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Forests affect the water balance and thus deep seepage rates differently depending on species composition. Here, the effect of forest conversion on deep seepage rates is investigated in pure and mixed forests of pine (Pinus sylvestris), beech (Fagus sylvatica) and Douglas fir (Pseudotsuga menziesii) at three groundwater-distant and sandy forest sites in Northwest Germany. Based on continuous meteorological, stand precipitation and soil moisture measurements between January 2019 and October 2020, deep seepage rates are modelled with the hydrological model LWF-Brook90. Compared to pure pine forests, modelled deep seepage rates do not increase in mixed forests, but strongly increase in pure beech forests. The results further indicate that tree thinning increases deep seepage rates significantly. These modelled deep seepage rates serve as a basis for an economic evaluation of groundwater recharge as an ecosystem service to promote groundwater-emphasized forest conversion.

Mit der Globalisierung geht auch die Verbreitung von gebietsfremden Arten einher. Bis zum Jahr 2050 wird mit einer Zunahme von bis zu 50 % gegenüber dem heutigen Niveau gerechnet. Diese zukünftigen und die aktuell vorhanden gebietsfremden Arten stellen eine potenzielle Bedrohung für die einheimische Biodiversität dar. In dieser Studie wurden die Verbreitung, die Vergesellschaftung und die Standortbedingungen der invasiven Arten Crassula helmsii (Nadelkraut) und Campylopus introflexus (Kaktusmoos) sowie der potenziell invasiven Art Senecio inaequidens (Schmalblättriges Greiskraut) auf den Ostfriesischen Inseln untersucht und mit früheren Kartierarbeiten verglichen. Mittels der aufgestellten Habitatmodelle war es möglich, die zukünftige Entwicklung dieser Arten aufzuzeigen. Weiterhin wurden der Status Quo der neophytischen Arten auf den Inseln Wangerooge und Mellum sowie dem angrenzten Festland erfasst, um frühzeitig neue Problemarten zu identifizieren.

SERRATE, a multifunctional protein is involved in transcriptional regulation speculatively via transcription factor binding. This study aims at investigating the multiple interacting partners of SE mainly focusing on transcription factors (TF). Y2H library screening and IP-MS revealed 63 TF binding to SE. Confirmatory experiments showed direct interaction of 7 ALFIN1-LIKE proteins, TOE1, TOE2 and IAA34 TF. Co-IP experiments demonstrated that SE binds to AL4, AL5, AL7, TOE1 and IAA34 in planta. al4 al5 al6 al7 mutant was generated via CRISPR-Cas9 to study functional role of SE with TF, which revealed redundancies among alfins. On other hand, se1 toe1 toe2 mutant showed pleiotropic defects though it exhibited no difference in flowering time compared to toe1/2. This indicates TOEs are epistatic to SE. Expression profiles of MIRNAs, their targets and RNA seq analysis of se-1 and toe1/2 showed a speculative role in flowering inhibition during juvenile phase.

Die Auswirkungen der zunehmenden Bodenversiegelung durch Schottergärten führt zu massiven Belastungen des Bodens. Um die Funktionen des Bodens zu erhalten, besteht Handlungsbedarf. Dabei ist die Verbreitung der bodenversiegelten Vorgärten ebenso zu beachten, wie die Beeinträchtigungen der Bodenfunktion und die daraus resultierenden Einflüsse für das Ökosystem. In diesem Zusammenhang werden in dieser Ausarbeitung die Bodenfunktion definiert, sowie diverse Einflussfaktoren dargelegt. Außerdem wird die Verbreitung von Schottergärten und anderen Gärten, die eine Bodenversiegelung darstellen, mit der Hilfe einer Geländekartierung untersucht. Schottergärten beeinflussen die Bodenfunktionen hinsichtlich des Lebensraumes für Flora und Fauna, des Wasserhaushalts, des Gasaustausches, der Bodenfruchtbarkeit und der Wiederherstellung der Ausgangszustandes. In den drei untersuchten Ortsteilen bestehen 10% der untersuchten Gärten aus Schotterflächen und 6,35% stellen eine Bodenversiegelung dar. Um die Bodenfunktion nachhaltig zu erhalten, muss die Verbreitung von bodenversiegelnden Gärten zukünftig gestoppt werden, da aktuell schon eine starke Verbreitung von Schottergärten vorliegt.

