Department of Biological Sciences, Clemson University, Clemson, SC, USA.
Departamento de botánica, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Concepción, Chile.
Proc Biol Sci. 2024 Jan 10;291(2014):20231519. doi: 10.1098/rspb.2023.1519.
Inadequate pollen receipt limits flowering plant reproduction worldwide. Ecological causes of pollen limitation (PL), like pollinator scarcity and low plant abundance, have been a primary research focus. The genetic diversity of plant populations could impact both quantity and quality components of PL in concert with ecological factors, yet empirical examples are lacking. We evaluated joint effects of ecological factors (flower abundance, pollinator visitation) and genetic effective population size () on PL across 13 populations of the common herb . We used a histological approach with 5504 styles from 1137 flowers to separate quantity and quality components of PL, and link these to reproductive output. and pollinator visitation interacted to shape PL, but had stronger direct effects. Effectively smaller populations experienced stronger quantity PL, and controlled crosses in a pollinator-free environment revealed that stigmatic pollen quantity was an intrinsic population-level attribute that increased with . Pollinator visitation enhanced pollen quality, but only in effectively larger populations. Quantity and quality PL negatively impacted fruit and seed set, respectively. Results highlight that PL is dictated by plant population genetic diversity in addition to commonly evaluated ecological factors. Efforts to support pollinators will more strongly enhance plant reproduction in genetically diverse populations.
授粉不足限制了开花植物在全球范围内的繁殖。授粉限制（PL）的生态原因，如传粉者的缺乏和植物丰度低，一直是主要的研究重点。植物种群的遗传多样性可能会与生态因素一起影响 PL 的数量和质量组成，但缺乏经验证据。我们评估了生态因素（花的丰度、传粉者访问）和遗传有效种群大小（Ne）对 13 个常见草本植物种群的 PL 的联合影响。我们使用组织学方法，对 1137 朵花中的 5504 个柱头进行分析，以分离 PL 的数量和质量组成，并将其与繁殖输出联系起来。Ne 和传粉者访问相互作用影响 PL，但 Ne 的直接影响更强。有效较小的种群经历更强的花粉数量 PL，并且在没有传粉者的环境中进行的控制杂交表明，柱头花粉数量是一个内在的种群水平属性，随着 Ne 的增加而增加。传粉者访问提高了花粉质量，但仅在有效较大的种群中。花粉数量和质量 PL 分别对果实和种子的形成产生负面影响。结果表明，PL 不仅由通常评估的生态因素决定，还由植物种群遗传多样性决定。支持传粉者的努力将在遗传多样性更高的种群中更有力地促进植物繁殖。
