弥勒苣苔种子的休眠萌发特性（英文）

Dormancy and Germination of Paraisometrum mileense and Their Ecological Implications

弥勒苣苔为中国特有的濒危植物,一度被认为灭绝后又被重新发现,引起了学界及公众的广泛关注。种子库是保护珍稀濒危物种的一种有效手段,对物种开展种子保存需要较为深入的了解其种子休眠及萌发特性;但对于弥勒苣苔,现有资料十分有限,本研究系统地探讨了弥勒苣苔种子的休眠状态及萌发习性。在对其种子进行X光透视后,发现其种子的胚发育完全,且基本充满整个种子,因此认为该种子不具有形态休眠。在多个变温及恒温条件下对新鲜种子进行萌发测试,发现在较高温度(高于20℃)下萌发率很高且萌发迅速,赤霉素及低温层积处理能够显著提高种子在较低温度下(低于20℃)的萌发率,因此可以判定其种子存在浅的生理休眠。种子在恒温下的萌发率比相应的变温下萌发率要高,可能是其对所处荫蔽环境的一种适应。硝酸钾对种子萌发有显著的促进作用,在野外环境下,硝酸钾有对生境空窗及较少竞争的指示作用。

Paraisometrum mileense is endemic to China and was considered to be extinc, after its rediscovery it received much attention from the botanists as well as the public. Preserving its seeds in a seed bank gives a reliable way for long term conservation; however its seed dormancy status and germination requirements are scarcely studied. In this study we checked its embryo size by X-ray imaging, the presence of fully developed embryo ruled out the possibility of morphological dormancy. Freshly matured seeds germinated readily at relatively high temperatures （ over 20 ℃） and gibberellie acid as well as moist chilling promoted germination at lower temperatures （ below 20 ℃ ） significantly, this indicates the seeds are non-deep physiologically dormant. Seeds germinated better at constant temperatures, this is probably an adaption to shaded environment. The germination also responded significantly to KNO3, and KON3 is considered to be an indication of gap and less competition in the field.