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Berlin Brandenburg

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  • 1
    Language: English
    In: Plant and Soil, 2013, Vol.364(1), pp.287-301
    Description: Background and aims: Nitrous oxide (N sub(2)O) and methane (CH sub(4)) can be emitted from surfaces of riparian plants. Data on the emission of these greenhouse gases by upland trees are scarce. We quantified CH sub(4) and N sub(2)O emissions from stems of Fagus sylvatica, an upland tree, and Alnus glutinosa, a riparian tree. Methods: The gas fluxes were investigated in mesocosms under non-flooded control conditions and during a flooding period using static chamber systems and gas chromatographic analyses. Results: Despite differences in the presence of an aerenchyma system, both tree species emitted N sub(2)O and CH sub(4) from the stems. Flooding caused a dramatic transient increase of N sub(2)O stem emissions by factors of 740 (A. glutinosa) and even 14,230 (F. sylvatica). Stem emissions of CH sub(4) were low and even deposition was determined (F. sylvatica controls). The results suggest that CH sub(4) was transported mainly through the aerenchyma, whereas N sub(2)O transport occurred in the xylem sap. Conclusions: For the first time it has been demonstrated that upland trees such as F. sylvatica clearly significantly emit N sub(2)O from their stems despite lacking an aerenchyma. If this result is confirmed in adult trees, upland forests may constitute a new and significant source of atmospheric N sub(2)O.
    Keywords: Methane ; Nitrous oxide ; Soil and stem emission ; Alnus glutinosa ; Fagus sylvatica ; Flooding
    ISSN: 0032-079X
    E-ISSN: 1573-5036
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  • 2
    Language: English
    In: Plant and Soil, 2013, Vol.368(1), pp.519-534
    Description: Background and aims: Litter decomposition is regulated by e.g. substrate quality and environmental factors, particularly water availability. The partitioning of nutrients released from litter between vegetation and soil microorganisms may, therefore, be affected by changing climate. This study aimed to elucidate the impact of litter type and drought on the fate of litter-derived N in beech seedlings and soil microbes. Methods: We quantified super(15)N recovery rates in plant and soil N pools by adding super(15)N-labelled leaf and/or root litter under controlled conditions. Results: Root litter was favoured over leaf litter for N acquisition by beech seedlings and soil microorganisms. Drought reduced super(15)N recovery from litter in seedlings thereby affecting root N nutrition. super(15)N accumulated in seedlings in different sinks depending on litter type. Conclusions: Root turnover appears to influence (a) N availability in the soil for plants and soil microbes and (b) N acquisition and retention despite a presumably extremely dynamic turnover of microbial biomass. Compared to soil microorganisms, beech seedlings represent a very minor short-term N sink, despite a potentially high N residence time. Furthermore, soil microbes constitute a significant N pool that can be released in the long term and, thus, may become available for N nutrition of plants.
    Keywords: Litter types ; Root litter ; Leaf litter ; Decomposition ; Microbial biomass ; Plant N metabolism ; Soil N pools ; N recovery
    ISSN: 0032-079X
    E-ISSN: 1573-5036
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  • 3
    Language: English
    In: Plant and Soil, 2013, Vol.369(1), pp.657-668
    Description: Aims: Our aims were to characterize the fate of leaf-litter-derived nitrogen in the plant-soil-microbe system of a temperate beech forest of Southern Germany and to identify its importance for N nutrition of beech seedlings. Methods: super(15)N-labelled leaf litter was traced in situ into abiotic and biotic N pools in mineral soil as well as into beech seedlings and mycorrhizal root tips over three growing seasons. Results: There was a rapid transfer of super(15)N into the mineral soil already 21 days after tracer application with soil microbial biomass initially representing the dominant litter-N sink. However, super(15)N recovery in non-extractable soil N pools strongly increased over time and subsequently became the dominant super(15)N sink. Recovery in plant biomass accounted for only 0.025 % of super(15)N excess after 876 days. After three growing seasons, super(15)N excess recovery was characterized by the following sequence: non-extractable soil N〉〉extractable soil N including microbial biomass〉〉plant biomass〉ectomycorrhizal root tips. Conclusions: After quick vertical dislocation and cycling through microbial N pools, there was a rapid stabilization of leaf-litter-derived N in non-extractable N pools of the mineral soil. Very low super(15)N recovery in beech seedlings suggests a high importance of other N sources such as root litter for N nutrition of beech understorey.
