Activity of primary photosynthetic processes in some antarctic
lichens and mosses at decreasing water potential of their
thalli

J 2004

Activity of primary photosynthetic processes in some antarctic lichens and mosses at decreasing water potential of their thalli

BARTÁK, Miloš and Jan GLOSER

Basic information

Original name

Activity of primary photosynthetic processes in some antarctic lichens and mosses at decreasing water potential of their thalli

Name in Czech

Aktivita primárních fotosyntetických procesů u některých antrktických lišejníků a mechů v podmínkách klesajího vodního potenciálu jejich stélek

Authors

BARTÁK, Miloš (203 Czech Republic, guarantor) and Jan GLOSER (203 Czech Republic)

Edition

Terra Nostra, Schriften der Alfred-Wegener-Stiftung, Bremen, Alfred Wegener Institut, Bremen, 2004, 0946-8978

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10600 1.6 Biological sciences

Country of publisher

Germany

Confidentiality degree

není předmětem státního či obchodního tajemství

References:

URL

RIV identification code

RIV/00216224:14310/04:00011017

Organization unit

Faculty of Science

Keywords in English

quantum yield; photosystem II; dehydration; poikilohydric organisms; critical water potential

Abstract

ORIG CZ

V originále

It is generally accepted, that water availability is the most important factor limiting photosynthetic processes and growth of autotrophic organisms in antarctic terrestrial ecosystems. In spite of this fact, our knowledge of the relationships between photosynthetic activity and internal water availability (expressed as water potential of assimilating tissues) of antarctic lichens and mosses is still quite fragmentary. In this study, we have tried to define the dependence of primary photosynthetic processes on water potential of thalli in several species of lichens and mosses widely distributed in maritime Antarctica. The measurement were done in a field laboratory of Vernadsky (former Faraday) Station at the Galindez Island (Argentine Islands, 65o 15 S, 64o 16 W) in February 2003. Wet samples of four lichen species (Umbilicaria antarctica, Xanthoria elegans, Stereocaulon glabrum, Sphaerophorus globosus) and two mosses (Polytrichum alpestre, Sanionia uncinata) were placed on plastic dishes (diameter 35 mm, height 10 mm) and subjected to slow desiccation at room temperature and air humidity (about 20 C and 40 %, respectively). Thallus water potential (WP) and quantum yield of photochemical reactions in photosystem II (FII) were measured simultaneously during desiccation until any activity of photochemical processes was detectable. Dew point water potential meter WP4-T (Decagon, USA) and FL-100 modulated fluorometer (OptiScience, USA) were used for the measurements. Relation of FII to WP was found curvilinear with more or less constant FII in high WP and decreasing FII towards low WP. Optimum WP for primary photosynthetic processes was found both for lichens and mosses in the range of 0 to 10 MPa, in which the FII reached maximum value of 0.5-0.6. At lower WP (from 10 to 20 MPa), steep decrease of FII was found, more pronounced in mosses than lichens. Critical values of WP for photosynthesis (= zero FII) were higher in mosses (about -25 MPa) than in lichens (from -30 to -40 MPa). Our measurements documented that not only poikilohydric antarctic lichens, but also mosses are capable to maintain some photosynthetic activity at extremely low water potential of their thalli. This gives them an advantage to prolong their positive carbon balance or diminish the respiration losses during dry periods of a day or season.

In Czech

Publikace popisuje stanovení kritického vodního potenciálu vybraných poikilohydrických autotrofů. Fotochemické procesy fotosyntézy byly aktivní i v podmínkách silné dehydrace stélek studovaných antarktických mechů a lišejníků. Vodní potenciál kritický pro fotochemické procesy fotosyntézy se pro jednotlivé druhy pohyboval v intervalu -25 anč -45 MPa.

Links

MSM 143100007, plan (intention)

Name: Ekologie pobřežní antarktické vegetační oázy

Investor: Ministry of Education, Youth and Sports of the CR, Ecology of the coastal vegetation

Citovat

BARTÁK, Miloš and Jan GLOSER. Activity of primary photosynthetic processes in some antarctic lichens and mosses at decreasing water potential of their thalli. Terra Nostra, Schriften der Alfred-Wegener-Stiftung. Bremen: Alfred Wegener Institut, Bremen, 2004, vol. 2004, No 4, p. 107-108. ISSN 0946-8978.

