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Scientists at the University of Helsinki discovered how plants heal their protective outer layer, the periderm. The diffusion of ethylene and oxygen through a wound triggers repair—a finding with potential implications for crop resilience and food preservation.

All living organisms rely on protective barrier tissues to shield them from the environment. In plants, the periderm which forms the tough outer cork layer plays this role, helping to prevent water loss and block harmful microbes, for example in potato skin and tree bark. But what happens when this protective layer is damaged? A new study from the University of Helsinki, in the journal Nature, used the model plant Arabidopsis thaliana and revealed that plants rely on gas diffusion as a signal to detect injuries and kick-start regeneration.

The research team led by Professor Ari Pekka Mähönen from the Faculty of Biological and Environmental Sciences found that an intact periderm is nearly impermeable to gases, causing ethylene gas, a plant hormone, to build up inside plant tissues while oxygen is depleted because of normal growth.

When the periderm is wounded, however, the dynamics shift: ethylene escapes and oxygen enters through the injury site. These changes act as warning signals that trigger the plant to begin regenerating the periderm.

Once the new barrier is completed, gas diffusion is again restricted. This results in ethylene accumulation and oxygen depletion, signaling that regeneration can stop and normal growth can resume.

"We initially discovered the role of ethylene in regeneration. Then, in collaboration with University of Oxford Professor Francesco Licausi, a leading expert in oxygen sensing in plants, we also identified oxygen. This discovery reveals a beautifully simple, yet effective strategy plants use to monitor damage," Dr. Hiroyuki Iida, the lead scientist of this project in the Mähönen group, explains.

"Gas diffusion through a wound isn't just a consequence of injury—it's the signal that initiates healing," Iida continues.

Better resilience for important crops and longer shelf life for vegetables

The findings have far-reaching implications. Understanding how periderm regeneration is triggered can help improve the resilience of crops like potatoes, carrots, and fruits. Damaged barriers can lead to moisture loss, vulnerability to disease, and ultimately spoilage of vegetables or fruits. By enhancing the plant's natural repair system, scientists could improve crop survival, reduce post-harvest food waste, and help plants better withstand environmental stresses such as drought.

As global food systems face growing pressure from climate change and population growth, this research offers promising new avenues for boosting agricultural sustainability.

"Improving the healing capacity of barrier tissues could be a game-changer for food storage and plant resilience," Mähönen concludes.