The mitogen-activated protein kinase (MPK) cascades are well known as highly conserved signaling transduction pathways found in all eukaryotes,which regulate numerous processes in plants,including biotic and abiotic stress responses and developmental programs.Hydrogen peroxide (H₂O₂) and nitric oxide (NO) acting as important signaling molecules also mediate a wide array of responses to developmental cues and environmental stresses in plants.Recently,many studies have revealed a much more complex relationship between MPK cascades and signaling molecular H₂O₂ or NO.On the one hand,MPK signaling pathways are not only induced by H₂O₂ or NO but can also regulate the production or scavenging of H₂O₂ or NO in some signal transduction pathways of many stimulating factors,on the other hand,MPK cascades and H₂O₂ or NO signaling are functional respectively in different signal pathways stimulated by a same factor.In this paper,the recent progress on the interrelationship between MPK cascades and H₂O₂ or NO signaling is reviewed and discussed.Finally,the problems remained in this field are analyzed.