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。对植物来说，种子发芽的时间决定了个体能否生存和繁殖。发芽的时间也影响种群能否在特定环境中生存。在有利的条件下，许多植物利用温度、日照长度和土壤湿度等线索来确定发芽的时间。因此，这些线索的物种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，它们会继续进化吗？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？研究小组将在加利福尼亚植物区（CFP）内的地中海气候中解决这些问题。CFP是一个气候变率高的生物多样性热点地区。本研究将探讨在一组本地CFP野花物种中发芽对环境线索的反应是如何进化的。为此，研究小组将结合温室实验、基因组研究和比较分析。该项目将使用历史收集的数据并开发模型来了解这些过程如何塑造这些物种在整个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影响植物的生命周期。这将有助于深入了解驱动性状进化、种群持久性和物种分布的力量。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。研究小组将调查链菊属植物（宝石花）萌发时间的功能、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体适应性的影响。他们将评估这些模式是如何在整个团队中进化的，并评估过去和未来进化的可能约束。最后，将开发一个基于过程的模型，该模型将这些机制集成到一系列环境条件下的生活史时间预测中。这个新模型将被纳入现有的预测种群持久性和物种分布的人口统计学模型中。总之，本研究整合了生物多样性的三个维度：驱动生命史对线索反应的性状的功能多样性；基因组变异的多样性，以及差异和约束在链蕨枝-了解生活史时间的演变，以及如何变化的响应环境线索将影响种群持久性和物种分布的生态功能。该奖项反映了美国国家科学基金会的法定使命，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.