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  • Angiosperms  (132)
  • Drosophila  (116)
  • 42.60  (90)
  • Springer  (338)
  • American Chemical Society (ACS)
  • 1980-1984  (338)
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  • 1
    ISSN: 1432-0649
    Keywords: 32.80 ; 42.60 ; 6.30
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The velocity distribution of evaporated Zr atoms has been measured by means of laser-induced fluorescence using a cw dye laser by scanning the laser line across the Doppler-broadened absorption line profile of the atoms. It is shown that the experimental data can be explained on the basis of an excitation theory for a three-level system developed from basic principles. It was calculated that the probability for an atom to be in the excited state mainly depends on the radiation-power density of the laser and on the residence time of the atom in the exciting laser light. It was found that the laser frequency must be well stabilized in order to meet the assumptions in the excitation calculation. Otherwise deviations to the theoretical predictions appear in the experimental results due to the jitter of the dye laser.
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  • 2
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    Applied physics 35 (1984), S. 123-126 
    ISSN: 1432-0649
    Keywords: 42.50 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Spatial separation of wavelengths in a CO2-laser resonator helps to avoid competitions. We have achieved this by means of a nearly concentric resonator with a grating or prism in its center. Thus, we demonstrated independent multiline emission with a variety of output spectra. The temporal sequence of the lines was conveniently controlled by varying their losses.
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  • 3
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    Applied physics 33 (1984), S. 23-27 
    ISSN: 1432-0649
    Keywords: 42.55 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract For the first time stable cw output of a FIR-CO2 hybrid laser has been achieved at wavelengths shorter than 300 μm. Due to the saturable absorber characteristic of the FIR laser gas, cw or pulsed emission is observed on both, the CO2 and the FIR laser output, depending on the operating conditions. Results are reported on different resonant lines in CH3OH and the 67 μm Raman line in NH3. The good efficiency of this laser is also demonstrated by the excitation of two new emission lines in CH3OH, namely 49 and 56 μm, pumped by 9R(22) and 9R(24), respectively.
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  • 4
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    Applied physics 33 (1984), S. 57-61 
    ISSN: 1432-0649
    Keywords: 33 ; 42.60 ; 82.50
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A laser photodesorption microscope has been applied to obtain 4×103-fold images of rhodamine crystals on a tip with a diameter of 66μm. Peculiarities of the formation of these images have been studied with different values of electric field strength on the tip and laser pulse intensities.
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  • 5
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    Applied physics 33 (1984), S. 179-185 
    ISSN: 1432-0649
    Keywords: 06 ; 07.60 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We describe a study, performed using heterodyne techniques, of the frequency fluctuations of two completely independent ring dye lasers locked to independent reference cavities. Single laser linewidths of less than 750 Hz were achieved, the principal limitation being residual vibrations from the noisy laboratory environment. With future design and environmental improvements, ultranarrow linewidths are expected thus providing a useful tool for a great variety of high precision experiments.
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  • 6
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    Applied physics 33 (1984), S. 213-218 
    ISSN: 1432-0649
    Keywords: 35 ; 82.40 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract CARS spectra of NH3 and the free NH2-radical in the NH stretch region at 3334 and 3220 cm−1 have been obtained, respectively. The NH2 radicals were generated by laser photolysis of 0.5 mbar NH3 at 193 nm with an ArF-exciplex laser and detected by time resolved CARS spectroscopy.
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  • 7
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    Applied physics 34 (1984), S. 63-67 
    ISSN: 1432-0649
    Keywords: 06 ; 07.60 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An infrared frequency measurement chain is reported, the simplicity of which allows phase-coherent frequency measurements up to 30 THz. Frequency measurement is demonstrated on the 10P(28) line of the Lamb-dip stabilized13CO2-laser.
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  • 8
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    Applied physics 34 (1984), S. 129-137 
    ISSN: 1432-0649
    Keywords: 33.50 ; 42.10 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A theoretical description of a three-pulse transient grating technique is given where the pump pulses form orientational gratings. Including energy relaxation and angular reorientation the temporal behavior of the diffraction efficiency and energy transmission is discussed with respect to the dependence on the corresponding rate constants and the results are compared with experimental data for Rh6G and RhB. The polarization plane of the pulse diffracted by the grating is found to be rotated in dependence on its initial polarization.
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  • 9
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    Applied physics 35 (1984), S. 163-166 
    ISSN: 1432-0649
    Keywords: 42.50 ; 42.55 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present an analytical expression for the small-signal gain of a Free Electron Laser (FEL) in the presence of a Gaussian mode. To describe the electron beam evolution we use the one-dimensional (1-d) Vlasov equation. Our perturbation result, valid for small values of the parameterq (length of the undulatorL divided by the Rayleigh rangeZ R), can be extrapolated to values ofq≈4÷5.
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  • 10
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    Applied physics 33 (1984), S. 63-74 
    ISSN: 1432-0649
    Keywords: 42.60 ; 78.30 ; 78.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract This review covers the field of vapor-phase dye lasers (VPDL) with special emphasis on prospects of gas lasers with optical pumping. Some peculiarities of the gaseous active medium and a possibility to control its density near the critical point are discussed. High specific laser energies (∼0.3J/cm−3), low thresholds, and high efficiencies (20–40%) made it possible to construct a powerful tunable VPDL.
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  • 11
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    Applied physics 33 (1984), S. 103-113 
    ISSN: 1432-0649
    Keywords: 42.68 ; 42.80 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A long-path absorption procedure for the determination of tropospheric OH concentrations is described in detail. Initial measurements using this method were carried out in Frankfurt a. M. By including in the evaluation the visible radiation of a frequencydoubled dye laser used in the measurements, it was possible to mathematically reduce the signal fluctuations caused by the scattering and density fluctuations of tropospheric air. The resulting detection limit was 3×106 OH per cm3. SO2 concentrations which had to be simultaneously determined in order to eliminate an interference effect, could be detected in the range of 1–40 ppb on the absorption path.
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  • 12
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    Applied physics 33 (1984), S. 9-16 
    ISSN: 1432-0649
    Keywords: 42.60 ; 42.20 ; 42.55
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We derive the most general equations of motion for the electrons and the electromagnetic field in a free-electron laser including the effects of diffraction and pulse propagation. The field evolution is expressed in terms of the amplitudes and phases of a complete set of transverse modes. The analytic solution is given in the small-signal regime, where the theory is shown to be in excellent agreement with a recent experiment at Orsay.
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  • 13
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    Applied physics 33 (1984), S. 83-90 
    ISSN: 1432-0649
    Keywords: 82.50 ; 82.40 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Tritium isotope separation by CO2-laser induced multiphoton dissociation of CTF3 is investigated. For the optimization of the performance of this working substance, trifluoromethane, the conditions to yield high-selectivity at high-operating pressure and low-critical fluence for complete dissociation are studied using our deconvolution procedure. The irradiation conditions are varied over the following ranges; wavenumber: 1052–1087 cm−1, gas temperature: 25°C to −78°C, CHF3 pressure: 5–205 Torr. The selectivities exceeding 104 are observed for 85–205 Torr CHF3 at −78°C by the irradiation at 1057 cm−1.
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  • 14
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    Applied physics 34 (1984), S. 29-31 
    ISSN: 1432-0649
    Keywords: 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Directional and wavelength sweep of a pulse train from a distributed-feedback dye laser is studied and found not to be a thermal effect, rather a gain-induced one. The directional sweep can be used for single-pulse selection.
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  • 15
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    Applied physics 35 (1984), S. 71-75 
    ISSN: 1432-0649
    Keywords: 42.60 ; 42.55 ; 42.72
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A simple model of the energy transfer between a booster dye and the active dye in a flashlamp pumped planar waveguide dye laser is described. Analytical results are compared with experiments for several dyes in the 600–650 nm region. A twofold increase of laser output was found at a wavelength (630 nm) which is of particular interest for several applications.
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  • 16
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    Applied physics 35 (1984), S. 119-122 
    ISSN: 1432-0649
    Keywords: 42.72 ; 42.80 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The output of a CO2 laser, operating on theP I(18) transition of13C16O2 at 26941 GHz (11.128 μm) was phase-locked to a 5 MHz signal from a primary Cs frequency standard by means of a frequency chain having only CO2 lasers as infrared sources. Simultaneously, four other CO2 lasers in the chain were phase-locked to the 26941 GHz output. This provided CO2 laser frequencies at 26 450 305, 26 940 815, 28 694 625, 29 442 480, and 33 185 715 MHz having zero long-term-average frequency error relative to the Cs standard, and the ±10−13 (≃3 Hz) long-term absolute uncertainty of the standard.
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  • 17
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    Applied physics 33 (1984), S. 187-193 
    ISSN: 1432-0649
    Keywords: 42.50 ; 42.55 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract It is shown by numerical analysis based on Lamb's equations of motion, that standing-wave lasers with purely homogeneously broadened emission lines exhibit regular multimode oscillations. Specifically, modes lying far from the line centre are quenched due to mode competition, and the amplitudes of the oscillating modes approach steady-state values. The stabilization of the amplitudes is normally accompanied, or followed, by an evolution of the phases towards a phase-locked regime, where the relative phasesψ n = 2φ n −φ n + 1 −φ n − 1 [φ n phase in then th mode, defined by (6)] attain either the value 0 or ± π. The build-up times for the relative phases are found to vary over a wide range.
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  • 18
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    Applied physics 33 (1984), S. 219-223 
    ISSN: 1432-0649
    Keywords: 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We describe the generation of excimer-laser pulses of 〈10 ps pulse width and up to 40 mJ pulse energy at 248.5 nm and their use in the measurement of ps gain dynamics in a KrF amplifier. Small-signal gain of 〉2×104, saturation energy density of 2.0 mJ/cm2, and gain recovery time of 4 ns were measured. In contrast to XeCl* no short-gain rcovery time was found in KrF* and the stored inversion could be fully depleted bya single ps pulse.
