By changing color, plants can signal presence of explosives.

• Position: Defense Technology Newswire

Authorities have used plants to catch the bad guys for ages, but it has never been quite this literal.

Researchers at Colorado State University are using actual plants--green, leafy organisms--to detect explosives and environmental pollutants.

"We envision these plants enabling ordinary people to know if their air and water are clean, as well as helping to provide security around airports, shopping centers and sports arenas," said professor, plant biologist and lead researcher June Med-ford. They could be placed around a home, too, so a family could tell if it had radon in the basement just by looking at a plant, she added.

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Research partners at Duke University and the University of Washington used a computer program to redesign naturally occurring proteins called receptors. Med-ford and her team then modified these receptors to work in the cell walls of plants, which will turn from green to white when they detect certain chemicals in the air or soil. The plants will change back to their normal green when the dangerous substance is removed from the environment.

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"The idea to make detector plants comes directly from nature," Medford said. "Plants can't run or hide from threats, so they've developed sophisticated systems to detect and respond to their environment. We've 'taught' plants how to detect things we're interested in...