Cyclic electron flow around PSI functions in the photoinhibited rice leaves
Cyclic electron flow around PSI functions in the photoinhibited rice leaves
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DOI：
10.1080/00380768.2011.553803
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发表时间：
2011-02
影响因子：
2
通讯作者：
S. Kubo;T. Masumura;Yuhi Saito;H. Fukayama;Yuji Suzuki;T. Sugimoto;A. Makino;K. Amako;C. Miyake
中科院分区：
文献类型：
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作者：
S. Kubo;T. Masumura;Yuhi Saito;H. Fukayama;Yuji Suzuki;T. Sugimoto;A. Makino;K. Amako;C. Miyake
研究了光系统II（PSII）光抑制水稻叶片中光系统I周围循环电子流（CEF-PSI）的调控机制。强光（HL）处理（2000 µmol photon m-2 s-1，0% CO2，2% O2，25°C）降低了水稻叶片PSII的最大量子效率（Fv/Fm）和光依赖的O2释放速率[V（O2）]。强光处理不影响PSI [Φ（PSI）× PFD]的相对电子通量。在未处理的叶片中，增加光通量密度（PFD）使V（O2）、Φ（PSI）× PFD和氧化态P700与总P700的比值[（P700+）/（P700）total]增加。即使在V（O2）对PFD饱和后，Φ（PSI）× PFD仍继续增加。这些结果表明，电子不用于主要的电子库，光合碳还原循环，在PSI，即CEF-PSI功能在一个较高的PFD。强光处理不影响CEF-PSI的活性，但提高了下部PFDs的（P700+）/（P700）总量。CEF-PSI的活性取决于氧化PQ的量。光抑制抑制PSII抑制电子内流从PSII光合线性电子传递。（P700+）/（P700）总量的增加表明氧化质体醌（PQ）占总PQ的比例增加，这支持了光抑制叶片中CEF-PSI的活性。
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.