Foliar application of putrescine before a short‐term heat stress improves the quality of melon fruits (Cucumis melo L.)

Abstract BACKGROUND Climate change has caused an increase in the frequency and intensity of heatwaves, worldwide, which subject plants to thermal stress for short periods; this can affect the quality of melon fruits, both negatively and positively. Since the application of putrescine has been shown to help increase tolerance of abiotic stresses, the objective of this work is to determine the effects of the foliar application of putrescine (1.5 and 5 mmol L ‐1 ) before a short heat stress (HS) on the quality of melon fruits. RESULTS The results indicate that HS had a positive effect on the quality of melon fruits, since it increased the total sugars and polyamines contents and the antioxidant capacity, and reduced the presence of substances undesirable in foods such as nitrate. However, the fruit quality was further increased by the combination of HS and putrescine (5 mmol L ‐1 ). In this case, the melon fruits showed increases in their antioxidant capacity and contents of polyamines, amino acids and minerals beneficial to health. The nitrate concentration was even lower than in the control fruits. CONCLUSION This novel study highlights the possibility of improving the nutritional quality of melon pulp by applying foliar putrescine in combination with a short period of high temperature. © 2020 Society of Chemical Industry