A STUDY ON THE EFFECTS OF THE BEST COMBINATION OF COPPER, ZINC, IRON, AND MANGANESE ON THE RELATIONSHIP OF LETTUCE RESISTANCE TO BOTRYTIS CINEREA AND ITS ANTIOXIDANT SYSTEM
The aim of this study was to reveal the mechanisms and mutual relationships of the lettuce resistance to Botrytis cinerea under the different combinations treatments of copper, zinc, iron, and manganese compounds. The results of this research confirmed: The copper sulfate 0.16 mg/L, zinc sulfate 0.22 mg/L, EDTA-iron 60 mg/L, and manganese sulfate 3.20 mg/L, were added to a Yamasaki nutrient solution, which lead to the antioxidant capacity of the lettuce leaves became stronger. Following the inoculated-pathogen treatment, the contents of superoxide anion radical (O2.-), Hydrogen peroxide (H2O2), and malondialdehyde (MDA) in the lettuce leaves were decreased. The superoxide dismutase (SOD) played a dominant role in eliminating the influence of O2.-. The elimination of the H2O2 , and the maintenance of a certain level was the combined effect of the catalase (CAT), ascorbate peroxidase (APX), and glutathione peroxidase (GPX), the CAT was the dominant enzyme, the APX and CAT enzymes showed a synergic action, and the GPX and CAT enzymes were complementary. The copper, zinc, iron, and manganese were found to have affected the mechanism of this reaction. Therefore, it was a feasible approach to add the correct amount of metal elements into the Yamasaki nutrient solution, which would potentially improve the resistance of the lettuce to Botrytis cinerea and activate its antioxidant enzymes.