Heyser, Wolfgang
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Item type:Publication, Lokalisation und Regulation der sauren Invertase in mykorrhizierten Kurzwurzeln(2005-12-19); ; ; Most vascular plants live in a symbiotic association with soil fungi, the mycorrhiza. In this symbiosis, the fungus takes up nutrient salts and water from the soil and makes them accessible for the plant partner, while the plant supplies the fungus with essential carbohydrates produced in photosynthesis. As the fine fungal hyphae can penetrate and exploit the soil to a much greater extend than the plant's own root hairs, the mycorrhizal symbiosis increases both the ecological and physiological fitness of the plant. The mycorrhiza has a tremendous impact on agriculture and forestry by increasing plant growth, plant health and crop yield.The transport form of carbohydrates in most plants is sucrose, which mycorrhizal fungi are unable to take up. Invertases can convert sucrose into its component hexose sugars, glucose and fructose. They are key enzymes for sugar distribution in the plant and for nutrient exchange between organisms in the ectomycorrhizal symbiosis. Several different forms of invertases are known in plants and in saprophytic fungi, whereas most ectomycorrhizal fungi are deficient in these enzymes. The enzymatic action of plant invertases supports the fungal partner with a stable supply of hexose sugars, as these fungi are unable to use the plant sugar sucrose directly. From previous studies, the presence of invertases in the contact zone of an ectomycorrhiza, the apoplastic space, has been suspected, but was not directly demonstrated. This work focusses of a direct immunohistochemical detection of invertases in the interfacial apoplast of an ectomycorrhiza, combined with invertase activity measurements in different kinds of plant roots.Acid invertases from poplar roots (Populus tremula x Populus tremuloides, Clone T89) exhibit reaction optima in the temperature range of 50Ã ° - 65Ã °C. When assayed at their resepctive optimal temperature, invertase activity is highest in long roots and lowest in both mycorrhizal and non-mycorrhizal short roots. The difference between mycorrhizal and non-mycorrhizal short roots is only slight, but shortly after fertilization, cell-wall invertase activity is slightly higher in myorrhizal roots. This is interpreted as a sign of active transport processes across the apoplastic interface in the ectomycorhizal symbiosis.For immunization and specific antibody production, a synthetic polypeptide from a highly conservered domain of plant acid invertases was used. Both raw antiserum and affinity-purified antibody from this immunization detected poplar invertase proteins in Western Blots. The same invertase proteins were also detected by other invertase antisera obtained from other researchers for comparison. The antibodies produced here did not cross-react with fungal (Amanita) cell-wall proteins, thus enabling a specific detection of invertases at the plant-fungus interface.In semi-thin sections of a poplar-Amanita muscaria ectomycorrhiza, the invertase-specific antibodies produced a distinct positve signal at the inner boundary of the Hartig Net, precisely at the cell walls. This signal did not occur at other cortical or fungal cell walls and was most pronounced in the median part of the ectomycorrhizal root, the main zone of nutrient exchange in the symbiosis. Such a distinct reaction was not observed in non-mycorrhizal short roots.This work supports the current models of nutrient exchange in the ectomycorhizal symbiosis, which postulate the presence of an apoplastic invertase in the plant-fungus interface.doctoral thesis306 167 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Untersuchungen zur Verbesserung von Wiederaufforstungsmaßnahmen in Südkorea unter besonderer Berücksichtigung des Beitrages verschiedener Mykorrhiza-bildender Mykobionten und unterschiedlicher Bodensubstrate(2002-05-03); ; ; The aim of the present investigation was the development of a model system for an improvement of a reforestation of extreme sites. As extreme locations here in particular, waste dumps, rubble and eroded locations in South Korea were considered. Two domestic Pinus species (Pinus thunbergii and Pinus densiflora) of South Korea and as mycobionts Pisolithus tinctorius, Suillus bovinus and Rhizopogon roseolus were selected. As soil substrates mainly forest soil, sand, and rubble were tested. Additionally, compost was used as an additive to improve the used soil substrates. In particular it was checked, with which tree species and which mycorrhiza an optimal plant growth and a good mycorrhizal formation can be obtained. A special