Publication details

Spatial pattern of low-temperature photoinhibition on thalli of Antarctic lichen species <i>Umbilicaria antarctica</i> visualized by a novel approach



Year of publication 2003
Type Article in Proceedings
Conference Book of Abstracts. 10th Congress of the European Society for Photobiology
MU Faculty or unit

Faculty of Science

Field Botany
Keywords photosynthesis; inhibition; Antarctica; lichen
Description Sensitivity of lichens to photoinhibition is believed to be more pronounced under full hydration and low temperature. In this study, we exposed Umbilicaria antarctica, a foliose Antarctic lichen species, to 30 min photoinhibitory treatment (1500 micromols m-2 s-1) under 5 degC. The extent of photoinhibition and rate of recovery were monitored as time courses of chlorophyll fluorescence parameters: Fv/Fm , PSII yield, and quenching coefficients. To visualize distribution of response of the parameters to photoinhibitory treatment over lichen thallus, we used a FuorCam (PSI, Czech Republic) device and imaging software. The novel approach enabled to distinguish a 0.1 square mm spots (pixels) over the thallus and relate the above parameters to each of them. Physiologically-active thallus zones forming irregular star-like shapes located close to thallus center showed high sensitivity to photoinhibition but also fast recovery. Less physiologically-active marginal parts of thallus were less affected by photoinhitory treatment but showed slower rate of recovery. The intrathalline differences in sensitity to photoinhibition were related to growth pattern of lichen thallus with umbilicate anatomy. The results sugget that U.antarctica showed high capacity of photoprotective mechanisms to cope with low-temperature photoinhibition which may help the species to survive high-light events during wet period of Antarctic spring/autumn.
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