Evaluation of Saffron extract and essential oil and salicylic acid treatment on germination and early growth stages of long fescue (Festuca arundinacea Scherb.) under sodium chloride stress

Introduction: Every year, a large part of the petals of saffron flowers in Iran are unused. The dehydration of these petals can be used as a stimulant for germination and complement plant growth. In fact, the extract and essential oil of saffron flower petals contain certain amounts of Safranal, which has a chemical structure similar to beta-cycloidal (Corradi and Michelli, 1979). B-cycloidal is a valuable compound for improving product strength, especially in harsh environmental conditions (Dickinson et al., 2019). In this study, we evaluate the effects of the extract and essential oil of saffron flower petals on germination and early-stage growth of Festuca arundinacea Scherb under salt stress.
Material and methods: In the first experiment, pretreatment of salicylic acid on germination was evaluated in three levels (0, 0.1, and 0.5 mM). Saffron petal water, saffron flower essential oil, and saffron stigma aqueous extract (50 μL / mL) on Tall fescue seeds treated with three concentrations of sodium chloride (0, 3000, and 6000 mg /L) were conducted in a factorial test in a completely randomized design with three replications.
In the second experiment after Tall fescue seedlings establishment, irrigation was carried out regularly and fertilizer (20-20-20) with a concentration of 3% was used as a solution in the irrigation water. After 28 days and first mowing the salinity treatments (0, 3000, and 6000 mg/L) were started and continued for 4 weeks. Saffron petal juice treatments with three concentrations (control, 250, and 500 μL /100 mL) and saffron stigma essential oil (control, 40 and 125 μL /100 mL) interaction with Sodium chloride treatments (non-salt stress, 3000 and 6000 mg /L) were evaluated
Results and discussion: Salicylic acid (0.1 mM) improved germination percentage by 17.2% under salinity stress of 3000 mg /L. Stem length (67%) and root weight (60%) increased with a concentration of 50 μL /mL saffron petal juice under salinity stress compared to the control. The most suitable level of salicylic acid for improving the germination index under sodium chloride stress was pretreatment with a concentration of 0.1 mM. The interaction of 6000 mg/L salinity with saffron petal juice (SEES11) caused a significant (42%) increase in seedling length compared to the control (Figure 7). Beta-cyclocitral (safranal) in the roots of rice plants under salinity stress significantly stimulates root and stem growth and can be used in a valuable way to improve product yield, especially in harsh environmental conditions (Dickinson et al., 2019). Increasing the concentration of sodium chloride increased the amount of hydrogen peroxide and the activity of peroxidase and catalase enzymes. The use of saffron stigma essential oil treatment with a concentration of 40 μL/100 mL caused a significant decrease in the amount of hydrogen peroxide and a significant increase in the activity of catalase and peroxidase enzymes. Sodium chloride treatment increased the amount of hydrogen peroxide, catalase and peroxidase activities.
Conclusions: Petal water and the essential oil of saffron consumption significantly increased the amount of hydrogen peroxide and the activity of catalase and peroxidase enzymes. Using a longer time or higher concentrations of stigma essential oil and saffron petal juice may increase antioxidant enzyme activities, which helps establish the plant. Finally, it can improve the response of the plant to environmental stresses, especially sodium chloride stress.