The effect of mycorrhizal fungi on antioxidant activity of various cultivars of onion (Allium cepa L)

Abstract

Onion (Allium cepa L.) is one of the most important vegetables in the diet of Iranian people. Considering the importance of the organic crops production with high nutritional value, an experiment was conducted to study of the effect of mycorrhizal fungi on the antioxidant capacity of Onion (Allium cepa L.). Antioxidant activity of five cultivars of onion (Allium cepa L.) affected by mycorrhizal fungi were determined using ABTS, DPPH and FRAP assays (P≤ 0.01). Onion growth, mycorrhizal colonization rate, mineral nutrient concentrations and total flavonoid content were also quantified. Results indicate that inoculated plant was contained higher antioxidant activity than non-inoculated ones. The highest antioxidant activity was found in inoculated plants with Glomus versiforme. Results revealed that red cultivars namely Azarshahr and Rosita had higher antioxidant activity as compared to pink, yellow and white cultivars. Azarshahr cultivar contained highest antioxidant activity at 57.516±0.076, 57.266±0.016 and 7.617±0.012 (µM Ascorbic acid/g FW) for DPPH, ABTS and FRAP assays, respectively. The antioxidant activity of different cultivars of onion affected by mycorrhizal fungi showed the following order: red Azarshahr> red Rosita> yellow Gholi Ghesse> pink Horand> white Kashan. A significant positive correlation was obtained between ABTS, DPPH and FRAP assays ( P≤ 0.01).