Higher carbon dioxide levels could promote the
growth of purple and yellow nutsedge--quick-growing invasive weeds that plague
farmers and gardeners in many states. Photo courtesy of Jeff Stachler, Ohio
State University, Bugwood.org
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Elevated Carbon Dioxide Boosts Invasive Nutsedge
By Laura
McGinnis
June 9, 2008 Elevated levels of carbon dioxide (CO2)
could promote the growth of purple and yellow nutsedgequick-growing
invasive weeds that plague farmers and gardeners in many states.
That's the conclusion of plant physiologist
Hugo
Rogers and his colleagues at the Agricultural Research Service (ARS) National Soil Dynamics Laboratory (NSDL)
in Auburn, Ala.
With ARS and Auburn University
colleagues, Rogers grew purple nutsedge (Cyperus rotundus L.) and yellow
nutsedge (C. esculentus L.) in chambers designed to mimic the
atmospheric CO2 levels predicted to occur within the next centuryabout
twice existing levels.
They found that both species benefited from elevated CO2, particularly
purple nutsedge.
Although neither species is native to the United States, purple and yellow
nutsedge can be found all over the country. Purple nutsedge can tolerate
extremely high temperatures and is a major problem in the southern United
States, whereas yellow nutsedge is better suited to more temperate climates.
Both species displace native plants and reduce yields in a variety of
important agricultural crops, including corn, cotton and rice. Purple and
yellow nutsedge spread via rhizomes and underground tubers, and are extremely
difficult to control.
The Auburn scientists observed that both species grew larger in the elevated
CO2 chambers than in control chambers. The plants had more tubers and greater
water use efficiency, indicating that they could become increasingly
competitive in an elevated-CO2 environment. This could result in reduced crop
yields and displaced native flora.
This research, published recently in the Journal of Environmental Quality, is
the first in a series of papers on the effects of CO2 on invasive weeds.
ARS is a scientific research agency of the U.S. Department of Agriculture.