Abstract: Adverse environmental stresses have bad effects on growth of plant, so it is very important to study improving alfalfa for tolerance to abiotic stesses. Cultivated alfalfa(Medicago sativa L.), perennial legume crop, is wildly planted in the world and is one of the most frequently studied species. The development of plant gene engineering creates an important approach for alfalfa stress-resistant breeding. In this research, to increase superoxide-scavenging capacity and thereby to improve stresses ...