ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Angiosperms  (79)
  • evolution  (72)
  • Springer  (144)
  • American Meteorological Society
  • 1995-1999  (45)
  • 1990-1994  (99)
  • 1940-1944
  • 1998  (45)
  • 1990  (99)
  • 1941
Collection
Publisher
Years
  • 1995-1999  (45)
  • 1990-1994  (99)
  • 1940-1944
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 57 (1990), S. 143-150 
    ISSN: 1570-7458
    Keywords: Bruchidae ; Callosobruchus maculatus ; competition ; development ; evolution ; fecundity ; growth rates ; host preferences ; life tables ; mortality ; natural selection ; net reproductive rate ; oviposition traits
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Le taux partiel de reproduction nette (R inf0 sup* ) dépend de l'espèce de la plante sur laquelle les œufs sont pondus et du nombre de larves entrant dans la graine. La survie larvaire est réduite par 1/(le nombre de larves par graine) parce qu'une seule larve se développe dans une graine. La fécondité n'est pas modifiée par la compétition subie par les larves, la mortalité larvaire a l'effet le plus important sur R inf0 sup* . Les femelles éliminent ou réduisent la compétition larvaire en dispersant leurs œufs uniformément et font si peu d'erreurs avec une hyperdispersion que l'évolution d'un comportement plus précis n'accroîtrait R inf0 sup* que de 4% au maximum. Des femelles retournant à une distribution des œufs au hasard provoqueraient une réduction de R inf0 sup* de 25% au moins. Les légumineuses généralement cultivées dans l'Inde du Sud sont des hôtes acceptables quand elles sont présentées seules. Le choix des femelles entre 2 hôtes élève R inf0 sup* de 30% ou plus par rapport à une distribution au hasard. Les préférences les plus nettes concernent des combinaisons présentant la plus grande différence de R inf0 sup* . Les femelles qui hyperdispersent leurs œufs, choisissent leurs hôtes et évitent les pertes par compétition en empêchant que les œufs ne donnent plus de descendants que ne le ferait une ponte au hasard. Les particularités de la ponte sont variables et héritables. Les lignées se sélectionnent bien, en fonction de la dispersion de leurs œufs sur les graines, de la discrimination des plantes hôtes, et de la modulation de leur taux de ponte. La sélection naturelle maintient ces particularités du comportement d'une façon sédentaire.
    Notes: Abstract The deposition of eggs by this strain of Callosobruchus maculatus (Fab.) (Bruchidae: Coleoptera) departs from randomness in three ways; eggs are uniformly dispersed, oviposition rates drop when beans begin to carry 2 or more eggs, and there are sharp host preferences. Using random egg placement for the unspecialized condition, these traits are evaluated for their effect on a female's contributions of offspring to the next generation (R0, the net reproductive rate). The major increases in R0 result from females dispersing eggs so uniformly that larval competition is either reduced or eliminated. Females reduce their oviposition rate when the larva from an egg added to a bean is almost certain to die in competitive encounters. Host preferences and larval survival in a host are positively associated with the abundance of the host in South India. The three oviposition traits act together to give and R0 that is 25–50% than that of eggs placed at random. These traits are known to be variable and heritable, hence, the conditions necessary for natural selection are statisfied.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta biotheoretica 46 (1998), S. 141-156 
    ISSN: 1572-8358
    Keywords: locomotion ; Squamata ; lizards ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In lower quadrupedal vertebrates locomotor efficiency seems to result from the associate movements of the axial and appendicular systems, which are totally independent in structure and embryological origin. The curvature of the trunk, produced by a standing wave, magnifies the propulsive action of the limbs. In intermediate forms, the association of an elongate trunk with limbs reduced in size brings about functional consequences which may be noticeably diverse according to the degree of trunk elongation and limb reduction. According to environmental constraints, animals search for better locomotor efficiency, which implies the maintenance or breakage of this association of both locomotor systems. In some cases, limb action on the ground is added to the axial wave action through a perfect mutual adjustment of rhythmic activity, until mechanical inefficiency of the limbs is reached by possible loss of contact with the ground. In other cases, the limbs dragged on the ground during the stance phase act against the axial action or, on the contrary, are inhibited by the axial system. A review of available data tries to contribute to an understanding of the respective roles of both systems in the transition to limblessness.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 46 (1990), S. 1106-1117 
    ISSN: 1420-9071
    Keywords: Genetic code ; eucaryotic cell ; evolution ; code ambiguity ; code universality ; convergence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This article is a review of the rules used by eucaryotic cells to translate a nuclear messenger RNA into a polypeptide chain. The recent observation that these rules are not identical in two species of a same phylum indicates that they have changed during the course of evolution. Possible scenarios for such changes are presented.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    BioMetals 11 (1998), S. 277-295 
    ISSN: 1572-8773
    Keywords: evolution ; classification ; EF-hand ; domain ; homology ; chimera ; congruence ; gene duplication ; gene fusion ; eukaryote ; dendrogram ; calmodulin ; troponin C ; light chain of myosin ; S100 ; parvalbumin ; calcineurin ; recoverin ; calpain ; sorcin ; diacylglycerol ; calbindin ; aequorin ; phospholipase C ; BM-40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Forty-five distinct subfamilies of EF-hand proteins have been identified. They contain from two to eight EF-hands that are recognizable by amino acid sequence as being statistically similar to other EF-hand domains. All proteins within one subfamily are congruent to one another, i.e. the dendrogram computed from one of the EF-hand domains is similar, within statistical error, to the dendrogram computed from another(s) domain. Thirteen subfamilies - including Calmodulin, Troponin C, Essential light chain, Regulatory light chain - referred to collectively as CTER, are congruent with one another. They appear to have evolved from a single ur-domain by two cycles of gene duplication and fusion. The subfamilies of CTER subsequently evolved by gene duplications and speciations. The remaining 32 subfamilies do not show such general patterns of congruence; however, some - such as S100, intestinal calcium binding protein (calbindin 9kd), and trichohylin - do not form congruent clusters of subfamilies. Nearly all of the domains 1, 3, 5, and 7 are most similar to other ODD domains. Correspondingly the EVEN numbered domains of all 45 subfamilies most closely resemble EVEN domains of other subfamilies. Many sequence and chem-ical characteristics do not show systemic trends by subfamily or species of host organisms; such homoplasy is widespread. Eighteen of the subfamilies are heterochimeric; in addition to multiple EF-hands they contain domains of other evolutionary origins.© Kluwer Academic Publishers
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal for general philosophy of science 21 (1990), S. 231-257 
    ISSN: 1572-8587
    Keywords: basic rules ; change ; discipline-neutral ; evolution ; analogy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Philosophy , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Summary A small step is made in the direction of defining some general basic rules which can serve as a framework for research in several fields of the social sciences. The method of working with analogies asks for a more accurate approach. Starting from the concept of evolution in the form of a basic rule another basic rule is formulated. This rule shows what are the most important factors in long term developments and what types of development one can expect.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1570-7458
    Keywords: Cryptomyzus ; aphid ; hybridization ; host plant preference ; reproductive performance ; host-alternation ; speciation ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé C. galeopsidis Kaltenbach contient plusieurs formes qui ont différentes relations avec des plantes hôtes et des cycles distincts. Des croisements ont permis d'élucider la taxonomie de ces formes et d'étudier l'hérédité de préférences d'hôtes, des performances reproductives et de l'alternance d'hôtes. Une des formes apparaît comme une espèce distincte par suite de la valeur adaptative réduite des hybrides. Les autres formes avec alternance ou non des hôtes sont considérées comme conspécifiques et représentant deux stratégies vitales différentes. Les performances reproductives sont probablement polygéniques puisque les hybrides ont des performances intermédiaires. Les préférences d'hôtes des hybrides montrent certains degrés de dominance et semblent déterminées par quelques gènes seulement. L'alternance des hôtes est envisagée comme ayant une hérédité monofactorielle. Les conséquences sur la spéciation sont discutées.
    Notes: Abstract The aphid species Cryptomyzus galeopsidis (Kaltenbach) includes several distinct forms which have different host plant relationships and life cycles. Cross breeding was used to elucidate the taxonomic status of these forms and to investigate the inheritance of host preference, reproductive performance and host-alternation. One of the forms appeared to be a distinct species because of the reduced fitness of the hybrids. Other host-alternating and non host-alternating forms are considered conspecific and represent two life cycle strategies. Reproductive performance is probably controlled polygenically, since hybrids show an intermediate performance. Host preference in hybrids showed some degree of dominance and seemed to be determined by only a few genes. Host-alternation is presumed to be inherited monofactorially. The implications for speciation are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 46 (1990), S. 1117-1126 
    ISSN: 1420-9071
    Keywords: Genetic code ; mitochondria ; evolution ; organelles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The universal genetic code is used without changes in chloroplasts and in mitochondria of green plants. Non-plant mitochondria use codes that include changes from the universal code. Chloroplasts use 31 anticodons in translating the code; a number smaller than that used by bacteria, because chloroplasts have eliminated 10 CNN anticodons that are found in bacteria. Green plant mitochondria (mt) obtain some tRNAs from the cytosol, and genes for some other tRNAs have been acquired from chloroplast DNA. The code in non-plant mt differs from the universal code in the following usages found in various organisms: UGA for Trp, AUA for Met, AGR for Ser and stop, AAA for Asn, CUN for Thr, and possibly UAA for Tyr. CGN codons are not used byTorulopsis yeast mt. Non-plant mt, e.g. in vertebrates, may use a minimum of 22 anticodons for complete translation of mRNA sequences. The following possible causes are regarded as contributing to changes in the non-plant mt: directional mutation pressure, genomic economization, changes in charging specificity of tRNAs, loss of release factor RF2, changes in RF1, changes in anticodons, loss of lysidine-forming enzyme system, and disappearance of codons from coding sequences.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 46 (1990), S. 251-254 
    ISSN: 1420-9071
    Keywords: Bronchial tree ; evolution ; fractal ; lung airway ; morphogenesis ; renormalization group theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The mammalian lung exhibits features of a fractal tree: heterogeneity, self-similarity and the absence of a characteristic scale. The finite nature of the lung ultimately limits the range over which self-similarity scaling characteristics are applicable. However, generalization based on the scaling features of fractals, provides unique insight into geometric organization of anatomic structures. Furthermore, the mathematical theory of renormalization groups provides a description of the harmonically-modulated inverse power-law scaling observed for bronchial tree dimensions observed in different species. Compared to several mammalian species (dog, rat, hamster), the human lung shows marked differences in the phase of the harmonic modulation for both length and diameter measurements. These inter-species scaling differences suggest that evolutionary factors modify certain universal features of morphogenesis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Behavior genetics 20 (1990), S. 109-126 
    ISSN: 1573-3297
    Keywords: Y chromosome ; DNA ; mammals ; evolution ; behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract There is a predominant theory for the evolution of the mammalian Y chromosome. This theory hypothesizes that genes for sex determination and male-specific traits, as well as sequences for X-Y meiotic pairing, are conserved on the mammalian Y chromosome across all lineages and that all other Y chromosomal genes or sequences have been or will be lost in each mammalian lineage. There are effects of mouse Y chromosomal genes on behaviors and other traits that are not male specific. Under the predominant theory, these Y chromosomal genes could be the same as the conserved genes for sex determination or malespecific traits, or they could be genes that have been lost from the Y chromosomes of other mammalian lineages and that will eventually be lost from the Y chromosome of the rodent lineage. Recently, the evolution of the primate and rodent Y chromosomes has been studied at the DNA level. These studies are summarized and reviewed in this article. The findings of these studies are not fully consistent with the predominant theory for the evolution of the mammalian Y chromosome. Also, they imply that there are other possibilities for the phylogenetic history of Y chromosomal genes of mice with effects on behavior. These are that Y chromosomal genes with effects on mouse behaviors or other traits could be conserved genes other than those for sex determination or malespecific traits or that they could be novel genes on the Y chromosome of the rodent orMus lineage.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Biochemical genetics 28 (1990), S. 209-222 
    ISSN: 1573-4927
    Keywords: glycophorin A ; glycophorin B ; evolution ; primates ; chimpanzee ; gorilla ; orangutan ; gibbon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Analysis of nucleotide sequences of the human glycophorin A (GPA) and glycophorin B (GPB) genes has indicated that the GPA gene most closely resembles the ancestral gene, whereas the GPB gene likely arose from the GPA gene by homologous recombination. To study the evolution of the glycophorin gene family in the hominoid primates, restricted DNA on Southern blots from man, pygmy chimpanzee, common chimpanzee, gorilla, orangutan, and gibbon was probed with cDNA fragments encoding the human GPA and GPB coding and 3′-untranslated regions. This showed the presence in all of the hominoid primates of at least one GPA-like gene. In addition, at least one GPB-like gene was detected in man, both chimpanzee species, and gorilla, strongly suggesting that the event that produced the GPB gene occurred in the common ancestor of man-chimpanzee-gorilla. An unexpected finding in this study was the conservation ofEcoRI restriction sites relative to those of the other four enzymes used; the significance of this observation is unclear, but raises the question of nonrandomness ofEcoRI restriction sites in noncoding regions. Further analysis of the evolution of this multigene family, including nucleotide sequence analysis, will be useful in clarification of the evolutionary relationships of the hominoid primates, in correlation with the structure and function of the glycophorin molecules, and in assessment of the role of evolution in the autogenicity of glycophorin determinants.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Biochemical genetics 28 (1990), S. 337-346 
