The effects of drought stress and sodium nitroprusside on growth indices and enzymatic activity of Satureja hortensis .

Drought is one of the major abiotic stresses limiting plant growth and crop production. Sodium nitroprusside also plays an important role as nitric oxide releasing compound in responding to biological and abiotic stresses and controlling plant growth. The aim of study was to investigate the effect of sodium nitroprusside on reducing effects of drought stress on Satureja hortensis, which is an abundant plant used in the food and pharmaceutical industries. For this purpose, the effect of sodium nitroprusside (0, 25 and 50 μM) and different drought levels (25, 50, 75 and 100% of FC) at 2019 in greenhouse condition on growth parameters and enzymatic activity were investigated as a factorial experiment based on a completely randomized statistical design. Plants were sprayed with sodium nitroprusside in 6 to 8 leaf stage, after 24 hours, drought treatment was applied. The second stage of treatments was done one week after first stage and after two weeks, growth indices and enzymatic activity were measured. The results showed that increasing drought stress significantly decreased the fresh and dry weight of shoots and roots and chlorophyll and increased the activity of antioxidant enzymes, phenol, proline and essential oil. Simultaneous treatment of drought and sodium nitroprusside significantly increased growth parameters and activity of antioxidant enzymes by reducing drought-induced oxidative stress. The highest percentage of essential oil (1.71%) was obtained in foliar application with 50 μM sodium nitroprusside and 25% in field capacity. Finally, foliar application of sodium nitroprusside reduced the negative effects of drought stress on savory.