Influences of Brassinosteroide and Hot Water on Postharvest Enzyme Activity and Lipid Peroxidaion of Lime (Citrus aurantifolia L.) Fruit During Storage at Cold Temperature

Storage of Lime (Citrus aurantifolia L.) fruits, originally a tropical fruits, in low temperature confronts with several difficulties  due to the risk of chilling injury (CI). To develop an effective method aiming to  reduce CI, the effects of treatments containing 0, 0.5 and 1 Mg/lit brassinosteroids (BRs) and hot water (HW) including 20°C as control, 45 and 55°C for 30 minute on CI was studied. Moreover lipid peroxidaion, hydrogen peroxide, catalase (CAT) and peroxidase (POD) activities were investigated in lime fruits stored at 1°C for 21 days. The CI, lipid peroxidaion, hydrogen peroxide were significantly reduced by BRs treatment particularly at 1Mg/lit and 45°CHW treatment. Furthermore fruits treated with 1Mg/lit BRs and 45 °C HW treatment exhibited significantly higher CAT and POD activities in comparison with the control fruits. These results suggest that BRs and HW treatment protect lime fruits from CI by enhancing antioxidant enzymes such as POD and CAT activities, and reduce lipid peroxidaion, hydrogen peroxide contents, and maintaining membrane integrity.