Plants have (re)adapted independently to saline sites several times. We have begun to construct phylogenetic trees for several salt marsh species to determine their closest relatives and to determine intraspecific variation. In the process, we have repeatedly noticed that species within the salt marshes are variable, in particular possessing different numbers of chromosome sets (polyploidy). The aim of this project is to create a phylogenetic tree for further species of the North German salt marshes (from the genera Triglochin maritimum, Elymus spec., Silene flos-cocculli, Lotus corniculatus/L.tenuis, Potentilla anserina, Centaurium spp., Tripleurospermum maritimum/T. inodorum) and to use it for the analysis of different questions of evolution. Where do the northern German salt marsh species come from? Are the closest relatives also already adapted to salt? What characteristics do the salt marsh species have in common that they did not get from their ancestors? These questions will be investigated using a variety of different methods.

Methods: Flow cytometry, microscopy (root anatomy), computer based phylogenetic and comparative analyses.

Flavonoids are a widely distributed class of compounds in the genus Veronica. In the last 50 years a number of species have been studied, so it is known that mainly flavones such as luteoline and apigenine occur, which are related to oxidative stress but also antibacterial activity of plants. In addition, anthocyanins are present, especially delphinides but also cyanides, which are responsible for the blue to red coloration of flowers. Comparison of the data with phylogenetic analyses of recent years has shown that there are some substances that are characteristic of certain groups within the genus Veronica. For example, flowers of the subsection Cymbalaria are white, suggesting an absence of anthocyanins. Cyanidins have only been recorded in the New Zealand section Hebe. The subgenus Pseudolysimachium differs from all other subgenera in the production of spicosides, 6-OH-luteolin acylated with phenolic acids such as caffeic acid. Finally, the relationship of the morphologically very different subgenera Pocilla and Pentasepalae was supported by the presence of 8-0H-flavones exclusively in these two subgenera. Genomic and transcriptomic data, now available for many of these groups, may now allow us to find the genetic basis for this variation in flavonoid presence.

Methods: Analysis and comparison of genomic and transcriptomic data.

Veronica subgenus Beccabunga is a group of species that can be found adjacent to or inside bodies of water, like rivers and lakes. Species delimitation is challenging because plants can look very different if they grow in water or on dry soil. Thus, we need a DNA based analysis to disentangle useful characters from those having evolved in parallel or phenotypically plastic ones. We aim to elucidate the phylogenetic relationships in the subgenus, as well as population structure and hybridization patterns by analyzing High-Throughput Sequencing (HTS) data. In addition, we want to review herbarium specimens in order to find morphological characters that may help us in delimiting closely related species.

Methods: DNA extraction, Nanopore sequencing, genotyping-by-sequencing, bioinformatics analysis methods, microscopy

n a previous master's thesis, we found that Veronica spicata and V. longifolia often form hybrids with each other, and we also performed this hybridization with different origins in the greenhouse. The hybrids have now germinated and grown. This raises the question of how the hybrid differs in relation to the parents. For this purpose, DNA sequencing should first be used to prove that they are hybrids. After that, morphologically the hybrid should be described in relation to the parents. Since the parents differ very much in location, V. longifolia is in marshy meadows, V. spicata in dry grasslands, it should be investigated how well the hybrid tolerates drought.

Methods: DNA sequencing, morphological description, greenhouse experiment.

Many species of Veronica are self-incompatible, i.e. there are gene products that allow plants to recognize pollen from their own plant (gametophytic self-incompatibility). Recent molecular biology methods, especially transcriptomics/RNA sequencing, now allow to identify the corresponding genes. Within the Plantaginaceae this has so far only been done for Antirrhinum. In this project, the aim is to sequence RNA from the pistil for V. filiformis, V. spicata and V. chamaedrys and to identify the corresponding homologous genes for Veronica.

Methods: RNA sequencing

The systematics of the genus Veronica has long been a focus of the working group. There are still a number of species groups that are insufficiently known and where there may still be new species to discover. These species groups include the Veronica petraea group from the Caucasus, the Siberian Veronica pinnata group, the aquatic Veronica anagallis-aquatica species or the Veronica orientalis relatives from the Middle East. For all working groups there is plant material in the herbarium that can be analysed for morphology and from which DNA can be sequenced.

Methods: Morphometry, DNA sequencing

The genus Tragopogon (Asteraceae) is widespread in Europe in meadows and partly also in ruderal areas. Analyses of DNA sequence data have shown that the widespread species T. pratensis and T. dubius actually consist of several genetically separate lineages. The aim of this project is to find out to which of these lineages the plants in the herbarium of the University of Oldenburg belong. DNA sequencing and morphological studies will be used to characterise the diversity and find out more about the distribution of these genetic lineages.

