J 2016

Sensitivity of photosynthetic processes to freezing temperature in extremophilic lichens evaluated by linear cooling and chlorophyll fluorescence

HÁJEK, Josef, Miloš BARTÁK, Jana HAZDROVÁ and Marie FORBELSKÁ

Basic information

Original name

Sensitivity of photosynthetic processes to freezing temperature in extremophilic lichens evaluated by linear cooling and chlorophyll fluorescence

Authors

HÁJEK, Josef (203 Czech Republic, guarantor, belonging to the institution), Miloš BARTÁK (203 Czech Republic, belonging to the institution), Jana HAZDROVÁ (203 Czech Republic, belonging to the institution) and Marie FORBELSKÁ (203 Czech Republic, belonging to the institution)

Edition

Cryobiology, Academic Press, 2016, 0011-2240

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10600 1.6 Biological sciences

Country of publisher

United States of America

Confidentiality degree

není předmětem státního či obchodního tajemství

Impact factor

Impact factor: 1.996

RIV identification code

RIV/00216224:14310/16:00091424

Organization unit

Faculty of Science

UT WoS

000389010600005

Keywords in English

Usnea antarctica; Usnea aurantiaco-atra; Umbilicaria cylindrica; cryoresistance; Antarctica; James Ross Island; temperature stress

Tags

Tags

International impact, Reviewed
Změněno: 13/4/2017 21:54, Ing. Andrea Mikešková

Abstract

V originále

Extremophilic lichens and their photosynthesizing photobionts from the cold regions of Earth are adapted to perform photosynthesis at subzero temperatures. To evaluate interspecific differences in the critical temperature for primary photochemical processes of photosynthesis, we exposed lichen thalli of Usnea antarctica, Usnea aurantiaco-atra, and Umbilicaria cylindrica to linear cooling from +20 to minus 50 °C at a constant rate of 2 °C/min. Simultaneously, two chlorophyll fluorescence parameters (FV/FM: potential yield of photosynthetic processes in photosystem II, YieldPSII: effective quantum yield of PS II) evaluating a gradual subzero temperature-induced decline in photosynthetic processes were measured by a modulated fluorometer. For the studied species, the response of FV/FM and YieldPSII to declining temperature showed an S-curve shape. The decline in FV/FM and YieldPSII at low temperatures started at minus 5 and +5 °C, respectively in the majority of cases. The decline was, however, species-specific. U. aurantiaco-atra showed a constant-rate decline of YieldPSII from the physiological temperature 20 °C. U. antarctica exhibited the first sign of FV/FM decline at minus 12 °C. The critical temperature related to full inhibition of the photosynthetic processes in PSII (FV/FM), was found at minus 20 °C. However, this occurred at minus 30 °C for U. cylindrica. In an individual sample, the critical temperature for FV/FM was typically lower than for YieldPSII. The method of linear cooling combined with simultaneous measurements of chlorophyll fluorescence parameters proved to be an efficient tool in the estimation of extremophilic species sensitivity/resistance to freezing.

Links

LM2010009, research and development project
Name: Projekt CzechPolar - České polární stanice: Stavba a operační náklady
Investor: Ministry of Education, Youth and Sports of the CR
LM2015078, research and development project
Name: Česká polární výzkumná infrastruktura (Acronym: CzechPolar2)
Investor: Ministry of Education, Youth and Sports of the CR