Abstract:To understand the effect of arbuscular mycorrhizal (AM) fungi on secondary metabolism in root and root exudates and plant growth, Citrus reticulata was inoculated by AM fungus Glomus epigaeum, the phenolic, antioxidant enzyme and growth of C. reticulata were studied. After six months cultured in greenhouse, the concentrations of phenolic acids in C. reticulata inoculated with AM fungus significantly increased. However, the components of phenolic acid were different in root and root exudates, the contents of protocatechunic acid and syringic acid in roots was 29.98 and 18.32 μg/g, which were 4.58 and 2.26 times higher than those in control, respectively. The contents of coumaric acid, benzoic acid and phloridzin were 0.36, 6.04 and 12.32 μg/g, respectively, which were 1.71, 1.94 and 1.25 times higher than those in control. Whereas vanillin was only detected in uninoculated roots. The enzyme activities of phenylalnine ammonia-lyase, polyphenol oxidase and peroxidase in C. reticulata inoculated with AM fungus were 38.36, 0.51 and 28.62 U/(g·min), respectively, which were 1.99, 2.83 and 3.10 times higher than those in control. In addition, the height, stem diameter and leaf number of C. reticulata inoculated with arbuscular mycorrhizal fungi also significantly increased. It was suggested that AM colonization could significantly affected the growth and secondary metabolites in C. reticulata.