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.

The metabolism of phenanthrene was studied both in cell suspension cultures of wheat (Triticum aestivum) and soybean (Glycine max), and in intact plants of the water mossFontinalis antipyretica. Metabolism in cell suspension cultures strongly differed between the monocotyle and the dicotyle plant. Only small amounts oftrans-phenanthrene-9,10-dihydrodiole and phenanthrene-9,10-dione were detectable in the wheat culture. Soybean cultures, in contrast demonstrated a strong turnover resulting in a 75% reduction of the initial phenanthrene concentration. Metabolites were phenanthrene-9,10-dione, not further characterized polar metabolites and bound residues. Intact plants ofFontinalis antipyretica metabolized only small amounts of phenanthrene. Data obtained from cell cultures did not provide information for the metabolic potential in intact plants. Therefore standardized tests with model systems like suspension cultures lead to inadequate assessment of the ecological risk of certain xenobiotics.

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.

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.

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.

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.

This contribution deals with the relationship evaluated on the basis of 32 permanent monitoring plots. Tree volume increment as a total "brutto" and also as a pure "netto" change for 1 ha is defined. The first one includes also the influence of felling, mortality and increment ingrowth, second one includes only changes due to the growth process. Relationship of increment to stand variables is investigated bz stepwise regression. A more higher correlation to defoliation was found, less high to age, site index and altitude.