January 12, 2007

Results of research appear in Science magazine SIUC scientist part of team that uncovered origins of unique plant known as 'Queen of the Parasites'

by Tim Crosby

stink plant

Caption follows story

CARBONDALE, Ill. -- A plant biology professor at Southern Illinois University Carbondale has co-authored an article that appears in the magazine Science on a unique and very stinky plant.

Daniel L. Nickrent, professor in the Department of Plant Biology in the College of Science, has researched Rafflesia and its place in the plant kingdom for more than two decades, including some 16 years since arriving at SIUC in 1990. The plant is a parasite known for its huge flower — 1 meter or more in diameter and up to 15 pounds — and its horrible smell akin to rotting flesh. Its stench has earned it the nickname "corpse flower."

Nickrent, who has studied parasitic plants from around the world for more than 20 years, including the "Queen of the Parasites," Rafflesia, recently joined up with researchers from Harvard University and the Smithsonian Institution to examine this unusual plant. Charles Davis, a plant biologist at Harvard, is the lead author on a paper that just appeared in Science magazine. Their collaborative work was completed late last fall.

The evolutionary biology research outlined in the article pinpoints the plant's origin. It turns out, much to the surprise of many, the putrid plant shares its lineage with members of the Euphorbiaceae family, which includes poinsettias among others.

The research opened the door to the strange plant's past, and has helped satisfy Nickrent's insatiable curiosity about its origins and evolution.

"These are really bizarre plants where the vegetative body — leaves, stems and such — are reduced to nothing," he said. "We didn't know where Rafflesia fit, in evolutionary terms, among other flowering plants. The study of its biology has been very difficult."

The plant grows deep in the jungles of Southeast Asia. As a parasite, Rafflesia lives as a fungus-like strand inside a particular host vine plant for years before eventually developing a bud on the exterior of the host. That bud grows and opens into the characteristically huge flower.

Along with its putrid smell the plant can also create heat. Some researchers speculate the plant uses these traits to attract carrion flies to land and pollinate it.

Its relationship to other flowering plants had vexed scientists for the better part of two centuries. In 2004, scientists, including Nickrent, used molecular methods (DNA sequencing) to narrow down the plant's heritage to the correct order. That order, however, includes thousands of species. The new research identifies the specific group most closely related to Rafflesia.

Nickrent said being published in the renowned magazine Science was a thrill.

"It's splashy. It's one of the top two journals in the sciences and it gets you a lot of airplay," he said. "In terms of recognition, there's no parallel. They're very selective."

Aside from the basic scientific knowledge the team gained, achieving a better understanding of the genetic mechanisms underlying floral gigantism could lead to advances in more applied sciences such as agriculture and horticulture, where there is much interest in growing bigger flowers, Nickrent said.

(Caption: Amazing size, smell – A woman examines the Rafflesia arnoldii plant in Sumatra, Indonesia, in July 2005. Southern Illinois University Carbondale plant biology Professor Daniel L. Nickrent has co-authored an article appearing this month in the magazine Science that outlines research pinpointing the unique parasitic plant's origins.)

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