AVOIDING THE PALENESS OF POMEGRANATE ARILS BY PREHARVEST APPLICATION OF SALICYLIC ACID AND POTASSIUM SULFATE

The physiological disorder of aril paleness, thought to occur due to oxidative stress, in pomegranate threatens the popularity of this fruit. Based on the results of a preliminary experiment on pomegranate trees, a factorial experiment was designed consisting of salicylic acid (0, 0.3 and 0.6 mM) and potassium sulfate (0, 0.5 and 1%). The prepared concentrations of above mentioned treatments were foliar sprayed to the trees 9 and 13 weeks after full bloom. Results showed that these compounds could alleviate the aril paleness of fruit, manifested by higher chroma values of arils and peel of pomegranate and maintain the overall quality of fruit compared to the control. In addition, total phenolics and antioxidant activity increased in fruit of treated tree by potassium sulfate at harvest while the lowest values of these parameters were observed in the control. The result of measuring photosynthetic parameters and pigments showed that treated plants have higher Fv/Fm, pi and some pigment of plants compared to the control. Thus preharvest treatments with salicylic acid and potassium sulfate could be considered as suitable tools to avoid paleness of pomegranate arils with higher bioactive compounds and antioxidant activity as compared to control fruit.