Instituto de Botánica del Nordeste (UNNE, CONICET), Casilla de Correo 209, 3400 Corrientes, Argentina.
J Plant Res. 2011 Jan;124(1):25-34. doi: 10.1007/s10265-010-0347-0. Epub 2010 May 1.
Cytogeographical variability among 564 plants from 26 populations of Turnera sidoides subsp. pinnatifida in mountain ranges of central Argentina was analysed with meiotic chromosome counts and flow cytometry and is described at regional and local scales. Populations were primarily tetraploids (2n = 4x = 28), although diploid (2n = 2x = 14), hexaploid (2n = 2x = 42), and mixed populations of diploids and triploids (2n = 3x = 21) were also found. Diploids, triploids, and hexaploids were fewer in number and restricted to narrow areas, while tetraploids were the most common and geographically widespread cytotype. Diploids grew at higher altitudes and in colder and wet locations; tetraploids had the broadest ecological spectrum, while hexaploids occurred at the lowest altitudes and in drier conditions. The cytotypes were also spatially segregated at a microgeographical scale. Diploids grew in the piedmont, tetraploids were in the adjacent valley, and in the contact zone of both cytotypes, patches of diploids and triploids were found. At a regional scale, the distribution of the cytotypes may be governed by a combination of ecological and historical variables, while segregation in the contact zone may be independent of the selective environment because the cytotypes are unable to coexist as a result of reproductive exclusion. The role of triploids is also discussed.
对来自阿根廷中部山脉 26 个种群的 564 种植物进行了细胞地理学变异分析，包括减数分裂染色体计数和流式细胞术分析，并在区域和局部尺度上进行了描述。种群主要为四倍体（2n = 4x = 28），但也存在二倍体（2n = 2x = 14）、六倍体（2n = 2x = 42）和二倍体和三倍体的混合种群（2n = 3x = 21）。二倍体、三倍体和六倍体数量较少且局限于狭窄区域，而四倍体是最常见和地理分布最广的细胞型。二倍体生长在较高海拔和较冷、较潮湿的地方；四倍体具有最广泛的生态谱，而六倍体则出现在较低海拔和较干燥的条件下。细胞型也在微观地理尺度上发生了空间分离。二倍体生长在山麓，四倍体在相邻的山谷中，而在两个细胞型的接触区，发现了二倍体和三倍体的斑块。在区域尺度上，细胞型的分布可能受到生态和历史变量的共同作用，而在接触区的分离可能与选择环境无关，因为由于生殖排斥，细胞型无法共存。还讨论了三倍体的作用。
