Nitrogen transport in the orchid mycorrhizal symbiosis – further evidence for a mutualistic association

Mycorrhizas are symbioses integral to the health of plant-based ecosystems (Smith & Read, 2008). In a typical mycorrhizal association, fungi in, or on, plant roots pass soil-acquired inorganic nutrients and water to the plant host. In return, the host transfers excess photosynthate to the fungus