    ISSN: 1573-4927
    Keywords: glutamate dehydrogenase ; Drosophila melanogaster ; gene expression ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We have isolated theDrosophila melanogaster locus coding forl-glutamate dehydrogenase (EC 1.4.1.3) by virtue of its similarity to the corresponding human gene. There is only one copy of this gene in the fruit fly genome, located on the right arm of chromosome 3 (95D1-4). The transcript includes at least one large intron and matures to a ∼2.4-kb-long polyadenylated RNA whose expression is under developmental control.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    ISSN: 1573-4927
    Keywords: restriction fragment length polymorphisms ; glycophorin A ; glycophorin B ; MN blood group ; V-A-B-D blood group ; Vc antigen ; chimpanzee ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Twelve restriction fragment length polymorphisms (RFLPs) were detected in common chimpanzee using two restriction enzymes (HindIII andMspI) and four DNA probes to the coding regions of the human glycophorin A (GPA) and glycophorin B (GPB) genes and their 3′-untranslated regions. Seven RFLPs correlated with red cell expression of the Vc determinant of the MN blood group-related V-A-B-D system and five RFLPs correlated with nonexpression of this antigen. Animals heterozygous for theV allele that encodes the Vc determinant had all 12 polymorphic restriction fragments and appeared to show reduced intensity of probe hybridization to these fragments, consistent with the presence of aV and a non-V allele. No RFLPs were detected withEcoRI,SstI, orBamHI, in spite of the relatively large segment of DNA (at least 20 kb) involved in the polymorphisms. The RFLPs were chimpanzee specific and were not found in man, gorilla, orangutan, or gibbon. Multiple RFLPs distinguishing primate species are rare and may be useful markers for molecular evolution.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Biochemical genetics 28 (1990), S. 337-346 
    ISSN: 1573-4927
    Keywords: glutamate dehydrogenase ; Drosophila melanogaster ; gene expression ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We have isolated theDrosophila melanogaster locus coding forl-glutamate dehydrogenase (EC 1.4.1.3) by virtue of its similarity to the corresponding human gene. There is only one copy of this gene in the fruit fly genome, located on the right arm of chromosome 3 (95D1-4). The transcript includes at least one large intron and matures to a ∼2.4-kb-long polyadenylated RNA whose expression is under developmental control.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Behavior genetics 20 (1990), S. 563-568 
    ISSN: 1573-3297
    Keywords: personality ; fertility ; family size ; fitness ; extraversion ; neuroticism ; impulsivity ; genetic architecture ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract The relationship between reproductive success (number of biological children) and personality was explored in 1101 postmenopausal females from the Australian twin registry. The quadratic response surface relating fitness to extraversion (E) and neuroticism (N) showed a saddle point at intermediate levels of E and N. Selection was shown to be stabilizing, i.e.,having an intermediate optimum, along the axis low E, low N-high E, high N and more mildly disruptive, having greater fitness in the extremes, along the axis low N, high E-high N, low E. Neither dimension of personality considered by itself showed a significant linear or quadratic relationship to reproductive success. Sections through the fitness surface, however, show selection tends to favor high neuroticism levels in introverts and low neuroticism levels in extroverts.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Plant cell reports 18 (1998), S. 143-147 
    ISSN: 1432-203X
    Keywords: Key wordsNicotiana tabacum ; Male germ unit ; Scanning electron microscopy ; Sperm isolation ; Angiosperms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sperm cells are released from pollen tubes of tobacco as linked cells, associated with the vegetative nucleus in an assemblage known as the male germ unit (MGU). Using light microscopy, the MGU assemblage appears to be ensheathed by cytoplasmic material of the pollen tube, which may stabilize their association. Following their release, the shape of the sperm cells and vegetative nucleus changes from an ellipsoidal to a more spheroidal morphology. When most of the cytoplasmic material is dispersed, a boundary remains around the two sperm cells. Using scanning electron microscopy, the cytoplasmic material surrounding the MGU appears filamentous, sometimes twisted and rope-like. Based on these observations, the function of the MGU of tobacco is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    ISSN: 1615-6110
    Keywords: Angiosperms ; Liliaceae ; Asphodelus tenuifolius ; A. fistulosus ; Cytogenetics ; electrophoretics ; morphology ; duplication genes ; speciation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The biological analysis of six populations ofAsphodelus tenuifolius and 12 populations ofA. fistulosus has confirmed that they are separate species. Both their floral structures (length of the tepals, stamens, anthers and style) and also their pollen size are clearly different.A. tenuifolius has only the 2n = 28 chromosome race, whileA. fistulosus has 2n = 28 and 2n = 56.A. tenuifolius is genetically less variable thanA. fistulosus and they have different electrophoretic mobilities. Gene duplication phenomena exist in the 2n = 28 level of both species.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 169 (1990), S. 41-54 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Abutilon theophrasti ; Datura stramonium ; Panicum miliaceum ; Sorghum halepense ; Setaria faberi ; Weeds ; allozymes ; life history ; variation ; Flora of N. America
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationships of allozyme and life history variation in a particularly narrow ecological setting are studied. Levels of genetic variation are compared in five introduced, predominantly selfing weedy species that are undergoing rapid range expansion northward in eastern N. America, mostly in monocultures of soybean and maize. In all of these species, a low level of allozyme variation contrasts sharply with the substantial inter- and intrapopulational variation in morphological and phenological life history features. Evolutionary and historical factors, determining variability of the species examined are reviewed, including founder effects, breeding system, environmental homogeneity, polyploidy, domestication, and crop-weed interactions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    ISSN: 1615-6110
    Keywords: Angiosperms ; Boraginaceae ; Symphytum tuberosum complex ; S. grandiflorum agg ; Chemotaxonomy ; pyrrolizidine alkaloids ; triterpenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract InS. tuberosum subspp.tuberosum andnodosum, S. grandiflorum andS. ibericum the presence of the pyrrolizidine alkaloids lycopsamine, echimidine and symphytine could be demonstrated. The taxonS. tuberosum contains an unknown compound that seems to be specific for this taxon. This compound is not the pyrrolizidine alkaloid anadoline which has previously been reported for this species. It is possibly represented by a peak on GC/MS with a molecular ion peak at m/z 623 (as TMS derivative) and can be used as a chemotaxonomic marker for the speciesS. tuberosum. The pyrrolizidine alkaloid pattern of the two subspecies ofS. tuberosum reinforces the close relationship. Fresh material ofS. tuberosum contained the triterpene isobauerenol, but in herbarium material isobauerenol was lacking. InS. grandiflorum, neither fresh nor dried material contains isobauerenol. In herbarium material ofS. ibericum also no isobauerenol could be found. More extensive chemotaxonomical research is necessary to support the view thatS. abchasicum is more closely related toS. ibericum than toS. grandiflorum.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 169 (1990), S. 97-110 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteraceae ; Compositae ; Inuleae ; Antennaria ; A. rosea ; Agamic complex ; agamospermy ; asexual reproduction ; clonal organism ; dioecy ; morphology ; numerical taxonomy ; phenetics ; polyploidy ; systematics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract TheAntennaria rosea polyploid agamic complex is one of the most morphologically diverse and widespread complexes of N. AmericanAntennaria. The group is taxonomically confusing because of numerous agamospermous microspecies, having been recognized as distinct species. Morphometric analyses have demonstrated that the primary source of morphological variability in the complex derives from six sexually reproducing progenitors,A. aromatica, A. corymbosa, A. media, A. microphylla, A. racemona, andA. umbrinella. Additionally, two other sexually reproducing species,A. marginata andA. rosulata, may have contributed to the genetic complexity of theA. rosea complex. Cluster analysis indicates that four discrete morphological groups exist within theA. rosea complex. Each group could be the result of predominance of genes from different groups of sexual progenitors. AsA. rosea is of multiple hybrid origin, from among several sexual progenitors, it is advisable to recognizeA. rosea as a distinct species from its sexual progenitors.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteraceae ; Inuleae ; Antennaria ; Geographic variation ; clinal variation ; principal component analysis ; correlation coefficients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Patterns of intraspecific variation were examined inAntennaria alborosea A. E. Porsild,A. corymbosa E. Nels,A. marginata Greene,A. microphylla Rydb.,A. parvifolia Nutt., andA. umbrinella Rydb. AlthoughA. alborosea was initially considered arctic in distribution, it became apparent that a southern montane element also exists. Our results suggest that morphological differences between arctic and southern montane specimens represent clinal variation. The additional morphological data for specimens that occur more than 1,500 km south of the species' range as it was initially described result in a better understanding of this once presumed arctic taxon. Morphological variation in the dioecious speciesA. corymbosa, A. marginata, A. microphylla, A. parvifolia, andA. umbrinella was greater between the genders than was geographic variation within each gender. These results demonstrate that both pistillate and staminate specimens must be examined in dioecious species ofAntennaria if morphological variation in the respective species is to be fully understood. Character size or number of broadly distributed species (A. microphylla andA. parvifolia) generally decreased with increasing longitude, whereas characters of species with more restricted distributions (A. alborosea, A. corymbosa, andA. marginata) generally increased in size or number with increasing latitude or longitude.Antennaria umbrinella was an exception in this respect.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 169 (1990), S. 25-29 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Oxalidaceae ; Oxalis tuberosa alliance ; Chromosome numbers ; karyotype analyses ; cytotaxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Twelve taxa of theOxalis tuberosa alliance were analysed and found to share the same basic chromosome number x = 8. The karyotypes are composed by small metacentric and submetacentric chromosomes. Different ploidy levels were found among the taxa: there were 9 diploids, 1 tetraploid, 1 hexaploid and 1 octoploid. The last ploidy level corresponds toO. tuberosa, the only tuber bearing taxon found so far in the alliance. Cytotaxonomic evidence and evolutionary considerations suggest to classify theO. tuberosa alliance in sect.Herrerea.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 169 (1990), S. 65-68 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Boraginaceae ; Onosma gigantea ; Trichodesma africana ; Trichodesma boissieri ; Buzz-pollination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Buzz-pollination was observed in three nectariferousBoraginaceae spp.:Onosma gigantea Lam.,Trichodesma africana (L.)R. Br. andT. boissieri Post. An evolutionary pathway from usual nectariferous flowers to typical buzz-pollinated flowers is suggested.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 169 (1990), S. 81-96 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Gramineae ; Festuceae ; Dactylis glomerata ; Enzymatic markers ; phenology ; interploid exchanges ; autopolyploidy ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phylogenetic relationships between sympatric, morphologically indistinguishable diploid and tetraploid plants ofDactylis glomerata L. (Gramineae) in Galicia (Spain) were assessed using allozyme markers for 6 distinct systems. The study exploited recent introduction in Galicia and subsequent hybridization of an alien 4xDactylis subspecies possessing distinct allozymes from those of all the native plants. Opportunities for gene exchanges between the ploidies were estimated from in situ observations of flowering, examination of progenies in 2x/4x natural and experimental crosses, and enzyme analyses. Results show a high genetic similarity between the Galician diploids and tetraploids, which possess peculiar alleles in common. Although the ploidy levels usually have distinct flowering periods, interploidal crosses do occasionally occur. Gene flow is likely much more important from the diploid to the tetraploid level. A good genetic intermixing occurs between the Galician and the alien tetraploid entities which have simultaneous flowering. Autopolyploidization of the diploids followed by various rates of hybridization is proposed as one very probable origin of natural tetraploids inDactylis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteraceae ; Inuleae ; Antennaria alborosea ; A. corymbosa ; A. marginata ; A. microphylla ; A. parvifolia ; A. rosea ; A. umbrinella ; Taxonomy ; multivariate morphometrics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Multivariate analysis of vegetative and reproductive characters was used to examine morphological relatedness amongAntennaria alborosea A. E. Porsild,A. corymbosa E. Nels.,A. marginata Greene,A. microphylla Rydb.,A. parvifolia Nutt.,A. rosea Greene, andA. umbrinella Rydb. Both pistillate and staminate plants were examined. Some of the characters examined were variable in one species, but stable in another (i.e., presence or absence of papillae on the achenes). Our analyses indicate that the seven species are morphologically distinct. It is hypothesized that theA. rosea agamic complex arose through hybridization amongA. corymbosa, A. microphylla, A. umbrinella, and possiblyA. dioica (L.)Gaertn. However, hybridization between the three former species and others, as well as their subsequent morphological responses to different environmental conditions causes confusion in recognizing the taxa.Antennaria angustifolia Rydb.,A. arida E. Nels.,A. confinis Greene,A. scariosa E. Nels.,A. foliacea humilis Rydb.,A. concinna E. Nels., andA. viscidula E. Nels. are considered to represent F 1 hybrids.