Genome size of Adriatic seagrasses

Genome size (C-value) was measured in four species of Adriatic seagrasses with interphase-peak DNA image cytometry. The estimated 2C-value was 1.5 pg DNA for Zostera noltii (2 n=12), 1.2 pg for Zostera marina (2 n=12), 1.1 pg for Cymodocea nodosa (2 n=28) and 6.2 pg for Posidonia oceanica, using Pisum sativum (2C-value=8.84 pg) as the calibration standard. Seagrass leaves were fixed in 4% buffered formaldehyde to mitigate stoichiometric error due to tannins and post-fixed in 3:1 methanol:acetic acid (MAA). DNA was stained with the Feulgen reaction after hydrolysis in 5 M HCl for 90 min at 20 °C. Comparison of genome size of seagrasses with the data for other species of Alismatidae indicated that the ancestral genome of Alismatidae was relatively small.