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The effects of acid precipitation and ozone on the ectomycorrhizae of red spruce saplings
1998
Roth, D.R. (Cornell Univ., Ithaca, NY (USA). Dept. of Natural Resources) | Fahey, T.J.
Phosphine by bio-corrosion of phosphide-rich iron Texte intégral
1998
Glindemann, Dietmar | Eismann, Frank | Bergmann, Armin | Kuschk, Peter | Stottmeister, Ulrich
Phosphine is a toxic agent and part of the phosphorus cycle. A hitherto unknown formation mechanism for phosphine in the environment was investigated. When iron samples containing iron phosphide were incubated in corrosive aquatic media affected by microbial metabolites, phosphine was liberated and measured by gas chromatography. Iron liberates phosphine especially in anoxic aquatic media under the influence of sulfide and an acidic pH. A phosphine-forming mechanism is suggested: Phosphate, an impurity of iron containing minerals, is reduced abioticly to iron phosphide. When iron is exposed to the environment (e.g. as outdoor equipment, scrap, contamination in iron milled food or as iron meteorites) and corrodes, the iron phosphide present in the iron is suspended in the medium and can hydrolyze to phosphine. Phosphine can accumulate to measurable quantities in anoxic microbial media, accelerating corrosion and preserving the phosphine formed from oxidation.
Afficher plus [+] Moins [-]Pollution prevention in Colorado commercial greenhouses
1998
Panter, Karen L. | Newman, Steven Earl | Waskom, R. M (Reagan McTier)
Norway spruce fine roots investigation in the West Beskids Mts.
1998
Kodrik, M. (Slovenska Akademia Vied, Zvolen (Slovak Republic). Ustav Ekologie Lesa)
Allometric relationships between stem volume and the biomass of Norway spruce
1998
Pokorny, R. (Akademie Ved, Brno (Czech Republic). Ustav Ekologie Krajiny)
The objectives of this study were (I) to establish allometric relationships between the stem volume and biomass of the stem, branches, leaves and the leaf area, and crown dimensions of individual trees, (II) to determine the relative aboveground biomass distribution, (III) to determine the vertical gradient of the specific leaf area and (IV) to estimate the aboveground stand biomass and the leaf area. Diameter at 0.3m height above ground and height of each tree were measured as the basic biometrical characteristics. The coefficient of the shape of the trunk was found by Huber's method.
Afficher plus [+] Moins [-]Long-term influence of enhanced UV-B irradiation on photosynthetic characteristic of Norway spruce (Picea abies) in the conditions of the Beskids Mts. [Czech Republic]
1998
Sprtova, M. | Marek, M.V. (Akademie Ved, Brno (Czech Republic). Ustav Ekologie Krajiny)
The cloned saplings of Norway spruce (7 years old) were exposed to ambient UV-B irradiation or enhanced BV-B irradiation (+25 %) continuously over three growing seasons. Comprehensive analysis of CO2 assimilation and chlorophyll a fluorescence was performed at the end of the third growing season to evaluate the influence of enhanced UV-B irradiation. The analysis resulted in observations of decreased photosynthetic activity, mainly of RUBISCO activity, as a result of long-term influence of enhanced UV-B irradiation. Morever, the deep impact of enhanced UV-B irradiance on the level of electron transport and thus enhanced sensitivity to photo-inhibition was demonstrated.
Afficher plus [+] Moins [-]A study of the effect of the growth activity of grasses on accumulation and losses of organic matter and nutrients on deforested sites [Czech Republic]
1998
Fiala, K. | Tuma, I. | Holub, P. (Akademie Ved, Brno (Czech Republic). Ustav Ekologie Krajiny)
Analysis of control factors of the development of forest ecosystems at the higher altitudes of the Moravian-Silesian Beskids Mts. [Czech Republic]
1998
Kulhavy, J. | Klimo, E. | Hadas, P. (Mendelova Zemedelska a Lesnicka Univ., Brno (Czech Republic))
Possibilities of using ground basic rock flours in forestry
1998
Vavricek, D. (Mendelova Zemedelska a Lesnicka Univ., Brno (Czech Republic))
Surface liming even in higher doses did not affected soil Ph and improving the content of Mg and Ca was only temporary. Spot fertilization by fine-ground amphibolite is significant particularly from the aspect of long-term affects. Short-term affects manifested themselves slightly but in the whole system of particular parameters. Application of higher amounts (3 kg.ha-1) of amphibolite has its substantiation in the future.
Afficher plus [+] Moins [-]Physiological aspects of the health state of Norway spruce using different silvicultural concepts
1998
Kmet, J. | Jaloviar, P. (Technicka Univ., Zvolen (Slovak Republic). Lesnicka Fakulta)
The sample trees from two stands managed by different management systems - shelterwood and selection systems, and two generations within each stand, were compared. The evaluation of the potential acidity and conductivity of dry-mass extracts (KSE) proved an adverse effect of environment on the maternal stand in the shelterwood forest. The KSE-values are systematically higher in samples taken from the young as well as mature sample trees in the selection forest. Despite the limited duration and extent of the investigations, a better ecological stability of the selection forest as compared with the shelterwood one was observed.
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