I am integrating studies in the field of comparative plant anatomy, ecology, physiology, and phylogeny with the ultimate goal of understanding ecological and evolutionary patterns of plant diversity. Given the important role of plants in tackling major, global problems such as climate change, food security, and alternatives for fossil fuels, there is an urgent need to focus on plant diversity and sustainable use of natural resources.

A recent topic in my research activities relates to large-scale tree mortality and climate-induced changes in forest composition and function. While woody plants from wet and dry forest biomes appear to show an equal relative vulnerability to drought-induced failure of their water transport system, more research is needed to understand (1) the direct effects of extreme drought events at the species and intraspecific (population) level of dominant tree species, and (2) the indirect effects through interactions with other climate-related disturbances (e.g., wildfires, pests and pathogens) and changes in forest management and land use. Obviously, addressing these issues requires collaboration with scientists from various disciplines. The contributions of my working group in Ulm towards these issues mainly focus on structure-function relationships of xylem tissue, water transport processes in plants, and a broad, synthetic approach of this complex issue, which is a prerequisite to predict future tree distribution.

Given my background in comparative plant anatomy, most research activities have a strong input of wood anatomical observations. Special attention in current projects is given to: (1) the importance of pit membranes in water conducting cells for understanding hydraulic efficiency and safety, (2) the functional role and evolutionary patterns of ray and axial parenchyma in wood, and (3) the mechanisms of embolism repair (i.e., refilling of embolisedxylem conduits). Methods applied include measurements of morphological and anatomical features, but also physiological processes in the field and in the lab, and microclimate in the field. Visualisation of structural details includes a wide range of microscope techniques, such as immunolabelling, transmission and scanning electron microscopy (SEM, TEM), atomic force microscopy (AFM), X-ray computed tomography (microCT), and nuclear magnetic resonance (NMR) imaging.

Current work on aluminium (Al) accumulation in plants (i.e., the uptake of Al in aboveground plant tissues in concentrations above 1,000 ppm) builds on my earlier systematic surveys and is mainly focussed on tropical plants. A central question is how accumulators and excluders co-exist and compete with each other across various vegetation and soil types. Understanding how exactly accumulators take up Al and detoxify it in their leaves, bark, and wood tissue may provide useful information for better understanding Al toxicity, which represents one of the major problems for cultivating various crops in acidic soils worldwide. Indonesian plants that belong to the Al accumulating genus Symplocosare investigated to explore optimal growth conditions for cultivation and to develop a sustainable way for Indonesian weavers to use these plantsfor traditional dye techniques.

Current projects

  • German Science Foundation, DFG: “International Workshop on Plant Hydraulic Techniques”, Ulm University, 17-19 September 2014.
  • German Science Foundation, DFG: “Evolutionary and functional traits of parenchyma in the hydraulic architecture of plants”, 1 April 2013 –30 June 2016.
  • DAAD: “Xylem analysis of crop plants under drought”, joint application with the University of Belgrade (Serbia), January 2013 – December 2014.
  • Ministry for Science, Research, and the Arts, Baden-Wurttemberg, Germany, Juniorprofessoren-Programm: “Aluminium uptake in Symplocos trees and sustainable use of dye plants by Indonesian weavers”, January 2013 - December 2015.
  • National Science Foundation:Water in, air out: Mechanisms of xylem embolism repair in seed plants”. Prof.Dr.Jochen Schenk (Fullerton State University, California, USA) is Principal Investigator, I am Co-PI; 1/4/2012 – 31/3/2015.

Selection of previous projects

  • Ministry for Science, Research, and the Arts, Baden-Wurttemberg, Germany, Juniorprofessorenprogramm: “The relationship between microscopic hydraulic networks and water transport in plants”. 1 November 2009 – 30April 2013.
  • European Science Foundation (ESF):The significance of xylem hydraulic plasticity for reconstructing past environments”, organisation of a workshop at Kippel (Switzerland) with Dr. P. Fonti (WSL, Switzerland), 15-17 May 2012.
  • Royal Society International Joint Project, UK: “The physiology and anatomy of drought resistance in conifers”, project with Dr S. Delzon (University of Bordeaux, France), February 2009 – 31 May 2012.
  • Australian Research Council – New Zealand Research Network for Vegetation Function Working Group: “Xylem Functional Traits”, organization of workshop at Macquarie University (Sydney) with Dr. B. Choat, October 2009.
  • Visiting Professorship at the University of Bordeaux 1: “Forest species distribution and climate change: drought resistance (cavitation) in conifer trees”, February 2009 – August 2009.
  • NERC-New Investigators competition, UK: “Structure and function of pit membranes in water conduction pathways of plants: combining novel microscopy techniques with xylem hydraulic experiments”, 23 September 2006 – 22 May 2008.
  • Royal Society Research Grant, UK: “How do vessel pits enable water flow? Evidence from atomic force microscopy (AFM) and X-ray computed tomography (microCT) of wood”, 4 August 2006 – 3 August 2007.
  • The Daiwa Anglo-Japanese Foundation, UK:Electron microscope observations of pit membranes with central thickenings: an overlooked wood anatomical character in angiosperms”, 22 november 2004 - 22 november 2005.
  • “KredietaanNavorsers”, F.W.O.-Flanders, Belgium: “The distribution, function and systematic significance of selected wood and leaf anatomical characters in flowering plants”, 01/01/2003 - 03/07/2004.