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 170 (1990), S. 37-51 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Valerianaceae ; Transfer cells ; lignification ; lipid droplets ; oil cells ; tannins ; Development ; structure ; axial distribution ; transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Development, structure and the axial distribution of transfer cells and their lignification were investigated inValerianella locusta, Valeriana officinalis, andV. tuberosa (Valerianaceae). Fundamental new results are: (1) Transfer cells often contain numerous lipid droplets. Within the stem the distribution of cells containing lipid droplets correlates to that of transfer cells. (2) InValeriana officinalis persisting protuberances are frequently found on pit membranes of xylem transfer cells. Lignified transfer cells can undergo a second modification: a layer covering the secondary wall forms wall ingrowths similar to those of transfer cells. (3) Peripheral pith cells, abuting transfer cells, are able to modify into transfer cells. Cambial derivatives are only temporarily developed as transfer cells. (4) Phloem transfer cells are found in vascular bundles of the whole axis. (5) In roots, xylem transfer cells are poorly developed or absent. (6) Oil cells with oil bodies are present in the rape ofValeriana tuberosa. They are absent however in the stem of the species investigated. (7) Tannins occur in elements of the primary cortex, phloem and secondary xylem ofValeriana officinalis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 169 (1990), S. 237-243 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteraceae ; Heliantheae ; Ambrosia ; Anther ; crystals ; pollen ; sperm cells ; tapetum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Staminate flowers of giant ragweed,Ambrosia trifida L. (Asteraceae, tribeHeliantheae, subtribeAmbrosiinae) were processed into resin and sectioned 1–2 µm thick. The invasive (amoeboid) anther tapetum remains parietal until microspores are released from tetrads, then it swells and invades the locule, merging gradually into a single protoplast that flows among the microspores. After the tapetal membrane ruptures at late microspore stage, tapetal debris fills the locule, then disappears as pollen matures. Pollen becomes tricelled before anthesis. The two sperm cell nuclei are slender and wormlike. The present report supports the two generalizations that invasive tapetum and tricelled pollen are attributes of theAsteraceae.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 170 (1990), S. 205-214 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Polemoniaceae ; Pollen ; ovule ratio ; stigmatic pollen germination ; breeding systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pollen — ovule ratios and percentages of stigmatic pollen germination (SPG) were measured for over 160 taxa of thePolemoniaceae. When related to taxa with known breeding systems, it is found that low SPGs and high P:O ratios characterize xenogamous plants, high SPGs and low P:Os characterize autogamous plants. There is a significant negative correlation between P:O ratio and SPG in the whole family as well as in certain genera. Both measures can serve as reliable indicators of the breeding systems in taxa of thePolemoniaceae and can be measured in dried or living specimens. Accordingly, most polemons feature “mixed” breeding system, i.e. facultative xenogamy or facultative autogamy. Xenogamy is common among the tropical genera and in theLeptodactylon, Phlox andPolemonium. Autogamy is more frequent in the tribeGilieae (particularly inGilia) than in the other tribes. Annual taxa tend to be autogamous, showing on the average higher SPG and lower P:O ratio. The lepidopteran-pollinated group of species have a higher mean P:O ratio and lower mean SPG thus indicating that such plants are associated with crosspollination more than the others.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Eupatorium ; Chromosomal distance ; chromosomal identity ; karyotype analysis ; statistics phenetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Somatic metaphase karyotypes were analyzed for 22 diploid species ofEupatorium. The karyotypic comparisons were made using two indices: minimal chromosomal distance (MCD), measuring overall dissimilarities, and chromosomal identity (CI), measuring number of morphologically identical chromosomes between species. The resulting phenograms from these indices are largely compatible. The 22 species cluster into four groups in the phenogram using MCD, and the grouping corresponds well with morphology or geographic distribution into the three N. American groupsEutrochium, Uncasia, Traganthes, and the E. Asian group. These results suggest that karyotypes in perennialEupatorium have been considerably conservative and changed not through large chromosomal mutations but through small chromosomal mutations gradually fixed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    ISSN: 1615-6110
    Keywords: Angiosperms ; Scrophulariaceae ; Striga hermonthica ; Hemiparasitism ; hostspecificity ; enzyme electrophoresis ; genetic diversity ; Flora of Burkina Faso ; Sudan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Striga hermonthica is a root hemiparasite that attacks onlyGramineae, includingSorghum and millet for which it is a principal cause of lowered yield. Enzyme electrophoresis was used to investigate genetic diversity inStriga hermonthica and to determine the level of differentiation between host-specialized populations. Nine genetic loci coding eight enzymes were interpreted and data obtained from three populations: oneSorghum-adapted population from Sudan and two populations from Burkina Faso, oneSorghum-adapted and the other millet-adapted. Levels of polymorphism were similarly high in all three populations (P=0.625, A=2.6−2.8, H=0.293−0.401). Genotypic frequencies at most loci conformed to Hardy-Weinberg expectations in each population, consistent with outcrossing as predicted from previous studies of floral biology. Occasional heterozygote deficiencies were probably the result of Wahlund effect. The mean value of FST over the three populations was 0.068, indicating a slight to moderate level of genetic differentiation among the populations. The two Burkina Faso populations were more closely related (S=0.940, D=0.006) than either was to the Sudan population, suggesting that geographic separation is more important than host specialization in contributing to population differentiation. TheSorghum-adapted population was slightly closer to the Burkina FasoSorghum-adapted population (S=0.873, D=0.047) than to Burkina Faso millet-adapted population (S=0.851, D=0.074). The absence of substantial genetic divergence between host-specific populations ofStriga could result either from recent evolution of host-specialized strains or from strong selection for physiological specialization in the face of substantial gene flow between the populations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 210 (1998), S. 57-86 
    ISSN: 1615-6110
    Keywords: Alliaceae ; Allium ; Nuclear DNA amount ; adaptation ; evolution ; infrageneric classification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The 4C DNA amounts of 86 species fromAllium subgg.Allium, Rhizirideum, Bromatorrhiza, Melanocrommyum, Caloscordum andAmerallium show a 8.35-fold difference ranging from 35.60 pg (A. ledebourianum, 2n = 16) to 297.13 pg (A. validum 2n = 56). At diploid level the difference is 3.57-fold betweenA. ledebourianum (35.60 pg) andA. ursinum (127.14 pg). This shows that a significant loss and/or gain of DNA has occurred during evolution. On average subgg.Rhizirideum andAllium have less DNA amount than subgg.Melanocrommyum andAmerallium. The distribution of nuclear DNA amounts does not show discontinuous pattern and regular groups. The evolution of genome size has been discussed in relation to polyploidy and genomes, heterochromatin, adaptive changes in morphological characteristics, phenology and ecological factors, and infrageneric classification.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    ISSN: 1573-5125
    Keywords: microcrustaceans ; Daphnia ; evolution ; interspecific hybridization ; molecular systematics ; aquatic ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cladoceran crustaceans are an important component of zooplankton in a wide range of freshwater habitats. Although the ecological characteristics of several cladoceran species have been well studied, biogeographical studies have been hampered by problematic taxonomic affiliations. However, recently developed molecular techniques, provide a powerful tool to subject aquatic taxa to comparative analyses. Here we highlight recent molecular approaches in aquatic ecology by presenting a simple method of DNA preparation and PCR amplification of the mitochondrial DNA (16S rDNA) in species from nine different families within the cladocera. On a broad taxonomic scale, sequence analysis of this mtDNA fragment has been used to produce the first molecular based phylogeny of the cladocera. This analysis clustered the cladoceran families in a fashion similar to that suggested by previous systematic classifications. In a more detailed analysis of the family Daphniidae, nuclear randomly amplified polymorphic DNA (RAPD), mitochondrial restriction fragment length polymorphism (RFLP) and morphological analyses were combined to identify species and interspecific hybrids within the Daphnia galeata species complex across 50 lakes in 13 European countries and one lake in Africa. The study revealed interspecific hybridization and backcrossing between some taxa (D. cucullata and D. galeata) to be widespread, and species and hybrids to frequently occur in sympatry. Genetic, as well as morphological information, suggests the occurrence of D. hyalina outside the Holarctic.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 5 (1990), S. 3-36 
    ISSN: 1572-8404
    Keywords: Material models ; semantic view of theories ; natural history ; ecology ; evolution ; museums ; Joseph Grinnell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Accounts of the relation between theories and models in biology concentrate on mathematical models. In this paper I consider the dual role of models as representations of natural systems and as a material basis for theorizing. In order to explicate the dual role, I develop the concept of a remnant model, a material entity made from parts of the natural system(s) under study. I present a case study of an important but neglected naturalist, Joseph Grinnell, to illustrate the extent to which mundane practices in a museum setting constitute theorizing. I speculate that historical and sociological analyses of institutions can play a specific role in the philosophical analysis of model-building strategies.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 5 (1990), S. 149-173 
    ISSN: 1572-8404
    Keywords: Darwinian ethics ; ethics ; evolution ; evolutionary ethics ; M. Ruse ; naturalistic fallacy ; sociobiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Michael Ruse has proposed in his recent book Taking Darwin Seriously and elsewhere a new Darwinian ethics distinct from traditional evolutionary ethics, one that avoids the latter's inadequate accounts of the nature of morality and its failed attempts to provide a naturalistic justification of morality. Ruse argues for a sociobiologically based account of moral sentiments, and an evolutionary based casual explanation of their function, rejecting the possibility of ultimate ethical justification. We find that Ruse's proposal distorts, overextends and weakens both Darwinism and naturalism. So we propose an alternative Darwinian metaethics that both remedies the problems in Ruse's proposal and shows how a Darwinian naturalistic account of the moral good in terms of human fitness avoids the naturalistic fallacy and can provide genuine, even if limited, justifications for substantive ethical claims. Thus, we propose to really take Darwin seriously.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 5 (1990), S. 451-457 
    ISSN: 1572-8404
    Keywords: Auschwitz ; biology ; ethics ; evolution ; moral theory ; naturalistic fallacy ; Richards
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Conclusion Richards's theory, then, fails on three counts. By illegitimately importing a premise from outside of the theory of evolution in order to construct a valid argument, Richards has failed to achieve his objective of deriving a moral theory exclusively from biological facts. By sliding from a causal use of “ought” to a moral one, Richards commits the fallacy of ambiguity. And by insisting that action from the motive of altruism is moral while claiming that an ethical theory which justifies Hitler's camps must be judged false, Richards has falsified his own ethical theory.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 13 (1998), S. 443-470 
    ISSN: 1572-8404
    Keywords: Buffon ; Darwin ; Gayon ; species ; individuality ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Gayon's recent claim that Buffon developed a concept of species as physical individuals is critically examined and rejected. Also critically examined and rejected is Gayon's more central thesis that as a consequence of his analysis of Buffon's species concept, and also of Darwin's species concept, it is clear that modern evolutionary theory does not require species to be physical individuals. While I agree with Gayon's conclusion that modern evolutionary theory does not require species to be physical individuals, I disagree with his reasons and instead provide logical rather than historical reasons for the same conclusion.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 13 (1998), S. 255-261 
    ISSN: 1572-8404
    Keywords: evolution ; speciation ; levels of selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Biologists often define evolution as a change in allele frequencies. Consideration of the evolution of the pocket mouse will show that it is possible to have evolution without any change in the allele frequencies in a population (through change in the genotype frequencies). The implications of this for genic selectionism are then discussed. Sober and Lewontin (1982) have constructed an example to demonstrate the “blindness” of genic selectionism in certain cases. Sterelny and Kitcher (1988) offer a defense against these arguments which assumes a conventionalist approach to populations. The example considered here will be shown to offer a more plausible and far-reaching argument against the view that alleles can always be seen as the units of selection.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 13 (1998), S. 233-244 
    ISSN: 1572-8404
    Keywords: reference ; meaning ; individual ; class ; definition ; clade ; evolution ; phylogeny ; phylogenetic taxonomy ; systematics ; tree-thinking ; cladistics ; intention ; extension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Although naming biological clades is a major activity in taxonomy, little attention has been paid to what these names actually refer to. In philosophy, definite descriptions have long been considered equivalent to the meaning of names and biological taxonomy is a scientific application of these ideas. One problem with definite descriptions as the meanings of names is that the name will refer to whatever fits the description rather than the intended individual (clade). Recent proposals for explicit phylogenetic definitions of clade names suffer from similar problems and we argue that clade names cannot be defined since they lack intension. Furthermore we stress the importance of “tree-thinking” for phylogenetic reference to work properly.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 13 (1998), S. 187-204 
    ISSN: 1572-8404
