Cytogenetical and biochemical investigations of common oak (Quercus robur L.) were applied in order to find suitable markers in bioindication of oak populations. In cytogenetical analyses the chromosome aberration and mitotic index were recorded. Chromosome banding, B-chromosomes, location and number of nuclear organizer regions were indicated using Giemsa C-banding method, fluorescence staining and silver impregnation. In biochemical analyses SDS-electrophoresis of soluble proteins and isoelectric focusing of isoperoxidases were used.

It was our aim to investigate whether the cytokinin status of Norway spruce seedlings (Picea abies L. Karst.) was changed when the plants were grown under nutritive stress. Cytokinins in shoots and roots from spruce seedlings, grown in various hydrocultural media with complete (control) or poor nutrient supply (stress), were determined by an indirect competitive enzyme-liked immunosorbent assay. The shoots of spruce seedlings grown in a poor acidic culture medium, to which aluminium ions (AlCl3, 0.8 mM) were added, showed up to 5-fold higher concentrations of zeatin riboside and isopentenyladenosine (iPa). When adding naphtylacetic acid to the nutrient medium also higher levels of cytokinin ribosides were measured in the shoots. In the roots however cytokinin riboside levels did not increase significantly under Al- or auxin treatment. Feeding experiments using tritiated iPA have shown that the metabolism of this cytokinin is strongly retarded in the roots of stressed seedlings. The experiments show that acid conditions and nutrient shortage together with aluminium ions in the rhizosphere increase the number of lateral roots in Norway spruce seedlings. It is assumed that the increased number of sites of cytokinin biosynthesis and the reduced metabolism of iPA result in the higher content of cytokinin ribosides in the shoots of seedlings.

With the development of molecular marker technologies to construct detailed molecular maps of crop species it has become possible to study much more precisely than before the possible roles of ABA by analysing the distribution of quantitative trait lici (QTL). This has been done with mapping populations of maize and wheat to study the importance of endogenous ABA in determining stomatal function, water-use efficiency and root growth in plants growing under water-stressed conditions. An F2 population of maize was mapped with 100 RFLP markers and F2 plants and their F3 progenies sampled for leaf and xylem ABA contents and stomatal conductance. Correlations using genotype mean data at QTL significant for ABA content showed that stomatal conductance was more likely to be regulated by xylem ABA content than leaf ABA content. The same maize F3 population was used to identify QTL for root growth was positively associated with root ABA content. Water-use efficiency, measured as 13C discrimination, was measured in a mapping population of doubled haploid lines of wheat. Leaf ABA concentrations were also measured. Comparison of QTL for the two traits showed that leaf ABA concentrations were unlikely to have had an effect on plant water-use efficiency in those field conditions. QTL analysis is a very powerful technique for testing the likely roles of endogenous ABA.

This article deals with use of several bioindication methods in forest decline studies within an international TEMPUS project carried out in Slovenia. The aim of the project was to introduce and connect different bioindication methods in order to improve methods and qualify the research staff working in this research field in Slovenia. The following bioindication methods were introduced or adapted for forest decline research in Slovenia: biochemical and physiological markers of air pollution / stress impact on forest trees (Graz Univ.: photosynthetic pigments, thiols, ascorbic acid, protective enzyme systems; Cambridge Univ.: plant hormones; Munich Univ.: mineral nutrition of forest trees); epiphytic lichens as indicators of air quality on forest sites (Graz Univ., Ljubljana Univ); determination of types of ectomycorrhizae as indicators of forest soil condition (Munich Univ., Ljubljana Univ.). The significance and practical use of bioindication methods in environmental studies is also discussed.

The effect of atmospheric NH3 deposition on freezing tolerance of needles of Scots pine was investigated. Needles from 3 month old seedlings and from 20-30 year old field-grown Scots pine (Pinus sylvestris L.) trees were studied. Seedlings were exposed to NH3 during the first stage of hardening in the laboratory. Field-grown trees were growing in a "clean" or an NH3 polluted area. In the 3 month old seedlings, exposure to 1000 ml 1** (-1) NH3 for 4 weeks resulted in a 40 increase of total nitrogen content. Freezing tolerance of the needles was significantly enhanced in the NH3 exposed seedlings. In the field-grown trees, current and one year old needles were studied. Freezing tolerance of the current year needles did not differ significantly between the two forest stands. However, one year old needles from the NH3 polluted stand were significantly less frost hardened from October until February. Total nitrogen content was higher in both current and one year old needles from the NH3 polluted stand. At the same time, potassium content of these needles was lower compared to the needles from the clean stand. The content of calcium, magnesium and phosphorus did not differ significantly. It was concluded that a decrease of freezing tolerance upon atmospheric NH3 was not directly related to an increased nitrogen content, but might probably be due to the nutrient imbalance of the needles.

To use alterations to epicuticular wax morphology as a successful tool in forest damage research, however, it is necessary to distinguish environmental influence and artefacts from common pollution effects. This paper gives a short review about alterations to epicuticular wax morphology of spruce needles.

Research was carried out in EMFT, II-G-10 (common oak and common hornbeam zone) and in main EMFT-s on the karst (pubescent oak and oriental hornbeam, and holly oak zones) in which forest fuel loads were determined too. Soil and structure elements were sampled and measured, stand vitality and quality were measured and evaluated. Chemical and physical analyses of soil samples were performed. The samples of precipitation's and plant material were chemically analyzed. It contains the data of normal and changed forest conditions (first measurement 1969-1981, second measurement 1991-1993). In second measurement the research that deals with tree breeding and fructification was added to the project. The aim of this recently introduced research is to determine the dynamics of flowering and phenotype damage degree. Cytogenetic and some biochemical analyses were carried out with the aim of determining and establishing methodology of work. The data base was built up and data search programs were developed. The relations of ecological and structural stand elements for normal and changed stand conditions were determined. The results achieved are the basis for building up the diagnostic stand models and the evaluation model of ecological-environmental ecosystem value. The main purpose is to support decision making on different management levels.