Evolutionary Study of Rheophytic Family Podostemaceae

1. 为了阐明极为特殊的水生被子植物家族的系统发育和形态进化，在斯里兰卡进行了实地考察。印度、泰国。北美。墨西哥，圭亚那和巴西。通过使用旅行中收集的材料，进行了以下调查。基于matK核苷酸序列进行了分子系统发育分析。所获得的树显示，Weddellina属属于Tristichoideae亚科，是Podostemoideae亚科的基础，表明迄今为止识别的亚科是一个副aphyletic分类单元。澳大利亚东北部特有的Torrenticola接近亚洲的Cladopus。虽然Dalzella和Indotristicha在形态上有显著差异，但它们彼此接近。此外，经检查的旧大陆属形成一个集群。本文对三鳃蝇亚科中最基础的属Malaccotristicha malayana和Podostemoideae亚科中最特化的属Hydrobryum japonicum进行了发育形态学和解剖学研究。马拉亚纳的匍匐轴与根同源。日本水螅（Hydrobryum japonicum）的叶状花序表现出一种特殊的、不连续的分生组织发育，这产生了日本水螅特有的不规则的分叶体。

1. For elucidating the phylogeny and morphological evolution of the extremely specialized aquatic angiosperm family, field trips were made in Sri Lanka. India, Thailand. North America. Mexico, Guyana, and Brazil. By using materials that were collected during the trips, the following investigations were performed.2. A molecular phylogenetic analysis based on matK nucleotide sequences was made. The trees obtained show that the genus Weddellina, which has been referred to the subfamily Tristichoideae, is basal in the other subfamily Podostemoideae, indicating that the subfamily recognized so far is a paraphyletic taxon. The Torrenticola endemic to NE Australia is close to the Asian Cladopus. Although Dalzella and Indotristicha remarkably differ from each other morphologically, they are close to each other. Furthermore, the Old World genera examined make a cluster.3. Developmental morphological and anatomical studies were made of Malaccotristicha malayana the most basal genus in the subfamily Tristichoideae, and Hydrobryum japonicum, a most specialized genus in the subfamily Podostemoideae. The creeping axis of Malaccotristicha malayana is homologous with the root. The foliose Hydrobryum japonicum exhibits a peculiar, discontinuous development of the meristem, which gives rise to irregularly lobed thalli specific to Hydrobryum japonicum.