Putrescine treatment increases the antioxidant response and carbohydrate content in zucchini fruit stored at low temperature

Zucchini fruit are marketed at an immature stage. Its subtropical origin makes zucchini fruit susceptible to chilling disorders when stored at low non-freezing temperatures. In this study, we have investigated the implication of treatment with putrescine (1 mM), that improves cold storage resistance, on the antioxidant mechanisms and carbohydrate content, and its correlation with the mechanisms that alleviate cold stress in zucchini fruit. Fruit treated with putrescine exhibited higher ascorbate peroxidase, catalase and glutathione reductase activities, and contained higher amounts of ascorbate, FRAP, glucose, fructose and raffinose than control fruit during cold storage. Furthermore, the treatment with putrescine reduced lipoxygenase activity. Our results show that a putrescine treatment, that alleviates chilling injury, also modulates antioxidant system and carbohydrate content in zucchini fruit under cold stress. This response could be due to the degradation of putrescine, and the induction of the gamma-aminobutyric acid (GABA) shunt pathway. (C) 2016 Elsevier B.V. All rights reserved.