In this research, the scientists found that the gallic acid released by Phragmites is degraded by ultraviolet light to produce another toxin, mesoxalic acid, effectively hitting susceptible plants and seedlings with a double-whammy.
The mesoxalic acid triggers a similar "cellular death cascade" in victim plants as gallic acid does, Bais said, destroying the tubulin and actin, the structural protein in the roots, within minutes of exposure.
The scientific team detected the biological concentrations of mesoxalic acid in Delaware wetlands, in stands of both exotic and native Phragmites australis. The study highlights the persistence of the photo-degraded phytotoxin, particularly potent in the exotic species of the plant, and its enhanced effects against the native species of Phragmites, which is becoming increasingly endangered in the United States.
Walnut trees, pine trees, ferns and sunflowers are among the plants that release harmful chemicals to prevent other plants from growing too close to them.
However, Phragmites uses this strategy not so much to keep other plants away, but to aggressively conquer them and invade new territory, Bais said.
|Contact: Tracey Bryant|
University of Delaware