Plants growing close together can alert one another to environmental stress, improving their chances of survival under harsh conditions.
In experiments with thale cress (Arabidopsis thaliana), researchers compared plants grown alone with those 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 stress protection, whereas isolated plants showed little change in gene activity.
The findings suggest that stressed plants send warning signals to nearby neighbours. The study identified hydrogen peroxide as the key messenger, released by crowded plants and shared between them. This is the first evidence that hydrogen peroxide can pass from one plant to another, allowing neighbouring plants to prepare their defences before damage occurs.
