Evaluation the Effects of Salicylic Acid and Methyl Jasmonate on the Scent of Purple Coneflower (<i>Echinacea purpurea</i> L. Moench) Flowers

Abstract

Flowers of many plants emit scents, which are almost always a complex of small volatile organic compounds such as essential oils that they are the ones who give the fragrance of flowers and also have medicinal curative properties. So, the most common topic in the field of plant sciences, has been focused on improving flower’s quality and quantity by application of plant growth regulators (PGRs) to modify growth and flowering patterns. For this purpose, a research was conducted at the research field of agricultural faculty of Zanjan university on purple coneflower during farming years of 2017-2018 and 2018-2019 by application of salicylic-acid (0 (control), 50, 100 and 150 mM) and methyl-jasmonate (0 (control), 50, 100 and 200 μM). In the first year of experiment, treatments were sprayed on plants (four plants per plot) in two stages (20 days apart). In the second year, they were also sprayed on remaining plants as the first year. The results indicated that the highest percentage of essential oils in the flower heads of purple coneflower was related to treatment of 100 mM salicylic acid and 50 μmol methyl jasmonate in the first year and treatments of 100 mM salicylic acid and 50 and 100 μmol methyl jasmonate in the second year. The highest percentage of total compounds of essential oils in the first year was related to treatment of 50 mM salicylic acid and 50 μmol methyl jasmonate and in the second year was related to treatment of 100 mM salicylic acid and 100 μmol methyl jasmonate. The identified compounds in the essential oils of purple coneflower samples included hydrocarbon monoterpenes, oxygenated monoterpenes, hydrocarbon sesquiterpene, oxygenated sesquiterpenes and other compounds. The highest percentage of total compounds of essential oils in the first year was related to treatment of 50 mM salicylic acid and 50 μmol methyl jasmonate and in the second year was related to treatment of 100 mM salicylic acid and 100 μmol methyl jasmonate. Also, most of compounds increased in the second year compared to the first year.