March 27, 2012

‘Wee Stinky’: The (Not So) Sweet Smell of Success

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Thousands of onlookers shuffled into the Kenneth Post Greenhouse over spring break to catch a rare glimpse — and whiff — of the University’s first-ever blooming “corpse flower.”

This rare Sumatran plant, known scientifically as Amorphophallus titanum,and popularly as the “titan arum,” is native to the slopes of the Barisan mountain range in western Indonesia and blooms typically only once every seven to 10 years, though sometimes as seldom as once every few decades.

Nicknamed “Wee Stinky” by popular vote (after Wee Stinky Glen, the small stream that flows behind the Cornell Store), the titan arum began flowering Sunday afternoon, March 18. The blooming lasted fewer than 48 hours, drawing roughly 3,500 spectators the second day. After four days the plant collapsed and is no longer advertised to the public. The event and its lead-up attracted some 10,000 people between March 14-19.

Prof. Robert Raguso, neurobiology and behavior, commented, “If you get behind the statue of David and look at all the people–it’s like going to the Mona Lisa, it commands this attention, it has ‘star power.’ There are famous photographs of young actresses and actors that have this kind of effect on a crowd. This plant had that effect — it had ‘star power.’”

During blooming, the titan arum stinks like a decaying body. “It smells like rotting flesh,” said Prof. Karl Niklas, plant biology, “but there’s this sickeningly sweet undertone to it and it’s just nasty — it’s just plain nasty.” Though repulsive to most humans, the rank scent allures Sumatran carrion beetles and flesh flies, which help to pollinate the plant.

The Towering Stalk

Despite what its name suggests, the “corpse flower” is not actually a flower but a collection of flowers — a natural bouquet bearing about 450 female flowers encircling the base of its column-like central spike, called the spadix, with about 500 to 1,000 smaller grayish male flowers above those.

“Even some of the more national media were making this mistake,” Niklas said; like the calla lily, which is a cluster of flowers, “it is actually an inflorescence,” he said.

The titan arum boasts the world’s largest recorded unbranched inflorescence, or flowering stalk, which can grow as tall as 12 feet. Cornell’s maxed out at 66.5 inches, growing on average two inches a day leading up to its full bloom, according to Andrew Leed, greenhouse manager for the Cornell University Agricultural Experiment Station.

The titan arum also exhibits the world’s largest corm, a short and swollen underground plant stem from which the plant grows. Typically, its corm weighs about 50 kilograms but can weigh up to as much as 91 kilograms.

“We didn’t get to weigh [the corm] before this flowering event,” Leed said.“But we do know that it just about filled the bottom of the pot it’s in. It had to be at least 20 pounds and could have been considerably heavier than that.”

Most outlets have reported Cornell’s as the approximately 140th blooming of a  titan arum in cultivation; however, university Prof. Melissa Luckow, plant biology, contests that number.

“I do not know what the real number is but I do know that there were at least 157 back in 2008,” Luckow said, citing a since discontinued University of Wisconsin archive of  titan arum bloomings. Though exceedingly scarce before the mid-1990’s, the record shows that the frequency of such bloomings has exponentially increased in recent years.

“More and more people are getting seeds and learning how to grow them,” Luckow said.

In fact another  titan arum bloomed just last week in Kiel, Germany; making this the “week of the reek.”

“But it’s still not common,” Luckow added.

Niklas clarified in an email that the number of titan arum blooming in cultivation is still probably under 200, “which pales in comparison to how many times you and I have seen daffodils flower in our lifetime.”

Corpse Plant Research

In the height of their bloom, titan arums heat up to waft their foul perfume through the jungle air. Leed took thermal images of the inflorescence using an infrared camera to see how much heat the plant puts out and at what times. The tip of “Wee Stinky” reached 107 degrees Fahrenheit at its maximum. Even more images came from Prof. Kenneth Simpson, clinical sciences, who performed an endoscopy by looking down into the inflorescence to get close-up images from inside the arum.

Thermal examination was only part of the research that university scientists had the oppurtunity to perform while the plant was in bloom. Prof. Robert Raguso, neurobiology and behavior, and several graduate students collected samples of the plant’s stink to analyze the volatile compounds that compose it.  But scents from the colognes worn by the thousands of onlookers made it harder to obtain accurate data.

“We got some coconut lactones on the first day which I was skeptical about,” Raguso said. “Someone must have smeared piña colada on their arms.”

Amidst less than perfect research conditions, the scientists still found that the smell of decaying protein, dimethyl trisulfide, peaked Sunday evening. “To get the best data we would have sealed off the plant,” Raguso said, “but we wanted to show people. This was just too rare and precious of a thing to selfishly keep amongst ourselves.” A preliminary analysis of their data, which gives a sense for what the plant smelled like and when, is available here.

A Decade of Care

The University currently possesses two titan arums: “Wee stinky” and one which is currently in a vegetative state. Both of the plant came from the University of Wisconsin at the request of Luckow where  she attended a botanical conference as a plant was growing there in 2002, Luckow said.  Greenhouse manager Carol Bader then grew and cared for them over the course of the next 10 years. The University’s titan arums had to survive the transition from their former home in the Liberty Hyde Conservatory (which was condemned Oct. 15, 2010, due to health and safety hazards) to their current one in the slightly drier Kenneth Post Greenhouse.

“[Bader] deserves the lion’s share of the credit for keeping this thing from seed to reproductive adulthood,” Niklas said.

“These plants are not easy to grow,” Luckow said, “She pulled the rabbit out of the hat.”

Future Corpse Plant Cultivation

In the wild, even with the scavenging insects available to help, there is a slim probability that two such plants would bloom at precisely the right times and places for cross-pollination, Niklas said. The plants in cultivation, however, can be artificially inseminated.

Gwynne Lim grad, and Monica Ramirez grad, plant biology, and Ha Nguyen grad, neurobiology and behavior, hand-pollinated “Wee Stinky” with pollen given to them from Binghamton University’s 2010 titan arum blooming. The grad students cut square holes in “Wee Stinky’s” spathe — the dried-blood colored leafy, corrugated skirt surrounding the central spadix spike — to access and fertilize the plant’s female flowers. If the pollination was successful, the plant will produce many small bright red fruits containing three seeds each about seven to nine months from now.

Ramirez and Nguyen also managed to scrape and scoop about a teaspoon of pollen from “Wee Stinky” early Tuesday morning, staying up from midnight to four p.m. to do so, they said. That pollen is now being cryogenically preserved for future cultivated titan arum pollinations.

Cultivation is important for the plant since “Indonesian forests are really disappearing quickly,” Luckow said. Practices such as illegal logging, the development palm oil plantations, and the digging up and selling of titan arum corms on black markets now threaten the species — making wild titan arums ever scarcer.

In case you missed out on the bloom over Spring Break check out our slideshow of the event, and for those who wish to experience the bloom without the “blech” a time-lapse movie is also available.

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Original Author: Bob Hackett