sophia soroori - Department of Horticultural Sciences, Aliabad katoul Branch, Islamic Azad University, Aliabad katoul,Iran
elham danaee - Department of Horticultural Sciences, Garmsar Branch, Islamic Azad University, Garmsar, Iran

The experiment was performed to study the effect of foliar application of citric acid on reducing the effects of drought stress on Calendula officinalis L., the effect of citric acid (۰, ۵۰ and ۱۰۰ mg l-۱) and different levels of drought (no stress: control, ۲۵, ۵۰ and ۷۵% field capacity) was studied as a factorial experiment based on a completely randomized design with three replicates in ۲۰۱۸ in greenhouses in northern Iran. The foliar application was applied in three stages with an interval of about ۲۰ days, including the six-leaf stage, full tillering and the appearance of the first bud. The results showed that drought stress and foliar application of CA significantly affected the parameters evaluated. The highest fresh and dry weight of shoots and roots, carotenoids, phenol and flavonoid were obtained in ۷۵% FC + CA ۵۰ mg l-۱. The maximum plant height, root length and number of flowers were for control irrigation + CA ۵۰ mg l-۱ and the highest longevity of the flower on the plant, total carbohydrate, rutin and total antioxidant activity was observed in ۷۵% FC + CA ۱۰۰ mg l-۱. In addition, treatment of control irrigation + CA ۱۰۰ mg l-۱ had the highest total chlorophyll and vitamin C and the ۲۵% FC treatment had the highest proline content. In general, irrigation of pot marigolds with ۷۵% FC and spraying with citric acid ۱۰۰ mg l-۱ had positive effects on plant growth and biochemical parameters

Antioxidant activity, Calendula officinalis, proline, Rutin, vitamin c