Investigation of physiological and biochemical responses of two strawberry cultivars to cold stress

The aim of this study was to investigate the importance of some physiological and biochemical properties related to cold adaptation mechanisms.We aimed to adopt properand efficient indices for identification of winter cold tolerance and susceptibilityin two strawberry cultivars. Differentphysiological and biochemical traits were studied under different cold treatments on the leaf and crown tissues of two strawberry cultivars of Selva and Queen Elisa. Plants prepared from new runners after being planted in the pot and grown until late November. Potted plantswere kept in out doorcondition to gradually adapt to low temperature. After plant adaptation, coldtreatments were artificially applied with adjustable chilling apparatus. The samples were kept under the final cold treatment for three hours and then removed from the apparatus and transferred to the laboratory for measurement of different traits. Factorial experiment was conducted in a completely randomized design. The results showed that the levels of oxidative enzymes including superoxide dismutase, guaiacol peroxidase and catalase were significantly affected by cultivar, texture and temperature changes. Also, with decrease in temperature, the ion leakage rate, proline, protein, hydrogen peroxide, membrane lipid and carbohydrate peroxidation increased and these values were generally higher in Queen Elisa cultivar than in Selva. Increasing levels of these factors were more evident in the process of lowering temperature in the crown tissue. The leaf relative water content also decreased with decreasing temperature, which overall confirms the tolerance to cold Queen Elisa cultivar.