    Keywords: evolution ; meme ; gene ; morality ; culture ; psychological predisposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Dennett (1995) argues that memes or cultural replicators are largely autonomous of genes, and that they are fairly efficacious in determining who we are and what we do. I argue that Dennett's arguments are wrong in several aspects, which we can see by analyzing processes at appropriate levels. Specifically, I argue that it is not true that we as persons are created largely by memes, that our memes are not largely independent of our genes, and that we can use the universality of memes to make inferences about genetic predispositions. Finally, by suggesting an innate psychological mechanism for morality, I argue that morality may be largely the effect of genetic predispositions rather than autonomous.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 13 (1998), S. 359-391 
    ISSN: 1572-8404
    Keywords: adaptation ; algorithm ; atavism ; contingency ; deep homology ; Dennett ; development ; disparity ; epicurean selectionism ; evolution ; exaptation ; Gould ; metaphors ; punctuated equilibrium ; selectionism ; spandrels
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract In his recent book on Darwinism, Daniel Dennett has offered up a species of a priori selectionism that he calls algorithmic. He used this view to challenge a number of positions advocated by Stephen J. Gould. I examine his algorithmic conception, review his unqualified enthusiasm for the a priori selectionist position, challenge Dennett's main metaphors (cranes vs. skyhooks and a design space), examine ways in which his position has lead him to misunderstand or misrepresent Gould (spandrels, exaptation, punctuated equilibrium, contingency and disparity), and discuss recent results in developmental biology that suggest that an a priori position does not fill the demands of an evolutionary biology. I conclude by insisting that evolutionary biology is many leveled, complicated, and is carried on an ever shifting and expanding empirical base that when disregarded results in caricature.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    ISSN: 1573-5125
    Keywords: ecomorphology ; evolution ; feeding ; fish stocks ; major histocompatibility complex ; molecular genetics ; species flock
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A unique species flock of large barbs (Barbus spp.) from Lake Tana is presented, from the level of fish stocks to molecules. Evidence is given for the species status of 14 morphotypes of large barbs. They distinctly differ in: (1) head and body morphometrics, (2) food preferences, (3) distribution patterns, (4) maximal body size, (5) spawning area and period, and (6) molecular genetic characters. Most types show early morphological divergence at small size. Major Histocompatibility Complex (MHC) genes, encoding cell membrane proteins involved in defence against pathogens, were found to be diagnostic for the species' genetic identity. A strong selective pressure on particular amino acid positions in the MHC protein sequence most probably arose in response to different pathogen loads from the newly invaded ecological niches after formation of Lake Tana, ca. two million years ago. Arguments for a sympatric origin of this species flock are discussed. An evolutionary scenario suggests a riverine ancestral Barbus intermedius invading Lake Tana after its formation by volcanic blocking of the Blue Nile river and its isolation by waterfalls. Specialisation for particular food types and disruptive selection on many feeding structures are hypothesized as the evolutionary drive in speciation. The causal relationship between the diversity in feeding structures and food types is explained from experiments and models. As an example, the potential food niche of three barb species is predicted from parameter values measured from a large set of feeding structures and tested against the actual gut contents. The co-occurrence of eight piscivorous barb species is unique for cyprinid fish, which lack oral jaw teeth and a stomach. The significance of this aquatic ecosystem as a multidisciplinary evolutionary laboratory and the need for a wise balance between exploitation and conservation is stressed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical geology 22 (1990), S. 95-106 
    ISSN: 1573-8868
    Keywords: evolution ; extinction ; macroevolution ; probability ; species longevity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract The longevities of species constituting a statistical population have an underlying distribution whose form and parametric values reflect probabilities of origination and extinction through time. In the case that a part of the population is extant, the form of distribution and its parameters cannot be estimated directly from the longevity data without bias. Longevities of extant “censored” species are truncated and thus do not statistically represent the underlying distribution. The remaining “uncensored” species do not represent the true relative abundances of longevities. These biases can be defined from the probability densities for species longevitys and intervalr between successive originations of species. For realistic densities ofs andr, species with an intermediate longevity are preferentially censored. This simple, general result arises because the probability of censoring a species increases with its longevity, whereas the probability of censoring a given longevity varies with its relative abundance.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Electronic Resource
    Electronic Resource
    Springer
    Autonomous agents and multi-agent systems 1 (1998), S. 59-88 
    ISSN: 1573-7454
    Keywords: agents ; evolution ; information filtering ; world wide web
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Amalthaea is an evolving, multi-agent ecosystem for personalized filtering, discovery, and monitoring of information sites. Amalthaea's primary application domain is the World Wide Web and its main purpose is to assist its users in finding interesting information. Two different categories of agents are introduced in the system: filtering agents that model and monitor the interests of the user and discovery agents that model the information sources.A market-like ecosystem where the agents evolve, compete, and collaborate is presented: agents that are useful to the user or other agents reproduce, while low-performing agents are destroyed. Results from various experiments with different system configurations and varying ratios of user interests versus agents in the system are presented. Finally issues like fine-tuning the initial parameters of the system and establishing and maintaining equilibria in the ecosystem are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 36 (1998), S. 285-295 
    ISSN: 1573-5028
    Keywords: Chlamydomonas eugametos ; evolution ; genome sequence ; green algae ; group I introns ; mitochondrial DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The complete nucleotide sequence of the Chlamydomonas eugametos (Chlamydomonadales, Chlorophyceae, sensu Mattox and Stewart) mitochondrial genome has been determined (22 897 bp, 34.6% G + C). The genes identified in this circular-mapping genome include those for apocytochrome b, subunit 1 of the cytochrome oxidase complex, subunits 1, 2, 4, 5, and 6 of the NADH dehydrogenase complex, discontinuous large and small subunit ribosomal rRNAs and three tRNAs whose anticodons CAU, CCA and UUG are specific for methionine, tryptophan and glutamine, respectively. The C. eugametos mitochondrial DNA (mtDNA), therefore, shares almost the same reduced set of coding functions and similar unusual features of rRNA gene organization with the linear 15.8 kb mtDNA of Chlamydomonas reinhardtii, the only other completely sequenced chlamydomonadalean mtDNA. However, sequence analysis of the C. eugametos mtDNA has revealed the following distinguishing features relative to those of C. reinhardtii: (1) the absence of a reverse transcriptase-like gene homologue, (2) the presence of an additional gene for tRNAmet that may be a pseudogene, (3) a completely different gene order, (4) transcription of all genes from the same mtDNA strand, (5) a lower G + C content, (6) less pronounced bias in codon usage, and (7) nine group I introns, several of which contain open reading frames coding for potential maturases/endonucleases and two have a nucleotide at the 5′ or 3′ splice site of the deduced precursor RNAs that deviates from highly conserved nucleotides reported in other group I introns. The features of mitochondrial genome organization and gene content shared by C. eugametos and C. reinhardtii contrast with those of other green algal mtDNAs that have been characterized in detail. The deep evolutionary divergence between these two Chlamydomonas taxa within the Chlamydomonadales suggests that their shared features of mitochondrial genome organization evolved prior to the origin of this group.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Electronic Resource
    Electronic Resource
    Springer
    Evolutionary ecology 12 (1998), S. 153-164 
    ISSN: 1573-8477
    Keywords: algae ; anti-predator adaptations ; arms race ; Chlorella vulgaris ; chrysophytes ; continuous culture ; evolution ; flagellates ; multicellularity ; Ochromonas vallescia ; phagocyte ; predator–prey interactions ; selective pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Predation was a powerful selective force promoting increased morphological complexity in a unicellular prey held in constant environmental conditions. The green alga, Chlorella vulgaris, is a well-studied eukaryote, which has retained its normal unicellular form in cultures in our laboratories for thousands of generations. For the experiments reported here, steady-state unicellular C. vulgaris continuous cultures were inoculated with the predator Ochromonas vallescia, a phagotrophic flagellated protist (‘flagellate’). Within less than 100 generations of the prey, a multicellular Chlorella growth form became dominant in the culture (subsequently repeated in other cultures). The prey Chlorella first formed globose clusters of tens to hundreds of cells. After about 10–20 generations in the presence of the phagotroph, eight-celled colonies predominated. These colonies retained the eight-celled form indefinitely in continuous culture and when plated onto agar. These self-replicating, stable colonies were virtually immune to predation by the flagellate, but small enough that each Chlorella cell was exposed directly to the nutrient medium.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Springer
    Evolutionary ecology 12 (1998), S. 245-250 
    ISSN: 1573-8477
    Keywords: environmental sex determination ; evolution ; nest-site philopatry ; reptiles ; sex ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The reason for the frequent occurrence of environmental sex determination (ESD) in reptiles is still not well understood, although much effort has been devoted to solving the issue. Stimulated by the occurrence of nest-site philopatry in some species, this paper examines a diploid model of the influence of nest-site philopatry on the evolution of ESD. Analysis shows that nest-site philopatry can lead to ESD because the fitnesses of sons and daughters are not influenced in the same way by nest-site quality. Daughters inherit the nest site and thus benefit more than sons from a high-quality nest site. Conversely, the fitness of daughters at low-quality nest sites is lower compared to the fitness of sons. Therefore, genes causing ESD can spread by causing the production of more sons at low-quality nest sites and more daughters at high-quality nest sites. Suggestions are made to test empirically whether nest-site philopatry led to the evolution of ESD.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 169 (1990), S. 209-217 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Silybum marianum ; Formicidae ; Messor semirufus ; Myrmecochory ; preadaptations ; synanthropic plant ; grasslands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The common Mediterranean ruderal thistleSilybum marianum is associated with nutrient-rich sites. Its wind-dispersed achenes possess an oily food body, that is attractive to harvester-ants. Following removal of the oily body, the achenes are deposited in the refuse zone together with rich organic material and soil removed from the nest; while in the nest the achenes are partly protected from fires. The thistle grows successfully in the nutrient-enriched refuse zone and thus dominates patches in the grassland. Preadaptations to live in association with harvester-ants enableS. marianum to occur also on marking stations of male gazelle, on cattle dung deposits, and in synanthropic ruderal habitats.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 169 (1990), S. 219-235 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Acanthaceae ; Justicia ; Siphonoglossa ; Cytology ; flavonoids ; systematics ; taxonomy ; generic relationships
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The transfer of the four taxa ofSiphonoglossa sect.Pentaloba toJusticia is proposed. It is shown that the taxa of this section were placed inSiphonoglossa primarily because of a single-character phenetic relationship and that they correctly belong inJusticia. In addition to morphology, data from cytology and flavonoid chemistry are also presented that support this intergeneric transfer. A key to the taxa and a detailed taxonomic treatment of the section are provided.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 169 (1990), S. 245-259 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Potamogetonaceae ; Potamogeton distinctus ; P. indicus ; P. nodosus ; P. tepperi ; Taxonomy ; distribution ; description
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Potamogeton distinctus has an E. Asian distribution and is closely related toP. nodosus. P. tepperi seems to be a synonym ofP. tricarinatus, even though the name has frequently been applied to other species likeP. distinctus. P. indicus is a synonym ofP. nodosus notwithstanding the fact that not all Indian broad-leaved pondweeds belong to that taxon.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 170 (1990), S. 29-35 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Balanophoraceae ; Balanophora ; Hachettea ; Langsdorffia ; Lophophytum ; Scybalium ; Thonningia ; Stomata ; epidermal surface
