defense activity
2.Activities of defense enzymes including peroxidase (POD), phenylalanine ammonia-lyase (PAL), chitinase (GHT) and β-1,3-glucanase (GLU) significantly increased, and activities of antioxidant enzymes such as catalase (CAT) and ascorbic peroxidase (APX) decreased but glutathion reductase (GR) activity increased, and H2O2 accumulated in young Yali pears sprayed with SA or ASM.

