Research Department of Genetics, Evolution and Environment, Darwin Building, University College London, Gower Street, London WC1E 6BT, UK.
School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.
Trends Plant Sci. 2019 Nov;24(11):1022-1031. doi: 10.1016/j.tplants.2019.07.007. Epub 2019 Aug 22.
Cyanobacteria produced the oxygen that began to accumulate on Earth 2.5 billion years ago, at the dawn of the Proterozoic Eon. By 2.4 billion years ago, the Great Oxidation Event (GOE) marked the onset of an atmosphere containing oxygen. The oxygen content of the atmosphere then remained low for almost 2 billion years. Why? Nitrogenase, the sole nitrogen-fixing enzyme on Earth, controls the entry of molecular nitrogen into the biosphere. Nitrogenase is inhibited in air containing more than 2% oxygen: the concentration of oxygen in the Proterozoic atmosphere. We propose that oxygen inhibition of nitrogenase limited Proterozoic global primary production. Oxygen levels increased when upright terrestrial plants isolated nitrogen fixation in soil from photosynthetic oxygen production in shoots and leaves.
蓝藻产生了氧气，这些氧气在 25 亿年前的元古代早期开始在地球上积累。到 24 亿年前，大氧化事件 (GOE) 标志着含氧大气的开始。大气中的含氧量随后在近 20 亿年内保持较低水平。为什么呢？地球上唯一的固氮酶氮酶控制着分子氮进入生物圈。氮酶在含氧量超过 2%的空气中受到抑制：元古代大气中的氧浓度。我们提出，氮酶的氧抑制限制了元古代全球的初级生产力。当直立的陆地植物将土壤中的固氮作用与茎和叶中的光合作用产生的氧气隔离开来时，氧气水平就会升高。