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Both adaxial and abaxial leaf surfaces were searched for stomata inBalanophora elongata, B. fungosa, Hachettea austro-caledonica, Langsdorffia hypogaea, Lophophytum mirabile subsp.mirabile, Scybalium jamaicense, andThonningia sanguinea (Balanophoraceae). Neither stomata nor guard cells were observed. The epidermal surfaces of these species are extremely diverse with respect to cell shape, cell size, and surface ornamentation, these features providing valuable systematic criteria.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteraceae ; Taraxacum sect.Ruderalia ; Sexual diploids ; mixed populations ; distribution pattern ; ecogeographical relations ; taxonomical problems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Herbarium specimens (c. 1 000) and population samples (76) have been screened for the occurrence of diploid representatives ofTaraxacum sect.Ruderalia (T. sect.Vulgaria, nom. illeg.). The area studied comprises German Democratic Republic, Poland, Czechoslovakia, Hungary and parts of Austria, Yugoslavia, and Rumania. Diploids are common from the Valley of the Moravia river on southwards. Isolated outpost localities are found in S. Poland and extend far to the north: neighbourhood of Berlin. Based on the pattern of distribution in Czechoslovakia, the Pannonian (thermophilous) phytogeographical character of the diploids is discussed. Special attention has been paid to morphological differences between di- and triploids in Czechoslovakia. The study provides a basis for further biosystematical and taxonomic studies in the relationships between diploids and polyploids as well as in the stability of agamospecies.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 169 (1990), S. 177-207 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Orchidaceae ; Ophrys ; bees ; Melecta ; Eucera ; Anthophora ; Andrena ; Pollination ; pseudocopulation ; Flora of Cyprus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the southern part of Cyprus the pollinator —Ophrys (Orchidaceae) relationships and its specifity have been investigated from the end of February until the middle of March 1986. 12Ophrys spp. were found. To date, only a single pollinator reference has been reported from this island. We found the following pollinators:Melecta tuberculata (Ophrys kotschyi),Eucera dimidiata (Ophrys flavomarginata),Eucera gaullei (Ophrys umbilicata),Eucera paulusi (Ophrys bornmuelleri),Anthophora erschowi (Ophrys elegans),Andrena torda (Ophrys sicula =O. lutea subsp.minor),Andrena cinereophila (Ophrys fusca, small-flowered),Andrena flavipes (Ophrys israelitica),Andrena morio (Ophrys iricolor andOphrys transhyrcana),Andrena bimaculata (Ophrys sphegodes aggr., probably formerly confused withO. transhyrcana). Most interestingly, it could be verified thatO. flavomarginata/O. umbilicata, O. bornmuelleri/O. levantina andO. transhyrcana/O. sphegodes aggr. (possiblyO. sintenisii) are different biospecies. This is a result of genetic isolation due to varying pollinators, and of differences in flower morphology.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 170 (1990), S. 193-204 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Solanaceae ; Physalis ; Hair morphology ; systematics ; hair development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Hair morphology was exammed on developing seedlings and mature plants of ten species from five of seven series inPhysalis. The taxonomic importance of hair development and the distribution of hair types then was evaluated with respect to other comparative data. Two classes of hair types were observed, as found in earlier investigations ofSolanum andRhododendron. The first hair class comprises a sequence from unbranched hairs to dendroid-stelliform hairs. Hairs of this class show considerable variability among taxa in size, presence or absence of glandular tips, and presence and degree of branching, and so were useful in making taxonomic comparisons. The second hair class consists of short hairs, each tipped with a multicellular gland. This second hair class was not useful taxonomically because of its lack of variability in morphology and its often rare occurrence on a plant. The taxa studied exhibit distinctive trichome features which serve to distinguish series and, in some cases together with other data, provided new insight into previously enigmatic species relationships.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 170 (1990), S. 229-236 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteraceae ; Emilia ; Chromosome numbers ; C-banding ; cytogeography ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Analysis of several populations in a large part of the distribution area of the genusEmilia in Brazil has revealed only two species: the diploidE. sonchifolia and the tetraploidE. fosbergii. The more widely reportedE. coccinea was not found. They show a karyotype constancy in morphology and chromosome number (2n = 10 and 2n = 20, respectively), C-banding pattern and number of secondary constrictions. Some indications were found thatE. fosbergii may be an allopolyploid and that its ancestors had different genome sizes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 170 (1990), S. 237-245 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Annonaceae ; Polyalthia littoralis ; Extended spiral thickenings ; flowering phenology ; reproductive biology ; self-pollination ; Malesian tropics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Flowering phenology of some annonaceous trees and reproductive biology ofPolyalthia littoralis (Annonaceae) were studied. The trees showed various types of flowering phenology within the family. Among them,P. littoralis had hermaphroditic and protogynous flowers, and exhibited continuous flowering throughout the year. Bagged flowers set fruits and seeds comparable to the control. The observations of meiotic stages and the results of castrated tests indicated no possibility of apomictic reproduction. The abscised anthers attached to torus by the extended spiral thickenings, and accomplished self-pollination. Outbreeding possibly occurs, but the following self-pollination guarantees seed set.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 171 (1990), S. 57-88 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Inflorescence ; pseudanthium ; pseudocorolla ; flower symmetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pseudanthia occur in more than 40 angiosperm families. With regard to the underlying inflorescence structure they can be classified into the following groups: (a) floral and (b) hyperfloral pseudanthia, each with (c) or without (d) pseudocorollas. Pseudanthia have developed along independent evolutionary lines and are not bound to a particular inflorescence structure. They are the result of (a) the specific morphological predisposition of the taxon concerned, (b) aggregation and diminution of the flowers, giving rise to the formation of an attraction unit (for animal pollination), (c) variation, and (d) selection. Ontogenetical abbreviation is regarded to play an essential role in the origin and elaboration of pseudanthia.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 171 (1990), S. 1-14 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Chemistry ; systematics ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The broad knowledge of the chemistry of theCompositae allows the discussion of its relevance for the systematics and evolution within the family. Furthermore a separation into subfamilies can be supported by the observed differences in the distribution of the main constituents in the tribes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 170 (1990), S. 247-255 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Mimosaceae ; Schrankia nuttallii ; Halictidae ; Bee-pollination ; anthecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Schrankia nuttalii flowers through late spring on the tallgrass prairie. Although each stem produces an average of 26 capitate inflorescences only 12% of those inflorescences will open each day to disperse and receive polyads. Each inflorescence may live up to 48 hours but anthers abscise by late afternoon on the first day and the filaments change color and lose their scent. The 78–93 florets comprising each inflorescence open synchronously before dawn or during early morning hours. First day inflorescences ofS. nuttallii are herkogamous and fragrant. They are nectarless. Bombyliid flies and male bees are infrequent floral foragers so the major pollinators include female bees representing five families;Anthophoridae, Apidae, Colletidae, Halictidae, andMegachilidae. All foraging insects ignore second day inflorescences although stigmas are still receptive. Although 97% of all bees collected onS. nuttallii carrySchrankia polyads in their scopae or corbiculae 59% also carry the pollen/pollinaria of one or more coblooming angiosperms. At least 98% of all bees carrying mixed pollen loads incorporate the pollen/pollinaria of one or more nectariferous taxa (e.g.Asclepias spp.,Asteraceae, Convolvulaceae, Delphinium spec., etc.). Species of halictid bees are more likely to carry pure loads ofS. nuttallii polyads (70%) than bees of the four remaining families. Due to the nectarless florets and high degree of polylectic foraging bee-pollination inS. nuttallii converges more closely with the pollination systems of some AustralianAcacia spp. than with most other xeric/tropical genera of mimosoids studied in the western hemisphere.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 171 (1990), S. 27-55 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Theales ; Medusagynaceae ; Medusagyne ; Systematics ; anatomy ; pollen ; morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The comparative vegetative and reproductive morphology and anatomy of the endangered, monotypic, dicotyledonous genusMedusagyne was studied, and detailed descriptions of leaf, axis, nodal, wood, floral, pollen, fruit, and seed structure are presented. Overall, the genus has many specialized features, including the possession of extreme, habitat-related specializations. Flowers are either bisexual or staminate, and are interpreted as retaining some primitive aspects, such as many free parts spirally arranged on an elongate floral axis. One of the most salient structural features of the plant is the massive development of ensheathing fibrous elements around the vascular system of both vegetative and reproductive tissues. Diffuse foliar sclereids are absent. Particular attention is paid to the unusual multicarpellate, synovarial gynoecium and comparisons are made with theCaryocaraceae. The totality of morphological and anatomical evidence confirms the view thatMedusagyne is a very distinct and evolutionarily isolated genus, best treated as forming the monotypic familyMedusagynaceae. Observations are presented, including the occurrence of stamen fascicle traces, that link the family to the dillenialean and thealean assemblage. Like other isolated thealean taxa,Medusagyne shows affinities to several different families, without having especially close relationships with any particular extant taxon.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteraceae ; Cardueae ; Onopordum nervosum ; Carthamus arborescens ; Cirsium scabrum ; Life cycle ; adaptive strategies ; autoecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The life cycle and autoecology of three Mediterranean thorny species,Onopordum nervosum (Iberian endemic),Cirsium scabrum (Western Mediterranean) andCarthamus arborescens (Iberian-North African), of potential use in agriculture as bioenergetic, forage or oil producing plants were studied. These threeCardueae spp. are good examples of ways in which Mediterranean plants adapt their typical annual cycle to avoid summer droughts.O. nervosum is a perennial, monocarpic, heliophilous species which flowers in early summer and grows even under the extreme xeric conditions of the Mediterranean summers. It is a basiphilous plant usually found in sandy-loamy and sandy-clayey-loamy soils with a marked geographical variability in its seed germination.C. scabrum is a perennial, monocarpic species which has a long life cycle, flowering in summer and growing only during the wet months. It is not well-adapted to droughts and is usually restricted to acid soils.C. arborescens is a perennial, polycarpic species which flowers in spring and dries up in summer. It is usually found in basic loamy-sandy or sandy-loamy soils poor in organic matter.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    ISSN: 1615-6110
    Keywords: Angiosperms ; Iridaceae ; Iris pumila ; Phenotypic plasticity ; morphological variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Variation patterns in phenotypic plasticity and broad sense heritability of 26 characters were examined within and among closely adjacent habitats of the bearded iris,Iris pumila. It was found thatI. pumila has considerable differentiation for phenotypic plasticity and genetic variation over short distances. An analysis of relationships between character differentiation and phenotypic plasticity suggests that they could have evolved independently. Possible mechanisms for maintaining local differentiation of the observed plastic and genetic variation are also discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 170 (1990), S. 53-70 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Potamogetonaceae ; Potamogeton malaianus ; P. sumatranus ; P. wrightii ; Description ; distribution ; taxonomic evaluation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The type specimens ofP. malaianus Miquel collected byTeijsman are not identical withP. wrightii Morong, a species calledP. “malaianus” in Japan and elsewhere; they belong toP. nodosus. As a possible candidate for the correct name,P. sumatranus Miquel was studied: its exact identity, however, cannot be proved beyond doubt, even though the name refers at least partly toP. wrightii. That is whyPotamogeton wrightii Morong is proposed as the valid name of the species. A thorough description is provided including data on anatomy, morphology, life history, variability and ecology. A complete list of specimens, of synonyms and of misidentifications is given as well. The species shows a fuzzy structure with several special forms, intergrading hybrids; it is closely related with other taxa likeP. sumatranus. Still a great number of specimens cannot be assigned with certainty to any taxon.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 170 (1990), S. 97-106 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Gentianaceae ; Lisianthius ; Population variation ; ribosomal DNA ; isozymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Restriction endonuclease fragment analysis of nuclear ribosomal DNA (rDNA) was completed on 25 individuals each from seven populations of theLisianthius skinneri (Gentianaceae) species complex in Panama. Seven restriction enzymes were used to determine the amount and type of rDNA variation within and among individuals of the populations. No restriction site variation was seen within populations or individuals although site differences were seen among populations. Spacer length variation within and among individuals of populations was mapped to the internal transcribed spacer (ITS) region between the 18S and 5.8S rRNA genes, a region inLisianthius rDNA that previously was shown to exhibit length differences among populations. This is the first reported case of such variation within and among individuals of populations for the ITS region. Presence or absence of ITS spacer length variation is not correlated with levels of isozymic heterozygosity within populations. No detectable length variation within individuals or populations was seen in the larger intergenic spacer (IGS). Although populations varied with respect to IGS length, all individuals of a given population had a single and equivalent IGS length.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 172 (1990), S. 65-75 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Rosaceae ; Rubus ; Chloroplast DNA ; restriction fragment length polymorphism ; cladistic analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The variability in chloroplast DNA type of 20Rubus genotypes was examined by Southern hybridization. DNA extracted from theRubus accessions was digested with two restriction enzymes (EcoRI and EcoRV) and heterologous chloroplast DNA sequences from barley and pea were used as probes to detectRubus chloroplast DNA sequences on Southern blots ofRubus total DNA. Restriction fragment length polymorphism was detected and a total of 92 restriction fragments were generated by the probe/enzyme combinations examined. Cladistic principles based on the parsimony assumption were used to assemble a phylogenetic tree based on chloroplast restriction fragment length data. The phylogenetic tree grouped the taxonomically defined species and is in general agreement with information based on morphological criteria. However, the Japanese red raspberryR. illecebrosus was shown to have diverged considerably in terms of evolutionary time from other species in subg.Idaeobatus. Furthermore, the molecular approach provides a quantitative estimate of the relationship between species that is difficult to obtain from morphological data. In order to complement the chloroplast DNA information a ribosomal DNA probe was also included in the analysis and provided further information on the phylogenetic relationships withinRubus.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 211 (1998), S. 43-56 