@article{567200,
   author = {Barták, Miloš and Gloser, Jan},
   article_location = {Bremen},
   article_number = {4},
   keywords = {quantum yield; photosystem II; dehydration; poikilohydric organisms; critical water potential},
   language = {eng},
   issn = {0946-8978},
   journal = {Terra Nostra, Schriften der Alfred-Wegener-Stiftung},
   title = {Activity of primary photosynthetic processes in some antarctic lichens and mosses at decreasing water potential of their thalli},
   url = {http://www.scar28.org/SCAR/SCARmeeting/Wednesday/PDF/S_01_poster.pdf},
   volume = {2004},
   year = {2004}
}

TY  - JOUR
ID  - 567200
AU  - Barták, Miloš - Gloser, Jan
PY  - 2004
TI  - Activity of primary photosynthetic processes in some antarctic lichens and mosses at decreasing water potential of their thalli
JF  - Terra Nostra, Schriften der Alfred-Wegener-Stiftung
VL  - 2004
IS  - 4
SP  - 107-108
EP  - 107-108
PB  - Alfred Wegener Institut, Bremen
SN  - 09468978
KW  - quantum yield
KW  - photosystem II
KW  - dehydration
KW  - poikilohydric organisms
KW  - critical water potential
UR  - http://www.scar28.org/SCAR/SCARmeeting/Wednesday/PDF/S_01_poster.pdf
N2  - It is generally accepted, that water availability is the most important factor limiting photosynthetic processes and growth of autotrophic organisms in antarctic terrestrial ecosystems. In spite of this fact, our knowledge of the relationships between photosynthetic activity and internal water availability (expressed as water potential of assimilating tissues) of antarctic lichens and mosses is still quite fragmentary. In this study, we have tried to define the dependence of primary photosynthetic processes on water potential of thalli in several species of lichens and mosses widely distributed in maritime Antarctica. The measurement were done in a field laboratory of Vernadsky (former Faraday) Station at the Galindez Island (Argentine Islands, 65o 15 S, 64o 16 W) in February 2003. Wet samples of four lichen species (Umbilicaria antarctica, Xanthoria elegans, Stereocaulon glabrum, Sphaerophorus globosus) and two mosses (Polytrichum alpestre, Sanionia uncinata) were placed on plastic dishes (diameter 35 mm, height 10 mm) and subjected to slow desiccation at room temperature and air humidity (about 20 C and 40 %, respectively). Thallus water potential (WP) and quantum yield of photochemical reactions in photosystem II (FII) were measured simultaneously during desiccation until any activity of photochemical processes was detectable. Dew point water potential meter WP4-T (Decagon, USA) and FL-100 modulated fluorometer (OptiScience, USA) were used for the measurements. Relation of FII to WP was found curvilinear with more or less constant FII in high WP and decreasing FII towards low WP. Optimum WP for primary photosynthetic processes was found both for lichens and mosses in the range of 0 to 10 MPa, in which the FII reached maximum value of 0.5-0.6. At lower WP (from 10 to 20 MPa), steep decrease of FII was found, more pronounced in mosses than lichens. Critical values of WP for photosynthesis (= zero FII) were higher in mosses (about -25 MPa) than in lichens (from -30 to -40 MPa). Our measurements documented that not only poikilohydric antarctic lichens, but also mosses are capable to maintain some photosynthetic activity at extremely low water potential of their thalli. This gives them an advantage to prolong their positive carbon balance or diminish the respiration losses during dry periods of a day or season.
ER  -

BARTÁK, Miloš and Jan GLOSER. Activity of primary photosynthetic processes in some antarctic lichens and mosses at decreasing water potential of their thalli. \textit{Terra Nostra, Schriften der Alfred-Wegener-Stiftung}. Bremen: Alfred Wegener Institut, Bremen, 2004, vol.~2004, No~4, p.~107-108. ISSN~0946-8978.

Detailed Information on Publication Record