Common mycelium network of mycorrhizas alters plant biomass and soil properties between trifoliate orange seedlings.

Common mycelium networks (CMNs) of arbuscular mycorrhizas link neighbour plants and thus exhibit important roles in underground communication of substances between plants. In this study, a two-compartmented rootbox separated by 37-mu m (mycelium, but not root, can pass through the size mesh) or 0.45-mu m (both mycelium and root can't pass through the size mesh) mesh was used, where one compartment was inoculated with Paraglomus occultum. We confirmed whether CMNs establish between trifoliate orange seedlings and have the roles in improving both plant growth and soil properties in receptor plant (the plant inoculated without mycorrhizal fungi but infected by mycorrhizal mycelium of another inoculated plant). A CMN was formed between trifoliate orange seedlings under separation of 37-mu m but not 0.45-mu m mesh, resulting in a moderate root colonization of receptor plant. The mycorrhizal inoculation significantly increased leaf, stem, and root fresh weight and rhizospheric three glomalin-related soil protein (GRSP) concentrations, soil organic carbon, and mean weight diameter in the donor plant (the inoculated plant with mycorrhizal fungi). The CMN under 37-mu m mesh condition had significantly positive effects on the above growth and soil properties in the receptor plant. Under 0.45-mu m mesh, the AMF inoculation in donor plant considerably inhibited biomass production of receptor plant, but increased easily-extractable GRSP, total GRSP, soil organic carbon, and mean weight diameter in receptor plant. It suggested that AMF inoculation and the subsequent CMN establishment would benefit improvement of plant growth and soil aggregation and fertility in donor and receptor plant.