Study On Cold Resistance Of Three Kinds Of Appreciate Branch Plants

In order to enrich the northern winter plant landscape,In this paper,take Rosa davurica × rugosa Thunb.,Euonymus maackii Rupr.and Salix alba L.as experimental materials,under the stress of artificial low temperature,Identification of cold resistance of branches under different low temperature treatments by EL and EIS.At the same time,the physiological indexes of annual branches were measured and the germination of three kinds of appreciate branch plants was observed by the method of restoring growth.After that,the cold resistance of three kinds of appreciate branch plants was evaluated by the statistics of the rate of diseased branches and the rate of damaged buds.Finally,the mathematical model was used to systematically evaluate the cold resistance of three kinds of appreciate branch plants by variance analysis,multiple comparison,principal component analysis and membership function.This study provided theoretical basis and beneficial reference for the application of the three kinds of appreciate branch plants in northern China.The main research result are as follows:(1)The cold resistance three kinds of appreciate branch plants was preliminary compared by EL and EIS.With the decrease of temperature,the relative electrical conductivity of the three kinds of appreciate branch plants increased gradually,extracellular resistance declined gradually.The relative conductivity,and extracellular resistance were used to fit the logistic equation and calculate the half lethal temperature of three kinds of appreciate branch plants,The results showed that the half lethal temperature of three kinds of appreciate branch plants fitted by EL method was lower than that fitted by EIS,but the order of the half lethal temperature of the three kinds of appreciate branch plant sis the same through EL and EIS.The order of cold resistance of three kinds of appreciate branch plants was as follows:Euonymus maackii>Salix alba>Rosa davurica x rugos’a.(2)With the decrease of temperature,water absorption in the branches of three kinds of appreciate branch plants declined gradually,no obvious change in water content.The results showed that there were significant differences in the water content and water absorption of three kinds of appreciate branch plants under different low temperature levels through single factor analysis of variance and multiple comparison.(3)With the decrease of temperature,the soluble sugar content,soluble protein content and proline content in the branches of the three kinds of appreciate branch plants increased first and then decreased.The results showed that there were significant differences in the soluble sugar content、soluble protein content and proline content in the branches of three kinds of appreciate branch plants under different low temperature levels through single factor analysis of variance and multiple comparison.(4)With the decrease of temperature,the MDA content in the branches of three kinds of appreciate branch plants increased first and then decreased,the activity of SOD in the branches of Rosa davurica × rugosa increased first and then decreased,the activity of SOD in the branches of Euonymus maackii and Salix alba decreased at the beginning of cooling,and then increased with the decrease of temperature.When it reaches a certain peak,it begins to decline.However,the peak value of SOD activity was different among the three kinds of appreciate branches plant.Single factor analysis of variance and multiple comparison of SOD activity and MDA content in the branches of the three kinds of appreciate branch plants at different low temperature levels,the results showed that there was no significant difference in MDA content of the three kinds of appreciate branches plant,but significant difference in SOD activity(P<0.01).(5)Under different low temperature stress conditions,the germination rate of three kinds of appreciate branch plants showed a downward trend,and the degree of decline was different.When the temperature reaches-25℃,the germination rate of Rosa davurica ×rugosa is zero,when the temperature reached-40 ℃,the germination rates of Euonymus maackii and Salix alba could reach 50.2%and 42.6%.Single factor analysis of variance and multiple comparison of germination rates of three kinds of appreciate branch plants under different low temperature levels,the result showed that there was a significant difference in germination rates among Rosa davurica × rugosa,Salix alba and Euonymus maackii(P<0.01),but there was no significant difference between Euonymus maackii and Salix alba(P<0.01)(6)The correlation analysis of eight cold resistance physiological indexes of three kinds of appreciate branch plants under low temperature stress was carried out,the results showed that SOD content was extremely significant positively correlated with MDA content and soluble sugar content,significant positively correlated with soluble protein content,and extremely significant negatively correlated with MDA content;the soluble sugar content was significant negatively correlated with relative conductivity,and significant positively correlated with proline content;MDA content was extremely significant negatively correlated with relative conductivity.(7)Principal component analysis was applied to the physiological indexes(relative conductivity,water content,water absorption,soluble sugar,soluble protein,SOD,MDA,proline)of dormant annual branches of three kinds of appreciate branch plants under low temperature stress.according to the weight of cold resistance index,water content,SOD,proline,electrical conductivity and MDA are closely related to the cold resistance of three kinds of appreciate branches plant.The cold resistance ability of the Combined with the membership function,the cold resistance ability of the three kinds of appreciate branch plants was evaluated as follows:Euonymus maackii>Salix alba>Rosa davurica ×rugosa.The results are consistent with the order of cold resistance of the semi lethal temperature obtained by EL and EIS combined with logistic equation.(8)The overwintering adaptability of three kinds of appreciate branch plants branches was evaluated in cultivated by the rates of diseased branches and damaged buds,the results showed that the cold resistance grade of three kinds of appreciate branch plants was grade Ⅱ,they belongs to the tree species with strong cold resistance.There was slight frostbite in the cultivated land,but it did not affect its normal development and appreciate in the second year.