Saussurea ochiaiana Kadota (Asteraceae) is a perennial herb endemic to serpentine areas in western Japan. To date, only two locations are known habitats for this species of unknown ecological requirements. Therefore, this study aimed to clarify the environmental factors that limit the germination and seedling growth of this species, which is an essential requirement for designing a suitable conservation strategy. Our germination experiments, in which the achenes were subjected to a gradually increasing temperature and a gradually decreasing temperature after short (1 month) or long (4 months) storage, indicated that the achenes required a long cold stratification for germination. In an experiment where plants collected at the study site were potted individually, they did not grow under strongly shaded conditions consisting of only 10% relative photosynthetic photon flux density (RPPFD), but grew well under moderately shaded conditions (50% RPPFD). No significant differences in seedling growth were observed among the three pH conditions tested (pH 4, 6, and 8). Although average seedling shoot weight was significantly larger at low Ca:Mg molar ratios (0.6 and 0.3) than at high substrate Ca:Mg molar ratios (15 and 1.5) in pot culture experiments, the difference between treatments was not very large (<20%). Habitat conditions suitable for the regeneration of this species are decreasing because of climate change and the depopulation of rural communities (reduction in management); therefore, urgent conservation strategies, including ex situ conservation, are needed.

中文翻译：

---

日本蛇纹岩地区特有的濒危雪莲属植物（菊科）发芽和幼苗生长的控制因素

雪莲角田（菊科）是日本西部蛇纹石地区特有的多年生草本植物。迄今为止，只有两个地点是这种生态要求未知的物种的已知栖息地。因此，本研究旨在阐明限制该物种发芽和幼苗生长的环境因素，这是设计合适的保护策略的基本要求。我们的发芽实验中，在短期（1个月）或长期（4个月）储存后对瘦果进行逐渐升高的温度和逐渐降低的温度，表明瘦果需要长时间的冷层积才能发芽。在一项将研究地点收集的植物单独盆栽的实验中，它们在仅由 10% 相对光合光子通量密度 (RPPFD) 组成的强遮荫条件下不生长，但在中度遮荫条件 (50% RPPFD) 下生长良好。在测试的三种 pH 条件（pH 4、6 和 8）中，未观察到幼苗生长的显着差异。尽管在盆栽实验中，低 Ca:Mg 摩尔比（0.6 和 0.3）下的平均幼苗重量明显大于高基质 Ca:Mg 摩尔比（15 和 1.5）下的平均幼苗重量，但处理之间的差异并不是很大（<20 %）。由于气候变化和农村社区人口减少（管理减少），适合该物种再生的栖息地条件正在下降；因此，需要采取紧急保护战略，包括异地保护。