Making botanical progress

Science: Assistant professor Douglas Darnowski and his students have found a way to reproduce carnivorous plants in the laboratory.

May 03, 2001|By Heather Dewar | Heather Dewar,SUN STAFF

CHESTERTOWN - These are the makings of a scientific breakthrough: a bicycle pump, a jug of water, some rubber tubes, a paint can stuffed with moss and a match.

With these low-tech tools, Washington College biologist Douglas Darnowski and his students have figured out how to do something science has never done before - something the squeamish might think should never have been done at all. They found a new method for expanding the world's population of killer plants.

Darnowski calls them "fatal flora," and he is their bespectacled, balding Dr. Frankenstein.

Since his days as a biology student at Yale, the 30-year-old assistant professor has been fascinated by the treacherous traits of some plants. His first love was the trigger plant, which may or may not be a bug-eater but definitely is a bug-beater.

When an insect settles on its delicate-looking flowers, the trigger plant releases a pollen-laden arm that bonks the poor critter on the head. When the insect comes to its senses, it makes its getaway - laden with pollen - an unwitting assistant in the plant's reproductive scheme.

Darnowski soon moved on to more ruthless flora: the Venus flytrap, which clamps its toothy green maw shut on unsuspecting flies, then drenches them in acid. The bladderwort, which looks like a water weed, is equipped with floating traps that can suck in a water flea in 1/30th of a second.

With that kind of allure, there's a ravenous collector's market for carnivorous plants, Darnowski says.

Maryland's 10 native varieties of carnivorous plants are either available commercially - like the rare purple pitcher plant, which is protected in the wild by state law - or less sought-after, like the half-dozen species of bladderworts that thrive in the bogs and swamps of the Eastern Shore.

But in parts of Asia, collectors are threatening to wipe out wild populations.

To help relieve the pressure on wild populations of carnivorous plants, the professor is trying to figure out how to reproduce several of the most spectacular species from Asia and Australia, the global center of killer plants.

"There are places where you can't put a foot down without stepping on one," says Darnowski. "Some of them are just flat out beautiful, like the sundew," which traps insects in sticky dew on its leaves. "To see them in the morning when the sun hits the little drops of goo," he says, "they're just exquisite."

Among his other specialties are aldrovandas - underwater versions of the Venus flytrap that eat water fleas - and a delicate butterwort with lovely purple flowers and lethal, sticky leaves.

Fortunately for the insect kingdom, most carnivorous plants are not very vigorous. Bug-catching burns up a lot of energy, and under normal conditions they'd be outgrown by plants that rely on photosynthesis for food.

The carnivores thrive in nutrient-starved environments - usually bogs and swamps where low water flows have created conditions too acidic for plants to decompose naturally. When that cycle is interrupted, there isn't enough natural fertilizer for most plants. That gives the bug-eaters an advantage - they can chow down on insects.

In the lab, getting the carnivores to reproduce can be tricky. Even when exposed to ideal light levels and fed on Darnowski's specially developed diet of agar, vitamins, salt and sugar, the seeds may simply refuse to germinate. When dosed with a powerful plant growth hormone, only about 2 percent germinate.

But last year, Darnowski had a brainstorm. Many of the carnivores grow in places that are frequently burned by wildfire, and plants that are native to that kind of landscape often need fire to germinate their seeds. What if the professor and his students could bottle fire and feed it to their plants?

Darnowski helped Washington College student Leora-Leigh Ramiro rig up a smoke-bottler.

They stuffed a paint can with moss, then ran tubing that connected the can to a bicycle pump on one side and a beaker of water on the other. They set the moss on fire, slapped the lid on the paint can, and used the bicycle pump to feed in enough air to keep the fire going.

The smoke from the can percolated through the water, which soon looked "like strong tea," Darnowski says.

They then doused trigger plant seeds with the liquid smoke and got 10 percent to germinate - "not a huge improvement, but a real one," Darnowski says. "And the students got a kick out of it."

One of Darnowski's goals is to get his students interested in scientific research, and the bug-eating plants are perfect for that, he says. Several students regularly volunteer to go swamp-tromping and canoeing through a nearby bog where four types of bladderworts are known to grow.

Darnowski has found three of them, accessible from a primitive boardwalk on private land. But you can't hike off the trail. The bottom is spongy with layers of old sphagnum moss, treacherous as quicksand.

One day, Darnowski says, he'd like to pull on waders, climb into an inner tube, tether himself to the boardwalk by a rope and wade into that bog until he finds the fourth variety of bladderwort.

All he needs, he says, is someone to reel him in.

Baltimore Sun Articles
|
|
|
Please note the green-lined linked article text has been applied commercially without any involvement from our newsroom editors, reporters or any other editorial staff.