The effect of inoculation with arbuscular mycorrhizal fungi on root traits and salt tolerance of Tagetes erecta

Abstract

Soil salinization is a global environmental problem. Arbuscular mycorrhizal (AM) fungi are capable of enhancing plant resistance to stress, for instance, improving plant tolerance to salinity stress. A pot experiment was carried out to determine the effects of AM fungi (Funneliformis mosseae, Rhizophagus intraradices, or F. mosseae and R. intraradices combined) and five different NaCl levels on the growth and physiology of Tagetes erecta under greenhouse conditions. The results showed that dual inoculation with F. mosseae and R. intraradices significantly increased total root length, root surface area, root volume, and root tip number of T. erecta plants under salt stress. Inoculation with AM fungi inhibited Na+ accumulation in leaves and promoted the absorption of N, P, K, and Ca in leaves, and thus increased ratios of K+/Na+, Ca2+/Na+, N/Na+, and P/Na+ in leaves under salt stress. Correlation analysis showed that the coefficient (0.964) between root volume and K+ in leaves was the highest, while the correlation between root surface area and Na+ content in leaves was remarkably negative (–0.95). AM fungi improved the osmotic regulation ability of plant cells, increased the activity of antioxidant enzymes, and reduced the damage of cell membranes. It is concluded that AM fungi improved salt tolerance of Tagetes erecta by changing root morphological traits, regulating uptakes of Na+ and other nutrient elements, and enhancing antioxidant enzyme activities and osmotic adjustment.

Keywords

• arbuscular mycorrhizal fungi
• mineral element equilibrium
• root traits
• salt tolerance
• tagetes erecta.