Effects of arbuscular mycorrhizal fungi on growth and Na+ accumulation of Suaeda glauca (Bunge) grown in salinized wetland soils

Abstract

Salinization inhibits the vegetation restoration of wetland soils due to its adverse effects on plant growth and development. Research findings show that arbuscular mycorrhizal (AM) fungi can reduce the negative effects of salinization and facilitate the revegetation of salinized dryland soils. The application of halophytes in the vegetation restoration of salinized soils has received increasing attention. However, limited studies are available concerning whether AM fungi are effective in improving wetland halophyte performance in salinized wetland soils. A pot experiment was conducted to quantitatively analyze the potential role of 3 AM fungal species (Funneliformis mosseae, Rhizophagus intraradices, and Diversispora tortuosa) on the growth, nutritional status, salt uptake, ionic homeostasis, osmotic substance synthesis, and antioxidant enzyme activities of Suaeda glauca (Bunge) grown in salinized wetland soils. The rhizosphere soil properties (i.e., extractable glomalin protein content and pH) were also analyzed after harvest. The results showed that mycorrhizal symbiosis significantly increased the S. glauca biomass and shoot Na+ accumulation by 28.6%–73.8% and 28.1%–135%, respectively, with D. tortuosa being more effective than F. mosseae or R. intraradices. Mycorrhizal symbiosis substantially increased the nutrient uptake, soluble protein and proline content, and SOD and CAT activity while significantly decreasing the MDA content, effects that can help S. glauca resist and adapt to salinized conditions. Counterintuitively, mycorrhizal symbiosis had marginal (even significantly negative) effects on the mitigation of the ionic ratios (e.g., K+/Na+ and P/Na+), which may be attributed to the increase in Na+ accumulation and translocation from roots to shoots. Mycorrhizal symbiosis significantly increased the rhizosphere soil TEG content and decreased the soil pH. These results enhance our understanding of the functional importance of AM fungi in improving halophyte performance and suggest the potential use of AM fungi in the revegetation of salinized wetland soils.