Harvesting Ideas

Ward now studies climate change in her lab, having traded picturesque cavesicles for a treasure trove of plants, including the model organism Arabidopsis as well as prehistoric specimens retrieved from the La Brea tar pits in Los Angeles. Figuring out how these plants—both living and preserved—have responded to atmospheric carbon dioxide has given Ward a window into how the biosphere can adapt to an environment that continues to evolve. Here she talks about participating in plant science’s coming-of-age, collaborating with pack rats, and collecting presidential hugs.

On Ward and Upward

Legacy. “When I was seven years old, my father gave me the microscope that he had used in medical school. This made me really love science from the start.”

The two faces of CO₂. Ward began to study the effects of rising carbon dioxide levels on plant physiology and development as a graduate student at Duke University with Boyd Strain. “We would expose plants to high CO₂ and measure what happened. CO₂ is the substrate for photosynthesis, so with high CO₂ you often see stimulation of photosynthesis and reproduction. But we also know that in the field, rising CO₂ also causes warming. And as you warm plants up, they have higher respiration rates, which can actually reduce some of the gain in carbon they accumulated from the high carbon dioxide.” So the effects of CO₂ can be positive and negative—and even unexpected. Ward conducted a study to examine how plants might evolve to adapt to conditions of elevated CO₂. She grew Arabidopsis in concentrations of CO₂ that were either as high as predicted for the future or as low as has been measured in the past. She then selected and bred the individuals that produced the most seeds. After five generations, she found that the plants that were most fecund under high-CO₂ conditions had sped up their life cycle. As a result, they actually produced less biomass than plants that were picked from the population at random. “That was not what I expected,” says Ward. “I thought that plants selected for high seed number under high CO₂ would be much larger. But they weren’t. That suggests that genetic change is possible even in a relatively short amount of time—and that the way plants respond to rising CO₂ can be surprising.”

“We need to do a better job as ecologists of taking our studies down to the molecular level. Rather than just measuring that these things are happening, we need to know why they’re happening.”

Seeding the field. “It tickles me to see so many labs now working on evolutionary questions relating to CO₂. I think that original study (published in Oecologia in 2000) spurred a lot of new research into how genetic change can alter responses to increasing levels of CO₂.”

Old wood tells a tale. As a postdoc at the University of Utah, Ward received a generous donation of well-preserved plant samples excavated from the La Brea tar pits. “When you think about the tar pits, you think of saber-toothed cats and all these wonderful glacial mammals,” she says. “But there are also leaves and wood in the tar pits. The curator of the La Brea fossils, John Harris, was very generous in letting us study this plant material, because very few had studied it before.” Ward was hoping to explore how plants adapted to the low CO₂ concentrations prevalent during the last glacial period, 20,000 years ago. Conducting carbon-isotope analyses of the wood and using ice-core data from the period (the latter a reflection of atmospheric carbon), Ward and her mentor, Jim Ehleringer, determined that the glacial plants were likely carbon-starved compared to modern trees. “They probably also had a much slower growth rate compared to today—and that could affect plant availability for animals as well,” she notes. “So I think it’s really critical that we do study the plants. The animals are wonderful and exciting. But the plants can give us a sense of how the ecosystem was operating during glacial periods.”

An eye on the past. “Because I’m studying genetic change in plants associated with rising CO₂, I could focus on what conditions will be like in the future. But I think we learn more when we also look to the past. Because, although climate change and CO₂ changes were much slower in past than they are now, plants did evolve and respond to those changes. And I think that has provided us with insight into what could happen in the future.”

Thank you, pack rats. Ward has inherited perhaps the world’s finest collection of materials harvested from the burrows of pack rats (the Philip V. Wells Middens Collection). “These are the real animals—not the people who have a lot of stuff. Pack rats collect everything, and in desert areas they bring plants into their burrows as future water reserves.” These well-preserved samples, some of which are tens of thousands of years old, are giving Ward and her colleagues a feel for how the physiology of the local foliage has changed between the last glacial period and the present.

Show me the molecules. At the University of Kansas, Ward has been following up on her thesis work and trying to isolate the genes responsible for altering the life cycle of Arabidopsis in the presence of high CO₂. One key player is a master regulator, the floral repressor FLOWERING LOCUS C or FLC. Ward found that plants adapted to grow in high CO₂ bloom later because the FLC gene remains highly expressed, thus suppressing flowering. “So we’re seeing a direct effect on the floral initiation pathway due to the environmental effects of CO₂,” says Ward. “That’s pretty critical because CO₂ is rising globally, so all plants are experiencing higher levels. This is a mechanism we’ve got to get a handle on.” The timing of plants’ flowering can affect their seed production, overall growth, and ability to take advantage of the pollinators upon which they rely. “We need to do a better job as ecologists of taking our studies down to the molecular level. Rather than just measuring that these things are happening, we need to know why they’re happening.”

