Dark recovery of the Chl a fluorescence transient (OJIP) after light adaptation:: The qT-component of non-photochemical quenching is related to an activated photosystem I acceptor side
Dark recovery of the Chl a fluorescence transient (OJIP) after light adaptation:: The qT-component of non-photochemical quenching is related to an activated photosystem I acceptor side
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DOI：
10.1016/j.bbabio.2006.04.019
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发表时间：
2006-07-01
影响因子：
4.3
通讯作者：
Strasser, Reto J.
中科院分区：
文献类型：
--
作者：
Schansker, Gert;Toth, Szilvia Z.;Strasser, Reto J.
研究了Chl - a荧光瞬态（OJIP）在光适应15 min后的暗恢复动力学，并借助同时测量的820 nm透射率进行了解释。OJIP瞬态形状变化的动力学与非光化学猝灭的qE和qT组分的动力学有关。qE的暗弛豫与荧光产率的普遍增加相一致。光适应导致ojip瞬态的ip相（20 ~ 200 ms）消失。在20-200 ms的时间范围内，qt与ip相的恢复以及P700（+）和氧化质体青素的再还原的恢复相关，这是由820 nm透射测量得出的。在这些观察的基础上，qT被解释为表征铁氧还蛋白- nadp(+)-还原酶（FNR）的失活动力学。FNR的活化状态通过对电子流的影响来影响荧光产率。因此qT是光化学猝灭的一种形式。将探针脉冲的光强从1800增加到15000 μ mol光子m(-2) s(-1)，对结果没有质的改变。所提出的观察结果表明，在适应光的叶片中，不可能用强光脉冲“关闭”所有的反应中心。这支持了一个假设，即除了Q(A)外，还需要位于光系统II受体侧的第二个荧光产率调制器（例如，占用Q(B)-位点）来解释这些结果。此外，我们的一些研究结果表明，豌豆叶片状态2到1的转变可能有助于qi期。(c) 2006 Elsevier B.V.版权所有
The dark recovery kinetics of the Chl a fluorescence transient (OJIP) after 15 min light adaptation were studied and interpreted with the help of simultaneously measured 820 nm transmission. The kinetics of the changes in the shape of the OJIP transient were related to the kinetics of the qE and qT components of non-photochemical quenching. The dark-relaxation of the qE coincided with a general increase of the fluorescence yield. Light adaptation caused the disappearance of the IP-phase (20-200 ms) of the OJIP-transient. The qTcorrelated with the recovery of the IP-phase and with a recovery of the re-reduction of P700(+) and oxidized plastocyanin in the 20-200 ms time-range as derived from 820 nm transmission measurements. On the basis of these observations, the qT is interpreted to represent the inactivation kinetics of ferredoxin-NADP(+)-reductase (FNR). The activation state of FNR affects the fluorescence yield via its effect on the electron flow. The qT therefore represents a form of photochemical quenching. Increasing the light intensity of the probe pulse from 1800 to 15000 mu mol photons m(-2) s(-1) did not qualitatively change the results. The presented observations imply that in light-adapted leaves, it is not possible to 'close' all reaction centers with a strong light pulse. This supports the hypothesis that in addition to Q(A) a second modulator of the fluorescence yield located on the acceptor side of photosystem II (e.g., the occupancy of the Q(B)-site) is needed to explain these results. Besides, some of our results indicate that in pea leaves state 2 to 1 transitions may contribute to the qI-phase. (c) 2006 Elsevier B.V. All rights reserved.