New Phytol. http://doi.org/3v7 (2015)

Genome size can serve as an indicator of species invasiveness in relatively high light environments, where weeds often have smaller genomes than native plants. An analysis of the genome size of native and invasive forest shrubs suggests that genome size can also serve as an indicator of invasiveness under more light-limited conditions.

Jason Fridley and Alaä Craddock, of Syracuse University, examined the physiology, growth characteristics and genome size of 54 species of woody shrubs and vines that grow in the deciduous forests of the eastern US. Both native and invasive plants were included in the analysis. Invasive species had smaller genomes and higher photosynthetic capacities, and exhibited more rapid summer growth, than native species. Species with smaller genomes also exhibited delayed budbreak during spring, but this trait was unrelated to invasiveness.

The researchers suggest that the small size of invasive plant genomes permits more rapid rates of cell division, and thus increased growth — relative to native plants — as temperatures rise during the growing season, putting these plants at a competitive advantage.