It is well known that far-red light (FR; >700 nm) drives PSI photochemistry, but its effect on photosynthetic performance has received little attention. In this study, the effects of the addition of FR to red fluctuating light (FL) have on photosynthesis were examined in the leaves of Arabidopsis thaliana. Light-activated leaves were illuminated with FL [alternating high light/low light (HL/LL) at 800/30 μmol m-2 s-1] for 10-15 min without or with FR at intensities that reflected natural conditions. The CO2 assimilation rates upon the transition from HL to LL were significantly greater with FR than without FR. The enhancement of photosynthesis by FR was small under the steady-state conditions and in the HL phases of FL. Proton conductivity through the thylakoid membrane (gH+) in the LL phases of FL, estimated from the dark relaxation kinetics of the electrochromic absorbance shift, was greater with FR than without FR. The relaxation of non-photochemical quenching (NPQ) in the PSII antenna system and the increase in PSII photochemistry in the LL phases accelerated in the presence of FR. Similar FR-effects in FL were confirmed in typical sun and shade plants. On the basis of these results, we concluded that FR exerted beneficial effects on photosynthesis in FL by exciting PSI and accelerating NPQ relaxation and PSII-yield increase. This was probably because of the increased gH+, which would reflect faster ΔpH dissipation and ATP synthesis.

中文翻译：

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远红光可在脉动光的弱光阶段加速光合作用。

众所周知，远红光（FR;> 700 nm）可以驱动PSI光化学，但是其对光合作用性能的影响却很少受到关注。在这项研究中，研究了在拟南芥叶片中向红色脉动光（FL）中添加FR对光合作用的影响。用FL [在800/30μmolm-2 s-1的高光/低光（HL / LL）交替照明]光照10到15分钟，而无或用FR反射自然条件下的强度。从FR到LL过渡时，有FR时的CO2同化率显着高于没有FR时。在稳态条件下和FL的HL期，FR对光合作用的促进作用很小。在FL的LL相中穿过类囊体膜（gH +）的质子电导率，根据电致变色吸收位移的暗弛豫动力学估算的结果，FR比无FR时更大。在存在FR的情况下，PSII天线系统中非光化学猝灭（NPQ）的弛豫和LL相中PSII光化学的增加加速了。在典型的日光和阴凉植物中，也证实了FL中类似的FR效应。根据这些结果，我们得出结论，FR通过激发PSI并加速NPQ弛豫和PSII产量的增加，对FL的光合作用产生了有益的影响。这可能是因为gH +增加，这将反映出更快的ΔpH耗散和ATP合成。在存在FR的情况下，PSII天线系统中非光化学猝灭（NPQ）的弛豫和LL相中PSII光化学的增加加速了。在典型的日光和阴凉植物中，也证实了FL中类似的FR效应。根据这些结果，我们得出结论，FR通过激发PSI并加速NPQ弛豫和PSII产量的增加，对FL的光合作用产生了有益的影响。这可能是因为gH +增加，这将反映出更快的ΔpH耗散和ATP合成。在存在FR的情况下，PSII天线系统中非光化学猝灭（NPQ）的弛豫和LL相中PSII光化学的增加加速了。在典型的日光和阴凉植物中，也证实了FL中类似的FR效应。根据这些结果，我们得出结论，FR通过激发PSI并加速NPQ弛豫和PSII产量的增加，对FL的光合作用产生了有益的影响。这可能是因为gH +增加，这将反映出更快的ΔpH耗散和ATP合成。