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  • 19
    ISSN: 1432-0649
    Keywords: 42.68 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An analysis of 532 nm lidar data is presented for the retrieval of vertical extinction profiles. The strong influence of the relative humidity on the extinction-to-backscatter ratio is parametrized for this purpose. A comparison is made between remotely sensed and locally measured extinction coefficients, using reference values in aircraft and at ground level.
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  • 20
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    Applied physics 34 (1984), S. 191-192 
    ISSN: 1432-0649
    Keywords: 42.55 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A pulsed xenon ion laser has been used to pump a rhodamine 6G dye laser utilizing a ring resonator. The dye laser has been passively mode-locked; a pulsewidth of 0.5 ps and a 50 kW peak power have been obtained.
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  • 21
    ISSN: 1432-0649
    Keywords: 42.80 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The values of the chopping disc slot and mark space widths relative to the radius of the Gaussian beam are found, which achieve optimum harmonic-like and efficient amplitude modulation of the cw laser beam. The simple approximation for the waveform of the modulated laser power valid for these optimum or near optimum values of the chopping disc parameters is presented.
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  • 22
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    Applied physics 33 (1984), S. 17-21 
    ISSN: 1432-0649
    Keywords: 52.00 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A comparison of the operating characteristics of the high-voltage regime of the discharge in a hollow-cathode tube, the hollow-canthode discharge (HCD) and the discharge to a plane cathode are presented. The disappearnce of the hollow-cathode effect and the transition to a high-voltage discharge after inserting several anode rods into the cathode cylinder is exhibited. The similarity between the operating characteristics of such a high-voltage discharge and of a plane cathode discharge is shown. The loss of ions at the anode rods, as well at insulators or floating conductors is believed to be the reason behind the increase of the operating voltage and the disappearance of HCD characteristics. Practical means of increasing the operating voltage are mentioned.
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  • 23
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    Applied physics 33 (1984), S. 75-77 
    ISSN: 1432-0649
    Keywords: 42.30 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We report upon some experiments done on a continuous-wave argon-ion laser which offers 300 W output power in the visible and 34 W in the ultraviolet region of the spectrum, limited by the degradation of the resonator mirrors. To avoid destruction of the outcoupling mirror, a folded three-mirror instead of a two-mirror cavity was tried, resulting in nearly the same output power.
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  • 24
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    Applied physics 33 (1984), S. 95-98 
    ISSN: 1432-0649
    Keywords: 42.60
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    Topics: Physics
    Notes: Abstract Generation of single dye laser pulses of 12 ps pulse width (FWHM) and 1.2 mJ pulse energy is described using only one XeCl-excimer laser as pump source. At 1 Hz pulse repetition rate the stability of amplitude and pulse width of these pulses is excellent.
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  • 25
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    Applied physics 35 (1984), S. 233-236 
    ISSN: 1432-0649
    Keywords: 42.60 ; 07.77 ; 34.50
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The effect of resonant laser-light upon a charge-exchange source of eV-range sodium atoms is to decrease the Na kinetic energy by about 2 eV. The mechanism probably involves a reduction of the space charge in the low-energy ion precursors. The reduction is caused by electrons created in collisional ionization of laser-excited atoms. This is related to the well-known optogalvanic effect. A knowledge of the existence of this effect can be important for the design of experiments involving laser driven chemistry.
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  • 26
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    Applied physics 35 (1984), S. 199-200 
    ISSN: 1432-0649
    Keywords: 42.60 ; 07.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We report results of harmonic mixing experiments between millimetric oscillators and FIR laser radiations up to 3 THz, using micrometer-size Schottky-barrier diodes. Signal-to-noise ratios suitable for precise frequency counting have been obtained for harmonic numbers up to 40.
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  • 27
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    Applied physics 35 (1984), S. 227-231 
    ISSN: 1432-0649
    Keywords: 42.55 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The feasibility of using the electrically excited XeF(C»A) excimer medium as an efficient wideband amplifier in the blue-green region of the spectrum has been investigated. Calculations show that for an intense blue-green optical flux input the amplification characteristics of XeF(C»A) improve, as a result of both bleaching of the pump induced absorbers and by additional production of XeF(C) level population. The removal of one of the major absorbing species, Xe** in the XeF (C»A) laser mixture by means of a pulsed ruby laser probe beam has been demonstrated.
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  • 28
    ISSN: 1432-0649
    Keywords: 42.60 ; 42.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We report the observation of coherent uv emission at 330.2±0.5 nm when sodium vapor in a heatpipe is irradiated with a pulsed visible dye laser with output wavelength in the 570–595 nm region. It is found that intense uv emission can be produced from Na atoms as well as from Na2 molecules. The excitation functions and their dependence on vapor density and laser power density are presented and the mechanisms for producing the emission are discussed.
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  • 29
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    Journal of molecular evolution 20 (1984), S. 251-264 
    ISSN: 1432-1432
    Keywords: Drosophila ; Genome evolution ; 68C Glue gene cluster ; Drosophila melanogaster species subgroup
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The 68C puff is a highly transcribed region of theDrosophila melanogaster salivary gland polytene chromosomes. Three different classes of messenger RNA originate in a 5000-bp region in the puff; each class is translated to one of the salivary gland glue proteins sgs-3, sgs-7, or sgs-8. These messenger RNA classes are coordinately controlled, with each RNA appearing in the third larval instar and disappearing at the time of puparium formation. Their disappearance is initiated by the action of the steroid hormone ecdysterone. In the work reported here, we studied evolution of this hormone-regulated gene cluster in themelanogaster species subgroup ofDrosophila. Genome blot hybridization experiments showed that five other species of this subgroup have DNA sequences that hybridize toD. melanogaster 68C sequences, and that these sequences are divided into a highly conserved region, which does not contain the glue genes, and an extraordinarily diverged region, which does. Molecular cloning of this DNA fromD. simulans, D. erecta, D. yakuba, andD. teissieri confirmed the division of the region into a slowly and a rapidly evolving protion, and also showed that the rapidly evolving region of each species codes for third instar larval salivary gland RNAs homologous to theD. melanogaster glue mRNAs. The highly conserved region is at least 13,000 bp long, and is not known to code for any RNAs.
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  • 30
    ISSN: 1432-0649
    Keywords: 42.60 ; 42.55
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    Topics: Physics
    Notes: Abstract To improve the gain in the Orsay storage ring Free Electron Laser (FEL) experiment, the 17 period permanent magnet undulator has been modified to form an optical klystron (OK). We report the measurement of spontaneous emission and the effects on it of energy spread and angular spread. Gain and laser induced bunch lengthening measurements with the OK are also reported and are in very good agreement with the FEL classical theory. The spontaneous emission spectrum which is easy to measure with good signal to noise ratio, turns out to be a very good diagnostic tool forenergy spread and angular spread measurements on storage rings. The factor of four increase in the small gain obtained by converting the undulator NOEL into an OK was the critical factor in the recent operation of the ACO storage ring laser above threshold.
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  • 31
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    Applied physics 35 (1984), S. 31-36 
    ISSN: 1432-0649
    Keywords: 42.60 ; 33 ; 36
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A spectroscopic dye laser system-pumped by a Copper Vapor Laser (CVL)-has been built and optimized for different dye solutions operating in the spectral range from 530 to 890 nm. Conversion efficiencies up to 40% were reached in broad band operation, 24% with a prism expander grating cavity, and 20% in grazing incidence configuration, which operated at typical band widths of 3 GHz. Second harmonic generation (SHG) of the dye laser output produced tunable uv-radiation between 260 and 408 nm at conversion efficiencies ≦5%. Fundamental and SHG output were used for resonant ionization experiments in molecular beams.
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  • 32
    ISSN: 1432-0630
    Keywords: 42.60 ; 68.55 ; 61.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract New results are reported concerning the vanadium oxidation by cw CO2 laser irradiation in air at atmospheric pressure. Particular emphasis is paid both to the initial stage and the development of the oxidation process under the action of the laser radiation. Some aspects are finally discussed concerning the quantitative theoretical interpretation of the experimentally recorded data.
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  • 33
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    Development genes and evolution 193 (1984), S. 267-282 
    ISSN: 1432-041X
    Keywords: Drosophila ; Larval cuticle ; Pattern formation ; Embryonic lethal mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In a search for embryonic lethal mutants on the second chromosome ofDrosophila melanogaster, 5764 balanced lines isogenic for an ethyl methane sulfonate (EMS)-treatedcn bw sp chromosome were established. Of these lines, 4217 carried one or more newly induced lethal mutations corresponding to a total of 7600 lethal hits. Eggs were collected from lethal-bearing lines and unhatched embryos from the lines in which 25% or more of the embryos did not hatch (2843 lines) were dechorionated, fixed, cleared and scored under the compound microscope for abnormalities of the larval cuticle. A total of 272 mutants were isolated with phenotypes unequivocally distinguishable from wild-type embryos on the basis of the cuticular pattern. In complementation tests performed between mutants with similar phenotype, 48 loci were identified by more than one allele, the average being 5.4 alleles per locus. Complementation of all other mutants was shown by 13 mutants. Members of the complementation groups were mapped by recombination analysis. No clustering of loci with similar phenotypes was apparent. From the distribution of the allele frequencies and the rate of discovery of new loci, it was estimated that the 61 loci represent the majority of embryonic lethal loci on the second chromosome yielding phenotypes recognizable in the larval cuticle.
