earticle

영어

Species diversity and habitat transformation are affected by climate change, both directly and indirectly, with correlations observed in terms of species specificity. Alpine and subalpine climate-sensitive plants frequently exhibit morphological plasticity by adjusting their physiological and reproductive processes to adapt to significant environmental changes. Bupleurum euphorbioides is a cold-adapted herb found on the rocky slopes of South Korea. Owing to climate shifts and human activities, its population has decreased. We conducted studies on pollen morphology, pollen viability, and sexual systems to better understand environmental adaptations. In this study, we observed extensive synchrony in the sexual maturity phases of B. euphorbioides flowers both within and across individual inflorescences. The population exhibited highly synchronized mass flowering, which may represent an adaptation to challenging environments where a brief breeding season necessitates the simultaneous blossoming of a large number of flowers. We documented the sexual expression of B. euphorbioides and distinctly observed protandry, wherein pollen presentation preceded stigma receptivity. All examined individuals of B. euphorbioides exhibited significant variation in pollen viability ranging from 0.04% to 95.54%, even within a single population. Meiotic failure or apomictic reproduction is possible in individuals with low pollen fertility. While fertile pollen grains displayed a prolate shape with a well-stained cytoplasm, sterile pollen grains were characterized by their smaller size and lack of stained cytoplasm. Therefore, more thorough observations of the meiotic behavior using an expanded range of plant materials are necessary to investigate the function of the distinct reproductive system of B. euphorbioides.