In der konventionellen Landwirtschaft spielen Herbizide eine wichtige Rolle. Ihre Wirksamkeit nimmt jedoch durch vermehrtes Auftreten von Toleranzen der Unkräuter ab. Die vorliegende Arbeit leistet einen Beitrag zur Suche nach neuen Wirkstoffzielen für Herbizide. Hierbei wurden zwei Themenfelder behandelt, zum einen das Enzym DHNS des Synthesewegs von Phylloquinon, zum anderen der Vorgang des Spleißens. Für den Schwerpunkt „Validierung von DHNS als Wirkstoffziel“ konnte eine Wirkstoff Wirkort Beziehung aufgezeigt werden, sowie mittels Ergebnissen aus in-vivo und in-vitro Studie die Auswirkungen auf den Organismus illustriert werden. Die Ergebnisse dieses Themenschwerpunkts zeigen die Eignung dieses Wirkziels für die unmittelbare Suche nach neuen herbiziden Molekülen. Die Inhibition des Spleißens konnte ebenfalls erreicht werden, jedoch weist dieser Ansatz ein großes Potenzial für toxikologische Probleme auf. Zur Vermeidung dieser Problematik ist weitere Grundlagenforschung nötig.

Yams (Dioscorea spp.) are important and economical food for millions of people in the tropics and subtropics. However, its cultivation is jeopardized by the post-harvest hardening (PHH) phenomenon characterized by the inability of tubers to soften during cooking. The main objective of this thesis was to provide the basis of genetic breeding for avoidance of the PHH in D. dumetorum. Firstly, using genotyping-by-sequencing, we showed that D. duemtorum accessions in Cameroon are diverse. Secondly, based on long reads sequencing technologies, we released the first and highly contiguity D. dumetorum genome sequence. Finally, harnessing the D. dumetorum genome sequencing and using transcriptome analysis, we demonstrated that genes are differential and up regulated after harvest. The significance of this study is that it defines the framework for the improvement of PHH avoidance and for other significant characters in yam as well as for yam conservation.

Background Yams (Dioscorea spp.) are economically important food for millions of people in the humid and sub-humid tropics. Dioscorea dumetorum (Kunth) is the most nutritious among the eight-yam species, commonly grown and consumed in West and Central Africa. Despite these qualities, the storage ability of D. dumetorum is restricted by severe postharvest hardening of the tubers that can be addressed through concerted breeding efforts. The first step of any breeding program is bound to the study of genetic diversity. In this study, we used the Genotyping-By-Sequencing of Single Nucleotide Polymorphism (GBS-SNP) to investigate the genetic diversity and population structure of 44 accessions of D. dumetorum in Cameroon. Ploidy was inferred using flow cytometry and gbs2ploidy. Results We obtained on average 6371 loci having at least information for 75% accessions. Based on 6457 unlinked SNPs, our results demonstrate that D. dumetorum is structured into four populations. We clearly identified, a western/north-western, a western, and south-western populations, suggesting that altitude and farmers-consumers preference are the decisive factors for differential adaptation and separation of these populations. Bayesian and neighbor-joining clustering detected the highest genetic variability in D. dumetorum accessions from the south-western region. This variation is likely due to larger breeding efforts in the region as shown by gene flow between D. dumetorum accessions from the south-western region inferred by maximum likelihood. Ploidy analysis revealed diploid and triploid levels in D. dumetorum accessions with mostly diploid accessions (77%). Male and female accessions were mostly triploid (75%) and diploid (69%), respectively. The 1C genome size values of D. dumetorum accessions were on average 0.333 ± 0.009 pg and 0.519 ± 0.004 pg for diploids and triploids, respectively. Conclusions Germplasm characterization, population structure and ploidy are an essential basic information in a breeding program as well as for conservation of intraspecific diversity. Thus, results obtained in this study provide valuable information for the improvement and conservation of D. dumetorum. Moreover, GBS appears as an efficient powerful tool to detect intraspecific variation. Electronic supplementary material The online version of this article (10.1186/s12870-018-1593-x) contains supplementary material, which is available to authorized users.

Relational values are values of desirable relationships between people and nature and amongpeople (through nature). We report on the approach to capture relational values of nature’scontributions to people in the regional assessment for Europe and Central Asia of theIntergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES).We present a framework considering indicators along four relational value dimensions aboutpeople’s relationships with nature: security and sovereignty; health; equity and justice; andheritage, social identity and stewardship. The framework has been operationalized for threenature’s contributions to people (NCP): regulation of freshwater quality and quantity, foodand feed, and physical and psychological experiences derived from nature. We identify waysto empirically assess relational values of nature’s contributions to people at regional andcontinental scales with social-ecological indicators and proxies, ranging from biophysicalindicators to indicators that intersect socio-economic with biophysical data. We concludethat many of the identified indicators can be considered as useful proxies of relational valuesin a quantitative way. The analysis shows that relational values are essential to consider at thescience-policy interface as they are an important set of values that people hold about natureand that go beyond instrumental relations.

