Studies on the extinction and conservation of plant species diversity

目前植物物种多样性灭绝与保护的研究主要有以下几个方面：1.确定植物的实际扩散程度对保护物种灭绝和保护其遗传多样性具有重要意义。采用电泳技术研究了多裂凤尾蕨（Pterismultifida）离体群体的遗传结构。结果表明，蕨类植物虽然具有很强的传播能力，但孢子传播能力有限。2.对世界濒危水生植物-- Malaccotristicha malayana的匍匐轴与根同源，因为它具有根冠，侧根在母根的维管圆柱附近内源发生。该种在形态上比多枝印度针蚁和特化程度最低的三裂针蚁更特化。 ...更多信息 他在芦之湖发现了被认为在日本已经灭绝的Nitella gracilens。为了探讨该菌的分类地位，用扫描电镜观察了卵孢子壁的外展。我们的结果支持了马桑属是日本特有种的观点。4.对马桑属进行了分子系统发育分析。该属的间断分布不支持大陆漂移的假说，而可能是第三纪末期的扩散和绝灭的结果。5.化石资料表明，槭属在其历史上经历了物种形成和绝灭的重复。通过对槭属植物的分子进化和叶绿体DNA进化速率的分析，认为东亚和北美分离的二变型种在中新世晚期发生了分化，东亚和北美植物区系的相似性是种群多次扩散、分离和绝灭的结果。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