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  • 1
    Electronic Resource
    Electronic Resource
    Light-dependent net production of carbon monoxide by plants (1978)
    [s.l.] : Nature Publishing Group
    Nature 275 (1978), S. 740-741 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1 Dependence of CO ( ) and CO2 () exchange on irradiance. Leaf temperature 28.3C; CO concentration in the gas stream supplied to the gas-exchange chamber 2.07 mm3 m-3, average CO concentration within the chamber during the experiment 4.78 mm3 m-3; CO2 concentration 250 cm3m-3; O2 concentration ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/275740a0
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  • 2
    Electronic Resource
    Electronic Resource
    The effects of temperature and inhibitors of protein biosynthesis on the recovery from gas-shock of Acer pseudoplatanus cell cultures (1980)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 48 (1980), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The resumption of solute uptake capacity lost after gas-shock of Acer pseudoplatanus L. cell suspension cultures is severely inhibited by low temperatures (1°C) and by inhibitors of transcription and translation of protein synthesis such as 2-mercapto-1 (β-4-pyridethyl) benzimidazole (MPB, 40 μg ml−1), puromycin (around 100 μg ml−1) and actinomycin (100 μg ml−1). Cells that have already attained maximum uptake capacity loose it again after less than 1 h in 40 μg ml−1 MPB. Gel-electrophoresis of the external media of the cells shows that the release of proteins into the solution is affected by shock. The results demonstrate that proteins are involved in the mechanism of solute uptake by the cells, so that these proteins are among the factors altered during shock and recovery, and are important for the understanding of the after-effects of shock.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1980.tb03237.x
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of lithium and potassium on recovery of solute uptake capacity of Acer pseudoplatanus cells after gas-shock (1980)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 49 (1980), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: At concentrations of 10-−3M, Li+ inhibits the recovery of solute uptake capacity of Acer pseudoplatanus L. cell suspension cultures after gas-shock (i.e. after rapid exchange of the atmosphere in the culture flasks for ambient air). It also reduces solute uptake capacity of cells having already attained high rates of uptake during recovery from gas-shock. The effects of Li+ are much greater in cells which have been cultivated in 7 mM K+ solution than in cells cultivated with higher K+ levels (19 mM). Increasing K+ concentration during recovery reverses the effect of 10–3M Li+ and, with sufficiently high concentrations of K+ (≥ 10-−2M) during recovery, the solute uptake capacity of the fully recovered cells can even become greater than that of the control, at least for the low values of substrate concentration (here sulphate 10-−5M). Since Li+ does not affect the time course of solute uptake measured over 15–20 min, it is thought that it interacts with the synthesis and turnover of the solute uptake machinery of the Acer pseudoplatanus cells. Thermodynamic analysis of the flux data also supports the hypothesis that Li+ inhibits the biosynthesis of specific sites of solute permeation, but it does not rule out the possibility that K+ interferes rather on the forces acting on the transport of the considered solutes than on the catalytic structures of permeation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1980.tb08654.x
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  • 4
    Electronic Resource
    Electronic Resource
    Inhibition of the glucose and amino-acid carriers of Lemna gibba by pretreatment with HgCl2 (1983)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 57 (1983), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The electrical resting potential across the plasmalemma of Lemna gibba L. (G 1) cells is −230 to −250 mV and the diffusion potential in the presence of 1 mol m−3 KCN + 1 mol m−3 salicylhydroxamic acid is about −100 mV. A concentration of 0.01 mol m−3 HgCl2 depolarises the transmembrane electrical potential in a largely reversible way. When the cells after 16 min of HgCl2-application are returned to Hg-free solution, the transmembrane electrical potential is only depolarised by 24 × 13 mV (SD, n = 13) compared with the potential prior to HgCl2 treatment. In contrast, a 16 min pretreatment with HgCl2 followed by a wash with mercury-free solution reduces the transient depolarisations of transmembrane potential observed after addition of 5 mol m−3 D-glncose or 1 mol m−3 L-alaoine to about 60% of controls. These transient depolarisations are due to the onset of solute uptake. Accordingly, HgCl2-pretreatment inhibits uptake of 14C-3-O-methyl-d-glucose by more than 50% and uptake of 14C-l-alanine by more than 70%. Washing with 1 mol m−3 1,4-dithiothreitol does not reverse this inhibition. It is, therefore, concluded that Hg2+ irreversibly binds to essential SH-groups of the H+-hexose and the H+-amino-acid cotransport carriers of Lemna gibba and inhibits these carriers without appreciably affecting the electrogenic proton-extrusion pump.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1983.tb00730.x
