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Hojdová, A./ Hájek, J. 2020: [Abstract:] Resistance of Antarctic lichens and unicellular alga Trebouxia sp. to extreme temperature: Laboratory study of linear cooling and shock freezing. - Czech Polar Reports 10(1): 144-146. [RLL List # 262 / Rec.# 42304]
Abstract: Usnea sphacelata and Usnea aurantiaco-atra are dominant components of Antarctic lichen flora in the South Shetlands archipelago and several other regions within maritime Antarctica. The lichens are considered to be cold resistant. They may survive long periods at sub zero temperature with no or only limited remarkable signs of damage. In majority of cases, however, the lichens face subzero temperature in dry, metabolically inactive state. When exposed to subzero temperature in wet state, lichens activate numerous protective mechanisms and reduce their photosynthetic activity. Rapid freezing of lichen thalli in wet state happens quite frequently in the field in polar regions. Consequences for lichen thallus anatomy and photosynthetic apparaus are, however, rather unknown. In our study, we focused on structural components of thallus of two Antarctic frusicose lichens (Usnea sphacelata and U. aurantiaco-atra) and their change after shock freezing (a short-term immersion of wet lichen thalli to liquid nitrogen). Anatomical properties of cross section of thalli were evaluated after the shock freezing and in untreated control. We expected species-specific differences in photosynthetic performance (monitored by several chlorophyll fluorescence parameters).
Notes: Extended abstract.
URL: https://www.sci.muni.cz/CPR/19cislo/Abstract/A12.pdf
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