Germination specifics and introduction into in vitro culture of Saposhnikovia divaricata (Turcz. ex Ledeb.) Schischk.

Abstract

The article examines the effect of storage conditions, mericarp processing, and germination conditions of the endemic Saposhnikovia divaricata (Turcz. ex Ledeb.) Schischk. on germination. The technological process of obtaining aseptic in vitro culture was perfected. Mericarps collected from introduced species in 2022 were examined. Explants were sterilized once or twice with 0.1% AgNO3 or 0.1% AgNO3, followed by the use of 10% Н2О2. The pericarp was removed from the sterilized mericarps, and seeds were germinated on a solid 1/2 Murashige and Skoog medium. Callus genesis was induced by culturing the true leaves of seedlings on a Murashige and Skoog medium supplemented with 2,4-dichlorophenoxyacetic acid (10 μM) and 6-benzylaminopurine (0–5 μM) in the dark. The seeds of S. divaricata exhibit shallow dormancy, and the most favorable conditions for their germination are stratification for 30 days at 4 °С or the scarification of mericarps and germination in an environmental chamber (photoperiod of 16.5 h and a daytime temperature of 27 °С with its slight decrease at night). Laboratory germination capacity reaches 94%. The absence of whole seeds at the end of the experiment suggests a small soil seed bank, which accounts for the vulnerability of natural populations along with monocarpy. The in vitro culture of S. divaricata was obtained. Pericarp removal from mericarps was shown to accelerate germination and improve germination capacity while significantly reducing contamination. A callus was formed on leaf petioles in 66% of explants on an auxin medium, while on a medium with auxin and cytokinin, it was formed across the entire surface of the leaf blade in 72% of explants. Further callus development occurred only on the auxin medium.