Plants growing close together can warn each other about incoming stress, helping nearby plants survive damaging conditions.
In experiments with thale cress (Arabidopsis thaliana), plants were grown either alone or packed closely together. When exposed to intense light, isolated plants suffered severe damage, while crowded plants coped far better.
Within an hour, closely grown plants activated more than 2,000 genes linked to protection against multiple stresses. Isolated plants showed little defensive gene activity.
Researchers found that crowded plants released hydrogen peroxide, a chemical signal that passed between neighbouring plants. This molecule alerted nearby plants to prepare their defences, marking the first evidence that hydrogen peroxide can act as a stress warning signal between plants.