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  • 5
    Electronic Resource
    Electronic Resource
    Solute Uptake of Acer pseudoplatanus Cell Suspensions during Recovery from Gas Shock (1979)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 46 (1979), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: When the ambient atmosphere of Acer pseudoplatanus cells in suspension culture is rapidly changed by opening the culture flasks and gently stirring (‘mild gas-shock’) or by filtering and suspending in new medium (‘strong gas-shock’), drastic modifications of the rates of leucine, methionine, glucose, adenine, sulphate and phosphate uptake are observed. Following the gas-shock, rates of uptake rapidly decrease within a few minutes. Subsequently the rates increase again to the intial level within several hours. The uptake of potassium, which is known to be passively distributed between the medium and the interior of many plant cells, at least at high external concentrations, is apparently independent of gas-shock.The shock and recovery kinetics are similar for all solutes investigated (except K+), in particular for different solutes studied in double labelling experiments with the same batch of cells. At the maximum of the after-effect of shock, i.e. at minimum rates of uptake, uptake shows a highly reduced dependence on temperatures. Gas-shock probably inactivates, denatures, structurally alters or releases membrane macromolecules engaged in transport. These molecules are then re-synthesized and re-incorporated into the membrane during recovery.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1979.tb02632.x
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  • 6
    Electronic Resource
    Electronic Resource
    Anion-sensitive ATPase activity and proton transport in isolated vacuoles of species of the CAM genus Kalanchoë (1984)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 62 (1984), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Vacuoles were isolated from leaves of Kalanchoë daigremontiana Hamet et Perrier de la Bathie, and the ionic sensitivity of the vacuolar ATPase was studied in vacuole homogenates desalted on Sephadex G-25. The ATPase activity was dependent on the presence of divalent cations (Mg2+≥ Mn2+≥ Ca2+, Co2+; Zn2+ had no effect). Mg2+-dependent ATPase activity was stimulated by anions (Cl− 〉 malate2+, HCO−3), with maximal stimulation at concentrations above 50 mM. Mg2+-Dependent activity was inhibited by NO−3 above 2 mM, but no saturation was observed up to 100 mM. No stimulation by K+ or Na+ was detected; stimulation by NH+4 was abolished by 0.01% (w/v) Triton X-100, suggesting that the NH+4 effect was due to the permeability of vacuolar membrane vesicles to NH3.Trans-tonoplast electrical potentials (Δψ) and intra-vacuolar pH were measured with glass microelectrodes and antimony covered glass micro-pH-electrodes, respectively. Free vacuofes isolated from Kalanchoë tubiflora (Harv.) Hamet were slightly positive with respect to the suspension medium. This Δψ was insensitive to the protonophore FCCP and depolarized by about 4 mV on addition of 50 mM KCl, still remaining about +5 mV. Upon addition of 7 mM Mg-ATP, vacuoles showed an FCCP-sensitive increase of Δψ from +9.2 ± 2.8 (13) to +17.8 ± 3.7 (12) mV [given as x̄± sd (n)] and an internal acidification from pH 5.4 ± 0.2 (11) to pH 4.3 ± 0.4 (12). Mg-ADP and ATP without Mg2+ had no effect on Δψ.It is concluded that the H4 pumping at the tonoplast is due to the functioning of the anion-sensitive vacuolar ATPase and that this is an essential part of the mechanism of nocturnal acid accumulation in CAM.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1984.tb04594.x
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  • 7
    Electronic Resource
    Electronic Resource
    The effect of light levels on daily patterns of chlorophyll fluorescence and organic acid accumulation in the tropical CAM treeClusia hilariana (1996)
    Springer
    Trees 10 (1996), S. 359-365 
    Details
    ISSN: 1432-2285
    Keywords: Chlorophylla fluorescence quenching ; Citric acid ; Malic acid ; Photochemistry ; Photosynthetic electron transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Sandy plains are characteristic of the coastal region of Brazil. We investigated the diel patterns of changes in organic acid levels, leaf conductance and chlorophylla fluorescence for sun-exposed and shaded plants ofClusia hilariana, one of the dominant woody species in the sandy coastal plains of northern Rio de Janeiro state. Both exposed and shaded plants showed a typical CAM pattern with considerable diel oscillations in organic acid levels. The degradation of both malic and citric acids during the midday stomatal closure period could lead to potential CO2 fixation rates of 28 μmol m-2 s-1 in exposed leaves. Moreover, exposed leaves exhibited large increases in total non-photochemical quenching (qN) accompanied by a substantial decrease in effective quantum yield during the course of the day. However, these potential high rates of CO2 fixation and the increases inqn of exposed plants were not enough to maintain the primary electron acceptor of photosystem II (qA) in a low reduction state, similar to that of shaded plants. As a result, there was a moderate increase in the reduction state of qA throughout the day. Most of the decline in photochemical efficiency of exposed leaves ofC. hilariana was reversible, as evidenced by the high levels of pre-dawn potential quantum yields (Fv/Fm) and their rapid recovery after sunset. However, the depletion of the organic acid pool in the afternoon resulted in an accentuated subsequent drop in Fv/Fm, suggesting that prolonged periods of water stress accompanied by high irradiance levels may expose plants ofC. hilariana in unprotected habitats to the danger of photoinhibition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02185639
