The effect of sodium nitroprusside and potassium silicate on growth indices and antioxidant activity of Rosemary (Rosmarinus officinalis L.) under deficit irrigation conditions

Water deficit is one of the most critical factors limiting plant growth and production, and identifying strategies to increase plant tolerance to this stress is of high practical importance. Sodium nitroprusside, as a nitric oxide donor, and potassium silicate, as a source of silicon and potassium, play important roles in plant tolerance to stress. In this study, the effect of foliar application of sodium nitroprusside and potassium silicate on growth indices and antioxidant activity of the medicinal plant rosemary (Rosmarinus officinalis L.) under different levels of drought stress was investigated. The experiment was conducted as a factorial completely randomized design with three replications in a commercial greenhouse located in Karaj, Iran. The treatments included water deficit levels (control, ۳۰%, and ۷۰% of field capacity) and foliar application of sodium nitroprusside (۰, ۲۵, ۵۰, and ۱۰۰ µM) and potassium silicate (۰, ۲۵, ۵۰, and ۱۰۰ mg/L), along with their interactions. Deficit irrigation was applied using the gravimetric method, and foliar spraying with sodium nitroprusside and potassium silicate was conducted three times every other day. The results showed that drought stress significantly reduced growth traits and antioxidant activity while increasing ion leakage and proline accumulation. In contrast, the application of sodium nitroprusside and potassium silicate significantly reduced the harmful effects of stress by enhancing the antioxidant defense system. The highest fresh and dry weight of shoots, fresh and dry weight of roots, phenol content, and activities of catalase, superoxide dismutase, and peroxidase enzymes were observed in the treatment with ۱۰۰% field capacity + ۵۰ µM sodium nitroprusside. The most significant root length, root volume, plant height, total chlorophyll content, flavonoid content, and protein content were obtained in the treatment with ۱۰۰% field capacity + ۱۰۰ mg/L potassium silicate. The highest percentage of cell membrane ion leakage and proline content were recorded in the ۳۰% field capacity treatment. Overall, the results of this study indicate that the application of sodium nitroprusside and potassium silicate can be used as a strategy to increase the tolerance of rosemary (Rosmarinus officinalis L.) to drought and maintain its yield and quality under water-limited conditions.

کلیدواژه ها:

Antioxidant ، Enzyme ، Nitric Oxide ، Silicon ، آنزیم ، آنتی اکسیدان ، سیلیکون ، نیتریک اکسید