Responses of thallus anatomy and chlorophyll fluorescence-based photosynthetic characteristics of two Antarctic species of genus Usnea  to low temperature

Hájek, Josef; Hojdová, Andrea; Trnková, Kateřina; Váczi, Peter; Bednaříková, Michaela; Barták, Miloš

doi:10.32615/ps.2021.002

Cited by 7 publications

(1 citation statement)

References 46 publications

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“…Šabacká and Elster 2006, 4.0°C min -1 , Steiner et al 2021) to slow (Hájek et al 2012: 0.5°C min -1 ). Recently, linear cooling is frequently used for the evaluation of critical (cooling) temperature (Hájek et al 2021). In our study, we exploited the method of linear cooling in order to determine cryoresistance of several lichen species from polar regions.…”

Section: Introductionmentioning

confidence: 99%

What does critical temperature tell us about the resistance of polar lichens to freezing stress? Applicability of linear cooling method to ecophysiological studies.

Hájek¹,

Puhovkin²,

Giordano³

et al. 2023

Czech Polar Rep.

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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.

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Section: Introductionmentioning

confidence: 99%

What does critical temperature tell us about the resistance of polar lichens to freezing stress? Applicability of linear cooling method to ecophysiological studies.

Hájek¹,

Puhovkin²,

Giordano³

et al. 2023

Czech Polar Rep.

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Freezing temperature effects on photosystem II in Antarctic lichens evaluated by chlorophyll fluorescence

Andrzejowska,

Hájek,

Puhovkin

et al. 2024

Journal of Plant Physiology

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Cryoresistance Differences Between Species of Autotrops From Polar Regions Sensed by Chlorophyll Fluorescence

Puhovkin¹,

Hájek²,

Giordano³

et al. 2023

Probl Cryobiol Cryomed

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Lichens from the cold regions of Earth exhibit high, but different degree of tolerance to drought and freeze stresses. Therefore, three lichen species Xanthoria elegans, Umbilicaria cylindrica, Usnea sphacelata, and a representative of extremophilic cyanobacteria Nostoc commune were selected to measure temperature response curves of chlorophyll fluorescence parameters in cooling experiment using a constant rate of cooling from 20 to –45°C. Two chlorophyll fluorescence parameters (FV/FM – potential yield of photosynthetic processes in photosystem II and ΦPSII – effective quantum yield) were measured with a modulated fluorometer. For all experimental species, the temperature-response curves of II FV/FM and ΦPSII showed typical triphasic shape: plateau (temperature decrease from 20 to –5°C), decline, and a shoulder reaching the critical point. The phase typically formed a S-curve of different shape as dependent on species and chlorophyll fluorescence parameter. U. cylindrica was the most cryoresistant in terms of photosynthetic processes ongoing in thylakoid membrane of chloroplast at below zero temperature.

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Responses of thallus anatomy and chlorophyll fluorescence-based photosynthetic characteristics of two Antarctic species of genus Usnea to low temperature

Cited by 7 publications

References 46 publications

What does critical temperature tell us about the resistance of polar lichens to freezing stress? Applicability of linear cooling method to ecophysiological studies.

What does critical temperature tell us about the resistance of polar lichens to freezing stress? Applicability of linear cooling method to ecophysiological studies.

Freezing temperature effects on photosystem II in Antarctic lichens evaluated by chlorophyll fluorescence

Cryoresistance Differences Between Species of Autotrops From Polar Regions Sensed by Chlorophyll Fluorescence

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