    ISSN: 1615-6110
    Keywords: Ranunculaceae ; Adonis ; Morphology ; growth pattern ; taxonomy ; ecology ; climatic requirements ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Adonis sect.Consiligo is split into three subsections based on morphology, growth pattern, pollen and fruit morphology. For all species distribution maps are provided and discussed with regard to their ecology and climatic requirements. These data reveal additional characters that support the classification of the taxa. Most species of the section grow in continental Eurasiatic steppes and mountain steppe habitats. Only the species of subsect.Amurenses grow in Far Eastern temperate forests and prefer a more oceanic climate. The taxonomic position of these strongly divergent species is supported by the distributional and ecological data. The evolution ofAdonis sect.Consiligo occurred under strong climatic control. During evolution the taxa could only slightly widen their ecological amplitude and, thus, ecology remained rather stable except that of the subsect.Amurenses. Ecological and distributional data can be used to validate taxonomy and phylogeny and reveal additional informations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    ISSN: 1615-6110
    Keywords: Alstroemeriaceae ; Alstroemeria aurea ; A. ligtu ; A. magnifica ; C-band polymorphism ; evolution ; flow cytometry ; genome size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Among a total of 43 accessions ofAlstroemeria aurea, A. ligtu andA. magnifica nuclear DNA amounts (2C-values) showed significant intraspecific variation, 1.09, 1.21 and 1.15 fold, respectively, when determined through flow cytometric measurements of fluorescence of propidium iodide (PI) stained nuclei. After staining with another fluorochrome, 4′,6-diamidino-2-phenylindole (DAPI), an intraspecific variation of 1.10, 1.11 and 1.12 fold, respectively, was found. C-band polymorphisms were present among and within the accessions of all three species. In some cases only very small differences in C-banding pattern were observed. In other cases, however, differences were more prominent. Besides C-band polymorphism, there were also instances of chromosome length polymorphism, which concerned the total chromosome complement or single chromosomes. The variation in nuclear DNA amount inA. aurea andA. ligtu was more or less continuous, except for one accession ofA. ligtu subsp.simsii. Artificial selection and possibly introgression of chromosomes from other species may have moulded the karyotypes of some of the accessions ofA. aurea, a species that has been under cultivation for more than 160 years. The variation as observed inA. magnifica subsp.magnifica was discontinuous and could be due to a broad species concept.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Triticum araraticum ; Karyotype ; C-banding ; intraspecific divergence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract DifferentTriticum araraticum lines were studied by C-banding method. The intraspecific divergence ofT. araraticum was shown to be caused mainly by large chromosomal rearrangements. Two main chromosomal types were distinguished among the studied lines: (1) a karyotype similar to that ofT. timopheevii and (2) different one. The first type includes some lines ofT. araraticum subspp.kurdistanicum andararaticum; the second comprises most lines ofT. araraticum subsp.araraticum. The lines of the first type can give fertile F1 hybrids withT. timopheevii.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 169 (1990), S. 55-63 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Gesneriaceae ; Monophyllaea ; M. hirtella ; M. horsfieldii ; Chromosome number ; hybridization ; fertility ; tropical rain forest ; habitat segregation ; Flora of Indonesia ; Sumatra
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A natural hybrid (2n = 21) between the parapatric rain forest speciesMonophyllaea hirtella (2n = 20) andM. horsfieldii (2n = 22) (Gesneriaceae) has been observed at Sg. Lubuk Paraku, Padang, W. Sumatra. The hybrids showed intermediary characters between the parental species in the inflorescence structure, flower size and colour, indumentum, chromosome numbers, and habitat. The 29% pollen fertility of a single hybrid specimen suggests that the genetical isolation between the parental species may break down and reproduction over subsequent generations may occur.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 169 (1990), S. 69-80 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Onagraceae ; Oenothera sect.Oenothera subsect.Oenothera ; O. nutans ; Chromosomal analysis ; complex analysis ; structural heterozygosity ; complex heterozygosity ; taxonomy ; numerical taxonomy ; factor analysis ; reciprocal translocations ; Sifactors ; lethal factors ; sublethal factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Oenothera nutans, common to the Appalachian Mts between 650 and 1 700 m altitude, was investigated cytogenetically and taxonomically. The species is permanently structurally heterozygous. It consists of two genomes of the B-type which are more or less indistinguishable phenotypically. Nearly all of the strains investigated possess a self-incompatibility factor in one of the two complexes. Both complexes show a close relationship to the predominantly homozygousO. grandiflora, a native of the southern lowlands.O. nutans andO. grandiflora possess the same plastid type, plastome III. Probably,O. nutans evolved by an accumulation of reciprocal translocations within an originally structurally homozygous population, which must be regarded ancestral to the present forms ofO. grandiflora.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 169 (1990), S. 111-121 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Aesculus californica ; Amsinckia lunaris ; Brodiaea pulchella ; Carduus pycnocephalus ; butterflies ; Battus philenor ; Heliconius ; Pollen amino acids ; diffusion ; nectar ; butterfly-feeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The increase of the amino acid concentration over different time intervals in artificial nectar (i.e., a sucrose solution) due to pollen contamination was investigated in four Californian plant species (Aesculus californica, Amsinckia lunaris, Brodiaea pulchella, Carduus pycnocephalus), which are important nectar resources for a Californian colony of the butterflyBattus philenor as well as for other insects. The increase of the amino acid concentration in the medium is different in all four species and seems to be determined by a variety of factors including permeability of the pollen grain wall and presence or absence of pores. The results suggest a passive diffusion process of the free pollen amino acids into the medium rather than an active release. Implications from the experiments forBattus philenor and for other nectar feeding pollinators are discussed. A possible complementary effect of free pollen and nectar amino acids is proposed for plant species in which pollen is likely to be knocked into nectar by their flower visitors. A possible evolutionary pathway from nectar feeding butterflies such asBattus philenor to the complex derived pollen feeding habit in theHeliconius butterflies is proposed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    ISSN: 1615-6110
    Keywords: Angiosperms ; Orchidaceae ; Thelymitra epipactoides ; bees ; Nomia ; Lasioglossum ; Pollination ; deceit ; floral mimicry ; Flora of Australia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Thelymitra epipactoides has a highly variable visual display achieved through polychromatic flowers and variable inflorescence size, bearing between 7 and 31 flowers, which attract foraging polylectic bees. Only bees of the genusNomia were observed carrying pollinia and successfully pollinating the orchid. The genusNomia contains polylectic, pollen gathering species that store pollen in both the crop and scopa on the hind legs. The absence of a reward for the bees indicates the orchid is relying on deception to attract visitors. The relationship of deception to mimicry is discussed. Once on the flower, tactile, visual and possibly olfactory stimuli direct bees to the false anther formed by the voluminous column wings, where morphological adaptations of the flower ensure that the pollinarium is deposited on the gaster of the bee to effect pollination. — The lack of seed set observed on the Victorian coast appears to be due to the absence of pollinators from the heath and grassland communities in which the orchid grows. This may well be a consequence of the reduced number of plants flowering in the community (a result of the elimination of fire at these sites), thus not maintaining a floral community attractive to potential pollinators.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 170 (1990), S. 125-132 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Caryophyllaceae ; Dianthus gratianopolitanus ; Pollination ; psychophily ; phalaenophily ; nectar composition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pollination ofDianthus gratianopolitanus was studied in a population of the Swiss Jura mountains. Pollinators of this plant species are reported here for the first time. The flowers were not only visited by butterflies as postulated in the literature, but also by diurnal hawkmoths (Macroglossum stellatarum) and by diurnal and nocturnal noctuid moths. — Nectar is sucrose-dominant, the sugar concentration is moderate but the amino acid concentration is high. Nectar characteristics correspond well with the syndrome ofLepidoptera-pollinated flowers. — Field observations and flower characters (colour, range of the calyx length) suggest thatDianthus gratianopolitanus is an intermediate species in the transition of butterfly to moth pollination. — Lack of reproductive success inDianthus gratianopolitanus can not be attributed to lack of suitable pollinators.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    ISSN: 1615-6110
    Keywords: Angiosperms ; Rubiaceae ; Ixora ; I. platythyrsa ; Moth-pollination ; secondary pollen presentation ; Flora of Madagascar
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The pollination biology ofIxora platythyrsa (Rubiaceae) was studied in NW. Madagascar. The plant displayed cream-yellow, nocturnally fragrant, nectariferous, tubular and strongly protandrous flowers. These had an “ixoroid” secondary pollen presentation mechanism: prior to anthesis, anthers exhausted their pollen onto unripe stylar heads. From this position pollen of male-stage flowers later adhered to primarily the probosces of small visiting nocturnal noctuid and geometrid moths. — Pollen was subsequently raked off moths' probosces by receptive, copiously papillose stigmas of female-stage flowers. Principal pollination adaptation was probably to the noctuid moth subfam.Sarrothripinae.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 171 (1990), S. 129-134 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Balanophoraceae ; Balanophora ; Tuber surface morphology ; systematics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The surface ofBalanophora tubers consists of a nonepidermal layer made up of two distinctive types of cells, armature cells and stellate wart cells. Both cell types are provided with a heavy wall, and are dead at maturity. Stellate warts in the three species investigated,B. elongata, B. fungosa, andB. hansenii, séem to be uniform in appearance, but armature cells are extremely distinctive for each species. They are present in large, agglomerate masses in the first, singly or in very small clusters in the second, and as completely free, individual, acicular cells in the third species. Such differences are believed to be significant systematically, and the separation ofB. hansenii is thus probably justified. Notwithstanding superficial similarities, stellate warts do not seem to be comparable to the lenticels of other plants.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 171 (1990), S. 205-220 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Secale ; Ribosomal DNA ; spacer subrepeats ; restriction fragment length polymorphism (RFLP) ; phenetic relationships
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Variation in ribosomal DNA spacer length was analysed in 23 populations of 12Secale spp. by restriction enzyme analysis. Digestion of rDNA with Taq I endonuclease enzyme yields spacer fragments that include the subrepeat array and the non-repetitive region downstream of the array. Extensive spacer length variation existed in most species with Taq I fragment lengths ranging from 0.9–3.1 kb. These length variants have been attributed to the differences in number of 134 bp spacer subrepeats within rDNA arrays.S. silvestre was the only species to exhibit a unique spacer length variant of 0.9 kb and this was shown to result from the presence of an extra Taq I site in the spacer. rDNA spacer length frequencies were determined for the species. These frequencies were used to derive phenetic relationships between the species by numerical taxonomic methods. In plots constructed fromGower's distance matrices,S. silvestre appeared well separated from the major cluster consisting of the other species. On the basis of morphological and cytogenetic criteria,S. silvestre is considered the most ancient species. The rDNA data is consistent with this interpretation as it shows a clear differentiation ofS. silvestre from all the other species based on length and nucleotide sequence composition of the spacer region.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Sorghum vulgare ; great millet ; DNA hybridization ; repetitive DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The 1.4 kbp Xba I and the 1.3 kbp EcoRI repeat families in great millet were partially characterized with respect to their genomic distribution and their homology with the EcoRI and Xba I families of five other millet DNAs. The digestions of great millet DNA using increasing amounts of the two enzymes show that these two families are disperse in nature. The hybridization of these two families to the genomic digests of great millet indicates that they are arranged in a clustered and scrambled manner. Similarly, the hybridization with the EcoRI and Xba I digests of five other millet DNAs reveals the speciesspecific nature of these two repeat families. The latter also hybridize to the total repetitive fraction of great millet isolated at a highly stringent temperature of 75°C suggesting that the members of these two families are probably largely homogeneous.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 171 (1990), S. 147-155 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Oxalidaceae ; Oxalis violacea ; Andrenidae ; Bombyliidae ; Halictidae ; Megachilidae ; Pollination ecology ; heterostyly
