TY - JOUR
T1 - Cyclic electron flow around PSI functions in the photoinhibited rice leaves
AU - Kubo, Satoshi
AU - Masumura, Takehiro
AU - Saito, Yuhi
AU - Fukayama, Hiroshi
AU - Suzuki, Yuji
AU - Sugimoto, Toshio
AU - Makino, Amane
AU - Amako, Katsumi
AU - Miyake, Chikahiro
PY - 2011/2/1
Y1 - 2011/2/1
N2 - We investigated the regulation mechanism of cyclic electron flow around photosystem I (CEF-PSI) in the rice leaves which suffered from photosystem II (PSII) photoinhibition. High-light (HL) treatment [2000 μmol photon m-2 s-1 at 0% carbon dioxide (CO2), 2% oxygen (O2) and 25°C] of rice leaves decreased both the maximum quantum efficiency of PSII (Fv/Fm) and the light-dependent O2-evolution rate [V(O2)]. High-light treatment did not affect the relative electron flux in PSI [Φ(PSI) × PFD]. In non-treated leaves, increasing in the photon flux density (PFD) enhanced V(O2), Φ(PSI) × PFD and the ratio of oxidized P700 to total P700 [(P700+)/(P700)total]. Φ(PSI) × PFD continued to increase even after the saturation of V(O2) against PFD. These results suggested that the electrons not used for the major electron sink, photosynthetic carbon reduction-cycle, did turnover in PSI, that is, CEF-PSI functioned at a higher PFD. High-light treatments did not affect the activity of CEF-PSI and increased (P700+)/(P700)total in the lower PFDs, compared to non-treated leaves. The activity of CEF-PSI depends on the amount of oxidized PQ. Photoinhibition of PSII suppressed electron influx from PSII to photosynthetic linear electron transport. The enhanced (P700+)/(P700)total suggested the increase in the ratio of oxidized plastoquinone (PQ) to total PQ, which supported the activity of CEF-PSI in the photoinhibited leaves.
AB - We investigated the regulation mechanism of cyclic electron flow around photosystem I (CEF-PSI) in the rice leaves which suffered from photosystem II (PSII) photoinhibition. High-light (HL) treatment [2000 μmol photon m-2 s-1 at 0% carbon dioxide (CO2), 2% oxygen (O2) and 25°C] of rice leaves decreased both the maximum quantum efficiency of PSII (Fv/Fm) and the light-dependent O2-evolution rate [V(O2)]. High-light treatment did not affect the relative electron flux in PSI [Φ(PSI) × PFD]. In non-treated leaves, increasing in the photon flux density (PFD) enhanced V(O2), Φ(PSI) × PFD and the ratio of oxidized P700 to total P700 [(P700+)/(P700)total]. Φ(PSI) × PFD continued to increase even after the saturation of V(O2) against PFD. These results suggested that the electrons not used for the major electron sink, photosynthetic carbon reduction-cycle, did turnover in PSI, that is, CEF-PSI functioned at a higher PFD. High-light treatments did not affect the activity of CEF-PSI and increased (P700+)/(P700)total in the lower PFDs, compared to non-treated leaves. The activity of CEF-PSI depends on the amount of oxidized PQ. Photoinhibition of PSII suppressed electron influx from PSII to photosynthetic linear electron transport. The enhanced (P700+)/(P700)total suggested the increase in the ratio of oxidized plastoquinone (PQ) to total PQ, which supported the activity of CEF-PSI in the photoinhibited leaves.
KW - Cyclic electron flow around PSI
KW - P700
KW - PSI
KW - Photoinhibition
KW - Rice
UR - http://www.scopus.com/inward/record.url?scp=79955412377&partnerID=8YFLogxK
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U2 - 10.1080/00380768.2011.553803
DO - 10.1080/00380768.2011.553803
M3 - Article
AN - SCOPUS:79955412377
VL - 57
SP - 105
EP - 113
JO - Soil Science and Plant Nutrition
JF - Soil Science and Plant Nutrition
SN - 0038-0768
IS - 1
ER -