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  • Atomic, Molecular and Optical Physics  (2)
  • Oxalis tuberosa  (2)
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  • 1
    Electronic Resource
    Electronic Resource
    Expression of stylar incompatibility in the Andean clonal tuber crop oca (Oxalis tuberosa Mol., Oxalidaceae) (2000)
    Springer
    Sexual plant reproduction 13 (2000), S. 105-111 
    Details
    ISSN: 1432-2145
    Keywords: Key words Oca ; Oxalis tuberosa ; Floral heteromorphy ; Self-incompatibility ; Pollen fertility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Long-, mid-, and short-styled clonal accessions of oca (Oxalis tuberosa) were intercrossed in a complete diallelic design. Pollen tube growth in styles was monitored in all diallelic crosses. Pollen fertility was estimated by two tests: staining of pollen grains with aceto-carmine and detection of β-galactosidase activity by the substrate X-Gal. The two methods of pollen fertility estimation were equally useful to detect fertility levels. Pollen originating from short stamens had the highest fertility (85%) and pollen from long stamens had the lowest fertility (70%). Pollen fertility was high throughout, but its degree varied with the stylar morph on which the pollen was formed. Long-styled accessions had the highest rates of fertile pollen. Differences in pollen fertility at different anther levels in the same style morph were also apparent. Pollen grain diameter of the six morph-anther level combinations was inversely correlated with pollen fertility. Pollen grains from long stamens were the largest and pollen grains from short stamens were the smallest. Neither pollen fertility nor pollen grain size had an influence on pollen tube growth in the style or on fruit and seed set. Pollen tubes growing within the styles were inhibited at a different level for each of the 18 cross combinations in the diallel. Although legitimate crosses had greatest pollen tube growth, some of the illegitimate inter- and intramorph crosses had equally high scores. Of all illegitimate crosses, mid-styled seed parents had the lowest level of stylar incompatibility. Fruit and seed set were highly correlated with the extent of pollen tube growth in the style. The number of pollen tubes entering ovules in a flower was in good agreement with the number of seeds produced per fruit. Therefore, it is concluded that stylar incompatibility is the major determinant of limited seed formation in oca even in the most successful legitimate cross combinations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004970000040
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  • 2
    Electronic Resource
    Electronic Resource
    Germplasm conservation of oca (Oxalis tuberosa Mol.) through botanical seed. Seed formation under a system of polymorphic incompatibility (1998)
    Springer
    Euphytica 101 (1998), S. 133-141 
    Details
    ISSN: 1573-5060
    Keywords: Oxalis tuberosa ; oca ; reproductive biology ; breeding system ; tristyly ; genetic resources
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Seven clonal accessions representing all three stylar morphs of tristylous oca were intercrossed and selfed in a complete diallelic crossing design. The four traits total capsule production, total number of seeds/capsule, total number of seeds containing an embryo/capsule, and percent seeds containing an embryo of all seeds per capsule were recorded. Both capsule and seed production were highest in the legitimate pollinations (in which styles are pollinated with pollen of the corresponding anther level), but also in illegitimate pollinations of mid-styled seed parents with long-level anther pollen of short-styled accessions. All 18 types of pollination, consisting of 6 legitimate, 6 illegitimate intermorph, and 6 illegitimate intramorph pollinations, expressed gradually different levels of capsule and seed production. Intramorph pollinations and selfs of mid-styled seed parents were less incompatible than intramorph pollinations and selfs of the long- and short-styled morphs. All accessions studied expressed an intact system of heteromorphic stylar incompatibility despite their exclusive clonal propagation for millennia. A maximum of 16,3 seeds/capsule containing an embryo was obtained in an individual legitimate cross of two accessions, although an average of 25 ovules are present in a flower of O. tuberosa. The results are discussed in relation to the establishment of a genebank based on botanical seed of this clonally propagated, valuable Andean tuber crop.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018336003573
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  • 3
    Electronic Resource
    Electronic Resource
    Löwdin partitioning in a Lanczos basis: Applications to scattering states (1983)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 23 (1983), S. 135-146 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methods are reported for construction of closed-form optical potentials that provide useful L2-basis-set approximations to the discrete and continuum Schrödinger states of self-adjoint Hamiltonian operators. The potentials are obtained employing information from a finite (Lanczos) reference space only, but nevertheless correspond to explicit summation over an infinite-dimensional remainder space. Connections are indicated between the Stieltjes-Tchebycheff orbital solutions of the resulting optical-potential Schrödinger problem and previously described corresponding moment-theory approximations to spectral densities and distributions. Use of a Lanczos basis insures that the orbital eigenvalues are generalized Gaussian or Radau quadrature points of the spectral density, and that their (reciprocal) norms provide the associated quadrature weights. Convergence of the orbitals in the limit of high order is obtained to Schrödinger eigenstates of finite norm in the discrete spectral region, and to scattering states of improper (infinite) norm in the essential portion of the spectrum. In finite orders the spatial characteristics of the Stieltjes-Tchebycheff orbitals correspond to spectral averages in the neighborhoods of the quadrature points over the correct Schrödinger states. Explicit closed-form expressions are obtained for the spectral content of individual orbitals in terms of orthogonal polynomials without reference to the correct Schrödinger states. A computational application to regular Coulomb l waves illustrates the nature and convergence of the development.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560230115
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  • 4
    Electronic Resource
    Electronic Resource
    Stieltjes orbitals for molecular photoexcitation and ionization spectra: N → Vσ and N → V π resonance features in CO and H2CO cross sections (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 719-734 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Computational studies are reported of Stieltjes orbitals for Hilbert-space descriptions of discrete and continuum molecular electronic eigenstates. Particular attention is focused on the identification of N → V π(π → π*) and N → Vσ(σ → σ*) intravalence contributions to photoexcitation and ionization spectra in CO and H2CO molecules. Three-dimensional graphical representations of appropriate Stielties orbitals serve to identify the σ → σ* transitions of Mulliken as photoionization resonances above threshold in these compounds, whereas the corresponding π → π* contributions are spectrally localized as familiar discrete excited states. The development illustrates the nature and properties of Stieltjes orbitals, and demonstrates their utility in studies of both discrete and continuum excitation spectra on a common basis.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260864
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