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Vernal grass fires may encourage profuse flowering in clonal, colonies ofOxalis violacea. Long-styled colonies appear to be more floriferous than short-styled colonies and set a greater number of capsules. Individual flowers of both morphs live one or two days, change position on their respective pedicels and advertise nectar concealed at the base of the floral throat. AlthoughDiptera, Hymenoptera, andLepidoptera forage for nectar, bees (Andrenidae,Anthophoridae, Halictidae, andMegachilidae) probably make the only effective pollen transfers between the two morphs. Both male and female bees may transport pollen of both morphs and short-tongued bees (e.g.,Augochlorella spp.,Dialictus spp.) may be more common but as effective as pollinators as long-tongued bees (e.g.,Calliopsis andreniformis andHoplitis spp.). The conversion rate of flowers into capsules is only 13–17%. The spreading style in the short-styled morph is interpreted as an adaptation restricting insect-mediated, self-pollination but encouraging bee-stigma contact during nectar foraging.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 171 (1990), S. 187-197 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Aceraceae ; Acer ; Sympodial and monopodial branching ; evolution ; adaptive strategy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The evolutionary trend and its ecological implications in sympodial and monopodial branching patterns has been investigated in 20 JapaneseAcer spp. through comparison of shoot tip abortion and terminal bud formation. The genus is divided into two species groups according to its branching pattern, one (6 species) predominantly exhibiting sympodial branching with frequent monopodial branching in short shoots (sympodial species), and the other (14 species) exhibiting only monopodial branching (monopodial species). The early ontogeny of leaf and bud scales is described. Despite the difference in branching patterns, the bud scales of terminal buds are essentially the same in having a leaf base developed to function as a protecting organ. In all the sympodial species, during the abortion of a sympodium shoot tip, one or two pairs of primordia were found to occur on the apex, and later wither. These primordia resemble bud scales of terminal buds in their ontogeny and morphology, and appear to be rudimentary. It is suggested that a rudimentary terminal bud develops together with the establishment of sympodial branching, and that sympodial branching has originated from monopodial branching. Based on this proposed evolutionary trend, it is suggested thatAcer has moved from less shady habitats into shady habitats with monopodial branching (advantageous for vertical growth) changing into sympodial branching (advantageous for lateral spread).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 171 (1990), S. 233-248 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Lactuca sativa ; L. serriola ; L. saligna ; L. virosa ; Hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The degree of relationships withinLactuca sativa and three wild relativesL. serriola, L. saligna, andL. virosa was studied by observing the performance, vigour and fertility of the F 1 hybrids obtained from crosses made in and between the four species. The crosses ofL. saligna ×L. virosa and the reciprocal crosses produced no hybrids.L. saligna andL. virosa are the least related of the four species.L. sativa ×L. serriola and the reciprocal crosses were successful and produced fertile hybrids These two species are genetically very closely related.L. saligna is known to produce, as a female parent, hybrids withL. sativa andL. serriola. Now the reciprocal cross was successful for the first time, so the unability to obtain hybrids in the past was based on the choice of accessions and not caused by unilateral incompatibility.L. virosa ×L. sativa and the reciprocal combination produced hybrids. The combinationL. serriola ×L. virosa produced hybrids with very limited fertility. In contrast to earlier reports (sterile hybrids) one combination of the reciprocal cross too produced hybrids with very limited fertility.—Some of theL. saligna ×L. sativa (and reciprocal) hybrids were found to look strikingly likeL. serriola. This adds evidence for the descent ofL. serriola andL. sativa:L. saligna also made part of the ancestral complex of the cultivated lettuce.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 170 (1990), S. 107-124 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Betulaceae ; Alnus ; Isozymes ; population genetics ; hybridization ; genetic distance ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The actinorhizal genusAlnus contains numerous taxa that have been morphologically classified into different subgenera, species and subspecies. The genetic divergence has been evaluated within subg.Alnobetula between the parapatric taxaAlnus sinuata andA. crispa, using diversity of allozyme markers at 15 structural loci among 20 populations. Evidence for introgressive hybridization at the overlap of their ranges was noted in three populations. However, the width of the hybrid zone appeared tenuous. The average genetic distance derived from the comparisons of conspecific populations was much smaller than the interspecific distance (D = 0.047). This allelic divergence was also paralleled with larger amounts of allelic and genotypic diversity within and among populations ofA. sinuata, which are occupying a more heterogenous ecological niche. It is proposed that the repeated advances and retreats of the ice sheet during the Pleistocene may have promoted the divergence and allopatric evolution of these subspecies, and that secondary contact may have occurred repeatedly during the interglacial periods. The dynamic-equilibrium model would predict in such cases that narrow hybrid zones, formed at the contact of parapatric ranges, would impede gene exchange between parental taxa by selection against hybrids. The results obtained in this study seemed concordant with this hypothesis, as they were also in agreement with the existent taxonomical treatment of these taxa based on morphology.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 170 (1990), S. 151-159 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Geraniaceae ; Pelargonium ; Chromosome numbers ; karyotypes ; karyotype evolution ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pelargonium sect.Ciconium and sect.Dibrachya have a basic chromosome number of x = 9, whereas sect.Jenkinsonia has x = 9, 11, and 17.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 170 (1990), S. 257-263 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Scrophulariaceae ; Striga ; Buchnera ; Seed coat morphology ; systematics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Seeds of the root parasitesStriga (several spp.) andBuchnera americana were examined by means of SEM. The surface patterns of the seeds in both genera resemble each other closely, especially those ofS. angustifolia andB. americana. SomeStriga spp. can be clearly distinguished by their surface characteristics, while this is quite difficult in others. The taxonomic value of the seed surface features ofStriga andBuchnera is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 171 (1990), S. 15-26 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Geraniaceae ; Pelargonium sect.Glaucophyllum ; Morphology ; pollen ; chromosome numbers ; flavonoids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pelargonium otaviense Knuth andP. spinosum Willd. are excluded from sect.Glaucophyllum, whileP. grandiflorum (Andr.)Willd.,P. patulum Jacq. andP. tabulare (Burm. f.)L'Hérit. of sect.Eumorpha are included. Sect.Glaucophyllum is characterized by green to glaucous vegetative organs and zygomorphic white to pink corolla with five narrow petals. All the species have an identical pollen and chromosome morphology, the same basic chromosome number (x = 11) and similar flavonoid patterns. A close relationship between sect.Glaucophyllum and sect.Pelargonium is indicated by the occurrence of natural hybrids and concordant characters. Isorhamnetin and luteolin have been detected in the genus for the first time.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 171 (1990), S. 99-115 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Malvaceae ; Gossypium ; Chloroplast DNA ; allozymes ; isozymes ; molecular evolution ; long-distance dispersal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Molecular divergence betweenGossypium klotzschianum andG. davidsonii was studied. The former is endemic to five of the larger islands of the Galapagos, whileG. davidsonii is restricted to the southern half of Baja California, approximately 2 500 km distant. A substantial body of genetic and taxonomic data suggests that these two species are related as progenitor and derivative. Interspecific hybrids are fully fertile, with no evidence of F2 breakdown and normal segregation of genetic markers. Allozyme analysis of 33 populations for 41 loci indicated that the allelic composition ofG. klotzschianum represents a subset ofG. davidsonii. Although genetic diversity is relatively restricted in both species, calculated measures demonstrate higher levels of genetic variability and greater population structuring inG. davidsonii than inG. klotzschianum. The interspecific genetic identity of 0.87 is typical for progenitor-derivative species pairs. Chloroplast DNAs were surveyed for variation with 25 restriction enzymes using hybridization probes that cover the entire chloroplast genome. No intraspecific and little interspecific variation was detected among 560 cpDNA restriction sites, representing sequence information for approximately 3200 nucleotides. Only 3 mutational differences distinguished the two species, resulting in a sequence divergence estimate of 0.09%. Divergence times were estimated from both the isozyme data and the cpDNA restriction site data. Although these estimates have several sources of error, both molecular data sets were congruent in suggesting that the two lineages diverged between 250000 and 700000 years ago. Accumulated evidence suggests that dispersal was from Baja California to the Galapagos Islands rather than the reverse, and most likely was mediated by trans-oceanic drift.G. klotzschianum may be the only species of the endemic Galapagos flora to have arisen from a northern Mexican progenitor.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 171 (1990), S. 157-185 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Apocynaceae ; Plumerioideae ; Apocynoideae ; Holarrheninae ; Holarrhena ; Carruthersia ; Spirolobium ; Floral structure ; pollen morphology ; indole alkaloids ; steroidal alkaloids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The genusHolarrhena, described byRobert Brown in 1811, has had a problematic taxonomic history, in part due to a suite of characters that does not conform with accepted concepts within theApocynaceae. In a number of important taxonomic charactersHolarrhena is typical of subfam.Apocynoideae. But due to the relatively unspecialized structure of the anthers most recent authors have placedHolarrheng, together withCarruthersia andSpirolobium, as the subtribeHolarrheninae in subfam.Plumerioideae. For the present investigation the floral structure and pollen morphology ofHolarrhena, Carruthersia andSpirolobium were analyzed. From the chemical literature reports of the occurrence of steroidal alkaloids in thePlumerioideae were evaluated. Our results indicate that the three genera belong to subfam.Apocynoideae in the tribeNerieae, but that the “Holarrheninae” is an unnatural group, and that the three genera should be accommodated individually within the tribe.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    ISSN: 1615-6110
    Keywords: Angiosperms ; Oleaceae ; Olea europaea ; Endoplasmic reticulum ; stacks cisternae ; pollen grain ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Characteristic features of rough endoplasmic reticulum (rER) distribution and proliferation were noted during olive pollen (Olea europaea L.) development, suggesting the physiological significance of this organelle. Initially scarce in the young microspore, ER increases as cytoplasmic vacuoles form. At the vacuolated microspore stage the cytoplasm contains numberous polysomes and elongated rER cisternae arranged preferentially in stacks, with an average intracisternal width of 0.07 µm. Stacks persist in the bicellular pollen grain but consist of fewer, shorter, dilated cisternae (mean intracisternal width 0.1 µm) containing a considerable electron-dense matrix. Cisternae in the mature grain are fragmented, leaving behind an ER of swollen pockets. Pockets of ER containing a material of greater electron density are evenly deposited along the plasmalemma, in close relation with it. A dense material is seen in the tubules of the apertural region, which was lacking in earlier stages. Our results show that ER may be involved in protein transport to the intine.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 172 (1990), S. 35-49 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Guttiferae ; Kielmeyera coriacea ; K. speciosa ; “Buzz pollination” ; carpenter bees ; breeding system ; andromonoecy ; self-mimicry ; neotropical savanna
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The pollination biology and breeding systems ofKielmeyera coriacea andK. speciosa, two sympatric woody species common in the cerrado vegetation of C. Brazil, were studied. Both species have similar nectarless, polystemonous “Papaver-type” flowers which are visited by a similar spectrum of insects, though they bloom in different seasons and are thus phenologically isolated. Large carpenter bees seem to be the most important pollinators and these and other bees effect “buzz pollen” retrieval despite the fact that anthers are not poricidal. Both species ofKielmeyera possess strong xenogamous breeding systems. The presence of staminate flowers and andromonoecy inK. coriacea, as well as the longevity ofK. speciosa flowers are discussed as alternative strategies to improve pollination success and reproductive efficacy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    ISSN: 1615-6110
    Keywords: Angiosperms ; Apocynaceae ; Tabernaemontana ; Indole alkaloids ; chemotaxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract According to their alkaloidal products species of the “new” genusTabernaemontana can be partly differentiated. This differentiation is in agreement with the “old” genera classification. From the chemotaxonomic point of view a subdivision of subfam.Plumerioideae of theApocynaceae is proposed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 172 (1990), S. 51-63 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Fumariaceae ; Papaveraceae ; Fumaria ; Phenetics ; numerical taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The taxonomy of the genusFumaria has not been considered in detail sincePugsley's work in 1919 ff., and few modern methods have been applied to it. In a phenetic study, 33 populations of 11Fumaria spp. were grown in uniform conditions, and seven morphological characters measured. After re-expression and transformation the data were analysed by cluster analysis and principal components analysis. Alternative analyses did not indicate contradictory taxonomic conclusions. Artificial crosses gave some evidence on interfertility, and suggestedF. occidentalis to be an allopolyploid ofF. bastardii ×F. capreolata. Pugsley's subsectional classification is supported within sect.Parviflora, but not within sect.Grandiflora. His two sections are seen to be meaningful, but not discrete.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 172 (1990), S. 83-97 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Pooideae ; Phylogenetics ; evolution ; chloroplast DNA ; restriction site variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A phylogenetic analysis was conducted on chloroplast DNA restriction site variation in 34 genera of grasses (familyPoaceae), including 28 genera from subfam.Pooideae (representing tribesAveneae, Brachypodieae, Bromeae, Meliceae, Poeae, Stipeae, andTriticeae) and representatives of three other subfamilies,Arundinoideae, Oryzoideae, andPanicoideae. Analyses of all 34 genera always distinguishedPooideae as monophyletic, regardless of which nonpooid genus functioned as outgroup; six separate analyses of all 28 pooid genera, each including one of the six nonpooid genera as outgroup, resolved five identically-constituted clades withinPooideae (in four cases), or (in the other two cases) yielded results that were less well resolved, but not in conflict with those of the other four analyses. The four best-resolved analyses distinguishedMeliceae as the earliest diverging lineage withinPooideae, andStipeae as the next. Above the point of divergence ofStipeae is a dichotomy between supertribeTriticodae (including tribesBrachypodieae, Bromeae, andTriticeae), and a clade comprisingPoeae andAveneae. The analysis supports some tribal realignments, specifically the assignment ofBriza, Chascolytrum, Microbriza, andTorreyochloa toAveneae, andArctagrostis, Catabrosa, andSesleria toPoeae. The analysis also suggests that the pooid spikelet (i.e., glumes shorter than lemmas and florets two or more) is plesiomorphic inPooideae, and that spikelets with one floret, and those with glumes longer than the first lemma, each have evolved more than once withinPooideae. Results also indicate that small chromosomes and chromosome numbers based on x=c. 10−12 are plesiomorphic withinPooideae. Alternative states of these characters (chromosomes large, chromosome numbers based on x=7) are interpreted as synapomorphies or parallelisms of clades that includeTriticodae, Aveneae, andPoeae. Lanceolate lodicule shape may be a synapomorphy of the clade that includesStipeae, Triticodae, Aveneae, andPoeae, and loss of lodicule vascularization a synapomorphy of the entirePooideae.