Video 1: A mature bunchberry flower (Cornus canadensis) explodes. Images taken at 10,000fps (1 frame = 0.1 millisecond).		Video 2: A distant view of the floral explosion, overexposed to highlight the movement of the pollen. Filmed at 1,000 fps.

When Assistant Professor of Biology Marta Laskowski first saw the bunchberry dogwood "explode," she wanted to figure out how the tiny white flower could open so quickly. Now, with the publication of the article "A record-breaking pollen catapult" in the current issue of Nature, readers can enjoy Laskowski's visually stunning research and learn more about the fastest plant movement recorded by scientists to date.

"The bunchberry flower can open in under 0.4 milliseconds--which is several hundred times speedier than the snap of a Venus fly trap." says Laskowski. "This plant is tremendously exciting and just goes to show how much we have left to discover in the natural world."  

Joan Edwards, a field biologist at Williams College, and her undergraduate student Sarah Klionsky recently rediscovered the rapid opening of bunchberry dogwood flowers. Curious to understand how the "explosion" occurred, she called on Laskowski, a plant biologist, as well as Dwight Whitaker, a physicist.

As the flowers burst open, the petals quickly separate and flip back, exposing the stamens. During the first 0.3 milliseconds, the stamens accelerate at up to 24,000 m/s ², approximately 800 times the force astronauts experience during take-off. A specialized catapult design that resembles a medieval trebuchet allows the stamens to shoot their pollen 2.5 centimeters into the air, 10 times the height of the flower. The pollen then becomes embedded on the bodies of insects that transfer it to other flowers or is carried away by the wind.

The article's publication in Nature has generated national, as well as international, media interest, with publications such as the New York Times, the Los Angeles Times, the Baltimore Sun, Science.com, London's Daily Telegraph, and Germany's Spektrum running articles about the exploding flowers. National Public Radio, the BBC, the Discovery Channel, and Canal Plus are also planning to run segments about the bunchberry dogwood.

"Having an article published in Nature has been a fantastic experience," Laskowski says. "This project demonstrates what a wonderful place Oberlin is for doing science, and how many opportunities there are for students to be a part of that."

"A record-breaking pollen catapult" (Nature magazine, May 12, 2005)

Cornus canadensis (bunchberry or Canadian dogwood) and its closely related Cornus suecica (Swedish cornel) grow in the tiaga or boreal forests of the northern hemisphere.

Flowering shoots of Cornus canadensis have a single inflorescence of 20-50 flowers, which are subtended by four showy white bracts.

Each flower has four valvate petals, which are fused at the tip. The petals restrain the four stamens that store elastic energy used to launch pollen.

Marta Laskowski, Assistant Professor of Biology Biology Department web site