A pyrenoid-based carbon-concentrating mechanism is present in terrestrial bryophytes of the class Anthocerotae
A pyrenoid-based carbon-concentrating mechanism is present in terrestrial bryophytes of the class Anthocerotae
复制标题
花角藻类陆生苔藓植物中存在基于核糖核的碳浓缩机制
作者：
Elizabeth C. Smith;H. Griffiths
人们普遍认为，短尾轮虫的碳同化完全是基于传统的C3光合途径。生物化学的CO2浓缩机制（C4或景天科酸代谢）的发生，在过去的2000万至1亿年中已经在植物中发展起来，已经从有机物质的碳同位素组成（δ 13 C）的研究中排除了britonites。相反，蓝细菌和许多藻类通过生物物理的CO2浓缩机制显示出溶解无机碳的积极积累，这也在某些地衣中的光合生物伙伴中发现。蛋白核，叶绿体内的颗粒状颗粒的存在下，已与CO2浓缩机制活动在绿色藻类和地衣，我们现在表明，这样的机制是明确相关的发生在属于类的Anthocerotae的bratites的蛋白核。这些观察结果具有显着的进化意义的陆地光合作用的发展过程中的殖民地的土地，提出了有趣的问题，为什么蛋白核为基础的CO2浓缩机制没有坚持在陆地环境。
It has been widely accepted that carbon assimilation in bryophytes is exclusively based on the conventional C3 photosynthetic pathway. The occurrence of biochemical CO2-concentrating mechanisms (C4 or Crassulacean acid metabolism), which have developed in plants in the last 20–100 million years, has been discounted for bryophytes from studies of the carbon isotope composition (δ13C) of organic material. In contrast cyanobacteria and many algae show active accumulation of dissolved inorganic carbon via biophysical CO2-concentrating mechanisms which are also found in the photobiont partners in certain lichens. The presence of a pyrenoid, a granular particle within the chloroplast, has been linked with CO2-concentrating mechanism activity in green algae and lichens and we now show that such a mechanism is categorically associated with the occurrence of a pyrenoid in bryophytes belonging to the class of Anthocerotae. These observations have significant evolutionary implications for the development of terrestrial photosynthesis during the colonisation of the land, raising the intriguing question of why the pyrenoid-based CO2-concentrating mechanism did not persist in the terrestrial environment.