Protection of photosystem II against damage from excess light by nonphotochemical quenching (NPQ) includes responses on a wide range of timescales. The onset of the various phases of NPQ overlap in time making it difficult to discern if they influence each other or involve different photophysical mechanisms. To unravel the complex relationship of the known actors in NPQ, we perform fluorescence lifetime snapshot measurements throughout multiple cycles of alternating 2 min periods of high light and darkness. By comparing the data with an empirically based mathematical model that describes both fast and slow quenching responses, we suggest that the rapidly reversible quenching response depends on the state of the slower response. By studying a series of Arabidopsis thaliana mutants, we find that removing zeaxanthin (Zea) or enhancing PsbS concentration, for example, influences the amplitudes of the slow quenching induction and recovery, but not the timescales. The plants’ immediate response to high light appears independent of the illumination history, while PsbS and Zea have distinct roles in both quenching and recovery. We further identify two parameters in our model that predominately influence the recovery amplitude and propose that our approach may prove useful for screening new mutants or overexpressors with enhanced biomass yields under field conditions.

中文翻译：

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PsbS 和叶黄素在波动光下拟南芥非光化学猝灭调控中的复杂作用

通过非光化学猝灭 (NPQ) 保护光系统 II 免受过量光的损害包括在广泛的时间尺度上的响应。NPQ 各个阶段的开始在时间上重叠，因此很难辨别它们是否相互影响或涉及不同的光物理机制。为了解开 NPQ 中已知参与者的复杂关系，我们在高光和黑暗交替的 2 分钟周期的多个周期中执行荧光寿命快照测量。通过将数据与描述快速和慢速淬火响应的基于经验的数学模型进行比较，我们建议快速可逆的淬火响应取决于较慢响应的状态。通过研究一系列拟南芥例如，我们发现去除玉米黄质 (Zea) 或提高 PsbS 浓度会影响缓慢淬火诱导和恢复的幅度，但不会影响时间尺度。植物对强光的直接反应似乎与光照历史无关，而 PsbS 和 Zea 在猝灭和恢复方面具有不同的作用。我们进一步确定了我们模型中主要影响恢复幅度的两个参数，并提出我们的方法可能证明对筛选在田间条件下具有增强的生物量产量的新突变体或过表达体有用。