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

<i>Tulipa auliekolica</i> and <i>Tulipa turgaica</i> 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 <i>Tulipa</i> 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, <i>T. auliekolica</i> and <i>T. turgaica</i>. Species-specific temperature regimes for seed stratification were established. Maximum germination of <i>T. auliekolica</i> was achieved at alternating temperatures of 4/10 °C, and of <i>T. turgaica</i> 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 <i>Tulipa</i> 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 <i>Tulipa</i> species.