Porcar-Castell Albert, Bäck Jaana, Juurola Eija, Hari Pertti
Department of Forest Ecology, University of Helsinki, Latokartanonkaari 7, PO Box 27, 00014 Helsinki, Finland.
Funct Plant Biol. 2006 Mar;33(3):229-239. doi: 10.1071/FP05133.
Several biochemical models of photosynthesis exist that consider the effects of the dynamic adjustment of enzymatic and stomatal processes on carbon assimilation under fluctuating light. However, the rate of electron transport through the light reactions is commonly modelled by means of an empirical equation, parameterised with data obtained at the steady state. A steady-state approach cannot capture the dynamic nature of the adjustment of the light reactions under fluctuating light. Here we present a dynamic model approach for photosystem II that considers the adjustments in the regulative non-photochemical processes. The model is initially derived to account for changes occurring at the seconds-to-minutes time-scale under field conditions, and is parameterised and tested with chlorophyll fluorescence data. Results derived from this model show good agreement with experimentally obtained photochemical and non-photochemical quantum yields, providing evidence for the effect that the dark reactions exert in the adjustment of the energy flows at the light reactions. Finally, we compare the traditional steady-state approach with our dynamic approach and find that the steady-state approach produces an underestimation of the modelled electron transport rate (ETR) under rapidly fluctuating light (1 s or less), whereas it produces overestimations under slower fluctuations of light (5 s or more).
存在几种光合作用的生化模型，这些模型考虑了在波动光照下酶促过程和气孔过程的动态调节对碳同化的影响。然而，通过光反应的电子传输速率通常通过一个经验方程来建模，该方程用在稳态下获得的数据进行参数化。稳态方法无法捕捉波动光照下光反应调节的动态性质。在这里，我们提出了一种用于光系统II的动态模型方法，该方法考虑了调节性非光化学过程中的调节。该模型最初是为了解释田间条件下秒到分钟时间尺度上发生的变化而推导出来的，并用叶绿素荧光数据进行了参数化和测试。从该模型得出的结果与实验获得的光化学和非光化学量子产率显示出良好的一致性，为暗反应在光反应能量流调节中所起的作用提供了证据。最后，我们将传统的稳态方法与我们的动态方法进行比较，发现稳态方法在快速波动光照（1秒或更短时间）下对模拟电子传输速率（ETR）产生低估，而在较慢的光照波动（5秒或更长时间）下产生高估。
