Study on the relationship of cold resistance of peach tree by different methods
Three peach varieties with strong,medium and weak cold resistance during production were selected as test materials,the changes of cold resistance and EIS parameters of branches without freezing treatment at different periods were studied by electrolytic osmosis(EL)and electrical impedance mapping(EIS),the relationship between EIS parameters of branches without freezing treatment and the semi-lethal temperature estimated by EL method was statistically analyzed,the relationship between the semi-lethal temperature estimated by EIS and the semi-lethal temperature estimated by EL method was statistically analyzed.The results showed that the extracellular resistivity(r)and intracellular resistivity(r)of the three varieties without freezing increased with the decrease of external temperature,and decreased with the increase of external temperature,relaxation time(τ)with re and ri in opposite change tendency;According to the statistical analysis of the four electrical impedance parameters and the semi-lethal temperature estimated by EL method,EIS(r)is the best parameter,the correlation coefficient is-0.828,the path coefficient is-7.385,the linear regression equation is y=-4.063 9x+4.333 8,R2=0.686.The cold resistance of three peach varieties measured by EL method and EIS parameter method was consistent with the cold resistance in production.The statistical analysis of the two methods shows that EL method and EIS four parameter methods have extremely significant positive correlation with cold resistance,and the correlation coefficient,path coefficient and determination coefficient of the method of relaxation time are the highest.Therefore,relaxation time is an appropriate parameter for predicting cold resistance of frozen peach branches.