WASHINGTON - A new exhibit at the U.S. Botanic Garden here puts a spotlight on the parts of plants typically hidden underground and out of sight.
Megan Freier, visiting from Kansas City, Missouri, wasn’t expecting much from "Exposed: The Secret Life of Roots."
"I was kind of like, oh, an exhibit on roots. How boring can this be?" she said, chuckling. "And then you walk in and, just, wow!"
Suspended at eye level are roots of dozens of native perennial grasses from the American prairie. Annuals such as wheat and corn hang with their roots exposed against both sides of a partition running down the center of a gallery. The roots are tangled and bushy, with their dried fibers stretching down several meters. The longest ones are rolled up at the ends and tied off so they don’t sweep the floor.
The display seems to grow out of a panoramic photo of a farmer’s field. It amazed Freier’s aunt, Louisa Baylan of Orlando, Florida.
"What shows on the surface is nothing compared to what is grounding them," Baylan said of the plants. She added that she and Freier were "kind of in awe about what it takes to support the growth above ground. I mean, I just had no clue that the roots went so deep."
Roots grown and excavated
The exhibit tapped the skills of Jerry Glover, who grew the plants at The Land Institute in Salina, Kansas. The agricultural ecologist used 3-meter-long sections of polyvinyl chloride (PVC) pipe and special clay material that enabled easy transplanting with the roots intact. Then the roots were soaked in a glycerin solution to prevent rotting.
Susan Pell, the Botanic Garden’s science and public programs manager, said this unexpected scene delivers a powerful message.
"Roots are the foundation for life" – and not just for plants, Pell explained. Roots absorb nutrients and water, which plants synthesize and make into sugars. "Plants themselves are really what we depend on as a species, whether we are eating them directly or we're eating animals that depend on them for food."
Outdoor portions of the exhibit offer more surprises. Pell picked up a soybean plant and pointed out its root system’s importance to soil: Soybean roots "have these little nodules on them, which contain a bacterium, which fixes nitrogen. That’s sort of a fancy way of saying it makes nutrients available to plants that otherwise would not be available to those plants."
When it’s not a root
The exhibit, which continues through October 13, explains that not everything growing underground is a root. For example, ginger and bamboo don't spread from roots but from rhizomes or continuously growing horizontal stems.
These "allow the plant to grow many, many stems above ground and to spread in vast areas," Pell said. "This is why we see bamboo forests. In some cases, actually, bamboo forests and also aspen forests may be a single individual that is entirely connected underground."
“Exposed” reveals a clearer picture of what plants need to survive.
The prairie grasses’ long roots illustrate how hard plants must work, and how much they suffer, in drought-stricken areas.
"If these roots have to go so deep into the ground and they need water for sustenance, you just really kind of wonder, are we going to be able to sustain agriculture?" Baylan observed.
Pell said she hopes visitors like Baylan leave with a new appreciation of natural systems and a sense of urgency to protect them from ever-pressing environmental problems.