University of Leicester, Department of Biology, Leicester, UK.
Heredity (Edinb). 2013 Feb;110(2):105-10. doi: 10.1038/hdy.2012.98. Epub 2012 Dec 5.
Chromosome counts of plants grown from open-pollinated seed from Japanese knotweed around the world have revealed the presence of extensive hybridisation with both native and other introduced taxa. These hybrids fit into three categories: inter- and intraspecific hybrids involving the taxa of Fallopia section Reynoutria (giant knotweeds), hybrids between Japanese knotweed and F. baldschuanica (Regel) Holub and hybrids between Japanese knotweed and the Australasian endemics of the genus Muehlenbeckia. In this minireview, the viability of the different classes of hybrid and the potential threats they pose are discussed in the context of recent examples of allopolyploid speciation, which generally involve hybridisation between a native and an alien species. Such wide hybridisations also challenge accepted taxonomic classifications. Japanese knotweed s.l. provides a fascinating example of the interplay between ploidy level, hybridisation and alien plant invasion. The octoploid (2n=88) Fallopia japonica var. japonica (Houtt.) Ronse Decraene is a single female clone throughout much of its adventive range, and provides an ideal system for investigating the potential for wide hybridisation.
从世界各地的日本虎杖的开放授粉种子中生长的植物的染色体计数显示，与本地和其他引入的分类群之间存在广泛的杂交。这些杂种分为三类：涉及 Fallopia 节 Reynoutria（巨型虎杖）分类群的种间和种内杂种、日本虎杖和 F. baldschuanica（Regel）Holub 之间的杂种以及日本虎杖和属 Muehlenbeckia 的澳大拉西亚特有种之间的杂种。在这篇小综述中，讨论了不同杂种类别的活力及其构成的潜在威胁，这些威胁是在最近的异源多倍体物种形成的例子的背景下讨论的，这些例子通常涉及本地和外来物种之间的杂交。这种广泛的杂交也对公认的分类学分类提出了挑战。日本虎杖 s.l. 提供了一个有趣的例子，说明了倍性水平、杂交和外来植物入侵之间的相互作用。八倍体（2n=88）的日本虎杖 var. japonica（Houtt.）Ronse Decraene 在其大部分外来分布区都是单一的雌性克隆，为研究广泛杂交的潜力提供了一个理想的系统。
