Clonal Re-Introduction of Endangered Plant Species: The Case of German False Tamarisk in Pre-Alpine Rivers

The scope of re-introduction as a measure for plant species protection is increasing, but as long as no standardized methods are available, species-specific assessments are necessary to determine whether seeds, adult plants or plant fragments should be used. The endangered German False Tamarisk (Myricaria germanica), which occurs on gravel bars along pre-alpine rivers, is difficult to grow from seeds. Thus, propagation of stem cuttings was investigated as an alternative method. Experiments were conducted in a greenhouse and a field site with three treatments: cutting length 5 or 10 cm, vertical burial 5 or 10 cm, and water level low or high. Plants grown in the greenhouse were transplanted to the River Isar to test establishment of rooted cuttings on gravel bars. The cuttings in the greenhouse showed high survival (34-96 %). Survival and biomass production were greatest for 10-cm cuttings buried at 10-cm depth, while only one of the 5-cm cuttings survived at this depth, and no significant effect of variation in water level was observed. None of the cuttings transplanted to field sites survived, most likely because of drought stress and competition. We conclude that for re-introduction of Myricaria germanica rooted cuttings can be easily produced in large quantities, while transplantation to near-natural environments has to be improved to reduce mortality.     

Symptom patterns, and perceptual and cognitive styles in subjects with multiple chemical sensitivity (MCS)

Multiple chemical sensitivity (MCS) is defined as a syndrome with multiple medically unexplained symptoms attributed to low levels of chemically unrelated substances in the environment. The etiology of this syndrome is still unclear. As MCS may be conceptualized as an atypical type of somatoform disorder, the purpose of the study was to examine whether MCS subjects show symptom patterns, personality traits, and perceptual and cognitive styles as typically found in somatoform patients. Nonsensitive controls (n=36) were compared to subjects with moderate (n=35) and high (n=35) MCS intensity with self-report psychological questionnaires and structured interviews for depression and somatoform disorders. The high MCS group scored significantly higher than the other two groups on self-report scales for somatoform symptoms and depression. Moreover, high MCS was strongly associated with the diagnosis of somatoform disorder, and weaker but still significantly with depression. In a stepwise multiple regression analysis, cognitions about environmental threat, trait anxiety, focus on autonomic sensations, and general environmental sensitivity predicted MCS symptoms in the total sample, explaining 53% of the variance. These results support the hypothesis that trait negativity and mechanisms of symptom perception and symptom amplification contribute to the enhanced symptom reports of MCS individuals.     

A new conceptual model for the fate of lignin in decomposing plant litter

Lignin is a main component of plant litter. Its degradation is thought to be critical for litter decomposition rates and the build-up of soil organic matter. We studied the relationships between lignin degradation and the production of dissolved organic carbon (DOC) and of CO2 during litter decomposition. Needle or leaf litter of five species (Norway spruce, Scots pine, mountain ash, European beech, sycamore maple) and of different decomposition stage (freshly fallen and up to 27 months of field exposure) was incubated in the laboratory for two years. Lignin degradation was followed with the CuO method. Strong lignin degradation occurred during the first 200 incubation days, as revealed by decreasing yields of lignin-derived phenols. Thereafter lignin degradation leveled off. This pattern was similar for fresh and decomposed litter, and it stands in contrast to the common view of limited lignin degradation in fresh litter. Dissolved organic carbon and CO2 also peaked in the first period of the incubation but were not interrelated. In the later phase of incubation, CO2 production was positively correlated with DOC amounts, suggesting that bioavailable, soluble compounds became a limiting factor for CO2 production. Lignin degradation occurred only when CO2 production was high, and not limited by bioavailable carbon. Thus carbon availability was the most important control on lignin degradation. In turn, lignin degradation could not explain differences in DOC and CO2 production over the study period. Our results challenge the traditional view regarding the fate and role of lignin during litter decomposition. Lignin degradation is controlled by the availability of easily decomposable carbon sources. Consequently, it occurs particularly in the initial phase of litter decomposition and is hampered at later stages if easily decomposable resources decline.     

Teil 2: PCDD/F,Biphenyle und Organochlorpestizide in Frauenmilch

After the discovery of high dioxin levels (>100 000 ng TE BGA/kg) in copper slag (Kieselrot) from a specific chlorinating roasting process performed in Marsberg, human milk samples from mothers living in Marsberg were analyzed for polychlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) and other pollutants. PCDD/F levels in all samples were comparable with levels in human milk samples from other locations in the Federal Republic of Germany. An increase in congeners, especially of those predominating in ?Kieselrot“, could not be measured. Although several thousand tons of dioxin contaminated copper slag still lie on the slagheap, a higher burden in human milk from Marsberg could not be observed.     

Dynamics of arbuscular mycorrhizal symbiosis in heavy metal phytoremediation: meta-analytical and conceptual perspectives

To estimate dynamics of arbuscular mycorrhizal (AM) symbiosis in heavy metal (HM) phytoremediation, we conducted a literature survey and correlated HM uptake and relative plant growth parameters from published data. After estimating AM feedback responses for these parameters at low and high soil-HM concentration intervals, we determined that the roles of AM symbiosis are characterized by (1) an increased HM phytoextraction via mycorrhizospheric 'Enhanced Uptake' at low soil-HM concentrations, and (2) a reduced HM bioavailability via AM fungal 'Metal-Binding' processes at high soil-HM levels, hence resulting in increased plant biomass and enhanced plant tolerance through HM stress-avoidance. We present two conceptual models which illustrate the important compromise between plant growth, plant HM uptake and HM tolerance, and further emphasize the importance of AM symbiosis in buffering the soil environment for plants under such stress conditions.     

