چكيده لاتين :
ntroduction: Marigold (Calendula officinalis L.) is an ornamental and medicinal plant from the family Asteraceae that is originated from the Mediterranean region, Western Asia, and Central Europe. The application of steroids to plants is an interesting subject. Steroid hormones, such as estradiol, stimulate growth and development and root and stem elongation. Mammalian sex hormones (progesterone, β-estradiol, and androsterone) stimulate antioxidant systems and enhance the growth of plants. Jasmonic acid and methyl jasmonate (MeJA) widely occur in plants and are involved in a wide range of processes, including fruit ripening, the production of viable and active pollens, root growth, tendril coiling, and protection against pathogens and insects. The present research aimed to investigate the effects of methyl jasmonate (MeJA) and estradiol on some physiological traits, including vegetative parameters and antioxidant properties of marigold.
Experimental: The study carried out as a factorial experiment based on a Randomized Complete Block Design with two factors including MeJA at four rates (0, 10, 100 and 500 μM) and estradiol at four rates (0, 1, 5 and 10 mg/l) with 16 treatments, 3 replications, and 48 plots. The growth regulators were used as the foliar application at three phases in 2-week intervals. The recorded traits included leaf number, plant fresh and dry weight, anthocyanin, carotenoid, chlorophyll a, b and total, catalase activity, peroxidase enzyme, petal flavonoid, and antioxidant property.
Results: The analysis of variance revealed that the simple effect of MeJA was significant on leaf number, antioxidant capacity, total chlorophyll, and petal carotenoid. Also, the simple effect of estradiol was significant on leaf number, plant dry weight, anthocyanin, peroxidase enzyme, and flavonoid. It was found that MeJA × estradiol was significant for leaf number, total chlorophyll, petal carotenoid, anthocyanin, catalase enzyme activity, peroxidase enzyme activity, antioxidant capacity, plant dry weight, and chlorophyll a and b content. The results showed that MeJA at the rate of 10 μM was most effective in the number of leaves and total chlorophyll. At the rate of 500 μM, it was also effective in the antioxidant capacity. Estradiol at the rate of 10 mg/l was the best treatment for dry weight, peroxidase activity, and flavonoid content. It was observed that 10 μM MeJA × 10 mg/l estradiol resulted in the highest leaf number and chlorophyll content and 500 μM MeJA × 10 mg/l estradiol was related to the highest chlorophyll b content and peroxidase enzyme activity. According to the results, it is recommended to apply estradiol and MeJA to improve the pigments and antioxidant capacity of Calendula officinalis. Dry weight and leaf number were increased with estradiol application. The results confirmed that the application of naturally occurring compounds, like MeJA and steroids, can increase secondary metabolites such as flavonoids and antioxidant enzymes and activity.
Conclusion: To further learn about plant regulators in the future, it is recommended to examine the impact of MeJA and steroids on other plants under biotic and abiotic stresses.
Extension: Based on the results, growers can apply estradiol and MeJA to improve the pigments and antioxidant capacity of Calendula officinalis.
