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Molecular phylogeny and comparative ecology of Mexican Stevia

墨西哥甜叶菊的分子系统发育和比较生态学

基本信息

批准号：
07041129
负责人：
YAHARA Tetsukazu
金额：
$ 5.7万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

Mexican Stevia includes about 100 species of annual, perennial, and shrubs among which shurubby species are considered to be ancestral. Floral morphology is diversified among species. Autogamy and apomixis are found in many species. Chromosome numbers vary from n=11 to n=12.The goal of this project is to examine correlation in generation time, reproductive system, floral morphology and chromosome numbers. To obtain research materials, we carried out field trips in Mexico.In 1995, we had field trips in Oaxaca, Veracruz, Jalisco and some other states. We collected about 50 species of Stevia including Stevia phlebophyla and S.karwinskyana which had never been collected during the past hundred years and had been considered to be extinct. We also found several new species. In 1996, we had field trips to Chiapas, Chihuahua, Durango and some other northern states. As a result of field trips during the two years, we obtaiened materials of approximately 80 species of the 100 total. Chromosome counts made on these materials revealed that shrubby species have n=12, perennial species have n=12 or 11, and annual species have n=11 or 4 (in S.ephemera). This fact supports the idea that chromosome number reduction is associated with reduction in generation time. All materials of shrubs and annuals examined were sexual diploids while perennial plants are often triploids, tetraploids or pentaploids and are regarded as seed apomicts.As a result of a phylogenetic study using sequences of matK,Carphocaete (n=12) was shown to be a sister genus of Stevia. Another study using sequences of ITS revealed that shurubby species (n=12) are monophyletic and basal in the genus ; perrenial species belong to two monophyletic groups, one of which includes S.deltoidea (n=12) and S.decummbens (n=12), and the other includes some species with n=11 and S.origanoides (n=11,12).

墨西哥甜菊包括约100种一年生、多年生和灌木，其中灌木属被认为是祖先。花的形态在物种之间是多样化的。自花受精和无融合生殖存在于许多物种中。染色体数目从n=11到n= 12不等。本项目的目的是研究世代时间、生殖系统、花形态和染色体数目之间的相关性。为了获得研究材料，我们在墨西哥进行了实地考察，1995年，我们在瓦哈卡、韦拉克鲁斯、哈利斯科和其他一些州进行了实地考察。我们收集了近50种甜叶菊，包括Stevia phlebophyla和S.karwinskyana，这些甜叶菊在过去的一百年里从未被收集过，并且被认为已经灭绝。我们还发现了几个新物种。1996年，我们实地考察了恰帕斯州、奇瓦瓦州、杜兰戈州和其他一些北方州。由于这两年的实地考察，我们获得了总共100种中约80种的材料。对这些材料进行的染色体计数显示，灌木状物种的n=12，多年生物种的n=12或11，一年生物种的n=11或4（在S.蜉蝣）。这一事实支持了染色体数目减少与世代时间减少有关的观点。所有的灌木和一年生植物材料被检查的有性二倍体，而多年生植物往往是三倍体，四倍体或五倍体，被认为是种子无融合生殖体。利用ITS序列分析发现，Shurtenae种（n=12）在该属中为单系基部类群; Perrenial种属于两个单系类群，一个类群包括S.deltoidea（n=12）和S. decumbens（n=12），另一个类群包括S.origanoides（n = 11，12）和S.