Methods: DNA sequencing, morphological studies

Central Europe has virtually no new plant species of its own, because almost all species had to migrate post-glacial. An exception is the small scabious, which presumably forms an own, purely Central European species as a post-glacial hybrid. Resynthesis from the presumed parents will be attempted with crossing experiments. Experiments on the germination behavior of the seeds in climate chambers and in the field will shed light on possible reasons for the success of the new species. Furthermore, a molecular marker will be established that could provide information on the place of origin and migration history in future analyses. Create F1 hybrids, survey 3 species (ca. 30 ind.), seed 200, germination behavior qualitative.

Methods: germination experiments, morphological studies, DNA sequencing.

Highly sensitive DNA sequencing methods allow DNA to be extracted from the environment even though the organisms are no longer there or are so small that they cannot be seen. In one project, we tested which insect DNA we can isolate from flowers and whether flower visitors have left their DNA behind. However, we realised that we still need to improve the protocol. In particular, the question of which DNA extraction kit and which primers are suitable requires further work.

Methods: DNA extraction, DNA sequencing

Rhododendron (Ericaceae) is the largest genus of woody plants (about 1200 species), with a complex and highly debated taxonomy. About 98% of the rhododendron’s species are confined to the old world except most of the beautiful Azaleas and few non- Azalean rhododendrons. Among the non-Azalean rhododendrons, Rhododendron subsect. Caroliniana has a very confused taxonomy and interesting ecology with three species. Recently, Bauer and Albach reported a new species, which led to a change in the total number of species in R. subsection Carolianiana from three to four. The newly reported species is from the Great Smoky mountains named as R. smokianum Ralf Bauer & Albach. We are interested to investigate the genetic cohesion/diversity based on the genomic data in this four species complex and whether there may actually even be more unrecognized species in the group.

Methods: GBS, phylogenomic and population genetics.

Cultivated varieties (cultivars) of plants are available in DIY stores, supermarkets and perennial nurseries. They are specifically selected for certain phenotypic characteristics such as abundance of flowers, colour, shape or fragrance, which are particularly aesthetically pleasing to humans. Cultivars are mainly used for urban greening and in private gardens.

However, numerous studies show that native pollinators usually prefer wild plants to cultivars. For this reason, many perennial nurseries offer wild forms alongside cultivars in order to promote near-natural gardens. There is a large variety of cultivars of Achillea millefolium (yarrow) in particular, as well as popular crosses with Achillea filipendulina. Some of these varieties are advertised as "bee-friendly" or "bee pasture" - but the question arises as to whether cultivars are actually as interesting for insects as the wild forms and whether a distinction is made between native and non-native wild forms.

To investigate this, ten areas will be planted with a total of 16 cultivars of Achillea millefolium. These will be compared with a wild form from a local, historical cultivated landscape, a wild form from Sweden and a wild form from each of two regional perennial nurseries. Over the summer, the phenology and morphology of the plants will be recorded and targeted insect observations will be carried out. In addition, the pollen of plants cultivated in a common garden will be analysed.

Methods: Insect observations, stereomicroscopy, pollen counting

Urban gardens are nowadays a significant part of nature and thus of insect habitat. Thus, planted ornamental plants are an important resource for pollen- and nectar-collecting insects. Ornamental plants are selected and bred for attractiveness to humans. However, breeding often results in a decrease in pollen and nectar. However, this has rarely been studied thoroughly. The goal of this project is to investigate this for 1-3 species (e.g. Veronica spicata, Rhododendron spec., Geranium wallichianum). The project involves measuring nectar and pollen levels and observing insects on these plants to investigate the hypothesis that ornamental plants provide fewer resources for insects than native plants.

Methods: Nectar measurement, pollen counting, observation of flower visitors.

Flowers are necessary for sexual reproduction of plants. The longer they are open, the higher the chance of pollination and successful reproduction. However, keeping flowers open also imposes costs on the plant through increased transpiration and water loss. Therefore, there is a high variation in plants in how long flowers are open. Little is known about what influences the flowering length of a single flower. This will be investigated by studying as many species of the genus Veronica as possible. Is there variation among closely related species? Do species with longer open flowers have a higher probability of being pollinated?

Methods: Flower observation, comparative computer analysis in a phylogenetic-comparative framework.

