The genome size of an organism is determined by its capacity to tolerate genome expansion. Veselý et al. study 47 pairs of geophytic taxa and their closest non-geophytic relatives across the whole angiosperms. They find increased genome sizes in geophytes compared to their non-geophytic relatives, regardless of the storage organ type and regardless of whether or not vernal geophytes, polyploids or annuals are included in the analyses. The tendency of geophytes to possess higher genome size suggests the presence of a universal mechanism allowing for genome expansion. It is assumed that this is primarily due to the nutrient and energetic independence of geophytes perhaps allowing continuous synthesis of DNA, which is known to proceed in extreme cases of vernal geophytes even in dormant stages.
Nutrient reserves in geophytes may allow genome size increase
A study of 47 pairs of geophytic taxa and their closest non-geophytic relatives across the whole angiosperms.