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@article{635688,
author = {Hájek, Josef and Barták, Miloš and Dubová, Jaroslava},
article_location = {Dordrecht},
article_number = {4},
keywords = {photosynthesis; water potential; dehydration; Lasallia pustulata; Umbilicaria hirsuta; sucrose; chlorophyll fluorescence; thallus anatomy},
language = {eng},
issn = {0006-3134},
journal = {Biologia Plantarum},
note = {accepted 17 October 2005},
title = {Inhibition of photosynthetic processes in foliose lichens induced by temperature and osmotic stress.},
volume = {50},
year = {2006}
}
TY - JOUR
ID - 635688
AU - Hájek, Josef - Barták, Miloš - Dubová, Jaroslava
PY - 2006
TI - Inhibition of photosynthetic processes in foliose lichens induced by temperature and osmotic stress.
JF - Biologia Plantarum
VL - 50
IS - 4
SP - 624-634
EP - 624-634
PB - KLUWER ACADEMIC PUBLISHERS
SN - 00063134
N1 - accepted 17 October 2005
KW - photosynthesis
KW - water potential
KW - dehydration
KW - Lasallia pustulata
KW - Umbilicaria hirsuta
KW - sucrose
KW - chlorophyll fluorescence
KW - thallus anatomy
N2 - Negative effects of osmotically-induced dehydration of two foliose lichen species, Lasallia pustulata and Umbilicaria hirsuta, was studied at physiological (22 deg C), low (5 deg C) and freezing temperature (-10 deg C), using chlorophyll (Chl) fluorescence. In both species, exposition to increasing sucrose concentrations led to a pronounced decrease in potential (FV/FM), and actual (Fi2) quantum yields of photochemical processes in photosystem 2. Lasallia pustulata was more sensitive to osmotic stress, because comparable osmotic dehydration inhibited FV/FM, Fi2 more than in Umbilicaria hirsuta. In our study, critical concentration of sucrose that fully inhibited photochemical processes of photosynthesis was 2.5 M, which represented water potential (ŁZ) of ĄV18.8 MPa. Decrease in background Chl fluorecsence (F0) and increase in non-photochemical quenching (qN) revealed two phases of osmotic stress in lichens: phase I with no change (ŁZ 0 to -6.6 MPa) and phase II (ŁZ -11.3 to -18.8 MPa) typical by substantial change in Chl fluorescence parameters. Effects of thallus anatomy on species-specific response to osmotic dehydration is discussed and attributed to results obtained by optical microscopy and Chl fluorescence imaging technique.
ER -
HÁJEK, Josef, Miloš BARTÁK and Jaroslava DUBOVÁ. Inhibition of photosynthetic processes in foliose lichens induced by temperature and osmotic stress. \textit{Biologia Plantarum}. Dordrecht: KLUWER ACADEMIC PUBLISHERS, 2006, vol.~50, No~4, p.~624-634, 10 pp. ISSN~0006-3134.
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