Localization and mechanisms of energy dissipation in plants

• Antragsteller: Professor Dr. Alfred R. Holzwarth; Professor Dr. Peter Jahns
• Fachliche Zuordnung: Biochemie und Biophysik der Pflanzen
• Förderung: Förderung von 2011 bis 2016
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 201199981

The high-light-induced conversion of excess excitation energy (i.e. light energy, which is absorbed by the antenna, but not utilized for photosynthesis) into heat is an efficient and crucial photoprotective mechanism allowing optimal plant growth. The basis of these processes, called non-photochemical quenching (= NPQ) of excitation energy is controversially discussed (LHCII aggregation vs. direct zeaxanthin and/or lutein quenching in the antenna proteins of photosystem II). We have established new measuring systems that allows us to characterize in detail the NPQ processes under physiological conditions in intact leaves by means of time-resolved chlorophyll fluorescence and transient absorption spectroscopy. Our studies resulted in a new in vivo NPQ model. This shows that LHCII oligomerization and zeaxanthin dependent quenching contribute independently and at different quenching sites to total NPQ. Applying ultrafast fluorescence and transient absorption spectroscopy in combination with other established techniques to intact leaves and chloroplasts of Arabidopsis (wild type and specific mutants) we aim to characterize in detail the dynamics and the molecular mechanisms of the two quenching processes.

• DFG-Verfahren: Sachbeihilfen