A New Way to Look at Plants

Students of Assistant Professor of Biology Jonathan Wilson are getting the chance to look at plants in a whole new way thanks to a grant that has helped him add an advanced piece equipment to his lab.  In October, Wilson, a biologist whose research uses fossil plants to reconstruct environmental history, was awarded a $49,000 matching grant from the Li-Cor Bioscience Environmental Education Fund to buy a portable infrared gas analyzer, which measures rates of photosynthesis.

“It is particularly impressive that Jon applied for this grant while still unpacking boxes in his new lab,” says Karl Johnson, professor and chair of the biology department. Johnson says the machine will be a valuable tool for students in the Bio 300 course, also known as Superlab, and in the photosynthesis class Wilson introduced for the spring semester.

“Haverford hasn't had anything like this before,” says Wilson who joined the faculty at the start of the current academic year to help build the new Tri-College Environmental Studies Program.“It's a pretty standard piece of equipment for plant physiologists, and for big agriculture companies that need to know how their corn, or soy beans, or grapes are doing.” But the system is not often part of the inventory at a small liberal arts college.

The infrared gas analyzer (or, IRGA) has two parts. One is a sensor that clips onto a leaf and measures how much carbon dioxide the leaf is taking up, as well as other parameters like temperature and relative humidity. The other part is essentially a metal box that houses pumps, a chamber and a computer that does the calculations.“It's possible to learn all of this information in other ways,” says Wilson.“But they're a lot more labor intensive and therefore can leave the door open to errors or mistakes.”

“What's also nice about the system is that conditions can be adjusted in real time,” he says.“You can flood the leaf with CO2 and see photosynthetic rates go up. You can lower the light on the leaf and watch the rate go down.”

With help from the Arboretum staff, four Haverford biology majors are utilizing the system in their senior thesis project research, Wilson reports. Rebecca Tobet, is looking at a class of primitive ferns, called horsetails, that first appeared in eastern North America 300 million years ago, to learn the source of structural support in their extinct tree-sized relatives.  Anna Rayne is doing growth chamber experiments, to explore how plants function under long-term drought conditions with high CO2 levels. Emily Dutrow is examining how plants respond to simulated grazing, to answer questions about destructive over grazing.  And Kelsey Capron is studying the comparative physiology of leafless ferns. 

“This is all stuff that will help us think about the future of a world with much higher CO2 levels as well as changes in water and rainfall,” says Wilson. “Figuring out how plants solve problems is important work, and it is really helpful to have a piece of equipment that is so easy to use and gives you a lot of data for not a lot of effort.”

—Eils Lotozo