Towards an Understanding of Factors Controlling Seed Bank Composition and Longevity in the Alpine Environment
Towards an Understanding of Factors Controlling Seed Bank Composition and Longevity in the Alpine Environment
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DOI：
10.1007/s12229-014-9150-2
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发表时间：
2015-03-01
期刊：
影响因子：
4
通讯作者：
Liu, Baolin
中科院分区：
文献类型：
--
作者：
Jaganathan, Ganesh K.;Dalrymple, Sarah E.;Liu, Baolin
长期以来，种子从土壤种子库中再生的能力一直被认为是植物在高度变化的高山环境中建立新生态位的关键生存策略。然而，高寒生态系统种子库发展的进化/选择力量的基本方面在很大程度上是未知的。在这里，我们开发了一个模型，该模型描述了种子脱落时的休眠，高温要求和特定的光照/黑暗制度可以阻止秋季发芽，从而有助于种子持续到下一个生长季节。综述了这些因素同步发芽与生长季节的好处。此外，还讨论了产妇环境的气候变化对这些因素的影响。结果表明，生长季节的环境条件在一定程度上控制了种子的持久性，未能发芽的种子可以延续到下一季节。小种子（< 3毫克）和圆形种子的物种比大种子或扁平种子更容易在土壤中持续5年以上。然而，一些大种子物种也具有建立短期持久性库的潜力。一项文献调查显示，88%的高山种子质量< 3毫克。种子大小与平均发芽时间（MGT）的关系较弱，这表明大种子物种的持久性降低不能通过更快的发芽来抵消，但其他因素对萌发的综合影响仍然是一个开放的研究领域。作者认为，由于缺乏专门的传播结构，大多数物种的长距离传播（LDD）受到限制。然而，在众多的传播方式中，大多数物种倾向于通过风传播。因此，高山环境的种子植物更倾向于建立种子库，并将发芽的风险分散到许多年，而不是分散到其他小气候。
The ability of seeds to regenerate from soil seed banks has long been recognized as a key survival strategy for plants establishing new niches in highly variable climates of alpine environments. However, the fundamental aspects of evolutionary/selective forces for seed bank development in alpine ecosystems are largely unknown. Here, we developed a model that describes dormancy, a high temperature requirement and a specific light/darkness regime at the time of seed shedding can preclude autumn germination, thus contributing to seed persistence until the next growing season. The benefits of these factors synchronising germination with the growing season are reviewed. Additionally, the importance of climatic variations of maternal environment affecting some of these factors is also discussed. It is suggested that the environmental conditions during the growing season partly control the seed persistence and seeds that fail to germinate are carried over to the next season. Species that have small (< 3 mg) and round-shaped seeds tend to persist more easily in soil for over 5 years, than do the large or flat seeds. However, some large-seeded species also have the potential to establish short-term persistence bank. A literature survey reveals 88 % of the alpine seeds have a mass < 3 mg. Seed size has only a weak relationship with mean germination timing (MGT) indicating that reduced persistence in large-seeded species cannot be counteracted by quicker germination, but combined effects of other factors stimulating germination remain an open area to be studied. It is proposed that long distance dispersal (LDD) is limited in most-but not all-species, primarily due to the absence of specialized dispersal structures. However, among numerous dispersal modes, most species tend to be dispersed by wind. Thus, spermatophytes of alpine environments have a greater tendency to establish seed banks and spread the risk of germination to many years, rather than being dispersed to other micro-climates.