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  • 34
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    Development genes and evolution 193 (1984), S. 90-97 
    ISSN: 1432-041X
    Keywords: Drosophila ; Temperature-sensitive ; Neoplasms ; Differentiation ; Imaginal discs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary EMS induced temperature-sensitivelethal (2) giant larva, 1(2)gl, alleles were isolated by screening against a knownl(2)gl allele. Analysis of the lethal phase of thel(2)gl ts-deficiency heterozygotes demonstrated: (1) the majority of thel(2)gl tslarvae survive to late third instar, (2) at 29°C the majority of thel(2)gl tslarvae failed to pupate and only rarely did they differentiate adult cuticular structures, (3) at 15°C the majority of the larvae pupated and frequently differentiated adult cuticular structures. Examination of the imaginal discs ofl(2)gl tslarvae reared at 29°C revealed the presence of morphologically abnormal wing, haltere and leg imaginal discs. No morphologically abnormal discs were found in thel(2)gl tslarvae reared at 15°C. Studies on both the histology and the developmental capacity of the morphologically normal and abnormall(2)gl tsdiscs were performed. The morphologically normal discs are histologically normal and produce a full complement of adult cuticular structures. However, the morphologically abnormal discs contained both regions that maintained the normal monolayer epithelium and regions that had lost the normal tissue architecture. The implants obtained when the morphologically abnormal discs are injected into metamorphosing larvae contained only a limited number of the normal complement of adult structures and usually only structures found in the ventral wing hinge region were recovered. In addition, the “metamorphosed” morphologically abnormal discs contained undifferentiated tissue that gave rise to transplantable neoplasms when cultured in adults. The results of the studies on the pathology of thel(2)gl tslarvae are discussed with respect to the role of thel(2)gl tsfunction during normal development, the autonomy of the neoplastic development of thel(2)gl tstissues, and similarities between neoplastic development inDrosophila and mammals.
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  • 35
    ISSN: 1432-041X
    Keywords: Drosophila ; Pole cell transplantation ; Heterospecific combinations ; Gametogenesis ; Chorion morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We transplanted pole cells betweenDrosophila melanogaster, D. mauritiana andD. ananassae to investigate the ability of germ cells to develop in the gonad of a heterospecific host, and to study the interaction between somatic follicle cells and the cells of the germ line in producing the species-specific chorion. FemaleD. mauritiana germ cells in aD. melanogaster ovary produced functional eggs with normal development potential. The same is true for the reciprocal combination. FemaleD. ananassae pole cells in aD. melanogaster host only developed to a very early stage and degenerated afterwards. None of the interspecific combinations of male pole cells led to functional sperm. We could not determine at what stage the transplanted male pole cells were arrested. The cooperation of follicle cells and the oocyte-nurse cell complex in producing the chorion was studied using the germ-line-dependent mutationfs(1) K10 ofD. melanogaster, which causes fused respiratory appendages and an abnormal chorion morphology. Wild-type femaleD. mauritiana germ cells in a mutantfs(1) K10 D. melanogaster ovary led to the production of wild-type eggs withD. melanogaster-specific, short respiratory appendages. On the other hand,D. melanogaster fs(1) K10 germ cells in aD. mauritiana ovary induced the formation of eggs with mutant fused appendages which were, however, typicallyD. mauritiana in length. When.D. mauritiana pole cells developed in aD. melanogaster ovary, the chorion exhibited a new imprint pattern that differs from both species-specific patterns.
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    Development genes and evolution 193 (1984), S. 98-107 
    ISSN: 1432-041X
    Keywords: Drosophila ; Neoplasms ; Promotion ; Regeneration ; Temperature-sensitive ; Imaginal discs
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    Topics: Biology
    Notes: Summary In this paper we present an analysis of the behavior ofl(2)gl tsimaginal wing discs during culture in adult hosts. Thel(2)gl tslarvae reared at 29° C contain two types of wing discs, those that are morphologically normal and those that are abnormal. When discs of both types are cultured in adult hosts at 29° C, the restrictive temperature, they give rise to transplantable neoplastic tissue. However, when the 29° C reared discs are cultured at 15° C, the permissive temperature, the morphologically normal discs maintain their morphology, but the morphologically abnormal discs give rise to neoplasms. Thel(2)gl tslarvae reared at 15° C contain only morphologically normal discs. When these discs are cultured in adult hosts at 29° C they give rise to neoplasms, however if the discs are cultured at 15° C they maintain their normal morphology. These results demonstrate: (1) that all wing imaginal discs obtained from 29° C rearedl(2)gl tslarvae are competent to undergo neoplastic development, (2) the morphologically abnormal discs obtained from the 29° C rearedl(2)gl tslarvae are committed to neoplastic development, (3) the neoplastic development of the morphologically normal discs is temperature dependent, (4) once the neoplastic development of thel(2)gl tsdiscs has been initiated the process is not readily reversible. In addition, the ability ofl(2)gl tswing discs to perform epimorphic regulation was tested by amputating morphologically normal permissively rearedl(2)gl tswing discs and culturing both fragiments at the permissive temperature. Fragments of control wild-type discs maintained their morphology during culture at the permissive temperature. However, both fragments of txel(2)gl tsdiscs became neoplastic. This result is discussed with respect to a possible role for thel(2)gl +function in epimorphic regulation and with respect to the phenomena of tumor promotion in vertebrates.
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  • 37
    ISSN: 1432-041X
    Keywords: Drosophila ; Gap junction ; Imaginal disc ; Pattern formation ; EM Stereology
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    Topics: Biology
    Notes: Summary Developmental changes in the distribution of gap junctions in early, mid and late third larval stage wing discs and in pupariation+6 h and pupariation+24 h stage wing discs fromDrosophila melanogaster were analyzed by quantitative electron microscopy. Gap junctions occur in all 12 intradisc regions examined in each of the five developmental stages. Their distribution is non-random and changes during development which suggests that they are developmentally regulated. The gap junctions are not static structures, rather they grow and regress during development. The changes tend to be gradual ones without sudden increases or decreases. Gap junctions continuously form and grow in size throughout the third larval stage and during the first 6 h following pupariation. Their surface density, number, percent of the lateral plasma membrane area, and absolute area as well as the lateral plasma membrane surface density all increase during this time. Between pupariation+ 6 h and pupariation+24 h all but one of these parameters decrease indicative of gap junctional breakdown. Gap junctions are most numerous and change least during development in the apical cell regions where intercellular contacts are close and stable. They change most in the basal cell regions where intercellular contacts tend to be looser and change during development. The most dramatic change is in the absolute area which increases by a factor of 23 between the early third larval stage and pupariation+24 h. At pupariation the rate of gap junction growth undergoes a transient increase before the phase of disassembly begins. Developmental changes in gap junction surface density are closely coupled with changes in the lateral plasma membrane surface density which suggests that these may be coregulated. Evidence from mutants suggests that when the number and density of gap junctions fail to increase in proportion to lateral plasma membrane growth, wing disc development will be abnormal. Our results support the idea that some minimum gap junction density is required for normal development and that this must increase as development proceeds. The results are consistent with the notion that gap junctions are involved in pattern formation and growth control and are discussed with respect to the acquisition of competence for metamorphosis, disc growth, disc morphogenesis and changes in the hormonal environment.
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    Development genes and evolution 193 (1984), S. 296-307 
    ISSN: 1432-041X
    Keywords: Drosophila ; Larval cuticle ; Pattern formation ; Embryonic lethal mutations
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    Topics: Biology
    Notes: Summary In order to identify X-chromosomal genes required inDrosophila for early patterning and morphogenesis, we examined embryos hemizygous for EMS-induced lethal mutations to determine which of those mutations cause gross morphological defects. Embryos from 2711 lethal lines, corresponding to 3255 lethal point mutations were studied. Only 21% caused death during embryogenesis and of these, only one-sixth, or 3% of the total lethals, were associated with defects visible in the final cuticle pattern. Of the 114 point mutants causing visible cuticle defects, 76 could be assigned to 14 complementation groups. An additional 25 mutations mapping to regions of the X-chromosome not covered by male fertile duplications were assigned to six complementation groups based on similarities of map position and phenotype. Thirteen mutations could not be assigned to complementation groups. All mutations allowed normal development through the cellular blastoderm stage, the first defects associated with the earliest acting loci being observed shortly after the onset of gastrulation. The phenotypes of the various loci range from alterations in segment pattern or early morphogenetic movements to defects in final pigmentation and denticle morphology. Cuticle preparations were also examined for 63 deletions spanning in total 74% of the X-chromosome, as well as for 8 deletions and point mutations derived in saturation mutagenesis screens of the fourth chromosome (Hochman 1976). With the exception of defects in head morphology and defects in cuticle differentiation, none of the hemizygous deletions showed phenotypes other than those predicted by point mutations known to lie in those regions. No deletion caused new or unknown alterations in gastrulation, segmentation or cuticle pattern.These results suggest that the number of genes required zygotically for normal embryonic patterning is small and that most, if not all such loci, are represented by point mutations in our collection.
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  • 39
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal disc ; Morphogenesis ; Tissue culture
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    Topics: Biology
    Notes: Summary The thin region of the peripodial membrane is confined to the area overlying the distal anlagen in thoracic discs. During the early stages of evagination the peripodial membrane is greatly stretched, but does not rupture. The appendage then evaginates through the stalk, probably by means of a contraction of the peripodial membrane. The cells of the peripodial membrane of leg and wing discs persist and differentiate sheets of trichomes characteristic of the ventral and lateral thorax. This is discussed in relation to imaginal disc fate maps.
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    Development genes and evolution 193 (1984), S. 263-265 
    ISSN: 1432-041X
    Keywords: Drosophila ; Biothorax complex ; Prothoracic transformation
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    Topics: Biology
    Notes: Summary If, early in development, theUbx + gene is removed by mitotic recombination from cells of the meso-and metathoracic leg primordia, theseUbx − cells develop as in the posterior prothoracic leg. We show that this transformation, termedpostprothorax, is a discrete genetic function that is independent of other homeotic transformations such asbx, pbx orbxd, which also result from the inactivation of theUbx gene.
