Abstract: Plant releases a variety of volatile substances into the environment when they suffered from insect feeding, wound or abiotic stress, to help plant combat the damage directly or indirectly. These volatile substances can also provide a precaution for the nearby plants to cope with the incoming threat. H₂S has been reported as an intracellular gasotransmitter which can increase the tolerance of plant to multiple stresses. We explored the possibility of H₂S to be a plant-to-plant signaling molecule in multiple plants. The H₂S concentrations in air increased when the foxtail millet, Chinese cabbage, tomato or Arabidopsis seedlings were treated with 40% PEG 8000. When the Arabidopsis or the foxtail millet was treated with PEG 8000, the H₂S content and the expression levels of the H₂S response genes in the neighboring non-stressed plants were increased, and the stomatal closure of these plant was also induced. However, when the lcd/des1 was treated with PEG 8000, not a similar phenomenon could be observed in the neighboring plants of this mutant. Therefore, H₂S not only functions as an intracellular signal molecule, but also serves as an information transfer molecule between plant individuals, that is, by releasing H₂S into the surrounding environment, plants under stress can provide early warning information of stress to their neighboring plants, which may be of great significance to the survival of the population.

Key words: hydrogen sulphide, volatiles, plant communication, stress