Botanists with Blowtorches Try to Save Endangered Shrubs

If the blowtorch doesn't work, let's try sulfuric acid. Those seem to be strange words coming from botanists, including Old Dominion University faculty member Lytton Musselman, who are trying to save the critically endangered Michaux's sumac, one of the rarest shrubs in the Southeast.

An article about the declining shrub, written by Jay Bolin, one of Musselman's former students who received a Ph.D. from ODU in 2009, Marcus Jones of the Norfolk Botanical Garden and Musselman, appeared late last month on the Smithsonian Science website (http://smithsonianscience.org/2011/09/endangered-sumac/). The article had appeared originally in the Summer 2011 issue of Native Plants Journal.

So, what's this about a blowtorch? As it happens, the thickly coated seeds of this native North American plant are nearly impossible to germinate. Because Michaux's sumac grows only in areas with few trees where the vegetation has been disturbed, it has long been assumed that its seeds germinate naturally following exposure to the high temperatures of wild fires. The plant's endangered status has been attributed to the prevention and suppression of forest fires by humans.

In Virginia it has two known stands: on the grounds of the Virginia Army National Guard Maneuver Training Center at Fort Picket and a mowed railway right-of-way in an undisclosed location.

But the researchers report that they have exposed the seeds to boiling water, dry heat up to 284 degrees Fahrenheit and flames from a propane blowtorch to try to coax them into germination. Nothing seems to work.

"Complete understanding of the germination requirements of endangered plants is an absolute requirement to effectively manage populations," said Bolin, a former research associate with the Department of Botany at the Smithsonian's National Museum of National History who recently became an assistant professor at Catawba College in Salisbury, N.C.

Sulfuric acid, as it turns out, is far superior to a blowtorch. The scientists were able to get a 30 percent germination rate from seeds that had been doused with the acid. They are exploring the hypothesis now that the sturdy hull is eaten away when the seeds pass through the digestive system of birds.

Bolin said the researchers plan to feed the seeds to quail and wild turkey to determine if that breaks the seed dormancy. Seed passage through the digestive tracts of fruit-eating birds - with exposure to the acid in the birds' stomachs - may break the physical dormancy of these seeds and help disperse them as well, the scientists write.