Dimensions: Diversity and constraint in the germination niche: Implications for persistence in a biodiversity hotspot

在一个不确定的世界里，时机就是一切。对于植物来说，种子发芽的时间决定了个体是否能够生存和繁殖。发芽的时间也影响种群是否能在特定环境中持续存在。许多植物利用温度、日照长度和土壤湿度等线索来确定有利条件下的发芽时间。因此，物种在这些线索上的差异可能决定了一个物种能够生存的气候条件。反过来，这些差异可以塑造它们在整个景观中的分布。这些线索的反应是如何演变的？ 如果环境发生变化，它们会继续发展吗？在当前和未来的条件下，这些模式如何决定物种的持久性和分布？研究小组将在加州植物区系省（CFP）的地中海气候中解决这些问题。CFP是一个生物多样性热点，其特征是强烈的气候变率。本研究将探讨如何发芽反应的环境线索已经演变成一组本地CFP野花物种。为此，该团队将使用温室实验，基因组研究和比较分析的组合。该项目将使用历史收集的数据并开发模型，以了解这些过程如何塑造这些物种在CFP中的分布。这些结果将有助于更深入地了解对环境线索的反应如何塑造植物生命周期。这将提供洞察力驱动性状进化，人口持久性和物种分布。作为活动的一部分，三名博士后学者，一名研究生和几名本科生将接受研究培训和指导。该研究小组将调查Streptanthus（珠宝花）组发芽时间的功能，遗传和系统发育多样性。首先，研究小组将描述整个群体对温度和湿度的发芽反应。其次，他们将确定驱动这些反应差异的候选基因和途径。接下来，他们将确定这些模式对个人健康的影响。他们将评估这些模式如何在整个群体中演变，并评估过去和未来演变的可能制约因素。最后，将开发一个基于过程的模型，将这些机制整合到一系列环境条件下的生活史时序预测中。这一新模型将被纳入现有的人口模型，用于预测种群持续性和物种分布。总之，这项研究整合了生物多样性的三个方面-功能多样性的特点驱动生活史的反应线索;基因组变异是链花属进化枝多样性、分歧和限制的基础--为了理解生活史时间的进化，以及对环境线索的反应变化将如何影响种群持久性和物种分布的生态功能。该奖项反映了NSF的基金会的使命是履行其法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In an uncertain world, timing is everything. For plants, the timing of seed germination determines whether individuals will survive and reproduce. The timing of germination also influences whether populations can persist in particular environments. Many plants use cues such as temperature, day length, and soil moisture to time germination during favorable conditions. Species differences in these cues may thus determine the climatic conditions in which a species can persist. In turn, these differences can shape their distribution across the landscape. How do responses of these cues evolve? Will they continue to evolve if the environment changes? How do these patterns determine species persistence and distribution under current and future conditions? The research team will address these questions in Mediterranean climates within the California Floristic Province (CFP). The CFP is a biodiversity hotspot characterized by strong climate variability. This research will investigate how germination responses to environmental cues have evolved in a group of native CFP wildflower species. To do so, the team will use a combination of greenhouse experiments, genomic studies, and comparative analyses. The project will use data from historical collections and develop models to understand how these processes shape the distribution of these species across the CFP. The results will contribute a deeper understanding of how responses to environmental cues shape plant life cycles. This will provide insight into the forces driving trait evolution, population persistence, and species distributions. As part of the activities, three postdoctoral scholars, a graduate student, and several undergraduate students will receive research training and mentorship. The research team will investigate functional, genetic, and phylogenetic diversity of germination timing in the Streptanthus (jewelflower) group. First, the research team will characterize germination responses to temperature and moisture across the group. Second, they will identify candidate genes and pathways that drive these differences in responses. Next, they will determine the consequences of those patterns for individual fitness. They will assess how those patterns have evolved across the group and evaluate possible constraints to past and future evolution. Finally, a process-based model that integrates these mechanisms into predictions of life history timing across a range of environmental conditions will be developed. This new model will be incorporated into existing demographic models for predicting population persistence and species distributions. Together, this research integrates three dimensions of biodiversity- functional diversity in traits driving life history responses to cues; genomic variation underlying that diversity, and divergence and constraint across the Streptanthus clade- to understand the evolution of the life history timing, and how variation in responses to environmental cues will influence the ecological function of population persistence and species distributions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.