On the analysis of non-photochemical chlorophyll fluorescence quenching curves I. Theoretical considerations
On the analysis of non-photochemical chlorophyll fluorescence quenching curves I. Theoretical considerations
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DOI：
10.1016/j.bbabio.2013.02.011
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发表时间：
2013-06-01
影响因子：
4.3
通讯作者：
Jahns, Peter
中科院分区：
文献类型：
--
作者：
Holzwarth, Alfred R.;Lenk, Dagmar;Jahns, Peter
非光化学猝灭（NPQ）保护光合生物免受强光的光损伤。表征NPQ的关键测量参数之一是强光诱导的叶绿素荧光下降。最初测量的数据是最大荧光（Fm’）信号作为光化照明时间（Fm’(t)）的函数。通常将这些原始数据转换为所谓的Stem-Volmer猝灭函数NPQ(SV)(t)，然后根据各种NPQ机制和动力学对其进行分析和解释。然而，对这一分析的解释基本上取决于NPQ确实遵循Stem-Volmer关系的假设。在这里，我们质疑这种普遍假设的关系，令人惊讶的是，这种关系从未得到证实。我们通过淬火数据的模拟证明，特别是将时间相关的淬火曲线（如Fm'(t)）转换为NPQ(SV)(t)在其影响方面（数学上）不是“无害的”。它扭曲了最初测量函数Fm'(t)中包含的动力学淬火信息，导致淬火时间依赖性的严重（通常是s型）扭曲，并对揭示潜在的淬火机制及其对淬火动力学的贡献的能力产生负面影响。我们得出结论，NPQ(SV)(t)空间中常用的随时间变化的NPQ分析应该重新考虑。首先，这种普遍的做法没有合理的理论依据。其次，在直接分析和解释原始测量的Fm'(t)数据时，不会发生任何信息损失。因此，当试图将猝灭数据与其他与猝灭相关的生化信息关联起来时，对Fm'(t)数据的分析具有更高的潜力，可以提供正确的机制答案。(C) 2013 Elsevier B.V.版权所有
Non-photochemical quenching (NPQ) protects photosynthetic organisms against photodamage by high light. One of the key measuring parameters for characterizing NPQ is the high-light induced decrease in chlorophyll fluorescence. The originally measured data are maximal fluorescence (Fm') signals as a function of actinic illumination time (Fm'(t)). Usually these original data are converted into the so-called Stem-Volmer quenching function, NPQ(SV)(t), which is then analyzed and interpreted in terms of various NPQ mechanisms and kinetics. However, the interpretation of this analysis essentially depends on the assumption that NPQ follows indeed a Stem-Volmer relationship. Here, we question this commonly assumed relationship, which surprisingly has never been proven. We demonstrate by simulation of quenching data that particularly the conversion of time-dependent quenching curves like Fm'(t) into NPQ(SV)(t) is (mathematically) not "innocent" in terms of its effects. It distorts the kinetic quenching information contained in the originally measured function Fm'(t), leading to a severe (often sigmoidal) distortion of the time-dependence of quenching and has negative impact on the ability to uncover the underlying quenching mechanisms and their contribution to the quenching kinetics. We conclude that the commonly applied analysis of time-dependent NPQ in NPQ(SV)(t) space should be reconsidered. First, there exists no sound theoretical basis for this common practice. Second, there occurs no loss of information whatsoever when analyzing and interpreting the originally measured Fm'(t) data directly. Consequently, the analysis of Fm'(t) data has a much higher potential to provide correct mechanistic answers when trying to correlate quenching data with other biochemical information related to quenching. (C) 2013 Elsevier B.V. All rights reserved.