MacArthur Genius: "Plants Have Souls"

"This year's class of MacArthur Fellows is an extraordinary group of individuals who collectively reflect the breadth and depth of American creativity," said Cecilia Conrad, vice president of the MacArthur Fellows program, in a press release announcing the 2013 recipients on Wednesday. "Their stories should inspire."

Over the next few days, we will profile some of these innovative people in this series, "Interview With a Genius."

C. Kevin Boyce claims he doesn't have a green thumb, even though he studies plants for a living.

"I don't!" he insists. "I know other paleobotanists who do, but I don't."

But few other paleobotanists can claim to have just won one of the premier honors in the intellectual arena—Boyce is a recipient of a 2013 MacArthur "genius grant."

The Stanford professor of geological and environmental sciences is part of a small but influential group of paleobotanists, folks who study ancient, fossilized plants to find clues to evolution and climate patterns from millions of years ago.

"Plants Have Souls"

It wasn't until Boyce was in graduate school at Harvard for paleontology, studying evolution and development of life-forms, that he realized he might have a green thumb of a different sort.

"I wasn't a plant person from birth or anything," Boyce said. "[But] plants have unique characteristics that allow those kinds of studies ... They have cellular preservation."

Cellular preservation means that fossilized plants remain intact and reveal the internal function of flora from millions of years ago. That unique preservation answered some of Boyce's nagging questions about evolution in a way studying animals couldn't.

"It's more difficult with animals," Boyce said. "A clamshell is a clamshell. With dinosaur bones, you can't look at soft tissues around the bones.

"But with plants, you have cellular anatomy preserved. Every plant cell has a strong cell wall. Plants have souls that animals don't—it was pretty literally that."

Strong cell walls are a key to understanding evolutionary biochemistry because they preserve organic matter. The organic matter, in turn, provides valuable clues into not only the age of the plant but also how it functioned.

Climate Change Clues

But what are those clues?

It might help to think about plants as a thermometer, a sort of indicator of the climate around them.

For plants, water processing is a vital process—moving water throughout its internal system, a process called transpiration, is crucial for survival. Remember how your houseplant looks without some water over the course of several days? Dry, perhaps brittle at the edges?

That plant is indicating that it's not doing too well and that the atmosphere has become somehow unfit for it.

Boyce says a plant's veins reveal these kind of effects to scientists.

"If a plant is trying to take in carbon dioxide but can't [do so easily] without losing water, there is a higher density of veins," he said.

In other words, if the climate gets hotter, plants display more veins to aid its transpiration process—a pattern that is now increasingly being seen in areas of high deforestation, such as the Amazon rain forest.

According to Boyce, the evolution of plant structure and its relationship to the climate is a two-way street.

"If they're capable of losing more water, it changes climate," he said. "If you look at the tropics, just based on physical geography, there will always be a rainy belt. It's based on vegetation. And it's this that dominates the tropics. If you cut down the forests, you're degrading the precipitation that's sustaining the environment."

This pattern of a response cycle in venation and climate doesn't occur just in rain forests, Boyce said, pointing to evidence in colder regions and at higher altitudes that venation has changed because of rising temperatures.

The past is an indicator of the present—and future—of natural life.

"If you went back 150 million years ago, the rain forest wasn't working the same way," he said. "[Without fossilized plants], you can't understand the modern environment."

Though his research on the environment has far-reaching effects, Boyce says that he is a paleobotanist first and foremost, and that the study of fossilized plants is his focus.

"I'm not an ecologist," he emphasized. "I kind of do what I enjoy the most. I'm not a climatologist either, but I'm interested in teasing out the lineage here and what it tells us."

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