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Research on plant speciation with adaptive radiation in New Zealand.

新西兰适应性辐射植物物种形成研究。

基本信息

批准号：
16405013
负责人：
ITO Motomi
金额：
$ 8.38万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

One of the modes of speciation, an adaptive radiation is a speciation in which some species have derived from single ancestral species with ecological adaptation to diversified environments. This process generally has occurred within short times, and relatively small numbers of mutation could be responsible to large changes in their morphology and ecological characteristics. New Zealand has been isolated from the adjacent landmass by the ocean, and thus for the plants, it is very hard to migrate from the other landmass. New Zealand is located in high latitude, and in glacial ages, a large part of the land had been covered with glaciers. Thus, the flora of New Zealand is a good model for studying plant adaptive radiation. We examined the mode of speciation in New Zealand for Celmisia (Asteraceae) and Hymeonophyllaceae (Pteridophyte), both of which includes many species endemic to New Zealand.In Celmisia, an ancestral plant, which had estimated to be belong to one group of Olearia, could be migrated from Asustralia, and then diversified in New Zealand. Then, from this group, the ancestors of Celmisia would be derived with following large scale of adaptive radiation. The Australian species of Celmisia, consisting about 10 species, are estimated to be derived from the single ancestor species migrated from New Zealand.On the other hand, in Hymenophyllaceae, some species had been branched at base in their phylogenetic tree, and the others are derived relatively recently.

适应性辐射是物种形成的一种模式，其中一些物种从单一的祖先物种进化而来，并对多样化的环境进行生态适应。这一过程通常在短时间内发生，相对少量的突变可能导致其形态和生态特征的巨大变化。新西兰与邻近的陆地被海洋隔离，因此对于植物来说，很难从其他陆地迁移。新西兰地处高纬度，在冰川时代，大部分土地都被冰川覆盖。因此，新西兰的植物群是研究植物适应辐射的良好模式。我们研究了新西兰紫菀科Celmisia和蕨类Hymeonophyllaceae的物种形成模式，这两种植物都包括许多新西兰特有的物种。在Celmisia中，一种祖先植物，估计属于Olearia的一个组，可以从Asustralia迁移，然后在新西兰多样化。从这一类群出发，经过大规模的适应性辐射，可能衍生出Celmisia的祖先。Celmisia的澳大利亚种约有10种，估计起源于从新西兰迁移过来的单一祖先种;另一方面，在膜蕨科中，一些种在其系统发育树中已经在基部分支，而另一些种则起源较晚。