Coral reefs’ high productivity has been attributed mainly to photosymbioses between the coral animal and algae of the family Symbiodiniaceae, with recognition that the host can increase algal photosynthesis by concentrating nutrients and enhancing the efficiency of light absorption. Here, we propose that an additional effect, consumption of carbohydrate by the host, may also enhance algal photosynthesis. We examine evidence from symbiosis between terrestrial plants and root fungi that indicates a link between carbohydrate consumption by the symbiotic partner and photosynthetic upregulation in the plant system. In addition, we review evidence from free‐living algae manipulated to exude carbohydrate into the external medium, which was associated with strong upregulation of photosynthetic capacity. We offer suggestions on how host‐induced carbohydrate release may increase photosynthesis rates in the symbionts in the intact photosymbiosis and how this relationship evolved.

中文翻译：

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珊瑚礁的生产力和多样性—来自宿主对碳水化合物的需求，促进了光合作用，从而做出了贡献

珊瑚礁的高生产力主要归因于共生动物科的珊瑚动物和藻类之间的光合酶，并认识到宿主可以通过集中营养和提高光吸收效率来提高藻类的光合作用。在这里，我们提出一种额外的作用，即宿主吸收碳水化合物，也可以增强藻类的光合作用。我们研究了陆生植物与根真菌之间共生的证据，这些证据表明共生伙伴的碳水化合物消耗与植物系统中光合作用的上调之间存在联系。此外，我们回顾了来自操纵自由藻类以将碳水化合物渗入外部介质的证据，这与光合能力的强烈上调有关。