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    Development genes and evolution 193 (1984), S. 283-295 
    ISSN: 1432-041X
    Keywords: Drosophila ; Larval cuticle ; Pattern formation ; Embryonic lethal mutations
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    Topics: Biology
    Notes: Summary The present report describes the recovery and genetic characterization of mutant alleles at zygotic loci on the third chromosome ofDrosophila melanogaster which alter the morphology of the larval cuticle. We derived 12600 single lines from ethyl methane sulfonate (EMS)-treatedst e orrucuca chromosomes and assayed them for embryonic lethal mutations by estimating hatch rates of egg collections. About 7100 of these lines yielded at least a quarter of unhatched eggs and were then scored for embryonic phenotypes. Through microscopic examination of unhatched eggs 1772 lines corresponding to 24% of all lethal hits were classified as embryonic lethal. In 198 lines (2.7% of all lethal hits), mutant embryos showed distinct abnormalities of the larval cuticle. These embryonic visible mutants define 45 loci by complementation analysis. For 32 loci, more than one mutant allele was recovered, with an average of 5.8 alleles per locus. Complementation of all other mutants was shown by 13 mutants. The genes were localized on the genetic map by recombination analysis, as well as cytologically by complementation analysis with deficiencies. They appear to be randomly distributed along the chromosome. Allele frequencies and comparisons with deficiency phenotypes indicate that the 45 loci represent most, if not all, zygotic loci on the third chromosome, where lack of function recognizably affects the morphology of the larval cuticle.
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    Development genes and evolution 193 (1984), S. 308-325 
    ISSN: 1432-041X
    Keywords: Neurogenesis ; Pattern of neuroblasts ; Drosophila
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    Topics: Biology
    Notes: Summary This paper deals with morphological aspects of early neurogenesis inDrosophila, in particular with the segregation of neuroblasts from the neurogenic region of the ectoderm and the pattern formed by those wells within both the germ band and the procephalic lobe. The neurogenic ectoderm was found to contain neural precursors intermingled with epidermal precursors, extending from the midline up to the primordia of the tracheal tree along the germ band and laterodorsally in the procephalic lobe. Germ band neuroblasts segregate from the neurogenic ectoderm during a period of several hours according to characteristic spatial and temporal patterns. During the first half of the segregation process the pattern of germ band neuroblasts was found to be the same in different animals in both spatial arrangement and number of cells; this permitted the identification of individual neuroblasts from different embryos. Later in development several difficulties were encountered which precluded an exact description of the neuroblast pattern. The constitution of the neurogenic region is discussed in relation to the phenotype of mutants affecting neurogenesis.
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    Development genes and evolution 193 (1984), S. 388-393 
    ISSN: 1432-041X
    Keywords: Drosophila ; Oogenesis ; Ring canals ; Oocyte determination ; Polarity
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    Notes: Summary The pattern of intercellular connections between germ line cells has been studied in follicles of the mutantdicephalic (dic), which possess nurse cell clusters at both poles. Staining of follicles with a fluorescent rhodamine conjugate of phalloidin reveals ring canals and cell membranes and thus allows us to reconstruct the spatial organization of the follicle. Each germ line cell can be identified by the pattern of cell-cell connections which reflect the mitotic history of individual cells in the 16-cell cluster. The results indicate that in both wild-type anddicephalic cystocyte clusters one of the two cells with four ring canals normally becomes the pro-oocyte. However, in some follicles (dicephalic and wild-type) oocytes were found with fewer or more than four ring canals. Indic follicles, one or several nurse cells may become disconnected from the other cells during oocyte growth at stage 9–10. Such disconnected cells cannot later on empty their cytoplasm into the oocyte. This, in turn, might be of consequence for the determination of axial polarity of the embryo.
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    Development genes and evolution 193 (1984), S. 406-413 
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal disc ; Morphogenesis ; Tissue culture
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    Topics: Biology
    Notes: Summary The fusion of the eye-antennal discs during culturein vitro has been investigated, and the complex morphogenetic movements which occur during the formation of the head capsule of the insect are described. The initial contact between the eye anlagen is by means of cell processes spanning the gap between the two discs. Subsequently the two epithelia become firmly apposed, and then the integrity of the epithelium in the region of fusion breaks down, cells appearing to move to new positions in order to form an epithelium which unites the two discs. The epithelium eventually secretes a pattern of cuticular structures which is continuous between the derivatives of the two discs. Bristles on either side of the line of fusion are perfectly aligned, and structures such as the median ocellus, which are formed jointly by the cells of the two discs, differentiate normally. This is also found when left and right eye-antennal discs of different genotypes are placed side-by-side, indicating that processes of pattern regulation can occur in culture.
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    Biochemical genetics 22 (1984), S. 153-168 
    ISSN: 1573-4927
    Keywords: alcohol dehydrogenase ; Drosophila ; activity ratio ; specific activity
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Thirteen Drosophila Adh variants have been characterized with respect to gene expression, substrate preference, thermostability, and specific activity. The results suggest that the variants may be grouped into two biochemical classes, typified by the properties of the two most common enzyme forms, ADH-F and ADH-S. Membership of these classes cannot be predicted from electrophoretic mobility, nor is any simple classification possible with regard to the characteristics of level of gene expression (in terms of ADH activity or ADH protein) or thermostability of the gene product.
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    Biochemical genetics 22 (1984), S. 1015-1029 
    ISSN: 1573-4927
    Keywords: acetaldehyde ; alcohol dehydrogenase ; aldehyde oxidase ; Drosophila
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Metabolic utilization and toxicity of acetaldehyde were studied in flies lacking alcohol dehydrogenase (ADH), aldehyde oxidase (AO), or both functions. Prior to the experiments, mutant alleles Adh n4 and mal were transferred to the same genetic background by 10 successive backcrosses. By comparison with wild-type flies, various deleterious, pleiotropic effects could be attributed to the mal allele but not to Adh n4 . Of the four genotypes studied (mal, Adh n4 , mal Adh n4 , and wild), all were able to use acetaldehyde as a resource in a similar way. In spite of its high toxicity, acetaldehyde appeared a better resource than ethanol. Flies treated with intermediate acetaldehyde concentrations (around 0.5%) exhibited a very high interindividual heterogeneity which could reflect a physiological adaptation occurring as a consequence of the aldehyde treatment. Toxicity tests showed that ADH-negative flies were more sensitive to acetaldehyde than wild type, but this is most likely explained by the transformation of the aldehyde into alcohol. Our results show that the aldehyde metabolizing enzyme (AME) system in Drosophila is neither ADH nor AO. The existence of an aldehyde dehydrogenase is plausible.
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    Behavior genetics 14 (1984), S. 279-293 
    ISSN: 1573-3297
    Keywords: phototaxis ; Drosophila ; correlated response ; selection ; sepia
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    Topics: Biology , Psychology
    Notes: Abstract Artificial selection for positive and negative phototaxis was conducted in populations ofDrosophila melanogaster that were polymorphic at thesepia locus. Photoselection response was accompanied by a correlated response in the frequency of thesepia allele. Changes insepia frequency were shown to be significantly different from those predicted by several neutral models. Implications of this correlated response are briefly discussed in terms of the neurogenetic basis of phototaxis.
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    Behavior genetics 14 (1984), S. 315-317 
    ISSN: 1573-3297
    Keywords: Drosophila ; mating and barometric pressure
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    Topics: Biology , Psychology
    Notes: Abstract During a study ofDrosophila mating behavior we observed unexpected changes in performance under ostensibly identical experimental conditions. We related the behavior during the 17 days of the experiment to changes in ambient humidity and barometric pressure. Humidity had no significant effect, but reduced barometric pressure was found to be associated with reduced mating activity (R 2=0.29,P〈0.025), accounting for close to 30% of the variation in total number of matings.
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  • 49
    ISSN: 1573-3297
    Keywords: Drosophila ; courtship ; learning ; circadian
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    Behavior genetics 14 (1984), S. 411-440 
    ISSN: 1573-3297
    Keywords: Drosophila ; courtship ; pheromones
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    Behavior genetics 14 (1984), S. 527-557 
    ISSN: 1573-3297
    Keywords: Drosophila ; learning ; classical conditioning mutants ; cAMP
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    Behavior genetics 14 (1984), S. 441-478 
    ISSN: 1573-3297
    Keywords: Drosophila ; courtship ; pheromones
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    Topics: Biology , Psychology
    Notes: Summary Experimental evidence and speculation relative to chemical messages exchanged byDrosophila during courtship and mating are reviewed. Only the speciesD. melanogaster andD. simulans are considered in detail. Emphasis is put on female aphrodisiacs, as they clearly participate in sex and species recognition. All the aphrodisiac molecules described are unsaturated long-chain hydrocarbons, and position 7 for a double bond seems important in both species. InD. melanogaster, only females are able to make 7,11-dienes, compounds which stimulate males of this species to court. InD. simulans, 7-tricosene plays a similar role but is produced by both sexes as well as maleD. melanogaster. In both species, polymorphism is shown for these molecules. Their biosynthesis is also considered and both preliminary biochemical and genetic data are introduced. Male-specific compounds which regulate male and female behaviors are also reviewed. For example,cis-vaccenyl acetate inhibits male courtship; one or two peptides control the female's receptivity and egg laying. Such compounds are transferred from males to females together with sperm.
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  • 53
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    Keywords: assortative mating ; polymorphism ; partner selection ; pheromone ; behavior ; Drosophila
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    Notes: Abstract Averhoff and Richardson [(1974)Behav. Genet. 4:207–225] reported a trend toward negative assortative mating inDrosophila melanogaster during the course of inbreeding. These authors proposed that the underlying mechanism was based on pheromone polymorphism and male selection. Mass mating experiments were carried out to verify their hypothesis, detailed behavior observations were made to identify the underlying mechanism, and sex pheromone composition and variation were examined by using gas chromatography-mass spectrometry analysis. The results showed that negative assortative mating is not a general phenomenon. Although male pheromones are probably polymorphic, female pheromones are not. We found no evidence for male selection as predicted by Averhoff and Richardson. It is argued that the most parsimonious mechanism underlying negative assortative mating is similar to one proposed by Bryant [(1979)Behav. Genet. 9:249–256], which was based on interstrain differences in female reluctancy and male vigor.
