Chilling Resistance in Pomegranate Fruits with Spermidine and Calcium Chloride Treatments

Pomegranate fruits were treated with 2% calcium chloride in combination with 2 mM of spermidine by either normal dip or vacuum infiltration for 4 min and then stored at 2 degrees C for 4 months. After 0, 30, 60, 90, and 120 days, 12 fruits were taken from each treatment and stored at 20 degrees C for an additional 3 days. Compared with control fruits, significantly higher activities in catalase and superoxide dismutase and a lower activity in peroxidase were noted in treated fruits. It was found that antioxidant enzymes are responsible for inducing chilling tolerance in pomegranate fruits and spermidine in combination with calcium chloride can improve these enzymatic activities.