Killer Plant Sucks in Prey at Record Speed

Plants would seem to live in the slow lane, but a carnivorous aquatic plant may be an exception.

- Bladderworts have just been named the world's fastest trapping carnivorous plants.

- These aquatic meat-eaters suck and trap prey in less than a millisecond.

- The sucking and trapping mechanism is among the fastest movements in the entire plant kingdom.

Aquatic, meat-eating bladderworts are among the world's best suckers and they have just been named the fastest trapping carnivorous plants, according to a Proceedings of the Royal Society B study.

Their traps suck in prey in less than a millisecond, making this one of the speediest movements in the entire plant kingdom.

"The popular Dionea (Venus fly trap) is one hundred times slower," co-author Philippe Marmottant told Discovery News.

Marmottant, a researcher in the Interdisciplinary Physics Laboratory at Grenoble University, and his colleagues used high-speed video cameras and powerful microscopes to capture the trapping action of three species of bladderworts in the genus Utricularia.

Click here to see these hungry plants in action.

The investigations showed that glands in each plant first pump water out of a closed trap.

"This deflates the trap and stores elastic energy, like the stored energy in a bent bow, and also generates a depression inside, like with a rubber pipette," Marmottant explained.

During the second actual trapping phase, the stored elastic energy is released.

"The firing starts when sensitive trigger hairs located on the (trap) door are touched," he said. "We showed that, because of the inside depression, the door is already on the verge of inverting towards the interior. The curvature inversion of the door is an abrupt event known as an 'elastic buckling' phenomenon, and happens in everyday life when a curved elastic wall is set under depression, like a balloon or plastic bottle."

"Because of the curvature inversion, the door opens and liquid rushes in to inflate again the trap," he added.

As liquid rushes in, the plant sucks in the prey, such as a small crustacean, that triggered the trap door's opening. The force is so powerful that swirls develop inside the trap, further preventing prey from escaping after the trap door quickly shuts. Digestive juices released by glands then dissolve the trapped individual.

Sometimes "larger" animals, such as tadpoles or worms, wind up half in and half out of the trap, gruesomely losing part of their body to the plant's hunger.

When the trap door shuts, the plant excretes mucilage next to a special cuticle around the door, creating a watertight seal. The same trap can fire hundreds of times, all following the very precise and repeated mechanism.

Only four or so other movements are faster in the plant kingdom, and these are all of an explosive nature and not repeatable. Such speedy happenings, according to Marmottant, include the explosive flower opening of Cornus canadensis, the exploding fruit of Impatiens, the forcible pollen sac attachment in Catasetum fimbriatum, and the squirting cucumber action of Ecballium elaterium.

Yoel Forterre, a Marseille University researcher who is an expert on the biomechanics of plants, told Discovery News that the latest findings about Utricularia are "great and impressive."

"By combining precise high-speed visualization and physical modeling, the authors for the first time provide a comprehensive description of the mechanics of a bladderwort's trap," Forterre said, adding that he hopes future research will shed more light on what happens at the molecular level when the plant's traps open and shut.

Marmottant and his colleagues point out that such research could one day improve common microfluidic gadgets, such as the heads of inkjet printers and lab-on-a-chip devices that process biological samples, like blood and human DNA.

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