特征对于理解植物群落如何组装和功能很重要,为研究跨物种的生态过程提供了一种共同的货币,地点,和栖息地类型。然而,大多数将物种性状与群落组装相关的研究都依赖于成熟植物的营养性状。种子性状,相对于整个植物的性状,是理解植物群落组装的关键。对于恢复的社区来说尤其如此,通常从种子开始,使种子发芽成为群落组装的关键第一步,也是植物建立的早期过滤器。我们通过实验测试了种子性状(质量,形状,和胚胎与种子大小之比)以及系统发育对美国中西部草原恢复中常用的32种物种的发芽反应的影响,使用事件时间(生存)分析来分析数据。由于发芽也受到种子休眠的影响,休眠中断治疗通常用于修复,我们还测试了两种预处理(冷分层和赤霉酸施用)对发芽时间的影响。种子性状,系统发育,和种子预处理都影响发芽时间。在所有测试的特征中,与种子形状相关的变量(高度和形状方差)最佳预测发芽反应,具有高方差(即,更尖,更窄)种子发芽更快。系统发育位置(物种在系统发育树上相对于其他测试物种的位置)也是发芽反应的重要预测因子,也就是说,密切相关的物种在发芽时间上表现出相似的模式。尽管所有测量的种子性状都显示出系统发育信号,因此,系统发育提供了尚未被测量的种子性状捕获的残留信息。种子性状,系统发育位置,和发芽预处理是一系列常用于草地恢复的物种的发芽响应的重要预测因子。形状特征尤其重要,虽然质量,通常是社区组装研究中使用的唯一种子性状,不是发芽时间的强预测因子。这些发现说明了种子性状的生态重要性,这些性状很少被纳入植物群落的功能研究。此信息还可用于通过指导恢复计划和种子混合设计来推进恢复实践。
Traits are important for understanding how plant communities assemble and function, providing a common currency for studying ecological processes across species, locations, and habitat types. However, the majority of studies relating species traits to community assembly rely upon vegetative traits of mature plants. Seed traits, which are understudied relative to whole-plant traits, are key to understanding assembly of plant communities. This is particularly true for restored communities, which are typically started de novo from seed, making seed germination a critical first step in community assembly and an early filter for plant establishment. We experimentally tested the effects of seed traits (mass, shape, and embryo to seed size ratio) and phylogeny on germination response in 32 species commonly used in prairie grassland restoration in the Midwestern USA, analyzing data using time-to-event (survival) analysis. As germination is also influenced by seed dormancy, and dormancy break treatments are commonly employed in restoration, we also tested the effects of two pretreatments (cold stratification and gibberellic acid application) on time to germination. Seed traits, phylogeny, and seed pretreatments all affected time to germination. Of all traits tested, variables related to seed shape (height and shape variance) best predicted germination response, with high-variance (i.e., pointier and narrower) seeds germinating faster. Phylogenetic position (the location of species on the phylogenetic tree relative to other tested species) was also an important predictor of germination response, that is, closely related species showed similar patterns in time to germination. This was true despite the fact that all measured seed traits showed phylogenetic signal, therefore phylogeny provided residual information that was not already captured by measured seed traits. Seed traits, phylogenetic position, and germination pretreatments were important predictors of germination response for a suite of species commonly used in grassland restoration. Shape traits were especially important, while mass, often the only seed trait used in studies of community assembly, was not a strong predictor of germination timing. These findings illustrate the ecological importance of seed traits that are rarely incorporated into functional studies of plant communities. This information can also be used to advance restoration practice by guiding restoration planning and seed mix design.