Common scientific ground in plant physiology

Did you know that bamboo is a grass? Colorado State University ecophysiologist, Troy Oceltree is exploring how bamboo could shed light on local grasses’ plant structure and drought tolerance along with U.S. Department of Agriculture researcher Sean Gleason in collaboration with Guangxi University Professor Kun-Fang Cao.

Ocheltree, an assistant professor in the Forest and Rangeland Stewardship department, recently returned from a trip to Guangxi University in Nanning, China.

people in front of a rock with Chinese inscription
From left: Damien Hinsinger, Guo-feng Jiang, Troy Ocheltree, Sean Gleason in front of the College of Forestry building at Guangxi University.

Ocheltree specializes in understanding the mechanisms behind plant responses to and recovery from water shortages, with an emphasis on grasses. A common misconception he sees is that grasses can easily recover from water deficiencies but these processes are microscopic, making them difficult to observe and measure. The actual mechanism that scientists call “root pressure” may be more nuanced. In this process, plants generate water pressure in the roots that forces water up into the leaves and rehydrates them following drought.

“Root pressure typically helps the leaves recover from stress,” Ocheltree said. “but this hasn’t been tested across a range of species and conditions yet.”

Enter bamboo. Professor Cao focuses on water transport system and the evolution of drought tolerance in plants. He has begun identifying the mechanisms behind root pressure functions in this tree-like plant.

bamboo leaves
Understanding “root pressure” in bamboo may shed light about this mechanism in grasses.

Bamboo, a much taller and woodier grass, occupies wetter climates, a stark contrast from the species Ocheltree studies in the semi-arid, western Great Plains. However, he said understanding this mechanism in bamboo may shed new light on understanding the role root-pressure generally plays in a grass’s ability to recover from drought.

Ocheltree and his associates tested the hydraulic recovery system in bamboo leaves by simulating root pressure with pressurized water. The recovery was incomplete in these initial trials, which suggested a range of conditions may be necessary for plants to reclaim water transport processes following drought. Ocheltree said the shorter stature of grasses found on U.S. prairies would require significantly less root pressure than bamboo, but length may not be the only factor. Other environmental elements and land uses may affect the process as well.

“The next step would be to evaluate root pressure in important grass species in North America and evaluate how changes in weather and/or grazing may impact the ability of grasses to generate root pressure.” he said.

Incorporating similar tests on our side of the ocean can help reveal how grasses manage to thrive amidst the polarizing conditions found in America’s heartland, from floods to famine to freezing conditions. This information will be all the more important as his lab works to understand the implications of global climate change on local landscapes.

People on a mountain lookout
Troy Ocheltree, Jiang Gui-feng and Sean Gleason in Mulun National Nature Reserve.

Ocheltree discovered many other advantages in his first collaborative research trip to China. Outside of experimenting with new scientific techniques, he also presented his own research on plant water-use strategies and plant phenology, and visited the local countryside. Seeing the similarities and differences in climate, landscape, species and research approaches provided him with a fresh perspective.

“Interacting with other scientists that have such different backgrounds exposes me to new ideas that I can bring back and incorporate into work in my lab, department and CSU.” he said.

With a new outlook on how plants recover from drought, Ocheltree is ready to explore new research questions and hypotheses that reveal how plants may adapt to more extreme climate conditions.