FIGURE 4.

(A) Pathways by which nitrogen is assimilated and transformed within extraradical mycelium (ERM) of arbuscular mycorrhizal fungai (AMF) before export to host plants (Govindarajulu et al., 2005; Tian et al., 2010). (B) Pathways by which assimilated nitrogen is transferred from intraradical mycelium (IRM) to plant root cells. Solid arrows indicate known pathways. Dashed arrows indicate potential nitrogen assimilation pathway in orchid mycorrhizas (Chen et al., 2018; Cruz et al., 2007; Fochi et al., 2017; Govindarajulu et al., 2005; Jin et al., 2012)