Antioxidative mechanisms in a lichen <i>Lasallia pustulata</i> exposed to light and dehydration stress. s
| Title in English | Antioxidative mechanisms in a lichen <i>Lasallia pustulata</i> exposed to light and dehydration stress. |
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| Authors | |
| Year of publication | 2006 |
| Type | Article in Proceedings |
| Conference | FESPB 2006 Congress: Book of Abstracts |
| MU Faculty or unit | |
| Citation | |
| Web | Congress website |
| Field | Botany |
| Keywords | glutathione, zeaxanhtin, DEPS, photosynthesis, chlorophyll fluorescence |
| Description | In photosynthetizing partners of lichens, majority of stresses produce reactive oxygen species (ROS). Negative effects of ROS are alleviated by antioxidants, e.g. zeaxanthin, glutathione, catalase, superoxidedismutase. In previous studies, we demonstrated that the capacity of zeaxanthin (Z) formation is sufficient to cope with a high light (HL) stress in fully hydrated lichen thalli. The aim of presented study is to evaluate the dynamics of antioxidants in algal partner of L. pustulata exposed to several HL and dehydration regimes. Treated by a short-term HL (typically 1800 micromol m-2 s-1), hydrated lichens showed photoinhibition of photosynthesis (decrease in Fv/Fm, Yield PSII, increase in NPQ) and activation of antioxidative mechanisms. Z increased and DEPS reached 0.5, total glutathione decreased to a half of control and was largely oxidized. The changes were reversible, the above parameters reached pre-treated values within 10-24 h relaxation in dark. Dehydration at dark and LL (300 micromol m-2 s-1) led to the same DEPS in dry state reached after 5 h. However, DEPS increased more rapidly in LL than in dark during the early dehydration (water potential 0 to -10 MPa). |
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