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Sökning: LAR1:gu > (2004) > Pleijel Håkan 1958 > Karlsson Per Erik 1957

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  • Karlsson, Per Erik, 1957-, et al. (författare)
  • A cumulative ozone uptake-response relationship for the growth of Norway spruce saplings
  • 2004
  • Ingår i: Environmental Pollution. - 0269-7491. ; 128:3, s. 405-417
  • Tidskriftsartikel (refereegranskat)abstract
    • Norway spruce saplings [Picea abies (L.) Karst.] were exposed during four growing seasons to different ozone treatments in open-top chambers: charcoal filtered air (CF), non-filtered air (NF) and non-filtered air with extra ozone (NF+, 1.4xambient concentrations). The CF and NF + ozone treatments were combined with phosphorous deficiency and drought stress treatments. The total biomass of the trees was harvested at different intervals during the experimental period. The ozone uptake to current-year needles of the Norway spruce saplings was estimated using a multiplicative stomatal conductance simulation model. There was a highly significant correlation between the reduction of total biomass and the estimated cumulative ozone uptake, which did not vary when different thresholds were applied for the rate of ozone uptake. The reduction of the total biomass was estimated to 1 per 10 mmol m(-2) cumulated ozone uptake, on a projected needle area basis. (C) 2003 Elsevier Ltd. All rights reserved.
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  • Karlsson, Per Erik, 1957-, et al. (författare)
  • Marknära ozon, SO2, NO2 och sot vid Östads Säteri 1987-2003
  • 2004
  • Rapport (övrigt vetenskapligt)abstract
    • IVL Svenska Miljöinstiutet AB har tillsammans med Göteborgs Universitet bedrivit experimentell forskning kring inverkan av luftföroreningar på växtligheten vid Östads säteri sedan 1987. Östads säteri är beläget i Alingsås kommun vid sjön Mjörn, ca 45 km nordost om Göteborg. Den experimentella verksamheten har främst varit inriktad på inverkan av marknära ozon på skördeavkastning hos vete samt inverkan på tillväxten hos gran och björk. I samband med experimenten har mätningar gjorts av halterna i omgivningsluften av olika gasformiga luftföroreningar, främst ozon, NO2 och SO2, samt sot. I föreliggande rapport har dessa mätningar sammanställts och olika medlevärden samt ackumulerade ozonexponerings index beräknats. Dessa har jämförts med motsvarande medelvärden och ackumulerade index från relevanta omkringliggande mätlokaler i södra Sverige.
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  • Pleijel, Håkan, 1958-, et al. (författare)
  • Relationships between ozone exposure and yield loss in European wheat and potato - a comparison of concentration- and flux-based exposure indices
  • 2004
  • Ingår i: Atmospheric Environment. - 1352-2310. ; 38:15, s. 2259-2269
  • Tidskriftsartikel (refereegranskat)abstract
    • Data from open-top chamber experiments with field grown crops, performed in Sweden, Finland, Belgium, Italy and Germany, were combined to derive relationships between yield and ozone exposure for wheat (Triticum aestivum L.) and potato (Solanum tuberosum L.). Three different exposure indices were compared: AOT40 (accumulated exposure over a threshold ozone concentration of 40 nmol mol(-1)), CUOt (cumulative stomatal uptake of ozone, using a constant ozone uptake rate threshold of t nmol m(-2) s(-1)) and mAOTc(0) (conductance modified AOT using a threshold concentration for ozone of c(0) nmol mol(-1)). The latter is essentially a combination of AOT and CUO. Ozone uptake was estimated using a Jarvis-type multiplicative model for stomatal conductance. In terms of correlation between relative yield (RY) and ozone exposure, CUO5, the CUO index with an ozone uptake rate threshold of 5 nmol m(-2) s(-1), performed best for both wheat and potato, resulting in r(2) values of 0.77 and 0.64, respectively. CUO5 performed considerably better in terms of the correlation between RY and ozone exposure, than AOT40 for wheat, while mAOT10, the best performing mAOT index in this case, was intermediate in performance for this crop. For potato, the differences between the different ozone exposure indices AOT40, CUO5 and mAOT20 (the mAOT index performing best for potato) in the correlation between RY and ozone exposure were relatively small. To test the assumption that the non-stomatal deposition of ozone was negligible for the uppermost, sunlit leaves, measurements of ozone uptake in relation to leaf conductance for water vapor of wheat leaves in a cuvette system were used. The non-stomatal deposition of ozone to the leaves turned out to be comparatively small. Based on the non-stomatal conductance (g(ns) = 15 mmol m(-2) s(-1)) estimated for the wheat leaves in the cuvette system, it was concluded that the consequence of omitting the non-stomatal conductance is small. In conclusion the study indicated that the ozone uptake based approach showed a high degree of fitting along a north-south European transect of pedoclimatic conditions, and represents a better and more relevant approach to the quantification of ozone effects on crops growth than the use of ozone exposure indices purely based on ozone concentrations. (C) 2004 Elsevier Ltd. All rights reserved.
