Effects of Exogenous Salicylic Acid on Growth and Antioxidant Enzyme Activities of Tea Plant (Camellia sinensis) under Salt Stress

Tea cultivar,‘Longjingchangye',was used to study the effects of different concentrations exogenous salicylic acid(0,0.5,1.0,1.5mmol·L-1)on growth and antioxidant enzyme activities of tea plant(Camellia sinensis)under 40mmol·L-1 NaCl stress with foliar spray.The aim is to explore effects of salicylic acid on tea salt tolerance.The results indicated that exogenous salicylic acid significantly increased fresh mass and dry mass of tea leaves and all plant,enhanced activities of protective enzymes,such as superoxide dismutase(SOD),peroxidase(POD),and ascorbate peroxidase(APX),but inhibited activity of catalase(CAT),and increased the content of ascorbic acid(AsA)and glutathione(GSH),and decreased malondialdehyde(MDA)content and electrolyte leakage,decreased the content of O2-and H2O2.The optimum treatment concentration was 1.0mmol·L-1.Salicylic acid could be considered as an exogenous hormone to improve osmotic regulation and antioxidation,water balance,scavenging reactive oxygen species(ROS)and membrane stability,alleviating the harmfulness of salt stress,promoting tea plant growth and enhancing salt resistance of tea.