emphasis became from mycorrhizal fungi in this case on optimization of an isolation means for the extraction of suitable pure cultures, mycorrhizal roots from the field and put the choice of the suitable symbiosis partners. In order to be able to judge the effect of soil parameters onto the development of the mycorrhiza and onto the plant growth, different soil parameters were determined as well as carried out a nutrient and pollutant analysis in the shoot and roots of mykorrhizal and non-mycorrhizal plants. The developed model system proved itself suitable for the processing of the performed question formulations. It also showed the effect of the mycorrhizal formation in the experimental approaches to the inoculation as well as the optimal combination are recognizable at that between the symbiosis partners. A precise and optimized selection of mycorrhizal fungi could lead to an improved growth of woods on extreme sites.doctoral thesis240 473 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Der Effekt der Ektomykorrhiza auf die Aufnahme und Verteilung von Calcium in Sämlingen von Pinus sylvestris L.(2006-05-09); ; ; The objective of this thesis was to investigate the influence of ectomycorrhiza on the uptake and distribution of calcium in pine seedlings (Pinus sylvestris). A focal point of interest was the apoplastic permeability of the fungal sheath of the fungi Suillus bovinus and Rhizopogon roseolus. Using different methods (micro- and macroautoradiography, liquid scintillation spectrometry, atom absoption spectrometry, EDXS), the distribution of calcium within the mycorrhizae and the uptake into the shoots were examined in order to obtain detailed knowledge of the transport processes in the mycorrhizal roots.Using the radiotracer 45Ca, an apoplastic transport through the fungal sheath of the fungi Suillus bovinus and Rhizopogon roseolus could be proven. This was shown by microautoradiographs, which established radioactive marking in the cell walls of the fungal sheath, the harting net and the stele. However, a part of the calcium was precipitated by the fungi by means of exudation of oxalic acid in form of calciumoxalat, and therefore existed in a physiologically inactive form. Another part of the disposable calcium was bound to free cation-binding sites of the cell walls, and therefore temporarily unavailable for transport into the shoot. The absence of the fungal sheath and its ?buffer-effect? explains the faster transport of 45Ca into the shoot of non-mycorrhizal pine. The transport capability of calcium into the shoot was also a distinguishing factor between the two fungal partners. Rhizopogon roseolus displayed a higher calcium intake, which can be explained by its thinner fugal sheath. Additionally, using X-ray microanalysis, higher S-contents could be shown to exist in the cell walls of Suillus bovinus. This could be an indication for a higher hydrophobin accumulation and therefore also a higher hydrophobicity compared to Rhizopogon roseolus. Exposure in an aqueous milieu resulted for Suillus bovinus in lower S-contents, which can be explained by a diffusion of the hydrophobines into the surrounding medium.Experiments with different external calcium concentrations (1mM and 50 mM) showed that an increased calcium supply primarily influenced the calcium concentration in the shoots of the non-mycorrhizal pines. While the calcium was transported relatively freely into the shoot by the non-mycorrhizal roots, the ectomycorrhizae held back part of the excess calcium. Investigating the vacuolar polyphosphate granules of the fungal partners it could be shown that the composition of Suillus bovinus strongly depended on external factors. It could be proven that in the presence of a surplus of calcium, even when using cryotechiques, calcium is nevertheless present to a large degree in the polyphosphate granules.In this thesis it could be shown that the apoplastic transport of calcium through the fungal sheaths of Suillus bovinus and Rhizopogon roseolus is possible. However, a part of the calcium is held back by the mycorrhizae, and is therefore temporarily unavailable for further transport into the shoot. Most important for the transport processes in the fungal sheaths are, beside the species of the symbiotic partners, the form of the fungal sheaths and the experimental conditions.doctoral thesis237 139 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Brazilian Atlantic Rainforest Remnants and Mycorrhizal Symbiosis - Implications for Reforestation. A case stduy in Sergipe, Northeast BrazilThis work presents results of several aspects of the ecology of two Atlantic rainforest remnants in the Brazilian northeast region. The region is characterized