Studying the effect of different concentrations of ۲,۴-D on the growth and secondary metabolites production in hyssop (Hyssopus officinalis) in in vitro culture

The hyssop belongs to the Lamiaceae family and is used in traditional medicine and in the pharmaceutical and food industries. It has antibacterial, antifungal, antioxidant and antispasmodic activities and is used effectively in the treatment of cough, bronchitis, severe asthma and other respiratory diseases. In this study, the effect of different concentrations of ۲,۴-D (۰, ۱, ۲, ۳, ۴ and ۵ mg/liter) on callusing, growth and production of secondary metabolites of the studied hyssop plant. The results showed that the use of different concentrations of ۲,۴-D had a significant effect on the percentage of callusing, seedling and root length, seedling fresh weight, number and ​​leaf surface area, content of rosmarinic acid, folic acid, quercetin, luteolin, flavonoid and antioxidant activity. In general, the highest percentage of callusing (۹۷.۴۰%) was achieved with the application of ۳ mg/L ۲,۴-D. The maximum seedling length (۸.۹۲ cm), root length (۱.۶۶ cm), seedling fresh weight (۰.۱۵ g), leaf surface area (۱.۴۴ cm۲), and number of leaves (۲۱.۸۰) ۲,۴-D were obtained under the control condition. The maximum amount of rosmarinic acid (۰.۶۴ μg/g dry weight) and luteolin (۲.۴۲ μg/g dry weight) was observed in the presence of ۲ mg/L ۲,۴-D. The maximum contents of folic acid (۳۶.۶۵ μg/g dry weight), quercetin (۱.۷۲ μg/g dry weight), and flavonoid (۲.۴۸ mg quercetin/g dry extract) were obtained with application of ۱ mg/L ۲,۴-D.Also, the maximum antioxidant activity (۳.۹۸ μg/mL) was obtained by adding ۴ mg/L ۲,۴-D.