Regional differentiation in plant species
Regional differentiation in plant species
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DOI：
10.1086/280955
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发表时间：
1941-01-01
影响因子：
2.9
通讯作者：
Hiesey, WM
中科院分区：
文献类型：
--
作者：
Clausen, J;Keck, WM;Hiesey, WM
物种复合体的遗传-生理分化与其所处的气候带之间存在着相关性。这是由外籍人士建立的。在加利福尼亚州中部从海岸附近延伸到内华达山脉高处的横断面上进行。已采用了几个科的植物，但本文特别讨论了腺委陵菜和小叶委陵菜复合体的区域分化。种属小种。来自相似环境(相同生命区)的不同复合体在移动到新环境时具有相似的修饰和反应模式。物种复合体内的分化纯粹是遗传的，导致了几个主要的气候种族。这可以在染色体数目改变的情况下完成，也可以不改变。植物在特定环境中生存的适合性似乎取决于它们的基因组成，而不是它们的染色体数量。不是物种本身，而是区域气候种族或生态型，是重要的生态环境。当考虑到对环境的适应性时，它是一个单位，它通过作用于种群的自然选择而出现，标志着一个重要的进化步骤。一个物种可以由一个或多个生态型组成，因此占据有限或广泛的栖息地。物种的极限取决于孤立的遗传屏障的形成。一张图表显示了加州中部样带上11个物种复合体的生态和细胞学分化为气候种族。
A correlation exists between the genetic-physiologic differentiation of a species complex and the climatic zones it occupies. This has been established by expts. conducted in a transect across central California extending from near the seacoast to the high Sierra Nevada. Plants of several families have been employed, but the present paper discusses specifically regional differentiation in the Potentilla glandulosa and Achillea millefolium complexes. Races of spp. of distinct complexes from similar environments (the same life zones) have similar modifications and patterns of reaction when moved to new environments. Differentiation within the species complex is purely genetic, resulting in few major climatic races. This may be accomplished with or without a change in chromosome number. Fitness of plants to survive in their given environments appears to lie in their genic composition rather than in their chromosome number. Not the species itself, but the regional climatic race, or ecotype, is the important ecol. unit when fitness to the environment is considered, and its emergence through natural selection acting upon populations marks an important evolutionary step. A species may be composed of one or many ecotypes, and hence occupies a limited or wide range of habitats. The limits of the species depend upon the formation of isolating genetic barriers. A graph illustrates ecological and cytological differentiation of 11 species complexes into climatic races across the central Californian transect.