by a marked rainfall seasonality, and therefore sampling was carried out in the two periods. Sampling was also carried out in the adjacent region of each fragment, occupied by coconut plantations in both sites. Aiming to investigate the potential of native mycorrhizal species on forest regeneration, the assessment of mycorrhizal symbiosis in roots of seedling and trees was performed, as well as the analysis of the spatial distribution of inoculum. Arbuscular mycorrhizal fungi (AMF) was dominant, but AMF inoculum was not excluded from the plantation plots. In fact, spore species richness was higher than in the forest plots. AMF spore species richness and root colonization levels were higher in the upper layers of the soil, similarly to the nutrient and root biomass. Seedling recruitment was lower in the plantation than in forest plots. Seedling root mycorrhizal colonization was spatially uneven. Analysis of seedling roots from four different native tree species revealed a variable pattern of root colonization. Some of these species presented high colonization levels by dark septate endophyte. The analysis of native tree roots revealed also that ectomycorrhizal inoculum, although rare, is present in these forests, as one of the selected species, Cocoloba rosea was ectomycorrhizal. Preliminary experiments intending to test the ability of native AMF inoculum in promoting seedling growth were performed with a native legume tree species, Bowdichia virgilioides. The positive effects of AMF inoculation on plant growth, even with native mixed inoculum, suggests native inoculum can be successfully used on restoration of these deforested regions. Moreover, the high AMF colonization of the pioneer species should be managed to maximize the effects of inoculation of B. virgilioides seedlings in field conditions.doctoral thesis393 198 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Der Einsatz von mykorrhizierten Feuchtgebietspflanzen in Bodenfiltern zur Reinigung von Oberflächenabwässern(2010-11-25); ; ; Use of mycorrhizal wetland plants to improve constructed wetlands for decentralised treatment of surface runoff was studied in several pilot experiments. Selected helophytes, grown in a suitable filter substrate, were inoculated with arbuscular mycorrhizal fungi (AMF) and treated with pollutants detected in surface runoff. Tested pollutants were: heavy metals (copper, zinc), petroleum hydrocarbons (C12, C15, C20), monoaromatics (toluene, cyclohexane), fuel additive MTBE, PAHs (acenaphthene, phenanthrene) and herbicide 2,4-D. Effect of de-icing salt was also tested. Purple loosestrife (Lythrum salicaria) was chosen for extensive investigations. Experimental data showed that planting improved significantly the efficacy of treatment. Negative influence on plant vigour and percentage of root colonisation was only demonstrated for heavy metals and salt. Mycorrhiza increased resistance of plants and reduced uptake of heavy metals. Eluviation of Copper was little and was further reduced by planting. Studies on depletion of petroleum hydrocarbons and PAHs result no differences between mycorrhizal and non-mycorrhizal variants, but positive effect of planting was proven. AMF-colonisation was not inhibeted by waterlogging and improved plant vigour and production of biomass. Although the retention capacity of AMF for heavy metals and influence of mycorrhization on depletion of organic pollutants could not be fully elucidated in this work, the use of mycorrhizal wetland plants to improve the cleaning capacity of constructed wetlands is recommended because of their positive effect on plant vigour and biomass formation.doctoral thesis364 336 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Beurteilung der natürlichen Abbau- und Rückhalteprozesse der Schadstoffgruppen MKW und BTEX in der wasserungesättigten Bodenzone - Ergebnisse aus Untersuchungen im Labor-, Technikums- und Feldmaßstab(2006-07-21); ; ; The potentials and limitations of natural degradation and sorption processes of petroleum hydrocarbon and BTEX contaminants in the vadose zone were investigated in laboratory and technical scale as well as in field scale.On a former military site, soil investigations and a monitoring of soil air, seepage water and groundwater were carried out for three years. Although the contaminants in soil were inhomogenously distributed, a decrease in the concentration of petroleum hydrocarbons attributable to biodegradation, volatilization and leaching processes was observed in several sampling areas. In particular, microbial degradation processes were confirmed by soil air and ground water monitoring. The microbial activity at the site is limited by low nutrient concentrations and