In Vitro Propagation of Endemic Kazakh Tulips: Effects of Temperature and Growth Regulators

Tulipa auliekolica and Tulipa turgaica have been recently described as endangered species endemic to Kazakhstan, which require urgent conservation amid rising human impact and climate change. Biotechnology offers effective tools for conserving such rare species; however, species-specific in vitro protocols tailored to their biological traits remain largely unreported. This study aimed to develop an in vitro propagation protocol for these rare Tulipa species by investigating the effects of different temperature regimes and phytohormone treatments. We conducted a study on the in vitro propagation of two recently described species, T. auliekolica and T. turgaica. Species-specific temperature regimes for seed stratification were established. Maximum germination of T. auliekolica was achieved at alternating temperatures of 4/10 °C, and of T. turgaica at 10/20 °C. No seed germination from either species occurred at a constant temperature of 20 °C. Bulbs cultured on Murashige & Skoog (MS) medium supplemented with 90 g/L sucrose and the growth regulators mT (meta-topolin) and BAP (6-benzylaminopurine) were effective in stimulating the formation of up to 4–7 microbulbs. Cultivation on a medium supplemented with 0.5 mg L⁻¹ IBA (indole-3-butyric acid) resulted in the formation of mature bulbs covered with scales. These results can be successfully used in biodiversity conservation programs for the endemic Tulipa species. In addition, they provide a valuable basis for future biotechnological research, including microclonal propagation, the establishment of gene banks, and the development of reintroduction methods for Kazakh endemic Tulipa species.