Integrated Study on Evolution of genus Nicotiana (Solanaceae)

在这个分类学和生物地理学的研究项目中，我们挑战了一种新的方法。到目前为止，这些领域的研究通常是同时处理多个植物类群，而我们主要针对一个有代表性的植物类群，分析了物种划分的进化机制和分布的变化。我们选择了烟草属的野生型植物作为我们新方法的对象。烟叶属属于茄科，约有70种。烟叶的自然分布局限于南半球，在南美洲有37种，在澳大利亚有20种，在非洲有1种。我们调查了南美洲玻利维亚和阿根廷以及大洋洲澳大利亚、新喀里多尼亚和新西兰的烟叶属野生型种。首先，作为分类学的结果，我们在南美洲发现了一种烟草属的新种。我们用分子系统发育和生理方法对该植物进行了分析。其次，用生物地理学方法分析了该属10种植物的分布变化。这项分析的结果是，至少有两个物种，烟叶（Nicotiana acaulis）和ikawakamii已经处于灭绝的边缘。第三，我们获得了烟草植物（Nicotiana tabacum）起源的系统发育结果。烟叶被认为是两二倍体植物。虽然许多研究表明，烟粉虱的母种是nn .sylvestris，但父系种是未知的。我们的分析表明，父系物种的植物可能已经灭绝了。研究还停留在刚开始的时候。为了证实这些结果，需要进行进一步的分析。

In this project of the study of taxonomy and biogeography, we have challenged a new approach. Thus far, studies of these fields usually treated many taxa of plants at once, while we focused on a representative group of plants and analyzed the evolutionary mechanism of division of speciation and the change of the distribution. We chose the wild-type plants of the genus Nicotiana as the object of our new approach. The genus Nicotiana belongs to Solanaceae and contains about 70 species. The natural distribution of Nicotiana is limited to Southern Hemisphere. 37 species of this genus occur in South America, 20 species in Australia, and a species in Africa. We investigated wild-type species of the genus Nicotiana in Bolivia and Argentina in South America and Australia, New Caledonia, and New Zealand in Oceania. First, as the result of taxonomy we discovered a novel species of the genus Nicotiana in South America. We analyze this plant using molecular phylogenetic and physiological methods. Secondly, we analyzed the change of distribution of some ten species of this genus using the biogeographical method. The result of this analysis is that at least two species, Nicotiana acaulis and N.Ikawakamii has been on the verge of extinction. Thirdly, we have obtained the phylogenetic results that show the origin of tobacco plants (Nicotiana tabacum). N.tabacum is thought to be amphidiploid plants. Although many studies exhibited that the maternal species of N.tabacum is N.sylvestris, the paternal species is unknown. Our analysis indicated that the plants of the paternal species might have been extinct. Research has still been attached to the start just. The further analysis is required in order to confirm these results.