Effects of exogenous GABA on reactive oxygen species metabolism and chlorophyll fluorescence parameters in tomato seedlings under NaCl stress

The paper investigated the effects of exogenous GABA application to salinized nutrient solution on reactive oxygen species(ROS) metabolism and chlorophyll fluorescence parameters in the seedlings of one tomato cultivar 'Jin Peng No.1' under NaCl stress.The results showed that seedlings grown in nutrient solution salinized with NaCl increased O·-2productive rate,MDA content and antioxidant enzyme(SOD,CAT) activities,but the increasing range of antioxidant enzyme activities was lower than ROS productive rate,which lead to decreased capability of photosystem in tomato seedlings.Exogenous GABA application treatments relieved the harm of NaCl stress to seedlings growth,meanwhile O·-2 productive rate and MDA content in leaves and roots with were significantly lower than NaCl treatment.Compared with NaCl treatment,the activities of SOD,POD,CAT and Fv/Fm,ΦPSII,qP were significantly increased,but NPQ was obviously decreased with GABA application.The findings suggested that exogenous GABA application played an important role for enhancing salt tolerance in tomato seedlings.