Effects of endophytic fungus Serendipitaindica on growth and nutritional characteristics of quinoa undersalinity stress conditions

Quinoa (Chenopodium quinoaWilld.) is a high-yielding pseudo-cereal crop, belonging to the Chenopodiaceae plants, shows tolerance to salinity stress. As a chenopod plant, it could not establish a symbiosis relation with mycorrhizal fungi, but there are evidences that the Serendipitaindica (endophytic fungus) could enter the root and more likely improves the tolerance of quinoa against salt stress. This study was performed as a pot experiment in Completely Randomized Factorial Designs (CRFD) with three replications in a sterilized sandy loam soil. Experimental factors included two levels of S. indica (inoculated and non-inoculated) and salinity levels of 1.47 (initial electrical conductivity of soil), 5, 10, 20 and 30 dS/m. The interaction effect of salinity stress and fungal inoculation was significant for studied traits in both shoot and root (P <0.05), except for the concentrations of nitrogen and phosphorus in the root. The concentrations of phosphorus, potassium, calcium and magnesium, growth traits and percentage of root colonization in quinoa were significantly reduced by increasing salinity levels (P <0.05). S. indica increased root dry weight in control, 5 and 10 dS/m by 23.45, 25.66 and 25.57%, compared to no-fungal treatment, respectively. At initial electrical conductivity (1.47dS/m), shoot dry weight increased by 9% in inoculated plants compared to the non-inoculated treatment. Inoculation with S. indica reduced the concentration of root sodium at salinity levels of 10, 20 and 30 dS/m by 30.49, 66.78 and 43.55%, respectively, compared to the non-inoculated treatment. In the aerial part, the fungus could reduce the sodium concentration at 10, 20 and 30 dS/m by 20.96, 13.28 and 10.24%, respectively, compared to the treatment without the fungus. Based on the results, inoculation with the fungus significantly increased the concentrations of nitrogen, phosphorus and potassium in shoots at 20 and 30 dS/m.