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The fungus Boeremia sambuci-nigrae (formerly Phoma sambuci-nigrae) causes the corymb wilt disease in elder (Sambucus nigra L.). Here, we assessed the genetic diversity of fungi within the Phoma-complex which associate with commercially cultivated elder in Styria (Austria). We sampled leaves, corymb stalks and berries of elder trees in one organically and in four conventionally managed orchards. In each orchard an area was left untreated allowing a sampling of fungicide treated and untreated trees. Nineteen taxa in the Phoma-complex were isolated and identified based on ITS and LSU nucDNA sequences. One isolate is closely related to Chaetosphaeronema, whereas the majority of the strains belong to the genera Epicoccum and Boeremia in Didymellaceae. Six isolates are monophyletic with Boeremia sambuci-nigrae. The results indicate a varying effectiveness of fungicide treatment for the different fungal groups investigated. The diverse distribution of isolates among the sampling sites suggests the influence of treatment effects and possibly also of climatic conditions.

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Eukaryote genomes contain multiple copies of nuclear ribosomal DNA (nrDNA) harboring both highly conserved and variable regions. This has made nrDNA the most popular genetic marker for phylogenetic studies and the region of choice for barcoding projects. Furthermore, many scientists believe that all copies of nrDNA within one nucleus are practically identical due to concerted evolution. Here, we investigate the model plant species Arabidopsis thaliana for intragenomic variation of the internal transcribed spacer (ITS) region of nrDNA. Based on a modified deep sequencing approach, we provide a comprehensive list of ITS polymorphisms present in the two most widely used accessions of A. thaliana-Col-0 and Ler. Interestingly, we found that some polymorphisms are shared between these genetically very distinct accessions. On the other hand, the high number of accession-specific polymorphisms shows that each accession can be clearly and easily characterized by its specific ITS polymorphism patterns and haplotypes. Network analysis based on the detected haplotypes demonstrates that the study of ITS polymorphism patterns and haplotypes is an extremely powerful tool for population genetics. Using the methods proposed here, it will now be possible to extend the traditionally species-bound barcoding concept to populations.

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This study deals with the effect of altitudinal variation on the content of phenolic compounds in three traditional herbal plants, which are also consumed as food in Central Europe. Herbs of Calluna vulgaris (L.) HULL, flowers and fruits of Sambucus nigra L., and berries of Vaccinium myrtillus L. collected in the Naturpark Solktaler (Austria) were extracted using accelerated solvent extraction (ASE). Identification and quantification of the constituents in the polar extracts (methanol 80%, v/v) were achieved by means of RP-HPLC-PDA and/or LC-PDA-MS analysis with external standards. 3,5- O-Dicaffeoylquinic acid was identified in flowers of S. nigra for the first time. Rising concentrations of flavonoids and especially flavonol-3- O-glycosides with adjacent hydroxyl groups in ring B in C. vulgaris and S. nigra with increasing altitude were observed. Anthocyanins from the berries of both S. nigra and V. myrtillus occurred in decreasing amounts with rising altitude. C. vulgaris showed the best radical scavenging capacity based on the DPPH assay.

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We investigated effects of nitrogen (N) fertilizer and canopy position on the allocation of N to Rubisco and chlorophyll as well as the distribution of absorbed light among thermal energy dissipation, photochemistry, net CO2 assimilation and alternative electron sinks such as the Mehler reaction and photorespiration. The relative reduction state of the primary quinone receptor of photosystem II (QA) was used as a surrogate for photosystem II (PSII) vulnerability to photoinactivation. Measurements were made on needles from the lower, mid and upper canopy of 21-year-old Pinus radiata D. Don trees grown with (N+) and without (N0) added N fertilizer. Rubisco was 45 to 60% higher in needles of N+ trees than in needles of N0 trees at all canopy positions. Chlorophyll was approximately 80% higher in lower- and mid-canopy needles of N+ trees than of N0 trees, but only approximately 20% higher in upper-canopy needles. Physiological differences between N+ and N0 trees were found only in the lower- and mid- canopy positions. Needles of N+ trees dissipated up to 30% less light energy as heat than needles of N0 trees and had correspondingly more reduced QA. Net CO2 assimilation and the proportions of electrons used by alternative electron sinks such as the Mehler reaction and photorespiration were unaffected by N treatment regardless of canopy position. We conclude that the application of N fertilizer mainly affected the biochemistry and light-use physiology in lower- and mid-canopy needles by increasing the amount of chlorophyll and hence the amount of light harvested. This, however, did not improve photochemistry or safe dissipation, but increased PSII vulnerability to photoinactivation, an effect with likely significant consequences during sunflecks or sudden gap formation.

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Photoprotection, light harvesting and light utilisation were investigated as a function of variation in N supply and canopy position in 21-year-old Pinus radiata D. Don. Chlorophyll fluorescence, gas exchange and photoprotective compounds were measured on lower, middle and upper canopy needles in trees receiving N fertiliser and in control trees not receiving N fertiliser. Irrespective of canopy height, additional N increased the light-harvesting capacity through greater contents of chlorophyll, neoxanthin and lutein, but did not affect light-utilisation processes, such as effective quantum yield of PSII or rates of net CO2 assimilation. Additional N fertiliser did not affect the concentrations of the measured photoprotective carotenoids (violaxanthin, antheraxanthin, zeaxanthin, α-carotene and ß-carotene) or antioxidants (ascorbic acid, glutathione and α-tocopherol); however, carotenoids and antioxidants were strongly affected by canopy height and increased in concentration with increasing canopy height. The present study found that pools of photoprotective carotenoids and antioxidants were not driven by imbalances in light-harvesting and light-utilisation processes, but rather by gradients in light.