Influence of plant growth regulators on in vitro regeneration of Saposhnikovia divaricata (Turcz. ex Ledeb.) Schischk

Saposhnikovia divaricata (Turcz. ex Ledeb.) Schischk is a medicinal plant with a broad spectrum of pharmacological activities, which are attributed to the presence of various bioactive compounds, including chromones. The uncontrolled harvesting of this plant has resulted in the depletion of its natural resources. The ability of S. divaricata to regenerate in vitro was studied. Aseptic culture was established by sterilizing seeds and germinating them, both with and without the pericarp. Adventitious shoot formation through direct morphogenesis was achieved on Murashige and Skoog medium in the presence of different cytokinins: benzylaminopurine, meta-topolin, and thidiazuron, at concentrations of 0.1 µM, 0.5 µM, and 1.0 µM. It has been determined that the most preferable explants were the cotyledonary nodes of aseptic seedlings, as they enable the rapid production of 1.4 ± 0.5 to 10.2 ± 2.0 microshoots per explant, depending on the type and concentration of the cytokinin used. Successful regeneration also occurred from the first true leaves of seedlings in vitro. Microshoots were formed directly from the explant tissues, with their quantity ranging from 1.7 ± 0.7 to 4.4 ± 0.9. The highest number of microshoots was induced by thidiazuron, but after cultivation with meta-topolin, the regenerated plants showed the highest frequency of rooting, ranging from 66 to 97%. Somatic embryoids were obtained when the first true leaves were cultivated with 2,4-dichlorophenoxyacetic acid (10.0 µM). Morphogenesis occurred via the indirect pathway (through the callus formation stage), accompanied by the formation of up to 24.2 ± 6.1 somatic embryoids, with a rooting frequency reaching 96%. These studies provide a preliminary basis for developing a protocol for the clonal micropropagation of S. divaricata.