Briones Ortiz Bryan A, Boardman Fiona C, Ruesink Jennifer L, Naish Kerry A
School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, USA.
Department of Biology, University of Washington, Seattle, Washington, USA.
Mol Ecol. 2025 Apr;34(8):e17730. doi: 10.1111/mec.17730. Epub 2025 Mar 20.
Diversity in life expectancy is common in flowering plants. In the seagrass Zostera marina , a vital foundation species in estuarine ecosystems, annual and perennial varieties occur in close proximity, raising the question of whether these lifespan strategies represent locally adapted genetic variation or plastic phenotypes influenced by the environment. Our study combined field transplant experiments and population genetic analyses to investigate the phenotypic (juvenile survival, flowering, and branching) and genetic differentiation between paired annual and perennial eelgrass meadows in a single estuary (Willapa Bay, northeast Pacific Ocean, USA) over one growing season. A common garden reciprocal transplant experiment, based on seedlings, demonstrated no differential survival to maturity but revealed a greater likelihood of flowering in annual-sourced plants and branching in perennial-sourced shoots. Further, reproductive trait performance was greater for local individuals compared to non-local ones, which indicates adaptive differentiation. Experimental transplants of annual-sourced seeds into both annual and perennial-dominated sites flowered within a few months, regardless of overwintering conditions. Estimates of population structure based on 325 SNPs (RAD-seq) revealed fine-scale population structure between life history types. Population assignment tests identified two distinct groups, distinguished mainly by whether the seedling flowered or not, regardless of geographic source or outplant location. Tests for outlier loci between the two life histories provided further evidence of local adaptation. These insights shed light on the factors governing life cycle variation and resilience in Z. marina , offering implications for the evolution and trait-based management of eelgrass populations.
开花植物的预期寿命存在差异很常见。在海草大叶藻（Zostera marina）中，这是河口生态系统中的一种重要基础物种，一年生和多年生品种在近距离内共存，这就引发了一个问题：这些寿命策略是代表局部适应的遗传变异，还是受环境影响的可塑性表型。我们的研究结合了田间移植实验和群体遗传学分析，以调查在一个生长季节内，美国东北太平洋威拉帕湾（Willapa Bay）一个河口内成对的一年生和多年生鳗草草地之间的表型（幼体存活、开花和分枝）和遗传分化。一项基于幼苗的共同园圃相互移植实验表明，成熟前的存活率没有差异，但发现一年生来源的植株开花的可能性更大，多年生来源的嫩枝分枝的可能性更大。此外，与非本地个体相比，本地个体的繁殖性状表现更好，这表明存在适应性分化。将一年生来源的种子实验性移植到一年生和多年生为主的地点，无论越冬条件如何，几个月内都会开花。基于325个单核苷酸多态性（RAD-seq）的群体结构估计揭示了生活史类型之间的精细尺度群体结构。群体归属测试确定了两个不同的群体，主要区别在于幼苗是否开花，而与地理来源或移栽地点无关。两种生活史之间的异常位点测试提供了局部适应的进一步证据。这些见解揭示了控制大叶藻生命周期变异和恢复力的因素，对鳗草种群的进化和基于性状的管理具有启示意义。