Past On-Site Experience,Crowding Perceptions,and Use Displacement of Visitor Groups to a Peri-Urban National Park

Past on-site experience was linked to the crowding perceptions and use displacement of 383 on-site visitors to the peri-urban Danube Floodplains National Park, Austria. Three visitor groups were determined according to their area experience: local residents from Vienna and rural communities, having the highest level of experience; regional visitors from the city and eastern Austria; and tourists from Austria and abroad with the lowest degree of experience. Crowding perceptions were significantly different across the user groups. More than 50% of local residents perceived the national park as crowded, whereas only 27% of regional visitors and 19% of tourists reported such an evaluation. Even among local residents and regional visitors, respondents with more on-site experience expressed a greater impression of a crowded park. Differences in crowding evaluations between local rural and urban residents and between regional rural and urban visitors were not found. For 27% of local residents and 15% of regional visitors, use levels were so unacceptable that they displaced temporally and spatially, whereas use displacement was relatively irrelevant for tourists. The use displacement strategies involved differ among the three user groups. Management implications were discussed, taking the specific situation of the small national park on the urban-rural fringe into consideration.     

Solid state fermentation of olive mill residues by wood- and dung-dwelling Agaricomycetes: Effects on peroxidase production,biomass development and phenol phytotoxicity

The in vivo conversion of dry olive mill residue (DOR) by wood- and dung-dwelling fungi − Auricularia auricula-judae, Bjerkandera adusta and Coprinellus radians − increases peroxidase secretion up to 3.2–3.5-fold (∼1.3, 3.5 and 7.0 U g⁻¹ DOR for dye-decolorizing peroxidase, manganese peroxidase and aromatic peroxygenases, respectively). The incubation of DOR with these fungi produced a sharp decrease in total phenolic content (100% within 4 wk), a reduction in phytotoxicity as well as a certain degree of plant growth caused by the stimulating effect of fungal-treated DOR. These findings correlate with a characteristic shift in the fragmentation pattern of water-soluble aromatics (detected at 280 nm) from low (0.2, 1.5 and 2.2 kDa, respectively) to high molecular mass (35 to >200 kDa), which demonstrates the presence of a polymerization process. Phenol-rich agricultural residues are a useful tool for enzyme expression and production studies of peroxidase-producing Agaricomycetes which could make DOR a valuable organic fertilizer.     

Effects of ozone impact on the gas exchange and chlorophyll fluorescence of juvenile birch stems (Betula pendula Roth.)

Effects of ozone impact on gas exchange and chlorophyll fluorescence of juvenile birch (Betula pendula) stems and leaves were investigated. Significant differences in the response of leaves and stems to ozone were found. In leaves, O3 exposure led to a significant decline in photosynthetic rates, whereas stems revealed an increased dark respiration and a concomitant increase in corticular photosynthesis. In contrast to birch leaves, corticular photosynthesis appeared to support the carbon balance of stems or even of the whole-tree under O3 stress. The differences in the ozone-response between leaves and stems were found to be related to ozone uptake rates, and thus to inherent differences in leaf and stem O3 conductance.     

Verbleib von spurenschadstoffen bei der methylesterherstellung aus altspeisefett im technikumsmaßstab

Aims and Scope

In Germany, 120,000 tons per year of waste edible fats are collected from the catering and the food industry Until recently, these fats have widely been used as a nutritional additive for poultry and other animals fodder. Due to the BSE crisis and some affairs based on dioxins in feeding stuff, waste fats are now barely used as fodder. Currently, these fats substitute fresh vegetable oils in the chemical industry and are used as raw material for the production of biodiesel. Therefore, alternative fields of application are required. In this context, the Deutsche Bundesstiftung Umwelt (DBU) is sponsoring a joint research project which deals with the production and testing of cooling lubricants based on monoesters made from waste edible fats.

Methods

In a first step, characteristics and quality of wasteedible fats of different origins were chemically analysed and monitored. The investigations covered the following fat specific parameters: total contamination, sulphate ash, water content, peroxide number, iodine value, kinematical viscosity, neutralisation number (free fatty acids) and fatty acid spectra. In the next step, a process development/optimisation was carried out for the production of methylesters based on the raw material waste fat, leading to the construction of a pilot plant. To investigate the fate of trace pollutants during the production process of waste-fat methylester, samples were systematically contaminated with polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and the elements Al, Cd, Cr, Cu, Ni, P, Pb, Sn, and Zn. These contaminated fat samples were transesterified in laboratory scale. The primary and by-products were analysed subsequently.

Results

Valuable hints on the design of the technical process of fatty adid methylester production based on waste edible fats were gained by regarding the fat specific parameters. For example, filtration and dewatering of the waste fats proved necessary. The saturated fatty acids, most wanted for the production of cooling lubricants due to their high oxidation stability, were present in the range of 11,3% to 31,6%. Due to the low content of free fatty acids, a base catalysed process occurred more suitable for the transesterification of the waste edible fats. Trace analytical investigations concerning inorganic and organic pollutants proved a low basic contamination of the waste edible fats. Experiments with systematic contamination of the fats indicated an accumulation of the heavy metals in the glycerol phase during the transesterification process, whereas the organic pollutants were detected in the methylester fraction by amounts of 80% to 95%.

Outlook

In a next step, the further processing of the methylesters to monoesters with alcohols of the chain length C2 to C8 will be presented. Associated results of chemical-analytical investigations on the process and the application of the cooling lubricants will also be given.