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Found 55 results.

Flowering time, development and yield in oilseed rape (Brassica napus): Sequence diversity in regulatory genes

Flowering time (FTi) genes play a key role as regulators of complex gene expression networks, and the influence of these networks on other complex systems means that FTi gene expression triggers a cascade of regulatory effects with a broad global effect on plant development. Hence, allelic and expression differences in FTi genes can play a central role in phenotypic variation throughput the plant lifecycle. A prime example for this is found in Brassica napus, a phenotypically and genetically diverse species with enormous variation in vernalisation requirement and flowering traits. The species includes oilseed rape (canola), one of the most important oilseed crops worldwide. Previously we have identified QTL clusters related to plant development, seed yield and heterosis in winter oilseed rape that seem to be conserved in diverse genetic backgrounds. We suspect that these QTL are controlled by global regulatory genes that influence numerous traits at different developmental stages. Interestingly, many of the QTL clusters for yield and biomass heterosis appear to correspond to the positions of meta-QTL for FTi in spring-type and/or winter-type B. napus. Based on the hypothesis that diversity in FTi genes has a key influence on plant development and yield, the aim of this study is a detailed analysis of DNA sequence variation in regulatory FTi genes in B. napus, combined with an investigation of associations between FTi gene haplotypes, developmental traits, yield components and seed yield.

Coordination and administration of the priority programme SPP 1315 Biogeochemical Interfaces in Soil, Biotic and abiotic factors that dive the function of microbial communities at biogeochemical interfaces in different soils (BAMISO)

Biogeochemical interfaces shape microbial community function in soil. On the other hand microbial communities influence the properties of biogeochemical interfaces. Despite the importance of this interplay, basic understanding of the role of biogeochemical interfaces for microbial performance is still missing. We postulate that biogeochemical interfaces in soil are important for the formation of functional consortia of microorganisms, which are able to shape their own microenvironment and therefore influence the properties of interfaces in soil. Furthermore biogeochemical interfaces act as genetic memory of soils, as they can store DNA from dead microbes and protect it from degradation. We propose that for the formation of functional biogeochemical interfaces microbial dispersal (e.g. along fungal networks) in response to quality and quantity of bioavailable carbon and/or water availability plays a major role, as the development of functional guilds of microbes requires energy and depends on the redox state of the habitat.To address these questions, hexadecane degradation will be studied in differently developed artificial and natural soils. To answer the question on the role of carbon quantity and quality, experiments will be performed with and without litter material at different water contents of the soil. Experiments will be performed with intact soil columns as well as soil samples where the developed interface structure has been artificially destroyed. Molecular analysis of hexadecane degrading microbial communties will be done in vitro as well as in situ. The corresponding toolbox has been successfully developed in the first phase of the priority program including methods for genome, transcriptome and proteome analysis.

Development of an integrated forest carbon monitoring system with field sampling and remote sensing for tropical forests in Indonesia

Forests play a relevant role in mitigation of climate change. A major issue, however, is the scientifically well founded, transparent and verifyable monitoring of achievements in forest carbon sequestration through reduction of deforestation and forest degradation, and through fostering sustainable forest management. Monitoring is particularly difficult in diverse and inaccessible humid tropical forest areas. The proposed research will contribute to the improvement of forest carbon monitoring under the challenging conditions of humid tropical forests. Sample based field observations and model based biomass predictions will be linked to area-wide satellite remote sensing imagery (RapidEye) and to strip samples of LiDAR imagery. Techniques of linking these data sources will be further developed and analysed with respect to (1) precision of carbon estimation and (2) accuracy of carbon regionalization. The proposed project implies research on methodological improvements of both sample based forest inventories (resampling techniques for biomass, imputation of non-response) and remote sensing application to forest monitoring (regionalization, sample based application of LiDAR data). At the core of this research is the analysis of the error variance components that each data source brings into the system. Such error analysis will allow identifying optimal resource allocation for the efficient improvement of forest carbon monitoring systems.

