complex: curvula, conferta, robusta, chloromelas and lehmanniana. The zymograms thus obtained were classified into four groups on the basis of the presence of certain bands taken as characteristic and constant markers. Within each group variations were found in strict accordance with the morphological and cytogenetic data available on the complex. Cluster analysis showed similarity levels between the strains studied, representing different genomic groups. The esterase pattern proved useful as an additional criterion for identifying the individual taxa making up the complex and for evaluating their reciprocal relationships.
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  • 87
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    Plant systematics and evolution 167 (1989), S. 43-57 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Chenopodiaceae ; Chenopodium ; Taxonomic trees ; phenograms ; cladograms ; natural classifications ; predictivity ; information content ; probability of trees
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    Notes: Abstract The contribution ofJ. S. L. Gilmour to numerical taxonomy is reviewed. His important concept of natural classification, as being general-purpose classifications with high predictivity, led to the development of ideas of information content, unit characters and equal character-weighting. The concept of predicitivity is extended to taxonomic trees (phenograms or cladograms). Under certain assumption of random sampling of characters it is shown that the probability of recovering the correct tree topology or tree-form may be small if characters are few. There may be very many topologies or tree-forms, every one of which has individually a low probability. It is, however, possible to estimate the aggregate probability of trees which have more than some specified resemblance to the “correct” tree. The practical prospects of estimating the distribution of tree probabilities are discussed.
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  • 88
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    Keywords: Angiosperms ; Ranunculaceae ; Ranunculus auricomus agg. ; Ranunculus marsicus ; Cytofluorimetry ; polyploidy ; agamic complex
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    Notes: Abstract A cytofluorimetric method for DNA amount determination on nuclei released from fixed leaves has been successfully tested on samples belonging to the polyploid series ofRanunculus marsicus Guss & Ten. (sect.Auricomus). The procedure was devised to screen rapidly for different ploidy levels within topodemes and progenies.
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  • 89
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    Plant systematics and evolution 168 (1989), S. 7-18 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Fagaceae ; Castanea ; Lithocarpus ; Comparative morphology ; cupule ; ontogenetic development
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    Notes: Abstract Two contradicting theories have been proposed for the morphological nature of fagaceous cupules; the intercalary growth theory and the higher order dichasial branch theory. All the previous ontogenetic studies insist on the latter one, but the genera investigated have been rather restricted and have not covered all the cupule types. A comparative study of the ontogenetic development of cupules inCastanea crenata andLithocarpus edulis, which are representatives of fundamentally different cupule types, revealed that both the theories are incomplete. InL. edulis, the higher order dichasial branches contribute to cupule formation along the anterior portions of the lateral flowers. However, along the adaxial portion of the central flower, the cupule develops as an intercalary growth, represented by rapid increase of tangentially oblong epidermal cells. InCastanea, intercalary growth is not clearly observable, for presumably, the flowers are surrounded by a well-developed partial inflorescence mound from the beginning of development.
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    Plant systematics and evolution 166 (1989), S. 159-171 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Triticeae ; Biosystematics ; genome analysis ; chromosome homology ; phylogenetic reconstruction ; classification
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    Notes: Abstract The implications of genome analysis for evolutionary theory and systematics are treated. The precise relationship between the theoretical and operational definitions of chromosome homology is shown to be uncertain. It is pointed out that genera defined by genome analysis may be either monophyletic or non-monophyletic, and that the genus is not a basic unit of evolution. Characters obtained by genome analysis may be useful in a phylogenetic context, provided they are treated as all other characters.
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  • 91
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    Plant systematics and evolution 166 (1989), S. 243-248 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Viscaceae ; Viscum ; Nuclear DNA content ; DNA denaturation ; DNA reassociation ; host-specific DNA organization ; subspecific genome differentiation
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    Notes: Abstract The nuclear DNA content and composition with respect to base composition and the proportion of repetitive DNA was studied in the host-specific mistletoe subspecies,Viscum album subsp.album, V. a. subsp.abietis andV. a. subsp.laxum, using DNA ofLoranthus europaeus as a standard. Small but not significant differences were found between the 2C DNA contents and the base composition but significant differences were detected in the patterns of sequence organization. This infraspecific variation is briefly discussed in the light of differences known to occur in the patterns of lectins and viscotoxins, immunostimulating and cancerostatic effects.
