FOR RELEASE: July 17, 1997
Contact: Blaine P. Friedlander, Jr.Office: (607) 255-3290E-mail: email@example.com
ITHACA, N.Y. -- Elevated levels of carbon dioxide in the atmosphere benefitsome plants by making them more tolerant to cold temperatures, CornellUniversity researchers have discovered.
"This could mean earlier spring planting dates for some crops in thefuture," said David Wolfe, Cornell associate professor in the Department ofFruit and Vegetable Science. "It may also affect the mixture of species innatural plant communities, because only certain plants benefit in thisway." The researchers' study, "Elevated carbon dioxide mitigateschilling-induced water stress and photosynthetic reduction duringchilling," was published recently in the journal Plant, Cell andEnvironment (1997 20, 625-632). Steve Boese, instructor at the College ofCharleston, Charleston, S.C., and Jeff Melkonian, Cornell post-doctoralresearcher, co-authored the paper with Wolfe.
Also, Wolfe will present a poster on this topic at the Plant Biology '97conference cosponsored by the American and Canadian Societies of PlantPhysiology, in Vancouver, Canada, on Aug. 3 and 4.
"Our results are another example of how the increase in carbon dioxide andother greenhouse gases will shake up the plant world," Wolfe said. "Ourmaps of global vegetation zones will inevitably be altered by these sortsof direct effects on plants, whether or not we also have major changes inclimate."
The research was supported by the U.S. Department of Agriculture's SpecialGrants Agricultural Ecosystems Program.
The researchers have focused much of their attention thus far on two crops,beans and cucumbers, that are among a class of plants that tend to wiltwhen temperatures dip below about 45 degrees Fahrenheit. They knew fromprior experiments that elevated carbon dioxide levels often reduce the rateof water loss from leaves, and they suspected this effect would reduce theamount of chilling damage in these species.
This hypothesis was confirmed by their study. Plants grown and chilled atelevated carbon dioxide levels showed less severe wilting and suffered lesspermanent leaf damage than plants grown and chilled at current atmosphericcarbon dioxide concentrations.
"If carbon dioxide in the atmosphere doubles within the next century as weare expecting," Wolfe explained, "these species may be able to withstandtemperatures a few degrees cooler than they do now."
The research is the first to fully document that carbon dioxide can havesuch an easing effect on chilling damage. Most of the work has beenconducted in controlled-environment chambers. The researchers plan tofollow up with field experiments and test other plant species.
Wolfe points out that the rapid rise in atmospheric carbon dioxide is stilla problem from the standpoint of being an important greenhouse gas that maychange our climate in unpredictable ways.
Said Wolfe: "I still think that fossil fuel emissions, the primary culpritin the carbon dioxide rise, are not good for the planet. Many of the othergases that are produced, such as sulfur dioxide, ozone and nitrous oxidescan have direct negative effects on plants and humans, for that matter."
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