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Venus flytraps kill with chemicals like those from lightning bolts

PORTLAND, OREGON—Venus flytraps have a well-known way of dispatching their victims: They snare inquisitive insects that brush up against trigger hairs in their fly-trapping pods (above). But now, physicists have discovered that the triggering process may involve the release of a cascade of exotic chemicals similar to the whiff of ozone that tingles your nose after a lightning bolt.

To study this process, scientists used an electrical generator to ionize air into a “cold plasma,” which they then gently blew toward a flytrap in their lab.

Normally, the flytrap’s closure is caused by an electrical signal created when two or more trigger hairs are brushed. But highly reactive chemicals in the plasma stream such as hydrogen peroxide, nitric oxide, and ozone had the same effect, even when they were blown at the pods too gently to trigger them by motion, they reported here last week at the annual Gaseous Electronics Conference.

It’s a useful finding because the types of reactive oxygen and nitrogen molecules in cold plasmas play a major role in biological processes, including cell signaling. But normally, such processes have to be studied through complex analyses of cell cultures. With the Venus flytrap, they can be observed directly, when the pods snap shut.

Understanding such processes, the scientists say, could help biomedical researchers and aerospace engineers create a new generation of “intelligent materials” that can use similar signaling processes to change shape as needed, much as the Venus flytrap reflexively snaps shut when it senses its prey. It’s an open and shut case for new research, including a more detailed examination of exactly how the various parts of the plant know how to spring shut at just the right moment.