Plants growing close together can warn one another about environmental stress, helping neighbouring plants survive damaging conditions.
In experiments with thale cress (Arabidopsis thaliana), scientists grew plants either alone or tightly packed so their leaves touched. When exposed to intense light, isolated plants suffered severe damage, while crowded plants coped much better. Within one hour, closely grown plants activated more than 2,000 genes linked to stress protection, whereas isolated plants showed little defensive response.
The findings suggest that plants transmit warning signals to nearby neighbours. Researchers identified hydrogen peroxide as the key messenger, released by stressed plants and received by others nearby. While hydrogen peroxide is known to trigger defence responses within plants, this study provides the first evidence that it can pass between plants, allowing groups to prepare collectively for incoming stress.