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    Behavior genetics 14 (1984), S. 153-156 
    ISSN: 1573-3297
    Keywords: mating behavior ; statistical analysis ; Drosophila
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    Topics: Biology , Psychology
    Notes: Abstract Quite different sets of data are shown to generate identical output ratios so that analyses of mating behavior data based on the use of input and output ratios may obscure significant aspects of the mating behavior.
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  • 55
    ISSN: 1573-3297
    Keywords: Drosophila ; learning ; conditioning
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    Plant systematics and evolution 144 (1984), S. 59-66 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Araceae ; Hapaline ; Hapale ; Phymatarum ; Bucephalandra ; Flora of Borneo ; East Malaysia ; Sarawak
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract On the basis of newly collected and cultivated material full descriptions and illustrations are presented forHapaline appendiculata Ridl. andPhymatarum borneense M. Hotta.
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    Plant systematics and evolution 144 (1984), S. 67-71 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Scrophulariaceae ; Veronica fridericae spec. nova ; V. acrotheca ; V. farinosa ; V. armena ; V. multifida ; V. jacquinii ; V. caucasica ; V. filifolia ; V. oltensis ; Flora of Turkey
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    Notes: Abstract Veronica fridericae spec. nova, described from the type locality in the S.E. Turkish province Van, is related toV. acrotheca andV. farinosa, both endemic to W. Iran. All 8 perennial species with pinnatifid leaves in S.W. Asia are presented in a key.
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    Plant systematics and evolution 144 (1984), S. 149-150 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Campanulaceae ; Campanula schimaniana spec. nova ; Flora of Afghanistan and of Pakistan
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    Topics: Biology
    Notes: Abstract Campanula schimaniana is a new species of sect.Campanula subsect.Rupestres, distributed in the westernmost mountains affected by monsoon.
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    Plant systematics and evolution 144 (1984), S. 151-153 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Asteraceae-Heliantheae ; Calea ; Chromosome numbers ; polyploidy
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    Topics: Biology
    Notes: Abstract Chromosome numbers are reported for six taxa ofCalea, among them tetraploidC. septuplinervia, the only known polyploid inCalea s. str. The base chromosome number ofCalea is interpreted as x = 19.
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    Plant systematics and evolution 144 (1984), S. 155-163 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Leguminosae ; Fabaceae ; Caesalpinioideae ; Mimosoideae ; Faboideae ; Phaseolus coccineus ; Serological systematics ; seed proteins ; phytohaemagglutinin ; vicilin ; phaseolin
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    Notes: Abstract An immunosystematical research was conducted on the seed proteins of 32 species ofFabaceae. By comparing all immunelectrophoretic patterns with the self reaction of a reference system (Phaseolus coccineus) all proteins detected have been identified and their distribution within the family has been analyzed. Half of the proteins identified inP. coccineus gave positive cross reactions with proteins present in all other species. Among this group are “protein I” and “phaseolin”. This result supports the homologization between phaseolin and vicilin. Among the other proteins, three are irregularly distributed throughout the family, and only three are restricted to a few taxa. This last group includes phytohaemagglutinin, which does not present any cross reaction outside the tribePhaseoleae.
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    Plant systematics and evolution 144 (1984), S. 209-220 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Triticum ; Elytrigia ; wheat ; Evolution ; genome ; karyotype
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    Notes: Abstract The lengths of the A, B, and D genomes of common wheat,Triticum aestivum, were measured from the karyotype. Relative to the B genome, standardized as length 1.000, the lengths of the A and D genomes were 0.835 and 0.722, respectively. The lengths of the chromosome arms in the A and D genomes were then multiplied by the appropriate constants so that the total lengths of each genome also equalled 1.000. These calculations revealed that homoeologous chromosomes in wheat, with a few exceptions, have similar sizes and arm ratios. The arm lengths of the three homoeologues in each homoeologous group were then averaged. These average chromosomes turned out to be remarkably similar, in size and arm ratio, to their homoeologues in the E genome ofElytrigia elongata. This evidence and data on cross-compatibility and morphological characteristics suggested that the genusTriticum is a result of adaptive radiation from the perennial genusElytrigia, specifically from the complex of species possessing the E genome or one closely related to it.
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    Plant systematics and evolution 144 (1984), S. 307-314 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Geraniaceae ; Erodium ; Monsonia ; Geranium ; Taxonomic revision ; Flora of Egypt
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    Topics: Biology
    Notes: Abstract A key is provided for the 14Erodium species of the Egyptian flora. The important differential chracters of leaf, inflorescence, flower, and fruit are discussed and illustrated.
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    Plant systematics and evolution 144 (1984), S. 315-320 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Fabaceae ; Lupinus palaestinus ; L. pilosus ; Breeding system ; insect induced self pollination
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    Notes: Abstract Significant increase of pod production occurs inLupinus palaestinus Boiss. andL. pilosus Murr. following insect visits. The cause of this increase is investigated through (1) examination of the biology of pollination, (2) examination of pod production under various pollination conditions, (3) examination of cross pollination by genetical markers. All data strongly suggest that “Insect Induced Self Pollination” is the main factor in the increase of pod production of these species in nature.
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    Plant systematics and evolution 145 (1984), S. 1-13 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Triticum aestivum ; Aegilops longissima ; Cytogenetics ; homoeologous relationships ; chromosome substitutions ; translocations
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    Notes: Abstract The relationships of three wheat-Aegilops longissima chromosome addition lines A, C, and D with homoeologous wheat chromosomes were studied in PMC meiosis. Substitutions of alien chromosome A for wheat chromosome 6 B, chromosome C for 1 B and chromosome D for 4 B were obtained. The production of 4 BS/C and 7 BS/D chromosome translocations indicated cytogenetic relationships of C partially to homoeologous wheat chromosomes of group 1 and 4, and D partially to homoeologous wheat chromosomes of group 4 and 7.
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    Plant systematics and evolution 145 (1984), S. 15-28 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Gramineae ; Hordeum spontaneum ; Wild gene pool ; factor analysis ; numerical taxonomy
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    Notes: Abstract Samples from 11 populations of wild barley,Hordeum spontaneum, from Israel, were examined for morphological variation in a “common garden” plot design. Earliness traits had the highest between population variation of all traits studied. No relationship was found between dimensions of leaves and size of seeds.—Using numerical taxonomy methods, four races were found, which correspond to the geographical and environmental range of the species in Israel. It is concluded thatH. spontaneum shows a well developed tendency toward formation of highly adaptive races rather than exhibiting clinical variation.
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  • 66
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    Keywords: Angiosperms ; Annonaceae ; Porcelia goyazensis ; Annona reticulata ; Winteraceae ; Drimys brasiliensis ; Giemsa C-banding ; structural heterozygosity ; karyotype evolution in tropical woody plants
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    Notes: Abstract InPorcelia goyazensis (2n = 18) Giemsa C-banding patterns differ from those ofAnnona reticulata (2n = 14) and reveal structural heterozygosity. The amplitude of karyological variation in theAnnonaceae is greater than expected for a “primitive” woody family. In a comparison with other tropical angiosperm groups, the highly differentiated karyotype ofDrimys brasiliensis (2n = 86) is interpreted as being the end-point of numerous karyological changes.
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    Plant systematics and evolution 145 (1984), S. 55-77 
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    Keywords: Angiosperms ; Acanthaceae ; Bignoniaceae ; Bombacaceae ; Caesalpiniaceae ; Caryocaraceae ; Chrysobalanaceae ; Fabaceae ; Lobeliaceae ; Lythraceae ; Malvaceae ; Marcgraviaceae ; Mimosaceae ; Musaceae ; Onagraceae ; Orchidaceae ; Passifloraceae ; Proteaceae ; Rubiaceae ; Solanaceae ; Tiliaceae ; Zingiberaceae ; Flower nectar ; amino acids ; sugars ; evolutionary significance ; pollination biology
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    Notes: Abstract Individual amino acids and sugars from flower nectar of 32 plant species with different pollination systems were quantified and compared. Data show that there is no correlation between sugar and amino acid concentration. Furthermore there is no correlation between composition and concentration of amino acids and evolutionary advancement, nor any direct relation with pollination systems. However, higher sugar concentrations are often linked with more advanced morphological characters. Nectars from pierced or damaged flowers or nectars contaminated with pollen exhibit modifications and increases in amino acid composition. The presence of proline probably indicates such pollen contamination. Most pollinating animals depend on flower nectar in their energetic requirements, yet innumerable alternative amino acid and protein sources exist. Future research has to consider the relationship between nutritional requirements of pollinating animals and dependence on flower nectars.
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    Plant systematics and evolution 145 (1984), S. 135-153 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteraceae ; Senecio vulgaris ; S. vernalis ; Autotetraploidy ; self-compatibility ; annual weeds
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    Topics: Biology
    Notes: Abstract Senecio vulgaris L. (2n = 40) is suggested to be of autotetraploid origin fromS. vernalis Waldst. & Kit. (2n = 20). This conclusion is based on results obtained from experimental hybridisations and cytological observations, and the consideration of morphological affinities, patterns of geographical distribution and hybrid formation under natural conditions. The morphological differences between the two species are related to a difference in the breeding system. WhilstS. vernalis is self-incompatible,S. vulgaris is self-compatible and strongly self-pollinating. Equally, other self-pollinating taxa traditionally associated withS. vulgaris are shown to have evolved independently from outbreeding relatives. Within a narrow frame of relationship, annual weeds have evolved in different cytotaxonomic circumstances.
