Genome size estimations on Ulmus minor Mill., Ulmus glabra Huds., and Celtis australis L. using flow cytometry

The Ulmaceae family is composed of nearly 2000 species widely distributed in the northern hemisphere. Despite their wide distribution area, there are only four native species in the Iberian Peninsula. In this work the genome size of three of those species (ULMUS MINOR, U. GLABRA, and CELTIS AUSTRALIS) was estimated using flow cytometry. The nuclear DNA content of C. AUSTRALIS was estimated as 2.46 +/- 0.061 pg/2C, of U. MINOR as 4.25 +/- 0.158 pg/2C, and of U. GLABRA as 4.37 +/- 0.103 pg/2C of DNA. No statistically significant differences were detected among individuals of the same species. These species revealed to be problematic for flow cytometric analyses, due to the release of mucilaginous compounds into the nuclear suspension. Despite that, the modified protocol here presented ensured high quality analyses (low coefficient of variation and background debris and nuclear fluorescence stability), opening good perspectives on its application to estimate the genome size of species with similar problems.