Global Change and Photosynthesis Research Unit, US Department of Agriculture Agricultural Research Service (USDA/ARS), Urbana, Illinois 61801; email:
Carl R. Woese Institute for Genomic Biology and.
Annu Rev Plant Biol. 2016 Apr 29;67:107-29. doi: 10.1146/annurev-arplant-043015-111709. Epub 2016 Feb 8.
Photorespiration is essential for C3 plants but operates at the massive expense of fixed carbon dioxide and energy. Photorespiration is initiated when the initial enzyme of photosynthesis, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), reacts with oxygen instead of carbon dioxide and produces a toxic compound that is then recycled by photorespiration. Photorespiration can be modeled at the canopy and regional scales to determine its cost under current and future atmospheres. A regional-scale model reveals that photorespiration currently decreases US soybean and wheat yields by 36% and 20%, respectively, and a 5% decrease in the losses due to photorespiration would be worth approximately $500 million annually in the United States. Furthermore, photorespiration will continue to impact yield under future climates despite increases in carbon dioxide, with models suggesting a 12-55% improvement in gross photosynthesis in the absence of photorespiration, even under climate change scenarios predicting the largest increases in atmospheric carbon dioxide concentration. Although photorespiration is tied to other important metabolic functions, the benefit of improving its efficiency appears to outweigh any potential secondary disadvantages.
光合作用是 C3 植物必不可少的，但它会以大量固定二氧化碳和能量为代价。当光合作用的初始酶——核酮糖-1,5-二磷酸羧化酶/加氧酶（Rubisco）与氧气而不是二氧化碳反应时，就会引发光合作用。然后通过光合作用再循环利用产生的有毒化合物。可以在冠层和区域尺度上对光合作用进行建模，以确定其在当前和未来大气条件下的成本。区域尺度模型表明，光合作用目前分别使美国大豆和小麦的产量减少了 36%和 20%，如果减少 5%的光合作用损失，美国每年将节省约 5 亿美元。此外，尽管大气二氧化碳浓度增加，但光合作用仍将继续影响未来气候下的产量，模型表明，即使在预测大气二氧化碳浓度增加最大的气候变化情景下，没有光合作用，总光合作用也将提高 12-55%。尽管光合作用与其他重要的代谢功能有关，但提高其效率的好处似乎超过了任何潜在的次要劣势。
