Abstract: The effects of arbuscular mycorrhizal（AM）fungi on antioxidant enzyme activity in peony （Paeonia suffruticosa）seedlings inoculated with Glomus mosseae or G. versiforme，and grown under the condition of four levels of artificial seawater（0，8%，16% and 24%）were studied. The experimental results showed that mycorrhizal dependence（MD）of peony seedlings in treatment with 8% salt was the highest，and MD of peony seedlings inoculated with G. mosseae was 172% significantly higher than that with G. versiforme（150%）. Thirty days after salt stress with 8% salt concentration，the dry weight，leaf relative water content，leaf superoxide dismutase activity，peroxidase activity，peroxidase activity，catalase activity of peony seedlings inoculated with G. mosseae and G. versiforme were 0.51 g and 0.45 g，80.5% and 78.5%，4.72 and 4.46 U • g-1，60.3 and 57.4 U • min-1 • g-1，51.3 and 47.2 U • min-1 • g-1，respectively，and significantly higher than control. The similar trends were given under 16% and 24% salt concentration. As time prolonged under salt stress condition，SOD and CAT activities increased first but decreased afterwards，while POD activities showed an increasing trend. AM fungi could increase activities of the antioxidant enzyme system. Thus，the salt tolerance of mycorrhizal seedlings was enhanced. Glomus mosseae was the superior.

Key words: Paeonia suffruticosa, arbuscular mycorrhizal fungi, Glomus mosseae, G. versiforme, antioxidant enzyme, salt tolerance