Genome size is known to vary widely across plants. Yet, the evolutionary drivers and consequences of genome size variation across organisms are far from understood. We investigated genome size variation and evolution in two major subfamilies of the Neotropical family Bromeliaceae by determining new genome size values for 83 species, testing phylogenetic signal in genome size variation, and assessing the fit to different evolutionary models. For a subset of epiphytic bromeliad species, we also evaluated the relationship of genome size with thermal traits and relative growth rate (RGR), respectively. Genome size variation in Bromelioideae appears to be evolutionary conserved, while genome size among Tillandsioideae varies considerably, not just due to polyploidy but arguably also due to environmental factors. The subfamilies show fundamental differences in genome size and RGR: Bromelioideae have, on average, lower genome sizes than Tillandsioideae and at the same time exhibit higher RGR. We attribute this to different resource use strategies in the subfamilies. Analyses among subfamilies, however, revealed unexpected positive relationships between RGR and genome size, which might be explained by the nutrient regime during cultivation. Future research should test whether there is indeed a trade-off between genome size and growth efficiency as a function of nutrient supply.

Astelia pumila (G.Forst.) Gaudich. (Asteliaceae, Asparagales) is a major element of West Patagonian cushion peat bog vegetation. With the aim to identify appropriate chloroplast markers for the use in a phylogeographic study, the complete chloroplast genomes of five A. pumila accessions from almost the entire geographical range of the species were assembled and screened for variable positions. The chloroplast genome sequence was obtained via a mapping approach, using Eustrephus latifolius (Asparagaceae) as a reference. The chloroplast genome of A. pumila varies in length from 158,215 bp to 158,221 bp, containing a large single copy region of 85,981–85,983 bp, a small single copy region of 18,182–18,186 bp and two inverted repeats of 27,026 bp. Genome annotation predicted a total of 113 genes, including 30 tRNA and four rRNA genes. Sequence comparisons revealed a very low degree of intraspecific genetic variability, as only 37 variable sites (18 indels, 18 single nucleotide polymorphisms, one 3-bp mutation)—most of them autapomorphies—were found among the five assembled chloroplast genomes. A Maximum Likelihood analysis, based on whole chloroplast genome sequences of several Asparagales accessions representing six of the currently recognized 14 families (sensu APG IV), confirmed the phylogenetic position of A. pumila. The chloroplast genome of A. pumila is the first to be reported for a member of the astelioid clade (14 genera with c. 215 species), a basally branching group within Asparagales.

Plant performance is correlated with element concentrations in plant tissue, which may be impacted by adverse chemical soil conditions. Antibiotics of veterinary origin can adversely affect plant performance. They are released to agricultural fields via grazing animals or manure, taken up by plants and may be stored, transformed or sequestered by plant metabolic processes. We studied the potential effects of three antibiotics (penicillin, sulfadiazine, and tetracycline) on plant element contents (macro- and microelements). Plant species included two herb species (Brassica napus and Capsella bursa-pastoris) and two grass species (Triticum aestivum and Apera spica-venti), representing two crop species and two noncrop species commonly found in field margins, respectively. Antibiotic concentrations were chosen as to reflect in vivo situations, that is, relatively low concentrations similar to those detected in soils. In a greenhouse experiment, plants were raised in soil spiked with antibiotics. After harvest, macro- and microelements in plant leaves, stems, and roots were determined (mg/g). Results indicate that antibiotics can affect element contents in plants. Penicillin exerted the greatest effect both on element contents and on scaling relationships of elements between plant organs. Roots responded strongest to antibiotics compared to stems and leaves. We conclude that antibiotics in the soil, even in low concentrations, lead to low-element homeostasis, altering the scaling relationships between roots and other plant organs, which may affect metabolic processes and ultimately the performance of a plant.

Coral reefs are experiencing increasing anthropogenic impacts that result in substantial declines of reef-building corals and a change of community structure towards other benthic invertebrates or macroalgae. Reefs around Zanzibar are exposed to untreated sewage and runoff from the main city Stonetown. At many of these sites, sponge cover has increased over the last years. Sponges are one of the top spatial competitors on reefs worldwide. Their success is, in part, dependent on their strong chemical defenses against predators, microbial attacks and other sessile benthic competitors. This is the first study that investigates the bioactive properties of sponge species in the Western Indian Ocean region. Crude extracts of the ten most dominant sponge species were assessed for their chemical defenses against 35 bacterial strains (nine known as marine pathogens) using disc diffusion assays and general cytotoxic activities were assessed with brine shrimp lethality assays. The three chemically most active sponge species were additionally tested for their allelopathic properties against the scleractinian coral competitor Porites sp.. The antimicrobial assays revealed that all tested sponge extracts had strong antimicrobial properties and that the majority (80%) of the tested sponges were equally defended against pathogenic and environmental bacterial strains. Additionally, seven out of ten sponge species exhibited cytotoxic activities in the brine shrimp assay. Moreover, we could also show that the three most bioactive sponge species were able to decrease the photosynthetic performance of the coral symbionts and thus were likely to impair the coral physiology.

