INDIANAPOLIS (July 20, 2007)—A new study reported in the current issue of Weed Science reveals that rising carbon dioxide (CO2) will drive dandelions to grow taller, stronger and more productive.

Xianzhong Wang, Department of Biology, IUPUI

IUPUI Biology Assistant Professor Xianzhong Wang and graduate student Tamara McPeek investigated how elevated CO2, which is among the "greenhouse gases" associated with global warming, affected reproduction and seed dispersal properties in dandelions. They found that dandelions grown in elevated CO2 (730 parts per million, which is double earth's current CO2 concentration of 370 ppm) produced larger and more robust flowers that are capable of distributing more seeds. As atmospheric CO2 continues to increase, dandelion plants will grow bigger and will become more difficult to control.

The dandelion's occurrence in residential areas is mainly an annoyance to lawn perfectionists, but its presence among agricultural areas can have significantly detrimental effects on crop yields because the dandelion competes with crops for soil nutrients, light and other limited resources.

"In the future, we think humans will have to increase the amount of herbicides and the frequency of their use to kill dandelions," says Wang. He adds that the use of herbicides for controlling weeds contributes to surface and groundwater pollution in the U.S.