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    Plant systematics and evolution 145 (1984), S. 165-168 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Solanaceae ; Datura innoxia ; Haploidy ; diploidy ; triploidy ; tetraploidy ; hexaploidy ; amino acid composition
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    Notes: Abstract In haploid, diploid, triploid, tetraploid and hexaploid cytotypes of the scopalamine-yieldingDatura innoxia, the amino acid profiles were studied. The results suggest that the amino acid composition is influenced quantitatively by increasing ploidy levels, but in an irregular way.
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    Plant systematics and evolution 145 (1984), S. 183-191 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Saxifragales ; Cunoniales ; Brunelliaceae ; Brunellia comocladiifolia ; B. mexicana ; Theales ; Caryocaraceae ; Caryocar brasiliense ; C. microcarpum ; C. villosum ; Karyosystematics ; paleopolyploidy ; tropical woody plants
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    Notes: Abstract Chromosome numbers are polyploid, 2n = 28 inBrunellia comocladiifolia andB. mexicana, and 2n = 46 inCaryocar brasiliense, C. microcarpum andC. villosum. The chromosome are small in both genera, with a length of ca. 1,6-0,4µm. Interphase nuclei correspond to the prochromosomal and the chromocentric type, respectively. This is in conformance with the systematic placement ofBrunelliaceae intoCunoniales, and ofCaryocaraceae intoTheales. Brunellia exhibits affinities to various other orders ofRosidae (andHamamelididae), and is suggested to be primarily apetalous. On a comparative basis, the chromosome numbers found in both families are interpreted as paleopolyploid (4 x and 6 x). This apparently is in correspondence with their rather primitive features, systematic isolation, relatively depauperate status, and evidently great age.
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    Plant systematics and evolution 145 (1984), S. 193-201 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Ranunculaceae ; Aconitum ; Seed morphology ; seed coat SEM microcharacteristics ; taxonomic importance ; adaptative ecological significance
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    Notes: Abstract The seed coat morphology, investigated in taxa representative of the main European groups ofAconitum, are in good agreement with the current taxonomy of the genus. The seed coat microcharacteristics (warty epidermal cells) are very constant. There is a trend for the reduction of longitudinal wings on the edges concomitant with the development of ridges and transverse wings on the faces. Another morphological progression leads from smooth to rugulose and eventually to transverse wing-bearing seed faces. A working hypothesis suggests an ecological adaptative significance to these changes.
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    Plant systematics and evolution 145 (1984), S. 223-226 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Theaceae ; Camellia japonica ; Allozymes ; polyploidy ; origin of cultivars
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    Notes: Abstract Electrophoretic examination of allozymes from 189Camellia japonica cultivars revealed some banding patterns not explainable by codominant diploid genetics. At several loci encoding dimeric enzymes, 5 and 6 banded patterns were observed in 7 cultivars. These patterns are interpreted as resulting from triploidy or aneuploidy, where three variant alleles code for products which are electrophoretically distinguishable and associate to form three homodimers and three heterodimers. The presence of allozyme multiplicity in these clones suggests a sexual rather than a somatic mode of triploid origin.
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    Plant systematics and evolution 145 (1984), S. 243-258 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteraceae ; Lactuceae ; Microseris ; Canalized numbers ; additive polygenes ; evolutionary genetics ; pappus parts ; leaf shape ; isoenzymes
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    Notes: Abstract CrossingMicroseris pygmaea (10 pappus parts) withM. bigelovii (5 pappus parts) results in hybrids with variable pappus part numbers between 5 and 10. Previous work has shown that a system of four additively acting genes determines the average pappus part numbers of these hybrids. In hybrid B87 two genes have a 10-determining and a 5-determining allele each, two others a 5-determining and a null (inactive or missing) allele. Genetic linkage of one of the latter with the enzyme geneEsterase-1 and the leaf shape genespatulate leaves has been demonstrated. Here we demonstrate linkage between one of the two 10-determining genes and the enzyme locusEsterase- Y/B. The genotypes in the pappus part system of many specimens can now be fully determined. This is a major advance for the analysis of the evolution of this additive polygenic system.
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  • 74
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    Keywords: Angiosperms ; Caryophyllaceae ; Silene latifolia ; S. alba ; S. pratensis ; Geographic variation ; racial differentiation ; clines ; morphological variation ; flavone glycosylation genes ; principal components analysis ; cluster analysis ; Flora of Europe
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Abstract Morphological and biochemical data were analysed from 30 greenhouse-grown populations of EuropeanSilene latifolia. Six separate character sets (flavones, seed, pollen, capsules, male and female flower morphology) were used in the analyses. There was broad-scale congruence between trends of geographic variation in most character sets, with the populations being assigned to western (or southern and western) and eastern clusters. The eastern and western clusters abut along a transition zone that runs roughly from Belgium to the northern Balkans; this zone represents a region of relatively rapid change and contains populations intermediate between the eastern and western clusters. Variation in flower morphology was weak and discordant with variation in the other character sets. The origin and maintenance of the variation pattern is discussed in terms of migrational history and “hybrid zones”.
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    Plant systematics and evolution 145 (1984), S. 291-309 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Cruciferae ; Brassicaceae ; Biscutella variegata complex ; B. laevigata complex ; Chromosome numbers ; variation ; aneuploidy and polyploidy ; chromosomal imbalance ; protogyny ; inbreeders and outbreeders
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    Notes: Abstract Chromosome counts were determined for 46 populations ofBiscutella representing 28 taxa. The genus was found to contain diploid taxa with 2n = 12, 16 and 18, tetraploid taxa with 2n = 36 and hexaploid taxa having 2n = 54.B. laevigata L. s. l. consists of diploid and tetraploid populations which are poorly differentiated morphologically. TetraploidB. laevigata s. l. and hexaploidB. variegata Boiss. & Reuter (s. l.) are characterized by chromosomal instability. The variation in chromosome numbers and the occurrence of polyploidy is discussed in relation to the taxonomy of the genus. An investigation of the breeding system showed that most of the annual species were self-compatible and partly inbreeding and most of the perennial species self-incompatible and, therefore, outbreeding, while one annual species,B. cichoriifolia Loisel., showed both systems.
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    Plant systematics and evolution 146 (1984), S. 1-11 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Liliaceae ; Hyacinthaceae ; Scilla peruviana ; Gene mapping ; restriction enzymes ; ribosomal RNA genes ; rRNA/DNA hybridization ; polyploidy
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    Notes: Abstract Scilla peruviana biotypes have different chromosome numbers due to changes in the nucleolar chromosomes and polyploidy. We have examined two diploid (2n = 15 and 2n = 16) and two tetraploid biotypes (2n = 28 and 2n = 32). From the results of rRNA/DNA filter hybridizations it appears that rDNA percentages of the diploid biotypes are, approximately, 2.2-fold higher than those of the tetraploid biotypes. To examine the rRNA gene structure we have utilizedSouthern blot hybridization after DNA digestions with three restriction enzymes: Eco RI, Hind III and Bam HI. From the band analysis of both single and double digestions it has been possible to reveal the presence, in the diploid biotypes, of three gene types, heterogeneous both for length and for nucleotide sequences in the external spacer. The three rRNA genes are 12 600, 12 700, and 12 800 base pairs long and they have a different position of the Hind III sites in the external spacer. On the other hand, a single gene type of 12 600 base pairs, identical to the first type of the diploid biotypes, surprisingly exists in the tetraploid biotypes. Considerations on the rRNA gene regulation and evolution are made.
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    Plant systematics and evolution 146 (1984), S. 13-30 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Rutaceae ; Chromosome number ; karyotaxonomy ; base number ; karyotype variation ; literature critique
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    Notes: Abstract Detailed chromosome counts have been made in 61 species, belonging to 33 genera ofRutaceae. 30 of these species are reported here for the first time. For 18 species at least one previous publication gives a chromosome number differing from that reported here. Such discrepancies are, in most cases, due to errors in counting or identification of the material. By critically reviewing the literature on each particular case, it appears possible to eliminate most of the false data. On the basis of the present results, the base number x = 10 is proposed for the genusRuta.
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    Plant systematics and evolution 146 (1984), S. 47-55 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Annonaceae ; Chromosomes ; polyploidy ; karyosystematics ; cytotaxonomy
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    Notes: Abstract Information and illustrations on somatic chromosomes, structure of interphase nuclei and hair development are presented for 9 genera and 14 species ofAnnonaceae. A few suggestions tend to improve the unsatisfactory current classification. The spectrum of polyploids found in the family ranges from neo- to meso- and paleopolyploids.
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    Plant systematics and evolution 146 (1984), S. 87-104 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Iridaceae ; Sisyrinchieae ; Tigridieae ; Trimezieae ; Basic numbers ; chromosome size ; karyotypes ; polyploidy ; karyotypic asymmetry ; bimodality ; DNA increase ; chromosome evolution
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    Notes: Abstract Although the South AmericanIridaceae are cytologically diverse, three tribes are distinguishable on the basis of karyotype morphology. TheSisyrinchieae andTrimezieae have variable basic numbers, ploidy levels and chromosome sizes, while theTigridieae are characterized by a relatively uniform basic number and bimodal karyotype. Changes in chromosome size within genera may suggest fluctuations in their DNA amount with latitude and altitude, particularly inSisyrinchium. The results are considered in terms of opportunities for more detailed research.
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    Plant systematics and evolution 146 (1984), S. 117-121 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Embryology ; megagametophyte ; antipodals proliferation
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    Notes: Abstract The structure of the grasses megagametophyte is considered to be characteristic enough as to deserve a particular place in the megagametophyte typology. Furthermore, it is compared with those of other Monocotyledonous families to point out embryological affinities.
