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.

In 1992, a monitoring survey on a national scale was carried out using Hypogymnia physodes (L.) Nyl. as a biomonitor for trace element air pollution. The primary aim was to analyse epiphytic lichens collected at 86 sampling locations of the 16 x 16 km bioindication grid using k(0)-based instrumental neutron activation analysis (k(0)-INAA), and X-ray fluorescence spectrometry (XRF) for sulphur and lead, to obtain information about the levels of elements in the atmosphere and to identify significant pollution sources. The geographical concentration patterns of the trace elements obtained from the lichen data were mapped and compared with the index of atmospheric purity (IAP) calculated on the basis of data from lichen thalli type mapping, obtained on a more dense bioindication grid in 1991. The results obtained showed good agreement between the mapping of sulphur and trace elements with the status of lichen vegetation. The most exposed regions with elevated trace element levels and lower values of IAP were in the north-western Alpine part of Slovenia which coincides with high precipitation, and in the east of Slovenia, where many local pollution sources are situated.

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.

Tissue specific localization of soluble secondary metabolites was demonstrated in ectomycorrhizae and uninfected roots of Picea abies, Larix decidua, Pinus sylvestris and Abies alba. Compounds were analysed by HPLC and by histochemical methods. Specific distribution and age-dependent changes were observed with several metabolites. For catechin corresponding patterns were found within the cortex of all investigated conifers. Levels of this metabolite were highest within the apical cortex cells and decreased on aging of the tissue. In spruce contents of catechin showed evident seasonal changes. Stilbene glucosides were detected within the pericycle of spruce roots and as well the phloem tissue of larch with levels increasing during root development. In larch two anthocyanins accumulated in the calyptra. In older tissues of larch roots larixin-glucosid and quercetin-rhamnosid were detected, the latter with highest levels in the phloem tissue. For cell wall bound ferulic acid increasing levels could be found concomitant with the development of the root.

Work was carried out to investigate the effect of pollution on the needle cytokinin content of mature Picea abies (L.) Karst individuals. Needles were collected from trees growing at two sites, one polluted and relatively non-polluted, in central Slovenia. After ethanolic extraction and purification, the needle cytokinin extracts were separed by reverse-phase HPLC. Cytokinin content was analysed using four direct ELISA techniques specific for Z-, DHZ- and iP-type cytokinins and the O-glucoside conjugate of Z. Results showed a trend towards the accumulation of cytokinins in needles from trees subject to high levels of atmospheric pollution, particulary with respect to ribotide derivatives. No difference was found in the (OG)Z content between polluted and non-polluted samples. The results are discussed with respect to the origins of the observed accumulation.

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.

This paper deals with presenting a broad range of possibilities, which can be used with computer equipment by deriving, interpreting and processing forest data. Different rates of generalized data from the forest inventory can be used as a criterion in preparing different solutions. So this data strongly influences decision making processes. The paper also presents cost analysis and multi-criteria evaluation methods.

Cytokinins were analysed by a combined HPLC-ELISA method in needles of Norway spruce seedlings. The seedlings were grown in vitro on sterile or nonsterile soil substrates from two differently polluted forest research plots. Difference were predominantly found in the isopentenyladenine-type of cytokinins. These were elevated in seedlings, grown on polluted soils in comparison to those, grown on soils from the unpolluted plot. A possible explanation might be in the change of the metabolism in the roots due to pollution stress (when grown on sterilized substrates) or in change of the mycorrhizosphere organisms (when grown on nonsterile soil substrates). The model system using Norway spruce seedlings as tester organisms for soil pollution is discussed.

The concentrations of potassium were determined in: (a) the last formed wood, (b) the vascular cambial zone with conductive (noncollapsed) phloem, (c) the youngest nonconductive (collapsed) phloem and the (d) oldest nonconductive phloem, by atomic absorption flame spectroscopy in three unaffected and three heavily affected silver fir (Abies alba Mill.) trees. A commercial conditiometer and own devised Tree Tester were used to determine the electrical resistance (ER). The relationship between the ER of living tissues and K content was investigated. The tissues of unaffected trees were generally characterized by a higher K content and corresponding lower ER. In all trees the K content was highest and ER lowest in the vascular cambial zone with conducting phloem, followed by nonconducting phloem and youngest xylem.