    Keywords: Nitrogen cycling ; Beech ; 15N-labelled leaf litter ; 15N tracing ; Microbial biomass ; Ectomycorrhiza
    ISSN: 0032-079X
    E-ISSN: 1573-5036
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  • 4
    Language: English
    In: Oecologia, 2014, Vol.174(3), pp.839-851
    Description: Plant carnivory represents an exceptional means to acquire N. Snap traps of Dionaea muscipula serve two functions, and provide both N and photosynthate. Using 13 C/ 15 N-labelled insect powder, we performed feeding experiments with Dionaea plants that differed in physiological state and N status (spring vs. autumn plants). We measured the effects of 15 N uptake on light-saturated photosynthesis ( A max ), dark respiration ( R D ) and growth. Depending on N status, insect capture briefly altered the dynamics of R D / A max , reflecting high energy demand during insect digestion and nutrient uptake, followed by enhanced photosynthesis and growth. Organic N acquired from insect prey was immediately redistributed, in order to support swift renewal of traps and thereby enhance probability of prey capture. Respiratory costs associated with permanent maintenance of the photosynthetic machinery were thereby minimized. Dionaea’s strategy of N utilization is commensurate with the random capture of large prey, occasionally transferring a high load of organic nutrients to the plant. Our results suggest that physiological adaptations to unpredictable resource availability are essential for Dionaea’s success with regards to a carnivorous life style.
    Keywords: Plant carnivory ; Cost/benefit ; Photosynthetic efficiency ; Respiration ; Nitrogen uptake
    ISSN: 0029-8549
    E-ISSN: 1432-1939
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  • 5
    Language: English
    In: Planta, 2015, Vol.241(3), pp.579-589
    Description: Byline: Bin Liu (1), Heinz Rennenberg (1,2), Jurgen Kreuzwieser (1) Keywords: Nitrate; Nitrate reductase; Nitric oxide emission; Oxygen deficiency; Root-to-shoot transport Abstract: Main conclusion Hypoxia leads to NO formation in poplar roots. Additionally, either NO or a NO derivative is transported from the roots to the shoot causing NO emission from aboveground plant organs. Nitric oxide (NO) is involved in the response of plants to various forms of stress including hypoxia. It also seems to play an important role in stomatal closure during stress exposure. In this study, we investigated the formation of NO in roots of intact poplar (Populus x canescens) plants in response to hypoxia, as well as its dependence on nitrate availability. We further addressed the question if root hypoxia triggers NO emission from aboveground plant parts, i.e., stems and leaves of young poplar trees. Our results indicate that NO is formed in poplar roots in response to hypoxia and that this production depends on the availability of nitrate and its conversion product nitrite. As long as nitrate was available in the nutrient solution, NO emission of roots occurred in the range of the nitrate concentrations (10--100 A[micro]M) tested, NO emission was widely independent on nitrate concentration. However, the time period in which NO was emitted and the total amount of NO emitted strongly depended on the nitrate concentration of the solution. Hypoxia also led to increased NO emissions from the leaves and stems of the trees. There was a tight correlation between leaf and stem NO emission of hypoxia-treated plants. We propose that NO is produced by nitrate reductase in the roots and either NO itself, a metabolic NO precursor, or a NO derivative is transported in the xylem sap of the trees from the roots to the shoot thereby mediating NO emission from aboveground parts of the plant. Author Affiliation: (1) Institut fur Forstwissenschaften, Albert-Ludwigs-Universitat Freiburg, Georges-Kohler-Allee Geb. 053/054, 79110, Freiburg, Germany (2) King Saud University, Riyadh, Saudi Arabia Article History: Registration Date: 31/10/2014 Received Date: 23/07/2014 Accepted Date: 28/10/2014 Online Date: 15/11/2014
    Keywords: Nitrate ; Nitrate reductase ; Nitric oxide emission ; Oxygen deficiency ; Root-to-shoot transport
    ISSN: 0032-0935
    E-ISSN: 1432-2048
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  • 6
    Language: English
    In: Plant and Soil, 1999, Vol.215(2), pp.115-122
    Description: Sulfur nutrition of plants is largely determined by sulfate uptake of the roots, the allocation of sulfate to the sites of sulfate reduction and assimilation, the reduction of sulfate to sulfide and its assimilation into reduced sulfur-containing amino acids and peptides, and the allocation of reduced sulfur to growing tissues that are unable to fulfill their own demand for reduced sulfur in growth and development. Association of the roots of pedunculate oak (Quercus robur L.) and beech (Fagus sylvatica L.) trees with ectomycorrhizal fungi seems to interact with these processes of sulfur nutrition in different ways, but the result of these interactions is dependent on both the plant and the fungal partners. Mycorrhizal colonisation of the roots can alter the response of sulfate uptake to sulfate availability in the soil and enhances xylem loading and, hence, xylem transport of sulfate to the leaves. As a consequence, sulfate reduction in the leaves may increase. Simultaneously, sulfate reduction in the roots seems to be stimulated by ectomycorrhizal association. Increased sulfate reduction in the leaves of mycorrhizal trees can result in enhanced phloem transport of reduced sulfur from the leaves to the roots. Different from herbaceous plants, enhanced phloem allocation of reduced sulfur does not negatively affect sulfate uptake by the roots of trees. These interactions between mycorrhizal association and the processes involved in sulfur nutrition are required to provide sufficient amounts of reduced sulfur for increased protein synthesis that is used for the enhanced growth of trees frequently observed in response to ectomycorrhizal association.
