Taxodiaceae - its systematics and characteristics of species

1.本研究对杉科15个种和1个杂种进行了研究，目的是：（1）利用cpDNA基因的RFLP分析进行杉科系统学研究;（2）综合运用生态学、生理生态学和群体遗传学方法，阐明杉科植物的特征;（3）根据（1）和（2）的研究结果，对杉属植物与杉科其他植物的系统发育关系有一个清晰的认识。种的分子分类：叶绿体基因组基因的RFLP分析。(2)物种生态特性之研究：环境因子调查、植被分析、生态研究报告及其他文献之累积。(3)树种生理生态特性研究：各树种光合作用和蒸腾作用分析。(4)群体遗传学调查：核DNA、cpDNA和DNA的同工酶分析和/或RFLP分析， ...更多信息 d线粒体DNA。(5)3.结果与讨论（1）杉科系统学我们利用PCR扩增的6个叶绿体基因的RFLP分析了杉科所有种的分子系统学。当应用瓦格纳简约法和邻接法时，数据集产生了相似的基本简约树。柏科和杉科是近缘科，而轮叶山杉是柏科和杉科的基底支系。（2）种的特征利用12种等位酶对日本杉天然居群的遗传多样性进行了分析。物种内的遗传变异量很高，但大多数是在种群内发现的，尽管它们孤立分布，但种群间的遗传变异很少。这种遗传多样性的模式被推断为以下的结果：该物种在过去的分布比现在更广泛，更连续;基因流动发生率高;寿命长。此外，我们还发现了自然群体中的rDNA变异模式。居群内的rDNA变异较高，且居群内的变异各不相同。少

1.PurposeThe purposes of this research program on fifteen species and one putative hybrid of Taxodiaceae are : (1) to make Taxodiaceae systematics by RFLP analysis on genes of cpDNA,(2) to clarify the characteristics of the species by means of ecological, ecophysiological, and population genetic methods in combination, and (3) to have clear understanding on phylogenetic relationship of sugi to other Taxodiaceae species based on the results of (1) and (2).2.Research items and research methods(1) Molecular classification on the species : RFLP analysis of genes on chloroplast genome.(2) Research on ecological characteristics of the species : investigation on environmental factors ; vegetational analysis ; and accumulating reports and other documents of ecological studies.(3) Research on ecophysiological characteristics of the species : analysis for photosynthesis and transpiration of each species.(4) Population genetic survey : Isozyme analysis and/or RFLP analysis on nuclear DNA,cpDNA an … More d mtDNA.(5) Integration of above results to have understanding on the phylogenetic position of sugi in Taxodiaceae systematics.3.Results and Discussion(1) Taxodiaceae systematicsWe have investigated a molecular phylogeny of conifer including all of Taxodiaceae species using RFLP of PCR-amplified six chloroplast genes. The data sets produced similar basic parsimonious trees when the Wagner parsimony and the neighbor-joining (NJ) methods were applied. Cupressaceae and Taxodiaceae are closed related families each other, and Sciadopitys verticillata is the basal lineage of Cupressaceae and Taxodiaceae(2) Characteristics of the speciesWe have determined the genetic diversity in natural populations of C.japonica using 12 allozymes. The amount of genetic variation within the species is high but most is found within populations with little among populations despite their isolated distribution. This pattern of genetic diversity is inferred to be the consequence of the following : the distribution of this species in the past was wider and more continuous than it is now ; a high rate of gene flow occurs ; and the long life span. Moreover we have found the mode of rDNA variation in natural populations of Sciadopitys verticillata. This species have a higher rDNA variation within population and the variations within populations are different from each other. Less