Ringing an airport security gate, such planted sensors could ensure foolproof security by turning white the moment they detect a terrorist with bombs approach the premises, a report in Daily Mail said.
It works because the receptor proteins in plant DNA respond naturally to threatening stimuli by releasing chemicals called terpenoids to thicken the leaf cuticle, thereby changing its colour.
This defensive reaction formed the basis for research into detecting explosives carried out by University of Colorado biologist and Professor June Medford and the Pentagon, the report said.
"Plants can’t run or hide from threats," Medford said, "so they’ve developed sophisticated systems to detect and respond to their environment."
The researchers designed a computer programme to manipulate a plant's natural defence mechanism by teaching its receptors to respond in the same way to chemicals found in explosives and in air and water pollutants, according to a Colorado statement.
These computer-redesigned receptors were modified to function in plants, and targeted to the plant cell wall where they can recognise pollutants or explosives in the air or soil nearby.
The plant detects the substance and activates an internal signal that causes it to lose its green colour, turning its leaves white.
Medford said: "We’ve 'taught' plants how to detect things we’re interested in and respond in a way anyone can see, to tell us there is something nasty around."