Fraunhofer-Institut für Atmosphärische Umweltforschung IFU

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  • Publication
    Black alder (Alnus Glutinosa (L.) Gaertn.) trees mediate methane and nitrous oxide emission from the soil to the atmosphere
    ( 1998)
    Rusch, H.
    ;
    Rennenberg, H.
    Three-year-old seedlings of black alder (Alnus glutinosa (L) Gaertn.), a common European wetland tree species, were grown in native soil taken from an alder swamp. Fluxes of methane (CH4) and nitrous oxide (N2O) between the tree stem and the atmosphere were determined under controlled conditions. Both CH4 and N2O were emitted through the bark of the stem into the atmosphere when the root zone exhibited 'higher-than-ambient' CH4 and N2O gas mixing ratios. Flooding of the soil caused a decreased N2O emission but an increased CH4 efflux from the stem. Immediately after flooding of the soil, N2O was emitted from the seedlings' bark at a rate of 350 my mol N2O m(-2) h(-1) whereas CH4 flux could not be detected. After more than 40 days of flooding CH4 fluxes up to 3750 my mol CH4 m(-2) h(-1) from the stem were measured, while N2O emission had decreased below the limit of detection. Gas efflux decreased with increasing stem height and correlated with gas mixing ratios in the soil, indicating diffusion through the aerenchyma as the major path of gas transport. From these results it is assumed that woody species with aerenchyma can serve as conduits for soil-derived trace gases into the atmosphere, to date only shown for herbaceous plants. This, yet unidentified, 'woody plant pathway' contributes to the total greenhouse gas source strength of wetlands.
  • Publication
    Exchange of NO and NO2 between wheat canopy monoliths and the atmosphere
    ( 1996)
    Weber, P.
    ;
    Rennenberg, H.
    The fluxes of NO and NO2 between wheat canopy monoliths and the atmosphere were investigated with the dynamic chamber technique. For this purpose monoliths were dug out at different plant growth stages from a field site, transported to the institute, and placed in an environmental growth chamber. The wheat canopy monoliths were exposed over a period of four days to the average ratios of atmospheric NO2 and NO measured at the field site, i.e. NO2 concentration of about 18 mL L(-1) plus NO concentration lower than 0.5 nL L(-1). Under these conditions NO emission into the atmosphere and NO2 deposition into canopy monoliths was observed. Both fluxes showed diurnal variation with maximum rates during the light and minimum rates during darkness. NO2 fluxes correlated with soil temperature as well as with light intensity. NO fluxes correlated with soil temperature but not with light intensity. From the investigation performed the diurnal variation of the NO and NO2 compensation points, the ma ximum rates of NO and NO2 emission, and the total resistances of NO and NO2 fluxes were calculated. Under the assumption that the measured data are representative for the whole vegetation period, annual fluxes of NO and NO2 were estimated. Annual NO emission into the atmosphere amounted to 87 mg N m(-2) y(-1) (0.87 kg ha(-1) y(-1), annual NO2 deposition into canopy monoliths amounted to 1273 mg N m- 2 y(-1) (12.73 kg ha(-1) y(- 1). Apparently, the uptake of atmospheric nitrogen by the wheat field from NO2 deposition is about 15 times higher than the loss of nitrogen from NO emission. It can therefore be assumed that even in rural areas wheat fields are a considerable sink for atmospheric nitrogen. The annual sink strength estimated in the present study is ca. 12 kg N ha(-1) y(-1). The possible origin of the NO emitted and the fate of atmospheric NO2 taken up by the wheat canopy monoliths are discussed.
  • Publication
    The antioxidative system in manganese-deficient spruce needles (Picea abies, L.)
    ( 1992)
    Polle, A.
    ;
    Chakrabarti, K.
    ;
    Chakrabarti, S.
    ;
    Seifert, G.
    ;
    Schrammel, P.
    ;
    Rennenberg, H.
  • Publication
    Reduced glutathione (GSH) transport into cultured tobacco cells
    ( 1992)
    Schneider, A.
    ;
    Martini, N.
    ;
    Rennenberg, H.
  • Publication
    Emission of volatile sulfur compounds from spruce trees.
    ( 1990)
    Huber, B.
    ;
    Stahl, K.
    ;
    Haunold, W.
    ;
    Georgii, H.-W.
    ;
    Slovik, S.
    ;
    Pfanz, H.
    ;
    Rennenberg, H.
    ;
    Schröder, P.
    Spruce (Picea abies L.) trees from the same clone were supplied with different amounts of plant available sulfate in the soil (9.7-18.1 milligrams per 100 grams of soil). Branches attached to the trees were enclosed in a dynamic gas exchange cuvette and analyzed for the emission of volatile sulfur compounds. Independent of the sulfur supply in the soil, H2S was the predominant reduced sulfur compound continuously emitted from the branches with high rates during the day and low rates in the night. In the light, as well as in the dark, the rates of H2S emission increased exponentially with increasing water vapour flux from the needles. Approximately 1 nanomole of H2S was found to be emitted per mole of water. When stomata were closed completely, only minute emission of H2S was observed. Apparently, H2S emission from the needles is highly dependent on stomatal aperture, and permeation through the cuticle is negligible. In several experiments, small amounts of dimethylsulfide and carbonyls ulfide were also detected in a portion of the samples. However, SO2 was the only sulfur compound consistently emitted from branches of spruce treess in addition to H2S. Emission of SO2 mainly proceeded via an outburst starting before the beginning of the light period. The total amount of SO2 emitted from the needles during this outburst was correlated with the plant available sulfate in the soil. The diurnal changes in sulfur metabolism that may result in an outburst of SO2 are discussed.
