Smarda P, Stancík D
Department of Botany, Faculty of Science, Masaryk University in Brno, Kotlárská 2, CZ-611 37 Brno, Czech Republic.
Plant Biol (Stuttg). 2006 Jan;8(1):73-80. doi: 10.1055/s-2005-872821.
Ploidy levels and chromosome numbers for 24 species of Festuca L. from 29 sites in Bolivia, Colombia, Ecuador and Venezuela are given. The ploidy level of 22 species is reported for the first time. A higher proportion of tetraploids in northern South America and the high frequency of polyploids in the whole continent are documented. In combination with chromosome counts, ploidy level was determined using flow cytometry in 4- to 5 1/2 -year-old herbarium specimens and mature caryopses. Flow cytometric determination from seeds was more reliable than determination from herbarium specimens. In herbarium specimens, the youngest, fresh green leaves, still hidden in sheaths, seem to be most suitable for cytometric determination. In old, brownish leaves, or poorly preserved herbarium specimens, the degradation of DNA signal in flow histograms was documented. DNA content measured in seeds was always higher than that measured in herbarium specimens, which may be caused by the presence of different cytosolic compounds. Differences of about 15% in relative DNA content of F. sodiroana and F. vaginalis was found in simultaneous measurements in seeds.
给出了来自玻利维亚、哥伦比亚、厄瓜多尔和委内瑞拉29个地点的24种草属植物的倍性水平和染色体数目。22个物种的倍性水平首次被报道。记录了南美洲北部四倍体的较高比例以及整个大陆多倍体的高频率。结合染色体计数，在4至5.5年生的标本馆标本和成熟颖果中使用流式细胞术确定倍性水平。从种子进行流式细胞术测定比从标本馆标本进行测定更可靠。在标本馆标本中，最年轻的、仍隐藏在叶鞘中的鲜绿色叶子似乎最适合进行细胞计数测定。在老的、褐色的叶子或保存不佳的标本馆标本中，记录到了流式细胞直方图中DNA信号的降解。种子中测得的DNA含量总是高于标本馆标本中测得的，这可能是由不同胞质化合物的存在导致的。在种子的同步测量中发现，索迪罗草和阴道草的相对DNA含量相差约15%。
