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Speciation and taxonomy of the endemic family Aucubaceae in Sino-Japanese floristic region

中日植物区特有木珊瑚科的物种形成与分类

基本信息

批准号：
20770063
负责人：
TETSUO Ohi-Toma
金额：
$ 2.75万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Young Scientists (B)
财政年份：
2008
资助国家：
日本
起止时间：
2008 至 2010
项目状态：
已结题

项目摘要

Aucuba, the only genus in the family Aucubaceae, is endemic to the Sino-Japanese floristic region, and is diversified around southwestern China. In the genus 10 to 20 dioecious evergreen shrub or tree species were recognized, but there are taxonomic confusions because of quite variable characters. For the chromosome numbers, it is thought that A. japonica was the only polyploid complex in the genus. Our previous study based on chloroplast phylogeny indicated that tetraploidization occurred independently at least three times within A. japonica. It is possible that other species in China might include polyploids. In the present study, (1) to evaluate the chromosomal evolution, (2) to understand the speciation process of A. japonica, (3) to revise the classification of the genus , we conducted the phylogenetic analysis based on additional sequences of chloroplast DNA noncoding regions and nuclear DNA (ITS region and exon of GapC gene) and the flow cytometric analysis for several species obtained from China and its neighboring regions. Our results indicate that 1) the genus is divided into two lineages of shrub having dark purple flowers and tall-species having pale yellow flowers, 2) the traditional recognition of A. chinensis has been misinterpreted, and 3) several species were polyploids and most of them, including A. japonica, were originated by allopolyploidizatios

桃金娘是洋葱科独一属，为中日植物区特有，分布于中国西南部一带。在该属中有10-20种雌雄异株的常绿灌木或乔木，但由于特征差异很大，分类上存在混乱。从染色体数目来看，日本海棠是该属中唯一的多倍体复合体。我们先前基于叶绿体系统发育的研究表明，四倍体至少发生过三次。中国的其他物种可能包括多倍体。在本研究中，(1)为了评价染色体的进化，(2)为了了解日本海棠的物种形成过程，(3)为了修订该属的分类，我们根据从中国及其邻近地区获得的几个物种的叶绿体DNA非编码区和核DNA(GAPC基因的ITS区和外显子)的额外序列进行了系统发育分析，并进行了流式细胞仪分析。我们的结果表明：1)花为深紫色花的灌木和花为淡黄色花的高大种可分为两个谱系；2)传统的认识被曲解；3)几个种是多倍体的，其中大多数种是由异源多倍体起源的。