Antioxidant enzymes and fatty acid composition as related to disease resistance in postharvest loquat fruit

Two cultivars of loquat fruit were stored at 20 °C for 10 days to investigate the relationship between disease resistance, and fatty acid composition and activities of endogenous antioxidant enzymes. The results showed that decay incidence increased with storage time in both cultivars. A significantly lower disease incidence was observed in 'Qingzhong' fruit than in 'Fuyang', suggesting 'Qingzhong' had increased disease resistance. Meanwhile, 'Qingzhong' fruit also had lower levels of superoxide radical and hydrogen peroxide, and lower lipoxygenase activity, but higher levels of linolenic and linoleic acids and higher activities of catalase (CAT) and ascorbate peroxidase (APX) compared with 'Fuyang'. These results suggest that the higher levels of linolenic and linoleic acids and the higher activity of CAT and APX have a role in disease resistance of postharvest loquat fruit.