Experimental freezing of freshwater pennate diatoms from polar habitats

Hejduková, Eva; Nedbalová, Linda

doi:10.1007/s00709-021-01648-8

Cited by 5 publications

(1 citation statement)

References 115 publications

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“…Measurements of most frequent ChlF parameters (potential (F V /F M ), and effective yield of photosynthetic processes in PSII ( PSII )) are either done in temperature equilibrated state (exposition lasts typically tens of minutes to hours, see e.g. Mishra et al 2015, Hejduková andNedbalová 2021) or during cooling the sample at constant rate. The latter technique is called linear cooling with concurrent measurements of ChlF parameters.…”

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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Land cover and use-history of large empty spaces at fortified Iron Age hilltop sites; a case study from La Terrasse, Bibracte oppidum

Hajnalová,

Goláňová,

Jamrichová

et al. 2023

Veget Hist Archaeobot

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The research of Iron Age oppida and hillforts plays a significant role in understanding the urbanisation processes throughout the European continent. The habitation and built-up areas have always been in the limelight of both traditional and environmental archaeological research. However, at many oppida, there were also large, unoccupied empty spaces. As they are crucial for understanding these settlements’ internal organisation, their functions are debated. Here we aim to demonstrate that seldom studied archaeobotanical archives preserve information on their use-history. By implementing a multiproxy approach, we seek to answer questions on the development, land use and vegetation history of one important open space at Bibracte oppidum on Mont Beuvray. Through the correlation of pollen, phytoliths, diatoms, charcoal, seeds, and parasites with radiocarbon dating we collected evidence of archaeologically otherwise untraceable human activities and detected a much more complicated history of the studied area. We show that it was repeatedly used in the last eight millennia and was never farmed or built up. During the phases of its most intensive exploitation in the Late Iron Age (La Tène) and Early Middle Ages (Merovingian) periods, it was kept as grassland. Our research lays down the foundation for the wider implementation of archaeobotany into projects that aim to clarify the uses and functions of enigmatic large open spaces, not only from the Iron Age but also from other periods.

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Ultrastructure of plant cells

Holzinger

2021

Protoplasma

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Experimental freezing of freshwater pennate diatoms from polar habitats

Cited by 5 publications

References 115 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.

Land cover and use-history of large empty spaces at fortified Iron Age hilltop sites; a case study from La Terrasse, Bibracte oppidum

Ultrastructure of plant cells

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