Effects Of Low Voltage Electrostatic Field And UV-C Treatment On Callus Effect Of Postharvest Potato Tubers

China is a big country in potato production,export and consumption,with the planting area and yield ranking first in the world.However,potato skins are susceptible to mechanical damage such as cuts,abrasions and bumps during field harvesting,transportation,and market circulation.Mechanical wounds on the surface of the tubers will not only accelerate water transpiration,but also contribute to the invasion of pathogenic bacteria.The infection provides a channel,which leads to the occurrence of postharvest potato disease,which indirectly causes significant economic losses.Although potato tubers can naturally form callus at the injury site to effectively inhibit the water transpiration of the tuber and enhance the ability to resist external damage,the natural callus takes a long time,and in actual production activities,usually in the tuber injury wound potato tubers are put into storage or marketed under the condition of incomplete healing,which leads to the occurrence of rot during storage.At present,some chemical treatments such as salicylic acid,abscisic acid,benzothiazide,etc.have been reported to promote the callus of postharvest potato tubers,but chemical treatments are easy to remain.It is of great significance to improve the callus effect of post-potato and improve its storage quality.This paper takes potato as the experimental object to study the effects of low-voltage electrostatic field treatment and short-wave ultraviolet treatment(Ultraviolet-C,UV-C)on postharvest potato tuber callus,in order to provide a method and theoretical basis for postharvest potato tuber rapid callus.The results of the study are as follows:1.The effect of low voltage electrostatic field(LVEF)treatment on the callus effect of postharvest potato tubers:In this experiment,the potato"Jizhangshu No.12"was used as the experimental material.Calling was carried out under low-voltage electrostatic field and under normal temperature and dark conditions without low-voltage electrostatic field,and the weight loss rate,wound hardness,browning degree,respiration intensity,key enzyme activities and metabolites of phenylpropane metabolism during tuber callus were measured.The change of content,and the effect of low-voltage electrostatic field treatment on peroxidase(POD),polyphenol oxidase(PPO)activity and H₂O₂content were analyzed to evaluate the callus effect.The results showed that during the callus period,LVEF treatment could effectively reduce the weight loss of damaged tubers,and effectively promote the accumulation of suberin polyphenolic(SPP),suberin poly aliphatic(SPA)and lignin in postharvest potato tuber callus,and significantly promote the increase of browning degree and hardness at the injury site,significantly increase the PAL activity in callus,and can promote the increase of total phenolic,flavonoid and lignin content.In addition,LVEF treatment was able to increase PPO,POD activity and H₂O₂content in tuber wounds.The results showed that low-voltage electrostatic field treatment could promote the callus of postharvest potato tubers.2.Effects of short-wave UV-C treatment on postharvest potato tubers callus:In this experiment,"Yutian No.806"potato was used as the experimental material.After artificially simulated mechanical damage,it was placed at room temperature and protected from light for healing.After 24 h of callus,the damaged surface was irradiated with four different doses of UV-C 0 k J/m~2,0.1 k J/m~2,0.3 k J/m~2,and 0.5 k J/m~2,and a series of callus-related indicators were measured to evaluate healing effect.The results showed that low dose UV-C treatment of 0.1 k J/m~2,0.3 k J/m~2and 0.5 k J/m~2could promote the accumulation of SPP,SPA and Lignin cell layer thickness in the injured tissue of potato tuber,to increase the activity of PAL,PPO,POD,the synthesis of total phenol,flavonoids and Lignin,the hardness and the content of H₂O₂on the surface of the injured tuber,the weight loss rate of potato tubers during the callus period was significantly reduced.However,0.3 k J/m~2and 0.5 k J/m~2could lead to the moldy phenomenon of some tubers,which caused a certain loss,while 0.1 k J/m~2had no such phenomenon and was the optimal treatment.3.Effects of low-voltage electrostatic field combined with UV-C treatment on postharvest potato callus:In this experiment,the"Holland No.7"potato was used as the experimental material,and the artificially damaged tubers were treated with low-voltage electrostatic field,0.1 k J/m~2UV-C irradiation treatment and the synergistic treatment of the two,the callus was carried out under the dark condition of room temperature,and the callus effect was evaluated by measuring a series of indicators related to the callus.The results showed that:LVEF treatment,UV-C 0.1 k J/m~2treatment and synergistic treatment could increase the accumulation of SPP,SPA and lignin cell layer in the wound tissue of injured tuber to varying degrees,increase PAL,The activities of PPO and POD enzymes increase the content of total phenols,flavonoids,lignin and H₂O₂,improve the hardness value,browning degree value and respiration intensity of the wound tissue surface,and significantly reduce the weight loss of postharvest potato tubers during the callus period Among them,in the early stage of callus,UV-C 0.1 k J/m~2treatment was better than LVEF treatment,and in the later stage of callus,LVEF treatment was better than UV-C0.1 k J/m~2treatment,and the synergistic treatment combined the two to get the best effect.