Rivers carry large amounts of dissolved organic matter (DOM) to the oceans thereby connecting terrestrial and marine element cycles. Photo-degradation in conjunction with microbial turnover is considered a major pathway by which terrigenous DOM is decomposed. To reveal globally relevant patterns behind this process, we performed photo-degradation experiments and year-long bio-assays on DOM from ten of the largest world rivers that collectively account for more than one-third of the fresh water discharge to the global ocean. We furthermore tested the hypothesis that the terrigenous component in deep-sea DOM may be far higher than biomarker studies suggest, because of the selective photochemical destruction of characteristic biomolecules from vascular plants. DOM was molecularly characterized by a combination of non-targeted ultrahigh-resolution mass spectrometry and quantitative molecular tracer analyses. We show that the reactivity of DOM is globally related to broad catchment properties. Basins that are dominated by forest and grassland export more photo-degradable DOM than other rivers. Chromophoric compounds are mainly vascular plant-derived polyphenols, and partially carry a pyrogenic signature from vegetation fires. These forest and grassland dominated rivers lost up to 50% of dissolved organic carbon (DOC) during irradiation, and up to 85% of DOC was lost in total if subsequently bio-incubated for 1 year. Basins covered by cropland, on the other hand, export DOM with a higher proportion of photo-resistant and bio-available DOM which is enriched in nitrogen. In these rivers, 30% or less of DOC was photodegraded. Consistent with previous studies, we found that riverine DOM resembled marine DOM in its broad molecular composition after extensive degradation, mainly due to almost complete removal of aromatics. More detailed molecular fingerprinting analysis (based on the relative abundance of >4000 DOM molecular formulas), however, revealed clear differences between degraded riverine and deep-sea DOM (molecular Bray-Curtis dissimilarity of ~50%). None of our experimental treatments enhanced the molecular similarity between the rivers and the deep ocean. We conclude that terrigenous DOM retains a specific molecular signature during photo-degradation on much longer time scales than previously assumed and that substantial, thus far unknown, molecular transformations occur prior to downward convection into the deep oceanic basins. peerReviewed

The present work investigates the responses of plants to abiotic environmental conditions and their effects on ecosystem properties. It builds on the notion of the effect-response framework. Mount Kilimanjaro in Tanzania served as a model system, where plant functional traits of the most abundant and widespread species were collected. The main part of this dissertation consists of three chapters to be published as research articles. The first of the main chapters investigates the niche breadths of plant species along environmental gradients and addresses the question whether plant functional traits can predict corresponding niche optima. The second study deals with the variance of trait values within and between plant communities in relation to environmental conditions. In the third main chapter, it is investigated whether plant functional traits, the abiotic environment, or both combined influence mean animal body mass in taxonomically defined groups or feeding guilds.

The on-going destruction of old-growth forests puts tropical forest species under great pressure because of the resulting loss of habitat. An important biotic component of these forests are vascular epiphytes, which structurally depend on trees. In human-modified landscapes potential hosts may still be present, e.g. in the form of isolated remnant trees, small groups of planted trees, in patches of secondary forests, or in plantations. For this study, we assessed the potential of timber monocultures and secondary forest patches to function as refuges for vascular epiphytes. We studied epiphyte assemblages in teak and pine plantations and secondary forest patches of unknown age along a rainfall gradient (1100 – 4200 mm) at the Pacific coast of western Panama and also in a few oil palm plantations. Invariably, rainfall had the expected positive influence on epiphyte diversity and abundance. Individual-based rarefaction curves showed that species richness was significantly lower in timber and oil palm plantations compared to secondary forest patches, which in turn hosted less species-rich epiphyte assemblages than (cultivated and wild grown) pasture trees from the same study region. Our results suggest that the value of timber and oil palm plantations as refuges for vascular epiphytes in human-modified landscapes is limited. Secondary forest patches were more promising in that regard.

Grünkohl ist besonders im Norden Deutschlands jedem ein Begriff und beliebt als wohlschmeckendes und traditionelles Wintergemüse. Doch Grünkohl ist nicht gleich Grünkohl. Das sollte im Rahmen dieser Arbeit schnell deutlich werden, als 12 kommerziell im Handel erhältliche sowie 12 alte ostfriesische Landsorten dieser zum Gemüsekohl (Brassica oleracea) gehörenden Pflanze untersucht worden sind. Das Augenmerk dieser Arbeit richtet sich auf den Anbau der Pflanzen (Wachstumsgeschwindigkeit und -verhalten), deren Habitus, die Gestaltung der Blätter (Krausigkeit, Farbintensität) und auf die Frage, welche Sorten z. B. besser mit einem trockenen Sommer zurechtkommen oder insgesamt Vorteile im Anbau bieten.