Stefan Koller






Stefan Koller

Ph.D. student


Research Interests:

Changing environmental factors demand responses by the plant in order to thrive and survive. A finely tuned system is necessary to synchronize the energy uptake and energy use inside the leaf organs in order to produce biomass and avoid to damage. Water shortage (which is predicted to increase in southern Hesse) requires special attention, since CO2 and water vapor are both exchanged through the same structures. The loss of water through the stomata is the driving force for water uptake from the soil and for the cooling of the leafblade. The plants response to water shortage can be quite different between species. My research interest lies within the differential response to water shortage and increasing temperature on gas-exchange and functionality of the photosynthetic apparatus. A special interest lies in the quantification of inter- and intraspecific performance in stress and non-stressed situation and their spatial influence by non-destructive optical measurements. I focus my work on Mediterranean and Central-European Oak species with differential leaf traits and leaf longevity (deciduous and evergreen) in climate chamber /greenhouse experiments and exploratory observations on forest plantations in Hesse.

Topic of PhD-Thesis:
“Acclimation to increasing temperature and water shortage in European deciduous and evergreen Quercus species”

2004-2009: Study of Biology at the Johann Goethe University in Frankfurt

Diploma Thesis: Research into taxonomy and distribution of Zosimeidae Seifried (Copepoda: Harpacticoida) of the Great Meteor Seamount (Northeast Atlantic Ocean)


Koller, S., Jedmoski C., Kamm, K. & Brüggemann W. (2013): The South Hesse Oak Project (SHOP): Species- and site-specific efficiency of the photosynthetic apparatus of Mediterranean and Central European Oaks. Plant Biosystems

Koller, S., Holland, V. & Brüggemann W. (2013): Effects of drought stress on the evergreen Quercus ilex L., the deciduous Q. robur L. and their hybrid Q. x turneri Willd. Photosynthetica (in Press)

Holland, V., Koller, S. & Brüggemann W. (2013): Insight into the photosynthetic apparatus in evergreen and deciduous European oaks during autumnal senescence by using OJIP fluorescence transient analysis. Plant Biology. (In Press)

Koller, S & George, K.-H. (2011): Description of a new species of Zosime Boeck, 1872 (Copepoda: Harpacticoida: Zosimeidae) from the Great Meteor Seamount, representing one of the few eurybathic Harpacticoida among the distinct plateau and deep-sea assemblages. Meiofauna Marina, Vol.19, pp.109-126.

Poster Presentation:

Koller, S. & Brüggemann, W. (2013): Mediterranean Oaks – An option for drought prone Oak stands in southern Germany under climate change scenarios. Photosynthesis Research for Sustainability Conference in Baku, Azerbaijan.

Best Poster Award. Photosynthesis Research for Sustainability Conference in Baku, Azerbaijan.

Phone: +49 (0)69 798 42188