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Origin of chlorophyll fluorescence in plants at 55-75 degrees C.
- Source :
-
Photochemistry and photobiology [Photochem Photobiol] 2003 Jan; Vol. 77 (1), pp. 68-76. - Publication Year :
- 2003
-
Abstract
- The origin of heat-induced chlorophyll fluorescence rise that appears at about 55-60 degrees C during linear heating of leaves, chloroplasts or thylakoids (especially with a reduced content of grana thylakoids) was studied. This fluorescence rise was earlier attributed to photosystem I (PSI) emission. Our data show that the fluorescence rise originates from chlorophyll a (Chl a) molecules released from chlorophyll-containing protein complexes denaturing at 55-60 degrees C. This conclusion results mainly from Chl a fluorescence lifetime measurements with barley leaves of different Chl a content and absorption and emission spectra measurements with barley leaves preheated to selected temperatures. These data, supported by measurements of liposomes with different Chl a/lipid ratios, suggest that the released Chl a is dissolved in lipids of thylakoid membranes and that with increasing Chl a content in the lipid phase, the released Chl a tends to form low-fluorescing aggregates. This is probably the reason for the suppressed fluorescence rise at 55-60 degrees C and the decreasing fluorescence course at 60-75 degrees C, which are observable during linear heating of plant material with a high Chl a/lipid ratio (e.g. green leaves, grana thylakoids, isolated PSII particles).
Details
- Language :
- English
- ISSN :
- 0031-8655
- Volume :
- 77
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Photochemistry and photobiology
- Publication Type :
- Academic Journal
- Accession number :
- 12856885
- Full Text :
- https://doi.org/10.1562/0031-8655(2003)077<0068:oocfip>2.0.co;2