Mycorrhiza Fungi Mitigate Chilling Stress in Purple Coneflower (Echinacea purpurea L.) through Regulating Antioxidant Activity and Nutrient Uptake

Medicinal plants play important role in industrial production of medicines. To assess the response of purple coneflower (Echinacea purpurea L.) to mycorrhiza fungi (Glomus versiforme, and G. intraradices,) under chilling stress (25, 8 and 4°C) an experiment was conducted using a factorial design based on a completely randomized block design with three replications at the greenhouse conditions. Chilling stress increased proline, glysine-betain, soluble sugar, soluble protein, carotenoid, antioxidant activity such as (GPX, CAT, SOD and APX) and decreased chlorophyl a, b and total chlorophyl, N, P, Mg, Fe and K content of leaf, which resulted in the reduction of grain yield. Applying mycorrhiza, enhanced grain yield by reducing some detrimental impacts of chilling stress on chlorophyll a, b and total chlorophyl, carotenoid, osmolyte contents, antioxidant activity and leaf element contents. G. versiforme at optimal temperatures and G. intraradices at 4 and 8°C showed significant contributions to enhancing grain yield. Consequently, when purple coneflower is subjected to a temperature of 4°C during growth, the use of G. intraradices could prevent the grain yield reduction.