Project Title: An Unexplored mechanism of plant invasion: Spread by stem fragments
Mentor: Laura Meyerson
Phragmites Australis is a wetland grass that is present in North America in three genetically distinct lineages: Gulf Coast, introduced, and native. Recent studies have shown that the populations from the introduced lineages have become increasingly invasive in our wetlands throughout the United States. One reason for this rapid expansion is thought to be because of the plant’s ability to reproduce both sexually and asexually. In this study, we compared a relatively unexplored method of reproduction in which Phragmites australis reproduces and creates new plants out of fragments of fallen stems. We tested if the three lineages of Phragmites differed in the success of reproduction through stem fragments by cutting stems from potted populations (9-10 from each lineage), placing them in water, and monitoring the new growth that emerged. We hypothesized that the introduced populations would be the most successful because their increasing invasiveness. At the end of our five-week trial, we found that the Gulf Coast populations were the most successful at propagating new growth from stem fragments. These populations not only grew the most (height) but also had a higher proportion of stem nodes with new growth. There was no statistically significant difference between the growth of native or introduced populations.