Insects and therefore most pollinators perceive other colors than we do, because their eyes are additionally sensitive for ultraviolet radiation. So it is no wonder that many flowers display UV-signals, that are not visible for us. The shape and look of these signals, their occurrence and distribution among plant families or genera and some other factors are not known very well. The candidate will mainly systematically screen as many flowers in the Botanical Garden as possible for a potential UV-signal.

Method: comparison of self-made normal and UV-photographs.

Project Research into the representation of plants and botanical objects/terms in selected children's and young adult literature (#plantawareness, #plantblindness). How are plants depicted? What characteristics do the plants have? Are depictions and communicated characteristics botanically correct? What values or knowledge are conveyed by the illustrations and texts?

Various aspects can be addressed, e.g. (1) literature in Germany versus abroad; (2) in the past versus today, (3) children's books from the former FRG versus the GDR; (4) ...

For the comparison of German and English-language literature, it is best to have a teaching degree in German/Bio or a very good knowledge of English. In addition, a good knowledge of botany is expected in order to be able to adequately evaluate the literature. A survey or interviews with various actors would be conceivable. An interest in and enjoyment of reading is of course also a prerequisite.

In summer semester 2025, mapping in an Oldenburg allotment garden association will clarify how many and which plant species are present. The inventory will largely be carried out using identification apps. It may be necessary to check these results with specialist literature. The FLORA identification exercises should therefore have been successfully completed. Basic knowledge of native plant families is urgently required. One of the outputs to be developed is information boards for the allotment garden association and visitors. They should not only be attractively designed (photos and/or drawings), but also provide generally understandable information about exciting facets of the work (#funfacts, #neophytes, #insect-friendly planting, #pollination, ...). In addition, a separate zoological work on species recording would be conceivable (#pollinator observation).

The work should develop suitable materials for the "cutting course". These can be hands-on models (e.g. 3D printing, wooden models) or creative instructional videos (papercut video, tutorials, ...). The function and properties of cellulose, hemicellulose and pectin as chemical components of ZW formation should be explained in a technically correct way (#stability, #colouring histology, ...). In addition to the changes/differences in the structure of primary, secondary and tertiary walls, apoplastic water transport and the role of (court) stains should also be considered (#resistance, #stability, ...). Candidates should have completed the course themselves, be creative and have an interest in teaching.

The work is intended to create educational boards (roll-ups) with which the histology of the basic organs can be didactically well prepared and conveyed. The aim is to compare monocotyledonous and dicotyledonous angiosperms (shoot axis), but also to compare shoot axis and roots. In addition, an anonymous online survey of students in the 2nd semester will be used to identify the biggest hurdles ("needs analysis"). A set of histological sections (permanent preparations) should be created that can be used to test learning. This can be done, for example, through a catalogue of questions about the objects or worksheets/assignments. Creative learning aids for self-assessment (memory, flashcards, quizzes, ...) are desirable.

The project aims to develop learning aids to avoid confusion when addressing plant families. Based on the materials already used in the course (PDFs, models, educational boards, real objects, ...), creative learning aids should be developed that emphasise the similarities and differences between native plant families. This should be done as creatively as possible. Whether video clip, zines, quizzes via QR code, self-designed app, roll-up, station learning or a song text/poem. Anything that helps is allowed! It is important that the FLORA identification exercises have been successfully completed.

The orchard meadow in Eversten Holz is to become a local biodiversity hotspot in the future. To this end, the construction of flowering meadows, Benjes hedges (deadwood hedges) and nesting opportunities or insect hotels is planned. The development of an educational concept (guided tour, workshop, educational panel or interactive station with high-quality hands-on objects) will further enhance the area. Visitors should be sensitised on site to the close link between plant and insect diversity (#pollination syndromes, #insect extinction, #biodiversity crisis). Sustainable planting of native species in the orchard area (flowering meadow), which is available as a resource for many pollinators, should be at the centre of the educational concept. It is advantageous to have completed the pollination and dispersal biology course.

The Botanical Garden is one of Oldenburg's most visited attractions with more than 70,000 visitors a year. Visitors not only come there to relax, but also to learn something. This can be done via podcasts, printed guides, guided tours and signs, for example. We want to use newly developed interactive experiments to convey botanical and other biological content to visitors. The design requires a certain didactic interest. Topics could be, for example, the phenology of plants (in connection with climate change), the tropical house, the Alpinum, Australia, plant groups, e.g. the rose family, the history of ornamental plants or the topic of wind pollination. It is also possible to work on a sensible redesign/planting of various beds, such as the creation of a climate change bed or permanent experiments in the new subtropical house. Such a guide or signposting is possible for the bog educational garden at the Elisabethfehn bog museum.

