Glutathione and zeaxanthin formation during high light stress in foliose lichens
| Authors | |
|---|---|
| Year of publication | 2006 |
| Type | Article in Periodical |
| Magazine / Source | Bulletin CSEBR |
| MU Faculty or unit | |
| Citation | |
| Field | Botany |
| Keywords | photoinhibition antioxidants lichen |
| Description | It was shown that the ratio of oxidized to reduced glutathione increased after treatment of thalli by high light. In lichens, majority of studies focused on glutathione were oriented to its dynamics during thallus desiccation. Involvement of glutathione into high light stress in lichens was studied in our experiments. Zeaxanthin (Z) is a xanthophyll-cycle pigment located in chloroplastic thylakoid membranes. It plays an important role in a dissipation of an excess energy. It is formed from a diepoxide violaxanthin via monoepoxide antheraxanthine. Deepoxidation of V is conditioned by presence of light. V recovers from Z in dark and there are several hypothesis trying to describe its mechanism. It is possible that Z functions as a direct acceptor of energy from excited chlorophyll a in a reaction centre of photosystem II. Z may interact and deactivate ROS. Another hypothesis postulates that Z changes conformation of light harvesting complexes and results in enhanced thermal dissipation of excess energy. The aim of our paper was to quantify glutathione and zeaxanthin dynamics during high light stress and recovery in two lichen species: Lasallia pustulata, Umbilicaria antarctica. |
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