An analytical model of non-photorespiratory CO2 release in the light and dark in leaves of C3 species based on stoichiometric flux balance
An analytical model of non-photorespiratory CO2 release in the light and dark in leaves of C3 species based on stoichiometric flux balance
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DOI：
10.1111/j.1365-3040.2010.02228.x
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发表时间：
2011-01-01
影响因子：
7.3
通讯作者：
Adams, Mark A.
中科院分区：
文献类型：
--
作者：
Buckley, Thomas N.;Adams, Mark A.
叶片呼吸在光照下继续，但速率降低。这种抑制是高度可变的，其机制知之甚少，部分原因是缺乏一个正式的模型，可以产生可检验的假设。通过求解ATP、NADH和NADPH的稳态供需方程，结合广泛使用的光合作用模型，推导出非光呼吸CO2释放的分析模型。我们使用这个模型来评估光抑制呼吸的原因。该模型与许多意见，包括高度可变的抑制在饱和光，更大的抑制在成熟的叶片，减少同化商（净CO2和O-2交换的比率）同时硝酸盐减少和角效应（离散变化的量子产量在低光）。该模型预测了在中到强光下，或与产生ATP和NADH的过程（如脂肪酸或萜类化合物合成）同时进行的非磷酸化途径的参与。呼吸抑制主要由光合腺苷酸平衡控制，尽管光呼吸NADH可能在亚饱和光下起作用。关键问题包括腺苷酸的精确昼夜变化和腺苷酸磷酸化的ATP：2 e-比率。我们的模型可以专注于实验研究，是迈向完全基于过程的CO2交换模型的一步。
Leaf respiration continues in the light but at a reduced rate. This inhibition is highly variable, and the mechanisms are poorly known, partly due to the lack of a formal model that can generate testable hypotheses. We derived an analytical model for non-photorespiratory CO2 release by solving steady-state supply/demand equations for ATP, NADH and NADPH, coupled to a widely used photosynthesis model. We used this model to evaluate causes for suppression of respiration by light. The model agrees with many observations, including highly variable suppression at saturating light, greater suppression in mature leaves, reduced assimilatory quotient (ratio of net CO2 and O-2 exchange) concurrent with nitrate reduction and a Kok effect (discrete change in quantum yield at low light). The model predicts engagement of non-phosphorylating pathways at moderate to high light, or concurrent with processes that yield ATP and NADH, such as fatty acid or terpenoid synthesis. Suppression of respiration is governed largely by photosynthetic adenylate balance, although photorespiratory NADH may contribute at sub-saturating light. Key questions include the precise diel variation of anabolism and the ATP : 2e- ratio for photophosphorylation. Our model can focus experimental research and is a step towards a fully process-based model of CO2 exchange.