Late-Glacial and Holocene vegetational stability of southern South America

This project focuses on the long-term stability (or otherwise) of vegetation, based on a series of multi-proxy records in southern South America. We will build a network of sites suitable for high-resolution reconstructions of changes in vegetation since the Last Glacial Maximum, and use these to test a null hypothesis that changes in vegetation over the past 14,000 years are driven by internal dynamics rather than external forcing factors. The extent to which the null hypothesis can be falsified will reveal the degree to which we can expect to be able to predict how vegetation is affected by external events, including future climate change. The southern fringes of the South American landmass provide a rare opportunity to examine the development of moorland vegetation with sparse tree cover in a wet, cool temperate climate of the Southern Hemisphere. We present a record of changes in vegetation over the past 17,000 years, from a lake in extreme southern Chile (Isla Santa Inés, Magallanes region, 53°38.97S; 72°25.24W; Fontana, Bennett 2012: The Holocene), where human influence on vegetation is negligible. The western archipelago of Tierra del Fuego remained treeless for most of the Lateglacial period. Nothofagus may have survived the last glacial maximum at the eastern edge of the Magellan glaciers from where it spread southwestwards and established in the region at around 10,500 cal. yr BP. Nothofagus antarctica was likely the earlier colonizing tree in the western islands, followed shortly after by Nothofagus betuloides. At 9000 cal. yr BP moorland communities expanded at the expense of Nothofagus woodland. Simultaneously, Nothofagus species shifted to dominance of the evergreen Nothofagus betuloides and the Magellanic rain forest established in the region. Rapid and drastic vegetation changes occurred at 5200 cal. yr BP, after the Mt Burney MB2 eruption, including the expansion and establishment of Pilgerodendron uviferum and the development of mixed Nothofagus-Pilgerodendron-Drimys woodland. Scattered populations of Nothofagus, as they occur today in westernmost Tierra del Fuego may be a good analogue for Nothofagus populations during the Lateglacial in eastern sites. Climate, dispersal barriers and/or fire disturbance may have played a role controlling the postglacial spread of Nothofagus. Climate change during the Lateglacial and early Holocene was a prerequisite for the expansion of Nothofagus populations and may have controlled it at many sites in Tierra del Fuego. The delayed arrival at the site, with respect to the Holocene warming, may be due to dispersal barriers and/or fire disturbance at eastern sites, reducing the size of the source populations. The retreat of Nothofagus woodland after 9000 cal. yr BP may be due to competitive interactions with bog communities. Volcanic disturbance had a positive influence on the expansion of Pilgerodendron uviferum and facilitated the development of mixed Nothofagus-Pilgerodendron-Drimys woodland.

Omongwa Pan, Namibia (June 2015) - an EnMAP Preparatory Flight Campaign

The dataset is composed of Neo HySpex (VNIR/SWIR) hyperspectral imagery acquired during airplane overflights on June 6th, 2015 covering the Omongwa Pan located in the South-West Kalahari, Namibia. The dataset includes three cloud-free flight lines with 408 spectral bands ranging from VNIR to SWIR wavelength regions (0.4-2.5 µm). The dataset also includes Level 2A EnMAP-like imagery simulated using the end-to-end Simulation tool (EeteS). The overall goal of the campaign was to acquire imagery over the Omongwa Pan and use the spectral reflectance for the analyses of surface sediments, specifically the mineralogical composition of exposed surface evaporites / salts on the airborne and spaceborne scale. The data are highly novel and can be used to test estimation of surface sediment properties in a highly saline and dynamic environment.

Light in - Light out

Mankind is approaching a crisis in energy generation and utilization. Traditional fossil fuel reserves are diminishing and legislative issues regarding CO2 emission will make use of existing lower grade reserves unattractive. New technologies have to be developed to satisfy the ever-increasing energy demand and to maximize efficient energy usage. The materials chemist, through the design of new materials with novel properties and by controlling interfacial interactions between materials, will play a crucial role in these endeavours and in enabling the paradigm shift that is required. This project is centred around two core and inter-related issues (i) energy generation from photovoltaics using sunlight and (ii) efficient lighting devices based on light-emitting electrochemical cells (LECs) and organic light emitting diodes (OLEDs). Both of these topics are areas of intense activity world-wide. Within Europe the PIs research group is one of the leaders in the field. However, as research efforts in these areas are proving successful and proof-ofprinciple systems are being established and optimized, a new factor needs to be addressed. State of the art photovoltaic devices based upon the dye-sensitized solar cell (DSC) most frequently utilize inorganic dyes comprising ruthenium complexes of oligopyridine ligands. The projected next generation mass market OLEDs and prototype LECs are based upon iridium complexes containing cyclometallated pyridine ligands. A traditional criticism of these approaches related to the costs of the raw materials although this is in reality low compared to the costs of other components. However, the price reflects in part the availability of these metals and in this respect devices based upon ruthenium (1 ppb by atom in Earth crust) or iridium (0.05 ppb by atom in Earth crust) are unsustainable. This project is concerned with the development of complexes based upon abundant and sustainable first row transition metals to replace second and third row transition metals in these devices. Initial efforts will centre upon complexes of copper(I) and zinc(II) which have well-established photochemistry and photophysics making them suitable for such applications. The PI has already established proof-of-principle for the replacement of ruthenium by copper in DSCs and is a world leader in this technology. The work on the two projects will involve (i) materials synthesis and characterization (ii) computational modelling (iii) device construction and testing and (iv) property optimization.

