New "Stomata in-sight" system allows scientists to watch plants breathe in real-time

URBANA, Ill. — For centuries, scientists have known that plants "breathe" through microscopic pores on their leaves called stomata. These tiny valves are the gatekeepers that balance the intake of carbon dioxide into the leaf for photosynthesis against the loss of water vapor from the leaf to the atmosphere. Now, researchers at the University of Illinois Urbana-Champaign have developed a groundbreaking new tool that allows them to watch and quantify this process in real-time and under strictly controlled environmental conditions.
The study, published in the journal Plant Physiology, introduces a system dubbed "Stomata In-Sight." It solves a long-standing technical challenge in plant biology: how to observe the microscopic movements of stomatal pores while simultaneously measuring how much gas they are exchanging with the atmosphere.
The "Mouths" of the Plant, stomata (Greek for "mouths"), are critical to global agriculture. When they open, plants get the carbon they need to grow, but they also lose water. Therefore, understanding how the number and operation of these pores determine the efficiency of photosynthetic gas exchange is key to developing crops that need less water to grow and can reliably produce food, biofuel and bioproducts in times and places of drought stress.
"Traditionally, we've had to choose between seeing the stomata or measuring their function," explained the research team. Previous methods often involved making impressions of leaves (like taking a dental mold), which only captures a static snapshot, or using standard microscopes that observe the leaf without being able to control the conditions the leaf is experiencing. This is important because the stomata are highly responsive to variation in almost all aspects of the environment.
A Window into the Leaf The new "Stomata In-Sight" system integrates three complex technologies into one:
1.    Live Confocal Microscopy: A powerful imaging technique that uses lasers to create detailed, three-dimensional views of living cells without slicing into the plant.
2.    Leaf Gas Exchange: High-precision sensors that measure exactly how much CO2 the leaf is taking in and how much water it is releasing.
3.    Environmental Control: A chamber that allows researchers to manipulate light, temperature, humidity, and carbon dioxide levels to mimic real-world conditions.
By combining these, the team can watch exactly how the stomata respond to variation in the environment.
Why It Matters This high-definition view of plant physiology could revolutionize how we breed crops. By understanding the precise mechanical and chemical signals that cause stomata to open or close, and how that is influenced by the number of stomata on a leaf, scientists can identify genetic traits that lead to "smarter" plants—crops that use water most efficiently. That is crucial because water is the environmental factor that limits agricultural production the most.
The system was developed by Joseph D. Crawford, Dustin Mayfield-Jones, Glenn A. Fried, Nicolas Hernandez, and Andrew D.B. Leakey at the Department of Plant Biology and the Institute for Genomic Biology at the University of Illinois.
About the Paper The work was supported by the U.S. Department of Energy's Center for Advanced Bioenergy and Bioproducts Innovation, the National Science Foundation, and a philanthropic gift, and is published as an open-access article titled, "Stomata In-Sight: Integrating Live Confocal Microscopy with Leaf Gas Exchange and Environmental Control," in Plant Physiology. https://doi.org/10.1093/plphys/kiaf600
Contact: Andrew Leakey, leakey@illlinois.edu