Rising CO2 concentrations and their effects on plant productivity present challenging issues. Effects on the photosynthesis/photorespiration balance and changes in primary metabolism are known, caused by the competitive interaction of CO2 and O2 at the active site of ribulose-1,5-bisphosphate carboxylase/oxygenase. However, impacts on stress resistance are less clear. Reactive oxygen species are key players in biotic and abiotic stress responses, but there is no consensus on whether elevated CO2 constitutes a stress. Although high CO2 increases yield in C3 plants, it can also increase cellular oxidation and activate phytohormone defense pathways. Reduction-oxidation processes play key roles in acclimation to high CO2, with specific enzymes acting in compartment-specific signaling. Traditionally, acclimation to high CO2 has been considered in terms of altered carbon gain, but emerging evidence suggests that CO2 is a signal as well as a substrate. Some CO2 effects on defense are likely mediated independently of primary metabolism. Nonetheless, primary photosynthetic metabolism is highly integrated with defense and stress signaling pathways, meaning that plants will be able to acclimate to the changing environment over the coming decades.

中文翻译：

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高二氧化碳世界中的氧化还原稳态和信号传导

不断上升的二氧化碳浓度及其对植物生产力的影响提出了具有挑战性的问题。已知对光合作用/光呼吸平衡和初级代谢变化的影响是由 CO2 和 O2 在 1,5-二磷酸核酮糖羧化酶/加氧酶活性位点的竞争性相互作用引起的。然而，对抗压性的影响不太清楚。活性氧是生物和非生物应激反应的关键参与者，但对于 CO2 升高是否构成应激尚未达成共识。虽然高 CO2 增加了 C3 植物的产量，但它也可以增加细胞氧化并激活植物激素防御途径。还原氧化过程在适应高 CO2 中起着关键作用，特定的酶在特定于隔室的信号传导中起作用。传统上，从改变碳增益的角度考虑适应高二氧化碳，但新出现的证据表明，二氧化碳是一种信号，也是一种底物。一些 CO2 对防御的影响可能独立于初级代谢而介导。尽管如此，初级光合代谢与防御和压力信号通路高度整合，这意味着植物将能够在未来几十年适应不断变化的环境。