Stout Jane C, Duffy Karl J, Egan Paul A, Harbourne Maeve, Hodkinson Trevor R
School of Natural Sciences and Trinity Centre for Biodiversity Research, Trinity College Dublin, Dublin 2, Ireland
School of Natural Sciences and Trinity Centre for Biodiversity Research, Trinity College Dublin, Dublin 2, Ireland School of Life Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa.
AoB Plants. 2014 Dec 19;7:plu087. doi: 10.1093/aobpla/plu087.
Populations of introduced species in their new environments are expected to differ from native populations, due to processes such as genetic drift, founder effects and local adaptation, which can often result in rapid phenotypic change. Such processes can also lead to changes in the genetic structure of these populations. This study investigated the populations of Rhododendron ponticum in its introduced range in Ireland, where it is severely invasive, to determine both genetic and flower width diversity and differentiation. We compared six introduced Irish populations with two populations from R. ponticum's native range in Spain, using amplified fragment length polymorphism and simple sequence repeat genetic markers. We measured flower width, a trait that may affect pollinator visitation, from four Irish and four Spanish populations by measuring both the width at the corolla tip and tube base (nectar holder width). With both genetic markers, populations were differentiated between Ireland and Spain and from each other in both countries. However, populations displayed low genetic diversity (mean Nei's genetic diversity = 0.22), with the largest proportion (76-93 %) of genetic variation contained within, rather than between, populations. Although corolla width was highly variable between individuals within populations, tube width was significantly wider (>0.5 mm) in introduced, compared with native, populations. Our results show that the same species can have genetically distinct populations in both invasive and native regions, and that differences in floral width may occur, possibly in response to ecological sorting processes or local adaptation to pollinator communities.
由于遗传漂变、奠基者效应和局部适应等过程，新环境中引入物种的种群预计会与本地种群有所不同，这些过程通常会导致快速的表型变化。此类过程还可能导致这些种群的遗传结构发生改变。本研究调查了在爱尔兰引入范围内严重入侵的杜鹃（Rhododendron ponticum）种群，以确定其遗传多样性和花宽多样性及分化情况。我们使用扩增片段长度多态性和简单序列重复遗传标记，将爱尔兰的六个引入种群与来自西班牙杜鹃原生范围的两个种群进行了比较。我们通过测量四个爱尔兰种群和四个西班牙种群的花冠顶端宽度和管基部宽度（花蜜容纳处宽度）来测定花宽，这一性状可能会影响传粉者的访花情况。使用这两种遗传标记时，爱尔兰和西班牙的种群之间以及两国各自的种群之间都存在分化。然而，种群显示出较低的遗传多样性（平均奈氏遗传多样性 = 0.22），遗传变异的最大比例（76 - 93%）存在于种群内部而非种群之间。尽管种群内个体间的花冠宽度变化很大，但引入种群的管宽比原生种群显著更宽（>0.5毫米）。我们的结果表明，同一物种在入侵区域和原生区域可能具有遗传上不同的种群，并且花宽可能会出现差异，这可能是对生态分选过程或对传粉者群落的局部适应的响应。