Methods: didactic design, conceptualisation and science communication

Do you think lectures are old-fashioned? You'd rather learn everything in nicely packaged YouTube videos. Maybe you're right. Would you like to pack a 90-minute lecture into several YouTube videos? The lectures of the Flora module are particularly suitable for this, as it would be much nicer to demonstrate all the topics in the Botanical Garden. The work should transfer some topics into 3-5-minute videos. Discuss the possibilities and limitations and compare them with existing YouTube videos.

Methods: Didactic analyses, watching YouTube

The Organismic Biology course takes place on seven course days in the winter semester, usually for first-year students. The aim of this project is to develop offers in the Botanical Garden to deepen and expand the course content in the Botanical Garden. Topics could include making the connection between leaf characteristics and nomenclature.

Methods: Homepage development, didactic design and conception.

The Botanical Garden offers many activities for school classes, but not for sixth form groups. We therefore want to offer curriculum-related programmes for upper school classes in the Botanical Garden. In these final-year courses, offers are to be created that deal with a topic (or two topics combined) within 90 minutes in the Botanical Garden. The following topics are available: Structure of the cell (possibly with fungal cells, osmosis, plasmolysis), photosynthesis (incl. C3, C4, CAM), plant and water (transpiration, xerophytes, stomata), ecosystem and ecological niche (forest, bog), symbiosis and parasitism, climate change/greenhouse effect, genetics (mutation, epigenetics, heredity, possibly plant breeding), selection and gene drift, speciation and species concept. Didactic supervision is provided by teaching staff from outside the university.

Methods: Specialised didactics, microscopy, field experiments, etc.

Many plants are able to form roots on the shoot when the shoot becomes moist. This is thought to be an adaptation of plants in humid areas, which can at least occasionally break off and then form new plants. The genus Veronica is ecologically very variable, i.e. it occurs from aquatic to steppe-like habitats. It is therefore well suited for testing experimentally whether the ability to form adventitious roots really correlates with the habitat. Other aspects include how quickly adventitious roots are formed, where on the shoot and under what humidity.

Methods: Experiments with plants in the greenhouse

Veronica hederifolia and V. sublobata are two closely related species that differ in ploidy (number of chromosome sets), but nevertheless occur directly next to each other also in Oldenburg. In previous studies it was determined which characteristics are suitable to distinguish the species and in which they do not differ. In the case of the characteristics, however, it is not clear what influence the environment has. For example, flowers are different when the plants are next to each other, but are the flowers of V. hederifolia different only in the sun, but also pale in the shade. Or are leaves the same when the species are next to each other in shade, but different in sun.

Methods: Growth experiments in the greenhouse, flow cytometry if necessary.

Polyploid and diploid plants of a species differ in a number of factors because the cell size differs, even if genetically hardly anything changes. In this experiment, the water utilisation efficiency and photosynthetic activity in particular are to be investigated. This will be investigated in diploid and tetraploid individuals of the drought-adapted Veronica spicata and diploid and tetraploid individuals of the moisture-adapted Veronica longifolia and diploid and tetraploid individuals ofSalicornia on the North Sea coast.

Methods: Water use efficiency analysis, photosynthesis measurement, microscopic analyses

Roots are usually overlooked but nevertheless important features that serve to absorb water and nutrients. Accordingly, it is not surprising that they can vary depending on external circumstances such as moisture. These species-specific characteristics depending on humidity and salinity will be analysed here. Plants of the genus Veronica (subg. Chamaedrys, subg. Pseudoveronica) and salt marshes(Festuca, Triglochin, Elymus, Silene, Lotus, Potentilla, Centaurium) from other projects are available for this purpose. An experiment will be carried out in the greenhouse to see whether and how roots change and how this is linked to adaptability to environmental conditions. Of particular interest here is the root quotient (central cylinder/total diameter), root length and total diameter.

Methods: Greenhouse experiment, microscopy

Green roofs are one way of mitigating the effects of climate change in the city, and it is important to know as much as possible about them at a local or regional level. The plant species that thrive on green roofs are particularly important. Starting from the initial planting with a set of typical species, there will soon be changes, because depending on exposure, location and maintenance, some species will be lost and other species will spontaneously appear. There are green roofs in the Botanical Garden and the surrounding area that are suitable for comparison. It may then be possible to make recommendations for the planting of green roofs in Oldenburg.

Methods: Vegetation surveys and measurement of abiotic factors

Due to its chemical and physical properties (water and nutrient absorption and release, air volume, etc.), biochar, produced from plant residues, can be used in a variety of ways in agriculture. One area of application is the use of charcoal in horticulture as a peat substitute. This topic is also one of the contents of the TOPKO project (https://uol.de/topko).

