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Logo: HOT – Hanover Centre for Optical Technologies
Logo Leibniz Universität Hannover
Logo: HOT – Hanover Centre for Optical Technologies
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Microalgae - Resonance Raman spectroscopy of carotenoids in photosynthesis

In vivo kinetics of carotenoids in algae under light stress. Violaxanthin (lower trace) is down regulated during phases of excess lighting (arrow trace) while zeaxanthin (upper trace) is upregulated. The system recovers almost to dark state conditions within minutes when the light stress is ended.

The xanthophyll (violaxanthin) cycle is a major mechanism in the stress tolerance of plants. It involves the interconversion of carotenoid pigments to actively control energy dissipation in the light-harvesting complexes in order to protect the photosynthetic reaction centers from damage due to excess light energy.  In order to fully understand adaptation kinetics to varying light conditions in vivo, it is necessary to analyze this process non-invasively and in situ.

The first direct observation of violaxanthin cycle kinetics in vivo was accomplished at HOT applying state-of-the-art resonance Raman spectroscopy [http://onlinelibrary.wiley.com/doi/10.1002/jrs.5102/abstract] on carotenoids involved in photosynthesis. In this respect, resonance excitation profiles of three species of algae [http://onlinelibrary.wiley.com/doi/10.1002/jrs.5292/abstract] were studied as well. This project also involves algorithm design for baseline correction [http://onlinelibrary.wiley.com/doi/10.1002/jrs.5010/abstract].