Studies on the extinction and conservation of plant species diversity

本文对植物物种多样性的灭绝与保护进行了研究，结果如下：1.确定物种在植物体内的实际扩散，对于保护物种的灭绝和保护其遗传多样性具有重要意义。对自由孢子蕨类植物多裂蕨类植物群体的遗传结构进行了分析。结果表明，蕨类植物虽然具有较强的传播能力，但孢子的传播在很大程度上是有限的。2.对世界范围内濒危的形态和生态特化的水草--蒲公英进行了发育形态研究。在Malaccotristicha marayana中，爬行轴与根是同源的，因为它有一个根帽，侧根在母根的维管柱附近内源起始。该种在形态上比该科中专门化程度最低的印度文竹和三叶草更具专化性。3.最近我们是…。更多的人在Ashinoko湖发现了更多细小Nitella gracilens，这种Nitella gracilens曾被认为在日本已经灭绝。利用扫描电子显微镜观察卵孢子壁纹饰，以确定该藻类的分类地位。我们的结果支持该藻属为日本特有的观点。4.对马尾藻属进行了分子系统发育分析。得到的一棵树不支持大陆漂移参与了该属目前的分离分布的假说，但表明这种分布格局可能是第三纪末期扩散和灭绝的结果。5.传闻数据表明，在其历史上，枫属经历了物种形成和灭绝的重复。为了提供物种灭绝的基础数据，我们分析了宏的分子系统发育和叶绿体DNA的进化速率。我们的结果表明，东亚和北美的双变异种在中新世晚期分化，东亚和北美植物区系的相似性是物种群多次扩散、分离和灭绝的结果。较少

The present study on the extinction and conservation of plant species diversity had the following results :1.It is important to determine the actual dispersal in plants in order to protect extinction and make conservation of their genetic diversity. An electrophoretic analysis was performed to examine the genetic strcture of polulations in the free-spored fern Pteris multifida. The result suggested that although ferns have high dispersal ability, spore dispersal is limited to a great extent.2.A developmental morphological study was made of the morphologically and ecologically specialized water-weeds, Podostemaceae, which are endangered worldwide. In Malaccotristicha malayana, the creeping axis is homologous with a root, because it has a root-cap and the lateral root initiated endogenously near the vascular cylinder of the mother root. The species is morphologically more specialized than Indotnsticha ramosissima and Tristicha trifaria, the least specialized in the family.3.Recently we r … More ediscovered Nitella gracilens in Lake Ashinoko, which had been believed to beextinct from Japan. In order to examine the taxonomic position of the alga, the oospore wall ornamentation was observed by scanning electron microscopy. Our result supported the view that the alga is endemic to Japan.4.A molecular phylogenetic analysis of the genus Coriaria was performed. A obtained tree does not support the hypothesis that the continental drift was involved in the present disjunct distribution of the genus, but suggests that the distribution pattern may have resulted from dispersal and extinction at the end of the Tertiary.5.Fossil data suggest that the genus Acer had a repetition of speciation and extinction through its history. In order to make basic data to suggest species extionction, we analyzed the molecular phylogeny of Acer and evaluated the evolutionary rate of chloroplast DNA.Our results suggest that the bicariant species disjunct in eastern Asia and North America diverged in late Miocene, and that the similarity between eastern Asian and North American floras resulted from multiple dispersal, disjunction, and extinction of the species groups. Less