“Climate change is a scientific issue. I think it’s a tragedy that the subject has become so politicized.”

Supporting success. The University of Kansas is notable for hiring female biologists who turn out to be incredibly productive. Ward credits this success to university policies—having a child extends the tenure clock by a year—and to the pioneering women who paved the way. But she also recognizes the benefits of collegiality. “The women in our department are extremely supportive of each other—to the point where you donate your baby clothes to the next parent down the line. We show each other our successful grant applications so the new hires can see what works. We get together for lunch. It’s just a very close-knit group of women who care about each other’s success. When one of us is successful, it’s a success for all of us. And I don’t know how often you find that sort of support.”

Climate Change 101. Ward teaches an undergraduate course on global change, which covers topics like climate change, land usage, and genetically engineered crops. “I present the scientific information and we have a group discussion,” she says. “Whether they choose to believe it is up to them. But at least they’re seeing the data and understanding the concepts. Climate change is a scientific issue. I think it’s a tragedy that the subject has become so politicized.”

A Word with Ward

All or nothing. “When graduate students ask me for advice, I tell them you have to do this all the way. It’s not just an eight-hour-a-day job. You have to put in the time to do great research and to develop your writing and presentation skills. If you want to be a professor and make it to the top, you have to make that decision as you begin graduate school. Because to come out of graduate school as a good researcher, a good writer, and a good speaker who knows how to think—that takes total commitment.”

Boldly go. “When you have a good question, don’t get held back by the historical limits of your field. You need to branch out of areas that are familiar and to learn whatever new techniques you need to answer the question.”

The joy of seeds. “What’s wonderful about plants is that the seed stage is something you can keep alive with minimal effort for a long period of time. They’re not like animals, which require a tremendous amount of maintenance just to keep them alive—like the fruit flies my husband, Robert Ward, works on. So having a seed stage reduces your workload as a scientist by several hours a week at least.”

Plant science pays. Ward has noticed an uptick in funders’ interest in plants. “The realization is being made that we have to understand how plants are responding to a changing climate so we can address our environmental issues. I think the investment in plant science is coming at the right time and it’s a pleasure to see.”

Model of efficiency. “I make use of very small blocks of time. Two minutes here, three minutes there is an e-mail or two that I can get done. I can even use a couple minutes to touch base with students on their progress, see how things are going.”

Most valuable player. “Sports probably has more influence on society than science does. So I think awards are good, because there are superstars in science, just like in sports. Seeing scientists win prizes for their work lends validity to the enterprise and shows that these people are respected and have accomplished great things.”

Home ward

Arm-in-arm with presidents. As a teenage guide, Ward fielded questions from former President Jimmy Carter during a surprise visit to the cavern. “I was shaking the whole time,” she says. “I was just a kid—16, in fact. But he was very, very nice and gave me a big hug at the end.” Then in 2010, when Ward collected a Presidential Early Career Award for Scientists and Engineers at a White House ceremony, she took home a group photo in which she stands arm-in-arm with Barack Obama. “When the photographer said to move over and leave a space beside me, I knew I was good,” she laughs.

Revisiting a classic. “I recently went back and read the diary of Anne Frank and I found it amazingly inspirational. Here was this girl who had the stamina to remain strong through remarkable adversity. And she had such enthusiasm for her future. Reading the book now, as a parent, also gave me insight into how teenagers think. It reminded me how extreme their emotions are. And how much time they take to think about how they feel. She was such an impressive kid. The world would have been a better place if she’d survived to fulfill her dreams.”

Outsource. “One thing as a woman scientist you need to do is to get help. Get help with your housework or with whatever you need, so you have time with your kids and time for your science. Kate Freeman from Penn State gave me that advice and I will never forget it.”

Worth the effort. “This job is harder than it looks. Of course it’s also very rewarding. So I’m kind of glad no one told me how tough it would be. Because I wouldn’t trade it for anything.”

How was your day? “My husband is a developmental geneticist. But we try not to talk about science at the dinner table. We rather enjoy finding out what the kids are doing and what happened at school, and just being together.”

Abbondanza! “I love to cook Italian. You have to make your spaghetti sauce every Saturday afternoon. Don’t overdo it with a lot of herbs. Just use garlic and oil. And lots of red wine! Then cook it on very, very low for 7 or 8 hours. If you divide it up and freeze it, you have decent meals for your family for a couple of days.”