Ecological and evolutionary role of a persistent soil seed bank in perennial herbaceous plant species

植物已经发展出两种降低风险的机制，即分散和休眠，以应对其生境的不可预测性。理论模型表明，土壤种子库中休眠的种子对植物人口统计、遗传结构和进化生物学有许多特定的影响。因此，种子库可以增加或保护遗传多样性，减少种群分化。然而，关于种子库和地上种群之间遗传关系的经验数据很少。该项目将包括实地考察和普通园艺研究。根据之前自己研究的信息，它将重点放在Viola elatior Fries上，这是一种多年生草本植物，沿着从洪水平原草甸到冲积森林的环境梯度生长。主要目的是检验以下假设：(1)多年生植物中持久的土壤种子库是地上种群中不再存在的基因型的储存库，(2)种子休眠和萌发对不同选择制度的响应取决于亲本种群的遗传多样性，(3)自然和强制萌发的种子在萌发后特性和适合度上存在差异。我们将进行AFLP基因组扫描，以确定种子库和地上种群以及沿环境梯度的潜在适应基因座。此外，我们还将使用基于不同景观度量的景观遗传学方法来解决紫菜种群的遗传多样性和分化是否以及如何与周围的景观结构相关的问题。

Plants have developed two risk reduction mechanisms, dispersal and dormancy, to cope with the unpredictability of their habitats. Theoretical models suggest a number of specific effects of dormant seeds in a soil seed bank on plant demography, genetic structure and evolutionary biology. Thus, seed banks may increase or conserve genetic diversity and reduce population differentiation. However, empirical data on genetic relationships between seed bank and above-ground population are scarce. This project will consist of field and common garden studies. Based on information of previous own studies, it will focus on Viola elatior Fries, a perennial herb occurring along an environmental gradient from floodplain meadows to alluvial forests. The main aims are to test the hypotheses that (1) a persistent soil seed bank in a perennial plant serves as a reservoir of genotypes that are not longer present in the above-ground population, (2) variation in seed dormancy and germination in response to different selection regimes depends on the genetic diversity of the parent population and (3) that naturally and enforced germinating seeds differ in post-germination traits and fitness. We will do an AFLP genome scan to identify potentially adaptive loci in the seed bank and the above-ground population and along an environmental gradient. Additionally, we will address the question whether and how genetic diversity and differentiation of Viola elatior populations are related to the surrounding landscape structure using a landscape genetic approach based on different landscape metrics.