Effect of Plant Growth Regulators and Explant Type on Direct Regeneration and Root Induction of Zarrin-Giah (Dracocephalum kotschyi Boiss) as a Medicinal Plant

Dracocephalum kotschyi Boiss. (Lamiaceae), known in Persian as “Zarrin-giah” or “Denaei Lemon Balm”, is a medicinal plant native to Iran. It is used in traditional remedies and as a flavoring in tea and doogh (a yogurt-based drink). Extracts of this species contain bioactive compounds with reported therapeutic properties. Efficient micropropagation protocols can support its conservation and large-scale production. This study evaluated plant growth regulator combinations and explant types for direct regeneration and rooting of D. kotschyi. A completely randomized experiment with three replications was conducted in ۲۰۲۵ to investigate the effects of cytokinin (BAP), auxin (NAA), and explant type (leaf, hypocotyl, and cotyledon) on regeneration, as well as the effects of Indole-۳-butyric acid (IBA) and culture media (MS and ½ MS) on rooting. Measured traits included regeneration percentage, number of shoots per explant, shoot length, number of leaves per shoot, rooting percentage, number of roots, and root length. Results showed that the combination of ۱ mg/L BAP and ۱.۵ mg/L NAA applied to hypocotyl explants produced the highest regeneration percentage and improved shoot quality. In the rooting stage, the interaction between medium type and IBA concentration significantly influenced root formation. The best rooting response, including ۱۰۰% rooting, occurred in ½ MS medium supplemented with ۱–۲ mg/L IBA. These results provide a practical protocol for efficient in vitro regeneration and rooting of D. kotschyi and support its micropropagation for medicinal use and conservation.

کلیدواژه ها:

Dracocephalum kotschyi ، BAP (۶-benzylaminopurine) ، NAA (α-naphthaleneacetic acid) ، regeneration