Preliminary Study On The Mechanism Of Promoting Wound Curing Of Yam Tuber Treated By Temperature And Chemicalagent

Yam tubers are long and easy to break,It is incure wounds during harvesting,transportation,and sales,which causes sensory changes,browning,water loss and infection,which reduce the food quality and processing value.In this experiment,yam was used as materials,the effect of different temperatures on the wound curing process of cutting yam was studied,including the changes of disease resistance and weightlessness,and the histochemical localization observation of the SPP and lignin content during wound curing.Based on this,exploring the changes of phenolic metabolism and active oxygen metabolism during wound curing at different temperatures.Further more combined several agents at the optimal callus temperature,the optimal compound conditions for wound curing of yam tubers were screened out.The result is as follows:?1?The influence of temperature on the wound curing process of yam was studied within the temperature range of 5°C-35°C?relative humidity RH 85%?.The decay diameter,weight loss rate and quality index:total sugar,reducing suger content and soluble protein content of the temperature treatment groups during wound curing were determined.The ability of wound curing was compared between the temperature treatment groups,the SPP and lignin accumulation were were stained and assayed during the process.Compared with different temperature treatments,it was found that curing at35°C could effectively improve the disease resistance of the yam,the plaque diameter was smaller than other temperature treatment groups,and the weight loss rate at 35°C during wound curing was higher,but it was lower than other temperature treatment groups after wound curing was completed.The content of lignin during wound curing was higher than that of other treatments.Raising wound curing temperature could promote the wound curing process,curing at 35?improved the activity of PAL and PPO enzymes and the content of total phenols and flavonoids effectively.And also SOD and POD activity were improved,H₂O₂ content and the production rate of superoxide anion increased.Based on the above findings,the optimal wound healing condition for the final selection of yam tubers was 35°C.?2?The effects of several chemical agent?BABA,2,4-D,NaHCO₃?on yam tubers at the optimal callus temperature were further studied.The most optimal chemical agent concentrations were screened by disease resistance determination.The optimal concentration of BABA was 1 mmol/L,the optimal concentration of NaHCO₃ was 1mmol/L,the optimal concentration of 2,4-D was 0.125 mmol/L.yam tubers were treated with 1 mmol/L BABA?T1?,0.0125mmol/L 2,4-D?T2?,1 mmol/L NaHCO₃?T3?,1 mmol/L BABA+1 mmol/L NaHCO₃?T4?and 0.0125 mmol/L 2,4-D+1 mmol/L NaHCO₃?T5?at35°C respectively.Comparing the rot diameter and the weight loss rate of wound curing for 3 days;the histochemical localization of SPP and lignin was observed and the secondary metabolism was determined,including total phenolic and flavonoid contents,changes in PAL and PPO enzyme activities,H₂O₂ content,superoxide anion production rate,and activity of SOD,CAT and POD enzymes.The results showed that the effect of35?combin with the chemical agent was superior to that of 35°C treatment alone,and the combination treatment of the chemical agent could reduce the diameter of the rot.The combination treatment of the chemical agent resulted in the earlier accumulation of SPP and lignin.Chemical agents combination treatment to some extent enhances the phenolic metabolic activity and active oxygen metabolic activity.It showed that the treatment with the combination of chemical agents could enhance the wound curing process;compared with other treatment groups,the rot diameter was the smallest of the T4 compound chemical agent treatment,the SPP and lignin accumulated ahead of time;the activity of PAL,PPO,POD,SOD,and CAT were maintained at a higher level,lignin,total phenols,and flavonoids increased.Treatment with T4 improved the resistance of tubers to yam,and promoted the formation of suberization more quickly than other treatments.