中欧早熟禾属类群间的核DNA含量变异
Nuclear DNA content variation among Central European Koeleria taxa.
作者信息
Pecinka Ales, Suchánková Pavla, Lysak Martin A, Trávnícek Bohumil, Dolezel Jaroslav
机构信息
Institute for Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, Gatersleben, D-06466, Germany.
出版信息
Ann Bot. 2006 Jul;98(1):117-22. doi: 10.1093/aob/mcl077. Epub 2006 May 12.
BACKGROUND AND AIMS
Polyploidization plays an important role in the evolution of many plant genera, including Koeleria. The knowledge of ploidy, chromosome number and genome size may enable correct taxonomic treatment when other features are insufficient as in Koeleria. Therefore, these characteristics and their variability were determined for populations of six central European Koeleria taxa.
METHODS
Chromosome number analysis was performed by squashing root meristems, and ploidy and 2C nuclear DNA content were estimated by flow cytometry.
KEY RESULTS
Three diploids (K. glauca, K. macrantha var. macrantha and var. pseudoglauca), one tetraploid (K. macrantha var. majoriflora), one decaploid (K. pyramidata) and one dodecaploid (K. tristis) were found. The 2C nuclear DNA content of the diploids ranged from 4.85 to 5.20 pg. The 2C DNA contents of tetraploid, decaploid and dodecaploid taxa were 9.31 pg, 22.89 pg and 29.23 pg, respectively. The DNA content of polyploids within the K. macrantha aggregate (i.e. within K. macrantha and K. pyramidata) was smaller than the expected multiple of the diploid genome (K. macrantha var. macrantha). Geography-correlated variation of DNA content was found for some taxa. Czech populations of K. macrantha var. majoriflora had a 5.06% smaller genome than the Slovak ones. An isolated eastern Slovakian population of K. tristis revealed 8.04% less DNA than populations from central Slovakia. In central and north-west Bohemia, diploid and tetraploid cytotypes of K. macrantha were sympatric; east from this region diploid populations, and towards the west tetraploid populations were dominant.
CONCLUSIONS
Remarkable intra-specific inter-population differences in nuclear DNA content were found between Bohemian and Pannonian populations of Koeleria macrantha var. majoriflora and between geographically isolated central and eastern Slovakian populations of K. tristis. These differences occur over a relatively small geographical scale.
背景与目的
多倍体化在包括赖草属在内的许多植物属的进化中起着重要作用。当其他特征（如在赖草属中）不足时，倍性、染色体数目和基因组大小的知识可能有助于进行正确的分类处理。因此，对六个中欧赖草属分类群的种群进行了这些特征及其变异性的测定。
方法
通过压片法对根分生组织进行染色体数目分析，并通过流式细胞术估计倍性和2C核DNA含量。
主要结果
发现了三个二倍体（蓝灰赖草、大花赖草变种大花赖草和假蓝灰赖草变种）、一个四倍体（大花赖草变种大花多花型）、一个十倍体（圆锥赖草）和一个十二倍体（三毛赖草）。二倍体的2C核DNA含量在4.85至5.20皮克之间。四倍体、十倍体和十二倍体分类群的2C DNA含量分别为9.31皮克、22.89皮克和29.23皮克。大花赖草复合体（即大花赖草和圆锥赖草内）内多倍体的DNA含量小于二倍体基因组预期的倍数（大花赖草变种大花赖草）。发现一些分类群的DNA含量存在与地理相关的变异。大花赖草变种大花多花型的捷克种群基因组比斯洛伐克种群小5.06%。斯洛伐克东部一个孤立的三毛赖草种群的DNA比斯洛伐克中部种群少8.04%。在波希米亚中部和西北部，大花赖草的二倍体和四倍体细胞型同域分布；在该地区以东二倍体种群占优势，而向西四倍体种群占优势。
结论
在大花赖草变种大花多花型的波希米亚和潘诺尼亚种群之间以及地理上孤立的斯洛伐克中部和东部三毛赖草种群之间，发现了显著的种内核DNA含量种群间差异。这些差异发生在相对较小的地理尺度上。
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