Reactive Oxygen Species Homeostasis and Carbohydrate Metabolism Involved in Wound Healing of Carrot Induced by Hot Water Treatment

Although the information on regulation of reactive oxygen species (ROS) homeostasis or carbohydrate metabolism has been published in other wounding-responsive horticultural crops, the involvement of that in carrot remains unknown, especially treatment with hot water. In this study, ROS and carbohydrate metabolism analysis during wound healing was performed to clarify the underlying mechanism for the wounded carrots subjected to hot water treatment. Results showed that 45 degrees C hot water promoted NADPH oxidase (NOX) and superoxide dismutase (SOD) activities in healing carrots, elevated O-2(center dot-) and H2O2 contents. Also, hot water enhanced catalase (CAT) and peroxidase (POD) activities, the activities of AsA-GSH cycle-related as well as the ascorbic acid and glutathione levels. Additionally, hot water stimulated acid invertase (AI) and neutral invertase (NI) activities with a higher level of sucrose, fructose and glucose, triggered stronger activities of hexokinase (HK), phosphofruc tokinase (PFK), pyruvate kinase (PK) and glucose-6-phosphate dehydrogenase (G-6-PDH) in glycolytic and pentose phosphate pathway (PPP) during healing of carrots. Taken together, hot water can regulate ROS homeostasis and activate sucrose metabolism, glycolysis and PPP pathway to benefit carrot wound healing.