Plants that grow close together can alert their neighbours to danger, helping them survive environmental stress. In experiments with thale cress (Arabidopsis thaliana), researchers compared plants grown alone with those grown in dense clusters where leaves touched. When exposed to intense light, isolated plants suffered severe damage, while crowded plants coped far better.
Within an hour of stress exposure, closely packed plants activated more than 2,000 genes linked to protection against multiple stresses. Isolated plants showed little change in gene activity. The findings indicate that signals pass between neighbouring plants, allowing them to prepare defences in advance.
The study identified hydrogen peroxide as the key messenger. While this chemical is already known to trigger defence responses within plants, this research provides the first evidence that it can move from one plant to another, acting as an early warning system against stress.
