Our lab had the opportunity to contribute to a new paper in the Journal of Chemical Ecology that shows the release of toxic gallic acid by the common reed Phragmites australis is not the key to its successful invasion of freshwater and brackish habitats in North America. A series of previous publications suggested that release of gallic acid might explain the reed’s ability to produce large stands and exclude native plants. However, work by our collaborators in the Ashland University Department of Chemistry with four Phragmites populations from Ohio and North Carolina found only trace amounts of gallic acid in the plant and none in surrounding soils.
Josh Allman, a junior conducting research in my lab, performed an analysis of a genomic region that differs between North American native Phragmites populations and the invasive strain. Josh’s restriction length polymorphism analysis showed that all four populations in our study were invasive and, according to past work, should contain gallic acid. The lack of gallic acid in these populations suggests that at a minimum gallic acid release is not a general explanation for the invasive success of Phragmites.
Students in my spring 2012 marine biology course took part in the collection of samples from North Carolina during a 4-day field trip to the Outer Banks. Another student in my lab, Kelly Sullivan, is following up on this work by developing methods to study whether chemicals produced by Phragmites repel the snail herbivores in their habitat. Hopefully I can report back on that work soon.