Application of Thidiazuron (TDZ) for in vitro multiplication of yarrow (Achillea millefolium L.) and profile of volatile compounds

This study evaluated in vitro multiplication and volatile production of yarrow ('A. millefolium' L.) a medicinal plant, with different Thidiazuron (TDZ) concentrations. Explants with 10 mm length were inoculated into flasks containing 40 mL of Murashige and Skoog (MS) medium supplemented with 0.25, 0.50, 0.75 and 1.00 mg L-1 TDZ, and the control without the regulator. The experimental design was completely randomized with five replicates per treatment. At 45 days of culture, the number of shoots, shoot length and dry mass of shoots were evaluated. It was also checked the changes of the volatile constituents of leaves, in all treatments and plants within 30 and 75 days in MS free-hormone medium. The volatiles of leaves were analyzed by headspace-GC/MS. The application of 0.75 mg L-1 of TDZ showed the best combination of variables number, length and dry mass of shoots. Regarding volatile compounds, 32 constituents were identified, and the major constituents in all treatments were sabinene, 1.8-cineole, borneol, beta-caryophyllene and beta-cubebene. It was observed significant changes in the profile, number and contents of the constituents with presence of TDZ.