a low pH-value. Batch experiments with disturbed and homogenised soil samples showed an increase of the pH value up to 7 following the addition of a calcareous buffering agent, although column experiments demonstrated that the amendment of the soil pH affected only the upper soil layer. The stimulation of nutrient ratios caused a higher degradation rate of petroleum hydrocarbons and BTEX, but also a leaching of nitrate and ammonia by seepage water.The potentials of natural degradation processes and of possible stimulation enhancement could be confirmed through Batch experiments. Column experiments with disturbed and undisturbed soil samples evidenced transport and leaching processes of contaminants, providing at the same time a measurement of the effectiveness of stimulation activities in relation to the soil depth. For Upscaling laboratory experiments to field scale, options and limitations of the test systems have to be further considered.doctoral thesis308 1134 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Gassensorische Untersuchungen mikrobiell kontaminierter Materialoberflächen(2008-05-19); ; ; Microbial contaminations in space stations present a major risk for the crew and the construction materials. In order to set guidelines for using gas-sensing to verify these microbial contaminations, spaceship components were contaminated with micro-organisms and investigated using the Electronic nose ENO-1. Under laboratory conditions the gas sensing experiment to identify the species, the kind of substrate or material, and the composition of a mixed population as influencing factors for variance in the microbial emissions was successful. The emissions are composed of the outgassing from substrate or material and the gaseous products of the microbial metabolism. Microbial emissions are further affected by the age or physiological state of a culture and interactions in mixed populations. The many influencing factors lead to high variability of the emissions from a microbial contamination and hinder the correct classification. Additionally, changing background conditions and low concentrations of microbial emissions complicate gas-sensing monitoring for microbial contamination in space stations.doctoral thesis277 224 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Der Einsatz mykorrhizierter Gehölze in biologischen Sanierungsverfahren unter dem Aspekt TNT-belasteter Böden(2003-04-25); ; ; The present work concentrates on the potential application especially of mycorrhizal plants in remediation of TNT-contaminated soils. Provided that plants clean up soils, the following experiments were carried out: :br:The degradation of TNT in rhizosphere soil was tested in experiments with ectomycorrhizal associations of :i: Pinus sylvestris/Pisolithus tinctorius :/i: and :i: Populus tremula/Hebeloma spec.:/i:, cultivated in rhizotron systems. In addition, the investigations involved the ligninolytic white rot basidiomycete :i: Pleurotus ostreatus :/i: which is able to degrade TNT via excretion of lignin and manganese peroxidase. Furthermore, uptake and translocation activity of TNT in mycorrhizal and non-mycorrhizal plants (:i: Pinus sylvestris/Pisolithus tinctorius :/i:) were examined using ringlabelled :sup:14:/sup:C-TNT. Ectomycorrhiza can be used for effective remediation of soil provided plants and fungi are tolerant or resistant to toxic contaminants. Because less is known of phytotoxicity thresholds of TNT and its metabolites in soils. In this context the effects of TNT and transformation products on growth and development of :i: Pinus sylvestris/Pisolithus tinctorius :/i: mycorrhiza were investigated. :br:The studies allow the conclusion, that mycorrhizal plants have the capacity to remediate TNT-contaminated soils. Most efficiency may be expected at sites with shallow contamination, where TNT and metabolites were treated in the rhizosphere by microbial activity and by root uptake. Uptake, accumulation and binding of TNT and its transformation products into plants seem to be dependent on plant species and plant organs.doctoral thesis436 328 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Vergleichende Untersuchungen zur biologischen Aktivität von Chitosanen in Relation zu ihren physikalisch-chemischen Eigenschaften(2016-04-08); ; ; Chitosans are a diverse group of biopolymers, which are widely used in different fields of application for years. They are appreciated and used especially because of their antimicrobial effects combined with their biocompatible properties. However, details of the correlation between their physical-chemical characteristics and biological effects (e.g. antimicrobial effect) have not been fully understood yet. In the