    Keywords: allocation ; beech ; cysteine ; Fagus sylvatica ; glutathione ; Laccaria laccata ; methionine ; mycorrhization ; oak ; phloem ; Quercus robur ; sulfate ; sulfur ; uptake ; xylem ; xylem loading
    ISSN: 0032-079X
    E-ISSN: 1573-5036
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  • 7
    Language: English
    In: Photosynthesis Research, 2016, Vol.129(1), pp.43-58
    Description: Steady-state rates of leaf CO 2 assimilation ( A ) in response to incubation temperature ( T ) are often symmetrical around an optimum temperature. A / T curves of C 3 plants can thus be fitted to a modified Arrhenius equation, where the activation energy of A close to a low reference temperature is strongly correlated with the dynamic change of activation energy to increasing incubation temperature. We tested how [CO 2 ] 〈 current atmospheric levels and saturating light, or [CO 2 ] at 800 µmol mol −1 and variable light affect parameters that describe A / T curves, and how these parameters are related to known properties of temperature-dependent thylakoid electron transport. Variation of light intensity and substomatal [CO 2 ] had no influence on the symmetry of A / T curves, but significantly affected their breadth. Thermodynamic and kinetic (physiological) factors responsible for (i) the curvature in Arrhenius plots and (ii) the correlation between parameters of a modified Arrhenius equation are discussed. We argue that the shape of A / T curves cannot satisfactorily be explained via classical concepts assuming temperature-dependent shifts between rate-limiting processes. Instead the present results indicate that any given A / T curve appears to reflect a distinct flux mode, set by the balance between linear and cyclic electron transport, and emerging from the anabolic demand for ATP relative to that for NADPH.
    Keywords: Temperature response ; Non-linear Arrhenius plot ; Cyclic electron flow ; Photorespiration
    ISSN: 0166-8595
    E-ISSN: 1573-5079
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  • 8
    Language: English
    In: Trees, 2014, Vol.28(2), pp.399-411
    Description: Byline: Dorte Randewig (1), Domenica Hamisch (2), Monika Eiblmeier (1), Christian Boedecker (2), Jurgen Kreuzwieser (1), Ralf R. Mendel (2), Robert Hansch (2), Cornelia Herschbach (1), Heinz Rennenberg (1,3) Keywords: APR, Adenosine 5 -phosphosulfate reductase; Gas exchange; GSH, Glutathione; Sulfate; SO, Sulfite oxidase; Sulfur dioxide Abstract: Key Message The critical level for SO .sub.2 susceptibility of Populus x canescens is approximately 1.2 uL L .sup.-1 SO .sub.2 . Both sulfite oxidation and sulfite reduction and assimilation contribute to SO .sub.2 detoxification. Abstract In the present study, uptake, susceptibility and metabolism of SO.sub.2 were analyzed in the deciduous tree species poplar (Populus x canescens). A particular focus was on the significance of sulfite oxidase (SO) for sulfite detoxification, as SO has been characterized as a safety valve for SO.sub.2 detoxification in herbaceous plants. For this purpose, poplar plants were exposed to different levels of SO.sub.2 (0.65, 0.8, 1.0, 1.2 uL L.sup.-1) and were characterized by visible injuries and at the physiological level. Gas exchange parameters (stomatal conductance for water vapor, CO.sub.2 assimilation, SO.sub.2 uptake) of the shoots were compared with metabolite levels (sulfate, thiols) and enzyme activities [SO, adenosine 5 -phosphosulfate reductase (APR)] in expanding leaves (80--90 % expanded). The critical dosage of SO.sub.2 that confers injury to the leaves was 1.2 uL L.sup.-1 SO.sub.2. The observed increase in sulfur containing compounds (sulfate and thiols) in the expanding leaves strongly correlated with total SO.sub.2 uptake of the plant shoot, whereas SO.sub.2 uptake rate was strongly correlated with stomatal conductance for water vapor. Furthermore, exposure to high concentration of SO.sub.2 revealed channeling of sulfite through assimilatory sulfate reduction that contributes in addition to SO-mediated sulfite oxidation to sulfite detoxification in expanding leaves of this woody plant species. Author Affiliation: (1) Fakultat fur Umwelt und Naturliche Ressourcen (UNR), Institut fur Forstwissenschaften, Professur fur Baumphysiologie, Albert-Ludwigs-Universitat Freiburg, Georges-Kohler Allee 53/54, 79085, Freiburg, Germany (2) Institut fur Pflanzenbiologie, Technische Universitat Braunschweig, Humboldtstrasse 1, 38106, Braunschweig, Germany (3) King Saud University, PO Box 2454, Riyadh, 11451, Saudi Arabia Article History: Registration Date: 08/11/2013 Received Date: 23/10/2013 Accepted Date: 08/11/2013 Online Date: 27/12/2013 Article note: Communicated by W. Bilger. Electronic supplementary material The online version of this article (doi: 10.1007/s00468-013-0958-x) contains supplementary material, which is available to authorized users.
