Arbuscular mycorrhizal fungal colonization of Glycyrrhiza glabra roots enhances plant biomass,phosphorus uptake and concentration of root secondary metabolites

Arbuscular mycorrhizal （AM） fungi penetrate the cortical cells of the roots of vascular plants, and are widely distributed in soil. The formation of these symbiotic bodies accelerates the absorption and utilization of min- eral elements, enhances plant resistance to stress, boosts the growth of plants, and increases the survival rate of transplanted seedlings. We studied the effects of various arbuscular mycorrhizae fungi on the growth and devel- opment of licorice （Glycyrrhiza glabra）. Several species of AM, such as Glomus mosseae, Glomus intraradices, and a mixture of fungi （G. mosseae, G intraradices, G. cladoideum, G microagregatum, G caledonium and G. etunica- tum） were used in our study. Licorice growth rates were determined by measuring the colonization rate of the plants by the fungi, plant dry biomass, phosphorus concentration and concentration of secondary metabolites. We estab- lished two cloned strains of licorice, clone 3 （C3） and clone 6 （C6） to exclude the effect of genotypic variations. Our results showed that the AM fungi could in fact increase the leaf and root biomass, as well as the phosphorus con- centration in each clone. Furthermore, AM fungi significantly increased the yield of certain secondary metabolites in clone 3. Our study clearly demonstrated that AM fungi play an important role in the enhancement of growth and development of licorice plants. There was also a significant improvement in the secondary metabolite content and yield of medicinal compounds from the roots.