Beneficial effects of arbuscular mycorrhizal fungi on wheat (Triticum aestivum L.) nutritional status and tolerance indices under soil salinity stress

Abstract

This pot experiment was conducted to evaluate the effects of the inoculation by the mycorrhizal species (Funneliformis mosseae and Rhizophagus intraradices) in salt-tolerant and -sensitive wheat cultivars (Roshan and Bahar) under three salinity levels (0, 75, and 150 mM NaCl). Salinity significantly decreased shoot and root biomass of both cultivars but to a smaller extent in Roshan. The reductions in biomass were accompanied by decreases in N, P, and K and increases in proline and Malondialdehyde (MDA) and antioxidant enzyme activity. The salt-tolerant cultivar showed less decreases in nutrient content and higher increases in proline and antioxidant enzyme activities. Peroxidase as compared to catalase and ascorbate peroxidase showed a higher contribution in salt tolerance induction. Mycorrhizal inoculation improved plant growth by increasing nutrient content, antioxidant enzyme activity, and decreasing lipid peroxidation. The positive effects of inoculation were in most cases greater on the plants inoculated by F. mosseae. The superiority of this species was associated with lower increases in MDA and H2O2 accompanied by greater increases in the root area and volume, shoot N, P, and K/Na and antioxidant enzyme activities. Higher benefits from mycorrhizal inoculation were taken as the level of salinity was increased. The salt-tolerant cultivar was more positively responsive to mycorrhizal inoculation under non-saline treatment, but the sensitive cultivar was more affected by inoculation under saline conditions. The results from this experiment showed that mycorrhizal inoculation could promote the growth and salt tolerance of wheat cultivars by improving osmoregulation, antioxidant enzyme activity, and reducing lipid peroxidation.