Antioxidant enzymes change in relation to superficial scald development in pear fruit during cold storage
Superficial scald is a physiological disorder of apple and pear fruits associated with preharvest factors, postharvest treatment and genetic traits of each cultivar. In the Po Valley, two pear cultivars (Abbé Fétel and Doyenne du Comice) and two advanced selections (CREA 171, CREA 264), obtained by CREA Centro di Ricerca Olivicoltura, Frutticoltura e Agrumicoltura (Forlì, Italy) pear breeding program, picked in August-September, were stored at -1°C and 95% RH until January. In this study, the antioxidant enzymatic system of four cultivars/selections was evaluated during storage to investigate differences in scald susceptibility. In pear peel, superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (POD), polyphenol oxidase (PPO), and lipoxygenase (LOX) were evaluated. Significant differences in scald incidence were observed both in pear cultivars and selections. Abbé Fétel and CREA 171 showed lower superficial scald susceptibility compared to Doyenne du Comice and CREA 264, after being cold stored for five months. In fruit peel, SOD and CAT activities were higher in scald-resistant than in scald-susceptible pear cultivars and selections. However, APX activity in peel was very similar in all tested pear fruits. Superficial scald induced an increase in PPO and POD activities involved in fruit-browning during cold storage. Furthermore, an increase in LOX activity due to deoxygenation of polyunsaturated fatty acids producing toxic hydroperoxy fatty acids and consequent membrane damage in fruit peel was observed. This study shows that some pear cultivars and selections have different superficial scald susceptibility enabling them to induce activities of several antioxidant enzymes following cold storage. Regulation of antioxidant enzymes alleviates oxidative damage and in addition to other biochemical features could be involved in determining the susceptibility/resistance to superficial scald development of pear fruit.
Petriccione, M., Caracciolo, G., Zampella, L., Mastrobuoni, F. and Baruzzi, G. (2021). Antioxidant enzymes change in relation to superficial scald development in pear fruit during cold storage. Acta Hortic. 1303, 485-492
oxidative stress, physiological disorder, pear cultivars and advanced selections