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    Plant systematics and evolution 146 (1984), S. 105-116 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Myrtales ; Oliniaceae ; Olinia ; Embryology ; reproductive anatomy ; systematics
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    Notes: Abstract Two of the five species ofOliniaceae (Olinia emarginata andO. ventosa), a monotypic and problematic family of theMyrtales, were investigated embryologically.Oliniaceae clearly agree with otherMyrtales in their basic embryological characteristics, and are characterized further by having an ephemeral endothecium, a campylotropous ovule, and a thick, three-five-layered, outer integument. A combination of these three characteristic features is unknown elsewhere inMyrtales, so that embryological features do not support a close relationship with any other member of the order. Shared distinctive anther characteristics (i.e. ephemeral endothecium) suggest thatOliniaceae are derived from the common ancestor ofCrypteroniaceae s. str.,Rhynchocalycaceae, Alzateaceae, andPenaeaceae.
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    Plant systematics and evolution 146 (1984), S. 141-143 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Lamiaceae ; Salvia tuxtlensis spec. nova ; Flora of Mexico
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    Notes: Abstract Salvia tuxtlensis, sp. n., is immediately recognized by its semipersistent bracts and yellow flowers. Its affinities are not clear. It is endemic to the Soteapan area in the Sierra de Los Tuxtlas, in Veracruz, Mexico.
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    Plant systematics and evolution 146 (1984), S. 123-139 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Boraginaceae ; Rochelia ; Rochelia disperma ; Gynoecial development ; fruit development ; pseudomonomery ; systematics ; evolutionary trends
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    Notes: Abstract The ontogeny of the gynoecium ofRochelia disperma has been investigated by LM and SEM. From the floral apex only one carpel primordium arises abaxially and eventually shifts into a subterminal position. Neither an initial stadium of a second carpel nor an adaxial vascular strand in gynobase and style could be observed. InR. stylaris two vascular strands run through the style and two undifferentiated lobes in adaxial position may be regarded as rudimentary mericarps. Only from comparison with related taxa the conclusion can be drawn thatRochelia is really pseudomonomerous, more so inR. disperma than inR. stylaris. The primary gynoecial bulge splits up into three parts inR. disperma: style/stigma, nutlets with gynobase, and disc. While the mericarps originate in mostBoraginoideae from the symplicate region and the ascidiate one is restricted to the very basal parts, inR. disperma the ascidiate part extends and forms the nutlets. The hood-shaped mouth of the carpel (the plicate zone) is closed to a triangular slit in lateral position, the stigma. The nutlets are triangular with broad base and do not surround the adaxial part of the gynobase inR. disperma, R. persica, R. bungei, R. stylaris, andR. macrocalyx. In contrast,R. peduncularis, R. cardiosepala, andR. cancellata have nutlets clasping the gynobase; they may be more closely related than was assumed up to now. The glochids ofRochelia are fascicled unicellular hairs (with different shapes) and not emergences as in theCynoglosseae. There is an evolutionary trend towards fruit formation with only one mericarp, especially inR. disperma.
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    Plant systematics and evolution 146 (1984), S. 171-179 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Rosaceae ; Fragaria ; Restitution ; microsporogenesis ; polyploidy ; evolution
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    Notes: Abstract Double restitution has been observed cytologically for the first time in microsporogenesis of a F1 hybridFragaria virginiana ×F. chiloensis ♂. Restitution is probably due to irregularities affecting the spindle mechanism. Single or double restitution may depend upon the duration of the effect or upon the stage of meiosis affected. The occurrence of triades is indicative of a possible intracellular diversity. Although the reason which may cause restitution remains to be ascertained, maternal inheritance indicates an extrachromosomal cause.
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    Plant systematics and evolution 146 (1984), S. 181-195 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Myrtales ; Penaeaceae ; Penaea ; Saltera ; Embryology ; reproductive anatomy ; systematics
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    Notes: Abstract Two species ofPenaeaceae (Penaea mucronata andSaltera sarcocolla), a unique South African family ofMyrtales, were investigated embryologically.Penaeaceae clearly agrees with otherMyrtales in its basic embryological characteristics, and further is characterized by its highly specialized features: ephemeral endothecium, 16-nucleatePenaea-type embryo sac, and unique ovular form. A wider range of affinities of families includingPenaeaceae, Oliniaceae, Rhynchocalycaceae, Alzateaceae, andCrypteroniaceae sensu stricto, as well as a possible common divergence from an ancestral line leading toLythraceae and/orMelastomataceae, are discussed on embryological and other grounds.
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    Plant systematics and evolution 146 (1984), S. 197-214 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Cactaceae ; Epidermis ; parallelocytic stomata ; stomatal types ; classification ; survey
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    Notes: Abstract The stomatal types (i.e. the arrangement of epidermal cells in the vicinity of a stomatal pore in superficial view) have been examined in more than 150 taxa ofCactaceae, mostly using documented material. Preparations have been made by mazerating pieces of tissue with modified Jeffrey's Solution and staining with chlore-zinc-jodine.—The examined members of the subfamilyCactoideae showed parallelocytic stomata with only minor deviations in a number of cases. Members of the subfamiliesPereskioideae andOpuntioideae show parallelocytic stomata on the leaves, but the stomatas of the stem represent a different type, which apparently is not yet described. It is termed opuntioid here. In most cases the stomata are superficial but a few taxa show markedly sunken or “hidden” stomata.—In taxa of the subfamiliesPereskioideae andOpuntioideae the stomata are generally oriented parallel to the stem axis with only minor deviations. The stomata of taxa of the subfamilyCactoideae do in general not show a particular orientation with the notable exception of a number of epiphytic genera from the tribeHylocereeae.—The results of these investigations in general coincide well with the generic classification of theCactaceae byHunt (1967). A few cases where stomatal characters suggest a differing classification merit further investigations.—Additionally, the possibilities to distinguish between paracytic and parallelocytic stomata are discussed and an amended definition for the latter is given.
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    Plant systematics and evolution 146 (1984), S. 265-267 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Loranthaceae ; Phthirusa adunca ; Anther wall ; endothecial thickenings
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    Topics: Biology
    Notes: Abstract The thickenings in the anther wall ofPhthirusa adunca are confined to the endothecium. This observation resembles the previous report onP. pyrifolia.
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    Plant systematics and evolution 146 (1984), S. 225-248 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Scrophulariaceae ; Campanulaceae ; Canarina ; Isoplexis ; Bird pollination ; ornithophily ; Flora of Macaronesia ; Canary Islands
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    Topics: Biology
    Notes: Abstract (1) On the Canary Islands and Madeira typical bird-flowers occur in at least twelve species of six genera, although true flower-birds are absent. This inconsistency is in part elucidated by field observations on exotic and wild plants of Tenerife. —(2) In the Botanical Garden of Orotava it could be observed that various ornithophilous plants, which were introduced there, were visited by indigenous birds for nectar and in one case (Orthostemon) for food tissue. Of the three bird species involved, an endemic race of Chiffchaff (Phylloscopus collybita) and resident Blackcaps (Sylvia atricapilla) exploit, and pollinate, flowers legitimously, while the Wild Canary (Serinus canaria) is predominantly a destructive nectar robber. —(3) The insular Chiffchaff also proved to be a regular pollinator in the wild, at least ofCanarina canariensis andIsoplexis canariensis, two ornithophilous paleoendemics. Ornithophily, thus, is naturally practised on the island, though by birds basically insectivorous. —(4) A list of Macaronesian plants bearing the more or less complete ornithophilous syndrome is presented, including newly recognizedTeucrium heterophyllum andScrophularia calliantha. —(5) On biogeographical and faunistic grounds it is presumed that the modern visitors of Canarian bird flowers are secondary rather than the original partners of the continental tertiary flora in which these plants originated. Palearctic immigrants, when becoming resident on the islands during and since the Pleistocene, adopted facultative nectar feeding, entering an “orphaned” food niche. Casual flower visits in Europe suggest a certain predisposition of the Chiffchaff and the Blackcap for the exploitation of flowers. — (6) The ability of unspecialized birds to acquire nectardrinking spontaneously and to pass this habit on to their offspring, is demonstrated by a population of Tree Sparrows (Passer montanus) which have visited ornithophilousKniphofia (Liliaceae) in Berlin for several years.
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    Plant systematics and evolution 147 (1984), S. 1-27 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Gramineae ; Dispersal ; hygroscopic movements ; trypanocarpy ; diaspore ecology ; cerrado vegetation ; Flora of Brazil
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    Topics: Biology
    Notes: Abstract 28 grass species from one hectare of cerrado vegetation in Botucatu, State of São Paulo, were studied with regard to the morphology and dispersal of their fruits. 13 species have dispersal units with smooth surfaces which are predominantly dispersed by big herbivorous mammals or birds which swallow them together with their food, e.g., during grazing (accidental endozoochory). On the other hand, smaller animals, including birds, also feed directly on the grains; some of them may escape trituration and digestion or may be even stored (synzoochory). 11 species are principally epizoochorous: 8 of these are ± exclusively adapted to epizoochory, adhering to the animals by scabrid awns or sharply pointed calli, while the rest behave as epizoochores and anemochores. 4 other species are predominantly anemochorous with their dispersal units bearing soft hairs, sometimes together with very small scabrid awns; in a wet state they also can adhere to animals (occasional epizoochory). Beside this, most grass fruits can behave as passive ballists, as passing animals, wind and rain may cause their dispersal units to fall to the ground (passive autochory). — Among the 28 species, 12 have dispersal units which are awned. In 7 of them the awns are spirally twisted; the base of the dispersal unit runs out into a sharply pointed callus and has harpoone-like hairs. These awns show hygroscopical movements which may lead to a drilling of the basal part of the dispersal unit into the sandy cerrado soil. This trypanocarpy is important for establishment but without function for dispersal.
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    Plant systematics and evolution 147 (1984), S. 55-61 
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    Keywords: Angiosperms ; Bombacaceae ; Malvaceae ; Hampea nutricia ; Seed morphology and anatomy ; aril
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    Notes: Abstract The mature seeds ofHampea nutricia are glabrous, ovoid, arillate and dark tan in colour. Longitudinal streaks on the seed surface correspond to the underlying integumentary vascular strands. Testa and tegmen are derived from the outer and inner integuments, respectively. The outer epidermis of the tegmen forms a palisade-like macrosclereid layer, the inner epidermis a fringe layer. The endosperm is single-layered and also fills the space between the two cotyledons. The embryo is nearly straight, gland-dotted; it has asymmetrical and folded cotyledons, and gossypol ducts. Systematic position ofHampea is discussed and its placement inMalvaceae is supported.
