Effects Of Uv-c Radiation On Disease Resistance And Commodity Quality In Harvested Apple

In this study, ‘Red Fuji’ apple was used as the experimental material. Apples were treated with different doses of short-wave ultraviolet(UV-C), followed by inoculated with extended Penicillium, to explore the optimal radiation dose of this study. The research of the effect of UV-C on apple disease resistance under different temperature was conducted through inoculation with Pencillium expansum and Botrytis cinerea after radiation with optimal dose under room temperature(20℃) and low temperature(0℃).The effect of radiation with UV-C on physiology metabolism and storage quality of postharvest apples was researched. In the meantime, the possible mechanism of UV-C treatment which improve disease resistance, delay aging and enhance storability of post-harvest apple was studied. The main results of this study were listed as follows:1. Different doses of UV-C treatment can inhibit the occurrence and expansion of Penicillium, and the incidence and the decay diameter of each treatment group were significantly lower than control of those. But the inhibition effect was not continues to increase with increasing dose of UV-C. The effect of 7.5kJ/m2 dose was better than the other doses(2.5, 5.0, 10.0, 12.5kJ/m2), so the optimal dose of UV-C was 7.5kJ/m2 in this experiment.2. Dose of 7.5kJ/m2 UV-C can significantly reduce the disease incidence of Penicillium and inhibit the expansion of decay diameter at low temperature. The decay diameter of apple treated with UV-C was 39.93 mm, which was apparently lower than control of that(55.37mm). Dose of 7.5kJ/m2 UV-C can also inhibit decay index and decay diameter of Botrytis at room temperature and low temperature.3. Whether at room temperature or under low temperature storage conditions, short wave ultraviolet can effectively decrease the weight loss, inhibit respiration rate, delay decreasing of fruit firmness, soluble solids content and titratable acid content, delay senescence, better maintain fruit quality and prolong storage period.4. UV-C treatment can induce activity of superoxide dismutase and peroxidase in harvest apples increased, inhibit the accumulation of MDA content, then protect the integrity of cell membranes; enhance activities of phenylalanine ammonia lyase and polyphenol oxidase activity, improve the content of total phenolic, to increase disease resistance and apple fruit storability and maintain fruit quality.