A research project that Spencer Eusden ’12 worked on his senior year at Bowdoin has culminated in a publication in New Phytologist, a prominent academic journal that covers developments in plant science.

Eusden worked with a team of four researchers from the University of Idaho and biology professor Barry Logan, who is also Bowdoin’s associate dean for academic affairs. Together they discovered that a long-distance laser can remotely sense whether plants are under stress. Their findings could potentially have a big impact on agriculture by reducing farmers’ chemical and water use, as well as further our understanding of how plants cope with environmental change.

The Breakthrough
Traditionally, plant physiologists have been able to measure levels of plant stress only by conducting close-up tests on a leaf. On the other hand, lasers that can measure distances while mounted on aircraft or satellites have been used in the field of plant science mostly to create 3-D models of agricultural or forest canopies.

The work by Logan and Eusden, along with collaborators Troy Magney, Jan Eitel, Jingjue Jiang and Lee Vierling, exploits a new use for remote sensing lasers. In a way their finding marries the small-scale work of a plant physiologist with the broader scope of a landscape ecologist. “It’s one thing to know where leaves are in space. It’s another to know whether these leaves are experiencing stress,” Logan said. Plants experience stress when they have too much light or too little, too few nutrients, too little water, too much heat, etc. Stress interferes with photosynthesis, changing the biochemistry of a leaf, and this can be measured. Read more about the science.

While Logan and other plant physiologists have been able to measure stress-induced changes on leaves, the possibility of scaling their measurements up by analyzing many plants at once is an exciting one. “You can scan a wheat field to get a sense for whether one portion of the field is more stressed, and thereby narrow your treatment of fertilizer,” Logan said. “Farmers hedge their bets, so they’ll irrigate or fertilize a whole field. This could help them customize and streamline irrigation and fertilization.” This new use of laser technology could also help scientists understand how native forests cope with our changing climate.

Spencer Eusden’s Role
When Eusden, a biology and environmental studies major who graduated with honors, approached Logan about doing a senior year honors project in 2011-2012, Logan asked whether he would be interested in working with remote-sensing lasers. Eusden said he jumped at the chance to study plant systems on a large scale.

Eusden received a Grua/O’Connell research grant from Bowdoin to travel to Moscow, Idaho, in December 2011 to work with a team of landscape ecologists at the state university. He helped design and conduct an experiment with oak, aspen and birch saplings, sunflowers, and winter wheat plants to test the untapped potential of green-light lasers.

In Idaho, Eusden hunkered down in a dark basement with graduate student Troy Magney to collect data. “Over six days we both spent almost 70 hours in one room of a basement,” he said. “Normally I would not be able to handle spending that much time inside, but I had a great time throughout the experiment.”

After returning to Bowdoin, Eusden analyzed the data to write his honors project. Following graduation, he continued collaborating with the team to help write the article. The experience was so positive that both Logan and Eusden predict the group will come together again, most likely to test their theory in the field and take stress measurements of wheat growing in Idaho.

“Spencer was a roll-up-your-sleeves type of student,” Logan said. “He was certainly the right student to do something like this. He’s really strong on follow-through, and stayed motivated even after graduation.”

Eusden said the experience cemented his interest in graduate school. But before he starts his studies, he’s pursuing another goal: to make the U.S. nordic ski team. The South Paris, Maine, native skied for Bowdoin’s X-C team for four years. At the moment, he’s living in Truckee, Calif., training with other elite skiers.

“While I plan to compete in the Olympic qualifiers this year and do my best to qualify for them, realistically my best chance would be for the 2018 Olympics in South Korea,” Eusden said.