Ploidy Level Variability in South American Fescues (Festuca L., Poaceae): Use of Flow Cytometry in Up to 5 1/2-year-Old Caryopses and Herbarium Specimens.
|Year of publication||2006|
|Type||Article in Periodical|
|Magazine / Source||Plant Biology|
|MU Faculty or unit|
|Keywords||Polyploidy; chromosome number; Andes; biogeography; dessicated tissue|
|Description||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 north South America and the high frequence 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 caused by the presence of different cytosolic compounds. About 15% difference in relative DNA content of F. sodiroana and F. vaginalis was proved in simultaneous measurement in seeds.|