The TOPKO project plans to carry out planting trials with five different test plants on 8 different coal compost substrates during the growing season from the end of April/beginning of May to October 2025 (approx. 1000 test plants in total). The aim is to find out to what extent the coal-based substrates used are suitable as a peat substitute and where there is still a need for optimisation. The activities include planting, watering, general care and observation, assessing and harvesting the plants. In addition, there are substrate analyses (i.e. some laboratory work) and then, of course, the (statistical) evaluation of the data.

The most time-consuming part of the programme is the planting of the trials and harvesting, and then of course the substrate analyses and evaluation, i.e. you can continue to attend lectures while the plants are growing.

If you are interested, just get in touch with me at and we will discuss all further details.

Geometric morphometrics allows the quantitative study of leaf shapes. However, these methods work best with specimens that have been collected and photographed specifically for this purpose, while preparation of data and extraction of leaf outlines from herbarium leaves may require extensive manual processing of photographs. A few pipelines have been proposed to extract leaves from photographs of herbarium leaves using object recognition algorithms. One of these pipelines is ginjinn2. Your task will be to test the usefulness of ginjinn2 for extracting leaf outlines from herbarium leaves of different speedwell species (Veronica, Plantaginaceae) and to analyze the resulting leaf outlines using geometric morphometric methods (Elliptic Fourier Descriptors). In particular, we are looking for differences in leaf shape between populations from different geographical areas.

Methods: Morphological images, computer analyses

In the beautiful and protected genus Gentianella there are various types of conspicuous pharyngeal scales, e.g. some with and some without their own vascular bundle. These scales probably serve as protection against nectar predators and raindrops. It is unclear from which organs these types of scales originate. By tracing these scales during flower formation (ontogenesis), we hope to find clues to their origin. It is therefore necessary to book in advance in order to prepare sufficient fresh material soaked in alcohol.

Methods: Scanning electron microscopy, anatomy

Salt marsh plants are adapted to a location that is extreme for plants. Physiological characteristics are mostly in the foreground. Morphological characteristics are less known. This project will investigate some hypotheses about the difference between salt marsh species and their closest relatives. These include stomatal size and density (see Li & al. 1996; Maherali & al. 2009), epidermis thickness, and xylem cell size and xylem cell wall thickness (see Nassar & al. 2008, Maherali & al. 2009, Hao & al. 2013).

Methods: morphological and anatomical examination on microscope, staining and preparation of microscopic objects, collecting plants in nature, if necessary for M.Sc. thesis analysis of traits in phylogenetic comparative analysis. Experiments can also be carried out in the Botanical Garden to study the phenotypic plasticity of the traits.

The herbarium in Oldenburg contains about 20,000 specimens of dried plants of many different species from many different countries. But what else was actually dried? We are sure that partly plants were dried that contain pathogens or symbionts like fungi or insects. The aim of the project is to search the herbarium and to try to find and identify these "by-catches". Are there specific fungi or insects? The search should begin systematically with a genus of plants.

Methods: microscopy, DNA sequencing

Pollen contains the male gametophyte of flowering plants. There are a number of hypotheses as to what determines their appearance, especially their size. For example, we have found that the pollen of Veronica spicata is smaller in pine forests than in open grassland. The aim of this project is to test these hypotheses for the genus Veronica. To this end, pollen sizes will be collected from the literature and analysed under a light and scanning electron microscope. The following questions will be investigated: Is there a correlation of pollen characteristics with relatedness? Is there a correlation with genome size? Do alpine species have larger pollen than non-alpine species? How do polyploid plants differ from diploid plants of the same species? Can we experimentally influence pollen size?

Methods: light microscopy, scanning electron microscopy, greenhouse experiments, for M.Sc. and possibly bio900 also comparative phylogenetic analyses

Veronica has about 460 species, of which there are currently IUCN assessments for 19 species only, although there are still a number of endemic species that are studied for the country by which they occur (especially New Zealand). However, the lack of endangerment classification prevents effective protection of the species. The project will investigate how well an automated assessment compares to expert knowledge. Based on distribution data from GBIF, inaturalist and targeted additional information (e.g. Herbar Oldenburg), species will be classified into endangerment classes (a priori) using the IUCNN program (Zizka et al. 2022) and deep learning models. The results will be discussed with experts and problems identified. These problems could be taxonomic issues, common confounders, or historical changes in distribution and abundance. The distribution data will then be improved and the analyses performed again, resulting in a second classification (a posteriori).

Methods: distribution range modeling, conservation assessment methods.