Sodium nitroprusside application regulates antioxidant capacity, improves phytopharmaceutical production and essential oil yield of marjoram herb under drought

S Farouk,Arwa Abdulkreem Al-Huqail

doi:10.1016/j.indcrop.2020.113034

S Farouk, Arwa Abdulkreem Al-Huqail

Open Access

https://doi.org/10.1016/j.indcrop.2020.113034

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Abstract

Nitric oxide (NO) represents a crucial signal particle that plays a pivotal function in plant development, but its roles in improving drought tolerance in marjoram still unknown. The protective roles of foliage-spraying NO (as sodium nitroprusside, SNP; 0, 30, and 60 μM) on inducing drought tolerance in marjoram herb was evaluated by measuring the antioxidant defense system and phytopharmaceutical characteristics in an outdoor pot experiment. Under well-watered, SNP (30 and 60 μM) application significantly enhanced growth, essential oil (EO) yield, up-regulating antioxidant system, and improved water use efficiency (WUE) compared to untreated plants (0 μM SNP). Drought significantly inhibited marjoram growth, WUE, EO yield, catalase, and peroxidase activity as well as herbal extract reducing power and reflective index, whereas oxidative biomarkers (hydrogen peroxide, lipid peroxidation, protein carbonyl group accumulation, and electrolyte leakage) and EO specific gravity were drastically amplified relative to well-watered plants in the absence of SNP. Alternatively, under drought, SNP application mitigated drought induced-oxidative burst and improved WUE that associated with increasing plant biomass and EO assimilation relative to those in drought-affected herbs only. Phytopharmaceuticals of herbal extract (ascorbic acid, total soluble phenol, anthocyanin, and flavonoid) were significantly improved by drought and/or SNP foliar application. The promotive roles of SNP in moderating the depressing effect of drought on marjoram was attributable to up-regulating antioxidant capacity, improving secondary metabolite assimilation, and increasing WUE that accelerate drought tolerance and EO yield as well as improved EO fractions. The existing outcomes open innovative opportunities for obtaining precious natural antioxidants and phytopharmaceuticals by using arid regions.

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