Origins, distribution, and local co-occurrence of polyploid cytotypes in Solidago altissima (Asteraceae)
Origins, distribution, and local co-occurrence of polyploid cytotypes in Solidago altissima (Asteraceae)
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DOI：
10.3732/ajb.95.1.50
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发表时间：
2008-01-01
影响因子：
3
通讯作者：
Stireman, John O., III
中科院分区：
文献类型：
--
作者：
Halverson, Kristy;Heard, Stephen B.;Stireman, John O., III
人们越来越认识到，植物种内多倍性对植物多样性的进化以及植物和植物-食草动物群落动态具有重要影响。尽管如此，多倍体细胞型的出现率和它们在当地混合细胞型人群中的命运还不清楚。虽然在许多植物中，特别是在最大的（大陆）空间尺度上，细胞型的局部和区域分布已经得到很好的表征，只有少数几个物种的种群内，特别是非种群细胞型的变化已被记录。此外，很少有研究，如果有的话，在同一植物物种的本地和区域模式有足够的权力来检测细胞型变化的两个尺度。我们评估了共生和频率分布的二倍体，四倍体和六倍体细胞型的一枝黄花（菊科）在当地和区域的空间尺度，采样在美国中西部的假定倍性形式重叠的区域。通过流式细胞仪测定倍性，我们发现许多当地人群含有两种或三种细胞型，即使在相邻人群中，细胞型的相对频率也有很大差异。AFLP标记结果表明，S. altissima可能具有来自不同二倍体谱系的多个起源。我们的研究结果是一致的，最近的观点多倍化作为一个进化的动态现象，频繁的多个起源的高倍性细胞型。
There is growing realization that intraspecific polyploidy in plants has important implications for the evolution of plant diversity and for plant and plant-herbivore community dynamics. Nonetheless, the rate at which polyploid cytotypes arise and their fate in local mixed-cytotype populations are not well understood. Although within- and especially among-population cytotype variation has been documented in many plants, particularly at the largest (continental) spatial scales, local and regional distributions of cytotypes have been well characterized only for a handful of species. Furthermore, few if any studies have addressed both local and regional patterns in the same plant species with sufficient power to detect cytotype variation on both scales. We assessed the cooccurrence and frequency distributions of diploid, tetraploid, and hexaploid cytotypes of Solidago altissima (Asteraceae) at local and regional spatial scales, sampling across a zone of presumed ploidy-form overlap in the midwestern United States. Determining ploidy by flow cytometry, we found many local populations containing two or three cytotypes, with the relative frequencies of cytotypes varying dramatically even among neighboring populations. AFLP marker data suggest that polyploid cytotypes of S. altissima likely have multiple origins from different diploid lineages. Our results are consistent with recent perspectives on polyploidization as an evolutionarily dynamic phenomenon with frequent multiple origins of higher-ploidy cytotypes.