Graduate School of Human and Environmental Studies, Kyoto University, Yoshida Nihonmatsu-cho, Sakyo-ku, Kyoto 606-8501, Japan.
J Plant Res. 2011 Jan;124(1):75-83. doi: 10.1007/s10265-010-0356-z. Epub 2010 Jun 12.
Japanese horse chestnut (Aesculus turbinata: Hippocastanaceae) is one of the typical woody plants that grow in temperate riparian forests in the Japanese Archipelago. To analyze the phylogeography of this plant in the Japanese Archipelago, we determined cpDNA haplotypes for 337 samples from 55 populations covering the entire distribution range. Based on 1,313 bp of two spacers, we determined ten haplotypes that are distinguished from adjacent haplotypes by one or two steps. Most of the populations had a single haplotype, suggesting low diversity. Spatial analysis of molecular variance suggested three obvious phylogeographic structures in western Japan, where Japanese horse chestnut is scattered and isolated in mountainous areas. Conversely, no clear phylogeographic structure was observed from the northern to the southern limit of this species, including eastern Japan, where this plant is more common. Rare and private haplotypes were also found in southwestern Japan, where Japanese horse chestnuts are distributed sparsely. These findings imply that western Japan might have maintained a relatively large habitat for A. turbinata during the Quaternary climatic oscillations, while northerly regions could not.
日本七叶树（Aesculus turbinata：七叶树科）是一种典型的木本植物，生长在日本群岛的温带河畔森林中。为了分析该植物在日本群岛的系统地理学，我们对来自 55 个种群的 337 个样本的 cpDNA 单倍型进行了测定，这些种群的分布范围覆盖了整个分布范围。基于两个间隔区的 1,313bp，我们确定了 10 种单倍型，它们与相邻的单倍型有一个或两个步骤的区别。大多数种群只有一个单倍型，表明多样性较低。分子方差的空间分析表明，在日本西部有三个明显的系统地理学结构，日本七叶树在那里分散和孤立在山区。相比之下，在包括日本东部在内的该物种分布更为普遍的北部到南部界限上，没有明显的系统地理学结构。在日本西南部，也发现了稀有和特有单倍型，那里的日本七叶树分布稀疏。这些发现表明，在第四纪气候波动期间，日本西部可能为 A. turbinata 维持了一个相对较大的栖息地，而北部地区则不能。
