Growth and Nutrient Content of Trifoliate Orange Seedlings Influenced by Arbuscular Mycorrhizal Fungi Inoculation in Low Magnesium Soil

A pot experiment was conducted to examine the effects of arbuscular mycorrhizal fungi, Glomus versiforme, G. mosseae, and G. intraradices on growth and nutrition of trifoliate orange (Poncirus trifoliata) seedlings under magnesium (Mg)-nontreated and Mg-treated conditions. Whether treated with Mg or not, G. versiforme inoculation significantly enhanced the growth and concentrations of Mg, phosphorus, calcium, potassium, zinc, and copper in shoots or roots, and activities of acid phosphatase, catalase, invertase, and urease in rhizosphere soils. Additionally, there were higher levels of chlorophyll, proline, soluble sugar and protein in leaves, root viability, superoxide dismutase, peroxidase and catalase in leaves and roots, but lower malondialdehyde content in leaves and roots of mycorrhizal seedlings than non-mycorrhizal ones. Data demonstrated that G. versiforme-inoculated citrus seedlings exhibited higher levels of soil enzymes, osmoregulation, and antioxidant matters, leading to improvement of growth and nutrition of seedlings in low Mg soil.