To the naked eye, the leaf of an Arabidopsis plant looks like a leaf and feels rather soft. But put it under Whitman College’s new $408,000 scanning electron microscope (SEM) and new worlds of seemingly dangerous spikes and puckered lips are revealed.
That was the “show and tell” at a recent open house in the science building at which the National Science Foundation-funded SEM was unveiled to the campus community.
The SEM magnified a single leaf hair about half the diameter of a fine human hair and less than half a millimeter long 300 times. With the sharp resolution of the SEM, that plant hair or trichome looked like a pronged tropical plant of a size that filled much of the 8 ½ by 11 sheet of paper. But more than the fascination factor of the visual image was what it means for the college’s students and researchers.
Whitman students will now have the opportunity “to be trained as working scientists” using an instrument that has become the “workhorse of the geology and biology research communities,” said Kirsten Nicolaysen, assistant professor of geology at Whitman and a driving force behind getting the SEM. She has spent much of her spare time with the new instrument since it was taken out of the crate.
Nicolaysen already has several students lined up to use the SEM starting in January for such research as characterizing the host basalt for a carbon sequestration pilot project, two projects investigating the history of volcanic eruptions in Alaska and the local Columbia River plateau, and a project that will investigate the ties between the sedimentary record of Greenland glaciers and climate change.
Other departments plan to use the SEM. Gary Rollefson, professor of anthropology, has found fiber in an 8,000-year-old plaster wall excavated in Jordan last summer that he wants to magnify and identify.
Kate Jackson, assistant professor of biology, says the instrument “is expected to yield discoveries in many fields. Advances in basic genetics and neuroscience will result from the capacity for imaging hydrous biological samples such as mutant plant embryos and brain cells. New understanding of the evolution of vertebrates including early humans (because of) the spectacularly clear imaging at a broad range of magnifications of fossil fragments, snake fangs and prehistoric tools. And the ability to spatially map composition of geological materials is expected to enhance current knowledge of how volcanoes function.”
The new microscope replaces a 1970s model that used Polaroid film, which is no longer manufactured. No longer able to obtain replacement parts, good digital images, or any compositional X-ray data for minerals, the coalition of geology, biology and anthropology faculty members sought NSF funding to replace an instrument critical to faculty research. Dan Vernon, professor of biology, said that to attempt to get useable images with the old SEM took “days” and extensive preparation of samples, coating them with carbon and other treatments, hoping samples didn’t deteriorate — a process akin to “voodoo artistry.” In comparison, with the new SEM, a sample is simply placed on an interior platform in the SEM, the door closed and then the researcher, while watching the sample on the computer monitor, begins the magnification process. The SEM’s “huge range of magnification” provides resolution for samples as small as three microns, professors shared. Moreover, biological cells – like those in the plant leaf or neural cells – stay plump and retain their form, more accurately showing changes in their DNA; in the past the cells would lose water and shape like a balloon with a slow leak.
Vernon said the NSF’s approval of the grant is testament to the strength, the “critical mass,” of research being conducted at the college because NSF’s focus is research. It doesn’t “give grants just for ‘teaching’ purposes,” he said.
The instrument, designed in the United States and Holland, and built in Czechoslovakia, also will be available to other area educational institutions and students, Nicolaysen said.
— Virginia Grantier