Promoting Effects Of Postharvest ASM Treatment On Wound Healing Of Potato Tubers And Its Mechanism

Wound healing is a typical response for potato tubers after wounding,which plays an important role in reducing postharvest disease of tubers.However,in consideration of about 4weeks was needed when completely healing under normal circumstances,effectively measures should be taken to promote wound healing.In this study,the dominant potato cultivar?Longshu No.3‘in Northwest of China was used as materials.The artificially damaged tubers were dipped in ASM at 100mg/L for 10 minutes and treated with plasma membrane hydrogen peroxide blocker DPI.The accumulation of lignin and suberin were observed at the wound site,The changes of key enzymes and products of reactive oxygen and Phenylpropane metabolism in callus were determined,and their roles in callus were determined.The results showed as follow:1.The healing effects of ASM treatment were better than the control.ASM treatment can effectively inhibit the disease index and maintain a lower incidence of potato tuber which were damaged section inoculation of F.sulphureum during wound healing.Those results of incidence and disease index of ASM treatment were significantly lower than that of DPI combined treatment.ASM treatment can maintain a lower rate of weight loss during wound healing of potato tubers.2.ASM treatment significantly enhanced the activities of NOX and SOD in callus of potato tubers,and then promoted the accumulation of O₂.^-and H₂O₂ which respectively peaked at 8 h,14 d and 12 h,14 d earlier than that of control,peaked at 24 h.DPI combined treatment can significantly inhibit the activities of NOX and SOD induced by ASM and reduce the accumulation of ROS in tuber callus.It shows that ASM treatment can promote and accelerate the accumulation of ROS in callus.3.ASM treatment can effectively increase the activity of key enzymes in the phenylpropanoid pathway of potato callus,and can promote the activity of POD and PPO,thus promoting the accumulation of phenylpropanoid metabolites,and the peak of PAL and C4H were appeared at 24 h,14 d and 3 d,14 d;4CL peaked at 3d,CAD and F5H peaked at14d during wound healing of potato tubers.Considering the accumulation of Reactive oxygen and the changes of phenylpropane metabolism,the time of Reactive oxygen accumulation,8h and 12h,prior to the time of phenylpropanol metabolism activity indicating that reactive oxygen may as a signal molecule play an important role during wound healing of potato tubers.DPI combined treatment can significantly inhibit henylpropanoid metabolism,as the the activity of PAL,4CL,C4H and CAD treated by were significantly lower than that of the control.4.ASM treatment increased the number of callus cells,accelerated the accumulation of SPP?Suberin polyphenolics?and SPA?Suberin poly aliphatics?,and promoted wound healing.In conclusion,ASM treatment induced ROS the accumulation of ROS in callus of potato tubers,which H₂O₂ and POD mediate the oxidation and cross-linking reaction of callus cell wall,strengthen the cell wall and promote callus,on the other hand,ROS act as an upstream signal inducer accelerating the phenylpropanoid metabolism during healing which initiation Accumulation of phenols and lignin in callus promotes the suppository effect to accelerate the callus of the potato and enhance the effects of healing.