Research Institute of Resources Insects, Chinese Academy of Forestry, Kunming, 650224, China.
China National Bamboo Research Center, Hangzhou, 310012, China.
Sci Rep. 2018 Feb 16;8(1):3205. doi: 10.1038/s41598-018-21469-9.
Dormancy is an innate constraint on germination that occurs across all life forms. In this study, we investigated the seed dormancy release and germination characters of Taxus yunnanensis by exploring the seed morphology, permeability, germination inhibitors, endogenous hormones, and embryo germination in vitro during wet sand storage. Our results showed that seeds and embryos grew to a critical size to germination and permeability increased with the extension of storage. Seed coat and kernel methanol extracts reduced Brassica campestris seed vigor index. The in vitro embryo germination rate increased by 12.20% after storage for 30-360 d, whereas seed germination occurred after 450 d. Gibberellic acid and zeatin riboside contents were relatively stable, whereas abscisic acid (ABA) content decreased; indole acetic acid (IAA) content and the IAA/ABA ratio showed increasing trends. These results indicate that ABA is the key inhibitor of germination in Taxus. The chemical(s) in seed coat and kernel cause the inhibition of seed germination. Taken together, Taxus seeds have morphophysiological dormancy, in which the embryos can continue to grow and hormone imbalance inhibits further development and germination. Further, seed dormancy is active even during the middle of storage and shows "double peaks" during the entire dormancy process.
休眠是一种普遍存在于所有生命形式中的固有约束，它限制了种子的萌发。在本研究中，我们通过探索种子形态、透性、萌发抑制剂、内源激素以及湿沙贮藏过程中的离体胚萌发，研究了云南红豆杉种子的休眠解除和萌发特性。结果表明，随着贮藏时间的延长，种子和胚生长到临界大小以促进萌发，透性增加。种皮和核甲醇提取物降低了白菜种子活力指数。贮藏 30-360d 后，离体胚萌发率提高了 12.20%，而 450d 后种子开始萌发。赤霉素和玉米素核苷含量相对稳定，而脱落酸（ABA）含量下降；吲哚乙酸（IAA）含量和 IAA/ABA 比值呈上升趋势。这些结果表明，ABA 是云南红豆杉种子萌发的关键抑制剂。种皮和核中的化学物质导致种子萌发受到抑制。综上所述，云南红豆杉种子具有形态生理休眠，其中胚可以继续生长，激素失衡抑制了进一步的发育和萌发。此外，即使在贮藏中期，种子休眠也是活跃的，并且在整个休眠过程中呈现“双峰”现象。
