What does critical temperature tell us about the resistance of polar lichens to freezing stress? Applicability of linear cooling method to ecophysiological studies.
J. Hájek, A. Puhovkin, Davide Giordano, Jiří Sekerák Jr.
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引用次数: 4
Abstract
Lichens from polar regions are well adapted to low temperature and considered cryoresistant. However, interspecific differences in their cryoresistance exist according to the degree of their adaptation and severity of the environment. In our study, we applied linear cooling technique in order to evaluate the interspecific differences in several lichen species. Thalli segments of Umbilicaria antarctica, Nephroma antarctica, Placopsis contortuplicata and Lasallia pustulata were exposed to the cooling from 20 to –35°C at a constant rate of 2°C min-1. Simultaneously with the cooling, chlorophyll fluorescence parameters evaluating potential (FV/FM) and effective yield of primary photochemical processes in PSII (FPSII) were measured in 30 s interval. Temperature response curves of FV/FM and FPSII formed typical S-curves that were species specific. Critical temperature (cooling point at which FPSII equals 0), was found in a narrow range of –25 to –28°C, suggesting that all experimental lichen species have a high resistance to sub-zero temperatures. The method of linear cooling used in this study has proven its applicability in ecophysiological studies since it is sensitive enough for the evaluation of species-specific differences in cryoresistance. This study describes different parameters that can be derived from the S-curves and discuss their proper use in ecophysiological and stress physiology studies.
Czech Polar ReportsAgricultural and Biological Sciences-Agricultural and Biological Sciences (all)
CiteScore
1.30
自引率
10.00%
发文量
22
期刊介绍:
Czech Polar Reports is an international, multidisciplinary, peer-reviewed journal. It is issued 2 times a year. The journal is dedicated to provide original research papers for sciences related to the polar regions and other planets with polar analogues. Czech Polar Reports covers the disciplines listed below. polar paleontology, geology, geochemistry, geomorphology, glaciology, climatology, hydrology, pedology, biochemistry, ecology, environmental science, microbiology, plant and animal biology including marine biology.