Venus Flytrap Still Mystifies, Inspires

The Venus flytrap remains one of the most intriguing plants in the world.  What makes it snap shut in a tenth of a second?  Can we imitate its motion without muscles, wires or batteries?

A press release from the American Physical Society’s Division of Fluid Dynamics sets up the questions:

Plants lack muscles, yet in only a tenth of a second, the meat-eating Venus fly trap hydrodynamically snaps its leaves shut to trap an insect meal. This astonishingly rapid display of botanical movement has long fascinated biologists. Commercially, understanding the mechanism of the Venus fly trap’s leaf snapping may one day help improve products such as release-on-command coatings and adhesives, electronic circuits, optical lenses, and drug delivery.

Both Science Daily and Live Science reported on research by a French team that seeks to understand how botanical tissues can respond so quickly.  One theory has been ruled out – that water travels from the inside cells to outside cells.  By measuring the fluid pressure of the cells (a tricky experiment), Mathieu Colombani’s team found that movement of water is too slow to account for the traps’ fast action.  They were scheduled to present their findings at an APU meeting in San Diego on Nov. 18.

Live Science quoted Charles Darwin calling the Venus flytrap “one of the most wonderful plants in the world.” It grows in coastal bogs in North Carolina where soil nutrients are scarce – thus insects provide some of its nitrogen.  Still, “despite the plant’s notoriety, its closing mechanism remains a mystery 250 years after its discovery.”  Colombani’s team is the first to examine the mechanism at the cellular level.  “The researchers are currently testing another popular explanation that says the elasticity of the plant’s cell walls changes, causing the leaves to destabilize and snap together,” Live Science said.  “Colombani says that whatever the mechanisms behind the remarkable plant’s bite are, they could have potential applications in medicine or other fields.”

Teachable Moment: Parents, kids are fascinated by the Venus flytrap.  You can often buy the little plants in local nurseries.  Build a little Venus flytrap terrarium at home for the family, and teach the kids how to feed and care for the plants like they would a pet.  Much as they want to snap the traps over and over, they will quickly learn that the delicate plants need care and gentle handling.  Tell them that here is something easily observed and tested right under a scientist’s nose, yet science cannot explain it after 250 years of trying.  Focus on the beautiful design of these traps, how elegant and effective they are.  Add that an explanation might lead to cool toys and products that operate without batteries.  Kids need to know that there are still fascinating questions in science they might be able to solve, and that solving this puzzle might make the world a better place.  Show them, though, that science needs to explain via experimental proof, not speculation.  As it was for Faraday, Joule and other great creationary scientists who started young when they became intrigued by the wonders of nature, science is for everyone.