Role of Nitric Oxide and Calcium Signaling in Oxalate-induced Resistance of Cucumber Leaves to Pseudoperonospora cubensis CHANGES OF THE LEVEL OF Ca2+ IN CELLS OF LO-QUAT LEAFLETS UNDER LOW TEMPERATURE STRESS ADVANCES IN RESEARCHES ON MOLECULAR BIOLOGY OF PLANT COLD RESISTANCE Regulation of Exogenous Ethylene on Ca2+- ATPase Activity and Lipid Peroxidation of Microsomal Membrane in Strawberry Fruit Regulation of Exogenous Ethylene on Ca2+- ATPase Activity and Lipid Peroxidation of Microsomal Membrane in Strawberry Fruit Changes of the Level of Ca2+ in Cells of Rice Seedlings Under Low Temperature Stress