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Desiccation-induced non-radiative dissipation in isolated green lichen algae
Paul Christian Wieners1, Opayi Mudimu, Wolfgang Bilger
1Botanical Institute, Christian-Albrechts-University Kiel, Olshausenstr. 40, 24098, Kiel, Germany.
Photosynthesis Research
|July 27, 2012
Summary
Lichens protect themselves from high light damage when dry through non-radiative dissipation (NRD). Specific micronutrients in seawater enhance this photoprotective mechanism in lichen algae.
Area of Science:
- Plant Physiology
- Photobiology
- Lichenology
Background:
- Lichens withstand desiccation but are vulnerable to photodamage when dry.
- Photosynthesis halts in desiccated lichens, blocking energy use and increasing photodamage risk.
- High light and desiccation often coexist in exposed lichen habitats, yet photodamage is minimal.
Purpose of the Study:
- To investigate the photoprotective role of non-radiative dissipation (NRD) in desiccated lichen algae.
- To provide evidence for NRD as a protective mechanism against photodamage in lichens.
- To identify factors influencing NRD in lichen symbionts.
Main Methods:
- Used isolated green algae (Coccomyxa sp., Trebouxia asymmetrica) for reproducible desiccation experiments.
- Measured chlorophyll fluorescence (F(0) and F(V)/F(M)) to assess NRD and photodamage.
- Varied culture conditions, including trehalose, seawater, and specific micronutrients (ZnCl2, NaI).
Main Results:
- Basal fluorescence (F(0)) quenching indicated strong NRD in desiccated algae.
- Culture in seawater enhanced F(0) quenching and reduced photodamage (F(V)/F(M) depression) in T. asymmetrica.
- Specific micronutrients (ZnCl2, NaI) mimicked seawater's effect, suggesting their role in NRD.
Conclusions:
- Non-radiative dissipation (NRD), indicated by F(0) quenching, is a photoprotective mechanism in desiccated lichen algae.
- The development of NRD is partly dependent on essential micronutrients.
- Understanding these mechanisms is crucial for lichen survival in harsh environments.
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