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  • 1
    Electronic Resource
    Electronic Resource
    In vivo temperature response functions of parameters required to model RuBP-limited photosynthesis (2003)
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 26 (2003), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The leaf model of C3 photosynthesis of Farquhar, von Caemmerer & Berry (Planta 149, 78–90, 1980) provides the basis for scaling carbon exchange from leaf to canopy and Earth-System models, and is widely used to project biosphere responses to global change. This scaling requires using the leaf model over a wider temperature range than that for which the model was originally parameterized. The leaf model assumes that photosynthetic CO2 uptake within a leaf is either limited by the rate of ribulose-1,5-bisphosphate (RuBP) regeneration or the activity of RuBP carboxylase-oxygenase (Rubisco). Previously we reported a re-parameterization of the temperature responses of Rubisco activity that proved robust when applied to a range of species. Herein this is extended to re-parameterizing the response of RuBP-limited photosynthesis to temperature. RuBP-limited photosynthesis is assumed to depend on the whole chain electron transport rate, which is described as a three-parameter non-rectangular hyperbolic function of photon flux. Herein these three parameters are determined from simultaneous measurement of chlorophyll fluorescence and CO2 exchange of tobacco leaves, at temperatures from 10 to 40 °C. All varied significantly with temperature and were modified further with variation in growth temperature from 15 to 35 °C. These parameters closely predicted the response of RuBP-limited photosynthesis to temperature measured in both lemon and poplar and showed a significant improvement over predictions based on earlier parameterizations. We provide the necessary equations for use of the model of Farquhar et al. (1980) with our newly derived temperature functions for predicting both Rubisco- and RuBP-limited photosynthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.0016-8025.2003.01050.x
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  • 2
    Electronic Resource
    Electronic Resource
    Improved temperature response functions for models of Rubisco-limited photosynthesis (2001)
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 24 (2001), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Predicting the environmental responses of leaf photosynthesis is central to many models of changes in the future global carbon cycle and terrestrial biosphere. The steady-state biochemical model of C3 photosynthesis of Farquhar et al. (Planta 149, 78–90, 1980) provides a basis for these larger scale predictions; but a weakness in the application of the model as currently parameterized is the inability to accurately predict carbon assimilation at the range of temperatures over which significant photosynthesis occurs in the natural environment. The temperature functions used in this model have been based on in vitro measurements made over a limited temperature range and require several assumptions of in vivo conditions. Since photosynthetic rates are often Rubisco-limited (ribulose, 1-5 bisphosphate carboxylase/oxygenase) under natural steady-state conditions, inaccuracies in the functions predicting Rubisco kinetic properties at different temperatures may cause significant error. In this study, transgenic tobacco containing only 10% normal levels of Rubisco were used to measure Rubisco-limited photosynthesis over a large range of CO2 concentrations. From the responses of the rate of CO2 assimilation at a wide range of temperatures, and CO2 and O2 concentrations, the temperature functions of Rubisco kinetic properties were estimated in vivo. These differed substantially from previously published functions. These new functions were then used to predict photosynthesis in lemon and found to faithfully mimic the observed pattern of temperature response. There was also a close correspondence with published C3 photosynthesis temperature responses. The results represent an improved ability to model leaf photosynthesis over a wide range of temperatures (10–40 °C) necessary for predicting carbon uptake by terrestrial C3 systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.2001.00668.x
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  • 3
    Electronic Resource
    Electronic Resource
    Intrinsic water use efficiency at the pollination stage as a parameter for drought tolerance selection in Phaseolus vulgaris (1999)
    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 106 (1999), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Genotype differences in gas exchange during ontogeny and water stress responses at the vegetative and pollination stages were evaluated in four lines of Phaseolus vulgaris L. In the cultivar Carioca, net photosynthetic rate (A) and stomatal conductance (gs) were lower at the vegetative stage (20 days after sowing [DAS]) and maximum at the pollination stage (39 DAS), followed by a decrease at the flowering stage (46 DAS) and a dramatic fall at the grain-filling stage (60 DAS). Among the lines studied, the stomata of A320 closed faster than those of the other lines when water stress occurred at 20 or 39 DAS. The cultivar SC-90298823 had greater stomatal conductance at 39 DAS and a higher photosynthetic level than the other lines. Stomata of Ouro negro remained partially open during the water stress at the pollination stage (39 DAS) and supported a positive net photosynthetic rate (A). Differences were also found between lines in intrinsic water use efficiency (IWUE) at 39 DAS, but not at 20 DAS. The possibility of using IWUE at the pollination stage is discussed, in view of its use as one of the parameters for a drought tolerance breeding program in bean lines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1399-3054.1999.106206.x
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  • 4
    Electronic Resource
    Electronic Resource
    Precision interplanar spacing measurements of boron-doped silicon (1983)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 16 (1983), S. 486-492 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: A study of the lattice parameters of boron-doped silicon (1014−1019 cm−3) grown in (111) and (001) directions by the Czochralski technique has been undertaken. Interplanar spacings (d) were measured by the pseudo-Kossel technique to a precision of 0.001%; different procedures to obtain d and the errors are discussed. The crystallographic planes are found to contract preferentially and the usual study of parameter variation must be made as a function of d. The diffused B particularly contracts the {333} plane, which is more pronounced in high concentrations. An orientation dependence of the diffusion during growth was observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889883010870
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  • 5
    Electronic Resource
    Electronic Resource
    X-ray diffraction profiles fron neutron-irradiated LiF single crystals (1977)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 10 (1977), S. 390-396 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The detailed measurement of the Bragg line profiles of several X-ray reflections from six single-crystal samples of LiF irradiated under different and well defined conditions in the core of a swimming-pool type nuclear reactor are reported. The crystals were irradiated with three different spectra: (a) total neutron spectrum plus the γ background radiation, (b) same as (a) without thermal neutrons, the crystal being wrapped in a cadmium foil, and (c) the background γ radiation alone. The experimental results presented display the changes in the profiles due to the different radiation spectra used and to the change in irradiation temperature within the interval from 113 to about 173°C. That peak intensities decrease while integrated intensities increase with irradiation is a well known result amply confirmed here. Integrated intensities in these experiments increase from 4 to 14 times with respect to the unirradiated crystal. The strongest reflections (111, 200 and 220) experienced the highest increases. The influence of the temperature of irradiation has been verified through measurements of reflections 111, 200 and 220 from crystals irradiated at temperatures of 113, 148 and 173°C. As the irradiation temperature rises the peak intensities clearly tend to those of the unirradiated crystal while integrated intensities attain a maximum at about 150°C. The results also indicate that at least under the conditions prevailing in the present experiments the highest amount of damage is due to thermal neutrons (E ≤ 0.45 eV).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S002188987701382X
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  • 6
    Electronic Resource
    Electronic Resource
    Considerations about reactions occurring in pile irradiation of LiF crystals
    Amsterdam : Elsevier
    Nuclear Instruments and Methods 148 (1978), S. 199-202 
    Details
    ISSN: 0029-554X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0029-554X(78)90354-3
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