通过中间态电子载体在杜氏盐藻中控制氧释放的错误。

Control of misses in oxygen evolution by the oxido-reduction state of plastoquinone in Dunaliella tertiolecta.

机构信息

Centre de Recherche en photobiophysique, Université du Quebec à Trois-Rivières, C.P. 500, G9A 5H7, Trois-Rivières, Qc., Canada.

出版信息

Photosynth Res. 1990 Feb;23(2):213-21. doi: 10.1007/BF00035012.

DOI:10.1007/BF00035012

PMID:24421063

Abstract

The way misses happen in oxygen evolution is subject to debate (Govindjee et al. 1985). We recently observed a linear lowering of the miss probability with the flash number (Meunier and Popovic 1989). Therefore, we investigated in Dunaliella tertiolecta the link between the average miss probability and the redox state of plastoquinone after n flashes. The effect of flashes was to oxidize the plastoquinone pool; we found that the oxidation of plastoquinone highly correlated (linear regression: R (2)=0.996) with the lowering of the miss probability. The flash frequency was found to affect both the miss probability and the redox state of plastoquinone. When pre-flashes were given using a high flash frequency (10 Hz), the plastoquinone pool was oxidized and misses were low; however, if long dark intervals between flashes were used, the oxidizing effect of flashes was lost and the misses were high. We could not explain our results by assuming equal misses over all S-states; but unequal misses, caused by deactivations, were coherent with our results. We deduced that chlororespiration was responsible for the reduction of plastoquinone in the dark interval between flashes. We compared oxygen evolution with and without benzoquinone, using a low flash frequency (0.5 Hz) for maximum misses. Benzoquinone lowered the misses from 34% to 3%, and raised the amplitude of oxygen evolution by more than a factor of two (2). From this we deduced that the charge carrier "C" postulated to explain misses (Lavorel and Maison-Peteri 1983) did not account for more than 3% of miss probability in Dunaliella tertiolecta. These results indicate that the misses in oxygen evolution are controlled by the redox state of plastoquinone, through deactivations.

摘要

在氧释放过程中， misses 的发生方式存在争议（Govindjee 等人，1985 年）。我们最近观察到 misses 概率随闪光次数呈线性降低（Meunier 和 Popovic，1989 年）。因此，我们在杜氏盐藻中研究了在 n 次闪光后，平均 misses 概率与质体醌氧化还原状态之间的联系。闪光的作用是氧化质体醌池；我们发现质体醌的氧化与 misses 概率的降低高度相关（线性回归：R 2=0.996）。闪光频率被发现同时影响 misses 概率和质体醌的氧化还原状态。当使用高闪光频率（10 Hz）进行预闪光时，质体醌池被氧化， misses 概率较低；然而，如果在闪光之间使用长的暗间隔，则闪光的氧化作用会丢失， misses 概率会较高。我们不能通过假设所有 S 态的 misses 概率相等来解释我们的结果；但是，由于失活引起的不等 misses 与我们的结果是一致的。我们推断，在闪光之间的黑暗间隔中，氯呼吸负责质体醌的还原。我们比较了有和没有苯醌的氧气释放，使用低闪光频率（0.5 Hz）以获得最大 misses。苯醌将 misses 从 34%降低到 3%，并将氧气释放的幅度提高了两倍以上（2）。由此我们推断，为了解释 misses 而假设的电荷载体“C”（Lavorel 和 Maison-Peteri，1983 年）在杜氏盐藻中不超过 misses 概率的 3%。这些结果表明，氧释放中的 misses 是通过失活来控制的，其控制因素是质体醌的氧化还原状态。