  • Publication
    Superoxide dismutase activity in needles of Norwegian spruce tress. Picea abies L.
    ( 1989)
    Krings, B.
    ;
    Polle, A.
    ;
    Rennenberg, H.
    The activity of superoxide dismutase was investigated in needles of spruce trees. To obtain maximum activity, needles were homogenized in the presence of Triton X-100 and polyvinylpyrrolidone. Superoxide dismutase activity was measured in dialyzed extracts with a modified epinephrine assay (HP Misra, I Fridovich (1972) J Biol Chem 247: 3170-3175) at pH 10.2. The extracts contained 70 to 120 units of superoxide dismutase per milligram protein. On unit of superoxide dismutase was completely inhibited in the presence of 20 micromolar NaCN. On native polyacrylamide gels three electromorphs were visualized after staining for activity. All three species were sensitive to CN high minus and H2O2 and were therefore assumed to be Cu/Zn-superoxide dismutases. Superoxide dismutase activity was dependent on the age of the needles and declined by approximately 25% within 3 to 4 years.
  • Publication
    Recovery of sulfate transport into heterotrophic tobacco cells from inhibition by reduced glutathione.
    ( 1989)
    Kemper, O.
    ;
    Rennenberg, H.
    ;
    Thoene, B.
    In heterotrophic tobacco cells (Nicotiana tabacum L. cv. Samsun) inhibition of sulfate transport by reduced glutathione (GSH) is a reversible process. When GSH was removed from the culture medium subsequent to a 10-h treatment with 1 mM GSH, sulfate transport began to recover after a lag period of ca 4 h and reached the transport rates of controls without GSH within another 3-4 h. Recovery was prevented when inhibitors of protein synthesis, i.e. cycloheximide or puromycin, were added to the medium upon removal of GSH, even if low concentrations (cycloheximide 1 myM; puromycin 250 myM) were applied. At these low concentrations the rate of synthesis of sulfate transport entities was maintained at the rate of degradation in the absence of GSH. The post-transcriptional polyadenylation inhibitor cordycepin and the transcription inhibitor alpha-amanitin only slightly reduced recovery of sulfate transport from inhibition by GSH. Apparently, protein synthesis is required for this recovery, sug gesting that inhibition of synthesis of sulfate carrier entities is the mechanism of action of GSH on sulfate transport in heterotrophic tobacco cells. An initial rate of net increase in sulfate transport during recovery from inhibition of GSH of 3.6 plus minus 0.2 U h minus 1 was calculated (1 U = 1 nmol sulfate (g DW) minus high 1 min high minus 1). This rate of increase is small compared with the rate of decrease in sulfate transport at maximum inhibition by cycloheximide (110 plus minus 3 U h high minus minus 1). However, with increasing time of exposure without GSH.
  • Publication
    Gamma-Glutamylcyclotransferase in tobacco suspension cultures - Catalytic properties and subcellular localization
    ( 1987)
    Rennenberg, H.
    ;
    Schweihofen, B.
    ;
    Steinkamp, R.
    Gamma-Glutamylcyclotransferase activity (EC 2.3.2.4) in ammonium sulfate precipitates (40-70% saturation) of extracts from cultured tobacco cells (Nicotiana tabacum L.cv.Samsun) was analyzed as liberation of 5-oxo-proline from L-gamma-glutamyl dipeptides. The enzyme was highly specific for the sulfur containing gamma-glutamyl dipeptides gamma glutamyl-L-methionine and gamma-glutamyl-L-cysteine. Maximum activity was obtained at pH 8.7 and 35 degrees C. As also observed with animal gamma-glutamylcyclotransferase, the tobacco enzyme exhibited a relatively low substrate affinity (gamma-glutamyl-L-methionine: K sub m 2.2 +- 0.4 mM). In contrast to animal gamma-glutamylcyclotransferase, the tobacco enzyme was not inhibited by the D-isomer of the substrate D-gamma-Glutamyl-L-methionine; it also did not use the D isomer as a substrate. Gamma-Glutamylcyclotransferase of tobacco cells was shown to be a soluble enzyme entirely localized in the cytoplasm. (IFU)
  • Publication
    Growth and hydrogen sulfide emission of photoheterotrophic tobacco cells supplied with l-cysteine as sole sulfur source
    ( 1985)
    Grundel, I.
    ;
    Rennenberg, H.
    Growth of photoheterotrophic tobacco cells (Nicotiana tabacum L. var."Samsun") in suspension cultures is inhibited in the presence of 0.8 mM L-cysteine as sole sulfur source, when inoculated at densities up to 9.5 mg dry weight. Under these conditions, hydrogen sulfide is emitted in amounts increasing with increasing inoculation densities. An inoculum of 19 mg dry weight, however, enables a moderate growth of the cells (doubling time 178 h) while reducing the emission of hydrogen sulfide. Feeding of 0.4 mM L-leucine to the suspension did not only reduce hydrogen sulfide emission at all inoculation densities applied; it also caused exponential growth (doubling time 110 h) at inoculation densities of 9.5 mg and upwards. Initial and final rate of growth of tobacco cells supplied with L-cysteine as sulfur source increased, hydrogen sulfide emission decreased with increasing L-leucine concentrations in the medium. These effects are not specific for L-leucine, but are also observed when L-is oleucine, L-threonine, or L-valine were added to the suspensions. Support of growth and suppression of hydrogen sulfide emission by L-leucine is accompanied by a reduction of the initial as well as the final rate of uptake of L-cysteine by the cells. (IFU)