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  • 91
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    Plant systematics and evolution 147 (1984), S. 63-78 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Exine morphology ; origin of sporophytic self-incompatibility ; palynology ; pollen wall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In angiosperm pollen the reticulate-perforate exine sculpturing is associated with sporophytic self-incompatibility (S.S.I.) and imperforate and microperforate exine sculpturing is associated with gametophytic self-incompatibility. The earliest unequivocal angiosperm pollen conforms to exine morphology of pollen from plants with S.S.I. The orgin of S.S.I. is hypothesized to have coincided with the appearance of what is now the earliest recognizable angiosperm pollen. Other angiosperm characteristics correlated with S.I., functional stigmatic areas, large showy flowers (or aggregated inflorescences), and passive seed dispersal, provide some insight into the biological aspects of the earliest angiosperms.
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  • 92
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    Plant systematics and evolution 147 (1984), S. 79-90 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Onagraceae ; Oenothera hookeri ; Oe. suaveolens ; Megasporogenesis ; inheritance of callose pattern and polarity of embryo sac development ; embryology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The pattern of callose formation in meiotic cell walls and the order of megaspore degeneration and polarity during embryo sac development are investigated in F2-plants ofOe. hookeri ×suaveolens and the reciprocal cross. All investigated characters are variable between the ovules in the same ovary. Plants differ in the frequency of the types of callose pattern and polarity of the embryo sacs. In segregating progenies different combinations of both characters are found. The genetic basis of the polarity phenomena during the embryo sac development is discussed. In our material no correlation can be seen between the callose pattern in the surrounding wall of the meiotic cell and the development of polarity in the later stages.
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  • 93
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    Plant systematics and evolution 147 (1984), S. 103-118 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Limonium ; Plumbaginaceae ; Numerical taxonomy ; variation ; agamospermy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A taxometric analysis ofLimonium species in Western Europe has provided evidence for the subgeneric groupings proposed by other authors. A cluster analysis suggests that the origin of sexual and agamospermous species has taken place separately. Sexual and agamospermous species are usually clustered separately. The lack of a sexual process in many agamospermous species, as indicated by the distribution of incompatibility morphs and by very low pollen fertility, suggests that the evolution of sexual and agamospermous taxa has been by different processes. It is suggested that following the origin of agamospermous species or species groups by hybridisation, subsequent evolution in the agamospermous taxa has occurred by asexual means. Evidence from the distribution of pollen/stigma incompatibility morphs, especially the existence of self-compatible agamospermous species supports this hypothesis.
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  • 94
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    Plant systematics and evolution 147 (1984), S. 91-102 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Onagraceae ; Clarkia xantiana ; Electrophoresis ; isozymes ; phylogenetic models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Electrophoretic variation in isozymes coded by 40 loci was examined in two self-pollinating populations, one with white and the other with pink flowering plants, and four outcrossing populations ofClarkia xantiana (Onagraceae) native to California. The study was carried out to test theMoore & Lewis (1965) hypothesis that the pink selfer originated from the sympatric outcrossing population and then gave rise to the white selfer. The hypothesis could be rejected if one or the other selfer was more similar genetically to an allopatric population than to the sympatric one. Both selfers were monomorphic at all loci whereas the outcrossing populations were polymorphic at nearly half of them. The two selfers had the same genes at 32 loci but had different ones at eight loci. The pink selfer was not more similar to the allopatric populations than to the sympatric one, consistent with theMoore & Lewis model. The evidence also supported their proposal that the white selfer originated from the pink one and not independently. The electrophoretic evidence was valuable because it permitted qualitative comparisons (presence versus absence of particular alleles) between the selfer and the several outcrossing populations; such analysis was not previously possible because the latter populations are morphologically and cytologically similar.
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  • 95
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    Plant systematics and evolution 147 (1984), S. 119-123 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Melastomataceae ; Nodal and petiolar vascularization ; common gap and split laterals ; flank bridge ; cortical bundles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The nodal anatomy inMelastomataceae is variable. The (two times) unilacunar one trace type is wide-spread. In addition, species ofHeterocentron and ofTribouchina exhibit one pair of common gaps with split laterals. Others possess a distinct “flank bridge” of vascular tissue. Species with internodes quadrangular and four-winged in transsect exhibit up to five concentric cortical bundles per wing; they are involved in both petiolar vascularization and formation of flank bridges.
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  • 96
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    Plant systematics and evolution 147 (1984), S. 125-131 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Betulaceae ; Betula ; Alnus ; Carpinus ; Corylus ; Wood anatomy ; vascular tracheids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The occurrence of vascular tracheids inBetula, Alnus, Carpinus andCorylus is reported. It is established that the cells are a consistent feature in early and late wood where they are associated with vessel elements in radial multiples. The possible function and taxonomic importance of these cells are briefly considered.
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  • 97
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    Plant systematics and evolution 147 (1984), S. 167-175 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Saxifragaceae ; Bergenia cordifolia ; Gynoecium ontogenesis ; meristem incorporation ; meristem fusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Scanning electron microscopical investigations of flower buds of the perennial herbBergenia cordifolia (Haw.)A. Br. (Saxifragaceae) reveal a primitive gynoecium. During ontogenesis the margins of the carpel lamina transgress on the apical cone of the axis by meristem incorporation and finally fuse with the margins of the opposite carpel. These processes of meristem incorporation and fusion first lead to gamophylly and furthermore to carpel peltation, as is demonstrated by SEM-photographs (ring-shaped dike and common septum of the two carpels). As a result of carpel peltation, the lowest point of the septum deliminates the synascidiate zone. Above this point, the symplicate and, eventually, the plicate zone follows (vid. ventral suture). The margins of the carpel lamina merely touch each other without being coalesced. The preparation of a window in the carpel's dorsal side permits a look at a massive lateral placenta (Leinfellner 1951) developing the ovules. In the lower third—in lateral position at the placenta's margin—the first ovules are seen, the next ones follow in acropetal and basipetal direction, as well as to the periphery of the placenta.
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  • 98
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    Keywords: Angiosperms ; Limnanthaceae ; Limnanthes ; Biosystematics ; allozyme variation ; cluster analysis ; population divergence ; breeding system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sixty-one populations ofLimnanthes sect.Reflexae were surveyed for variation at 19 allozyme loci and reassessed for their morphological diversity and biosystematic relationships. Cluster analysis of allozyme data at individual population level provided evidence for a fairly good fit with the earlier systematic work on this genus but both morphological and allozyme data together defined some new clusters as well as exceptional entities. For example, only var.rosea of the fourL. douglasii varieties described byMason (1952) on the basis of geographical distribution, flower color and leaf morphology, remained as a distinct entity; the others were realigned along new geographic boundaries.L. striata appeared to have two well-developed subgroups, one of which was closely related to theL. douglasii complex. Further ecogeographic and hybridization studies are needed to fully describe these new phenetic findings in the context of phylogenetic inference. SectionInflexae was readily distinguished from sect.Reflexae by several diagnostic loci, thus supporting the validity of this division. Interspecific variation levels and population differentiation inLimnanthes were high when compared to other plant taxa, possibly indicating highly dynamic evolutionary processes for which variable habitats and extreme subdivision within species have been suggested as explanations.
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    Plant systematics and evolution 147 (1984), S. 189-203 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Ericaceae ; Onagraceae ; Mimosaceae ; Musaceae ; Ultrastructure ; function of pollen connecting threads and viscin threads ; palynology ; pollination ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Viscin threads and other pollen connecting threads of some angiosperm families were investigated, especially those ofEricaceae. According to the definition adopted, viscin threads are ± long exinous processes which consist of exinous material and connect pollen grains or tetrads. Such viscin threads are found within theOnagraceae, Caesalpiniaceae, Ericaceae, andMimosaceae only. While they differ in structure and composition, they always consist of sporopollenin and exhibit a very strong stickiness, even after all viscid substances have been removed by acetolysis. In contrast, the pollen connecting scleroprotein threads ofOrchidaceae and the cellular threads ofStrelitzia reginae Aiton. (Musaceae) are not connected with the exine surface, are destroyed by acetolysis, and thus do not correspond to viscin threads.
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    Plant systematics and evolution 147 (1984), S. 177-188 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Geraniaceae ; Pelargonium ; Chromosome numbers ; karyotypes ; microsporogenesis ; karyogeobotany ; karyotaxonomy ; karyotype evolution ; basic number
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The chromosome numbers of the 24 species of sect.Pelargonium were determined from field collected and cultivated plants of known localities in S. Africa. Twelve species are diploid (2n = 22), eight tetraploid (2n = 44), one hexaploid (2n = 66), and three octoploid (2n = 88). The chromosome numbers correlate well with the proposed subdivision of sect.Pelargonium. Its chromosomes are relatively small (1.0–1.5 µm) in comparison to most of the other sections, and its diploid karyotype is considered to be primitive. The occurrence of the basic number x = 11 in this section, in other sections of the genus, and in related genera (Monsonia, Sarcocaulon) leads to the conclusion that x = 11 probably is basic for the whole genus. — The pollen meiosis, microsporogenesis and pollen fertility of the diploid species is normal, with the exception of one, possibly young taxon from the Greyton Nature Reserve. The tetraploid species could be of autoploid origin, the higher polyploids exhibit a mixed auto-alloploid nature. — The 20 diploid and tetraploid species have a relatively small distribution range, most of them occur in the SW. Cape Province of South Africa. This area may therefore be considered as the centre of origin of the genus. Three of the four high polyploid species occupy rather large areas.
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