WTZ Südliches Afrika SPACES: GeoArchives II - Signale des Klima- und Landschaftswandels konserviert in Geoarchives des südlichen Afrika, Vorhaben: Hänge, Schwemmfächer und Flussterrassen als Geoarchive; Rekonstruktion der Paläoumwelt- und Paläoklimasignale (SP2; SP4)

1. Vorhabenziel: Die Untersuchung von mikrobiellen Gemeinschaften in Salzpfannen im südwestlichen Afrika über die Zeit birgt das Potential, wertvolle Informationen über die mit den Mikroorganismen assoziierten Klima- und Umweltbedingungen der Vergangenheit zu erhalten. In der GeoArchives II Phase wollen wir neue mikrobiologische Ansätze und Methoden anwenden, um die Änderungen der mikrobiellen Gemeinschaften mit der Zeit zu dokumentieren (Kultivierungsexperimente von Schlüsselorganismen, externe DNA als Schlüssel zur Vergangenheit), die gewonnenen Daten mit biogeochemischen Methoden (mikrobielle Biomarker) zu validieren und Klimainformationen aus den Daten abzuleiten. Außerdem wollen wir die Wechselwirkung von Mikroorganismen mit Gesteinsoberflächen im Zuge von bodenbildenden Verwitterungsprozessen in der Region untersuchen. Weiterhin sollen mit Hilfe geochronologischer Datierungsansätze relevante Landschaftsformen (Salzpfannen, Hänge, Schwemmfächer und Terrassen) in ihrer Genese datiert werden, um aktuelle Fragen nach den Auswirkungen des Klima- und Nutzungswandels auf die heutigen Landschaftsökosysteme zu beantworten. 2. Arbeitsplanung: Im Projekt sollen zwei Probenahmen durchgeführt werden. Die Salzpfannen werden Ende 2016 Gegenstand der ersten Kampagne sein. Die Salzpfannenproben sollen für die Kultivierungsexperimente und die Studien zur extrazellularen DNA verwendet werden. In der zweiten Kampagne soll im Frühjahr 2017 im Tsauchab-Tal Material für die Untersuchung der Verwitterungsprozesse gewonnen werden. Des Weiteren sollen Altersdatierung von Hangsedimenten, Schwemmfächern, Flussterrassen und Talbodenverschüttungen vorgenommen werden, um die Stabilität und das Potenzial dieser Flächen für die Landnutzung unter dem Einfluss des Klimawandels zu bewerten.

WTZ Südliches Afrika SPACES: GeoArchives II - Signale des Klima- und Landschaftswandels konserviert in Geoarchives des südlichen Afrika, Vorhaben: Molekulare Paläoklimatologie

WTZ Südliches Afrika SPACES: GeoArchives II - Signale des Klima- und Landschaftswandels konserviert in Geoarchives des südlichen Afrika, Vorhaben: Rekonstruktion holozäner Umwelt- und Klimaschwankungen

Energy and Water Fluxes at the Soil Atmosphere Interface of Water Repellent soils

Water repellency (WR) plays a significant role in a large number of soils all over the world. In many regions global warming will lead to drier land surfaces and thus, increasing the likeliness of actual water repellency for such soils. The hydrological effects of WR (surface runoff, water erosion, preferential flow) have been relatively well investigated in the last decades. However, its effect on the energy balance between soil and atmosphere has not been studied yet. We postulate that global warming does not only lead to an increase in WR of soils, but WR has an impact on the energy balance and thus, will lead to a feedback on global warming. In order to test our hypothesis, we want to determine all components of the energy- and water balance between soil and atmosphere for a strongly water repellent soil. As a reference we want to repeat the same measurements for the same soil, at which the WR has been suspended by application of a surfactants. While the laboratory studies aim to give insight into more principle processes, the lysimeter (bare and with plants) and field scale studies shall give information about integrated complex natural processes. The gained knowledge shall be implemented into a numerical simulation tool for modeling water and energy balances in order to predict the effects of WR under different atmospheric conditions and physical soil properties.

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