Abstract
Thermal emission and photochemical energy storage were examined in photosystem I reaction center/core antenna complexes (about 40 Chl a/P700) using photoacoustic spectroscopy. Satisfactory signals could only be obtained from samples bound to hydroxyapatite and all samples had a low signal-to-noise ratio compared to either PS I or PS II in thylakoid membranes. The energy storage signal was saturated at low intensity (half saturation at 1.5 W m-2) and predicted a photochemical quantum yield of >90%. Exogenous donors and acceptors had no effect on the signal amplitudes indicating that energy storage is the result of charge separation between endogenous components. Fe(CN)6-3 oxidation of P700 and dithionite-induced reduction of acceptors FA-FB inhibited energy storage. These data are compatible with the hypothesis that energy storage in PS I arises from charge separation between P700 and Fe-S centers FA-FB that is stable on the time scale of the photoacoustic modulation. High intensity background light (160 W m-2) caused an irreversible loss of energy storage and correlated with a decrease in oxidizable P700; both are probably the result of high light-induced photoinhibition. By analogy to the low fluorescence yield of PS I, the low signal-to-noise ratio in these preparations is attributed to the short lifetime of Chl singlet excited states in PS I-40 and its indirect effect on the yield of thermal emission.
| Original language | English |
|---|---|
| Pages (from-to) | 201-208 |
| Number of pages | 8 |
| Journal | Photosynthesis Research |
| Volume | 24 |
| Issue number | 3 |
| DOIs | |
| State | Published - Jun 1 1990 |
| Externally published | Yes |
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Keywords
- energy conversion
- P700
- photosynthesis
- quantum yield
- thermal emission
ASJC Scopus subject areas
- Plant Science
Cite this
Detection of photosynthetic energy storage in a photosystem I reaction center preparation by photoacoustic spectroscopy. / Owens, Thomas G.; Carpentier, Robert; Leblanc, Roger.
In: Photosynthesis Research, Vol. 24, No. 3, 01.06.1990, p. 201-208.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Detection of photosynthetic energy storage in a photosystem I reaction center preparation by photoacoustic spectroscopy
AU - Owens, Thomas G.
AU - Carpentier, Robert
AU - Leblanc, Roger
PY - 1990/6/1
Y1 - 1990/6/1
N2 - Thermal emission and photochemical energy storage were examined in photosystem I reaction center/core antenna complexes (about 40 Chl a/P700) using photoacoustic spectroscopy. Satisfactory signals could only be obtained from samples bound to hydroxyapatite and all samples had a low signal-to-noise ratio compared to either PS I or PS II in thylakoid membranes. The energy storage signal was saturated at low intensity (half saturation at 1.5 W m-2) and predicted a photochemical quantum yield of >90%. Exogenous donors and acceptors had no effect on the signal amplitudes indicating that energy storage is the result of charge separation between endogenous components. Fe(CN)6-3 oxidation of P700 and dithionite-induced reduction of acceptors FA-FB inhibited energy storage. These data are compatible with the hypothesis that energy storage in PS I arises from charge separation between P700 and Fe-S centers FA-FB that is stable on the time scale of the photoacoustic modulation. High intensity background light (160 W m-2) caused an irreversible loss of energy storage and correlated with a decrease in oxidizable P700; both are probably the result of high light-induced photoinhibition. By analogy to the low fluorescence yield of PS I, the low signal-to-noise ratio in these preparations is attributed to the short lifetime of Chl singlet excited states in PS I-40 and its indirect effect on the yield of thermal emission.
AB - Thermal emission and photochemical energy storage were examined in photosystem I reaction center/core antenna complexes (about 40 Chl a/P700) using photoacoustic spectroscopy. Satisfactory signals could only be obtained from samples bound to hydroxyapatite and all samples had a low signal-to-noise ratio compared to either PS I or PS II in thylakoid membranes. The energy storage signal was saturated at low intensity (half saturation at 1.5 W m-2) and predicted a photochemical quantum yield of >90%. Exogenous donors and acceptors had no effect on the signal amplitudes indicating that energy storage is the result of charge separation between endogenous components. Fe(CN)6-3 oxidation of P700 and dithionite-induced reduction of acceptors FA-FB inhibited energy storage. These data are compatible with the hypothesis that energy storage in PS I arises from charge separation between P700 and Fe-S centers FA-FB that is stable on the time scale of the photoacoustic modulation. High intensity background light (160 W m-2) caused an irreversible loss of energy storage and correlated with a decrease in oxidizable P700; both are probably the result of high light-induced photoinhibition. By analogy to the low fluorescence yield of PS I, the low signal-to-noise ratio in these preparations is attributed to the short lifetime of Chl singlet excited states in PS I-40 and its indirect effect on the yield of thermal emission.
KW - energy conversion
KW - P700
KW - photosynthesis
KW - quantum yield
KW - thermal emission
UR - http://www.scopus.com/inward/record.url?scp=0000986199&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0000986199&partnerID=8YFLogxK
U2 - 10.1007/BF00032307
DO - 10.1007/BF00032307
M3 - Article
AN - SCOPUS:0000986199
VL - 24
SP - 201
EP - 208
JO - Photosynthesis Research
JF - Photosynthesis Research
SN - 0166-8595
IS - 3
ER -