Promovendi

Momenteel werken er twee promovendi in de Hortus. Ook van oud-promovendus Marc Appelhans, gepromoveerd in november 2011, zijn de gegevens hieronder opgenomen.

Svenja Meinke (MSc): Evolutionary studies on the liana habit within Annonaceae
Svenja Meinke

Lianas play many important roles in tropical forest ecosystems. Thus, their ecology has been studied extensively. However, very little is known about the evolution of lianas. This PhD-project aims at closing this gap of knowledge.
Annonaceae are an ideal model group for this kind of study. Lianas have evolved several times within the family but still they are restricted to one major clade. This gives an excellent opportunity to investigate the different origins and types of lianas.
For this purpose we are going to use a variety of different approaches. First the molecular phylogeny of this Annonaceae subclade will be resolved to see how often lianas have evolved within the family. In the second step, morphological and anatomical studies on wood and climbing habit will be conducted. This will also give a better answer to the question: “What actually is a liana?” In a third and fourth step biogeographic and palaeoclimatic studies will give evidence about the time and place of the different liana origins and their possible future distribution.

Publications:
Meinke, S., Koenig, N. & Porembski, S. (2007): Preliminary observations on the pollination biology of West African Annonaceae. AETFAT Congress, Yaounde, Cameroon (Poster)

Rachel Schwallier (MSc): Niche differentiation in tropical pitcher plants (Nepenthaceae)
Rachel Schwallier

Nepenthes are carnivorous tropical pitcher plants with limited distribution and specialized diet attracting abilities. Although these plants capture the interests of many scientists, ecological niche differentiation has never been investigated. The aim of this project is to understand the mechanisms and processes that generate diversity in Nepenthes. To do so, niche diversification with emphasis on drought resistance and shade tolerance as the main drivers of resource partitioning during the evolution of Nepenthes will be analyzed using ecological niche models, drought resistance and shade tolerance experiments. Pitcher 3D morphometrics will be compared in species with differing diet specializations and used in conjunction with landmark analysis and field inventories to link hybrid morphologies to maladaptive spaces. In addition to this, critically imperiled species that were put in the care of the Hortus botanicus Leiden through the Ark of Life Project (http://www.arkoflife.net) will be barcoded for wildlife forensics.

Marc Appelhans (MSc) : Phylogeny and biogeography of the Spathelioideae (Rutaceae)
Marc Appelhans

PhD-project
The Spathelioideae are a subfamily of the Rutaceae and comprise seven small genera. According to their strikingly different morphology, these genera used to be placed in various different families before molecular phylogenetic studies on genus level inferred their relationship.
The goal of this PhD project is to develop approaches to tackle the incongruence of the molecular data and the relationships inferred from morphology and anatomy using the Spathelioideae as a prime example. For this purpose, the detailed molecular phylogenetics of this group containing all species will be studied using different DNA markers. A comparative study of several morphological/ anatomical characters and also phytochemical analyses will be carried out and the results will be compared to the molecular data.
Additionally, the age and the origin of this pantropically distributed subfamily will be investigated with an ancestral area reconstruction analysis and a molecular dating analysis using well identified fossils of Rutaceae and Simaroubaceae.

Research interests
Phylogeny, Taxonomy, Anatomy, Biogeography of Angiosperms (especially Rutaceae and related families, Plumbaginaceae, and Melastomataceae).

Projects for MSc and BSc students
Spathelioideae are a very variable group in terms of plant morphology but our results clearly show that they form a monophyletic group within the Rutaceae family. We have already found some anatomical features of leaves and seeds that are in concordance with the molecular results, but comparative studies of several characters have never been studied in this group. Possible projects for MSc or BSc students are comparative studies of wood anatomy and pollen morphology of this group.

Publications

Articles in refereed SCI journals:

Appelhans MS, Smets E, Razafimandimbison SG, Haevermans T, van Marle EJ, Couloux A, Rabarison H, Randrianarivelojosia M, Keßler PJA. 2011. Phylogeny, evolutionary trends, and classification of the Spathelia / Ptaeroxylon clade: morphological and molecular insights. Annals of Botany 107: 1259-1277
Razafimandimbison SG, Appelhans MS, Rabarison H, Haevermans T, Rakotondrafara A, Rakotonandrasana SR, Ratsimbason M, Labat J-N, Keßler PJA, Smets E, Cruaud C, Couloux A, Randrianarivelojosia M. 2010. Implications of a molecular phylogenetic study of the Malagasy genus Cedrelopsis and its relatives (Ptaeroxylaceae). Molecular Phylogenetics and Evolution 57: 258-265.
Appelhans MS, Smets E, Baas P, Keßler PJA. 2010. Cneorum (Rutaceae) in Cuba? The solution to a 150 year old mystery. Taxon 59: 1126-1134.
Appelhans M, Weber HC, Imhof S. 2008. Rutaceae sampled from Germany, Malta, and Mallorca (Spain) are associated with AMF clustering with Glomus hoi Berch & Trappe. Mycorrhiza 18: 263-268.


Contributions to conferences:

Appelhans MS, Janssens SB, Smets E, Keßler PJA. 2011. The Spathelioideae: Molecular phylogeny and historical biogeography of a subfamily of Rutaceae (Sapindales) with remarkable morphological diversity. Biosystematics 2011, Berlin, February 21-27. Oral presentation. [Awarded the student prize for the best oral presentation].
Appelhans MS, Smets E, Keßler PJA. 2010. Molecular phylogeny and historical biogeography of the genus Harrisonia (Rutaceae, Sapindales) and its relatives. 8th International Flora Malesiana Symposium, Singapore, August 23-27. Oral presentation.
Appelhans MS, Smets E, Keßler PJA. 2009. The Spathelia / Ptaeroxylon clade: A subfamily of the Rutaceae or a separate family? SYSTEMATICS, Leiden, the Netherlands, August 10-14. Oral presentation.
Appelhans M, Imhof S, Weber HC. 2007. Specificity in colonization pattern as well as fungal identity of arbuscular mycorrhiza (AM) in Rutaceae. Botanikertagung, Hamburg, Germany, September 3-7. Poster presentation.
Appelhans MS, Janssens SB, Smets E, Keßler PJA. 2011. Age and historical biogeography of the pantropically distributed and species poor subfamily Spathelioideae (Rutaceae). IBC2011, XVIII International botanical congress, Melbourne, Australia, July 23-30. Oral presentation.

Field experience
Argentina and Chile (2003), Namibia (2004), Mallorca (2005), Austrian Alps (2005), Malta (2006, 2007), Italian and French Alps (2008), Jamaica and Cuba (2009), Borneo (2010)

Memberships in Botanical associations
Member of the „Deutsche Botanische Gesellschaft“
Member of the „International Association for Plant Taxonomy (IAPT)“

Webredactie Hortus botanicus - Last edited: 03 Apr 2012