following thesis the antimicrobial properties were examined with mold fungi as well as with gram-positive and gram-negative bacteria. Furthermore, the biocompatibility was proven with a plant assay and the physical-chemical properties of chitosan were systematically investigated. The results of the investigations on mold fungi and bacteria allow the conclusion that chitosan has no antifungal capacities. Furthermore the mold fungi are able to use the chitosan as carbon resource. Certainly, chitosans operated as an inhibitor to the group of bacteria. They acted biostatical and bactericide, which led to a structural membrane damage of E. coli. However, there was no indication of a different effect on gram-positive bacteria compared to gram-negative bacteria. The effect of chitosans is presumably more affected by bacteria and their adaptation to the environment rather than by the composition of the membrane structure. It was shown that the marine gram-negative bacteria V. fischeri was less affected in the occurrence of luminescent than the bacteria E. coli (gram-negative) and B. subtilis (gram-positive) in their dehydrogenase activity. The biocompatibility is guaranteed unrestricted as long as the pH is neutral to alkaline. Chitosans will form micelles or aggregates under these pH conditions, which significantly reduces their bioavailability. Effects in eukaryotic test systems under acetic pH conditions demonstrated, that the chitosan significantly disturbed the growth of the plant L. minor. Additionally, no growth recovery was observed even several weeks after the treatment. No influence of the molecular weight of the Chitosans on inhibition effects could be found for the correlation of the physical-chemical properties with all EC values over all experiments. On the other hand it could be shown that the degree of acetylation (and additionally combined with the amount of acetylated units) and the pattern of acetylation might influence the impact of chitosan on biological effects. A low degree of acetylation or a low-numbered pattern of acetylation inhibited the growth of bacteria most clearly, whereas a high degree of acetylation or a high-numbered pattern of acetylation inhibited the growth of L. minor most effectively. Complete biocompatibility can probably be achieved by adaption of these characteristics of chitosan.doctoral thesis279 320 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Die Bedeutung ektotropher Mykorrhiza fuer die Naehrstoffversorgung von Nothofagus obliqua. Untersuchungen unter Beruecksichtigung der Boden- und Naehrstoffbedingungen der Nothofagus-Waelder in Suedchile im Hinblick auf Wiederaufforstung und nachhaltige Forstwirtschaft(2001-06-08); ; ; Nothofagus species form the most important native constituents in the temperate humid forests of southern Chile. The presented work concentrates on the evaluation of the relevance of several specific and non-specific ectomycorrhiza for Nothofagus. First, a general survey of ectomycorrhiza found in association to N. obliqua and P. radiata near Valdivia (Chile) is presented. Further work concentrated on the mycorrhizal fungi Austropaxillus boletinoides, Boletus loyo, Austropaxillus statuum, Cenococcum geophilum, Paxillus involutus, Pisolithus tinctorius, and Descolea antartica. The extra-cellular and membrane bound phosphatase activity was determined in cultured mycelium, roots and entire mycorrhiza under different external parameters and growth conditions. Phosphatase activities of mycorrhiza-associations are of increased interest in areas of limited P supply. Extra-cellular and membrane bound phosphatase activity (PA) were quantified at different pH-values (3-7) in isolated cultures of A. boletinoides, P. involutus, P. tinctorius, D. antartica, and C. geophilum, which had been adapted to grow in media with varying concentrations of dissolved P. For the detection of membrane bound PA in fungal hyphae, we compared the pNPP-method with a newly developed method based on enzyme activated fluorescence of ELF-97 substrate and image processed confocal Laser-Scanning-Microscopy. For membrane bound PA, the fluorescence based method not only reproduced qualitatively the results obtained by pNPP, but additionally contributed valuable information about the structure and distribution of the phosphatase spots in the fungi. The ELF-97 method also provided reliable properties to be used for the determination of PA even in mycorrhizal and non-mycorrhizal roots of N. obliqua. In conclusion the observations underline that positive effects of mycorrhiza associations for the plant highly depend on the specific partners, the specific nutrient, and the specific external conditions (pH).doctoral thesis406 135