Seed Germination Ecology of the Cold Desert Annual Isatis violascens (Brassicaceae): Two Levels of Physiological Dormancy and Role of the Pericarp.
Seed Germination Ecology of the Cold Desert Annual Isatis violascens (Brassicaceae): Two Levels of Physiological Dormancy and Role of the Pericarp.
复制标题
冷漠沙漠年度伊萨蒂斯·阿拉斯彭（Brassicaceae）的种子发芽生态学：两种水平的生理休眠和果皮的作用。
DOI：
10.1371/journal.pone.0140983
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Baskin JM
中科院分区：
文献类型：
--
作者：
Zhou YM;Lu JJ;Tan DY;Baskin CC;Baskin JM
在我国西北部寒冷的沙漠地区，存在着不裂果实的紫云英科植物，这表明紫云英科植物具有适应性优势。我们推测，果皮的单种子silicles的板蓝根限制胚扩展，从而防止发芽1年或更长时间。因此，我们的目的是研究果皮在种子休眠和萌发的作用。利用完整硅和离体种子研究了后熟、赤霉素（GA 3）处理和低温层积对打破种子休眠的影响，并在试验园内对种子萌发物候进行了监测。果皮具有机械抑制新鲜种子萌发和促进非休眠种子萌发的作用，但它不促进持久种子库的形成。种子在Silicles在浇水的土壤中开始发芽早在秋季和发芽率高于孤立的种子。在第一个春天结束时，62%的种子在埋藏的硅里发芽，只有3%的种子保持不发芽和存活。20%~ 25%的种子具有非深度生理休眠（PD），75%~ 80%的种子具有中度生理休眠（PD）。不深PD的种子在夏季后熟，如果土壤潮湿，秋季在硅里发芽。后熟在夏季显着减少了冷层结所需的打破中间PD。种子队列中存在非深度和中间PD可能是一种赌注对冲策略。
The occurrence of various species of Brassicaceae with indehiscent fruits in the cold deserts of NW China suggests that there are adaptive advantages of this trait. We hypothesized that the pericarp of the single-seeded silicles of Isatis violascens restricts embryo expansion and thus prevents germination for 1 or more years. Thus, our aim was to investigate the role of the pericarp in seed dormancy and germination of this species. The effects of afterripening, treatment with gibberellic acid (GA3) and cold stratification on seed dormancy-break were tested using intact silicles and isolated seeds, and germination phenology was monitored in an experimental garden. The pericarp has a role in mechanically inhibiting germination of fresh seeds and promotes germination of nondormant seeds, but it does not facilitate formation of a persistent seed bank. Seeds in silicles in watered soil began to germinate earlier in autumn and germinated to higher percentages than isolated seeds. Sixty-two percent of seeds in the buried silicles germinated by the end of the first spring, and only 3% remained nongerminated and viable. Twenty to twenty-five percent of the seeds have nondeep physiological dormancy (PD) and 75–80% intermediate PD. Seeds with nondeep PD afterripen in summer and germinate inside the silicles in autumn if the soil is moist. Afterripening during summer significantly decreased the amount of cold stratification required to break intermediate PD. The presence of both nondeep and intermediate PD in the seed cohort may be a bet-hedging strategy.