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  • Skarby, L., et al. (författare)
  • Growth of Norway spruce (Picea abies) in relation to different ozone exposure indices: a synthesis
  • 2004
  • Ingår i: Atmospheric Environment. - 1352-2310. ; 38:15, s. 2225-2236
  • Tidskriftsartikel (refereegranskat)abstract
    • In the Goteborg Ozone-Spruce Project (GOSP), two independent open-top chamber experiments were conducted during four growing seasons, using one clone of Norway spruce (Picea abies). The experiments tested the impact of ozone, alone and in combination with low phosphorus supply and in combination with drought stress, respectively, on biomass accumulation. In this paper, the results from both experiments were combined for the first time in order to analyse the relationship between relative biomass accumulation and different exposure indices (accumulated exposure over a threshold (AOT) with different cut-off concentrations, and the sum of ozone concentrations above 60 nl l(-1), referred to as SUM06). In addition, a pooled analysis was made on several European studies of Norway spruce as a first effort to synthesize independent data and test the relative growth in relation to the AOT40 index. Significant negative relationships between the relative biomass of the GOSP-clone and the different indices were obtained. AOT20 and AOT30 resulted in the highest correlations. Based on the regression model, ozone is predicted to reduce the biomass of the GOSP-clone by 1% at the critical level for forest trees in Europe, a seasonal AOT40 of 10 mul l(-1) h. A significant negative relationship between relative growth and AOT40 was obtained also with the European data set. At the present ozone critical level, the model predicted a 6% reduction in growth for the most sensitive Norway spruce trees in this data set. (C) 2004 Elsevier Ltd. All rights reserved.
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  • Uddling, Johan, 1972-, et al. (författare)
  • Biomass reduction of juvenile birch is more strongly related to stomatal uptake of ozone than to indices based on external exposure
  • 2004
  • Ingår i: Atmospheric Environment. - 1352-2310. ; 38:28, s. 4709-4719
  • Tidskriftsartikel (refereegranskat)abstract
    • In order to test the hypothesis that ozone-induced limitation of biomass production in juvenile silver birch (Betula pendula Roth) is driven by stomatal uptake of ozone (O-3) rather than external exposure, biomass reduction was related to the cumulative uptake of O-3 through stomata over an uptake cut-off threshold of x nmol O-3 m(-2) s(-1) (CUO > x), to the accumulated exposure to O-3 over a threshold of y nmol mol(-1) during daylight hours (daylight AOTy) or during 24 h (24 h AOTy), and to the sum of daytime concentrations exceeding 60 nmol mol(-1) (SUM06). The analysis included data from nine different experiments conducted in Sweden, Finland and Switzerland. Stomatal uptake of O-3 was estimated using a stomatal conductance (g,) model including g, response functions for photosynthetic photon flux density, water vapour pressure deficit of the air and air temperature. Experiment-specific maximum g(s) (g(max)) as well as g(s) in darkness (g(dark)) were assessed through local measurements. Biomass reduction Was more strongly related to CUO > x than to SUM06 and daylight or 24 h AOTy, but the difference between CUO > x and 24 h AOTy was small. The better performance of CUO > x was dependent on the use of site- and experiment-specific g(max) and g(dark) values, and there was a positive relationship between g(max) and biomass reduction per unit AOT40. Daylight AOTy and SUM06 could not account for the growth limiting impact of nocturnal O-3 uptake in the Swiss experiments. A sensitivity analysis revealed that the CUO > x estimates were largely insensitive to the estimate of the conductance for non-stomatal leaf surface deposition of O-3, as a result of turbulent conditions at the experimental plots. In summary, we conclude that CUO > x was more successful in accounting for the variation in biomass reduction in juvenile birch as compared to indices based on external exposure, if g(max) and g(dark) were locally parameterised. (C) 2004 Elsevier Ltd. All rights reserved.
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  • Uddling, Johan, 1972-, et al. (författare)
  • Measuring and modelling leaf diffusive conductance in juvenile silver birch, Betula pendula
  • 2004
  • Ingår i: Trees-Structure and Function. - 0931-1890. ; 18:6, s. 686-695
  • Tidskriftsartikel (refereegranskat)abstract
    • Leaf diffusive conductance for water (g(l)) and twig xylem pressure (psi(xt)) was measured in juvenile silver birch, Betula pendula, under field conditions in southern Sweden. Data from one site were used to parameterise two different multiplicative models for g(l) (dependent data), and measurements from another site were used to validate these models (independent data). In addition, experiments were performed in controlled environments to validate the g(l) response functions used in the models. The driving variables in the D-model were photosynthetic photon flux density, air temperature and water vapour pressure deficit of the air (D-a), while the DH-model also included the accumulated hours after sunrise each day with D-a above a certain threshold (H). Both models satisfactorily predicted the variation in g(l) in dependent as well as in independent data, and the g(l) response functions used were supported by the experiments in controlled environments. The DH-model was more successful in predicting g(l) than the D-model by accounting for the observation that g(l) was lower at higher H under similar weather conditions. There was a considerable variation in maximum g(l) during the season, as well as between the two sites. On relatively warm and dry days psi(xt) rapidly declined during the morning and then stabilized around a constant value until the late afternoon, with the stomatal regulation effectively preventing psi(xt) from decreasing below this value. We suggest that these models could be used to simulate the g(l) in juvenile birch if maximum g(l) is locally estimated and if the response functions are not extrapolated beyond the climate range for this study.
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