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Optimal Quantum Yield of Photosystem II and Chlorophyll Degradation of Lobaria Pulmonaria in Relation to pH*

Published online by Cambridge University Press:  28 March 2007

Yngvar Gauslaa
Affiliation:
Department of Biology and Nature Conservation, Agricultural University of Norway, P.O. Box 5014, N-1432 As, Norway
Cor Kopperud
Affiliation:
Department of Biology and Nature Conservation, Agricultural University of Norway, P.O. Box 5014, N-1432 As, Norway
Knut Asbjørn Solhaug
Affiliation:
Department of Biology and Nature Conservation, Agricultural University of Norway, P.O. Box 5014, N-1432 As, Norway

Abstract

The FV/FM ratio of Lobaria pulmonaria with decreasing pH in samples from a boreal forest influenced by acid rain in SE Norway, suggesting that low pH has an effect on the optimal quantum yield of PSII. The pH was measured of distilled deionized water in which lobes from different habitats were rinsed, probably indicating the ionic environment of the lichen. The best prediction of FV/FM was found in a multiple regression model including the explanatory variables: pH, a/b-ratio and chlorophyll degradation measured as the 666/666a ratio, all correlated positively with FV/FM but not with each other. The commonly used chlorophyll degradation 435/415 ratio cannot be used for L. pulmonaria because of an unidentified, habitat-influenced brownish pigment with high absorbance in the 415–435 nm wavelength range.

Type
Research Article
Copyright
Copyright © British Lichen Society 1996

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Footnotes

*

Abbreviations: FO=minimal fluorescence in the dark-adapted stage; FM=minimal yield of fluorescence; FV=variable yield of fluorescence (i.e. FM − FO); FV/FM=optimal yield of PSII; PSII=photosystem II; 666/666a=absorbance ratio measured at 666 nm for fresh lobes and fully acified lobes (a); 435/415=absorbance ratio measured at 435 nm and 415 nm.

References

* Abbreviations: FO=minimal fluorescence in the dark-adapted stage; FM=minimal yield of fluorescence; FV=variable yield of fluorescence (i.e. FM − FO); FV/FM=optimal yield of PSII; PSII=photosystem II; 666/666a=absorbance ratio measured at 666 nm for fresh lobes and fully acified lobes (a); 435/415=absorbance ratio measured at 435 nm and 415 nm.