Capacity of Antarctic lichen Xanthoria elegans to synthetize photoprotective secondary compounds is affected by supplemetary UV-B doses
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| Year of publication | 2014 |
| Type | Conference abstract |
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| Description | Lichen thalli of X. elegans were collected at James Ross Island (Antarctica). They were dried under natural field conditions and then transported to the laboratory in Brno, Czech Republic. Before experiments, the thalli were re-wetted for 48 h by demineralized water and wet cellulose sheet located beneath the thalli. During re-wetting, the thalli were exposed to a dim light (20 micromol m-2 s-1 of PAR) at 5oC. Duration of exposition to free supplemental UV-B was 7 days. Three different intensities of UV-B radiaton were used (0.9 W.m-2, 1.4 W.m-2 and 3.0 W.m-2, in the second cycle 0.9 W.m-2, 1.15 W.m-2, 1.4 W.m-2). Samples for further analysis were taken during the exposition after 5, 10, 24, 48 and 168 h. During the exposition chlorophyll fluorescence parameters were measured using an approach of Kautsky kinetics supplemented with quenching analysis. Time courses of the following parameters were measured: Fv/Fm, Yield PSII, non-photochemical quenching (NPQ, qN) during exposition: 5, 10, 24, 48, and 168 h. After the exposition, UV-B absorbing compounds, pigment contents and concentration of glutathione were measured. UV-B induced synthesis of photoprotective compounds was measured using spectral absorption curves of extracts made in ethanol extracts. Amount of UV-B absorbing compounds was then evaluated according to the analysis of spectral absorbance curves. Chlorophyll and carotenoid contents were measured by a spectrophotometre (Specord, Analytik Jena). Glutathione was analysed using a method of thiol groups labeling. |
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