How a humble plant may help us save crops from drought

Plants suffer greatly during summer droughts, which can lead to billions of dollars in lost crops, and a higher demand for irrigation. This can cause a decline in productivity, resulting in food shortages and rising prices. It’s a familiar story – but one that might soon change.

Researchers from Colorado State University, the University of Colorado, and the U.S. Department of Agriculture have shown conclusively that plants can help themselves recover from severe drought, without outside intervention.

This process, called “refilling,” has been debated by plant scientists for years. But the new research demonstrates that it can happen naturally in plants.

The science behind plant recovery

When plants dry out, they suffer damage deep inside. Their water transport system, known as the xylem, becomes blocked by gas bubbles. These bubbles, called embolisms, prevent water from flowing.

In many plants, recovery is difficult of even impossible once embolisms have formed. Scientists have long debated whether plants can clear these blockages on their own. Some experiments suggested they could, but the methods used raised doubts.

Traditional studies often involved cutting plants and forcing water back into the tissues under unnatural pressures. Critics pointed out that this could create “artifacts” – results that didn’t reflect what happens in nature.

Observing plant recovery in real-time

To settle the debate, the CSU, CU, and USDA team took a different approach. They used a micro-CT scanner, an advanced type of X-ray machine, to watch the plants without harming them. This machine allowed the researchers to observe internal plant processes as they unfolded in real time.

What they found was striking. Within 24 hours of watering, a type of wild grass that had become dehydrated showed a complete reversal of embolism. Its water transport system – initially almost entirely blocked – returned to full function.

“This is the first convincing evidence of the reversal, or refilling, of embolism in a vascular plant species, with the plant regaining full functional recovery afterward,” said Sean Gleason, a researcher with the USDA Agricultural Research Service, and a CSU affiliate.

What this means for crops

The implications are significant. If scientists can understand the genetic mechanisms behind refilling, they might be able to breed crops that can survive droughts more effectively.

The team has already started looking for other plants with this trait. The hope is to identify the genetic triggers that make refilling possible. Once found, these traits could be introduced into agricultural crops.

“If a plant can recover from drought quickly by refilling, then you might be able to recoup some losses during a drought year,” said Troy Ocheltree, a CSU associate professor in the Warner College of Natural Resources.

“If plants can refill, this may allow flexibility in the amount and timing of irrigation, although additional work is required to identify how refilling would impact crop water use.”

A resilient plant hiding in plain sight

The plant that proved the theory wasn’t found in a lush field or a greenhouse. It was discovered growing in a parking lot, thriving in the cracks of hot, dry asphalt.

The research team, including lead author Jared Stewart and graduate students Brendan Allen and Stephanie Polutchko, picked this grass because of its resilience.

After a prolonged drought, the grass appeared dead and had up to 88% of its xylem blocked. But once watered, its vascular system bounced back overnight.

So far, this wild grass is the only species known to refill naturally. However, the researchers believe others might exist.

“We don’t know how common this is,” Ocheltree said. “But the fact that we found a plant in the parking lot that refills makes me think there’s probably others out there that also refill. It shifts our mindset.”

The equipment behind the discovery

A key part of the study’s success was access to a micro-CT scanner from CSU’s College of Veterinary Medicine and Biomedical Sciences.

This specialized machine, which is typically used for small animals, emits lower radiation levels than standard CT scanners. It allowed the researchers to scan the plants repeatedly without causing harm.

Support from the lab’s staff was essential. Professor Nicole Ehrhart, director of CSU’s Center for Healthy Aging, and lab technician Laura Chubb played critical roles. Chubb initially scanned the plants and later trained Gleason to operate the machine.

“The resilience of this humble grass – reviving its vascular system overnight – was both surprising and deeply compelling,” Ehrhart said.

“Collaborations like this remind us how powerful it can be when tools developed for biomedical research are applied in new ways to answer fundamental questions about life. We were thrilled to contribute to such impactful science.”

Breeding plants to resist drought

The discovery opens the door to exciting possibilities. With further research, scientists might find more species capable of refilling.

Experts can work toward breeding these drought-resistant traits into crops – a step that could improve food security and help farmers adapt to a changing climate.

For now, a scrappy little grass from a parking lot is showing the world that recovery from drought isn’t just possible – it’s real.

The full study was published in the Proceedings of the National Academy of Sciences.

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