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Studies on the extinction and conservation of plant species diversity

植物物种多样性灭绝与保护研究

基本信息

批准号：
08554035
负责人：
IWATSUKI Kunio
金额：
$ 7.42万
依托单位：
RIKKYO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

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

目前对植物物种多样性的灭绝和保护的研究取得了以下成果： 1.确定植物体内的实际扩散对于保护灭绝和保护其遗传多样性具有重要意义。进行电泳分析来检查自由孢子蕨 Pteris multifida 种群的遗传结构。结果表明，蕨类植物虽然具有较高的传播能力，但其孢子传播受到很大限制。2.对世界范围内濒临灭绝的形态和生态特异水草——波多斯特马科(Podostemaceae)进行了发育形态学研究。在 Malaccotristicha malayana 中，匍匐轴与根同源，因为它具有根冠，并且侧根内生于母根的维管柱附近。该物种在形态上比 Indotnsticha ramosissima 和 Tristicha trifaria 更加特化，后者是该科中最不特化的物种。3.最近我们在芦之湖发现了 Nitella gracilens，人们认为这种细菌在日本已经灭绝。为了检查藻类的分类位置，通过扫描电子显微镜观察卵孢子壁的装饰。我们的结果支持了这种藻类是日本特有的观点。4.对马桑属进行了分子系统发育分析。所获得的树并不支持大陆漂移导致该属目前不连续分布的假设，但表明这种分布模式可能是第三纪末期扩散和灭绝的结果。 5.化石数据表明，宏碁属在其历史上重复出现了物种形成和灭绝。为了为物种灭绝提供基础数据，我们分析了宏碁的分子系统发育并评估了叶绿体DNA的进化速率。我们的结果表明，东亚和北美的双角物种分离在中新世晚期出现了分化，东亚和北美植物区系的相似性是由于物种群体的多次扩散、分离和灭绝造成的。较少的