The effect of two mycorrhiza fungi species on biochemical characteristic and aerial parts dry biomass of coriander (Coriandrum sativum L.) under cadmium stress

Nowadays, soil pollution to various heavy metals is one of the most important environmental issues in human societies, which has adverse effects on soil and soil flora and groundwater contamination. Among the heavy metals, cadmium with a half-life of about 20 years, its high mobility in the soil and absorption by the plant, has a significant toxicity that its presence in the food chain seriously threatens human health. A wide range of studies have shown that inoculation with mycorrhizal fungi increases the resistance of many plants against heavy metals.

In order to investigate the effect of mycorrhizal fungi on biochemical properties of coriander under heavy metal stress, a pot experiment was conducted in the greenhouses at Ferdowsi University of Mashhad. A factorial experiment based on completely randomized design with 2 factors and 3 replications was conducted. The first factor was heavy metal in 4 levels of 0, 20, 40, 80 mg/kg nitrate cadmium soil and the second factor was mycorrhiza fungi in 3 levels without fungi and Glomus mosseae and Glomus intraradicese application. The soil mixture included soil, leafy soil and sand in a ratio of 1: 1: 1. All traits were measured at flowering stage. The studied traits include aerial parts dry biomass, chlorophyll, b, a, electrolyte leakage, soluble carbohydrate, antioxidant activity, total phenol, total flavonoids and proline. Data analysis using Minitab 17 software was done.

The results were showed that by increasing the concentration of cadmium, the amount of electrolyte leakage, soluble carbohydrate, antioxidant activity, total phenol, total flavonoids and proline increased. However, with increasing cadmium concentration, the amount of dry biomass of aerial parts, chlorophyll, a, b and carotenoids decreased. So, with increasing cadmium concentration, the amount of aerial parts dry biomass of coriander decreased by 40% compared with the control. Based on this study, using of mycorrhizal fungi under cadmium pollution reduced the stress influence, so that the highest amount of aerial parts dry biomass was found in plants treated with mycorrhizal and without cadmium application. The lowest amount dry biomass of aerial parts was found in without mycorrhizal with highest nitrate cadmium concentration (80 mg/kg soil). The highest amount of proline, soluble carbohydrate, phenol, antioxidant activity, and total flavonoids was observed in plants which treated with the highest nitrate cadmium concentration (80 mg/kg soil) and Glomus intraradicese application.

So that inoculated plants with mycorrhizal fungi had more dry biomass of aerial parts than plants without mycorrhiza. According to the results of this study, in the conditions of environmental stresses such as cadmium stress, the use of mycorrhizal fungi reduces its destructive effects, which can be used as a management solution in heavy metal contaminated areas. In general, the results of this study showed that application of Glomus mosseae fungus in cadmium stress has a better effect on the traits and its application is recommended in this condition.