Investigating The Effect of Postharvest Application of Putrescine and Spermidine on Preserving Quantitative and Qualitative Properties of Grape Cv. Shahroudi

Grape is one of the most important and ancient fruits in the world that have been used by humans. the aim of this study was to investigate the effect of post-harvest application of putrescine and spermidine polyamines on maintaining the quantitative and qualitative characteristics of ‘Shahroudi’ grapes during storage. Factorial experiment with two polyamine factors including two types of polyamines, putrescine and spermidine, each in 3 concentrations (0.5, 1 and 2 mmol) and storage time (0, 15, 30, 45, 60, 75, 90 and 105 days) based on a completely randomized design in 2019. After treatment, the fruits were stored for 105 days at a temperature of 2 ° C and a relative humidity of 85-95% and their quantitative and qualitative characteristics were evaluated during storage. The results showed that the treatments had a significant effect on fruit firmness, weight loss, anthocyanin content, titratable acidity, vitamin C and total soluble solids at the level of 1% probability and on pH at the level of 5% probability, but on the percentage of fruit juice It had no significant effect. Also, the effect of storage time on all traits was significant at the 1% probability level. However, the interaction effects of treatment and storage time showed a significant effect on total phenol, acidity and Total soluble solids at 1% probability level and a significant effect on pH at 5% probability level. In conclusion, considering maintain different properties using putrescine and spermidine during storage and delaying in senescence and increasing storage life of fruits of ‘Shahroudi’ grape, polyamines application as a postharvest treatment recommended.