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  • 92
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    Plant systematics and evolution 166 (1989), S. 253-264 
    ISSN: 1615-6110
    Keywords: Angiosperms ; orchids ; Pleione ; P. bulbocodioides ; P. formosana ; P. yunnanensis ; P. humilis ; P. forrestii ; Chromosome banding ; Feulgen staining ; karyotype analysis ; epiphytic ; semi-terrestrial ; terrestrial habitats
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    Notes: Abstract Karyotypic and heterochromatin studies suggest a basic division of the orchid genusPleione into two groups, one represented by the clearly epiphytic species and the other including both species with terrestrial trends as well as those that are truly terrestrial. The epiphytic group possesses only (sub) metacentric chromosomes and is characterised by a considerable amount of terminal heterochromatin while the terrestrial group has some subtelocentric chromosomes and only small amounts of centromeric heterochromatin. It is concluded that a major phyletic split in the mode of chromosome change occurred during the transition from the epiphytic to the terrestrial habitat.
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  • 93
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    Plant systematics and evolution 167 (1989), S. 113-127 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Boraginaceae ; Symphytum ; S. officinale agg. ; Chemotaxonomy ; pyrrolizidine alkaloids ; isobauerenol
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    Notes: Abstract In a chemotaxonomic study of the genusSymphytum pyrrolizidine alkaloids and triterpenes were used as chemotaxonomical markers. A micro-extraction methods was developed for screening compounds of very small pieces of herbarium material. The occurrence of the pyrrolizidine alkaloids symphytine and (acetyl-)lycopsamine is very general forSymphytum taxa. Echimidine is present in someS. officinale L. plants and inS. tanaicense Steven. The triterpene isobauerenol is present inS. officinale, S. bohemicum Schmidt,S. tanaicense and inS. officinale var.lanceolatum Weinm. The chemotaxonomic hypothesis, proposed byGadella and collaborators, based on the presence of the triterpene isobauerenol inS. officinale and its absence inS. asperum Lepech. and the presence of the pyrrolizidine alkaloid echimidine inS. asperum and its absence inS. officinale, can no longer be applied absolutely to theS. officinale species complex. The pyrrolizidine alkaloid and triterpene pattern ofS. officinale (2n = 24) andS. bohemicum (2n = 24) is identical.S. bohemicum is morphologically, cytologically and phytochemically very similar toS. officinale. Furthermore, it readily crosses with the white flowered W. European diploids ofS. officinale. Therefore it seems likely that these two taxa are conspecific.S. tanaicense shows a pyrrolizidine alkaloid and triterpene pattern similar toS. officinale (2n = 40). Also on morphological and cytological grounds they are very similar. It seems highly probable thatS. tanaicense is conspecific withS. officinale (2n = 40) and represents an intraspecific variant only.S. officinale var.lanceolatum contained no pyrrolizidine alkaloids but did contain isobauerenol. This feature points to an origin fromS. officinale.
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    Plant systematics and evolution 167 (1989), S. 149-164 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Cichorium intybus ; Tapetum ; pollen ; exine ; pollenkitt
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    Topics: Biology
    Notes: Abstract The tapetal development ofCichorium intybus L. is investigated using LM and TEM and discussed in relation to the development in other species. During the second meiotic division the tapetal cells become binucleate and lose their cell walls. They intrude the loculus at the time of microspore release from the meiotic callose walls, which means that a locular cavity is never present in this species. During pollen development they tightly junct the exine, especially near the tips of the spines. During the two-celled pollen grain stage they degenerate and most of their content turns into pollenkitt. Until anther dehiscence they keep their individuality, which means that these intruding tapetal cells never fuse to form a periplasmodium. The ultrastructural cytoplasmatic changes during this development are discussed in relation to possible functions.
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    Plant systematics and evolution 168 (1989), S. 59-69 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Fabaceae ; pigeonpea ; Cajanus cajan ; Sex allocation ; mating systems ; fruit and seed set
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Abstract Sex allocation theory predicts that: (1) resources allocated to androecium should decrease with an increase in selfing, (2) a decrease in androecium biomass should be accompanied by an increase in the biomass of pistils, and (3) a decrease in androecium biomass should be coupled with a decrease in flower size, specifically corolla biomass. Another predicted change in reproductive traits associated with variation in selfing concerns seed to ovule ratios, but does not directly stem from sex allocation theory. It has been postulated that seed to ovule ratios should be positively correlated with the amount of selfing. These predictions were tested for six accessions of pigeonpea,Cajanus cajan L., that differed in selfing rates. The results were remarkably in accordance with the predictions. We conclude that sex allocation theory provides a powerful tool to understand the evolution of many reproductive traits in plants.
