Diversity and Evolution in the shoot organization of Thymelaeaceae

通过形态和分子系统发育分析，阐明了百里香科植物枝条组织的多样性和进化。调查了该科20种植物，其中包括日本本土的5个属和菊属、丝虫属、丝兰属、水青兰属。经聚合酶链式反应扩增后，用自动测序仪分析叶绿体DNA上matK基因的核苷酸序列。根据matK基因的序列数据构建了系统发育树。树的配置与目前的百里香科系统不一致，建议对系统进行修改。通过对枝条组织的观察，发现三叉枝为顶芽，侧枝为侧枝。瑞香属植物存在两种不同的系统发育类型，即短花枝互生，长营养枝相反。在瑞香族中，头状花序，末叶有明显的腋芽，被认为是不对称的，而松散的花序可能是不对称的。

Morphological and molecular phylogenetic examinations were made to elucidate diversity and evolution of the shoot organization of the family Thymelaeaceae. 20 species of the family, including of the five Japanese indigenous genera and of the genera Dais, Gnidia, Daphnopsis, Aquilaria, were examined. The nucreotide sequences of the matK gene on the chloroplast DNA were analyzed with an autosequencer afrter amplified with PCR. A phylogenetic tree was constracted on the bases of the sequence data of the matK gene. The configulation of the tree was not in accordance with current system of Thymelaeaceae and suggests that the system should be revised. As the results of the examination on the shoot organization, the trichotomous branches of Edgeworthia were revealed to be a terminal shoot and its rateral branches. It was also found that there are different two phylotaxy in Daphne genkwa, i.e. alternate in the short flowering branches and opposite in the long vegetative branches. In the tribe Daphneae, the head like infloerescence with an distinct axillary bud at the ultimate leaf is considered to be plesiomorphic and the loose inflorescence of Diplomorpha may be apomorphic.