Climate Change May Accelerate the Spread of Invasive Plants

Plants produce and release different compounds that could be phytotoxic and can prevent the growth of other plants close to them. This process, known as allelopathy, is used by certain species to minimize competition for precious resources like nutrients and water with nearby plants. The common reed (Phragmites australis) produces the phytotoxic gallic acid to keep away other plants. Researchers from the University of Delaware, however, found that allelopathic inhibition can be more complex than previously thought.

Thimmaraju Rudrappa and colleagues discovered that Phragmites, an established invasive species in the U.S., delivers a one-two chemical knock-out punch to snuff out its victims. The toxin produced by the plant is degraded by sunlight, particularly ultraviolet rays (UVB), and causes severe deleterious effects on other native plants.

"Our research addresses the growing questions of increased UV-B incidences because of global warming and its ultimate effect on plants. In this case, an invasive plant is accidentally utilizing the changed global conditions for its survival and invasion," said Harsh Bais co-author of the study. UVB converts the gallic acid produced by Phragmites to mesoxalic acid, a potent compound that destroys structural protein in the roots within minutes of exposure.

Read the complete article at http://www.udel.edu/udaily/2009/jun/superweed060309.html The paper published by Plant Signaling & Behavior is available to subscribers at http://www.landesbioscience.com/journals/psb/article/8698