The effect of cold temperature stress on antifreeze protein production and lipid peroxidation in two citrus species

Quality wise, most citrus species from North of Iran are appreciated by the Iranian peaple. They, therefore, deserve commercial and research value. To protect their cells and tissues from oxidative damage, most plants produce metabolites such as carbohydrates, amino acids, anti-freeze protein and antioxidants. Determination of lipid peroxidation, and detection of anti-freeze protein were used to explore the mechanism by which a plant could resist to cold stress. In this research, two species of citrus family, citrange (Citrus sinensis) and bitter orange (Citrus sinensis x Poncirus trifoliata) were subjected to a range of temperature. Results showed that a protein with molecular weight of 23 KD was produced in both citrus species at temperature below zero degree. On the other hand, lipid peroxidation in both species increased only slightly in response to cold stresses below 0°C.