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    Plant systematics and evolution 168 (1989), S. 87-94 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Apiaceae ; Pimpinella major ; P. saxifraga ; P. alpina ; Asteraceae ; Solidago virgaurea ; S. canadensis ; S. gigantea ; Exploratory data analysis (EDA) ; classification algorithm ; MOBCENTR
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    Notes: Abstract MOBCENTR is a classification algorithm combining features of classification about mobile centres, Ward algorithm and of the Hard-Isodata method. The results of this new algorithm and of Ward algorithm are compared by morphological characters of species ofSolidago andPimpinella.
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    Plant systematics and evolution 168 (1989), S. 181-193 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Ranunculaceae ; Adonis ; Taxonomy ; distribution ; cytology ; chromosome numbers ; meiosis
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    Topics: Biology
    Notes: Abstract The five annual species ofAdonis L., sect.Adonis, growing in Israel, form a series of diploid, tetraploid and hexaploid species. Their somatic chromosome numbers are 2n = 16 inA. annua L.,A. dentata Del. andA. palaestina Boiss., 2n = 32 inA. microcarpa DC., 2n = 48 inA. aestivalis L.; counts forA. dentata, A. palaestina andA. microcarpa are new records. There are indications that alloploidization may have been involved in the process of speciation in sect.Adonis. A taxonomic survey of the 8 species of the section reveals that a higher ploidy level is usually combined with a larger distribution area.
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    Molecular genetics and genomics 218 (1989), S. 531-535 
    ISSN: 1617-4623
    Keywords: Origin of replication ; Promoter ; Saccharomyces cerevisiae
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    Topics: Biology
    Notes: Summary In an attempt to devise a new assay for ARS-binding proteins we have inserted the HO ARS between the upstream activation site and the TATA region of the yeast CYC1 promoter. A marked reduction in promoter activity is observed. Inactivation of the HO ARS element by point mutation does not restore promoter activity to its original level, although a modest activation is seen. We have also inserted the HO ARS into the intron of the yeast actin gene; although there is no apparent deleterious effect on transcription, the activity of the ARS is abolished in this new environment.
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  • 99
    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; Heavy metal resistance ; DNA sequence ; Membrane
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    Notes: Summary A DNA fragment conferring resistance to zinc and cadmium ions in the yeast Saccharomyces cerevisiae was isolated from a library of yeast genomic DNA. Its nucleotide sequence revealed the presence of a single open reading frame (ORF; 1326 bp) having the potential to encode a protein of 442 amino acid residues (molecular mass of 48.3 kDa). A frameshift mutation introduced within the ORF abolished resistance to heavy metal ions, indicating the ORF is required for resistance. Therefore, we termed it the ZRC1 (zinc resistance conferring) gene. The deduced amino acid sequence of the gene product predicts a rather hydrophobic protein with six possible membrane-spanning regions. While multiple copies of the ZRC1 gene enable yeast cells to grow in the presence of 40 mM Zn2+, a level at which wild-type cells cannot survive, the disruption of the chromosomal ZRC1 locus, though not a lethal event, makes cells more sensitive to zinc ions than are wild-type cells.
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  • 100
    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; a-factor ; Conjugation ; G1 arrest ; ssl mutations
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    Topics: Biology
    Notes: Summary Nine independent mutants which are supersensitive (ssl −) to G1 arrest by the mating hormone a-factor were isolated by screening mutagenized Saccharomyces cerevisiae MATα cells on solid medium for increased growth inhibition with a-factor. These mutants carried lesions in two complementation groups, ssl1 and ssl2. Mutations at the ssl1 locus were mating type specific: MATα ssl1 − cells were supersensitive to α-factor but MATα ssl1 − were not supersensitive to α-factor. In contrast, mutations at the ssl2. locus conferred supersensitivity to the mating hormone of the opposite mating type on both MATα, and MATa cells. The α-cell specific capacity to inactivate externally added a-factor was shown to be lacking in MATα ssl1 − mutants whereas MATα ssl2. cells were able to inactivate a-factor. Complementation analysis showed that ssl2 and sst2, a mutation originally isolated as conferring supersensitivity to α-factor to MATa cells, are lesions in the same gene. The ssl1 gene was mapped 30.5 centi-Morgans distal to ilv5 on chromosome XII.
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