Freezing injury is an important limiting factor in the production of pomegranate in Iran.The aim of the present study was to evaluate the effect of Paclobutrazol on cold hardiness of pomegranate cv. ‘Malas Saveh’. Different concentrations of PBZ including: 0 (control), 125, 250, 500 or 1000 mg l-1 were sprayed on one-year-old plants in August and electrolyte leakage of their stems was measured at three acclimation stages (November, January and March). PBZ treatments, especially at 500 and 1000 mg l-1 concentrations, increased cold hardiness and corresponding soluble carbohydrate and proline contents. The highest variation in freezing tolerance was observed between control and PBZ treated plants in January, and the lowest found in November. Irrespective of PBZ treatment, correlations between cold hardiness and soluble carbohydrate concentrations were stronger, compared to proline. Soluble carbohydrate was highest in January, associated with deep dormancy, whereas the maximum proline content detected in March, deacclimation stage. Results suggest that PBZ application can reduce low temperature-induced dysfunction of cell membrane through increasing soluble carbohydrate and proline contents.