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 172 (1990), S. 99-118 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Myrtaceae ; Eucalyptus ; Rarity ; allozymes ; phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phylogenetic relationships among the 12 species of the “green ash” group of eucalypts were examined using allozyme data, to investigate the causes of rarity in three localized endemics of the group. The relationships suggested by the allozyme data showed both similarities to and differences from those estimated from morphological data byLadiges and coworkers. The phylogenetic relationships suggest that rarity inEucalyptus burgessiana may be related to recent divergence, whileE. paliformis andE. rupicola are relatively old species, more likely to be relicts, and/or restricted to a rare habitat.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 172 (1990), S. 77-82 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Iridaceae ; Crocus vernus subsp.vernus ; Embryology ; mentor effect ; pollen tube ; self-incompatibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Outcross, self- and mixed pollinations were performed inCrocus vernus subsp.vernus, a species with bicellular pollen, dry stigmas and hollow style. No differences were noted among the above pollinations concerning the germination of pollen and the growth of pollen tubes until the top of ovary. Within 45 min after pollinations 62% of pollen grains germinated. Pollen tubes penetrated the papilla cuticle extending along the papilla wall; on entry into stigmatic lobes they continued growth in the stylar secretion to ovarian locules. Here, however, self-pollen tubes failed to reach or to enter the ovule micropyle; while pollen tubes from either outcross- or mixed pollinations grew until fertilizing ovules. These observations gave evidence of a self-incompatibility system inCrocus, which appeared to be neutralized by mentor effect. The ovary as site of incompatibility response is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 172 (1990), S. 141-150 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Hordeum bulbosum ; Cytotypes ; chromosome analysis ; Giemsa C-banding patterns ; autopolyploidy ; relationships
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The similar-looking basic genomes ofHordeum bulbosum (2x and 4x) have five rather similar metacentric, one submetacentric, and one satellited choromosome. C-banding patterns are characterized by one or two centromeric, or juxtacentromeric, small to larger bands in most chromosomes, by bands at the nucleolar organizers, by small or very small telomeric bands, and by the nearly complete lack of intercalary bands. Banding pattern polymorphism is widespread. Banding patterns supported by chromosome morphology enable identification of homologues, and discrimination between non-homologues inH. bulbosum (2x). The C-banded karyotype ofH. bulbosum (4x) supports an autopolyploid origin, but it was possible to identify only homologues of submetacentrics and SAT-chromosomes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 172 (1990), S. 193-203 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Actinidiaceae ; Actinidia ; Chloroplast genome ; kiwifruit ; molecular evolution ; phylogenetic trees ; restriction fragment length polymorphism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A series of chloroplast and nuclear probes were used to examine restriction fragment length polymorphisms (RFLPs) in kiwifruit (Actinidia deliciosa) and three of its closest relatives. The four species fell into two pairs, withA. chinensis andA. deliciosa closely related but some distance away from the other two species,A. latifolia andA. eriantha. The results are consistent with the hypothesis that the diploid species,A. chinensis, is a precursor ofA. deliciosa, which is hexaploid.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 172 (1990), S. 127-139 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Fagaceae ; Quercus ; Gene mapping ; ribosomal RNA genes ; rRNA/DNA hybridization ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The taxonomy of the genusQuercus is still unclear. In order to elucidate the taxonomy of Mediterranean oaks we have analyzed ribosomal RNA genes ofQuercus cerris, Q. coccifera, Q. trojana, Q. ilex, Q. suber, andQ. macrolepis by means of Southern blot hybridization. Oak nuclear DNA was extracted from root tips of 300 acorns and from catkins of single plants. EcoRI and BamHI restriction endonucleases were used. DNA electrophoresis and rRNA/DNA hybridization were performed usingVicia faba rRNA 18 S and 25 S as probes. The rRNA genes of all the species studied have an identical restriction mapping in the 18 S and 25 S regions, while differences in length are present in the intergenic regions.Q. cerris possesses at least four types of genes of 12.1, 11.5, 8.5, and 8.3 kb;Q. coccifera at least three types of 12.4, 10.4, and 10.1 kb;Q. trojana possesses the same rRNA genes asQ. cerris plus another gene type 12.0 kb long, with EcoRI and BamHI restriction sites in the intergenic spacer;Q. ilex at least three types of 12.4, 10.85, and 9.5 kb;Q. suber at least five types of 11.5, 11.0, 8.6, 8.5, and 8.3 kb;Q. macrolepis, finally, at least seven types of 11.5, 11.0, 10.2, 8.6, 8.5, 8.3, and 8.15 kb.Q. coccifera andQ. ilex rDNA appears quite different respect to other species examined, while high similarity seems to exist betweenQ. cerris, Q. trojana, Q. suber, andQ. macrolepis. These results are in agreement with the taxonomic model proposed bySchwarz for the genusQuercus.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 172 (1990), S. 205-213 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Brassicaceae ; Capsella ; Ribulose-1,5-bisphosphate carboxylase/oxygenase ; isoelectric focusing ; evolution ; polyploidization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco, EC 4.1.1.39) and its subunits (large subunits = LSU, small subunits = SSU) were isolated from threeCapsella spp. by gel electrophoresis and polypeptide composition was analyzed by isoelectric focusing (IEF) in the presence of 8M urea. The described techniques are recommended for large scale systematic studies. Multiple IEF banding patterns of the SSU are probably the outcome of a heterogenous multigene family. The two diploid speciesC. rubella andC. grandiflora show an identical IEF pattern and could be differentiated from the putative allotetraploidC. bursa-pastoris only by the SSU banding pattern. Uniqueness of some SSU bands in the tetraploid and in the two diploid species, respectively, may indicate an ancient alloploid origin of tetraploidC. bursa-pastoris followed by events leading to divergences in the genomes of the allotetraploid and its presumed diploid progenitors after the hybridization event (SSU gene elimination, acquisition of new SSU genes).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 172 (1990), S. 215-227 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Amaryllidaceae ; Narcissus ; Linaceae ; Hugonia ; Bauhinia ; Cleome ; Aneilema ; Agelaea ; Heterostyly ; tristyly ; distyly
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The hypothesis ofHenriques andFernandes that several Iberian species ofNarcissus (Amaryllidaceae) are tristylous is reconsidered. Contrary to the opinion ofBateman and most subsequent authors, we believe that the available evidence indicates that some populations ofN. triandrus andN. fernandesii, at least, are tristylous; other populations ofN. triandrus are distylous.Hugonia cf.penicillanthemum (Linaceae) from new Caledonia is distylous, but it remains possible that other species ofHugonia are tristylous. The disputed occurrence of heterostyly in S. African species ofBauhinia (Leguminosae),Cleome (Capparaceae) andAneilema (Commelinaceae), and inAgelaea (Connaraceae) is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 172 (1990), S. 151-192 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Polygonaceae ; Rumex subg.Rumex sect.Axillares ; Taxonomy ; systematics ; hybridization ; Flora of S. America
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resumen Rumex secciónAxillares fue descrito por primera vez por el autor en 1937. Se conoce en América del Norte con 20 especies endémicas. De América del Sur se conocían sólo 5 especies, todas ellas endemicas; este número asciende a 15 en la presente revision. Fuera de las Américas se encuentran pequeños grupos de especies endémicas en Sudáfrica, en las Islas de Hawaii y en Australia; especies aisladas se encuentran en Africa Central, en las lejanas Islas Atlánticas de Tristan de Cunha y Gough Island y en Asia Oriental. La sección no tiene representantes en Europa, con excepción de tres especies americanas introducidas, poco frecuentes. La secciónAxillares se caracteriza bien, tanto morfológicamente por su forma de creciemiento—sin rosetas foliares, período floral prácticamente ilimitado por la formación de inflorescencias axilares parciales, flores a menudo monoicas—como por su estructura genética que se manifiesta en un comportamiento diferente de hibridación. Híbridos son frecuentes en las especies de la secciónRumex (syn.Simplices) y reconocibles por su esterilidad que se expresa en cierta particularidad del habito. Al contrario, no hay seguridad de híbridos espontáneos en la secciónAxillares. La mayor parte de los híbridos artificiales son totalmente fértiles. Hasta ahora se conocían solo tres híbridos entre las especies de ambas secciones. Otros tres han sido encontrados por el autor en Chile. Todos completamente estériles y con las características de hábito típicas resultantes la esterilidad, como ocurre en los híbridos de la secciónRumex.
    Notes: Abstract Rumex sect.Axillares first described by the author in 1937 is known to be represented in N. America by 20 endemic species. From S. America only five species, all endemic, were previously known; this number is raised in the present revision to 15. Outside America there exist small groups of endemic species in S. Africa and in the islands of Hawaii as well as in Australia and scattered single species in C. Africa, on the remote Atlantic islands of Tristan de Cunha and Gough Island, and in eastern Asia.—In Europe the section is completely absent, except for three American species which occur as rare aliens. TheAxillares are not only morphologically well-characterized by their growth—no leaf rosettes, flowering period practically unlimited by formation of later flowering axillary shoots, flowers often monoecious—but also by their genetic structure expressed by a different behaviour in hybridization. Hybrids are frequent between species of sect.Rumex (syn.Simplices) and are easy to recognize by their sterility which results in a certain peculiarity in habit. In contrast, no spontaneous hybrids are known with certainty among species of sect.Axillares. Most artificial hybrids are fairly fertile. So far only three hybrids between species of the two sections have been known. Three more have been found by the author in Chile, all being highly sterile and showing the growth characteristics resulting from sterility as occur in hybrids between species of sect.Rumex.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 172 (1990), S. 263-271 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Commelinaceae ; Tradescantia soconuscana ; Zebrina ; Chromosome evolution ; Robertsonian change
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Meiotic pairing inTradescantia soconuscana 2n=26 (6M+16A+4T) suggests that it has a tetraploid constitution which is not apparent in its chromosome number. Its “nombre fondamental” of 32 indicates that it could have evolved from an ancestor with x=8 by a combination of Robertsonian fusion, hybridization and polyploidy. The 2n=16 (8A+8T) karyotype of a closely related diploid supports this. The allied genusZebrina may have followed a similar method of chromosome evolution.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 172 (1990), S. 229-240 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Mesembryanthemaceae ; Conophytum ; Floral morphology ; floral phenology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The complex floral structure in the southern African genusConophytum (Mesembryanthemaceae; 77 spp.) is described in detail and assigned to three basic floral types, two of which can be divided into two subtypes. Correlations between structural features and phenological patterns are demonstrated and discussed in the family context as well as in relation to the systematic subdivision of the genus.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 173 (1990), S. 1-15 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Geraniaceae ; Geranium ; Chemotaxonomy ; seed proteins ; essential oils ; nectar amino acids ; additivity in hybrids and allopolyploids ; chemical divergence and mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Relationships amongGeranium species constituting sectt.Anemonifolia, Lucida (monotypic) andRuberta together with representatives of sect.Unguiculata were investigated by gas-chromatographic study of essential oils, electrophoretic comparison of seed proteins and chromatographic separation of nectar amino acids. — Essential oil study gave little information.G. macrorrhizum (sect.Unguiculata) had far greater quantities of essential oils in its foliage than other species and differed from them qualitatively. — Species of sectt.Anemonifolia andRuberta, together withG. cataractarum (sect.Unguiculata), between them yielded 19 seed protein bands; the distribution of these indicated close relationship among the species and was consistent with hypotheses for the origin of certain species by alloand autopolyploidy partly within the group. Involvement of an unknown species in the origin of two allopolyploids was implied. Separate origins for the two octoploid species in this set are also inferred. In two instances there was evidence for the transformation of one band into another subsequent to the separation of related species. The inference of allopolyploidy was supported by the occurrence of additivity of parental bands shown by an artificial hybrid between two of the species. A model for the evolutionary divergence of the seed protein patterns is presented. Two species outside the above set appeared less closely related; they wereG. lucidum andG. macrorrhizum (sect.Unguiculata) and between them they showed 6 additional bands, four of which were shared. — Of 18 nectar amino acids found, 4 to 15 occurred in any one species, with low numbers (4 and 8) occurring in the most extreme inbreeders. The spectra of nectar amino acids of two hybrids showed additivity of those of the respective parents. The results echo rather closely those provided by seed proteins, but in the absence of data from outside the group their taxonomic significance is uncertain. However, the divergence between the two octoploids was again evident.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...