Cadellia pentastylis (Surianaceae) is an Australian endemic threatened rainforest tree. Irregular flowering and fruiting events coupled with high rates of infertility and insect predation has meant that seed testing has not been possible for this species. Seeds were opportunistically collected from a wild population in early 2021, which allowed for the first germination tests to be conducted. In this study, the presence of physical dormancy was examined by performing an imbibition test using scarified and non-scarified seeds. We also investigated whether a 5-min heat shock treatment at temperatures ranging from 60 to 120°C improved germination success. The presence of physiological dormancy was also examined by recording germination success following a gibberellic acid or smoke-water pre-treatment. Both scarified and non-scarified seeds readily imbibed water over a 72-h period, and several seeds had germinated in both treatments after 48 h. Final germination proportion and t50 following a heat shock, gibberellic acid or smoke-water pre-treatment did not significantly differ from the controls. We conclude that C. pentastylis seeds are non-dormant. Although a palisade cell layer has been reported in the endocarp, our results suggest that this layer may not be sufficiently formed to restrict germination. We recommend that seeds are collected from populations following dispersal and propagated shortly after or stored as conservation collections in ex situ Seedbanks.

五叶草(Surianaceae) 是澳大利亚特有的受威胁雨林树。不规则的开花和结果事件加上高不育率和昆虫捕食意味着该物种无法进行种子测试。种子是在 2021 年初从野生种群中机会性地收集的，这使得可以进行第一次发芽测试。在这项研究中，通过使用划痕和非划痕种子进行吸胀测试来检查物理休眠的存在。我们还研究了在 60 至 120°C 的温度范围内进行 5 分钟的热休克处理是否能提高发芽成功率。还通过在赤霉酸或烟水预处理后记录发芽成功来检查生理休眠的存在。划痕和未划痕的种子在 72 小时内都很容易吸水，并且在 48 小时后在两种处理中都有几颗种子发芽了。最终发芽比例和t 50在热休克、赤霉酸或烟水预处理后与对照组没有显着差异。我们得出结论，C. pentastylis种子是非休眠的。尽管已报道在内果皮中有栅栏细胞层，但我们的结果表明，该层可能没有充分形成以限制发芽。我们建议在散布后从种群中收集种子，并在不久后繁殖或作为保护收藏品储存在异地种子库中。