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  • 8
    Electronic Resource
    Electronic Resource
    Supply and compartmentalization of potassium in mesophyll cells of the needles of spruce, Picea abies (L.) Karst. (1989)
    Springer
    Trees 3 (1989), S. 154-160 
    Details
    ISSN: 1432-2285
    Keywords: Picea abies (L.) Karst. ; Potassium ; Nutrition ; Compartmentalization ; Cell morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The water and potassium content and the relative vacuolar volume (α = Vvacuole/Vcell) of mesophyll cells of the needles of healthy 21-yearold spruce trees [Picea abies (L.) Karst.] were determined. In 5-year-old needles α was 0.626 ± 0.178 (ovx ± SD). Potassium concentrations in the bulk tissue water ranged from about 65 to 105 mM. Simulations were made using this information and a simple two-compartmental model of the cell with the bulk cytoplasm and the vacuole and assuming that the minimum cytoplasmic and vacuolar K+ concentrations are 100–150 mM and 10–15 mM respectively. It is shown that a K+ content of needles below 50 mmol/1 tissue water would be precarious for maintenance of normal physiological and metabolic performance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226651
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  • 9
    Electronic Resource
    Electronic Resource
    Attempts to measure plasmalemma and tonoplast electropotentials in small cells of the mossMnium using centrifugation techniques (1974)
    Springer
    The journal of membrane biology 18 (1974), S. 305-314 
    Details
    ISSN: 1432-1424
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Centrifugation techniques are described which allow that glass microelectrodes can be inserted separately into cytoplasm and vacuoles of intact cells of the mossMnium cuspidatum. This provides unequivocal measurements of the plasmalemma potential (E co between cytoplasm and outer medium). For various reasons, which are discussed in detail, determinations of the tonoplast potential (E vc between vacuole and cytoplasm) remain ambiguous. In the moss cells equilibrated with artificial pond water (APW),E co is highly negative (i.e. −130 to −190 mV).E vc is either close to 0 mV or positive (+60 to +65 mV) depending on the interpretation of the measurements. However, there is no reason to suggest that under these conditions highly negative potentials occur at the tonoplast.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01870119
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  • 10
    Electronic Resource
    Electronic Resource
    Electrochemical investigation of active malic acid transport at the tonoplast into the vacuoles of the CAM plantKalanchoë daigremontiana (1979)
    Springer
    The journal of membrane biology 47 (1979), S. 401-422 
    Details
    ISSN: 1432-1424
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The membrane potential of cells in leaf slices of the CAM plantKalanchoë daigremontiana Hamet et Perrier in the light and in the dark is −200 mV on the average; it is reversibly depolarized by the metabolic inhibitors FCCP (5×10−6 m) and CN− (5×10−3 m); it shows the light-dependent transient oscillations ubiquitously observed in green cells; it is independent of the amount of malic acid accumulated in the cells (in a tested range between 30 and 140mm); and it is considerably hyperpolarized by the fungal toxin fusicoccin (30×10−6 m). Fusicoccin inhibits nocturnal malic acid accumulation in intact isolated phyllodia of the CAM plantKalanchoë tubiflora (Harv.) Hamet but does not affect remobilization of malic acid during the day. Electrochemical gradients for the various ions resulting from dissociation of malic acid, i.e., H+, Hmal− and mal2−, were calculated using the Nernst equation. With a very wide range of assumptions on cytoplasmic pH and malate concentration results of calculations suggest uphill transport of H+ and Hmal− from the cytoplasm into the vacuole, while mal2− might be passively distributed at the tonoplast. On the basis of the present data the most likely mechanism of active malic acid accumulation in the vacuoles of CAM plants appears to be an active H+ transport at the tonoplast coupled with passive movement of mal2− possibly mediated by a translocator (“catalyzed diffusion”), with subsequent formation of Hmal− (2 H++mal2−→H++Hmal−) at vacuolar pH's.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01869746
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