Effect of Arginine Treatment on Disease Resistance to Alternaria Rot of Postharvest Winter Jujube

In order to study the effect of arginine (Arg) treatment on disease resistance of postharvest winter jujube fruit, the fruits were soaked in Arg solutions at different concentrations (0, 20, 200, 1000 μmol/L), then Alternariaalternata challenge inoculation was performed on the treated jujube fruits, and later the lesion diameter, the activities of resistance-related enzymes and the contents of flavones, polyphenols and lignin were determined. The results showed that Arg treatment significantly slowed down the expansion of the lesion diameter in the jujube fruitsinoculated with A.alternata. Further studies showed that Arg treatment induced the increase of the activities of phenylalamine ammonialyase (PAL), peroxidase (POD), β-1,3-glucanase (GLU) and chitinase (CHI), among which Arg treatment at 200 μmol/L was the most active concentration. At the same time, Arg treatment increased the contents of flavones, polyphenols and lignin in winter jujube, and the contents of flavones, polyphenols and lignin in the fruits treated by 200 μmol/L Arg were the highest. Therefore, Arg treatment enhanced the disease resistance of postharvest winter jujube fruits by increasing the activities of disease-resistant enzymes (PAL, POD, GLU, CHI) and the contents of flavones, polyphenols and lignin,and it can be a promising alternative that will be used in the preservation of postharvest winter jujube.