    Keywords: APR, Adenosine 5′-phosphosulfate reductase ; Gas exchange ; GSH, Glutathione ; Sulfate ; SO, Sulfite oxidase ; Sulfur dioxide
    ISSN: 0931-1890
    E-ISSN: 1432-2285
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  • 9
    Language: English
    In: Plant and Soil, 2017, Vol.418(1), pp.89-114
    Description: Background For 15+ years, a beech (Fagus sylvatica L.) dominated forest on calcareous soil was studied on two opposing slopes with contrasting microclimate in Tuttlingen, Swabian Alb, Germany. The cool-humid NE aspect of these slopes represents the majority of beech forests under current climate, the warmer and drier SW aspect represents beech forests under future climate conditions. The field studies were supplemented by investigations under controlled conditions. Scope The research program aimed to provide a comprehensive understanding of plant-soil-microbe water, carbon and nitrogen feedbacks in a changing climate and a holistic view of the sensitivity of beech to climate change. Conclusions The results of comparative and experimental studies underpin the high vulnerability of adult beech and its natural regeneration on calcareous soil to both direct climate change effects on plant physiology and indirect effects mediated by soil biogeochemical cycles. Mechanisms contributing to this vulnerability at the ecosystem and organismic level indicate a high significance of competitive interactions of beech with other vegetation components and soil microbial communities. Obvious forest management practices such as selective felling did not necessarily counteract negative effects of climate change.
    Keywords: Climate extremes ; Competition ; Forest management strategies ; Girdling ; Rhizodeposition and mycorrhiza ; Thinning
    ISSN: 0032-079X
    E-ISSN: 1573-5036
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  • 10
    Language: English
    In: Plant Molecular Biology, 2010, Vol.72(4), pp.499-517
    Description: The storage and mobilization of nutrients in wood and bark tissues is a typical feature of trees. Sulfur can be stored as sulfate, which is transported from source to sink tissues through the phloem. In the present study two transcripts encoding sulfate transporters ( SULTR ) were identified in the phloem of grey poplar ( Populus tremula  ×  P. alba ). Their cell-specific expression was analyzed throughout poplar in source tissues, such as mature leaves, and in sink tissues, such as the wood and bark of the stem, roots and the shoot apex. Pta SULTR1;1 mRNA was detected in companion cells of the transport phloem, in the phloem of high-order leaf veins and in fine roots. Pta SULTR3;3a mRNA was found exclusively in the transport phloem and here in both, companion cells and sieve elements. Both sulfate transporter transcripts were located in xylem parenchyma cells indicating a role for PtaSULTR1;1 and PtaSULTR3;3a in xylem unloading. Changes in mRNA abundance of these and of the sulfate transporters Pta SULTR4;1 and Pta SULTR4;2 were analyzed over an entire growing season. The expression of Pta SULTR3;3a and of the putative vacuolar efflux transporter Pta SULTR4;2 correlated negatively with the sulfate content in the bark. Furthermore, the expression pattern of both Pta SULTR3;3a and Pta SULTR4;2 correlated significantly with temperature and day length. Thus both SULTRs seem to be involved in mobilization of sulfate during spring: Pta SULTR4;2 mediating efflux from the vacuole and Pta SULTR3;3a mediating loading into the transport phloem. In contrast, the abundance of Pta SULTR1;1 and Pta SULTR4;1 transcripts was not affected by environmental changes throughout the whole season. The transcript abundance of all tested sulfate transporters in leaves was independent of weather conditions. However, Pta SULTR1;1 abundance correlated negatively with sulfate content in leaves, supporting its function in phloem loading. Taken together, these findings indicate a transcriptional regulation of sulfate distribution in poplar trees.
    Keywords: Sulfate transporter ; Phloem loading ; Poplar ; In situ gene expression ; Microautoradiographics ; Seasonal changes ; Real-time RT-PCR
    ISSN: 0167-4412
    E-ISSN: 1573-5028
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