Dear Editor,Hydrogen sulfide (H2S),a colorless gas with a foul odor,has been known for hundreds of years as a toxic environmental pollutant.Recently,H2S has been recognized as the third gasotransmitter after nitric oxide and carbon monoxide,with similar biological functions.The endogenous production of H2S and its physiological functions have been initially revealed in mammalian systems,which are mediated by various molecular targets including different ion channels and signaling proteins.Similarly,H2S can be produced enzymatically in plants.H2S has been reported to have multiple functions in alleviating abiotic stresses such as improving plant tolerance to drought,salt,and heat.It has also been shown to improve plant resistance to heavy metal stresses.