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Johnson Begins Fulbright Research in Thailand for Worldwide Monograph


December 18, 2002

[ Xylopia Annonaceae Photo ] DELAWARE, OHIO -- Ohio Wesleyan botany-microbiology professor David Johnson has received a prestigious Fulbright scholarship and will spend six months -- from January through July -- in Thailand and surrounding areas. He will conduct research and writing about Xylopia (member of the Pawpaw or Soursop family) Annonaceae (technical name of the family), a particular genus of tropical plants that, as he says, "currently fascinates me."

Johnson has conducted similar research in Eastern Africa as part of a previous Fulbright award as well as tropical America. The duration for his on-site stay is as important as the locale.

"With plants, it is important to be available for field research until it rains and there has been enough time for the plants to ripen and mature," says Johnson, noting that the plants don't always bloom in the summer. His field work will involve collecting specimens, making notes, and gathering fruits and flowers in alcohol to maintain a three-dimensional appearance of the flowers and fruits of Xylopia. Johnson also will collect leaf tissue in silica gel for later DNA analysis by fellow researchers. He now knows from the study of museum specimens that there are at least 10 new species of Xylopia which are unknown to science. He plans to describe them for general scientific literature in much the same way that he will contribute his research findings to a worldwide monograph series, while in Thailand.

The project in Thailand is designed to provide encyclopedic reference for all Annonaceae, not just Xylopia.

"The goal of this work in Thailand is to document and reference much-needed information involving 200 species of this genus," explains Johnson. "In order for me to write a worldwide monograph for these plants, I need to see them in their native environment, rather than relying on second-hand information." He wants to find out what they look like, where they live, what organisms depend on them, how the flowers are pollinated, and how the seeds are dispersed to other locations. But beyond the obvious, there are unanswered questions about tropical plants that attract the curiosity of many scientists, including Johnson.

"We also wonder to what extent are these 'ancient' plants, millions of years old, as opposed to being more transient and widely dispersed," questions Johnson. "How did these present-day organisms get to the places they are today?" In Southeast Asia, for example, there are several species of the Xylopia genus and a few additional ones in New Guinea, Northern Australia, New Caledonia, and Fiji. But in between those locations, there are huge expanses in which there is no present-day evidence of Xylopia. Johnson surmises that they got to New Guinea through Australia, and to Southeast Asia by way of Europe and Asia. Or perhaps the plants traveled to Southeast Asia and New Guinea in one direction and then later disappeared from the center region. Studying these patterns will enable Johnson to learn more about Xylopia and how the various species relate to each other. His work also will provide much needed data on plant life in that part of the world.

"We have more affinity for organisms that are most like us -- the warm-blooded creatures," says Johnson, pointing out that there are 300,000 species of flowering plants in the world and 9,000 species of birds worldwide. "Yet people are more aware of the numbers and kinds of birds living in various parts of the world," he says. "It is just a matter of breaking new ground."