Taxodiaceae - its systematics and characteristics of species

1.目的对杉木科15个物种和1个推测的杂交品种进行研究，目的是：(1)通过对杉木科植物cpDNA基因的RFLP分析，对杉木科植物进行系统分类；(2)结合生态学、生态生理学和群体遗传学的方法，明确杉木科植物的特征；(3)根据(1)和(2).2的研究结果，明确杉木与其他杉木科植物的系统发育关系。(1)物种的分子分类：叶绿体基因组基因的RFLP分析。(2)物种生态特征研究：环境因子调查；植被分析；并积累生态研究的报告和其他文件。(3)本种生态生理特性研究：各种光合作用和蒸腾作用分析。(4)群体遗传调查：核DNA、cpDNA和mtDNA的同工酶分析和RFLP分析。(5)综合以上结果，了解杉属植物在紫杉科系统发育中的地位。结果与讨论(1)杉木科系统研究利用pcr扩增的6个叶绿体基因的RFLP对杉木科所有树种针叶树的分子系统发育进行了研究。采用Wagner简约法和邻接法（NJ）得到了相似的基本简约树。柏科和杉木科是亲缘关系密切的科，而verticillata是柏科和杉木科的基系。(2)物种特征利用12种同工酶测定了日本杉木自然居群的遗传多样性。物种内的遗传变异量很大，但大多数是在种群内发现的，种群间的遗传变异很少，尽管它们是孤立分布的。这种遗传多样性的模式被推断为下列结果：该物种在过去的分布比现在更广泛和更连续；基因流动率高；寿命也很长。此外，我们还发现了黄花香自然居群的rDNA变异模式。种群内rDNA变异较大，种群内变异各不相同。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