alleviating adverse effects of salt stress in pot marigold (calendula officinalis l.) by foliar spray of silicon and nano-silicon under greenhouse and field conditions

Purpose: in order to assay the impact of silicon (si) and nano-si on morphological and physiological traits of pot marigold (calendula officinalis l.) under salt stress conditions, an experiment was conducted under greenhouse and field conditions. research method: the experiment was based on a completely randomized design including two levels of saline water (1.1 (control) and 6.1 ds m-1) and three levels of foliar spray (0, 2.5 mm si and nano-si) with 4 replications. findings: salinity stress decreased the vegetative and flowering parameters of pot marigold in the both conditions. supplemental si and nano-si increased the dry weight of flowers under salt stress in the greenhouse (47 and 71%) and field (86 and 94%) conditions, respectively. foliar application of nano-si enhanced the flower total phenols of salt-stressed plants by 76% (greenhouse) and 50% (field), respectively. under saline conditions, the use of nano-si increased the flower antioxidant activity in the field by 17% in comparison to the control. supplemental si and nano-si could reduce the negative impacts of salinity through increasing enzymatic and non-enzymatic antioxidants, accumulating soluble sugars, improving water relations, and enhancing chlorophyll content. research limitations: no limitations were found. originality/value: based on the results of present study, the use of si and nano-si improved the growth and physiological characteristics of pot marigold under saline conditions.