USM Prof to Talk on Off-setting Fertilizer Damage

USM Professor of Biology Thomas J. Knight is working on engineering greater plant productivity through genetic manipulation of plants. Knight’s research will eventually yield plant cultivars that require less nitrogen fertilizer to yield the same productivity. This is vital for farmers who must meet mandates to cut the application of nitrogen fertilizer to protect coastal waters.

In addition, Knight’s research indicates possible ways to offset the greenhouse effect that causes global warming.

Knight will present some of his research findings in a talk at 3 p.m., Monday, December 4 in the Woodbury Campus Center on USM’s Portland campus.

Nitrogen run-off traveling down the Mississippi River has created a dead zone in the Gulf of Mexico that in some recent summers has included an area the size of New Jersey. Dead zones of smaller size are appearing in other coastal waters, and oxygen-depleted ocean regions have caused fishermen in many coastal areas to worry about a collapse of the fisheries. A 1998 article in the New York Times described the problem: “The trouble with the dead zone is that it lacks oxygen, scientists say, apparently because of pollution in the form of excess nutrients flowing into the gulf from the Mississippi River. Animals in this smothering layer of water near the bottom of the sea must flee or perish.” The NY Times article also says that “a U.S. Geological Survey study estimated that more than half of the nitrogen reaching the gulf appears to come from agricultural sources.”

Over the past five years, Knight, who holds a Ph.D. in plant physiology from Rutgers University, has studied the regulatory mechanisms of plant carbon-nitrogen interactions. Some of this work was supported by a $125,000 National Science Foundation grant for a study on transferring nitrogen metabolism from the roots to the leaves of oat plants, thereby increasing plant productivity.

Knight's research indicates that by genetically manipulating the root and leaf tissue, plants can be enabled to grow larger and with more nutrients using less nitrogen. This research suggests future applications to address food shortages in the Third World. The method could be applied to trees, too, he predicts, to speed up growth so that a tree could be harvested in two thirds the time.

The U.S. Department of Energy has been following Knight's research on nitrogen-carbon metabolism because it may offer a way to lower build up of atmospheric carbon dioxide, which is believed to cause global warming. Knight believes it may be possible to prompt plants, by manipulating their nitrogen-carbon balance, to store excess atmospheric carbon dioxide in their leaves. By fixing carbon dioxide in plants, the amount of this gas that is held in the atmosphere, blocking heat radiation, can be reduced.