Arbuscular Mycorrhizal Fungi Regulate the Growth and Phyto-Active Compound of Salvia miltiorrhiza Seedlings

Roots and rhizomes of Salvia miltiorrhiza (S. miltiorrhiza) are widely used for the treatment of cardiovascular diseases. Arbuscular mycorrhizal fungi (AMFs) have been shown to enhance plant growth and increase secondary metabolites concentration in many plant species. However, effects of AMFs on S. miltiorrhiza have not been explored. A pot culture was designed as one control (non-AMF) treatment and four AMFs (G.m, Glomus mosseae; G.a, Glomus aggregatum; G.v, Glomus versiforme; G.i, Glomus intraradices) treatments were performed in order to evaluate the effects of AMFs on plant growth, as well as phyto-active compounds’ concentration of S. miltiorrhiza seedlings. Plants were harvested after 90 days: agronomic traits and concentration; and an accumulation of mineral elements, as well as phyto-active compounds were detected. All AMFs inoculated plants formed mycorrhizal structures, and an infection ratio; also, the intensity of inoculated roots was higher than 84.61% and 23.86%, respectively. Mycorrhizal dependency was above 144.62%. Seedlings with AMFs inoculation had significantly higher plant height, leather leaf length, top leaflet size, base leaflet length, taproot length, taproot diameter and biomass than those with non-AMF inoculation. In addition, inoculation with AMFs increased N, P, and K accumulation significantly, but barely had any effect on mineral elements’ concentrations. AMFs inoculation also significantly improved tanshinones concentrations and stimulation in order to accumulate salvianolic acid B. G.v and G.i were effective for seedlings growth; G.m and G.i were also effective for phyto-active compounds. In total, S. miltiorrhiza inoculation with AMFs had positive effects on growth and active components, especially inoculation with G.v