Nuclear DNA C-values in 12 species in nymphaeales

摘要

Nuclear DNA C-values are the basic data of species and used in a strikingly wide range of biological fields. Genome size of the most species belonging to the three families Nulembonaceae, Cabombaceae and Nymphaeaceae in Nymphaeales were not assessed, especially none of the species in Cabombaccae was reported so far. In present research, flow cytometry was used to assess the genome size of 12 species belonging to the three families in Nymphaeales and a standard squash technique to count the chromosome numbers of the tested materials. In the tested different species, 2C nuclear DNA contents ranged from 1.55 to 8.11 pg, which is more than fivefold variation. And chromosome numbers varied from 2n=16 to 2n=72. Differences between the species or among populations within a species were also recorded by statistical analysis. The tested species are all small genomes except two species of Victoria. The ploidies did not matched with their DNA contents very well in Nympbaea. Significant differences were found between the species of Nymphaea, between those of Victoria and among wild populations of Nelumbo nicifera; while no obvious differences were found between the species of Nelumbo and among the cultivars of Euryale ferox as well as among those of Brasenia schreberi, respectively.