PDF(Pubmed)
Abstract：
Seed germination and dispersal have an important impact on the establishment and spread of invasive plants. Understanding the extent of intraspecific seed trait variations can enhance our understanding of how invasive plants respond to environmental change after introduction and help predict the dynamic of invasive species under future environmental conditions. However, less attention has been given to the variation in seed traits within species as opposed to among species. We compared seed production, seed morphological traits, dispersal ability, and seedling performance of Chromolaena odorata from 10 introduced populations in Asia and 12 native populations in America in a common garden. The results showed that range (introduced vs. native) and climate affected these traits. Compared with the native population, the introduced populations had higher seed numbers per capitula, lighter seeds, and higher potential dispersal ability seeds (lower terminal velocity) but lower germination rates and seedling lengths. Climatic clines in seed numbers per capitula and pappus length were observed; however, the clines in pappus length differed between the introduced and native populations. Trait covariation patterns were also different between both ranges. In the native populations, there was a trade-off between seed numbers per capitula and seed mass, while this relationship was not found for the introduced populations. These results indicate that C. odorata alters the ecological strategy of seed following invasion, which facilitates its establishment and fast dispersal and contributes to successful invasion in the introduced ranges.
摘要：
种子的萌发和传播对入侵植物的建立和传播具有重要影响。了解种内种子性状变异的程度可以增强我们对入侵植物在引入后如何应对环境变化的理解，并有助于预测未来环境条件下入侵物种的动态。然而,与物种之间相比，种内种子性状的变化受到的关注较少。我们比较了种子产量，种子形态性状,分散能力，在一个普通的花园中，来自亚洲10个引种种群和美国12个本地种群的赤藻的幼苗性能。结果表明，范围(介绍与本地）和气候影响了这些特征。与当地人口相比，引入的种群每个头花有更高的种子数量，较轻的种子，和更高的潜在分散性种子（较低的终端速度），但发芽率和幼苗长度较低。观察到每个头花的种子数量和乳头长度的气候变化；但是，在引入种群和本地种群之间，papus长度的序列有所不同。两个范围之间的性状共变模式也不同。在当地人口中，每个头花的种子数量和种子质量之间存在权衡，而这种关系在引进的人群中没有发现。这些结果表明C.odorata改变了入侵后种子的生态策略，这有助于其建立和快速扩散，并有助于在引入的范围内成功入侵。
