Department of Biological Sciences, Clemson University, Clemson, South Carolina 29634, USA.
Am J Bot. 2011 Jul;98(7):1128-38. doi: 10.3732/ajb.1000297. Epub 2011 Jun 10.
Invasive plants often display genetically determined variation in patterns of growth and resource allocation between native and introduced genotypes, as well as among genotypes within different regions of the introduced range. We examined patterns of genetic variation within and among native and introduced populations of the tetraploid Chinese tallow tree (Triadica sebifera, Euphorbiaceae) to determine whether nonselective evolutionary processes or the introduction history could contribute to previously observed phenotypic differences between native and introduced populations as well as among introduced populations.
We used six microsatellite markers to study 12 native populations in China, 51 introduced populations in the southeastern USA, and one introduced population in Australia.
Genetic diversity was greater within and among native populations than introduced populations. Within the southeastern USA, populations in Georgia and South Carolina differed substantially in their genetic composition and had greater genetic diversity than the rest of the southeastern USA. Greater genetic similarity between some populations in the native range and introduced range indicate a common provenance for Georgia and South Carolina populations that could have come from any of several western or southern Chinese populations and a different provenance for other southeastern USA populations and the Australian population, which were most similar to more northeastern Chinese populations.
Differences among introduced populations in potentially adaptive traits (e.g., herbivore tolerance, herbivore resistance, growth rates) may result in part from the introduction history, in particular from differences present among source populations in the native range.
入侵植物通常在生长模式和资源分配方面表现出由遗传决定的变化，这种变化既存在于原生和引入基因型之间，也存在于引入范围不同地区的基因型之间。我们研究了四倍体中国乌桕（Triadica sebifera，大戟科）的原生和引入种群内部以及种群之间的遗传变异模式，以确定非选择性进化过程或引入历史是否有助于解释先前观察到的原生和引入种群之间以及引入种群之间的表型差异。
我们使用了 6 个微卫星标记来研究中国的 12 个原生种群、美国东南部的 51 个引入种群和澳大利亚的一个引入种群。
与引入种群相比，原生种群内部和种群之间的遗传多样性更大。在美国东南部，佐治亚州和南卡罗来纳州的种群在遗传组成上有很大差异，遗传多样性也比东南部其他地区的种群更大。原生范围和引入范围的一些种群之间具有更大的遗传相似性，表明佐治亚州和南卡罗来纳州的种群可能有共同的起源地，可能来自中国西部或南部的几个种群，而其他美国东南部种群和澳大利亚种群的起源地则不同，它们与中国东北部的种群更为相似。
引入种群在潜在适应性特征（如食草动物耐受性、抗食草动物性、生长速度）方面的差异可能部分是由于引入历史，特别是由于原生范围的来源种群之间存在差异。
