Induction of Disease Resistance and Phenylpropanoid Metabolism in Apricot Fruits by Pre-Harvest Salicylic Acid Treatment

Xinjiang apricot fruits(‘Saimaiti' cultivar) were sprayed with 1.0 mmol/L salicylic acid at four growth periods: setting, enlargement, color-turning and 48 h before picking. The post-harvest apricot fruits were stored at 4 ℃, 90%–95%relative humidity(RH). The lesion diameter and the incidence of disease of apricot fruits inoculated with Alternaria alternata, the activities of phenylalanine ammonia-lyase(PAL), Co A ligase(4-CL) and cinnamate-4hydroxylase(C4H) and the contents of flavanoids, lignin and total phenolics in apricot fruits were measured regularly. The effect of salicylic acid on phenylpropanoid metabolism in apricot fruits during storage period was studied. The results showed that the lesion diameter and disease incidence of apricot fruits during storage were significantly inhibited by pre-harvest salicylic acid treatment. Besides, the activities of PAL, C4 H and 4-CL and the contents of flavonoids, lignin and total phenolics in apricot fruits were increased.