Cloning and Expression Analysis of 14-3-3 Protein Gene of Spinach under Nitrate Stress Effect of Exogenous Melatonin on the Antioxidant System of Cucumber Seedlings Under Nitrate Stress Effect of Exogenous Melatonin on the Antioxidant System of Cucumber Seedlings Under Nitrate Stress Effects of Cerium Sulfate Foliar Spray on Antioxidant Activities and Photosynthesis of Tomato Seedling Leaves under Calcium Nitrate Stress Growth and Physiological Responses of Cherry Tomato Seedlings under Nitrate Stress