Biologists have identified plant enzymes that may help to engineer plants that take advantage of elevated carbon dioxide to use water more efficiently. The finding could help to engineer crops that take advantage of rising greenhouse gases.
Plants take in the carbon dioxide they need for photosynthesis through microscopic breathing pores in the surface of leaves. But for each molecule of the gas gained, they lose hundreds of water molecules through these same openings. The pores can tighten to save water when CO2 is abundant, but scientists didn't know how that worked until now.
A team led by Julian Schroeder, professor of biology at the University of California, San Diego, has identified the protein sensors that control the response. Enzymes that react with CO2 cause cells surrounding the opening of the pores to close down they report in the journal Nature Cell Biology online December 13.
The discovery could help to boost the response in plants that do not take full advantage of elevated levels of the gas, Schroeder says. "A lot of plants have a very weak response to CO2. So even though atmospheric CO2 is much higher than it was before the industrial age and is continuing to increase, there are plants that are not capitalizing on that. They're not narrowing their pores, which would allow them to take in CO2, while losing less water," he said. "It could be that with these enzymes, you can improve how efficiently plants use water, while taking in CO2 for photosynthesis. Our data in the lab suggest that the CO2 response can be cranked up."
Plants lose 95 percent of the water they take in to evaporation through these pores, also called stoma. Modifying crops to be more responsive to CO2 could help farmers meet demand for food as competition for water increases. In California, for example, 79 percent of water diverted from streams an
|Contact: Julian Schroeder|
University of California - San Diego