Tuesday, May 29, 2001

Biologist works to save the violets


Their population in Africa is shrinking, but Valerie Pence of Cincinnati Zoo is determined to preserve this popular plant

By Jim Knippenberg
The Cincinnati Enquirer

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Dr. Valerie Pence is looking for ways to save African violets
(Craig Ruttle photos)
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        Valerie Pence doesn't look like Mr. Wizard, sitting there in her standard issue chinos and blue sweater. But if you're an African violet, she is Mr. Wizard.

        The African violet in the wild is teetering, highly endangered and headed for extinction if something isn't done.

        It is hard to believe. You don't have to be Mr. Wizard to know that African violets dot the American landscape in numbers massive enough to make them a $30 million a year industry.

        But this is different. In the first place, those aren't true violets. The purpling of America is due to Saintpaulia ionanthaand its hundreds of hybrids. True violets are of the Violaceae family.

VIOLET'S HISTORY
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  The African violet was almost completely unknown to Western science until 1892, when Baron von St. Paul, governor of Tanzania (it was Tanganyika then) sent a batch of plants to Germany's Royal Botanical Gardens of Hanover.
  There, one Herman Wendland wrote the first scientific description and gave them the name Saintpaulia ionantha.
  It wasn't until the 1930s that horticulturists went to work on S. ionantha and developed strains suitable for home gardening. Since then, hundreds of hybrids have been developed.
  Today, they're a $30 million a year industry.
  But they aren't really violets at all. They're the right color, but they're really members of the Gesneriaceaefamily. A true violet is of the Violaceaelineage.
        By whatever name, the bottom line is the same: There are more than 20 species of Saintpaulia growing nowhere but Africa, and all of them have been categorized by the World Conservation Union as endangered or threatened.

        The problem is habitat shrinkage: The African violets in question grow on rocky cliffs and slopes in the shade of the rain forests of southern Kenya and northern Tanzania. But the rain forests are disappearing — due to logging — and with the trees go the shade these plants so desperately need.

        One of them, S. rupicola, is the primary species Dr. Pence is working with and so critically endangered there are only four populations left, one which has only three plants.

        Somebody needs to figure out how to jump start a new population right now.

        Enter Mr. Wizard. Or failing that, Dr. Pence, plant biologist at the Cincinnati Zoo and Botanical Garden's Center for Research of Endangered Wildlife (CREW) since 1986.

        Dr. Pence, using plants and tissue supplied by Dr. Jeff Smith of Ball State University in Muncie, Ind., is a couple of months into a team project with James Madison University in Harrisonburg, Va., and the East African Herbarium of the National Museums of Kenya. They're all looking for ways to save the plant.

        And not the old-fashioned way, where some sticky-footed bug crawls around mommy and daddy plants and babies happen.

        Oh no. This method has Dr. Pence hunched over an electronic dissecting microscope, squinting at slides while wielding tiny sterile tweezers and filling Petrie dishes with things you can't see, such as a tiny embryo extracted from a seed. It's all set to the tune of a large humming hood to keep things germ-free.

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Dr. Pence uses tweezers to insert a subcultured Africa violet into a growing tube.
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        Behind and to the side of her run racks full of labeled test tubes and sterile dishes, some sprouting a bit of green, some just holding a tiny chunk of plant tissue.

        Dr. Pence already has succeeded in growing stems and leaves, but no flowers.

        “We're taking a couple of approaches to this,” she says in her CREW office. “One goal is cryopreservation, where we will freeze tissues in liquid nitrogen. We haven't gotten to the point where we can do it, but we will. Then we'll share the technique with colleagues in Africa.”

        She'll also put samples away in a frozen garden. As gardens go, this one isn't all that glamorous — six or eight stainless steel gaseous tanks full of plant matter. Think of it as an insurance policy: If the day comes when the plants are extinct, Dr. Pence can dip into her frozen garden, grab a tissue and start it up again.

        A second approach is working too. “We're doing well with in-vitro collection. That's where we take a tip off the plant, slip it into a gelled medium and wait. The tip grows into a main stem. We've done that many times.”

        The leaf tissue method also works, but it isn't popular. That's when a researcher uses a single-hole punch to take a piece out of a leaf. It then goes into a sterile medium and starts to grow. But it means destroying a leaf from an endangered species and scientists, well, they're squeamish about that.

        When all this is finished — it's open ended; maybe a year, maybe two, maybe 20 — the team will give the plants to their African colleagues and let them purple up the continent, right?

        Wrong. “We'll give them all the techniques we develop and then they'll collect from the wild. Then they'll repropagate from that population. With our plants, there's always a danger you're introducing something that doesn't belong there.”

        There are a couple of reasons to do this, she says, now leading a tour through CREW's steamy greenhouse. “There are so many species that aren't tapped into or grown. As with all plants we don't know much about, there could be other uses. If we lose them, we don't know what we've lost.

        “No one has ever found any hidden properties, but no one has ever looked.

        “And also, they play a role in their ecosystem. We don't know exactly what, so we don't know what happens to the ecosystem if they're lost.

        “But you really don't want to lose any part of the environment. The Conservation Union lists 33,000 species worldwide that are endangered. That's one-tenth of the world's plants.

        “People don't know that, and that's another goal of this project. By focusing attention on a well-known and beloved plant that's endangered, maybe we can raise awareness of other endangered plants.

        “And that's important because always you keep coming back to that one thing, because we don't know much about them, we don't know what we're losing. But it's probably a lot.”
       



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